Search for "structural features" in Full Text gives 209 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Beilstein J. Org. Chem. 2014, 10, 2215–2221, doi:10.3762/bjoc.10.229
Graphical Abstract
Figure 1: Erythromycin (1), the archetypal macrolide; sophorlipid lactone 2, a glycolipid macrolactone; β-D-g...
Scheme 1: Synthesis of macrolides 5 and 6 by a ring closing metathesis strategy.
Figure 2: Structure of macrolide 3; a) schematic representation of 3 emphasizing four-atom planar units of th...
Figure 3: Structures of 5 and 6 from X-ray crystallographic data; a) and b) side views of 5 (a) and 6 (b) wit...
Beilstein J. Org. Chem. 2014, 10, 2186–2199, doi:10.3762/bjoc.10.226
Graphical Abstract
Figure 1: General structures of biologically active dihydroisoquinolines, THIQs and 1,2-diarylindoles.
Scheme 1: Li’s THIQ indolation protocol.
Scheme 2: Possible strategies for the synthesis of target structure 1. Dashed arrows indicate literature-know...
Scheme 3: Nucleophilic substitution of DMEDA with 2-fluoro-3-iodopyridine (10).
Scheme 4: Decomposition of 1-(indol-3-yl)-THIQ 4d during N-arylation (monitored by GC–MS).
Scheme 5: Formation of byproduct 13 via benzylic oxidation.
Scheme 6: Routes towards 1,2-diarylindoles starting from indole; a: PhB(OH)2 (3 equiv), Pd(OAc)2 (5 mol %), A...
Scheme 7: Palladium-catalyzed C2-arylation attempt of 1-(1-phenylindol-3-yl)-N-Boc-THIQ.
Beilstein J. Org. Chem. 2014, 10, 2175–2185, doi:10.3762/bjoc.10.225
Graphical Abstract
Scheme 1: Studied DBTAA–adenine conjugates (AP3, AP3am, AP5, AP6) [11], and the reference compounds lacking adeni...
Scheme 2: Preparations of the products AP3am and AP5. Starting compounds were synthesized according to previo...
Figure 1: Changes in the UV–vis spectrum of AP3am (c = 1.0 × 10−5 mol dm−3) upon titration with poly dA–poly ...
Figure 2: Induced CD bands observed for AP3, AP3am, AP6 for poly dA–poly dT and poly (dAdT)2 (c = 3.0 × 10−5 ...
Figure 3: Comparison of AP3 ICD bands for ss-DNA (dA and dT) with alternating- and homo-AT ds-polynucleotides...
Figure 4: Self-folding of AP5 (upper left – note the stacking of DBTAA and adenine) and AP3 (lower left – not...
Figure 5: Schematic presentation of self-folded AP5 (free AP5 see Figure 4; upper left) in the minor groove of poly d...
Beilstein J. Org. Chem. 2014, 10, 2089–2121, doi:10.3762/bjoc.10.218
Graphical Abstract
Figure 1: Cyclic chiral phosphines based on bridged-ring skeletons.
Figure 2: Cyclic chiral phosphines based on binaphthyl skeletons.
Figure 3: Cyclic chiral phosphines based on ferrocene skeletons.
Figure 4: Cyclic chiral phosphines based on spirocyclic skeletons.
Figure 5: Cyclic chiral phosphines based on phospholane ring skeletons.
Figure 6: Acyclic chiral phosphines.
Figure 7: Multifunctional chiral phosphines based on binaphthyl skeletons.
Figure 8: Multifunctional chiral phosphines based on amino acid skeletons.
Scheme 1: Asymmetric [3 + 2] annulations of allenoates with electron-deficient olefins, catalyzed by the chir...
Scheme 2: Asymmetric [3 + 2] annulations of allenoate and enones, catalyzed by the chiral binaphthyl-based ph...
Scheme 3: Asymmetric [3 + 2] annulations of N-substituted olefins and allenoates, catalyzed by the chiral bin...
Scheme 4: Asymmetric [3 + 2] annulations of 2-aryl-1,1-dicyanoethylenes with ethyl allenoate, catalyzed by th...
Scheme 5: Asymmetric [3 + 2] annulations of 3-alkylideneindolin-2-ones with ethyl allenoate, catalyzed by the...
Scheme 6: Asymmetric [3 + 2] annulations of 2,6-diarylidenecyclohexanones with allenoates, catalyzed by the c...
Scheme 7: Asymmetric [3 + 2] annulations of allenoate with alkylidene azlactones, catalyzed by the chiral bin...
Scheme 8: Asymmetric [3 + 2] annulations of C60 with allenoates, catalyzed by the chiral phosphine B6.
Scheme 9: Asymmetric [3 + 2] annulations of α,β-unsaturated esters and ketones with an allenoate, catalyzed b...
Scheme 10: Asymmetric [3 + 2] annulations of exocyclic enones with allenoates, catalyzed by the ferrocene-modi...
Scheme 11: Asymmetric [3 + 2] annulations of enones with an allenylphosphonate, catalyzed by the ferrocene-mod...
Scheme 12: Asymmetric [3 + 2] annulations of 3-alkylidene-oxindoles with ethyl allenoate, catalyzed by the fer...
Scheme 13: Asymmetric [3 + 2] annulations of dibenzylideneacetones with ethyl allenoate, catalyzed by the ferr...
Scheme 14: Asymmetric [3 + 2] annulations of trisubstituted alkenes with ethyl allenoate, catalyzed by the fer...
Scheme 15: Asymmetric [3 + 2] annulations of 2,6-diarylidenecyclohexanones with allenoates, catalyzed by the f...
Scheme 16: Asymmetric [3 + 2] annulations of α,β-unsaturated ketones with ethyl allenoates, catalyzed by the f...
Scheme 17: Asymmetric [3 + 2] annulations of α,β-unsaturated esters with allenoates, catalyzed by the ferrocen...
Scheme 18: Asymmetric [3 + 2] annulations of alkylidene azlactones with allenoates, catalyzed by the chiral sp...
Scheme 19: Asymmetric [3 + 2] annulations of α-trimethylsilyl allenones and electron-deficient olefins, cataly...
Scheme 20: Asymmetric [3 + 2] annulations of α,β-unsaturated ketones with an allenone, catalyzed by the chiral...
Scheme 21: Asymmetric [3 + 2] annulations of cyclic enones with allenoates, catalyzed by the chiral α-amino ac...
Scheme 22: Asymmetric [3 + 2] annulations of arylidenemalononitriles and analogues with an allenoate, catalyze...
Scheme 23: Asymmetric [3 + 2] annulations of α,β-unsaturated esters with an allenoate, catalyzed by the chiral...
Scheme 24: Asymmetric [3 + 2] annulations of 3,5-dimethyl-1H-pyrazole-derived acrylamides with an allenoate, c...
Scheme 25: Asymmetric [3 + 2] annulations of maleimides with allenoates, catalyzed by the chiral phosphine H10....
Scheme 26: Asymmetric [3 + 2] annulations of α-substituted acrylates with allenoate, catalyzed by the chiral p...
Scheme 27: Asymmetric [3 + 2] annulation of an N-tosylimine with an allenoate, catalyzed by the chiral phosphi...
Scheme 28: Asymmetric [3 + 2] annulations of N-tosylimines with an allenoate, catalyzed by the chiral phosphin...
Scheme 29: Asymmetric [3 + 2] annulations of N-tosylimines with an allenoate, catalyzed by the chiral phosphin...
Scheme 30: Asymmetric [3 + 2] annulations of N-diphenylphosphinoyl aromatic imines with butynoates, catalyzed ...
Scheme 31: Asymmetric [3 + 2] annulations of N-tosylimines with allenylphosphonates, catalyzed by the chiral p...
Scheme 32: Asymmetric [3 + 2] annulation of an N-tosylimine with an allenoate, catalyzed by the chiral phosphi...
Scheme 33: Asymmetric [3 + 2] annulations of N-diphenylphosphinoyl aromatic imines with allenoates (top), cata...
Scheme 34: Asymmetric [3 + 2] annulation of N-diphenylphosphinoylimines with allenoates, catalyzed by the chir...
Scheme 35: Asymmetric [3 + 2] annulation of an azomethine imine with an allenoate, catalyzed by the chiral pho...
Scheme 36: Asymmetric [3 + 2] annulations between α,β-unsaturated esters/ketones and 3-butynoates, catalyzed b...
Scheme 37: Asymmetric intramolecular [3 + 2] annulations of electron-deficient alkenes and MBH carbonates, cat...
Scheme 38: Asymmetric [3 + 2] annulations of methyleneindolinone and methylenebenzofuranone derivatives with M...
Scheme 39: Asymmetric [3 + 2] annulations of activated isatin-based alkenes with MBH carbonates, catalyzed by ...
Scheme 40: Asymmetric [3 + 2] annulations of maleimides with MBH carbonates, catalyzed by the chiral phosphine ...
Scheme 41: A series of [3 + 2] annulations of various activated alkenes with MBH carbonates, catalyzed by the ...
Scheme 42: Asymmetric [3 + 2] annulations of an alkyne with isatins, catalyzed by the chiral phosphine F1.
Scheme 43: Asymmetric [4 + 2] annulations catalyzed by the chiral phosphine B1.
Scheme 44: Asymmetric [4 + 2] annulations catalyzed by the chiral phosphine H5.
Scheme 45: Asymmetric [4 + 2] annulations catalyzed by the chiral phosphines H13 and H12.
Scheme 46: Asymmetric [4 + 2] annulations catalyzed by the chiral phosphine H6.
Scheme 47: Kerrigan’s [2 + 2] annulations of ketenes with imines, catalyzed by the chiral phosphine B7.
Scheme 48: Asymmetric [4 + 1] annulations, catalyzed by the chiral phosphine G6.
Scheme 49: Asymmetric homodimerization of ketenes, catalyzed by the chiral phosphine F5 and F6.
Scheme 50: Aza-MBH/Michael reactions, catalyzed by the chiral phosphine G1.
Scheme 51: Tandem RC/Michael additions, catalyzed by the chiral phosphine H14.
Scheme 52: Intramolecular tandem RC/Michael addition, catalyzed by the chiral phosphine H15.
Scheme 53: Double-Michael addition, catalyzed by the chiral aminophosphine G9.
Scheme 54: Tandem Michael addition/Wittig olefinations, mediated by the chiral phosphine BIPHEP.
Scheme 55: Asymmetric Michael additions, catalyzed by the chiral phosphines H7, H8, and H9.
Scheme 56: Asymmetric γ-umpolung additions, catalyzed by the chiral phosphine A1.
Scheme 57: Asymmetric γ-umpolung additions, catalyzed by the chiral phosphines E2 and E3.
Scheme 58: Intramolecular γ-additions of hydroxy-2-alkynoates, catalyzed by the chiral phosphine D2.
Scheme 59: Intra-/intermolecular γ-additions, catalyzed by the chiral phosphine D2.
Scheme 60: Intermolecular γ-additions, catalyzed by the chiral phosphines B5 and B3.
Scheme 61: Intermolecular γ-additions, catalyzed by the chiral phosphines E6 and B4.
Scheme 62: Asymmetric allylic substitution of MBH acetates, catalyzed by the chiral phosphine G2.
Scheme 63: Allylic substitutions between MBH acetates or carbonates and an array of nucleophiles, catalyzed by...
Scheme 64: Asymmetric acylation of diols, catalyzed by the chiral phosphines E4 and E5.
Scheme 65: Kinetic resolution of secondary alcohols, catalyzed by the chiral phosphine E8 and E9.
Beilstein J. Org. Chem. 2014, 10, 2013–2020, doi:10.3762/bjoc.10.209
Graphical Abstract
Scheme 1: Planar and layered ethynyl aromatics as building blocks for extended aromatic structures.
Scheme 2: Previous coupling experiments with pseudo-ortho-diethynyl[2.2]paracyclophane 4.
Scheme 3: Glaser coupling of pseudo-gem-diethynyl[2.2]paracyclophane 2.
Scheme 4: Glaser coupling of pseudo-ortho-diethynyl[2.2]paracyclophane, 4.
Figure 1: Above: The molecule of compound 11 in the crystal; ellipsoids represent 30% probability levels. Onl...
Figure 2: Above: The molecule of compound 12 in the crystal; ellipsoids represent 50% probability levels. Onl...
Scheme 5: Sonogashira coupling of aldehyde 13 with ortho-diiodobenzene (14).
Scheme 6: Preparation of benzologs of dimers 11/12.
Figure 3: Above: The molecule of compound 19 in the crystal; ellipsoids represent 50% probability levels. Sol...
Figure 4: Above: One of the three independent molecules of compound 20 in the crystal; ellipsoids represent 3...
Scheme 7: Cross dimerization of 1 and 4.
Figure 5: The molecule of compound 22 in the crystal; ellipsoids represent 50% probability levels.
Scheme 8: An attempt to prepare a biphenylenophane.
Figure 6: The molecule of compound 26 in the crystal; ellipsoids represent 50% probability levels.
Beilstein J. Org. Chem. 2014, 10, 1848–1877, doi:10.3762/bjoc.10.195
Graphical Abstract
Figure 1: Examples of phosphonamide reagents used in stereoselective synthesis.
Figure 2: Natural products and bioactive molecules synthesized using phosphonamide-based chemistry (atoms, bo...
Scheme 1: Olefination with cyclic phosphonamide anions, mechanistic rationale, and selected examples 27a–d [18].
Scheme 2: Asymmetric olefination with chiral phosphonamide anions and selected examples 31a–d [1,22].
Scheme 3: Synthesis of α-substituted phosphonic acids 33a–e by asymmetric alkylation of chiral phosphonamide ...
Scheme 4: Asymmetric conjugate additions of C2-symmetric chiral phosphonamide anions to cyclic enones, lacton...
Scheme 5: Asymmetric conjugate additions of P-chiral phosphonamide anions generated from 40a and 44a to cycli...
Scheme 6: Asymmetric cyclopropanation with chiral chloroallyl phosphonamide 47, mechanistic rationale, and se...
Scheme 7: Asymmetric cyclopropanation with chiral chloromethyl phosphonamide 28d [59].
Scheme 8: Stereoselective synthesis of cis-aziridines 57 from chiral chloroallyl phosphonamide 47a [62].
Scheme 9: Synthesis of phosphonamides by (A) Arbuzov reaction, (B) condensation of diamines with phosphonic a...
Figure 3: Original and revised structure of polyoxin A (69) [24-26].
Scheme 10: Synthesis of (E)-polyoximic acid (9) [24-26].
Figure 4: Key assembly strategy of acetoxycrenulide (10) [41,42].
Scheme 11: Total synthesis of (+)-acetoxycrenulide (10) [41,42].
Scheme 12: Synthesis squalene synthase inhibitor 19 by asymmetric sulfuration (A) and asymmetric alkylation (B...
Figure 5: Key assembly strategy of fumonisin B2 (20) and its tricarballylic acid fragment 105 [45,46].
Scheme 13: Final steps of the total synthesis of fumonisin B2 (20) [45,46].
Figure 6: Selected examples of two subclasses of β-lactam antibiotics – carbapenems (111 and 112) and trinems...
Scheme 14: Synthesis of tricyclic β-lactam antibiotic 123 [97].
Scheme 15: Total synthesis of (−)-anthoplalone (8) [56].
Figure 7: Protein tyrosine phosphatase (PTP) inhibitors 130, 131 and model compounds 16, 132 and 133 [68].
Scheme 16: Synthesis of model PTP inhibitors 16a,b [68].
Scheme 17: Synthesis of aziridine hydroxamic acid 17 as MMP inhibitor [63].
Scheme 18: Synthesis of methyl jasmonate (11) [48].
Figure 8: Structures of nudiflosides A (137) and D (13) [49].
Scheme 19: Total synthesis of the pentasubstituted cyclopentane core 159 of nudiflosides A (151) and D (13) an...
Figure 9: L-glutamic acid (161) and constrained analogues [57,124].
Scheme 20: Stereoselective synthesis of DCG-IV (162) [57].
Scheme 21: Stereoselective synthesis of mGluR agonist 21 [124].
Figure 10: Key assembly strategy of berkelic acid (15) [43].
Scheme 22: Total synthesis of berkelic acid (15) [43].
Figure 11: Key assembly strategy of jerangolid A (22) and ambruticin S (14) [27,28].
Scheme 23: Final assembly steps in the total synthesis of jerangolid A [27].
Scheme 24: Key assembly steps in the total synthesis of ambruticin S (14) [28].
Figure 12: General steroid construction strategy based on conjugate addition of 212 to cyclopentenone 48, exem...
Scheme 25: Total synthesis of estrone (12) [44].
Beilstein J. Org. Chem. 2014, 10, 1840–1847, doi:10.3762/bjoc.10.194
Graphical Abstract
Figure 1: Chemical structures and carbon numbering scheme of tricyclo(tc)-DNA (top, left), bicyclo(bc)-DNA (t...
Scheme 1: Conditions: (a) NaBH4, CeCl3·7H2O, MeOH, −78 °C → rt, 1.5 h, 73% (+9% of C6-epimer); (b) TBS-Cl, im...
Scheme 2: Conditions: (a) thymine, BSA, TMSOTf, TMSCl, CH3CN, rt, 2.5 h; (b) DMTrCl, pyridine, rt, 16 h, 29% ...
Figure 2: X-ray structure of top row: nucleosides 8β (left), 11β (center) and overlay of both structures (rig...
Scheme 3: Pathways for elimination of the modified nucleotides during the oxidation step in oligonucleotide a...
Beilstein J. Org. Chem. 2014, 10, 1630–1637, doi:10.3762/bjoc.10.169
Graphical Abstract
Scheme 1: Modular titanocene synthesis via acylation reactions [24].
Figure 1: Carboxylates employed as titanocene starting materials for azide-substituted complexes.
Figure 2: Azides employed in this study and conditions for their synthesis.
Figure 3: Most active titanocenes of this study and their AC50 values.
Beilstein J. Org. Chem. 2014, 10, 1267–1271, doi:10.3762/bjoc.10.127
Graphical Abstract
Scheme 1: General transformation of selenides to selenones.
Scheme 2: Phenylselenone 2 as useful leaving group for the synthesis of different organic molecules.
Beilstein J. Org. Chem. 2014, 10, 1166–1196, doi:10.3762/bjoc.10.117
Graphical Abstract
Scheme 1: Pioneer works of Atherton, Openshaw and Todd reporting on the synthesis of phosphoramidate starting...
Scheme 2: Mechanisms 1 (i) and 2 (ii) suggested by Atherton and Todd in 1945; adapted from [1].
Scheme 3: Two reaction pathways (i and ii) to produce chlorophosphate 2. Charge-transfer complex observed whe...
Scheme 4: Mechanism of the Atherton–Todd reaction with dimethylphosphite according to Roundhill et al. (adapt...
Scheme 5: Synthesis of dialkyl phosphate from dialkyl phosphite (i) and identification of chloro- and bromoph...
Scheme 6: Synthesis of chiral phosphoramidate with trichloromethylphosphonate as the suggested intermediate (...
Scheme 7: Selection of results that address the question of the stereochemistry of the AT reaction (adapted f...
Scheme 8: Synthesis of phenoxy spirophosphorane by the AT reaction (adapted from [34]).
Scheme 9: Suggested mechanism of the Atherton–Todd reaction, (i) and (ii) formation of chlorophosphate with a...
Scheme 10: AT reaction in biphasic conditions (adapted from [38]).
Scheme 11: AT reaction with iodoform as halide source (adapted from [37]).
Scheme 12: AT reaction with phenol at low temperature in the presence of DMAP (adapted from [40]).
Scheme 13: Synthesis of a triphosphate by the AT reaction starting with the preparation of chlorophosphate (ad...
Scheme 14: AT reaction with sulfonamide (adapted from [42]).
Scheme 15: Synthesis of a styrylphosphoramidate starting from the corresponding aniline (adapted from [43]).
Scheme 16: Use of hydrazine as nucleophile in AT reactions (adapted from [48]).
Scheme 17: AT reaction with phenol as a nucleophilic species; synthesis of dioleyl phosphate-substituted couma...
Scheme 18: Synthesis of β-alkynyl-enolphosphate from allenylketone with AT reaction (adapted from [58]).
Scheme 19: Synthesis of pseudohalide phosphate by using AT reaction (adapted from [67]).
Scheme 20: AT reaction with hydrospirophosphorane with insertion of CO2 in the product (adapted from [69]).
Scheme 21: AT reaction with diaryl phosphite (adapted from [70]).
Scheme 22: AT reaction with O-alkyl phosphonite (adapted from [71]).
Scheme 23: Use of phosphinous acid in AT reactions (adapted from [72]).
Scheme 24: AT reaction with secondary phosphinethiooxide (adapted from [76]).
Scheme 25: Use of H-phosphonothioate in the AT reaction (adapted from [78]).
Scheme 26: AT-like reaction with CuI as catalyst and without halide source (adapted from [80]).
Scheme 27: Reduction of phenols after activation as phosphate derivatives (adapted from [81] i ; [82], ii; and [83], iii).
Scheme 28: Synthesis of medium and large-sized nitrogen-containing heterocycles (adapted from [85]).
Scheme 29: Synthesis of arylstannane from aryl phosphate prepared by an AT reaction (adapted from [86]).
Scheme 30: Synthesis and use of aryl dialkyl phosphate for the synthesis of biaryl derivatives (adapted from [89])....
Scheme 31: Synthesis of aryl dialkyl phosphate by an AT reaction from phenol and subsequent rearrangement yiel...
Scheme 32: Selected chiral phosphoramidates used as organocatalyst; i) chiral phosphoramidate used in the pion...
Scheme 33: Determination of ee of H-phosphinate by the application of the AT reaction with a chiral amine (ada...
Scheme 34: Chemical structure of selected flame retardants synthesized by AT reactions; (BDE: polybrominated d...
Scheme 35: Transformation of DOPO (i) and synthesis of polyphosphonate (ii) by the AT reaction (adapted from [117] ...
Scheme 36: Synthesis of lipophosphite (bisoleyl phosphite) and cationic lipophosphoramidate with an AT reactio...
Scheme 37: Use of AT reactions to produce cationic lipids characterized by a trimethylphosphonium, trimethylar...
Scheme 38: Cationic lipid synthesized by the AT reaction illustrating the variation of the structure of the li...
Scheme 39: Helper lipids for nucleic acid delivery synthesized with the AT reaction (adapted from [130]).
Scheme 40: AT reaction used to produce red/ox-sensitive cationic lipids (adapted from [135]).
Scheme 41: Alkyne and azide-functionalized phosphoramidate synthesized by AT reactions,(i); illustration of so...
Scheme 42: Cationic lipids exhibiting bactericidal action – arrows indicate the bond formed by the AT reaction...
Scheme 43: β-Cyclodextrin-based lipophosphoramidates (adapted from [138]).
Scheme 44: Polyphosphate functionalized by an AT reaction (adapted from [139]).
Scheme 45: Synthesis of zwitterionic phosphocholine-bound chitosan (adapted from [142]).
Scheme 46: Synthesis of AZT-based prodrug via an AT reaction (adapted from [143]).
Beilstein J. Org. Chem. 2014, 10, 544–598, doi:10.3762/bjoc.10.50
Graphical Abstract
Scheme 1: The proposed mechanism of the Passerini reaction.
Scheme 2: The PADAM-strategy to α-hydroxy-β-amino amide derivatives 7. An additional oxidation provides α-ket...
Scheme 3: The general accepted Ugi-mechanism.
Scheme 4: Three commonly applied Ugi/cyclization approaches. a) UDC-process, b) UAC-sequence, c) UDAC-combina...
Scheme 5: Ugi reaction that involves the condensation of Armstrong’s convertible isocyanide.
Scheme 6: Mechanism of the U-4C-3CR towards bicyclic β-lactams.
Scheme 7: The Ugi 4C-3CR towards oxabicyclo β-lactams.
Scheme 8: Ugi MCR between an enantiopure monoterpene based β-amino acid, aldehyde and isocyanide resulting in...
Scheme 9: General MCR for β-lactams in water.
Scheme 10: a) Ugi reaction for β-lactam-linked peptidomimetics. b) Varying the β-amino acid resulted in β-lact...
Scheme 11: Ugi-4CR followed by a Pd-catalyzed Sn2 cyclization.
Scheme 12: Ugi-3CR of dipeptide mimics from 2-substituted pyrrolines.
Scheme 13: Joullié–Ugi reaction towards 2,5-disubstituted pyrrolidines.
Scheme 14: Further elaboration of the Ugi-scaffold towards bicyclic systems.
Scheme 15: Dihydroxyproline derivatives from an Ugi reaction.
Scheme 16: Diastereoselective Ugi reaction described by Banfi and co-workers.
Scheme 17: Similar Ugi reaction as in Scheme 16 but with different acids and two chiral isocyanides.
Scheme 18: Highly diastereoselective synthesis of pyrrolidine-dipeptoids via a MAO-N/MCR-procedure.
Scheme 19: MAO-N/MCR-approach towards the hepatitis C drug telaprevir.
Scheme 20: Enantioselective MAO-U-3CR procedure starting from chiral pyrroline 64.
Scheme 21: Synthesis of γ-lactams via an UDC-sequence.
Scheme 22: Utilizing bifunctional groups to provide bicyclic γ-lactam-ketopiperazines.
Scheme 23: The Ugi reaction provided both γ- as δ-lactams depending on which inputs were used.
Scheme 24: The sequential Ugi/RCM with olefinic substrates provided bicyclic lactams.
Scheme 25: a) The structural and dipole similarities of the triazole unit with the amide bond. b) The copper-c...
Scheme 26: The Ugi/Click sequence provided triazole based peptidomimetics.
Scheme 27: The Ugi/Click reaction as described by Nanajdenko.
Scheme 28: The Ugi/Click-approach by Pramitha and Bahulayan.
Scheme 29: The Ugi/Click-combination by Niu et al.
Scheme 30: Triazole linked peptidomimetics obtained from two separate MCRs and a sequential Click reaction.
Scheme 31: Copper-free synthesis of triazoles via two MCRs in one-pot.
Scheme 32: The sequential Ugi/Paal–Knorr reaction to afford pyrazoles.
Scheme 33: An intramolecular Paal–Knorr condensation provided under basic conditions pyrazolones.
Scheme 34: Similar cyclization performed under acidic conditions provided pyrazolones without the trifluoroace...
Scheme 35: The Ugi-4CR towards 2,4-disubstituted thiazoles.
Scheme 36: Solid phase approach towards thiazoles.
Scheme 37: Reaction mechanism of formation of thiazole peptidomimetics containing an additional β-lactam moiet...
Scheme 38: The synthesis of the trisubstituted thiazoles could be either performed via an Ugi reaction with pr...
Scheme 39: Performing the Ugi reaction with DMB-protected isocyanide gave access to either oxazoles or thiazol...
Scheme 40: Ugi/cyclization-approach towards 2,5-disubstituted thiazoles. The Ugi reaction was performed with d...
Scheme 41: Further derivatization of the thiazole scaffold.
Scheme 42: Three-step procedure towards the natural product bacillamide C.
Scheme 43: Ugi-4CR to oxazoles reported by Zhu and co-workers.
Scheme 44: Ugi-based synthesis of oxazole-containing peptidomimetics.
Scheme 45: TMNS3 based Ugi reaction for peptidomimics containing a tetrazole.
Scheme 46: Catalytic cycle of the enantioselective Passerini reaction towards tetrazole-based peptidomimetics.
Scheme 47: Tetrazole-based peptidomimetics via an Ugi reaction and a subsequent sigmatropic rearrangement.
Scheme 48: Resin-bound Ugi-approach towards tetrazole-based peptidomimetics.
Scheme 49: Ugi/cyclization approach towards γ/δ/ε-lactam tetrazoles.
Scheme 50: Ugi-3CR to pipecolic acid-based peptidomimetics.
Scheme 51: Staudinger–Aza-Wittig/Ugi-approach towards pipecolic acid peptidomimetics.
Figure 1: The three structural isomers of diketopiperazines. The 2,5-DKP isomer is most common.
Scheme 52: UDC-approach to obtain 2,5-DKPs, either using Armstrong’s isocyanide or via ethylglyoxalate.
Scheme 53: a) Ugi reaction in water gave either 2,5-DKP structures or spiro compounds. b) The Ugi reaction in ...
Scheme 54: Solid-phase approach towards diketopiperazines.
Scheme 55: UDAC-approach towards DKPs.
Scheme 56: The intermediate amide is activated as leaving group by acid and microwave assisted organic synthes...
Scheme 57: UDC-procedure towards active oxytocin inhibitors.
Scheme 58: An improved stereoselective MCR-approach towards the oxytocin inhibitor.
Scheme 59: The less common Ugi reaction towards DKPs, involving a Sn2-substitution.
Figure 2: Spatial similarities between a natural β-turn conformation and a DKP based β-turn mimetic [158].
Scheme 60: Ugi-based syntheses of bicyclic DKPs. The amine component is derived from a coupling between (R)-N-...
Scheme 61: Ugi-based synthesis of β-turn and γ-turn mimetics.
Figure 3: Isocyanide substituted 3,4-dihydropyridin-2-ones, dihydropyridines and the Freidinger lactams. Bio-...
Scheme 62: The mechanism of the 4-CR towards 3,4-dihydropyridine-2-ones 212.
Scheme 63: a) Multiple MCR-approach to provide DHP-peptidomimetic in two-steps. b) A one-pot 6-CR providing th...
Scheme 64: The MCR–alkylation–MCR procedure to obtain either tetrapeptoids or depsipeptides.
Scheme 65: U-3CR/cyclization employing semicarbazone as imine component gave triazine based peptidomimetics.
Scheme 66: 4CR towards triazinane-diones.
Scheme 67: The MCR–alkylation–IMCR-sequence described by our group towards triazinane dione-based peptidomimet...
Scheme 68: Ugi-4CR approaches followed by a cyclization to thiomorpholin-ones (a) and pyrrolidines (b).
Scheme 69: UDC-approach for benzodiazepinones.
Scheme 70: Ugi/Mitsunobu sequence to BDPs.
Scheme 71: A UDAC-approach to BDPs with convertible isocyanides. The corresponding amide is cleaved by microwa...
Scheme 72: microwave assisted post condensation Ugi reaction.
Scheme 73: Benzodiazepinones synthesized via the post-condensation Ugi/ Staudinger–Aza-Wittig cyclization.
Scheme 74: Two Ugi/cyclization approaches utilizing chiral carboxylic acids. Reaction (a) provided the product...
Scheme 75: The mechanism of the Gewald-3CR includes three base-catalysed steps involving first a Knoevnagel–Co...
Scheme 76: Two structural 1,4-thienodiazepine-2,5-dione isomers by U-4CR/cyclization.
Scheme 77: Tetrazole-based diazepinones by UDC-procedure.
Scheme 78: Tetrazole-based BDPs via a sequential Ugi/hydrolysis/coupling.
Scheme 79: MCR synthesis of three different tricyclic BPDs.
Scheme 80: Two similar approaches both involving an Ugi reaction and a Mitsunobu cyclization.
Scheme 81: Mitsunobu–Ugi-approach towards dihydro-1,4-benzoxazepines.
Scheme 82: Ugi reaction towards hetero-aryl fused 5-oxo-1,4-oxazepines.
Scheme 83: a) Ugi/RCM-approach towards nine-membered peptidomimetics b) Sequential peptide-coupling, deprotect...
Scheme 84: Ugi-based synthesis towards cyclic RGD-pentapeptides.
Scheme 85: Ugi/MCR-approach towards 12–15 membered macrocycles.
Scheme 86: Stereoselective Ugi/RCM approach towards 16-membered macrocycles.
Scheme 87: Passerini/RCM-sequence to 22-membered macrocycles.
Scheme 88: UDAC-approach towards 12–18-membered depsipeptides.
Figure 4: Enopeptin A with its more active derivative ADEP-4.
Scheme 89: a) The Joullié–Ugi-approach towards ADEP-4 derivatives b) Ugi-approach for the α,α-dimethylated der...
Scheme 90: Ugi–Click-strategy for 15-membered macrocyclic glyco-peptidomimetics.
Scheme 91: Ugi/Click combinations provided macrocycles containing both a triazole and an oxazole moiety.
Scheme 92: a) A solution-phase procedure towards macrocycles. b) Alternative solid-phase synthesis as was repo...
Scheme 93: Ugi/cyclization towards cyclophane based macrocycles.
Scheme 94: PADAM-strategy towards eurystatin A.
Scheme 95: PADAM-approach for cyclotheanamide.
Scheme 96: A triple MCR-approach affording RGD-pentapeptoids.
Scheme 97: Ugi-MiBs-approach towards peptoid macrocycles.
Scheme 98: Passerini-based MiB approaches towards macrocycles 345 and 346.
Scheme 99: Macrocyclic peptide formation by the use of amphoteric aziridine-based aldehydes.
Beilstein J. Org. Chem. 2014, 10, 194–208, doi:10.3762/bjoc.10.15
Graphical Abstract
Figure 1: Structures of the 4,4,8-trimethyl-17-furanylsteroid core structure I and the representative B-seco ...
Scheme 1: Retrosynthetic analysis of the B-seco limonoid framework employing a [3,3]-sigmatropic rearrangemen...
Scheme 2: Retrosynthetic analysis of the B-seco limonoid scaffold employing a Claisen rearrangement as key st...
Scheme 3: Synthesis of alcohols 19, 20 and 22. Reagents and conditions: a) CSA, 2,3-butanedione, trimethyl or...
Scheme 4: Retrosynthetic analysis of the B-seco limonoid scaffold employing an Ireland–Claisen rearrangement ...
Scheme 5: Synthesis and Ireland–Claisen rearrangement of the allyl esters 27, 28, 29 and 30. Reagents and con...
Figure 2: Conformation of rearrangement precursor 30 and possible transition state involved in the Ireland–Cl...
Scheme 6: Synthesis of model C rings 40, 41 and 42. Reagents and conditions: a) TBDPSCl, DMAP, NEt3, CH2Cl2, ...
Scheme 7: β-Substituted allyl esters tested in the Ireland–Claisen and the Carroll rearrangement.
Scheme 8: Synthesis and Ireland–Claisen rearrangement of bicyclic allyl ester precursor 66. Reagents and cond...
Figure 3: Conformations of rearrangement precursors 66 and 77 and possible transition states involved in the ...
Scheme 9: Synthesis and Ireland–Claisen rearrangement of allyl ester 70. Reagents and conditions: a) DIPEA, M...
Scheme 10: Synthesis and Ireland–Claisen rearrangement of allyl ester 72. Reagents and conditions: a) TIPSOTf,...
Scheme 11: Synthesis of the C14-epi and C14/C9-epi B-seco limonoid scaffolds 78 and 79. Reagents and condition...
Scheme 12: Synthesis of fully functionalized A ring 87. Reagents and conditions: a) HO(CH2)2OH, THF, Pd/C, H2,...
Scheme 13: and Attempted Ireland–Claisen rearrangement of allyl ester 88. R1 = MOM, R2 = CO2H.
Scheme 14: Synthesis and attempted Ireland–Claisen rearrangement of allyl ester 93. Reagents and conditions: a...
Scheme 15: Allyl esters tested in the Ireland–Claisen rearrangement.
Beilstein J. Org. Chem. 2014, 10, 127–133, doi:10.3762/bjoc.10.9
Graphical Abstract
Figure 1: Bisamides as building blocks for flavaglins.
Figure 2: (+)-Grandiamide D, gigantamide A and dasyclamide.
Scheme 1: Retrosynthetic analysis: A unified synthetic approach for the synthesis of grandiamide D, dasyclami...
Scheme 2: Preparation of N-(4-aminobutyl)cinnamamide.
Scheme 3: Synthesis of (±)-grandiamide D.
Scheme 4: Asymmetric synthesis of natural (+)-grandiamide D.
Scheme 5: Various approaches for the synthesis of (E)-N-(4-cinnamamidobutyl)-4-((4-methoxybenzyl)oxy)-2-methy...
Scheme 6: Synthesis of dasyclamide.
Beilstein J. Org. Chem. 2014, 10, 12–17, doi:10.3762/bjoc.10.3
Graphical Abstract
Scheme 1: Azetidine formation from the interaction of imines with isocyanides.
Scheme 2: Reaction conditions.
Figure 1: X-ray diffraction analysis of azetidine 3a.
Scheme 3: Stepwise mechanism for the formation of azetidine 3a.
Scheme 4: Manifold reaction mechanism.
Beilstein J. Org. Chem. 2013, 9, 2821–2833, doi:10.3762/bjoc.9.317
Graphical Abstract
Figure 1: Unique structural features of (−)-isosteviol.
Figure 2: Triphenylene ketal based on (−)-isosteviol.
Figure 3: Structural features of triptycene derivatives.
Scheme 1: Functionalization of triphenylene ketal 2a.
Figure 4: Hexaammoniumtriptycene hexachloride 4 and 15-oxo-derivatives 5a–c of (–)-isosteviol.
Scheme 2: Quinoxalines based on diketone 5b.
Scheme 3: Condensation of 5b with hexaammoniumtriptycene hexachloride.
Figure 5: Molecular modelling structures (Spartan ’08 V1.0.0) of (a) all-syn-8 and (b) anti,anti,syn-8.
Scheme 4: Synthesis of nitrobenzylic ester derivatives 10 and 11, starting from (−)-isosteviol 1.
Scheme 5: Condensation of the nitrobenzyl esters 10 and 11 with hexaammoniumtriptycene hexachloride 4.
Scheme 6: Hydrogenolysis to tricarboxylic acid all-syn-16.
Scheme 7: Alkylation of all-syn-16 renders terminal alkene all-syn-17.
Figure 6: (a) Top view on the molecular structure of all-syn-17 with the terminal alkene fragments labelled i...
Scheme 8: Alkylation of (−)-isosteviol diketone 9 with 5-bromo-1-pentene.
Scheme 9: Direct synthesis of alkylated triptycene 17 by condensation of 18 with hexaammoniumtriptycene hexac...
Scheme 10: Olefin metathesis of all-syn-17.
Figure 7: Extracts of the 13C NMR spectra of starting material and product.
Figure 8: Molecular modelling structure (MacroModel 9.3.5) of collapsed 19, (a) top view; (b) side view.
Figure 9: Screening of aromatic analytes with affinity materials 3, 7, 8, 17 and 19.
Figure 10: Primary data of anti,anti,syn-8 and a [3 + 2] cage compound (increasing pseudocumene concentrations...
Figure 11: Screening of protic analytes with affinity materials 3, 8, 14 and 15.
Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265
Graphical Abstract
Scheme 1: Scaled industrial processes for the synthesis of simple pyridines.
Scheme 2: Synthesis of nicotinic acid from 2-methyl-5-ethylpyridine (1.11).
Scheme 3: Synthesis of 3-picoline and nicotinic acid.
Scheme 4: Synthesis of 3-picoline from 2-methylglutarodinitrile 1.19.
Scheme 5: Picoline-based synthesis of clarinex (no yields reported).
Scheme 6: Mode of action of proton-pump inhibitors and structures of the API’s.
Scheme 7: Hantzsch-like route towards the pyridine rings in common proton pump inhibitors.
Figure 1: Structures of rosiglitazone (1.40) and pioglitazone (1.41).
Scheme 8: Synthesis of rosiglitazone.
Scheme 9: Syntheses of 2-pyridones.
Scheme 10: Synthesis and mechanism of 2-pyrone from malic acid.
Scheme 11: Polymer-assisted synthesis of rosiglitazone.
Scheme 12: Synthesis of pioglitazone.
Scheme 13: Meerwein arylation reaction towards pioglitazone.
Scheme 14: Route towards pioglitazone utilising tyrosine.
Scheme 15: Route towards pioglitazone via Darzens ester formation.
Scheme 16: Syntheses of the thiazolidinedione moiety.
Scheme 17: Synthesis of etoricoxib utilising Negishi and Stille cross-coupling reactions.
Scheme 18: Synthesis of etoricoxib via vinamidinium condensation.
Figure 2: Structures of nalidixic acid, levofloxacin and moxifloxacin.
Scheme 19: Synthesis of moxifloxacin.
Scheme 20: Synthesis of (S,S)-2,8-diazabicyclo[4.3.0]nonane 1.105.
Scheme 21: Synthesis of levofloxacin.
Scheme 22: Alternative approach to the levofloxacin core 1.125.
Figure 3: Structures of nifedipine, amlodipine and clevidipine.
Scheme 23: Mg3N2-mediated synthesis of nifedipine.
Scheme 24: Synthesis of rac-amlodipine as besylate salt.
Scheme 25: Aza Diels–Alder approach towards amlodipine.
Scheme 26: Routes towards clevidipine.
Figure 4: Examples of piperidine containing drugs.
Figure 5: Discovery of tiagabine based on early leads.
Scheme 27: Synthetic sequences to tiagabine.
Figure 6: Structures of solifenacin (2.57) and muscarine (2.58).
Scheme 28: Enantioselective synthesis of solifenacin.
Figure 7: Structures of DPP-4 inhibitors of the gliptin-type.
Scheme 29: Formation of inactive diketopiperazines from cis-rotameric precursors.
Figure 8: Co-crystal structure of carmegliptin bound in the human DPP-4 active site (PDB 3kwf).
Scheme 30: Improved route to carmegliptin.
Figure 9: Structures of lamivudine and zidovudine.
Scheme 31: Typical routes accessing uracil, thymine and cytosine.
Scheme 32: Coupling between pyrimidones and riboses via the Vorbrüggen nucleosidation.
Scheme 33: Synthesis of lamivudine.
Scheme 34: Synthesis of raltegravir.
Scheme 35: Mechanistic studies on the formation of 3.22.
Figure 10: Structures of selected pyrimidine containing drugs.
Scheme 36: General preparation of pyrimidines and dihydropyrimidones.
Scheme 37: Synthesis of imatinib.
Scheme 38: Flow synthesis of imatinib.
Scheme 39: Syntheses of erlotinib.
Scheme 40: Synthesis of erlotinib proceeding via Dimroth rearrangement.
Scheme 41: Synthesis of lapatinib.
Scheme 42: Synthesis of rosuvastatin.
Scheme 43: Alternative preparation of the key aldehyde towards rosuvastatin.
Figure 11: Structure comparison between nicotinic acetylcholine receptor agonists.
Scheme 44: Syntheses of varenicline and its key building block 4.5.
Scheme 45: Synthetic access to eszopiclone and brimonidine via quinoxaline intermediates.
Figure 12: Bortezomib bound in an active site of the yeast 20S proteasome ([114], pdb 2F16).
Scheme 46: Asymmetric synthesis of bortezomib.
Figure 13: Structures of some prominent piperazine containing drugs.
Figure 14: Structural comparison between the core of aplaviroc (4.35) and a type-1 β-turn (4.36).
Scheme 47: Examplary synthesis of an aplaviroc analogue via the Ugi-MCR.
Scheme 48: Syntheses of azelastine (5.1).
Figure 15: Structures of captopril, enalapril and cilazapril.
Scheme 49: Synthesis of cilazapril.
Figure 16: Structures of lamotrigine, ceftriaxone and azapropazone.
Scheme 50: Synthesis of lamotrigine.
Scheme 51: Alternative synthesis of lamotrigine (no yields reported).
Figure 17: Structural comparison between imiquimod and the related adenosine nucleoside.
Scheme 52: Conventional synthesis of imiquimod (no yields reported).
Scheme 53: Synthesis of imiquimod.
Scheme 54: Synthesis of imiquimod via tetrazole formation (not all yields reported).
Figure 18: Structures of various anti HIV-medications.
Scheme 55: Synthesis of abacavir.
Figure 19: Structures of diazepam compared to modern replacements.
Scheme 56: Synthesis of ocinaplon.
Scheme 57: Access to zaleplon and indiplon.
Scheme 58: Different routes towards the required N-methylpyrazole 6.65 of sildenafil.
Scheme 59: Polymer-supported reagents in the synthesis of key aminopyrazole 6.72.
Scheme 60: Early synthetic route to sildenafil.
Scheme 61: Convergent preparations of sildenafil.
Figure 20: Comparison of the structures of sildenafil, tadalafil and vardenafil.
Scheme 62: Short route to imidazotriazinones.
Scheme 63: Alternative route towards vardenafils core imidazotriazinone (6.95).
Scheme 64: Bayer’s approach to the vardenafil core.
Scheme 65: Large scale synthesis of vardenafil.
Scheme 66: Mode of action of temozolomide (6.105) as methylating agent.
Scheme 67: Different routes to temozolomide.
Scheme 68: Safer route towards temozolomide.
Figure 21: Some unreported heterocyclic scaffolds in top market drugs.
Beilstein J. Org. Chem. 2013, 9, 2233–2241, doi:10.3762/bjoc.9.262
Graphical Abstract
Figure 1: Selected biocatalytic allylic and benzylic oxidations with the lyophilisate of Pleurotus sapidus (P...
Scheme 1: Biocatalytic allylic oxidation of theaspirane (1) with lyophilisates of PSA. Only one enantiomer of...
Figure 2: Selected bioactive terpenoids based on spiroether backbones [38,39].
Scheme 2: Intramolecular silyl modified Sakurai reaction to spiroethers 7–9 and 11–13.
Scheme 3: Biocatalytic allylic oxidation of spiroethers 7, 8, 11 and 12 with the lyophilisate of PSA. Convers...
Figure 3: Bond-dissociation enthalpies for three allylic C–H bonds in 11. Double stabilization of the radical...
Scheme 4: Improved 3-step synthesis of vitispirane (23) from theaspirane (1). Only one enantiomer of racemic ...
Scheme 5: Oxidation of vitispirane (23) with PSA gave enone 24 and two diastereomeric allyl alcohols 26a and ...
Beilstein J. Org. Chem. 2013, 9, 2048–2078, doi:10.3762/bjoc.9.243
Graphical Abstract
Figure 1: a) Structural features and b) selected examples of non-natural congeners.
Scheme 1: Synthesis of isoindole 18.
Scheme 2: Staining amines with 1,4-diketone 19 (R = H).
Figure 2: Representative members of the indolocarbazole alkaloid family.
Figure 3: Staurosporine (26) bound to the adenosine-binding pocket [19] (from pdb1stc).
Figure 4: Structure of imatinib (34) and midostaurin (35).
Scheme 3: Biosynthesis of staurosporine (26).
Scheme 4: Wood’s synthesis of K-252a via the common intermediate 48.
Scheme 5: Synthesis of 26, 27, 49 and 50 diverging from the common intermediate 48.
Figure 5: Selected members of the cytochalasan alkaloid family.
Scheme 6: Biosynthesis of chaetoglobosin A (57) [56].
Scheme 7: Synthesis of cytochalasin D (70) by Thomas [63].
Scheme 8: Synthesis of L-696,474 (78).
Scheme 9: Synthesis of aldehyde 85 (R = TBDPS).
Scheme 10: Synthesis of (+)-aspergillin PZ (79) by Tanis.
Figure 6: Representative Berberis alkaloids.
Scheme 11: Proposed biosynthetic pathway to chilenine (93).
Scheme 12: Synthesis of magallanesine (97) by Danishefsky [84].
Scheme 13: Kurihara’s synthesis of magallanesine (85).
Scheme 14: Proposed biosynthesis of 113, 117 and 125.
Scheme 15: DNA lesion caused by aristolochic acid I (117) [102].
Scheme 16: Snieckus’ synthesis of piperolactam C (131).
Scheme 17: Synthesis of aristolactam BII (104).
Figure 7: Representative cularine alkaloids.
Scheme 18: Proposed biosynthesis of 136.
Scheme 19: The syntheses of 136 and 137 reported by Castedo and Suau.
Scheme 20: Synthesis of 136 by Couture.
Figure 8: Representative isoindolinone meroterpenoids.
Scheme 21: Postulated biosynthetic pathway for the formation of 156 (adopted from George) [143].
Scheme 22: Synthesis of stachyflin (156) by Katoh [144].
Figure 9: Selected examples of spirodihydrobenzofuranlactams.
Scheme 23: Synthesis of stachybotrylactam I (157).
Scheme 24: Synthesis of pestalachloride A (193) by Schmalz.
Scheme 25: Proposed mechanism for the BF3-catalyzed metal-free carbonyl–olefin metathesis [149].
Scheme 26: Preparation of the isoindoline core of muironolide A (204).
Scheme 27: Proposed biosynthesis of 208.
Scheme 28: Model for the biosynthesis of 215 and 217.
Scheme 29: Synthesis of lactonamycin (215) and lactonamycin Z (217).
Figure 10: Hetisine alkaloids 225–228.
Scheme 30: Biosynthetic proposal for the formation of the hetisine core [167].
Scheme 31: Synthesis of nominine (225).
Beilstein J. Org. Chem. 2013, 9, 1826–1836, doi:10.3762/bjoc.9.213
Graphical Abstract
Figure 1: Structures of the 2,3-dihydroxycholestane isomers studied in this work.
Figure 2: 3D plots for LMOG 1 and solvent parameters of the tested solvents a) Hansen solubility parameters (δ...
Figure 3: Tg-vs-concentration plots for gels of 1.
Figure 4: SEM images of xerogels from a,b) dichloromethane, and c,d) from dioxane.
Figure 5: Powder X-ray diffraction pattern of the xerogels of 1 from a) n-hexane and b) dichloromethane.
Figure 6: Self-assembly models proposed for LMOG 1, only the left handed helix is shown, head to head hydroge...
Figure 7: SEM images of nanostructured silica obtained from gels of LMOG 1 under the following conditions: 0....
Beilstein J. Org. Chem. 2013, 9, 1677–1695, doi:10.3762/bjoc.9.192
Graphical Abstract
Figure 1: The catalyzed enantioselective desymmetrization.
Figure 2: Cinchona alkaloid-derived catalysts OC-1 to OC-11.
Scheme 1: The enantioselective desymmetrization of meso-aziridines in the presence of selected Cinchona alkal...
Figure 3: Cinchona alkaloid-derived catalysts OC-12 to OC-19.
Scheme 2: The enantioselective ring-opening of aziridines in the presence of OC-16.
Scheme 3: OC-16 catalyzed enantioselective ring-opening of aziridines.
Figure 4: The chiral phosphoric acids catalysts OC-20 and OC-21.
Scheme 4: OC-20 and OC-21 catalyzed enantioselective desymmetrization of meso-aziridines.
Figure 5: The proposed mechanism for chiral phosphorous acid-induced enantioselctive desymmetrization of meso...
Scheme 5: OC-21 catalyzed enantioselective desymmetrization of meso-aziridines by Me3SiSPh.
Scheme 6: OC-21 catalyzed the enantioselective desymmetrization of meso-aziridines by Me3SiSePh/PhSeH.
Figure 6: L-Proline and its derivatives OC-22 to OC-27.
Scheme 7: OC-23 catalyzed enantioselective desymmetrization of meso-aziridines.
Figure 7: Proposed bifunctional mode of action of OC-23.
Figure 8: The chiral thioureas OC-28 to OC-44 for the desymmetrization of meso-aziridines.
Scheme 8: Desymmetrization of meso-aziridines with OC-41.
Figure 9: The chiral guanidines (OC-45 to OC-48).
Scheme 9: OC-46 catalyzed desymmetrization of meso-aziridines by arylthiols.
Scheme 10: Desymmetrization of cis-aziridine-2,3-dicarboxylate.
Figure 10: The proposed activation mode of OC-46.
Scheme 11: The enantioselective desymmetrization of meso-aziridines by amine/CS2 in the presence of OC-46.
Figure 11: The chiral 1,2,3-triazolium chlorides OC-49 to OC-55.
Scheme 12: The enantioselective desymmetrization of meso-aziridines by Me3SiX (X = Cl or Br) in the presence o...
Figure 12: Early organocatalysts for enantioselective desymmetrization of meso-epoxides.
Scheme 13: Attempts of enantioselective desymmetrization of meso-epoxides in the presence of OC-58 or OC-60.
Scheme 14: The enantioselective desymmetrization of a meso-epoxide containing one P atom.
Figure 13: Some chiral phosphoramide and chiral phosphine oxides.
Scheme 15: OC-62 catalyzed enantioselective desymmetrization of meso-epoxides by SiCl4.
Figure 14: The proposed mechanism of the chiral HMPA-catalyzed desymmetrization of meso-epoxides.
Scheme 16: The enantioselective desymmetrization of meso-epoxides in the presence of OC-63.
Figure 15: The Chiral phosphine oxides (OC-70 to OC-77) based on an allene backbone.
Scheme 17: OC-73 catalyzed enantioselective desymmetrization of meso-epoxides by SiCl4.
Figure 16: Chiral pyridine N-oxides used in enantioselective desymmetrization of meso-epoxides.
Scheme 18: Catalyzed enantioselective desymmetrization of meso-epoxides in the presence of OC-80 or OC-82.
Figure 17: Chiral pyridine N-oxides OC-85 to OC-94.
Scheme 19: Enantioselective desymmetrization of cis-stilbene oxide by using OC-85 to OC-92 as catalysts.
Figure 18: A novel family of helical chiral pyridine N-oxides OC-95 to OC-97.
Scheme 20: Desymmetrization of meso-epoxides catalyzed by OC-95 to OC-97.
Scheme 21: OC-98 catalyzed enantioselective desymmetrization of meso-epoxides by SiCl4.
Beilstein J. Org. Chem. 2013, 9, 1352–1382, doi:10.3762/bjoc.9.153
Graphical Abstract
Figure 1: Qualitative orbital diagram for a d8 metal in ML4 square-planar and ML3 T-shaped complexes.
Figure 2: Walsh diagram for the d-block of a d8 ML3 complex upon bending of one L–M–L angle.
Figure 3: Neutral Y-shaped Pt complex Y1 [15]. Angles are given in degrees.
Figure 4: General classification of T-shaped Pt(II) structures according to the fourth coordination site.
Figure 5: Hydride, boryl and borylene true T-shaped Pt(II) complexes.
Figure 6: NHC-based true T-shaped Pt(II) complexes.
Figure 7: Phosphine-based agostic T-shaped Pt(II) complexes. Compounds in brackets correspond with hydrido–al...
Figure 8: Phenylpyridine and NHC-based agostic T-shaped Pt(II) complexes.
Figure 9: Counteranion coordination in T-shaped Pt(II) complexes.
Figure 10: Phosphine-based solvento Pt(II) complexes.
Figure 11: Nitrogen-based solvento Pt(II) complexes.
Figure 12: Pincer-based solvento Pt(II) complexes.
Figure 13: Structure of the QM/MM optimized cisplatin–protein adduct [94].
Figure 14: NMR coupling constants used for the characterization of three-coordinate Pt(II) species.
Figure 15: The chemical formula of the complexes discussed in Table 2.
Scheme 1: Halogen abstraction from 1.
Scheme 2: Halogen abstraction from 2 forming the dicationic complex T3 [22].
Scheme 3: Hydrogenation of complexes A5a and A5b [39].
Scheme 4: Hydrogenation of complexes 3 and A5c [40].
Scheme 5: Intermolecular C–H bond activation from T5a [28].
Scheme 6: Protonation of complexes 4 [35,36].
Scheme 7: Cyclometalation of 5 [43].
Scheme 8: Protonation of 6.
Scheme 9: Reductive elimination of ethane from 7.
Scheme 10: Reductive elimination of methane from six-coordinate Pt(IV) complexes.
Scheme 11: Proposed dissociative mechanism for the fluxional motion of dmphen in [Pt(Me)(dmphen)(PR3)]+ comple...
Figure 16: Feasible interactions for unsaturated intermediates 11b (left) and 12b (right) during fluxional mot...
Scheme 12: Halogen abstraction from 13a,b and subsequent cyclometalation to yield complexes A5a,b [39].
Scheme 13: Proposed mechanism for the acid-catalyzed cyclometalation of 14 via intermediate 15 [41].
Scheme 14: Proposed mechanism for the formation of 19 [102].
Scheme 15: Cyclometalation of 20 via thioether dissociation [117].
Figure 17: Gibbs energy profile (in chloroform solvent) for the cyclometalation of 23 [120].
Scheme 16: Coordination of tmtu to 29 and subsequent C–H bond activation via three-coordinate species 31 and 32...
Scheme 17: Cyclometalation process of NHC-based Pt(II) complexes [28,44].
Scheme 18: Cyclometalation process of complex A9 [43].
Scheme 19: “Rollover” reaction of 38 and subsequent oligomerization [123].
Scheme 20: Proposed mechanism for the formation of cyclometalated species 44 [124].
Scheme 21: Self-assembling process of 45 by “rollover” reaction [126].
Scheme 22: “Rollover” reaction of A9. Energies (solvent) in kcal mol−1 [127].
Scheme 23: Proposed mechanisms for the “rollover” cyclometalation of 52 in gas-phase ion-molecule reactions [128].
Scheme 24: β-H elimination and 1,2-insertion equilibrium involving A1d and the subsequent generation of 57 [35].
Scheme 25: Proposed mechanism for thermolysis of 7b and 7c in benzene-d6 and cyclohexane-d12 solvents [101].
Scheme 26: β-H elimination process of A11a [28].
Scheme 27: Intermolecular C–H bond activation from 62 [95].
Scheme 28: Reductive elimination of methane from 65 followed by CD3CN coordination or C–D bond-activation proc...
Figure 18: DFT-optimized structures describing the κ2 (69, left) and κ3 (69’, right) coordination modes of [Pt...
Scheme 29: Intermolecular arene C–H bond activation from NHC-based complexes [28].
Figure 19: Energy profiles (in benzene solvent) for the benzene C–H bond activation from A11a, A11b, T5a and T...
Scheme 30: Intermolecular arene C–H bond activation from PNP-based complex 71 [12].
Scheme 31: Intermolecular C–H bond-activation by gas-phase ion-molecule reactions of 74 [7,142].
Scheme 32: Dihydrogen activation through complexes A5a, A5b [39], A5c [40] and S1a [54].
Scheme 33: Dihydrogen activation through complexes A7 and 16 [41]. For a: see Scheme 13.
Scheme 34: Br2 and I2 bond activations through complexes A11a and T5a [143].
Scheme 35: Detection and isolation of the Pt(III) complex 81a [143].
Scheme 36: Cl2 bond activation through complexes 82 and 83 [144].
Scheme 37: cis–trans Isomerization mechanism of the solvento Pt(II) complexes S5 [2,61].
Figure 20: Energy profiles for the isomerization of complexes [Pt(R)(PMe3)2(NCMe)]+ where R means Me (85a, red...
Figure 21: DFT-optimized structure of intermediate 86 [62]. Bond distances in angstrom and angles in degrees.
Scheme 38: Proposed dissociative ligand-substitution mechanism of cis-[Pt(R)2S2] complexes (87) [117].
Scheme 39: Proposed mechanisms for the ligand substitution of the dinuclear species 91 [146].
Beilstein J. Org. Chem. 2013, 9, 1319–1325, doi:10.3762/bjoc.9.148
Graphical Abstract
Scheme 1: Formation of (Z)-chloro-exo-methyleneketals.
Scheme 2: Mechanism of formation of (Z)-chloro-exo-methylenetetrahydrofurans.
Scheme 3: Stepwise formation of (Z)-chloro-exo-methylenetetrahydrofurans.
Scheme 4: Optimized protocols to form (Z)-chloro-exo-methylenetetrahydrofurans.
Scheme 5: Hydration of (Z)-chloro-exo-methylenetetrahydrofurans.
Scheme 6: Formation of dioxanes.
Figure 1: X-ray diffraction analysis of dioxanes 35 and 36.
Scheme 7: Formation of a new spirocyclic dimer.
Scheme 8: Mechanism leading to dioxanes and spirocycles.
Scheme 9: (S,S)-syn and (S,R)-syn approaches.
Scheme 10: Formation of a bridged dimer and a triene.
Figure 2: X-ray diffraction analysis of two new dimers.
Scheme 11: Mechanism leading to bridged and dienic dimers.
Beilstein J. Org. Chem. 2013, 9, 991–1001, doi:10.3762/bjoc.9.114
Graphical Abstract
Scheme 1: Synthesis of hexaethyl dialkylaminomethylidynetrisphosphonates 1 from dichloromethylene dialkylammo...
Scheme 2: Synthesis and some transformations of trisphosphonate 2.
Scheme 3: Attempt to synthesize trisphosphonates by the combination of Arbuzov reaction and dialkyl phosphite...
Scheme 4: Synthesis of hexaethylmethylidynetrisphosphonate 6 via phosphinylation of tetraethyl methylenebisph...
Scheme 5: Synthetic approach to methylidynetrisphosphonate ester 9.
Scheme 6: Synthesis of alkylidyne-1,1,1-trisphosphonate esters 12.
Scheme 7: Two-step one-pot synthesis of propargyl-substituted trisphosphonate 15.
Scheme 8: Synthetic route to trisphosphonate 18 via 7,7-bisphosphonyl-3,5-di-tert-butylquinone methide 17.
Scheme 9: Synthesis of trisphosphonate 18 starting from 2,6-di-tert-butyl-4-(dichloromethyl)phenol.
Scheme 10: Synthesis of triphosphorus derivatives 20 via quinone methides 17 and 19.
Scheme 11: Unexpected phosphonylation of the aromatic nucleus in reactions of quinone methides 19 and 21.
Scheme 12: Multistep synthesis of trisphosphonate 18 starting from quinone methide 25.
Scheme 13: Synthesis of hexaethyl methylidynetrisphosphonate (6) via metal-carbenoid-mediated P–H insertion re...
Scheme 14: Reaction between tert-butylphosphaethyne and diethyl phosphite in the presence of sodium metal.
Scheme 15: Cross metathesis of trisphosphonates 12 with 2-methyl-2-butene and the Grubbs second-generation cat...
Scheme 16: Hydroboration–oxidation of trisphosphonates 12b,e.
Scheme 17: Reaction of 3-butyn-1-ylidenetrisphosphonate 15 with benzyl azide.
Scheme 18: The use of the transsilylation reaction for the synthesis of trisphosphonate salts 37.
Scheme 19: Synthesis of the sodium salt of the acid-labile trisphosphonic acid 38.
Scheme 20: Acidic hydrolysis of trisphosphonate ester 1a.
Scheme 21: Methylation of trisphosphonate 1a.
Scheme 22: Synthesis of the free methylidynetrisphosphonic acid via trisphosphonate salt 38.
Scheme 23: Synthesis of halomethylidynetrisphosphonate salts 43 and 44 by modified Gross’s procedure.
Scheme 24: Synthesis of trisphosphonate modified nucleotides. Reagents: i, 5'-O-tosyl adenosine, MeCN; ii, AMP...
Figure 1: Bond angles and bond distances in pyrophosphate, methylene-1,1-bisphosphonate and fluoromethylidyne...
Beilstein J. Org. Chem. 2013, 9, 81–88, doi:10.3762/bjoc.9.11
Graphical Abstract
Figure 1: FDA approved HDAC inhibitors for the treatment of CTCL.
Scheme 1: SAR of psammaplin A against zinc-dependant HDACs. Adapted from Baud et al. [20].
Scheme 2: Synthesis of 7–9. Conditions: (i) HCl·H2NOMe, pyridine, rt, 12 h; (ii) EDC, NHS, dioxane, rt, 3 h; ...
Scheme 3: Top: Generation of the fluorescent adduct 11 after reaction of probe 10 with thiols. Bottom left: F...
Figure 2: rHDAC1 was incubated with a predetermined IC50 concentration of 7 (left) and 9 (right) for 1–60 min...
Beilstein J. Org. Chem. 2012, 8, 1884–1889, doi:10.3762/bjoc.8.217
Graphical Abstract
Figure 1: Structures of selaginellins from S. tamariscina.
Figure 2: Key HMBC correlations of compound 1.