Search results
Search for "diimine intermediate" in Full Text gives 3 result(s) in Beilstein Journal of Organic Chemistry.
Recent advances in organocatalytic atroposelective reactions
- Henrich Szabados and
- Radovan Šebesta
Beilstein J. Org. Chem. 2025, 21, 55–121, doi:10.3762/bjoc.21.6
- of the developed protocol was demonstrated on a gram-scale reaction, where the corresponding product 200 was obtained with an acceptable decrease of yield and enantioselectivity (65%, 94% ee). Mechanistically, a chemo- and regioselective nucleophilic addition followed by dehydration leads to diimine
- intermediate Int-53. Control experiments confirmed that this structure could undergo successive reduction and oxidation through intermediate Int-54 to give benzylimine intermediate Int-55. Alternatively, a direct [1,5]-H migration of Int-53 also leads to Int-55. The stereoselectivity of the product is
Graphical Abstract
Scheme 1: Formation of axially chiral styrenes 3 via iminium activation.
Scheme 2: Synthesis of axially chiral 2-arylquinolines 6.
Scheme 3: Atroposelective intramolecular (4 + 2) annulation leading to aryl-substituted indolines.
Scheme 4: Atroposelective formation of biaryl via twofold aldol condensation.
Scheme 5: Strategy towards diastereodivergent formation of axially chiral oligonaphthylenes.
Scheme 6: Atroposelective formation of chiral biaryls based on a Michael/Henry domino reaction.
Scheme 7: Organocatalytic Michael/aldol cascade followed by oxidative aromatization.
Scheme 8: Atroposelective formation of C(sp2)–C(sp3) axially chiral compounds.
Scheme 9: NHC-catalyzed synthesis of axially chiral styrenes 26.
Scheme 10: NHC-catalyzed synthesis of biaxial chiral pyranones.
Scheme 11: Formation of bridged biaryls with eight-membered lactones.
Scheme 12: The NHC-catalyzed (3 + 2) annulation of urazoles 37 and ynals 36.
Scheme 13: NHC-catalyzed synthesis of axially chiral 4‑aryl α‑carbolines 41.
Scheme 14: NHC-catalyzed construction of N–N-axially chiral pyrroles and indoles.
Scheme 15: NHC-catalyzed oxidative Michael–aldol cascade.
Scheme 16: NHC-catalyzed (4 + 2) annulation for the synthesis of benzothiophene-fused biaryls.
Scheme 17: NHC-catalyzed desymmetrization of N-aryl maleimides.
Scheme 18: NHC-catalyzed deracemization of biaryl hydroxy aldehydes 55a–k into axially chiral benzonitriles 56a...
Scheme 19: NHC-catalyzed desymmetrization of 2-aryloxyisophthalaldehydes.
Scheme 20: NHC-catalyzed DKR of 2-arylbenzaldehydes 62.
Scheme 21: Atroposelective biaryl amination.
Scheme 22: CPA-catalyzed atroposelective amination of 2-anilinonaphthalenes.
Scheme 23: Atroposelective DKR of naphthylindoles.
Scheme 24: CPA-catalyzed kinetic resolution of binaphthylamines.
Scheme 25: Atroposelective amination of aromatic amines with diazodicarboxylates.
Scheme 26: Atroposelective Friedländer heteroannulation.
Scheme 27: CPA-catalyzed formation of axially chiral 4-arylquinolines.
Scheme 28: CPA-catalyzed Friedländer reaction of arylketones with cyclohexanones.
Scheme 29: CPA-catalyzed atroposelective Povarov reaction.
Scheme 30: Atroposelective CPA-catalyzed Povarov reaction.
Scheme 31: Paal–Knorr formation of axially chiral N-pyrrolylindoles and N-pyrrolylpyrroles.
Scheme 32: Atroposelective Paal–Knorr reaction leading to N-pyrrolylpyrroles.
Scheme 33: Atroposelective Pictet–Spengler reaction of N-arylindoles with aldehydes.
Scheme 34: Atroposelective Pictet–Spengler reaction leading to tetrahydroisoquinolin-8-ylanilines.
Scheme 35: Atroposelective formation of arylindoles.
Scheme 36: CPA-catalyzed arylation of naphthoquinones with indolizines.
Scheme 37: Atroposelective reaction of o-naphthoquinones.
Scheme 38: CPA-catalyzed formation of axially chiral arylquinones.
Scheme 39: CPA-catalyzed axially chiral N-arylquinones.
Scheme 40: Atroposelective additions of bisindoles to isatin-based 3-indolylmethanols.
Scheme 41: CPA-catalyzed synthesis of axially chiral arylindolylindolinones.
Scheme 42: CPA-catalyzed reaction between bisindoles and ninhydrin-derived 3-indoylmethanols.
Scheme 43: Atroposelective reaction of bisindoles and isatin-derived imines.
Scheme 44: CPA-catalyzed formation of axially chiral bisindoles.
Scheme 45: Atroposelective reaction of 2-naphthols with alkynylhydroxyisoindolinones.
Scheme 46: CPA-catalyzed reaction of indolylnaphthols with propargylic alcohols.
Scheme 47: Atroposelective formation of indolylpyrroloindoles.
Scheme 48: Atroposelective reaction of indolylnaphthalenes with alkynylnaphthols.
Scheme 49: CPA-catalyzed addition of naphthols to alkynyl-2-naphthols and 2-naphthylamines.
Scheme 50: CPA-catalyzed formation of axially chiral aryl-alkene-indoles.
Scheme 51: CPA-catalyzed formation of axially chiral styrenes.
Scheme 52: Atroposelective formation of alkenylindoles.
Scheme 53: Atroposelective formation of axially chiral arylquinolines.
Scheme 54: Atroposelective (3 + 2) cycloaddition of alkynylindoles with azonaphthalenes.
Scheme 55: CPA-catalyzed formation of axially chiral 3-(1H-benzo[d]imidazol-2-yl)quinolines.
Scheme 56: Atroposelective cyclization of 3-(arylethynyl)-1H-indoles.
Scheme 57: Atroposelective three-component heteroannulation.
Scheme 58: CPA-catalyzed formation of arylbenzimidazols.
Scheme 59: CPA-catalyzed reaction of N-naphthylglycine esters with nitrosobenzenes.
Scheme 60: CPA-catalyzed formation of axially chiral N-arylbenzimidazoles.
Scheme 61: CPA-catalyzed formation of axially chiral arylbenzoindoles.
Scheme 62: CPA-catalyzed formation of pyrrolylnaphthalenes.
Scheme 63: CPA-catalyzed addition of naphthols and indoles to nitronaphthalenes.
Scheme 64: Atroposelective reaction of heterobiaryl aldehydes and aminobenzamides.
Scheme 65: Atroposelective cyclization forming N-arylquinolones.
Scheme 66: Atroposelective formation of 9H-carbazol-9-ylnaphthalenes and 1H-indol-1-ylnaphthalene.
Scheme 67: CPA-catalyzed formation of pyrazolylnaphthalenes.
Scheme 68: Atroposelective addition of diazodicarboxamides to azaborinephenols.
Scheme 69: Catalytic formation of axially chiral arylpyrroles.
Scheme 70: Atroposelective coupling of 1-azonaphthalenes with 2-naphthols.
Scheme 71: CPA-catalyzed formation of axially chiral oxindole-based styrenes.
Scheme 72: Atroposelective electrophilic bromination of aminonaphthoquinones.
Scheme 73: Atroposelective bromination of dienes.
Scheme 74: CPA-catalyzed formation of axially chiral 5-arylpyrimidines.
Scheme 75: Atroposelective hydrolysis of biaryloxazepines.
Scheme 76: Atroposelective opening of dinaphthosiloles.
Scheme 77: Atroposelective reduction of naphthylenals.
Scheme 78: Atroposelective allylic substitution with 2-naphthols.
Scheme 79: Atroposelective allylic alkylation with phosphinamides.
Scheme 80: Atroposelective allylic substitution with aminopyrroles.
Scheme 81: Atroposelective allylic substitution with aromatic sulfinamides.
Scheme 82: Atroposelective sulfonylation of naphthylynones.
Scheme 83: Squaramide-catalyzed reaction of alkynyl-2-naphthols with 5H-oxazolones.
Scheme 84: Formation of axially chiral styrenes via sulfonylative opening of cyclopropanols.
Scheme 85: Atroposelective organo-photocatalyzed sulfonylation of alkynyl-2-naphthols.
Scheme 86: Thiourea-catalyzed atroposelective cyclization of alkynylnaphthols.
Scheme 87: Squaramide-catalyzed formation of axially chiral naphthylisothiazoles.
Scheme 88: Atroposelective iodo-cyclization catalyzed by squaramide C69.
Scheme 89: Squaramide-catalyzed formation of axially chiral oligoarenes.
Scheme 90: Atroposelective ring-opening of cyclic N-sulfonylamides.
Scheme 91: Thiourea-catalyzed kinetic resolution of naphthylpyrroles.
Scheme 92: Atroposelective ring-opening of arylindole lactams.
Scheme 93: Atroposelective reaction of 1-naphthyl-2-tetralones and diarylphosphine oxides.
Scheme 94: Atroposelective reaction of iminoquinones with indoles.
Scheme 95: Kinetic resolution of binaphthylalcohols.
Scheme 96: DKR of hydroxynaphthylamides.
Scheme 97: Atroposelective N-alkylation with phase-transfer catalyst C75.
Scheme 98: Atroposelective allylic substitution via kinetic resolution of biarylsulfonamides.
Scheme 99: Atroposelective bromo-functionalization of alkynylarenes.
Scheme 100: Sulfenylation-induced atroposelective cyclization.
Scheme 101: Atroposelective O-sulfonylation of isochromenone-indoles.
Scheme 102: NHC-catalyzed atroposelective N-acylation of anilines.
Scheme 103: Peptide-catalyzed atroposelective ring-opening of lactones.
Scheme 104: Peptide-catalyzed coupling of 2-naphthols with quinones.
Scheme 105: Atroposelective nucleophilic aromatic substitution of fluoroarenes.
Steroid diversification by multicomponent reactions
- Leslie Reguera,
- Cecilia I. Attorresi,
- Javier A. Ramírez and
- Daniel G. Rivera
Beilstein J. Org. Chem. 2019, 15, 1236–1256, doi:10.3762/bjoc.15.121
- groups like CH3 and OMe does only partially. Both steric and electronic effects can be explained from the reactivity of the diimine intermediate. An electron-withdrawing group promotes the nucleophilic attack of the ketoimine N by increasing the partially positive charge of the imine C. In general
Graphical Abstract
Figure 1: Structures of natural steroids of A) animal and B) plant origin.
Scheme 1: Synthesis of a steroidal β-lactam by Ugi reaction of a cholanic aldehyde [14].
Scheme 2: Synthetic route to steroidal 2,5-diketopiperazines based on a diastereoselective Ugi-4CR with an an...
Scheme 3: Multicomponent synthesis of a heterocycle–steroid hybrid using a ketosteroid as carbonyl component [18]....
Scheme 4: Synthesis of peptidomimetic–steroid hybrids using the Ugi-4CR with spirostanic amines and carboxyli...
Scheme 5: Synthesis of azasteroids using the Ugi-4CR with androstanic and pregnanic carboxylic acids [22].
Figure 2: Ugi-4CR-derived library of androstanic azasteroids with diverse substitution patterns at the phenyl...
Scheme 6: Synthesis of 4-azacholestanes by an intramolecular Ugi-4C-3R [26].
Scheme 7: Synthesis of amino acid–steroid hybrid by multiple Ugi-4CR using steroidal isocyanides [29].
Scheme 8: Synthesis of ecdysteroid derivatives by Ugi-4CR using a steroidal isocyanide [30].
Scheme 9: Stereoselective multicomponent synthesis of a steroid–tetrahydropyridine hybrid using a chiral bifu...
Scheme 10: Pd(II)-catalyzed three-component reaction with an alkynyl seco-cholestane [34].
Scheme 11: Multicomponent synthesis of steroid–thiazole hybrids from a steroidal ketone [36].
Scheme 12: Synthesis of cholanic pseudo-peptide derivatives by novel MCRs based on the reactivity of ynamide [37,38].
Scheme 13: Synthesis of steroid-fused pyrimidines and pyrimidones using the Biginelli-3CR [39,42,43].
Scheme 14: Synthesis of steroidal pyridopyrimidines by a reaction sequence comprising a 4CR followed by a post...
Scheme 15: Synthesis of steroid-fused pyrimidines by MCR of 2-hydroxymethylene-3-ketosteroids [46].
Scheme 16: Synthesis of steroid-fused naphthoquinolines by the Kozlov–Wang MCR using ketosteroids [50,51].
Scheme 17: Conjugation of steroids to carbohydrates and peptides by the Ugi-4CR [62,63].
Scheme 18: Solid-phase multicomponent conjugation of peptides to steroids by the Ugi-4CR [64].
Scheme 19: Solid-phase multicomponent conjugation of peptides to steroids by the Petasis-3CR [68].
Scheme 20: Synthesis of steroidal macrobicycles (cages) by multiple multicomponent macrocyclizations based on ...
Scheme 21: One-pot synthesis of steroidal cages by double Ugi-4CR-based macrocyclizations [76].
Substrate dependent reaction channels of the Wolff–Kishner reduction reaction: A theoretical study
- Shinichi Yamabe,
- Guixiang Zeng,
- Wei Guan and
- Shigeyoshi Sakaki
Beilstein J. Org. Chem. 2014, 10, 259–270, doi:10.3762/bjoc.10.21
- hydrazine (Me2C=N–NH2) was obtained. The channel involves two likely proton-transfer routes. However, it was found that the base-free reaction was unlikely at the N2 extrusion step from the isopropyl diimine intermediate (Me2C(H)–N=N–H). Two base-catalyzed reactions were investigated by models of the ketone
- product. For both ketone substrates, the diimines undergoing E2 reactions were found to be key intermediates. Keywords: acetone; acetophenone; DFT calculations; diimine intermediate; reduction reaction; transition states; Wolff–Kishner; Introduction The Wolff–Kishner (W-K) reduction is an organic
- . From hydrazone, the hydrazone anion is formed, which was first suggested by Seibert [6][7]. From the anion, there are two routes (a) and (b). In (a), the proton is [1,3]-shifted to give an isomer anion, R1(R2)HC–N=N(−). In (b), a diimine intermediate R1(R2)HC–N=N–H is generated [6][7][8]. Both routes
Graphical Abstract
Scheme 1: The Wolff–Kishner (W-K) reduction. DEG, diethylene glycol (HO–C2H4–O–C2H4–OH), is usually used as a...
Scheme 2: Mechanism of the Wolff–Kishner reduction. The route (a) is taken from ref. [6] and (b) from refs. [5,7,8].
Scheme 3: An uncatalyzed (without base) Knoevenagel condensation in water. Experimental conditions and yields...
Scheme 4: Reaction models of neutral (a) and anionic (b) systems. Water molecules are linked to oxygen lone-p...
Figure 1: Geometric changes of the neutral Wolff–Kishner reduction reaction. The employed model is shown in Scheme 4a ...
Scheme 5: A CT complex between R1R2C=O and H2N–NH2 assisted by two hydrogen networks. R3–OH is an alcohol mol...
Figure 2: Energy changes of the neutral W-K reaction of acetone. Geometric changes are shown in Figure 1 and Figure S...
Figure 3: Geometric changes of the base-promoted Wolff–Kishner reduction reaction. The model employed is show...
Figure 4: Energy changes of the OH− containing W-K reaction of acetone calculated by B3LYP/6-311+G**. Geometr...
Scheme 6: The main part of TS6. The N1···H26 hydrogen bond is converted into the C1–H26 covalent bond.
Figure 5: A trans-diimine → propane conversion step corresponding to TS6 in Figure 3. The system is composed of trans...
Figure 6: Geometric changes of the base-promoted Wolff–Kishner reduction reaction of acetophenone [Me–C(=O)–P...
Figure 7: Energy changes of the OHˉ containing W-K reaction of acetophenone. Geometric changes are shown in Figure 6....
Scheme 7: Elementary processes of the W-K reduction obtained by DFT calculations. From the diimine intermedia...
