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Search for "regioselective alkylation" in Full Text gives 8 result(s) in Beilstein Journal of Organic Chemistry.
Regioselective alkylation of a versatile indazole: Electrophile scope and mechanistic insights from density functional theory calculations
- Pengcheng Lu,
- Luis Juarez,
- Paul A. Wiget,
- Weihe Zhang,
- Krishnan Raman and
- Pravin L. Kotian
Beilstein J. Org. Chem. 2024, 20, 1940–1954, doi:10.3762/bjoc.20.170
Graphical Abstract
Figure 1: Indazole-containing bioactive molecules.
Figure 2: Tautomerism of indazole.
Scheme 1: NMR, NOE, and yield data of compounds 8 and 9.
Scheme 2: Synthesis of compounds P1 and P2.
Figure 3: DFT-calculated deprotonation of 6 with Cs2CO3 in implicit THF with the temperature of the calculati...
Figure 4: DFT-calculated Cs+-coordinated complexes with different enolate forms of 6(N-H) calculated as isola...
Figure 5: DFT-calculated reaction coordinate diagram for the reaction of 6 under conditions A. Concerning con...
Figure 6: DFT-calculated energy for the deprotonation of 6 by the DMAD anion.
Figure 7: DFT-calculations concerning a coordinated Mitsunobu reaction pathway.
Figure 8: Reaction coordinate diagram of 6(N-H) reacting under conditions B. All calculated energies in kcal/...
Figure 9: Reaction of 18 under conditions A and B (top), and proposed chelation/coordination pathways to acco...
Figure 10: DFT-calculated reaction coordinate diagram for the reaction of 18 under conditions A.
Figure 11: DFT-calculated reaction coordinate diagram for the reaction of 18 under conditions B. Ball-and-stic...
Scheme 3: Reaction of 21 under conditions A and B; amultiple purifications; bdetermined by LC–MS.
Figure 12: DFT-calculated transition-state structures and energies of 21 under conditions A (top) and conditio...
Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer
- Mohd Farhan Ansari,
- Atul Kumar Maurya,
- Abhishek Kumar and
- Saravanakumar Elangovan
Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98
- and methanol as a C1 source [86]. A total of 28 desired aminomethylated aromatic products were isolated with moderate to good yields (Scheme 56). Later, Rueping and co-workers developed the regioselective alkylation of indolines with alcohols as the alkylating agent using a manganese-pincer catalyst
Graphical Abstract
Scheme 1: General scheme of the borrowing hydrogen (BH) or hydrogen auto-transfer (HA) methodology.
Scheme 2: General scheme for C–N bond formation. A) Traditional cross-couplings with alkyl or aryl halides. B...
Figure 1: Manganese pre-catalysts used for the N-alkylation of amines with alcohols.
Scheme 3: Manganese(I)-pincer complex Mn1 used for the N-alkylation of amines with alcohols and methanol.
Scheme 4: N-Methylation of amines with methanol using Mn2.
Scheme 5: C–N-Bond formation with amines and methanol using PN3P-Mn complex Mn3 reported by Sortais et al. [36]. a...
Scheme 6: Base-assisted synthesis of amines and imines with Mn4. Reaction assisted by A) t-BuOK and B) t-BuON...
Scheme 7: Coupling of alcohols and hydrazine via the HB approach reported by Milstein et al. [38]. aReaction time...
Scheme 8: Proposed mechanism for the coupling of alcohols and hydrazine catalyzed by Mn5.
Scheme 9: Phosphine-free manganese catalyst for N-alkylation of amines with alcohols reported by Balaraman an...
Scheme 10: N-Alkylation of sulfonamides with alcohols.
Scheme 11: Mn–NHC catalyst Mn6 applied for the N-alkylation of amines with alcohols. a3 mol % of Mn6 were used....
Scheme 12: N-Alkylation of amines with primary and secondary alcohols. a80 °C, b100 °C.
Scheme 13: Manganese(III)-porphyrin catalyst for synthesis of tertiary amines.
Scheme 14: Proposed mechanism for the alcohol dehydrogenation with Mn(III)-porphyrin complex Mn7.
Scheme 15: N-Methylation of nitroarenes with methanol using catalyst Mn3.
Scheme 16: Mechanism of manganese-catalyzed methylation of nitroarenes using Mn3 as the catalyst.
Scheme 17: Bidentate manganese complex Mn8 applied for the N-alkylation of primary anilines with alcohols. aOn...
Scheme 18: N-Alkylation of amines with alcohols in the presence of manganese salts and triphenylphosphine as t...
Scheme 19: N-Alkylation of diazo compounds with alcohols using catalyst Mn9.
Scheme 20: Proposed mechanism for the amination of alcohols with diazo compounds catalyzed by catalyst Mn9.
Scheme 21: Mn1 complex-catalyzed synthesis of polyethyleneimine from ethylene glycol and ethylenediamine.
Scheme 22: Bis-triazolylidene-manganese complex Mn10 for the N-alkylation of amines with alcohols.
Figure 2: Manganese complexes applied for C-alkylation reactions of ketones with alcohols.
Scheme 23: General scheme for the C–C bond formation with alcohols and ketones.
Scheme 24: Mn1 complex-catalyzed α-alkylation of ketones with primary alcohols.
Scheme 25: Mechanism for the Mn1-catalyzed alkylation of ketones with alcohols.
Scheme 26: Phosphine-free in situ-generated manganese catalyst for the α-alkylation of ketones with primary al...
Scheme 27: Plausible mechanism for the Mn-catalyzed α-alkylation of ketones with alcohols.
Scheme 28: α-Alkylation of esters, ketones, and amides using alcohols catalyzed by Mn11.
Scheme 29: Mono- and dialkylation of methylene ketones with primary alcohols using the Mn(acac)2/1,10-phenanth...
Scheme 30: Methylation of ketones with methanol and deuterated methanol.
Scheme 31: Methylation of ketones and esters with methanol. a50 mol % of t-BuOK were used, bCD3OD was used ins...
Scheme 32: Alkylation of ketones and secondary alcohols with primary alcohols using Mn4.
Scheme 33: Bidentate manganese-NHC complex Mn6 applied for the synthesis of alkylated ketones using alcohols.
Scheme 34: Mn1-catalyzed synthesis of substituted cycloalkanes by coupling diols and secondary alcohols or ket...
Scheme 35: Proposed mechanism for the synthesis of cycloalkanes via BH method.
Scheme 36: Synthesis of various cycloalkanes from methyl ketones and diols catalyze by Mn13. aReaction time wa...
Scheme 37: N,N-Amine–manganese complex (Mn13)-catalyzed alkylation of ketones with alcohols.
Scheme 38: Naphthyridine‑N‑oxide manganese complex Mn14 applied for the alkylation of ketones with alcohols. a...
Scheme 39: Proposed mechanism of the naphthyridine‑N‑oxide manganese complex (Mn14)-catalyzed alkylation of ke...
Scheme 40: α-Methylation of ketones and indoles with methanol using Mn15.
Scheme 41: α-Alkylation of ketones with primary alcohols using Mn16. aNMR yield.
Figure 3: Manganese complexes used for coupling of secondary and primary alcohols.
Scheme 42: Alkylation of secondary alcohols with primary alcohols catalyzed by phosphine-free catalyst Mn17. a...
Scheme 43: PNN-Manganese complex Mn18 for the alkylation of secondary alcohols with primary alcohols.
Scheme 44: Mechanism for the Mn-pincer catalyzed C-alkylation of secondary alcohols with primary alcohols.
Scheme 45: Upgrading of ethanol with methanol for isobutanol production.
Scheme 46: Mn-Pincer catalyst Mn19 applied for the β-methylation of alcohols with methanol. a2.0 mol % of Mn19...
Scheme 47: Functionalized ketones from primary and secondary alcohols catalyzed by Mn20. aMn20 (5 mol %), NaOH...
Scheme 48: Synthesis of γ-disubstituted alcohols and β-disubstituted ketones through Mn9-catalyzed coupling of...
Scheme 49: Proposed mechanism for the Mn9-catalyzed synthesis of γ-disubstituted alcohols and β-disubstituted ...
Scheme 50: Dehydrogenative coupling of ethylene glycol and primary alcohols catalyzed by Mn4.
Scheme 51: Mn18-cataylzed C-alkylation of unactivated esters and amides with alcohols.
Scheme 52: Alkylation of amides and esters using Mn21.
Scheme 53: α-Alkylation of nitriles with primary alcohols using in situ-generated manganese catalyst.
Scheme 54: Proposed mechanism for the α-alkylation of nitriles with primary alcohols.
Scheme 55: Mn9-catalyzed α-alkylation of nitriles with primary alcohols. a1,4-Dioxane was used as solvent, 24 ...
Figure 4: Manganese complexes used for alkylation of heterocyclic compounds.
Scheme 56: Aminomethylation of aromatic compounds with secondary amines and methanol catalyzed by Mn22.
Scheme 57: Regioselective alkylation of indolines with alcohols catalyzed by Mn9. aMn9 (4 mol %), 48 h.
Scheme 58: Proposed mechanism for the C- and N-alkylation of indolines with alcohols.
Scheme 59: C-Alkylation of methyl N-heteroarenes with primary alcohols catalyzed by Mn1. aTime was 60 h.
Scheme 60: C-Alkylation of oxindoles with secondary alcohols.
Scheme 61: Plausible mechanism for the Mn23-catalyzed C-alkylation of oxindoles with secondary alcohols.
Scheme 62: Synthesis of C-3-alkylated products by coupling alcohols with indoles and aminoalcohols.
Scheme 63: C3-Alkylation of indoles using Mn1.
Scheme 64: C-Methylation of indoles with Mn15 and methanol.
Scheme 65: α-Alkylation of 2-oxindoles with primary and secondary alcohols catalyzed by Mn25. aReaction carrie...
Scheme 66: Dehydrogenative alkylation of indolines with Mn1. aMn1 (5.0 mol %) was used.
Scheme 67: Synthesis of bis(indolyl)methane derivatives from indoles and alcohols catalyzed by Mn26. aMn26 (5....
Scheme 68: One-pot synthesis of pyrimidines via BH.
Scheme 69: Synthesis of pyrroles from alcohols and aminoalcohols using Mn4.
Scheme 70: Synthesis of pyrroles via multicomponent reaction catalyzed by Mn12.
Scheme 71: Friedländer quinoline synthesis using an in situ-generated phosphine-free manganese catalyst.
Scheme 72: Quinoline synthesis using bis-N-heterocyclic carbene-manganese catalyst Mn6.
Scheme 73: Quinoline synthesis using manganese(III)-porphyrin catalyst Mn7.
Scheme 74: Manganese-catalyzed tetrahydroquinoline synthesis via borrowing BH.
Scheme 75: Proposed mechanism for the manganese-catalyzed tetrahydroquinoline synthesis.
Scheme 76: Synthesis of C3-alkylated indoles using Mn24.
Scheme 77: Synthesis of C-3-alkylated indoles using Mn1.
Scheme 78: C–C Bond formation by coupling of alcohols and ylides.
Scheme 79: C-Alkylation of fluorene with alcohols catalyzed by Mn24.
Scheme 80: Proposed mechanism for the C-alkylation of fluorene with alcohols catalyzed by Mn24.
Scheme 81: α-Alkylation of sulfones using Mn-PNN catalyst Mn28.
Pyridine C(sp2)–H bond functionalization under transition-metal and rare earth metal catalysis
- Haritha Sindhe,
- Malladi Mounika Reddy,
- Karthikeyan Rajkumar,
- Akshay Kamble,
- Amardeep Singh,
- Anand Kumar and
- Satyasheel Sharma
Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62
- challenge. In this context, a regioselective alkylation of ortho-unsubstituted or substituted unactivated pyridines with acrylates and acrylamides under Rh(I) catalysis has been demonstrated by Ellman and co-workers [59]. The authors observed that in the presence of [Rh(cod)Cl]2 as catalyst, dppe as ligand
Graphical Abstract
Figure 1: Representative examples of bioactive natural products and FDA-approved drugs containing a pyridine ...
Scheme 1: Classical and traditional methods for the synthesis of functionalized pyridines.
Scheme 2: Rare earth metal (Ln)-catalyzed pyridine C–H alkylation.
Scheme 3: Pd-catalyzed C–H alkylation of pyridine N-oxide.
Scheme 4: CuI-catalyzed C–H alkylation of N-iminopyridinium ylides with tosylhydrazones (A) and a plausible r...
Scheme 5: Zirconium complex-catalyzed pyridine C–H alkylation.
Scheme 6: Rare earth metal-catalyzed pyridine C–H alkylation with nonpolar unsaturated substrates.
Scheme 7: Heterobimetallic Rh–Al complex-catalyzed ortho-C–H monoalkylation of pyridines.
Scheme 8: Mono(phosphinoamido)-rare earth complex-catalyzed pyridine C–H alkylation.
Scheme 9: Rhodium-catalyzed pyridine C–H alkylation with acrylates and acrylamides.
Scheme 10: Ni–Al bimetallic system-catalyzed pyridine C–H alkylation.
Scheme 11: Iridium-catalyzed pyridine C–H alkylation.
Scheme 12: para-C(sp2)–H Alkylation of pyridines with alkenes.
Scheme 13: Enantioselective pyridine C–H alkylation.
Scheme 14: Pd-catalyzed C2-olefination of pyridines.
Scheme 15: Ru-catalyzed C-6 (C-2)-propenylation of 2-arylated pyridines.
Scheme 16: C–H addition of allenes to pyridines catalyzed by half-sandwich Sc metal complex.
Scheme 17: Pd-catalyzed stereodivergent synthesis of alkenylated pyridines.
Scheme 18: Pd-catalyzed ligand-promoted selective C3-olefination of pyridines.
Scheme 19: Mono-N-protected amino acids in Pd-catalyzed C3-alkenylation of pyridines.
Scheme 20: Amide-directed and rhodium-catalyzed C3-alkenylation of pyridines.
Scheme 21: Bimetallic Ni–Al-catalyzed para-selective alkenylation of pyridine.
Scheme 22: Arylboronic ester-assisted pyridine direct C–H arylation.
Scheme 23: Pd-catalyzed C–H arylation/benzylation with toluene.
Scheme 24: Pd-catalyzed pyridine C–H arylation with potassium aryl- and heteroaryltrifluoroborates.
Scheme 25: Transient activator strategy in pyridine C–H biarylation.
Scheme 26: Ligand-promoted C3-arylation of pyridine.
Scheme 27: Pd-catalyzed arylation of nicotinic and isonicotinic acids.
Scheme 28: Iron-catalyzed and imine-directed C–H arylation of pyridines.
Scheme 29: Pd–(bipy-6-OH) cooperative system-mediated direct pyridine C3-arylation.
Scheme 30: Pd-catalyzed pyridine N-oxide C–H arylation with heteroarylcarboxylic acids.
Scheme 31: Pd-catalyzed C–H cross-coupling of pyridine N-oxides with five-membered heterocycles.
Scheme 32: Cu-catalyzed dehydrative biaryl coupling of azine(pyridine) N-oxides and oxazoles.
Scheme 33: Rh(III)-catalyzed cross dehydrogenative C3-heteroarylation of pyridines.
Scheme 34: Pd-catalyzed C3-selective arylation of pyridines.
Scheme 35: Rhodium-catalyzed oxidative C–H annulation of pyridines to quinolines.
Scheme 36: Rhodium-catalyzed and NHC-directed C–H annulation of pyridine.
Scheme 37: Ni/NHC-catalyzed regio- and enantioselective C–H cyclization of pyridines.
Scheme 38: Rare earth metal-catalyzed intramolecular C–H cyclization of pyridine to azaindolines.
Scheme 39: Rh-catalyzed alkenylation of bipyridine with terminal silylacetylenes.
Scheme 40: Rollover cyclometallation in Rh-catalyzed pyridine C–H functionalization.
Scheme 41: Rollover pathway in Rh-catalyzed C–H functionalization of N,N,N-tridentate chelating compounds.
Scheme 42: Pd-catalyzed rollover pathway in bipyridine-6-carboxamides C–H arylation.
Scheme 43: Rh-catalyzed C3-acylmethylation of bipyridine-6-carboxamides with sulfoxonium ylides.
Scheme 44: Rh-catalyzed C–H functionalization of bipyridines with alkynes.
Scheme 45: Rh-catalyzed C–H acylmethylation and annulation of bipyridine with sulfoxonium ylides.
Scheme 46: Iridium-catalyzed C4-borylation of pyridines.
Scheme 47: C3-Borylation of pyridines.
Scheme 48: Pd-catalyzed regioselective synthesis of silylated dihydropyridines.
Regioselective N-alkylation of the 1H-indazole scaffold; ring substituent and N-alkylating reagent effects on regioisomeric distribution
- Ryan M. Alam and
- John J. Keating
Beilstein J. Org. Chem. 2021, 17, 1939–1951, doi:10.3762/bjoc.17.127
- electrophile under conditions A (Table 6, entry 8) furnished the desired N-1 regioisomer 75 in very good isolated yield (81%). These latter results would suggest that secondary alkyl tosylates are more suitable than their corresponding halide counterparts, for N-1 regioselective alkylation, under these
Graphical Abstract
Figure 1: Examples of indazole natural products (1 and 2) and synthetic biologically active indazole derivati...
Scheme 1: Synthetic approaches to N-1 substituted indazole derivatives [12-14].
Scheme 2: N-Alkylation of indazole 9 under Mitsunobu conditions shows a strong preference (ratio N-1 (10):N-2...
Figure 2: Observation of a 1H–13C correlation between the C-7a (blue circle) or C-3 (red circle) atom of the ...
Figure 3: C-3 substituted indazole derivatives (12–24) employed to investigate C-3 substituent effects on ind...
Scheme 3: Proposed mechanism for the regioselective N-1 alkylation of indazoles 9, 19, and 21–24 in the prese...
An improved synthesis of adefovir and related analogues
- David J. Jones,
- Eileen M. O’Leary and
- Timothy P. O’Sullivan
Beilstein J. Org. Chem. 2019, 15, 801–810, doi:10.3762/bjoc.15.77
- phosphonate (11) was condensed with paraformaldehyde in the presence of catalytic triethylamine (Scheme 2) [41]. Iodide 9 was accessed in two steps from adenine (3). The highly regioselective alkylation of adenine (3) with an excess (4.0 equiv) of 1,2-dibromoethane furnished bromide 12 in 78% yield. Despite
Graphical Abstract
Figure 1: Adefovir (1) and its prodrug 2.
Scheme 1: Literature syntheses of 1.
Figure 2: Retrosynthetic analysis of 6 to synthons 9 and 10.
Scheme 2: Forward synthesis of 6 from 9 and 10.
Figure 3: Retrosynthesis of 6 to synthons 14 and 3.
Scheme 3: Application of related alkyl iodide 15 [52].
Scheme 4: Synthesis of 6 and 20 via iodide 14.
Scheme 5: Synthesis of phosphonate 6 using novel salt 21.
Scheme 6: Application of iodide 14 in the synthesis of adefovir analogues.
Figure 4: HMBC spectrum confirms N7-selectivity for the major product 29.
Scheme 7: Attempted synthesis of adefovir dipivoxil (2) exploiting phosphonate 33.
Studies towards the synthesis of hyperireflexolide A
- G. Hari Mangeswara Rao
Beilstein J. Org. Chem. 2018, 14, 2106–2111, doi:10.3762/bjoc.14.185
- the methyl group at C-10 was achieved by treatment of 8 with 1.1 equiv of K2CO3 in the presence of MeI to give bis-methylated γ-lactone-fused β-ketoester 9 in 72% yield (Scheme 3). These results demonstrated that regioselective alkylation at the two sites were possible. Notably, one diastereomeric
Graphical Abstract
Figure 1: Hyperireflexolide A.
Scheme 1: Retrosynthetic strategy.
Scheme 2: Hydrolysis of dimethyl ketal 5.
Scheme 3: Alkylation of γ-lactone-fused β-ketoester 6.
Scheme 4: Synthesis of α,β-unsaturated ketone 11.
Synthesis and supramolecular properties of regioisomers of mononaphthylallyl derivatives of γ-cyclodextrin
- Markéta Bláhová,
- Sergey K. Filippov,
- Lubomír Kováčik,
- Jiří Horský,
- Simona Hybelbauerová,
- Zdenka Syrová,
- Tomáš Křížek and
- Jindřich Jindřich
Beilstein J. Org. Chem. 2017, 13, 2509–2520, doi:10.3762/bjoc.13.248
- . Keywords: γ-cyclodextrin; naphthylallyl derivatives; regioselective alkylation; supramolecular properties; synthesis; Introduction Cyclodextrins [1] (CDs) are cyclic oligosaccharides with a cone-shaped cavity formed by α-1,4-linked D-glucopyranose units. The most widely used CDs are α-, β-, and γ-CD with
Graphical Abstract
Scheme 1: Preparation of 2I-O-, 3I-O- and 6I-O-naphthylallyl derivatives of γ-CD by cross-metathesis.
Scheme 2: Preparation of 2-O-, 3-O- and 6-O-NA derivatives of γ-CD by direct alkylation (see Table 1 for the yields ...
Figure 1: Volume-weighted distribution functions for water solutions of 2-O- (2a), 3-O- (2b), and 6-O- (2c) N...
Figure 2: Distribution functions for 2-O- (2a), 3-O- (2b), and 6-O- (2c) NA-γ-CD regioisomers in 50% MeOH (v/...
Figure 3: Volume-weighted distribution functions for the 3-O- (2b) and 6-O- (2c) NA-γ-CD regioisomer at diffe...
Figure 4: Effect of increasing concentration and sonication on the morphology of the 3-O-derivative 2b. A to ...
Figure 5: Effect of increasing concentration and sonication on the morphology of the 2-O-derivative 2a. A: 2 ...
Figure 6: Effect of increasing concentration and sonication on the morphology of the 6-O-derivative 2c. A: 0....
Figure 7: Heat change for injection per mole of NA-γ-CD added as a function of the total concentration of NA-...
Figure 8: 1H NMR spectra of 2-O-derivative 2a in D2O at concentrations of 100, 10, and 1 mM.
Figure 9: 1H NMR spectra of 3-O-derivative 2b in D2O at concentrations of 100, 10, and 1 mM.
Figure 10: Putative objects and interactions in naphthylallyl-γ-CD solution, depicted schematically for 6I-O-n...
AgOTf-catalyzed one-pot reactions of 2-alkynylbenzaldoximes with α,β-unsaturated carbonyl compounds
- Qiuping Ding,
- Dan Wang,
- Puying Luo,
- Meiling Liu,
- Shouzhi Pu and
- Liyun Zhou
Beilstein J. Org. Chem. 2013, 9, 1949–1956, doi:10.3762/bjoc.9.231
- regioselective alkylation of isoquinoline N-oxide and its derivatives with sulfoxides for the synthesis of 1-alkylated isoquinolines [40]. We also reported the synthesis of 1-arylated 1,3-disubstituted isoquinoline N-oxides in a one-pot reaction characterized by a Ag-catalyzed intramolecular addition cyclization
Graphical Abstract
Scheme 1: Proposed route for the AgOTf-catalyzed one-pot reaction of 2-alkynylbenzaldoxime with an α,β-unsatu...
Scheme 2: Synthesis of 1-alkylated isoquinoline 3a by a AgOTf-catalyzed one-pot reaction in different solvent...
Scheme 3: Pd-catalyzed one-pot alkenylation reaction of 2-alkynylbenzaldoxime 1a and butyl acrylate (2e).
