Lipase-Catalyzed Resolution of (2R*,3S*)- and (2R*,3R*)-3-Methyl-3-phenyl-2-aziridinemethanol at Low Temperatures and Determination of the Absolute Configurations of the Four Stereoisomers
摘要:
Lipase-catalyzed resolution of (2R*,3S*)-3-methyl-3-phenyl-2-aziridinemethanol, (+/-)-2, at low temperatures gave synthetically useful (2R,3S)-2 and its acetate (2S,3R)-2a with (2S)-selectivity (E = 55 at -40degreesC), while a similar reaction of (2R*,3R*)-3-methyl-3-phenyl-2-aziridinemethanol, (+/-)-3, gave (2S,3S)-3 and its acetate (2R,3R)-3a with (2R)-selectivity (E = 73 at -20degreesC). Compound (+/-)-2 was prepared conveniently via diastereoselective addition of MeMgBr to tert-butyl 3-phenyl2H-azirine-2-carboxylate, (+/-)-1a, which was successfully prepared by the Neber reaction of oxime tosylate of tert-butyl benzoyl acetate 7a. The tert-butyl ester was requisite to promote this reaction. For determination of the absolute configuration of (2S,3R)-2a, enantiopure (2S,3R)-2 was independently prepared in three steps involving diastereoselective methylation of 3-phenyl-2H-azirine-2-methanol, (S)-10, with MeMgBr. The absolute configuration of (2S,3S)-3 was determined by X-ray analysis of the corresponding N-(S)-2-(6-methoxy-2-naphthyl)propanoyl derivative (S,S,S)-13.
Rh<sup>II</sup>-Catalyzed [3+2] Cycloaddition of 2 <i>H</i>-Azirines with<i>N</i>-Sulfonyl-1,2,3-Triazoles
作者:Yun-Zhou Zhao、Hai-Bin Yang、Xiang-Ying Tang、Min Shi
DOI:10.1002/chem.201406460
日期:2015.2.23
RhII‐catalyzed intermolecular [3+2] cycloaddition of 2 H‐azirines with N‐sulfonyl‐1,2,3‐triazoles is disclosed, in which a series of fully functionalized pyrroles is produced via rhodium azavinyl carbene intermediates. A distinct feature of this reaction is that the azavinyl carbene serves as a [2C] equivalent, instead of as [1 C] or aza‐[3C] synthons, which have been reported previously in cyclopropanations
Lewis Acid-Catalyzed Diastereoselective Synthesis of Multisubstituted <i>N</i>-Acylaziridine-2-carboxamides from 2<i>H</i>-Azirines via Joullié–Ugi Three-Component Reaction
作者:Anikó Angyal、András Demjén、Edit Wéber、Anita K. Kovács、János Wölfling、László G. Puskás、Iván Kanizsai
DOI:10.1021/acs.joc.7b03189
日期:2018.4.6
A ZnCl2-catalyzed diastereoselective Joullié–Ugi three-component reaction from 2H-azirines, isocyanides, and carboxylic acids was established. The protocol allows the preparation of highly and diversely functionalized N-acylaziridine-2-carboxamide derivatives in up to 82% isolated yields. Moreover, the applicability of N-acylaziridines is demonstrated through a variety of transformations.
1,3-Dipolar Cycloaddition of Isatin-Derived Azomethine Ylides with 2<i>H</i>-Azirines: Stereoselective Synthesis of 1,3-Diazaspiro[bicyclo[3.1.0]hexane]oxindoles
作者:Anikó Angyal、András Demjén、Veronika Harmat、János Wölfling、László G. Puskás、Iván Kanizsai
DOI:10.1021/acs.joc.9b00242
日期:2019.4.5
A regio- and diastereoselective 1,3-dipolarcycloaddition of 2H-azirines with azomethine ylides generated in situ from isatins and α-amino acids has been elaborated, affording an unprecedented aziridine-fused spiro[imidazolidine-4,3′-oxindole] framework. This one-pot three-component reaction tolerates a wide range of substrates and enables the construction of highly diverse 1,3-diazaspiro[bicyclo[3
Regioselective Synthesis of Indolopyrazines through a Sequential Rhodium-Catalyzed Formal [3+3] Cycloaddition and Aromatization Reaction of Diazoindolinimines with Azirines
作者:Yonghyeon Baek、Chanyoung Maeng、Hyunseok Kim、Phil Ho Lee
DOI:10.1021/acs.joc.8b00115
日期:2018.2.16
A regioselective synthetic method for the preparation of indolopyrazines was demonstrated through a sequential Rh-catalyzed formal [3+3] cycloaddition and aromatization reaction of a wide range of diazoindolinimines with azirines. Because the previously reported synthetic methods afforded mixtures of indolopyrazines, the present method using unsymmetrical azirines has a strong advantage from a regioselectivity
Acid-Catalyzed 1,3-Dipolar Cycloaddition of 2<i>H</i>-Azirines with Nitrones: An Unexpected Access to 1,2,4,5-Tetrasubstituted Imidazoles
作者:Anikó Angyal、András Demjén、János Wölfling、László G. Puskás、Iván Kanizsai
DOI:10.1021/acs.joc.9b03288
日期:2020.3.6
The first 1,3-dipolarcycloaddition of 2H-azirines with nitrones, a straightforward approach toward the regioselective synthesis of 1,2,4,5-tetrasubstituted imidazoles, is reported. This trifluoroacetic acid-catalyzed protocol tolerates a broad range of aliphatic and aromatic substrates, offering an efficient access to highly diverse, multisubstituted imidazoles in isolated yields up to 83% under mild