High Kinetic Resolution in the Addition of a Racemic Allenylzinc onto Enantiopure <i>N</i>-<i>tert</i>-Butanesulfinimines: Concise Synthesis of Enantiopure <i>trans</i>-2-Ethynylaziridines<sup>1</sup>
作者:Fabrice Chemla、Franck Ferreira
DOI:10.1021/jo0490696
日期:2004.11.1
Enantiopure trans-ethynyl N-tert-butanesulfinylaziridines (R-s)-6 were prepared in good to excellent yields by the condensation of the racemic allenylzinc species 1 derived from 3-chloro-l-trimethyl-silylpropyne onto the corresponding enantiopure N-tert-butanesulfinimines (R-s)-5. The absolute stereochemistry of enantiopure N-tert-butanesulfinylaziridines (R-s)-6 was shown to be (R-s,2R,3R) and results from a chelate-type transition state in which the zinc atom of allenylzinc 1 is coordinated by both the nitogen and the oxygen atoms of the imine. Further removal of the N-tert-butanesulfinyl auxiliary of alkyl 3-substituted and 3,3-disubstituted ethynyl N-tert-butanesulfinylaziridines (Rs)-6 could be achieved by treatment with HCl in MeOH affording the corresponding deprotected aziridines (2R,3R)-9 and (2R)-9 respectively as enantiomerically pure compounds.
Ring-Opening of<i>N-tert</i>-Butanesulfinylethynylaziridines with Lithium Tris(dimethylphenylsilyl)zincate: Stereoselective Access to 4-Amino-1-allenylsilanes
作者:Valentin N. Bochatay、Youssouf Sanogo、Fabrice Chemla、Franck Ferreira、Olivier Jackowski、Alejandro Pérez-Luna
DOI:10.1002/adsc.201500347
日期:2015.9.14
N‐tert‐butanesulfinylethynylaziridines with lithiumtris(dimethylphenylsilyl)zincate is reported. The reaction is demonstrated to be both stereoselective and stereospecific and to proceed through an anti‐SN2′ process. Further deprotection of the nitrogen atom under mild conditions allows access to 4‐amino‐1‐(dimethylphenylsilyl)allenes with high yields and levels of stereoselectivity.
据报道,N-叔丁烷亚磺酰基乙炔基氮丙啶与三(二甲基苯基甲硅烷基)锌酸锂开环。该反应被证明既具有立体选择性也具有立体特异性,并且会通过抗-S N 2'过程进行。在温和条件下对氮原子进行进一步的脱保护,可以以高收率和立体选择性的水平获得4-氨基-1-(二甲基苯基甲硅烷基)丙烯。