Highly Stereoselective Metal-Free Catalytic Reduction of Imines: An Easy Entry to Enantiomerically Pure Amines and Natural and Unnatural α-Amino Esters
摘要:
A highly efficient catalytic stereoselective ketimine reduction is described. The combination of an inexpensive chiral organocatalyst, easily prepared in a single step, and of a very cheap removable chiral auxiliary allowed us to obtain enantiomerically pure amino compounds. The methodology allowed synthesis of chiral secondary and primary amines and natural and unnatural amino esters in high yields often with total control of the absolute stereochemistry.
efficient, metal-free highly stereoselective reduction of ketimines to chiralamines was developed. Different imines bearing a very cheap and removable chiral auxiliary were reduced simply by trichlorosilane in the presence of N,N-dimethyl-formamide, often in quantitative yield and complete control of the absolute stereochemistry, to afford highly enantiomerically enriched amines.
Imines derived from p-substituted acetophenones and (+) R-1-phenylethylamine are reduced by 3,5-diethoxycarbony1-2,6-dimethyl-1,4-dihydro-pyridine (Hantzsch ester), in acetonitrile, in the presence of magnesium perchlorate, to diastereomeric mixtures of the corresponding N-1-arylethyl, N-1-phenylethylamines. The reduction proceeds diastereoselectivity with the R,R-diastereomer being formed predominantly
[EN] IMPROVED PROCESS FOR THE SYNTHESIS OF 1-(4-METHOXYPHENYL) ETHYLAMINE AND ITS ISOMERS<br/>[FR] PROCÉDÉ AMÉLIORÉ POUR LA SYNTHÈSE DE 1-(4-MÉTHOXYPHÉNYL) ÉTHYLAMINE ET SES ISOMÈRES
申请人:SUVEN LIFE SCIENCES LTD
公开号:WO2015159170A2
公开(公告)日:2015-10-22
The present invention relates to an improved and efficient process for the preparation of highly useful and versatile chiral compound (S)-(-)-l-(4-methoxyphenyl) ethylamine of formula (1) and formula (1-R) from novel chiral compounds (S)-[l-(4-Methoxyphenyl)-ethylidene]-(l-phenylethyl)amine of formula (16) and (R)-[l-(4-Methoxyphenyl)-ethylidene]-(l-phenylethyl)amine of formula (16-R) respectively.