1,3-Dipolar Cycloadditions of Carbonyl Ylides to Aldimines: Scope, Limitations and Asymmetric Cycloadditions
作者:Staffan Torssell、Peter Somfai
DOI:10.1002/adsc.200600324
日期:2006.11
The development of a diastereoselective 1,3-dipolarcycloaddition of carbonylylides and imines for the synthesis of α-hydroxy-β-amino esters is described. The methodology is successfully applied to chiral α-methylbenzylimines affording enantiomerically pure syn-β-amino alcohols, which is exemplified with a short asymmetric synthesis of the paclitaxel side-chain. The use of chiral Rh(II) carboxylate
Stereoselective synthesis of CF3-substituted aziridines by Lewis acid-mediated aziridination of aldimines with diazoacetates
作者:Takahiko Akiyama、Satoshi Ogi、Kohei Fuchibe
DOI:10.1016/s0040-4039(03)00854-2
日期:2003.5
Treatment of trifluoroacetaldehyde N,O-acetal with diazoacetate in the presence of a Lewis acid furnished CF3-substituted aziridinecarboxylates in good yields. Both cis and trans isomers were obtained stereoselectively by the proper choice of the ester substituents. Use of a chiral diazoacetate derived from (R)-pantolactone led to highly diastereoselective aziridination (94% de). (C) 2003 Elsevier Science Ltd. All rights reserved.