Reaction between hydrazines and chiral α-acetylenic ketones: synthesis of novel enantiomerically pure pyrazolyl-β-amino alcohols
作者:Gemma Cabarrocas、Montserrat Ventura、Miguel Maestro、José Mahı́a、José M Villalgordo
DOI:10.1016/s0957-4166(00)00204-4
日期:2000.6
A simple and efficient methodology toward the stereoselective synthesis of novel, enantiomerically pure, pyrazolyl-β-amino alcohols is presented. Thus, when hydrazines 4a,b were allowed to react at 0°C with chiral α-acetylenic ketones of type 3, pyrazolyl oxazolidine derivatives 5a–d were formed with total regioselectivity in 92–97% yield. Subsequent oxazolidine ring opening by means of TFA, and re-protection