Process for chiral 3-(1-amino-1,1-bisalkylmethyl)-1-substituted-pyrrolidines

摘要

The process for the preparation of chiral 3-(1-amino-1,1-bisalkylmethyl)-1-substituted-pyrrolidines used as key intermediates for the preparation of naphthyridine and quinolone antibacterial agents which comprises reacting readily available chiral 1-substituted-3-pyrrolidinols to their corresponding chiral sulfonate esters; converting the sulfonate esters to chiral 1-substituted-3-cyanopyrrolidines having an inverse configuration, and then dialkylating the chiral cyanopyrrolidines with alkyl lithium in the presence of a Lewis acid without racemization at the asymmetric carbon atom is described.