Synthetic studies toward paraherquamides E and F and related 13C-labeled putative biosynthetic intermediates: stereocontrolled synthesis of the α-alkyl-β-methylproline ring system
作者:Konrad Sommer、Robert M. Williams
DOI:10.1016/j.tet.2008.05.068
日期:2008.7
putative biosynthesis intermediates have been prepared efficiently in six steps and 24% overall yield. The key steps are a 5-exo-trig cyclization of a zinc enolate on an unactivated alkene and a stereocontrolled alkylation of the enolate formed from 3S-methyl-pyrrolidine-1,2R-dicarboxylic acid 1-tert-butyl ester 2-ethyl ester.