An easy access to enantio-enriched α-substituted aldehydes by carbolithiation of β-phenyl or β-silyl-α,β-ethylenic aldehydes, protected with the monolithioamide of a chiral diamine
摘要:
Lithium amide derived from N,N,N'-trimethyl-l,2-diphenylethanediamine converts cinnamaldehyde to a lithium alkoxyamide which undergoes a regio- and stereoselective carbolithiation upon addition of various organolithiums. Subsequent hydrolysis or trapping with MeI delivers alpha -mono-, or alpha,beta -disubstituted 3-phenylpropanals with e.e.s of 76-96%. Extension to a silylated alpha -enal is possible. (C) 2001 Published by Elsevier Science Ltd.