α-Alkylation of α,β-Unsaturated Aldehyde Dimethylhydrazones Accompanied with the Double Bond Migration to β,γ

Article abstract of DOI:10.1246/bcsj.66.1759

Lithiated α,β-unsaturated aldehyde N,N-dimethylhydrazones reacted with alkyl halides accompanied by double bond migration to give α-alkylated β,γ-unsaturated aldehyde N,N-dimethylhydrazones in satisfactory yields.This reaction was found to be caused at the first step by deprotonation from a γ-carbon atom by lithium diisopropylamide.In the case of hydrazones with two kinds of γ-protons, deprotonation from the less hindered γ-carbon occurred selectively.Using this reaction, a novel sesquiterpene, 2,5,9-trimethyl-2-vinyl-4,8-decadienal, which has a vinyl group at the α-position, was synthesized in a good yield.