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.
Unsymmetrical ketones were prepared by successive alkylation of acetone dimethylhydrazone. Application of this reaction to the synthesis of dihydrojasmone is described.
3-Methyl-2-cyclopenten-1-one N,N-dimethylhydrazone reacted with methyl vinyl ketone or acrylic acid derivatives to give a new bicyclic bifunctional compound in good yield in a polar aprotic solvent such as dimethylformamide.
The alkylation of 3-methyl-2-cyclopenten-1-one N, N-dimethylhydrazone was investigated and was found to mone and cis-jasmone were prepared in good yield. Isophorone dimethylhydrazone was also alkylated at the a-position, but for ionone dimethylhydrazone, the reaction occured at the a'-position (methyl carbon), not the a-position of the hydrazone.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.