New general synthesis of a-alkoxyketones via a¢-alkylation, a-alkylation and a,a¢-dialkylation of a-alkoxyketimines†

a-Methoxyand a-ethoxyketones, as important intermediates in organic synthesis and flavor compounds in food chemistry, were synthesized by deprotonation of N-(1-alkoxy-2-propylidene)isopropylamine, prepared by condensation of the corresponding a-alkoxyacetone with isopropylamine, and subsequent reaction of the corresponding 1-azaallylic anions with alkyl halides to afford a¢-alkylated, a-alkylated and a,a¢-dialkylated ketimines. Hydrolysis of the imino function led to the desired substituted a-alkoxyketones. The ratio of a-, a¢-, and a,a¢-(di)alkylated compounds depended on the amount of base used and on the nature of the alkylating reagent.