Propargyl bromide as an excellent alpha-bromoacetone equivalent: Convenient and new route to alpha-aroylacetones

摘要

A variety of alpha-aroylacetones 4a-g have been prepared in excellent yields following a new protocol wherein alpha-aminonitriles la-g as the aryl acyl anion equivalents readily react with propargyl bromide as the alpha-bromoacetone equivalent. The alkylated product undergoes one-pot unmasking of the keto functionality along with Markovnikov's hydration of the terminal alkyne with CuSO(4)center dot 5H(2)O in aqueous methanol at 60 degrees C to furnish the desired target in excellent isolated yields.