Substitution α to the Nitrogen in Dibenzylamine via Carbanion Intermediates

A method has been developed for introducing a variety of substituents into the position α to the nitrogen atom of dibenzylamine. Treatment of either the nitroso or the benzoyl derivative of dibenzylamine with lithium diisopropylamide generates a carbanion which reacts with alkyl halides or carbonyl compounds producing α-substitution products in yields of 66–99%. The method also gives good yields of derivatives of N-phenyl-N′-nitroso-piperazine. Attempts to form the carbanion of N-benzoylpiperidine failed.