A Concise Asymmetric Synthesis of cis-2,6-Disubstituted N-Aryl Piperazines via Pd-Catalyzed Carboamination Reactions
journal contributionposted on 16.08.2007, 00:00 by Josephine S. Nakhla, John P. Wolfe
A concise, modular, asymmetric synthesis of cis-2,6-disubstituted piperazines from readily available amino acid precursors is described. The key step in the synthesis is a Pd-catalyzed carboamination of a N1-aryl-N2-allyl-1,2-diamine with an aryl bromide. The products are obtained in 14−20:1 dr, with >97% ee, and the key cyclizations are the first examples of six-membered ring formation via Pd-catalyzed carboamination reactions of unsaturated amines with aryl halides.