Regioselective ring opening of amino acids derived chiral aziridines: an easy access to cis-2,5-disubstituted chiral piperazines†

Abstract

Four-step efficient synthetic strategy for cis-2,5-disubstituted chiral piperazines derived from amino acids based aziridines is described. First report of BF3.OEt2 mediated highly regioselective ring opening of less reactive N-Ts chiral aziridines by α-amino acids methyl ester hydrochloride followed by Mitsunobu cyclization are the key reaction steps. This protocol was used in an attempt to construct the piperazine core framework of natural product (+)- piperazinomycin.