Stereochemistry of the P–C bond formation in an oxazaphospholidine borane complex

Abstract

The reaction of the 3,4-dimethyl-2,5-diphenyl-1,3,2-oxazaphospholidine borane complex 1 with organometallic reagents involves a stereoselective P–O bond cleavage; the X-ray structures of the starting complex 1 and of the aminophosphine boranes 2a,b, reveal a stereochemistry of the P–C bond formation with a retention of the configuration which is explained by a nucleophilic attack on the less hindered side-face of the pyramidal phosphorus atom.