A general copper-catalysed enantioconvergent radical Michaelis–Becker-type C(sp³)–P cross-coupling

The Michaelis–Becker reaction of H-phosphonates with alkyl halides represents an ideal means for synthesizing alkyl phosphorous compounds. However, the enantioconvergent conversion of racemic alkyl halides into α-chiral alkyl phosphorous compounds in this reaction is an insurmountable challenge because of the inherent S2 mechanism. Here we disclose a copper-catalysed enantioconvergent radical Michaelis–Becker-type C(sp )–P cross-coupling. Key to the success of this reaction is the use of multidentate chiral anionic ligands for enhancing the reducing capability of the copper catalyst to favour a stereoablative radical pathway over a stereospecific S2-type process. Moreover, the ligand architecture is also able to assist the robust association of copper species with alkyl radicals over H-phosphonates, therefore exerting remarkable chemo- and enantioselectivity. This protocol covers a range of (hetero)benzyl-, propargyl- and α-aminocarbonyl alkyl bromides and chlorides. When allied with follow-up transformations, this method provides a versatile platform for valuable α-chiral alkyl phosphorous building blocks and drug leads. [Figure not available: see fulltext.]