Cu-catalyzed asymmetric conjugate reduction of β-substituted α,β-unsaturated phosphonates: an efficient synthesis of optically active β-stereogenic alkylphosphonates

A series of chiral alkylphosphonates bearing β-stereogenic center were synthesized in good enantioselectivities (up to 95% ee) via the CuH-catalyzed asymmetric conjugate reduction of β-substituted α,β-unsaturated phosphonates under optimal conditions using Cu(OAc)2·H2O as the copper source, (R)-SEGPHOS as the ligand, PMHS as the siloxane, and t-BuOH as the additive.