Highly Enantioselective Synthesis of Phosphorus‐Containing ϵ‐Benzosultams by Bifunctional Phosphonium Salt‐Promoted Hydrophosphonylation

ϵ-Benzosultam derivatives are potential drug candidates with diverse biological activities. A series of chiral ϵ-benzosultams bearing phosphorus functionalities was synthesized by catalytic asymmetric hydrophosphonylation in the presence of a bifunctional phosphonium salt catalyst. The desired hydrophosphonylation products were obtained in good yields with high enantioselectivities, and scale-up reactions and further derivations were successfully accomplished. Some control experiments were also conducted to elucidate the plausible reaction mechanism of this chemical transformation.