Highly Enantioselective Synthesis of Phosphorus-containing ε-Benzosultams via Bifunctional Phosphonium Salt-promoted Hydrophosphonylation.

e-Benzosultam derivatives are potential drug candidates with diverse biological activities. A series of chiral e-benzosultams bearing phosphorus functionalities were synthesized via catalytic asymmetric hydrophosphonylation in the presence of a bifunctional phosphonium salt catalyst. The desired phosphonylation 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 explain the plausible reaction mechanism of this chemical transformation.