Synthesis of P-stereogenic cyclicphosphinic amides via electrochemically enabled cobalt-catalyzed enantioselective C–H annulation

Abstract

The development of an electrochemical process method for the synthesis of P-chiral phosphine derivatives poses a considerable challenge. Here, we present an electricity-driven cobalt-catalyzed enantioselective C–H annulation of arylphosphinic amides and alkynes, which provides rapid access to P-chiral cyclicphosphorus oxides in good yields with excellent enantioselectivities (48–99% yields, 94–>99% ee). The reaction was compatible with aqueous solvents and proceeded efficiently in a shorter reaction time compared with the previous work using oxidants. The process employs a combination of readily available chiral salicyloxazoline and cobalt acetate tetrahydrate as an inexpensive catalyst. Notably, the kinetic resolution process was also achieved with s factors up to 347.8. Experimental, kinetic and computational studies on cobalta-electrocatalysis provide insights into the catalyst's working mode.