Rhodium‐Catalyzed Asymmetric Access to P‐Chiral Triarylphosphine Oxides via Insertion of P─H Bonds into Diazonaphthoquinones

Abstract

Abstract While significant progress has been made in the enantioselective insertion of carbenes into heteroatom‐hydrogen bonds, this chemistry is restricted to the construction of carbon‐based chirality. The asymmetric insertion of carbenes into P─H that delivers P‐chiral products remains untouched. Rhodium(I)‐catalyzed enantioselective synthesis of P‐chiral triarylphosphine oxides via asymmetric C─P coupling of a secondary phosphine oxide (SPO) with diazonaphthoquinone is herein reported. Driven by aromatization, this protocol affords a variety of P‐chiral triarylphosphine oxides tethered to a 2‐naphthol functionality in excellent enantioselectivity by following a kinetic resolution reaction pattern. The diverse synthetic and catalytic applications of the P‐chiral products highlight the value of this method, even though the derivatized trivalent chiral phosphine bears a rather low barrier of racemization.