Synthesis and reactivity of boryloxorhodium complexes. Relevance to intermolecular transmetalation from boron to rhodium in Rh-catalyzed reactions

Abstract

The synthesis of a dimeric boryloxorhodium complex having the Rh–O–Bpin scaffold from the reaction of [(cod)Rh(OMe)]₂ or [(cod)Rh(OH)]₂ with an arylboronate has been achieved. The obtained dirhodium complex is converted into mononuclear complex [(cod)Rh(OBpin)(PPh₃)], which reacts with arylboronic acid to afford the complex with an Rh-aryl bond via transmetalation from boron to rhodium. The dimeric boryloxorhodium complex catalyzes the 1,4-addition of arylboronic acid to cyclohexene-2-one.