Addition of Bifunctional Organoboron Reagents to Strained Alkenes. Carbon−Carbon Bond Formation with Rh(I) Catalysis in Aqueous Media

Arylboronate esters bearing a pendant Michael-type acceptor olefin undergo transmetalation with a rhodium-based catalytic complex to generate a functionalized organorhodium intermediate that can cyclize onto strained olefins in good to excellent yields. The catalytic system involves the use of an electron-rich, sterically bulky ligand to stabilize the organorhodium intermediate and reduce the incidence of protodeboronation in aqueous media.