From Tetrahydrofurans to Tetrahydrobenzo[ d]oxepines via a Regioselective Control of Alkyne Insertion in Rhodium-Catalyzed Arylative Cyclization.

The formation of chiral 5- and 7-membered tetrahydrofurans and tetrahydrobenzo[ d]oxepines is achieved via arylative cyclization of simple O-tethered alkyne-enoates in the presence of arylboronic acids and chiral dienes-rhodium catalyst under mild conditions. Access to such structures was achieved via a simple switch in the regioselectivity of the alkyne insertion thanks to a proper choice of the alkyne substituent.