Amide-Directed Intramolecular Co(III)-Catalyzed C–H Hydroarylation of Alkenes for the Synthesis of Dihydrobenzofurans with a Quaternary Center

The
first example of Cp*Co­(III)-catalyzed intramolecular hydroarylation
of allyl aryl ethers using an amide directing group for the preparation
of 3,3-disubstituted dihydrobenzofurans in high yields is described.
The reaction of the unactivated alkene is completely selective for
the formation of the quaternary center, allowing different substitution
patterns on the aromatic ring and the alkene. The cyclization can
also be extended to the formation of six-membered rings and to N-homoallylindoles.