Nickel-Catalyzed Alkoxy-Alkyl Interconversion with Alkylborane Reagents through C-O Bond Activation of Aryl and Enol Ethers.

A nickel-catalyzed alkylation of polycyclic aromatic methyl ethers as well as methyl enol ethers with B-alkyl 9-BBN and trialkylborane reagents that involves the cleavage of stable C(sp2 )-OMe bonds is described. The transformation has a wide substrate scope and good chemoselectivity profile while proceeding under mild reaction conditions; it provides a versatile way to form C(sp2 )-C(sp3 ) bonds that does not suffer from β-hydride elimination. Furthermore, a selective and sequential alkylation process by cleavage of inert C-O bonds is presented to demonstrate the advantage of this method.