Intramolecular Ketone−Nitrile Reductive Coupling Reactions Promoted by Samarium(II) Iodide

Samarium(II) iodide (SmI2) has been successfully utilized as a reducing agent for the intramolecular coupling of ketones with nitriles. The use of visible light to promote the reductive coupling represents an improvement over previously reported protocols. The procedure also avoids overreduction of the resulting α-hydroxy ketones. Monocyclic, fused bicyclic, and bridged bicyclic α-hydroxy ketones composed of a number of substitution patterns have been synthesized in moderate to excellent yield via this method. A sequential reaction consisting of a nucleophilic acyl substitution followed by a ketyl−nitrile coupling has also been accomplished.