title: Efficient visible light photocatalysis of [2+2] enone cycloadditions.
abstract: We report that Ru(bipy)3Cl2 can serve as a visible light photocatalyst for [2+2] enone cycloadditions. A variety of aryl enones participate readily in the reaction, and the diastereoselectivity in the formation of the cyclobutane products is excellent. We propose a mechanism in which a photogenerated Ru(bipy)3+ complex promotes one-electron reduction of the enone substrate, which undergoes subsequent radical anion cycloaddition. The efficiency of this process is extremely high, which allows rapid, high-yielding [2+2] cyclizations to be conducted using incident sunlight as the only source of irradiation.
authors.affiliation: Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Ischay
authors.forename: Mary E
authors.initials: ME
authors.lastname: Anzovino
authors.forename: Juana
authors.initials: J
authors.lastname: Du
authors.forename: Tehshik P
authors.initials: TP
authors.lastname: Yoon