title: Iron-induced regio- and stereoselective addition of sulfenyl chlorides to alkynes by a radical pathway.
abstract: The radical addition of the Cl-S σ-bond in sulfenyl chlorides to various C-C triple bonds has been achieved with excellent regio- and stereoselectivity in the presence of a catalytic amount of a common iron salt. The reaction is compatible with a variety of functional groups and can be scaled up to the gram-scale with no loss in yield. As well as terminal alkynes, internal alkynes underwent stereodefined chlorothiolation to provide tetrasubstituted alkynes. Preliminary mechanistic investigations revealed a plausible radical process involving a sulfur-centered radical intermediate via iron-mediated homolysis of the Cl-S bond. The resulting chlorothiolation adducts can be readily transformed to the structurally complex alkenyl sulfides by cross-coupling reactions. The present reaction can also be applied to the complementary synthesis of the potentially useful bis-sulfoxide ligands for transition-metal-catalyzed reactions.
authors.affiliation: Division of Earth, Life, and Molecular Sciences, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushimanaka, Kita-ku, Okayama 700-8530 (Japan).
authors.forename: Masayuki
authors.initials: M
authors.lastname: Iwasaki
authors.forename: Tomoya
authors.initials: T
authors.lastname: Fujii
authors.forename: Kiyohiko
authors.initials: K
authors.lastname: Nakajima
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Nishihara
keywords: alkynes; chlorothiolation; iron; radical reactions; synthetic methods