Iwasaki M, Fujii T, Nakajima K, Nishihara Y. Iron-induced regio- and stereoselective addition of sulfenyl chlorides to alkynes by a radical pathway.
Angew Chem Int Ed Engl 2014;
53:13880-4. [PMID:
25319321 DOI:
10.1002/anie.201408121]
[Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Revised: 09/25/2014] [Indexed: 11/09/2022]
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.
Collapse