title: Markovnikov-Selective Radical Addition of S-Nucleophiles to Terminal Alkynes through a Photoredox Process.
abstract: Direct radical additions to terminal alkynes have been widely employed in organic synthesis, providing credible access to the anti-Markovnikov products. Because of the Kharasch effect, regioselective control for the formation of Markovnikov products still remains a great challenge. Herein, we develop a transition-metal-free, visible light-mediated radical addition of S-nucleophiles to terminal alkynes, furnishing a wide array of α-substituted vinyl sulfones with exclusive Markovnikov regioselectivity. Mechanistic investigations demonstrated that radical/radical cross-coupling might be the key step in this transformation. This radical Markovnikov addition protocol also provides an opportunity to facilitate the synthesis of other valuable α-substituted vinyl compounds.
authors.affiliation: The Institute for Advanced Studies (IAS), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, Hubei, P.R. China.
authors.forename: Huamin
authors.initials: H
authors.lastname: Wang
authors.affiliation: The Institute for Advanced Studies (IAS), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, Hubei, P.R. China.
authors.forename: Qingquan
authors.initials: Q
authors.lastname: Lu
authors.affiliation: The Institute for Advanced Studies (IAS), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, Hubei, P.R. China.
authors.forename: Chien-Wei
authors.initials: CW
authors.lastname: Chiang
authors.affiliation: The Institute for Advanced Studies (IAS), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, Hubei, P.R. China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Luo
authors.affiliation: The Institute for Advanced Studies (IAS), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, Hubei, P.R. China.
authors.forename: Jiufu
authors.initials: J
authors.lastname: Zhou
authors.affiliation: The Institute for Advanced Studies (IAS), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, Hubei, P.R. China.
authors.forename: Guangyu
authors.initials: G
authors.lastname: Wang
authors.affiliation: The Institute for Advanced Studies (IAS), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, Hubei, P.R. China.|Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, P.R. China.
authors.forename: Aiwen
authors.identifier: 0000-0001-8417-3061
authors.initials: A
authors.lastname: Lei
keywords: Markovnikov selectivity; photoredox catalysis; radical addition; radical cross coupling; transition-metal-free synthesis