title: Formal asymmetric catalytic thiolation with a bifunctional catalyst at a water-oil interface: synthesis of benzyl thiols.
abstract: The enantioselective conjugated addition of tritylthiol to in situ generated ortho-quinone methides (o-QMs) is catalyzed by an acid-base bifunctional squaramide organocatalyst. The transformation proceeds with high yield (up to 99 %) and stereoselectivity (up to 97:3 e.r.) using water as solvent under mild conditions. The catalyst system provides a new strategy for the synthesis of optically active benzyl mercaptans. Control experiments suggested that o-QMs are generated by the tertiary amine moiety of the squaramide organocatalyst and that the water-oil biphase is crucial for achieving high reactivity and stereoselectivity.
authors.affiliation: State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023 (China).
authors.forename: Wengang
authors.initials: W
authors.lastname: Guo
authors.forename: Bo
authors.initials: B
authors.lastname: Wu
authors.forename: Xin
authors.initials: X
authors.lastname: Zhou
authors.forename: Ping
authors.initials: P
authors.lastname: Chen
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
authors.forename: Yong-Gui
authors.initials: YG
authors.lastname: Zhou
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.forename: Can
authors.initials: C
authors.lastname: Li
mesh_terms: D000588:Amines / Q000138:chemical synthesis / Q000737:chemistry; D001555:Benzene Derivatives / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D045563:Indolequinones / Q000138:chemical synthesis / Q000737:chemistry*; D009821:Oils / Q000737:chemistry; D013237:Stereoisomerism; D013438:Sulfhydryl Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D000588:Amines; D001555:Benzene Derivatives; D045563:Indolequinones; D009821:Oils; D013438:Sulfhydryl Compounds; D014867:Water; C068040:quinone methide
keywords: asymmetric catalysis; organocatalysis; ortho-quinone methides; thiol addition