title: Unexpected tandem ylide annulation reaction for controllable synthesis of 2H-chromenes and 4H-chromenes.
abstract: [reaction: see text] An unexpected tetrahydrothiophene-catalyzed ylide annulation reaction, via tandem Michael addition/elimination/substitution, for the controllable synthesis of 2H-chromenes and 4H-chromenes has been developed.
authors.affiliation: State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, PRC.
authors.forename: Long-Wu
authors.initials: LW
authors.lastname: Ye
authors.forename: Xiu-Li
authors.initials: XL
authors.lastname: Sun
authors.forename: Chun-Yin
authors.initials: CY
authors.lastname: Zhu
authors.forename: Yong
authors.initials: Y
authors.lastname: Tang