title: Synthesis of 3-Sulfenylated Coumarins: BF3·Et2O-Mediated Electrophilic Cyclization of Aryl Alkynoates Using N-Sulfanylsuccinimides.
abstract: A simple and efficient metal-free sulfenylation/cyclization of aryl alkynoates has been developed, obtaining various 3-sulfenylated coumarins in moderate to excellent yields. In the presence of BF3·Et2O, the stable and readily accessible N-sulfanylsuccinimides were employed as electrophiles to induce the 6-endo-dig electrophilic cyclization of alkynoates. The reaction using substrates bearing a methoxy group on the phenoxy ring proceeded in an exclusively distinct pathway via either ipso sulfenylcyclization or sulfenylation of the phenoxy ring depending on the different locations of the methoxy substituent. The resulting 3-sulfenylated coumarins can be readily transformed to 3-sulfinylated or 3-sulfonylated coumarins under different oxidation conditions.
authors.affiliation: College of Chemistry and Chemical Engineering, and ‡Department of Student Affairs, Taiyuan University of Technology , Taiyuan 030024, P. R. China.
authors.forename: Wen-Chao
authors.initials: WC
authors.lastname: Gao
authors.affiliation: College of Chemistry and Chemical Engineering, and ‡Department of Student Affairs, Taiyuan University of Technology , Taiyuan 030024, P. R. China.
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
authors.affiliation: College of Chemistry and Chemical Engineering, and ‡Department of Student Affairs, Taiyuan University of Technology , Taiyuan 030024, P. R. China.
authors.forename: Bing
authors.initials: B
authors.lastname: Zhang
authors.affiliation: College of Chemistry and Chemical Engineering, and ‡Department of Student Affairs, Taiyuan University of Technology , Taiyuan 030024, P. R. China.
authors.forename: Xing
authors.initials: X
authors.lastname: Li
authors.affiliation: College of Chemistry and Chemical Engineering, and ‡Department of Student Affairs, Taiyuan University of Technology , Taiyuan 030024, P. R. China.
authors.forename: Wen-Long
authors.initials: WL
authors.lastname: Wei
authors.affiliation: College of Chemistry and Chemical Engineering, and ‡Department of Student Affairs, Taiyuan University of Technology , Taiyuan 030024, P. R. China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Liu
authors.affiliation: College of Chemistry and Chemical Engineering, and ‡Department of Student Affairs, Taiyuan University of Technology , Taiyuan 030024, P. R. China.
authors.forename: Jun
authors.initials: J
authors.lastname: Tian
authors.affiliation: College of Chemistry and Chemical Engineering, and ‡Department of Student Affairs, Taiyuan University of Technology , Taiyuan 030024, P. R. China.
authors.forename: Hong-Hong
authors.initials: HH
authors.lastname: Chang