title: Phosphine-Catalyzed (4 + 1) Annulation of o-Hydroxyphenyl and o-Aminophenyl Ketones with Allylic Carbonates: Syntheses and Transformations of 3-Hydroxy-2,3-Disubstituted Dihydrobenzofurans and Indolines.
abstract: A phosphine-catalyzed (4 + 1) annulation reaction of o-hydroxyphenyl and o-aminophenyl ketones with ester-modified allylic carbonates has been developed, providing a facile and efficient method to synthesize functionalized 2,3-disubstituted dihydrobenzofurans and indolines. Under mild conditions and in the catalysis of PPh3 (20 mol %), the reactions of o-hydroxyphenyl or o-aminophenyl ketones readily furnish highly functionalized 3-hydroxy-2,3-disubstituted dihydrobenzofurans or 3-hydroxy-2,3-disubstituted indolines in 40-99% yields with generally high diastereoselectivity. To further expand the utility of this annulation reaction to the synthesis of functionalized benzofurans and indoles, the CuSO4-promoted chemical transformations of the annulation products have also been studied.
authors.affiliation: The State Key Laboratory of Elemento-Organic Chemistry and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University , Tianjin 300071, P. R. China.
authors.forename: Zifeng
authors.initials: Z
authors.lastname: Qin
authors.affiliation: The State Key Laboratory of Elemento-Organic Chemistry and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University , Tianjin 300071, P. R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: The State Key Laboratory of Elemento-Organic Chemistry and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University , Tianjin 300071, P. R. China.
authors.forename: Danyang
authors.initials: D
authors.lastname: Wang
authors.affiliation: The State Key Laboratory of Elemento-Organic Chemistry and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University , Tianjin 300071, P. R. China.
authors.forename: Zhengjie
authors.initials: Z
authors.lastname: He