title: Synthesis of optically enriched spirocyclic benzofuran-2-ones by bifunctional thiourea-base catalyzed double-Michael addition of benzofuran-2-ones to dienones.
abstract: A highly enantioselective catalytic double-Michael addition reaction of substituted benzofuran-2-ones with divinyl ketones promoted by readily accessible tertiary amine-thiourea Cinchona alkaloids has been developed. A number of optically enriched spirocyclic benzofuran-2-ones were prepared in very good yields (up to 99 %), diastereoselectivities (up to 19:1 d.r.), and very good enantioselectivities (up to 92 % ee). Density functional theory (DFT) calculations were performed to investigate the origin of stereoselectivity.
authors: Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 30071, China. xin_li@nankai.edu.cn
authors: Xin
authors: X
authors: Li
authors: Chen
authors: C
authors: Yang
authors: Jia-Lu
authors: JL
authors: Jin
authors: Xiao-Song
authors: XS
authors: Xue
authors: Jin-Pei
authors: JP
authors: Cheng
mesh_terms: D001572:Benzofurans / Q000138:chemical synthesis* / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D007659:Ketones / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D055620:Optical Phenomena; D013141:Spiro Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D013890:Thiourea / Q000737:chemistry*
chemical_list: D001572:Benzofurans; D007659:Ketones; D013141:Spiro Compounds; D013890:Thiourea