title: Enantioselective cascade double Michael addition of 3-nitro-2H-chromenes and acyclic enones: efficient synthesis of functionalized tricyclic chroman derivatives.
abstract: An efficient protocol for the asymmetric construction of enantiomerically enriched tetrahydro-6H-benzo[c]chromenes and their derivatives has been developed. The corresponding products were obtained by the cascade double Michael addition of 3-nitro-2H-chromenes and their derivatives with α,β-unsaturated ketones catalyzed by a combination of a quinine-derived primary amine and benzoic acid. Through this methodology, the desired products could be obtained in moderate to good yields (up to 90%), with excellent diastereoselectivities (up to >25 : 1 dr) and moderate to excellent enantioselectivities (up to 95% ee).
authors.affiliation: School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing 100081, People's Republic of China. dudm@bit.edu.cn.
authors.forename: Jun-Hua
authors.initials: JH
authors.lastname: Li
authors.forename: Da-Ming
authors.initials: DM
authors.lastname: Du
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D001578:Benzopyrans / Q000138:chemical synthesis* / Q000737:chemistry*; D060326:Chemistry Techniques, Synthetic; D007659:Ketones / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000475:Alkenes; D001578:Benzopyrans; D007659:Ketones