title: Organocatalyzed Michael-Michael cascade reaction: asymmetric synthesis of polysubstituted chromans.
abstract: An enantioselective cascade Michael-Michael reaction between chalcones enolates and nitromethane catalyzed by a bifunctional thiourea is developed. This reaction provides a mild but efficient approach to chiral benzopyrans bearing three consecutive stereocenters in high yields with excellent stereoselectivities, and the benzopyrans can be easily transformed to the corresponding tricyclic product.
authors.affiliation: State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, PR China.
authors.forename: Zhen-Xin
authors.initials: ZX
authors.lastname: Jia
authors.forename: Yong-Chun
authors.initials: YC
authors.lastname: Luo
authors.forename: Xi-Na
authors.initials: XN
authors.lastname: Cheng
authors.forename: Peng-Fei
authors.initials: PF
authors.lastname: Xu
authors.forename: Yu-Cheng
authors.initials: YC
authors.lastname: Gu
mesh_terms: D002384:Catalysis; D002839:Chromans / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D013890:Thiourea / Q000737:chemistry*
chemical_list: D002839:Chromans; D013890:Thiourea