title: An enantioselective biginelli reaction catalyzed by a simple chiral secondary amine and achiral brønsted acid by a dual-activation route.
abstract: An enantioselective Biginelli reaction that proceeds by a dual-activation route has been developed by using a combined catalyst of a readily available trans-4-hydroxyproline-derived secondary amine and a Brønsted acid. Aromatic, heteroaromatic, and fused-ring aldehydes were found to be suitable substrates for this multicomponent reaction. The corresponding dihydropyrimidines were obtained in moderate-to-good yields with up to 98 % ee under mild conditions. Based on the experimental results and the observed absolute configurations of the products, a plausible transition state has been proposed to explain the origin of the activation and the asymmetric induction.
authors.affiliation: Key Laboratory of Green Chemistry & Technology (Sichuan University), Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China.
authors.forename: Junguo
authors.initials: J
authors.lastname: Xin
authors.forename: Lu
authors.initials: L
authors.lastname: Chang
authors.forename: Zongrui
authors.initials: Z
authors.lastname: Hou
authors.forename: Deju
authors.initials: D
authors.lastname: Shang
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Liu
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Feng
mesh_terms: D000090:Acetoacetates / Q000737:chemistry; D000588:Amines / Q000737:chemistry*; D001547:Benzaldehydes / Q000737:chemistry; D002384:Catalysis; D015394:Molecular Structure; D011743:Pyrimidines / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism; D014269:Trifluoroacetic Acid / Q000737:chemistry*; D014508:Urea / Q000737:chemistry
chemical_list: D000090:Acetoacetates; D000588:Amines; D001547:Benzaldehydes; D011743:Pyrimidines; D014508:Urea; D014269:Trifluoroacetic Acid; C024840:ethyl acetoacetate