title: Chiral amine/chiral acid as an excellent organocatalytic system for the enantioselective tandem oxa-Michael-aldol reaction.
abstract: The asymmetric tandem oxa-Michael-aldol reaction of salicylic aldehyde derivatives with alpha,beta-unsaturated aldehydes catalyzed by a chiral amine/chiral acid organocatalytic system was investigated. The organocatalytic system of (S)-diphenylpyrrolinol trimethylsilyl ether with chiral shift reagent (S)-Mosher acid presented a synergistic effect in the improvement of reaction performance and offered an efficient steric effect in the transformation. The tandem oxa-Michael-aldol reaction proceeded with high yields (up to 90%) and with excellent ee values (up to 99%) to give the corresponding chromene derivatives. The structure of the chiral ammonium salt formed in situ and the corresponding mechanism were also studied by (1)H NMR.
authors.affiliation: State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Zhejiang University of Technology, Hangzhou, China.
authors.forename: Shu-Ping
authors.initials: SP
authors.lastname: Luo
authors.forename: Zhao-Bo
authors.initials: ZB
authors.lastname: Li
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Wang
authors.forename: Yi
authors.initials: Y
authors.lastname: Guo
authors.forename: Ai-Bao
authors.initials: AB
authors.lastname: Xia
authors.forename: Dan-Qian
authors.initials: DQ
authors.lastname: Xu
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D000588:Amines / Q000737:chemistry*; D002384:Catalysis; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D000447:Aldehydes; D000588:Amines; C116609:3-hydroxybutanal