title: N-heterocyclic carbene catalyzed cyclocondensation of α,β-unsaturated carboxylic acids: enantioselective synthesis of pyrrolidinone and dihydropyridinone derivatives.
abstract: The catalytic cyclocondensation of in situ activated α,β-unsaturated carboxylic acids was developed. N-heterocyclic carbenes efficiently catalyzed the generation of α,β-unsaturated acyl azolium intermediates from α,β-unsaturated carboxylic acids via in situ generated mixed anhydrides for the enantioselective [3+2] and [3+3] cyclocondensation with α-amino ketones and alkyl(aryl)imines, respectively. The corresponding pyrrolidinones and dihydropyridinones were isolated in good yields with high to excellent enantioselectivities.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China).
authors.forename: Xiang-Yu
authors.initials: XY
authors.lastname: Chen
authors.forename: Zhong-Hua
authors.initials: ZH
authors.lastname: Gao
authors.forename: Chun-Yu
authors.initials: CY
authors.lastname: Song
authors.forename: Chun-Lin
authors.initials: CL
authors.lastname: Zhang
authors.forename: Zhi-Xiang
authors.initials: ZX
authors.lastname: Wang
authors.forename: Song
authors.initials: S
authors.lastname: Ye
keywords: N-heterocyclic carbenes; cyclization; heterocycles; organocatalysis; synthetic methods