title: N-Heterocyclic carbene-catalyzed [4 + 2] cyclization of α,β-unsaturated carboxylic acids bearing γ-H with isatins: an enantioselective synthesis of spirocyclic oxindole-dihydropyranones.
abstract: An NHC-catalyzed asymmetric [4 + 2] annulation of isatins and α,β-unsaturated carboxylic acids bearing γ-H gave spirocyclic oxindole-dihydropyranones successfully via an in situ activation strategy. This protocol featured easy availability of raw materials, good yields and excellent enantioselectivities (up to 99% ee).
authors.affiliation: School of Chemistry and Chemical Engineering, Jiangsu Key Lab of Green Synthetic Chemistry for Functional Materials, Jiangsu Normal University, Xuzhou, Jiangsu 221116, P R China. csyao@jsnu.edu.cn.
authors.forename: Ling
authors.initials: L
authors.lastname: Zhu
authors.forename: Chenxia
authors.initials: C
authors.lastname: Yu
authors.forename: Tuanjie
authors.initials: T
authors.lastname: Li
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Wang
authors.forename: Yinan
authors.initials: Y
authors.lastname: Lu
authors.forename: Wenjing
authors.initials: W
authors.lastname: Wang
authors.forename: Changsheng
authors.initials: C
authors.lastname: Yao
mesh_terms: D002264:Carboxylic Acids / Q000138:chemical synthesis / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D003500:Cyclization; D006571:Heterocyclic Compounds / Q000737:chemistry*; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry; D007510:Isatin / Q000031:analogs & derivatives / Q000737:chemistry*; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D013141:Spiro Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D002264:Carboxylic Acids; D006571:Heterocyclic Compounds; D007211:Indoles; D013141:Spiro Compounds; C030011:carbene; D007510:Isatin; D008697:Methane