title: Organocatalyzed [3 + 2] Annulation of Cyclopropenones and β-Ketoesters: An Approach to Substituted Butenolides with a Quaternary Center.
abstract: An unprecedented organocatalyzed [3 + 2] annulation of cyclopropenones and β-ketoesters has been developed. This reaction provides a direct approach to highly substituted butenolides with a quaternary center in moderate to good yields. The preliminary mechanism study verified that the enol intermediate is crucial to the reaction outcome and the intermolecular esterification and intramolecular Michael addition process were involved.
authors.affiliation: State Key Laboratory of Natural Medicines and Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University , Nanjing 210009, P. R. China.
authors.forename: Xuanyi
authors.initials: X
authors.lastname: Li
authors.affiliation: State Key Laboratory of Natural Medicines and Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University , Nanjing 210009, P. R. China.
authors.forename: Chunhua
authors.initials: C
authors.lastname: Han
authors.affiliation: State Key Laboratory of Natural Medicines and Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University , Nanjing 210009, P. R. China.
authors.forename: Hequan
authors.identifier: 0000-0003-4865-820X
authors.initials: H
authors.lastname: Yao
authors.affiliation: State Key Laboratory of Natural Medicines and Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University , Nanjing 210009, P. R. China.
authors.forename: Aijun
authors.identifier: 0000-0001-5786-4537
authors.initials: A
authors.lastname: Lin