title: N-heterocyclic carbene/Lewis acid strategy for the stereoselective synthesis of spirocyclic oxindole-dihydropyranones.
abstract: Under the cooperative catalysis of NHC/Lewis acid, the mild, straightforward [4 + 2] annulation of α-bromo-α,β-unsaturated aldehydes bearing γ-H with isatin derivatives gave spirocyclic oxindole-dihydropyranones stereoselectively. This approach is particularly attractive due to the concise construction, avoidance of external oxidants, and the potential utilization value of final products in molecular biology and pharmacy.
authors.affiliation: School of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Green Synthetic Chemistry for Functional Materials, Jiangsu Normal University , Xuzhou Jiangsu 221116, P. R. China.
authors.forename: Zhaoxin
authors.initials: Z
authors.lastname: Xiao
authors.forename: Chenxia
authors.initials: C
authors.lastname: Yu
authors.forename: Tuanjie
authors.initials: T
authors.lastname: Li
authors.forename: Xiang-Shan
authors.initials: XS
authors.lastname: Wang
authors.forename: Changsheng
authors.initials: C
authors.lastname: Yao