N-Heterocyclic Carbene Catalytic [4 + 2] Cyclization of 3-Alkylenyloxindoles with Enals: γ-Carbon Activation for Enantioselective Assembly of Spirocarbocyclic Oxindoles.
The ubiquitous structure of all-carbospirocyclic oxindoles makes the development of new methods for their enantioselective and stereoselective synthesis a significant ongoing challenge. Herein, we disclose a formal [4 + 2] annulation through N-heterocyclic carbene (NHC) catalysis for highly enantioselective synthesis of intriguing spirocarbocyclic oxindoles in the presence of Lewis acids. This protocol features good substrates tolerance, good yields, and excellent diastereoselectivities and enantioselectivities (up to 97% ee) under mild conditions.
State Key Laboratory of Natural Medicines and Department of Medicinal Chemistry, China Pharmaceutical University , 24 Tong Jia Xiang, Nanjing, Jiangsu 210009, P. R. China.|Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , 555 Zu Chong Zhi Road, Shanghai 201203, P. R. China.
Hong
H
Yao
Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , 555 Zu Chong Zhi Road, Shanghai 201203, P. R. China.
Yu
Y
Zhou
State Key Laboratory of Natural Medicines and Department of Medicinal Chemistry, China Pharmaceutical University , 24 Tong Jia Xiang, Nanjing, Jiangsu 210009, P. R. China.|Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , 555 Zu Chong Zhi Road, Shanghai 201203, P. R. China.
Xia
X
Chen
State Key Laboratory of Natural Medicines and Department of Medicinal Chemistry, China Pharmaceutical University , 24 Tong Jia Xiang, Nanjing, Jiangsu 210009, P. R. China.|Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , 555 Zu Chong Zhi Road, Shanghai 201203, P. R. China.
Pengfei
P
Zhang
State Key Laboratory of Natural Medicines and Department of Medicinal Chemistry, China Pharmaceutical University , 24 Tong Jia Xiang, Nanjing, Jiangsu 210009, P. R. China.
Jinyi
J
Xu
State Key Laboratory of Natural Medicines and Department of Medicinal Chemistry, China Pharmaceutical University , 24 Tong Jia Xiang, Nanjing, Jiangsu 210009, P. R. China.|Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , 555 Zu Chong Zhi Road, Shanghai 201203, P. R. China.
Hong
H
Liu