Organocatalyzed Asymmetric Dearomative [3+2] Annulation of Electron‐Deficient 2‐Nitrobenzo Heteroarenes with 3‐Isothiocyanato Oxindoles
Pei‐Hao Dou, Yan Chen, Yong You, Zhen‐Hua Wang, Jian‐Qiang Zhao, Ming‐Qiang Zhou, Wei‐Cheng Yuan
Abstract
Abstract An organocatalyzed asymmetric dearomative [3+2] annulation reaction of electron‐deficient 2‐nitrobenzo heteroarenes including 2‐nitrobenzofurans, 2‐nitrobenzothiophenes and 2‐nitroindoles with 3‐isothiocyanato oxindoles was developed. With a multiple hydrogen‐bonding bifunctional thiourea as the catalyst, the reaction displays broad substrate scope and provides an access to structurally diverse polycyclic spirooxindoles containing three contiguous stereogenic centers in high yields with good diastereo‐ and enantioselectivities (up to 99% yield, 94:6 dr, and 97% ee). This organocatalysis protocol is able to afford the products with complementarily diastereoselectivity versus the previous work with transition metal catalysis. magnified image