Title: Highly Site Selective Formal [5+2] and [4+2] Annulations of Isoxazoles with Heterosubstituted Alkynes by Platinum Catalysis: Rapid Access to Functionalized 1,3-Oxazepines and 2,5-Dihydropyridines

Author: Wen-Bo Shen,Xin-Yu Xiao,Qing Sun,Bo Zhou,Xin-Qi Zhu,Juan-Zhu Yan,Prof. Dr. Xin Lu,Prof. Dr. Long-Wu Ye

Abstract:

Platinum-catalyzed formal [5+2] and [4+2] annulations of isoxazoles with heterosubstituted alkynes enabled the atom-economical synthesis of valuable 1,3-oxazepines and 2,5-dihydropyridines, respectively. Importantly, this Pt catalysis not only led to unique reactivity dramatically divergent from that observed under Au catalysis, but also proceeded via unprecedented α-imino platinum carbene intermediates.

FULLLINK: http://onlinelibrary.wiley.com/doi/10.1002/ange.201610042/full