Transition-metal-free synthesis of 1,4-benzoxazepinesvia[4+3]-cycloaddition ofpara-quinone methides with azaoxyallyl cations

作者：Zhou, Shuang-Jing; Cheng, Xiao; Hu, Chun-Xia; Xu, Guo-Yong; Xiao, Wen-Jing^*; Xuan, Jun^*

来源：Science China Chemistry, 2021, 64(1): 61-65.

DOI：10.1007/s11426-020-9832-9

• 1
• 4-benzoxazepines
• para-quinone methides
• azaoxyallyl cations
• cycloaddition
• transition-metal-free

A formal [4+3]-cycloaddition reaction ofortho-hydroxyphenyl-substituted para-quinone methides (p-QMs) within-situgenerated azaoxyallyl cations is reported. The reaction occurs under very mild reaction conditions (transition-metal free, room temperature, cheap inorganic base) and provides a very efficient route to a series of biologically important 1,4-benzoxazepine derivatives in good to excellent yields.