Synthesis of Isoxazolines and Oxazines by Electrochemical Intermolecular [2 + 1 + <i>n</i>] Annulation: Diazo Compounds Act as Radical Acceptors
作者:Mingteng Xiong、Xiao Liang、Zhan Gao、Aiwen Lei、Yuanjiang Pan
DOI:10.1021/acs.orglett.9b03306
日期:2019.12.6
Reported herein is an unprecedented synthesis of isoxazolines and oxazines through electrochemical intermolecular annulation of alkenes with tert-butyl nitrite, in which diazo compounds serve as radical acceptors. Notably, [2 + 1 + 2] and [2 + 1 + 3] annulations occur when styrenes and allylbenzenes are used as substrates, respectively. The latter reaction undergoes group migration to form more stable radical, manifesting radical route instead of conventional 1,3-dipolar cycloaddition occurs. Moreover, scale-up experiments suggest the potential application value of these transformations in industry.