Kuan Tzu-Hsuan, Hou Duen-Ren
Department of Chemistry, National Central University, No. 300 Jhong-Da Road, Jhong-li, Taoyuan 32001, Taiwan.
J Org Chem. 2021 May 7;86(9):6907-6917. doi: 10.1021/acs.joc.1c00294. Epub 2021 Apr 14.
Hydrobromination and oxy-isomerization of (-arylethynyl)benzyl alcohols to yield brominated aryl ketones were achieved with bromotrimethylsilane. The substrate scope suggested that vinyl carbocations, stabilized by the conjugated aryl groups, are the reaction intermediates. 1-Isochromene was also detected by H NMR, and an isolated 1-isochromene was converted to the product when retreated with TMSBr. The formation of 1-isochromene is equivalent to a 6- cyclization and contrasts with the corresponding reactions under basic conditions, in which the 5- process dominated.
使用三甲基溴硅烷实现了（-芳基乙炔基）苄醇的氢溴化和氧异构化反应，生成溴代芳基酮。底物范围表明，由共轭芳基稳定的乙烯基碳正离子是反应中间体。通过1H NMR也检测到了1-异苯并呋喃，当用TMSBr再次处理时，分离得到的1-异苯并呋喃会转化为产物。1-异苯并呋喃的形成相当于一个6-环化反应，这与碱性条件下的相应反应形成对比，在碱性条件下5-环化反应占主导。
