Abstract:
We disclose a benzylic C-H oxidative coupling reaction with alcohols that proceeds through a synergistic deprotonation, halogenation and substitution sequence. The combination of tert-butoxide bases with 2-halothiophene halogen oxidants enables the first general protocol for generating and using benzyl halides through a deprotonative pathway. In contrast to existing radical-based pathways for C-H functionalization, this process is guided by C-H acidity trends. This gives rise to new synthetic capabilities, including the ability to functionalize diverse methyl(hetero)arenes, tolerance of oxidizable and nucleophilic functional groups, precision site-selectivity for polyalkylarenes and use of a double C-H etherification process to controllably oxidize methylarenes to benzaldehydes.
摘要:
我们公开了通过协同去质子化与醇进行的苄基C-H氧化偶联反应,卤化和取代顺序。叔丁醇碱与2-卤代噻吩卤素氧化剂的组合使得能够通过去质子途径产生和使用苄基卤化物的第一个通用方案。与现有的基于自由基的C-H官能化途径相反,这个过程是由C-H酸度趋势指导的。这就产生了新的合成能力,包括官能化多种甲基(杂)芳烃的能力,对可氧化和亲核官能团的耐受性,聚烷基芳烃的精确位置选择性以及使用双C-H醚化工艺将甲基芳烃可控地氧化为苯甲醛。