Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States.
Org Lett. 2017 Dec 1;19(23):6280-6283. doi: 10.1021/acs.orglett.7b02906. Epub 2017 Nov 11.
The direct Pd-catalyzed ortho C-H hydroxylation of benzaldehydes was achieved using 4-chloroanthranilic acid as the transient directing group, 1-fluoro-2,4,6-trimethylpyridnium triflate as the bystanding oxidant, and p-toluenesulfonic acid as the putative oxygen nucleophile. The unusual C-H chlorination and polyfluoroalkoxylation reactions signaled the importance of external nucleophiles to the outcome of Pd(IV) reductive eliminations.
使用 4-氯邻氨基苯甲酸作为瞬态导向基团、1-氟-2,4,6-三甲基吡啶三氟甲磺酸盐作为备用氧化剂以及对甲苯磺酸作为可能的氧亲核试剂，实现了苯甲醛的直接 Pd 催化邻位 C-H 羟化反应。不寻常的 C-H 氯化和多氟烷氧基化反应表明外部亲核试剂对 Pd(IV)还原消除的结果很重要。
