Sonogashira Cross‐Coupling Reaction of Bromocyanofluoro Pyridine Compounds: Access to 5‐ and 6‐Alkynylfluoropyridinamidoximes Scaffolds

We disclose a general two-step procedure to access hitherto unknown and under explored 5- 6-alkynyl-3-fluoro-2-pyridinamidoximes from 6-bromo-3-fluoro-2-cyanopyridines wide range of easily available bench-stable terminal alkynes, using Sonogashira cross-coupling, as the first step. The generation polar amidoxime group is realized at late stage upon treatment alkynylfluorocyanopyridine by hydroxylamine. This mild operationally simple room temperature process compatible with enantiopure chiral substrates various functionality including free alcohols, unprotected CBz-protected amines, acetonides, benzyl ethers, amide, imide, di-substituted alkynes strained saturated heterocycles.