Studies On Novel Palladium-catalyzed C-H Bond Halogenation

Carbon halogen bonds are widely found as key building blocks in organic chemistry.Aromatic halides are ubiquitous coupling partners in various cross-coupling reactions.Last decade has wittness the great advance in the transition-metal catalyzed C-H bond functionalization,among them C-halo bond construction via C-H bond activation has also been extensively studied.Directing group assisted C-H bond functionalization features in good selectivity,high atom-economy and environmental friendliness.This dissertation disclosed two novel catalytic systems for the construction of carbon halogen bond via C-H bond activation strategy as follows.1.A novel C-H bond fluorination in a combined Pd?OAc?₂/NO₃^-system was developed.The catalytic processwas initiated by an in situ generated cationic[Pd?NO₃?]⁺and featured in highly selectivity and broad substrate scope.Notably,highy mono-/di-fluorination selectivity was achieved by using different kinds of fluorinating agents.2.An ortho C-H bond halogenation of O-methyl oximes was developed by using CH₂Cl₂ or CH₂Br₂ as novel halogen sources.The present halogenation method features in mild reaction conditions and are markably broad substrate scope.