N- and O-arylation reactions of pyridin-2-ones as ambidentnucleophiles have been achieved with diaryliodonium salts on the basis of base-dependent chemoselectivity. In the presence of N,N-diethylaniline in fluorobenzene, pyridin-2-ones were very selectively converted to N-arylated products in high yields. On the other hand, the O-arylation reactions smoothly proceeded with the use of quinoline in chlorobenzene
Palladium-Catalyzed Aromatic C–H Bond Nitration Using Removable Directing Groups: Regiospecific Synthesis of Substituted <i>o</i>-Nitrophenols from Related Phenols
作者:Wei Zhang、Jian Zhang、Shaobo Ren、Yunkui Liu
DOI:10.1021/jo502145v
日期:2014.12.5
A general and regiospecific transformation of substituted phenols into the related o-nitrophenols has been achieved via a three-step process involving the palladium-catalyzed chelation-assisted ortho-C–H bond nitration as the key step. In the process, 2-pyridinyloxy groups act as removable directing groups for the palladium-catalyzed ortho-nitration of substituted 2-phenoxypridines, and they can be
chlorination of phenol derivatives using catalytic amounts of palladium acetate that is amenable to the late-stage chlorination of diflufenican and estrone. The 2-pyridine group allows for a highly efficient palladium-catalyzed chlorination and sequential ortho C–H functionalization reaction of phenol derivatives to produce a variety of symmetrical and unsymmetrical 2,4,6-trisubstituted phenols.