Rhodium-Catalyzed Borylation of Aryl 2-Pyridyl Ethers through Cleavage of the Carbon–Oxygen Bond: Borylative Removal of the Directing Group
作者:Hirotaka Kinuta、Mamoru Tobisu、Naoto Chatani
DOI:10.1021/ja511622e
日期:2015.2.4
diboron reagent results in the formation of arylboronic acid derivatives via activation of the C(aryl)-O bonds. The straightforward synthesis of 1,2-disubstituted arenes was enabled through catalytic ortho C-H bond functionalization directed by the 2-pyridyloxy group followed by substitution of this group with a boryl group. Several control experiments revealed that the presence of a sp(2) nitrogen
Palladium-Catalyzed Oxidative Olefination of Phenols Bearing Removable Directing Groups under Molecular Oxygen
作者:Bin Liu、Huai-Zhi Jiang、Bing-Feng Shi
DOI:10.1021/jo4027403
日期:2014.2.7
An efficient Pd(II)-catalyzed oxidative olefination of phenols bearing removable directing groups with molecular oxygen as the sole oxidant has been developed. This reaction protocol provides an efficient and robust synthetic tool for the synthesis of o-alkenyl phenols under mild conditions.
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.