Ammonium Salt-Catalyzed Highly Practical <i>Ortho</i>-Selective Monohalogenation and Phenylselenation of Phenols: Scope and Applications
作者:Xiaodong Xiong、Ying-Yeung Yeung
DOI:10.1021/acscatal.8b00327
日期:2018.5.4
An ortho-selective ammonium chloride salt-catalyzed direct C–H monohalogenation of phenols and 1,1′-bi-2-naphthol (BINOL) with 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) as the chlorinating agent has been developed. The catalyst loading was low (down to 0.01 mol %) and the reaction conditions were very mild. A wide range of substrates including BINOLs were compatible with this catalytic protocol. Chlorinated
Nucleophilic para-fluorination of (R,S)-1,1′-Bi-5,6,7,8-tetrahydro-2-naphthol (and its monoacetate) with C6H5J(OCOCF3)2− pyridinium polyhydrogen fluoride yields atropoisomericfluorocyclohexadienones.
A new multigram synthesis of chiral (S)-H-4-BINOL and its derivatives in moderate to high yield (up to 83% total yield) via monoesterification of (S)-BINOL, hydrogenation, and saponification reaction was described. The two new monomethylated (S)-H-4-BINOL obtained may be useful materials in asymmetric catalysis.