Palladium-catalyzed direct 5-arylation of 1,3-dimethyluracil with aryl bromides: an electrophilic metalation–deprotonation with electrophilic arylpalladium intermediate
作者:Ko Hoon Kim、Hyun Seung Lee、Jae Nyoung Kim
DOI:10.1016/j.tetlet.2011.09.066
日期:2011.11
An efficient method of palladium-catalyzed direct 5-arylation of 1,3-dimethyluracil was developed with a various range of aryl bromides including electron-deficient aryl bromides. 5-Aryluracil derivatives were obtained in moderate to good yields regioselectively most likely via an electrophilic metalation–deprotonation process.
Switching the Regioselectivity of Direct C-H Arylation of 1,3-Dimethyluracil
作者:Miroslava Čerňová、Radek Pohl、Michal Hocek
DOI:10.1002/ejoc.200900586
日期:2009.8
An interesting dichotomy in the regioselectivity and mechanism of directC–Harylation of 1,3-dimethyluracil was observed. Its Pd-catalyzed reactions with diverse aryl halides in the absence of CuI lead preferentially to 5-aryluracils, while reactions in the presence of CuI give 6-aryl derivatives as the major products. Cu-mediated reactions (in the absence of a Pd catalyst) proceed with lower efficiency