Trimethylphosphate as a Methylating Agent for Cross Coupling: A Slow-Release Mechanism for the Methylation of Arylboronic Esters.

ABSTRACT: A methyl group on an arene, despite its small size, can have a profound influence on biologically active molecules. Typical methods to form a methylarene involve strong nucleophiles or strong and often toxic electrophiles. We report a strategy for a new, highly efficient, copper and iodide co-catalyzed methylation of aryl- and heteroarylboronic esters with the mild, nontoxic reagent trimethylphosphate, which has not been used previously in coupling reactions. We show that it reacts in all cases tested in yields that are higher than those of analogous copper-catalyzed reactions of MeOTs or MeI. The combination of C-H borylation and this methylation with trimethylphosphate provides a new approach to the functionalization of inert C-H bonds and is illustrated by late-stage methylation of four

SUBMITTER: He ZT 

PROVIDER: S-EPMC6827333 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature