Unraveling innate substrate control in site-selective palladium-catalyzed C-H heterocycle functionalization.

ABSTRACT: Understanding the regioselectivity of C-H activation in the absence of directing groups is an important step towards the design of site-selective C-H functionalizations. The Pd(ii)-catalyzed direct arylation of chromones and enaminones provides an intriguing example where a simple substitution leads to a divergence in substrate-controlled site-selectivity. We describe computational and experimental studies which reveal this results from a switch in mechanism and therefore the selectivity-determining step. We present computational results and experimentally measured kinetic isotope effects and labelling studies consistent with this proposal. The C-H activation of these substrates proceeds via a CMD mechanism, which favors more electron rich positions and therefore displays a pronounc

SUBMITTER: Choi H 

PROVIDER: S-EPMC6013790 | biostudies-literature | 2016 Jun

REPOSITORIES: biostudies-literature