Mechanism of iridium-catalysed branched-selective hydroarylation of vinyl ethers: a computational study

The iridium-catalysed branched-selective hydroarylation of vinyl ethers represents a rare example of the branched-selective hydroarylation involving the non-styrene-type alkenes. Herein, we report our DFT calculations on the mechanism of this reaction. The results show that after C-H oxidative addition, instead of the widely accepted Chalk-Harrod type mechanism, the branched-selective hydroarylation may proceed through an unconventional modified Chalk-Harrod type mechanism, involving the migratory insertion into the Ir-C bond and C-H reductive elimination. Both steric and electronic effects of the alkoxy group were found to account for the complete branched selectivity.