A meta-terarylphosphine ligand, Cy*Phine, was developed and demonstrated previously to provide exceptionally high product yield for Pd-catalyzed copper-free Sonogashira cross-coupling across a variety of substrates, compared with other ligands such as biarylphosphines and fluorenylphosphines. We present results of a computational study, on the mechanism of action of Pd-Cy*Phine, and related congeners. The improved catalytic performance was found to be attributable to the third phenyl ring (Ring 3) in the three-ring scaffold of the phosphine, hindering substrate addition to the second ring (Ring 2) through dearomative rearrangement, and thus preventing transformation and depletion of the active catalyst. In addition, alternatives in ligand design that could be effective in Pd-catalyzed cross-coupling reactions are proposed.

Pd-Cy*Phine catalyzed copper-free sonogashira cross-coupling: Mechanism and insights from electronic structure calculations

251st National Meeting (2016)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.