Materials Research Science and Engineering Center

David Barnes

“Generation of Methylene-coupled Products via Reductive Elimination from an Oxidied Gold(III-III) A-Frame”

David Barnes*, Benjamin Reiner, Casey Wade
Hampton University / Mathematics
Hosted by Casey Wade's Lab

Abstract

Multinuclear gold complexes have received increased attention in organometallic chemistry in the past four decades. These complexes have been used to explore structure and bonding as well as the role of multinuclearity on catalytic and stoichiometric transformations.

We have focused our efforts on binuclear gold complexes bearing phosphorus diylid ligands. These complexes are nucleophilic at gold which allows facile activation of small molecules. Notably, treatment of complex 1 with dibromomethane cleanly affords complex 2 in a 2-center, 4-electron oxidation. Schmidbaur and coworkers have reported that alkylation of complex 2 (Ar = phenyl) affords complex 3 which, upon thermolysis in the solid state, liberates propane and regenerates. While the generation of a methylene inserted product is intriguing, the high temperatures required to effect the transformation (>150 ˚C) would preclude the use of compound 1 as a practical methylene insertion agent. Considering the high barrier to reductive elimination, we hypothesized that increasing the size of the substituents at phosphorus may lower the barrier to reductive elimination by increasing steric congestion around the gold sites. Reducing the barrier to reductive elimination may allow use of these gold complexes for catalytic methylene insertion under mild and safe conditions. Realizing this goal would provide a valuable tool for synthetic chemists. Herein we report our efforts toward the synthesis and reactivity of binuclear gold complexes bearing sterically bulky diylid ligands.

Support

MRSEC REU