The Palladium nanoclusters (NCs)-catalyzed carbon-carbon bond-forming reaction has emerged as a powerful tool in organic synthesis and has been intensively studied over the past few decades. Recently, a series of gold NC-catalyzed carbon-carbon bond formation has also been introduced even though contamination by PPB levels of palladium impurities has caused debate. Besides the development of gold and palladium NCs, new strategies for the design of gold-based bimetallic catalysts have subsequently been introduced. These burgeoning strategies are remarkable for achieving reaction under ambient conditions, with unique selectivity, and high activity. Among the various bimetallic NCs, Au/Pd has attracted a great deal of attention because of its superior catalytic activities in various types of reaction. In attempts to rationalize the synergistic effects observed with these catalysts, two major factors have been suggested, the ensemble effect and the ligand effect and these effects have been well documented in recently published reviews. This account provides an overview of recent developments in the use of gold-palladium bimetallic NCs for C-X bond activation. A specific objective is to demonstrate the effect of inclusion of Au as nearest heteroatom in the Au/Pd alloy in C-X bond activation from the viewpoint of both experimental observations and quantum chemical calculations.
2015 The Society of Synthetic Organic Chemistry, Japan