Background

Cross-coupling reactions have become the most widely used in complex organic molecule synthesis for forming carbon-carbon and carbon-element bonds. Most cross-coupling requires the addition of a transition metal catalyst to complete the reaction. A method used ubiquitously throughout industry and research is to employ a Pd(0)-dba precatalyst. However, Pd(0)-dba complexes can produce inconsistent catalytic results, degrade rapidly in solution, and the dba released after activation can interfere with catalysis. There has been development of a Pd(II)- based precatalyst; however, they require basic conditions to be activated and a pre-installation step of a phosphine ligand. Therefore, each precatalyst is specific to the substrates being coupled. There are significant drawbacks to these commonly used precatalyst, signifying a need for a universal palladium precursor that can favor rapid and complete phosphine displacement, and directly enter the cross-coupling catalytic cycle. 

Technology Overview

Researchers have developed a novel and versatile Pd(0) precursor, (DMP)DAB-Pd-MAH, for in situ cross-coupling catalyst preparation. It is also an excellent platform for single-component precatalyst synthesis. This Pd(0) complex has been intelligently designed by stabilizing the Pd(0) source by way of a chelating diazabutadiene (DAB) ligand and maleic anhydride (MAH) as an electron deficient alkene. These complexes are a multifunctional Pd(0) source for optimized cross-coupling reaction screening and scale-up without the drawbacks associated with the most commonly-used Pd(0) source, Pd2dba2.

Benefits

• Good solubility in a range of organic solvents. 
• Excellent solid-state and solution stability.
• Reactions proceed to well-defined Pd(0) products that are easily isolated, providing a way to generate air-stable single component Pd(0) precatalyst when desired. 
• Rapid ligand substitution of the chelating DAB with various phosphines relevant to cross-coupling. 

Applications

• High-throughput reaction screening. 
• Preparative-scale synthesis. 

Opportunity

• Collaborative research 
• Technology licensing