Model Guided Development of a Simple Catalytic Method for the Synthesis of Unsymmetrical Stilbenes by Sequential Heck Reactions of Aryl Bromides with Ethylene

摘要

Stilbenes are important and useful structural moieties, but methods for their preparation typically possess numerous inefficiencies. Presented here is a methodology for the two-step, one pot preparation of unsymmetrical stilbenes via sequential Heck reactions. The first Heck reaction with ethylene gas was analysed as a function of temperature and pressure for electronically differentiated naphthyl bromides and modelaided reaction optimization was utilized to define the system. In addition, reactNMR was utilized to determine ethylene solubility in common organic solvents useful for Heck reactions. Finally, an optimized sequential Heck reaction process was developed and applied to a range of substrates allowing for efficient preparation of unsymmetrical stilbenes, including the natural antioxidant, pterostilbene.