Efficient synthesis of styrene derivatives through ethenolysis of renewable propenylbenzenes

Functionalized styrenes were obtained by the ethenolysis of renewable 1-propenylbenzenes in a very efficient synthetic pathway. Some of the products are valuable food & flavor ingredients (4-vinylguaiacol) or locust pheromone (4-vinylanisole). The catalysts employed were ruthenium-alkylidene complexes bearing a N-heterocyclic carbene as a ligand, which bulkiness proved to be important for the catalysis output. The judicious choice the reaction conditions was critical to enable near quantitative yields under mild conditions in short reaction times. More strikingly, the catalyst load could be reduced to 0.01 mol%, keeping good conversion and selectivity.

Automated summary

Functionalized styrenes were synthesized via ethenolysis of renewable 1-propenylbenzenes using ruthenium-alkylidene complexes with a N-heterocyclic carbene ligand as catalysts, where the bulkiness of the ligand proved to be crucial for catalysis efficiency. Careful selection of reaction conditions was essential for achieving near quantitative yields under mild conditions in short reaction times. Notably, the catalyst load could be decreased to 0.01 mol% while maintaining good conversion and selectivity.