Efficient Palladium‐Catalyzed Carbonylation of 1,3‐Dienes: Selective Synthesis of Adipates and Other Aliphatic Diesters
Ji Yang, Jiawang Liu, Yao Ge, Weiheng Huang, Francesco Ferretti, Helfried Neumann, Haijun Jiao, Robert Franke, Ralf Jackstell, Matthias Beller
Abstract
The dicarbonylation of 1,3-butadiene to adipic acid derivatives offers the potential for a more cost-efficient and environmentally benign industrial process. However, the complex reaction network of regioisomeric carbonylation and isomerization pathways, make a selective and direct transformation particularly difficult. Here, we report surprising solvent effects on this palladium-catalysed process in the presence of 1,2-bis-di-tert-butylphosphin-oxylene (dtbpx) ligands, which allow adipate diester formation from 1,3-butadiene, carbon monoxide, and methanol with 97 % selectivity and 100 % atom-economy under scalable conditions. Under optimal conditions a variety of di- and triesters from 1,2- and 1,3-dienes can be obtained in good to excellent yields.