Efficient and selective Palladium-catalyzed Telomerization of 1,3-Butadiene with Carbon Dioxide

A more efficient telomerization of 1,3-butadiene with carbon dioxide leading to the valuable δ-lactone 1 (3-ethylidene-6-vinyltetrahydro-2H-pyran-2-one) is reported. The key to success is the use of a palladium/TOMPP-catalyst system (TOMPP=tris-(o-methoxyphenyl)-phosphine), which provided under optimal conditions significantly increased yields of the desired product and improved catalyst turnover numbers (TON=1500).