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).