Carbonylative Suzuki-Miyaura Coupling Reaction of Lactam-, Lactone-, and Thiolactone-derived Enol Triflates for the Synthesis of Unsymmetrical Dienones.

A thorough study of the carbonylative Suzuki-Miyaura cross-coupling reaction of enol triflates with alkenylboronic acids for the synthesis of unsymmetrical dienones is reported. Conditions were found that enabled the coupling of structurally different enol triflates derived from lactams, lactones, and thiolactones (i.e., cyclic ketene aminal, acetal, and thioacetal triflates, respectively) with various alkenylboronic acids at room temperature under 1 atm of CO pressure with 1-5% palladium catalyst; the carbonylated products were obtained in 50-86% overall yields. The methodology allows for a convergent and rapid preparation of substrates useful in conjugate additions and Nazarov reactions