Highly Regio- and Stereoselective Catalytic Synthesis of Conjugated Dienes and Polyenes

Conjugated dienes and polyenes are
typically synthesized by sequential
introduction of CC bonds. Here, we report a practical and
scalable, catalytic dienylation that is highly regio- and stereoselective
for both CC bonds. The reaction is enabled by a stereoselective
palladium-catalyzed cross-coupling that is preceded by a regioselective
base-induced ring opening of readily available sulfolenes. The dienylation
reaction is particularly useful for the synthesis of synthetically
challenging dienes containing cis double bonds. We also show that
the reaction can serve as a synthetic platform for the construction
of conjugated polyenes.