Pd‐Catalyzed Dienylation of Propargylic Esters Enabling Highly Stereoselective Synthesis of Danishefsky‐Type Trisubstituted Dienes

Comprehensive Summary The stereochemical synthesis of highly substituted Danishefsky‐type dienes remains unsolved in organic chemistry. We describe a simple and efficient approach for the stereoselective synthesis of Danishefsky‐type trisubstituted dienes from readily available propargylic esters via Pd‐catalyzed dienylation reaction through the key intermediate metallacyclobutene in a regio‐, chemo‐ and stereoselective fashion. This method facilitates a broad range of challenging trisubstituted dienes with a high level of stereocontrol. The synthetic utilities of oxygenated trisubstituted dienes have been demonstrated by the downstream chemistry, which notably undergoes Diels‐Alder reaction with a variety of electron‐deficient dienophiles to furnish multisubstituted cyclohexenes in good yields with excellent stereoselectivity.