Synthesis of E -Dienyl Esters Using Acetylene as C2 Synthon.

The stereoselective synthesis of dienyl esters with high atom- and step-economy has been largely unexplored. Herein, we report an efficient approach for the synthesis of E -dienyl esters via rhodium catalysis using carboxylic acid and acetylene as C2 synthon through the cascade of cyclometalation and C-O coupling. This protocol features mild conditions, excellent functional group tolerance, and exclusive E -stereoselectivity and utility in the late-stage modification of pharmaceuticals and natural products.