Regio- and stereoselective preparation of dienylcarboxylic acids and dienylphosphonic esters using a (Z)-alkenyl sulfone-titanocene(II) system

Titanocene(II)-promoted alkenylation of functionalized alkynes with (Z)-alkenyl sulfones proceeded with high regio- and stereoselectivity to produce functionalized dienes. Conjugated dienylcarboxylic acids and dienylphosphonic esters were obtained using acetylenic lithium carboxylates and dialkyl phosphonates as starting materials.