A Synthetic Methodology from Acetylenic Derivatives

The transition metal catalyzed isomerization reactions of acetylenic derivatives were studied.(E,E)-Conjugated dienones, dienoic esters and dienoic amides were synthesized from correspondingα,β-ynones, 2-ynoic esters and 2-ynoic amides, respectively. 2-Ynols were first isomerized to thecorresponding 2-enones or 2-enals. The reactions can he accomplished simply, in high yield, and stere-oselectively. It is proposed that allenic compounds are initially formed as the main intermediates andthen isomerized further to the products. A convenient and potential useful methodology is provided forthe preparation of important intermediates in the synthesis of natural products.