Rhodium-Catalyzed Carbonylation of 3-Acyloxy-1,4-enynes for the Synthesis of Cyclopentenones

Functionalized cyclopentenones were synthesized by a Rh-catalyzed carbonylation of 3-acyloxy-1,4-enynes, derived from alkynes and α,β-unsaturated aldehydes. The reaction involved a Saucy–Marbet 1,3-acyloxy migration of propargyl esters and a [4 + 1] cycloaddition of the resulting acyloxy substituted vinylallene with CO.