Selective indium-mediated 1,2,4-pentatrien-3-ylation of carbonyl compounds for the efficient synthesis of vinyl allenols.

A highly selective synthetic method of functionalized vinyl allenols was developed from the reactions of various carbonyl compounds with organoindium reagent in situ generated from indium and 1-bromopent-4-en-2-yne derivatives. Treatment of vinyl allenols with gold catalyst, dienophile, or indium trihalide produced the functionalized dihydrofuran, cyclohexene, or 2-halo-1,3-diene derivatives in good to excellent yields.