PALLADIUM CATALYZED-REACTIONS OF PROPARGYL CARBONATES

Carbonates of propargyl alcohol and its functionalized derivatives undergo various palladium-catalyzed reactions under mild neutral conditions. Their reacton with olefins affords 1,2,4-trienes, and 1,2-dien-4-ynes are obtained by the reaction with terminal acetylenes. Reaction with soft carbonucleophiles is a good synthetic method for furans. Also 2-(1-alkynyl)oxiranes react with beta-keto esters to form furans. Allenyl esters (2,3-dienoates) and their derivatives such as alpha-alkylidene-beta-lactams and alkylidenecyclopentenonecarboxylates are obtained by the carbonylation of various functionalized propargyl carbonates. Allenes(1,2-dienes) are formed by the hydrogenolysis with formic acid.