Pd-Catalyzed Regioselective (Markovnikov) Addition of Aryl Boronic Acids to Terminal Alkynes of 1,3-Dicarbonyl Compounds and Cyclization/Debenzoylation of Olefinic Dicarbonyl: Access to Arylated Pyran and (E)-4-Methylene-1,6-diphenylhex-5-en-1-one

This Letter outlines palladium-catalyzed regioselective (Markovnikov's) addition of aryl boronic acids to propargyl 1,3-dicarbonyl alkyne to accomplish olefinic/diene 1,3-dicarbonyl compounds without the need for water workup. This methodology showcases remarkable performance with wide-ranging substrate diversity, achieving high yields while employing merely 3 mol % [Pd] alongside a mild KOAc base. Moreover, the utility of dicarbonyl olefins is exemplified through their application in intramolecular cyclization and debenzoylation reactions to access valuable trisubstituted pyran building blocks and (E)-4-methylene-1,6-diphenylhex-5-en-1-one synthesis.

Automated summary

This research presents a selective palladium-catalyzed reaction for the addition of aryl boronic acids to propargyl 1,3-dicarbonyl alkyne without the need for water workup. The method shows high efficiency with a wide range of substrates using only 3 mol% [Pd] and a mild KOAc base. Furthermore, the application of this method in intramolecular cyclization and debenzoylation reactions leads to the synthesis of valuable trisubstituted pyran building blocks and (E)-4-methylene-1,6-diphenylhex-5-en-1-one.