Chelation-assisted transformation: Synthesis of 1,4-dicarboxylate esters by the Rh-catalyzed carbonylation of internal alkynes with pyridin-2-ylmethanol

摘要

The reaction of internal alkynes 1 with CO and pyridin-2-ylmethanol (2) in the presence of Rh4(CO) 12 results in a double-hydroesterification leading to 1,4-dicarboxylate esters 3. The reaction does not proceed via two consecutive hydroesterifications of alkynes, but the intermediacy of ketene intermediates is proposed. The coordination of the pyridine nitrogen in 2 to rhodium is essential for the reaction to proceed.