Direct synthesis of α,ω-dicarboxylic acids via dicarbonylation of cyclic ethers

α,ω-Dicarboxylic acids are important intermediates for the preparation of polyamides , polyesters and polyurethanes . However, their production pathways are limited and usually suffer from low efficiency and environmental problems. Here, we report an innovative approach to synthesize C+2 dicarboxylic acids directly from cyclic ethers by dicarbonylation. Different from the general findings that C+1 monocarboxylic acids are produced by carbonylation of cyclic ethers involving alkene intermediates, in this work, by manipulating the reaction system with RhCl 3 and iodine in acetic acid, diiodide-substituted intermediates were selectively formed and subsequently converted to dicarboxylic acids in the presence of H 2 and CO. As high as 84% yield of adipic acid was obtained directly from tetrahydrofuran. This catalytic system is applicable not only to a wide variety of cyclic ethers but also to different primary diols to synthesize C2-elongated α,ω-dicarboxylic acids. This work provides a novel dicarbonylation strategy for the efficient synthesis of adipic acid, glutaric acid and other important α,ω-dicarboxylic acids (such as 1,7-heptanedioic acid and 1,8-octanedioic acid) that are still not easily synthesized by other methods.