Synthesis of α-acyloxy ethers via direct esterification of carboxylic acids with ethers under metal-organic framework catalysis

Abstract

An iron-organic framework MOF-235 was synthesized, and utilized as an effective heterogeneous catalyst for the synthesis of α-acyloxy ethers via direct esterification of carboxylic acids with C(sp3)H bonds. The iron-based framework showed higher catalytic productivity than numerous homogeneous catalysts and than various MOFs in the direct esterification reaction. The generation of α-acyloxy ethers was considerably adjusted by the oxidant, and di-tert-butyl peroxide emerged as the best candidate. Heterogeneous catalysis was verified, and α-acyloxy ethers were not produced via the contribution of leached iron species. The framework catalyst was reutilized many times for the transformation without a remarkable decline in catalytic activity. According to our best knowledge, this is the first heterogeneous catalytic approach towards the synthesis of α-acyloxy ethers via direct esterification of carboxylic acids with C(sp3)H bonds.