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

• Published in: Tetrahedron 2017-10, Vol.73 (40), p.5883-5891
• Main Authors: Ha, Phuong T.M., Le, Thuan D., Doan, Son H., Nguyen, Tung T., Le, Nhan T.H., Phan, Nam T.S.
• Format: Article
• Language: English
• Subjects: Carboxylic acid; Catalysis; Esterification; Metal-organic frameworks; α-Acyloxy ether
• ISSN: 0040-4020; 1464-5416
• DOI: 10.1016/j.tet.2017.08.040

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. [Display omitted] •MOF-235 was used as catalyst for the direct esterification reaction.•High yields of α-acyloxy ethers were obtained.•The catalyst could be recovered and reused.