Zirconium oxychloride hydrate: an efficient and reusable catalyst for retro-Claisen condensation of alcohols with 1,3-diketones

Abstract

Esters are one of the most versatile and fundamental class of compounds with tremendous industrial demand. They are generally synthesized via the condensation of alcohols with acids. Herein, we report zirconium oxychloride hydrate as an efficient and reusable catalyst for the synthesis of esters from alcohols and 1,3-diketones. The reaction tolerates a wide range of alcohols, including primary and secondary alcohols, electron-rich and electron-deficient alcohols, and various natural alcohols. This methodology provides an alternative way to synthesize several industrially relevant acetates, such as n-butyl acetate, isobutyl acetate, 2-ethylhexyl acetate and isopropyl acetate, in high yields. The catalyst can be recovered from the reaction mixture and reused for up to 5 cycles without any significant change in catalytic activity. To the best of our knowledge, this is the first example of a reusable catalyst used in the synthesis of esters via retro-Claisen type condensation of alcohols and 1,3-diketones.