Obtaining protoanemonin through selective oxidation of Dfructose and 5-(hydroxymethyl) furfural in a self-catalysed reaction

Abstract

Although different ways of converting 5- (hydroxymethyl)furfural (1) to various substrates with high value have been sought, few transformations have obtained building blocks that can be very useful in the area of fine chemistry. Herein, we report the synthesis of protoanemonin (5-methylenefuran-2(5H)- one) from D-fructose via compound (1), a versatile γalkylidenebutenolide, using an efficient self-catalysed process with formic acid, with high reaction performance and selectivity (up to 94% yield and 98% conversion from (1), while 28% yield from Dfructose). This efficient and simple operational process involved a two-phase aqueous-organic system between chlorinated solvents (CHxCly) and hydrogen peroxide as the initial oxidizing agent. The reaction presents a key cleavage in the 5-hydroxymethyl moiety of (1), due to the Baeyer-Villiger oxidation (BVO) process that generates formic acid in situ. Ultimately, DFF and HMF were successfully obtained in 80% and 98% yield, respectively, starting from D-fructose and using Preyssler heteropolyacids as Brønsted acid catalysts under an atmosphere of oxygen in the absence of hydrogen peroxide.