An inexpensive catalyst, Fe(acac)3, for regio/site-selective acylation of diols and carbohydrates containing a 1,2-cis-diol

Abstract

This work describes the [Fe(acac)₃] (acac = acetylacetonate)-catalyzed, regio/site-selective acylation of 1,2- and 1,3-diols and glycosides containing a cis-vicinal diol. The iron(III) catalysts initially formed cyclic dioxolane-type intermediates with substrates between the iron(III) species and vicinal diols, and the efficient and selective acylation of one hydroxyl group was subsequently achieved by adding acylation reagents in the presence of diisopropylethylamine (DIPEA) under mild conditions. This reaction generally produced high selectivities and highly isolated yields with the same protection pattern as that achieved with dibutyl tinoxide-mediated schemes.