Practical synthesis of 2,5-disubstituted 1,3-dioxolane-4-ones and highly diastereoselective cis-2,5-disubstituted 1,3-dioxolane-4-ones from alpha-hydroxy acids catalyzed by N-triflylphosphoramide

Abstract

N-triflylphosphoramide (NTPA) was found to be an efficient Bronsted acid catalyst for the practical synthesis of 2,5-disubstituted 1,3-dioxolane-4-ones. Racemic and optically pure mandelic acid and lactic acid could be protected using several aldehydes in high selectivity and moderate yield in the presence of NTPA without azeotropic distillation or use of a dehydrating reagent. (C) 2015 Elsevier Ltd. All rights reserved.