Practical synthesis of 2,5-disubstituted 1,3-dioxolane-4-ones and highly diastereoselective cis-2,5-disubstituted 1,3-dioxolane-4-ones from α-hydroxy acids catalyzed by N-triflylphosphoramide
摘要:
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.
A new highly diastereoselective synthesis of 2,5-disubstituted-1,3-dioxolan-4-ones from α-hydroxyacids
作者:N. Chapel、A. Greiner、J-Y. Ortholand
DOI:10.1016/0040-4039(91)80352-7
日期:1991.3
Reaction of α-hydroxyacids with acetals under weak acid catalysis gave the corresponding dioxolanones with a better diastereomeric ratio than the usual strong acid catalyzed synthesisfrom aldehydes.