The chemoselectivesynthesis of the 1,7-lactones of N-acetylneuraminic acid, N-glycolylneuraminic acid, and 3-deoxy-d-glycero-d-galacto-nononic acid is accomplished in two steps: a simple treatment of the corresponding free sialicacid with benzyloxycarbonyl chloride and a successive hydrogenolysis of the formed 2-benzyloxycarbonyl 1,7-lactone. The instability of the 1,7-lactones to protic solvents
General and Chemoselective N-Transacylation of Secondary Amides by Means of Perfluorinated Anhydrides
作者:Paola Rota、Pietro Allevi、Raffaele Colombo、Maria L. Costa、Mario Anastasia
DOI:10.1002/anie.200906055
日期:2010.3.1
A direct route: The N‐transacylation of secondaryamides to their perfluorinated analogues with the possibility of subsequent conversion into a normal amide is reported (see scheme). This reaction occurs in the presence of a variety of functional groups that are labile to the hydrolysis conditions required by classical N‐transacylation.