Divergent transformations of N-phenyl-N-tosylfluoroacetamides to amides and imides (N-tosylamides)

Abstract

The strained C–N bond of N-phenyl-N-tosylfluoroacetamides is activated via a transition-metal-free nucleophilic addition pathway by employing suitable nucleophilic reagents, such as indoles, indolines, aryl amines and carboxylic acids. Based on this, two efficient and convenient approaches are developed for the synthesis of amides by utilizing divergent fragments of N-phenyl-N-tosylfluoroacetamides in this study. The reaction of nitrogen-containing compounds and carboxylic acids with N-phenyl-N-tosylfluoroacetamides proceeded smoothly in the presence of a base to afford diverse fluoroacetamides and N-tosylamides in satisfactory-to-excellent yields. N-Phenyl-N-tosylfluoroacetamides served as integrated reagents to provide either a fluoroacetyl or amine source, depending on the substrate with which they were reacted. These protocols are amenable to scale up. Various groups, including the synthetically useful functional groups Br, NO₂, OH and CO₂Me, were tolerated well under the current reaction conditions.