Reactions of Carboxylic Acids with "Phosphonium Anhydrides"

Article abstract of DOI:10.1021/jo00266a028

General considerations are outlined for a reagent to extract oxygen from organic molecules by an equivalent of dehydration.Reagents, (R3P⁺)2O, 2OTf^-, were created for the purpose and subjected to a preliminary study.They were found to convert carboxylic acids readily and rapidly to anhydrides, esters, amides, amidines, benzimidazoles, and cyclic aryl ketones in good yields.