Synthesis of secondary and tertiary amides without coupling agents from amines and potassium acyltrifluoroborates (KATs).

ABSTRACT: Although highly effective for most amide syntheses, the activation of carboxylic acids requires the use of problematic coupling reagents and is often poorly suited for challenging cases such as N-methyl amino acids. As an alternative to both secondary and tertiary amides, we report their convenient synthesis by the rapid oxidation of trifluoroborate iminiums (TIMs). TIMs are easily prepared by acid-promoted condensation of potassium acyltrifluoroborates (KATs) and amines and are cleanly and rapidly oxidized to amides with hydrogen peroxide. The overall transformation can be conducted either as a one-pot procedure or via isolation of the TIM. The unique nature of the neutral, zwitterionic TIMs makes possible the preparation of tertiary amides via an iminium species that

SUBMITTER: Schuhmacher A 

PROVIDER: S-EPMC8152719 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature