Generation and reactivity of C(1)-ammonium enolates using isothiourea catalysis

Abstract

C(1)-ammonium enolates are powerful, catalytically generated synthetic intermediates applied in the enantioselective α-functionalization of carboxylic acid derivatives. This review describes the recent developments in the generation and application of C(1)-ammonium enolates from various precursors (carboxylic acids, anhydrides, acyl imidazoles, aryl esters, α-diazoketones, alkyl halides) using isothiourea Lewis base organocatalysts. Their synthetic utility in intra- and intermolecular enantioselective C-C and C-X bond forming processes on reaction with various electrophiles will be showcased utilizing two distinct catalyst turnover approaches.