ACTIVATION OF CARBOXYL GROUPS BY DIPHENYL 2-OXO-3-OXAZOLINYLPHOSPHONATE. FACILE PREPARATION OF VERSATILE REAGENTS, 3-ACYL-2-OXAZOLONES

Article abstract of DOI:10.1016/S0040-4020(01)91572-8

Synthetic utility of the 2-oxazolone moiety as an excellent new leaving group is described.Based on such a function of the heterocycles, diphenyl 2-oxo-3-oxazolinylphosphonate has been newly introduced as a carboxyl-activating reagent which permits a facile direct preparation of 3-acyl-2-oxazolones and amides including peptides from a wide variety of carboxylic acids.The 3-acyl-2-oxazolides also serve as versatile reactive agents for highly chemoselective acyl-transfer to the nucleophilic species such as amines, alcohols and thiols, providing convenient and high-yield routes to amides, esters and thiol esters under mild conditions.They are also useful intermediates for ketones and alcohols.