Abstract
A 4, 5-unsubstituted 2-oxazolone moiety has proved of much synthetic potential as an excellent leaving group in carboxy-activating processes, in contrast with the 2-oxazolidinones. These findings led to the development of new versatile reagents, diphenyl 2-oxo-3-oxazolinylphosphonate [DPPOx] and 3-acyl- and 3-alkoxycarbonyl-2-oxazolones as well as their homo- and copolymers reactive enough to serve as highly chemo- and regioselective acylating agents. The DPPOx provides one-step and high-yield routes to 3-acyloxazolides, peptides, β-lactams, thiol esters and esters from a wide variety of carboxylic acids.
Scope and advantages of these “ready-to-use” type reagents' newly introduced are discussed from a preparative point of view.
