Electrogenerated base induced N-acylation of chiral oxazolidin-ones

The study of the reactivity of oxazolidin-2-ones 6-11 versus acylating agents (anhydrides 12-15 or acyl chlorides 16 and 17) in solutions containing an electro- generated base (1a-5a) has allowed us to establish a new methodology for the acylation of Evans’ chiral auxiliaries under mild conditions and to avoid any possible epimer- ization. The acid-base reaction is easily performed at room temperature, and a severe control of anhydricity of the medium is not required (bottle dry acetonitrile was used as solvent). N-Acyloxazolidin-2-ones have been isolated in high to excellent yields employing 2-pyrroli- done anion 1a as the electrogenerated base. This EGB (easily obtained by electrolysis, under galvanostatic control, of solutions containing probase 2-pyrrolidone) is stable at room temperature and can be stored for a long time without loss of activity. This methodology represents a further example of the successful use of electrogener- ated bases in organic synthesis.