longed reaction for a week in the presence of Cs2C03 or Na2C03 raised the yields to 70-90%. Since isolation of the intermediate ammonium carbamates is not necessary and the oxazolidinones and oxazinanones are the only isolable products, the reactions constitute one-pot procedures. Moreover, purification of the products is very easy. The structures of the products were deduced from their elemental analyses and from the IR or NMR spectra. As listed in Table , all the oxazolidinones exhibit their C=O absorption band near 1730 cm-', which is in agreement with a five-membered carbamate. The characteristic, strong C=O absorptions for the oxazinanones are observed around 1685 cm-'. The scope and limitations of this reaction are now being studied.
Experimental Procedure
A solution of allylamine (4.0 mmol) in MeOH (4 mL) in an ice-cooled bath was saturated with C 0 2 . l2 (2 mmol) was added to the solution, and C02 was admitted for a n additional 5 min. The reaction mixture was then stirred for 20 h under C 0 2 at room temperature. The excess iodine was removed by addition of aqueous Na2S20,, and the MeOH was removed in vacuo at 40ยฐC. Extraction with ethyl acetate, drying over Na,SO,, and removal of the solvent gave 5-iodomethyl-2-oxazolidinone, which was purified by recrystallization from ethyl acetate. The reaction of the homoallylamines was carried out similarly. Reaction for one week in the presence of Cs2COs (2 mmol) raised the yields to the values shown in parentheses in Table .