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Sodium metal (13.7 g, 0.59 mol) was dissolved in 500 ml of absolute ethanol, and the resulting ethoxide solution was cooled to 0° C. Crude 5-bromo-2,2,6-trimethyl-4H-1,3-dioxin-4-one (115.5 g, 0.5 mole at 95% purity) was then added, dropwise, to the chilled ethoxide solution over 30 minutes and the dark orange reaction mixture was stirred an additional 30 minutes at 0° C. The reaction was poured into 500 ml of ether and 550 ml of 1N HCl, and the organic layer was washed repeatedly with water (4×250 ml) and then dried over Na2SO4. Removal of solvent in vacuo (30° C., 2 Torr), followed by distillation on a 2-inch wiped-film molecular still (120° C. jacket, 0.2 Torr) afforded 68.7 g (71%) of a pale yellow oil (98% pure by gc).

1. washthe organic layer was washed repeatedly with water (4×250 ml)
2. dry with materialdried over Na2SO4
3. customRemoval of solvent in vacuo (30° C., 2 Torr)
4. distillationfollowed by distillation on a 2-inch
5. customstill (120° C. jacket, 0.2 Torr)