Oxonium, trimethyl-, tetrafluoroborate(1-) (1:1) → (RS)-3-(3-Bromo-phenyl)-5-methoxy-3-methyl-3,6-dihydro-2H[1,4]oxazine

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Reaction Steps

In a vacuum dried flask under an argon atmosphere, a solution of (RS)-5-(3-bromo-phenyl)-5-methyl-morpholin-3-one (3.0 g, 11.1 mmol) in dichloromethane (145 ml) was treated with trimethyloxonium tetrafluoroborate (2.594 g, 17 mmol). The reaction mixture was stirred at room temperature for 17 hours. For the workup, the incomplete reaction was extracted with a saturated solution of sodium hydrogen-carbonate (70 ml). The organic layer was dried over sodium sulfate and evaporated. There were obtained 3.12 g of the title compound as light yellow oil containing about 17% of the starting lactam. Mass (calculated) C12H14BrNO2 [284.16]; (found) [M+H]+=284, [M+2-H]+=286.

Provenance & Evidence