Cesium carbonate → (R)-3-(2,3-dihydro-benzo[1,4]dioxin-6-yl)-5-hydroxymethyl-oxazolidin-2-one

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Reaction Conditions

Reaction Steps

A solution of (2,3-dihydro-benzo[1,4]dioxin-6-yl)-carbamic acid benzyl ester (3.0 g, 10.5 mmol, prepared according to method C) in THF (60 mL) was cooled to −78° C. before the dropwise addition of n-BuLi (5.1 mL of a 2.5M solution in hexanes, 1.2 eq.). The mixture was stirred at −78° C. for 1 h and then warmed to −15° C. At this temperature (R)-glycidyl butyrate (1.98 g, 1.2 eq.) was added dropwise. The mixture was stirred at rt overnight. Cs2CO3 (tip of a spatula) was added and the mixture heated at 40° C. until complete conversion. The mixture was diluted with EA and washed with sat. NH4Cl solution and water. The org. layer was dried over MgSO4 and concentrated. Chromatography on SiO2 (Hex/EA 2:1, 1:1) gave the desired intermediate as a beige solid (1.09 g, 41% yield).

Provenance & Evidence