反应详情

A solution of the product from Example 5A (1.9 g, 4.0 mmol) in THF (30 mL) was treated with 8-phenylmenthol chloroformate prepared from (−)-8-phenylmenthol as described in (Yamamoto, Y., J. Amer. Chem. Soc. (1992), 114, 121-125) (1.45 g, 4.92 mmol) in THF (10 mL), stirred for 3 days at ambient temperature and partitioned between aqueous sodium bicarbonate and methylene chloride. The organic layer as separated, dried with sodium sulfate, filtered and concentrated to provide a mixture of diasteromeric carbamates. The diastereomeric mixture was subjected to column chromatography over silica gel (20% hexanes/ethyl acetate) to provide the title compound (0.32 g) as the less polar diastereomer and mixed fractions containing both diastereomers (0.9 g).

1. custompartitioned between aqueous sodium bicarbonate and methylene chloride
2. customThe organic layer as separated
3. dry with materialdried with sodium sulfate
4. filtrationfiltered
5. concentrationconcentrated
6. customto provide