反应详情

To a solution of the product from Step B (3.79 g, 12.4 mmol) in anhydrous THF (100 mL) at 0° C. was added N-bromosuccinimide (2.20 g, 12.4 mmol) in 3 portions over 10 min. After 20 min the mixture was poured into a saturated aqueous solution of sodium bisulfite (100 mL) and extracted with EtOAc (3×200 mL). The combined extracts were dried (MgSO4) and evaporated to a residue (4.79 g). Chromatography (silica, 10% EtOAc/hexane) gave a solid (3.66 g, 77%): mp 103-105° C.

1. extractionextracted with EtOAc (3×200 mL)
2. dry with materialThe combined extracts were dried (MgSO4)
3. customevaporated to a residue (4.79 g)