反应详情

温度

0 °C

At -10° C., a solution of 0.65M KHMDS (potassium hexamethyldisilazide) in toluene (21 mL, 13.65 mmol) was added dropwise to a suspension of the phosphonium salt of Step 4 (8.457 g, 13.53 mmol) in THF (70 mL) and the mixture was stirred at 0° C. for 30 min. At -78° C., a solution of 1H-3-hydroxy-3,4-dihydrobenzo(c)pyran (1.141 g, 7.60 mmol) in THF (14 mL) was added slowly. The mixture was allowed to warm to r.t. and was stirred for a further 3 hours. Aqueous NH4OAc 25% was added and the products were extracted with EtOAc, dried over Na2SO4 and purified by flash chromatography on silica using EtOAc:toluene 10:90 and 15:85. The title compound (2.84 g, 90% yield) was obtained as a cis:trans mixture and was used as such for the next step.

1. temperatureto warm to r.t.
2. stirringwas stirred for a further 3 hours
3. extractionthe products were extracted with EtOAc
4. dry with materialdried over Na2SO4
5. custompurified by flash chromatography on silica