反应详情

n-Butyl lithium (0.85 mL, 1.36 mmol, 1.6 M in hexanes) was added dropwise over 10 min to a solution of 3,4,5-trimethoxybenzylphosphonium bromide (0.58 g, 1.12 mmol) in THF (7 mL) at −10° C. The reaction mixture was stirred at this temperature for 15 min then cooled to −70 C and a solution of 35 (0.47 g, 1.14 mmol) in THF (3 mL) was added and the reaction mixture was allowed to warm to room temperature with stirring overnight. The reaction mixture was cooled to 0° C. and water was added. The reaction mixture was extracted with TBME (3×) and the organic phase was washed successively with water and brine, dried (Na2SO4) and concentrated in vacuo to give crude product (0.67 g). Purification by column chromatography (SiO2 2:98 EtOAc:cyclohexane+1% Et3N) gave 36 (0.21 g, 34%) as an 89:11 mixture of Z:E isomers.

1. temperaturethen cooled to −70 C
2. stirringwith stirring overnight
3. temperatureThe reaction mixture was cooled to 0° C.
4. extractionThe reaction mixture was extracted with TBME (3×)
5. washthe organic phase was washed successively with water and brine
6. dry with materialdried (Na2SO4)
7. concentrationconcentrated in vacuo
8. customto give crude product (0.67 g)
9. customPurification by column chromatography (SiO2 2:98 EtOAc:cyclohexane+1% Et3N)