反应详情

温度

-70 °C

3.4 ml of a 1.95M butyllithium in cyclohexane solution were slowly added at -70° C. to a solution of 1.24 g of p-tolyl isopropyl sulfone in 13 ml of tetrahydrofuran and the mixture was stirred at -70° C. for 15 minutes. Then, a solution of 1 g of methyl 4,4-dimethoxy-2-butenoate in 20 ml of tetrahydrofuran was slowly added to the mixture which was stirred at -70° C. for one hour and poured into a aqueous monosodium phosphate solution. The mixture was extracted with methylene chloride and the organic phase was dried and evaporated to dryness under reduced pressure. The residue was chromatographed over silica gel and was eluted with a 1--1 ether-petroleum ether (b.p.=40°-70° C.) mixture to obtain 1.1 g of methyl 4-p-toluenesulfonyl-4-methyl-3-dimethoxymethyl-pentanoate melting at 110° C.

1. stirringwas stirred at -70° C. for one hour
2. extractionThe mixture was extracted with methylene chloride
3. customthe organic phase was dried
4. customevaporated to dryness under reduced pressure
5. customThe residue was chromatographed over silica gel
6. washwas eluted with a 1--1 ether-petroleum ether (b.p.=40°-70° C.) mixture