反应详情

3.4 ml of a 1.95 M of butyllithium per liter of hexane were added at -70° C. to a mixture of 1.24 g of p-tolyl isopropyl sulfone in 13 ml of tetrahydrofuran and after stirring the mixture for 15 minutes, a solution of 1 g of methyl (E) 4,4-dimethoxy-2-butenoate in 20 ml of tetrahydrofuran was slowly added thereto. The mixture was stirred at -20° C. for one hour and was then poured into an 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 an ether-petroleum ether (b.p. =40° to 70° C.) mixture to obain 1.1 g of methyl 4-p-tolylsulfonyl-4-methyl-3-dimethoxymethyl-pentanoate melting at 110° C.

1. stirringThe mixture was stirred at -20° 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 an ether-petroleum ether (b.p. =40° to 70° C.) mixture