4-[(3aR,4R,5S,7S,7aS)-5-Benzenesulfonyl-2,2,3a,7-tetramethyl-5-(2-trimethylsilanyl-ethylsulfanyl)-hexahydro-benzo[1,3]dioxol-4-yl]-3-oxo-butyric acid methyl ester 生成 methyl 4-[(3aR,4R,7S,7aS)-2,2,3a,7-tetramethyl-5-(2-trimethylsilylethylsulfanyl)-5,6,7,7a-tetrahydro-4H-1,3-benzodioxol-4-yl]-3-oxobutanoate