请教1,2-双(三甲基硅氧基)乙烷的合成？ < > 我按照文献的方法把 乙二醇 做成1,2-双(三甲基硅氧基)乙烷，乙二醇用DCM溶解，冷却下滴加三乙胺和三 甲基氯硅烷 ，生成较多白色沉淀。反应完毕，过滤白色沉淀，滤液旋干。得到的是固体和液体 混合物 ，选不干。点板感觉极性不对，有文献说是PE/EA=5/1 Rf=0.6，但是我的得到的东西极性较大，在这个极性下基本走不动。所以觉得不对。把这个产物拿到下一步直接用来保护酮，点板极性没有什么变化，怀疑有问题，所以上来请教。</P> < > 下面是两篇文献的制备方法</P> < >A flask equipped with a stir bar and a<BR>pressure-equalized addition funnel was flame-dried under vacuum<BR>and cooled under argon. The flask was charged with diol (1 equiv)<BR>and CH,Cl, (5.0 mL/mmol diol) and cooled to 5 "C in an ice-water<BR>bath. Following the addition of triethylamine (3 equiv) and<BR>chlorotrimethylsilane (2.5 equiv) dropwise via the addition funnel,<BR>a cloudy precipitate formed. The resulting mixture was stirred<BR>and gradually warmed to room temperature. Progress of the<BR>reaction was monitored by TLC. The pink reaction mixture was<BR>filtered and the precipitate washed with anhydrous diethyl ether<BR>several times until no more precipitate formed in the flask. After<BR>concentration, the crude product was purified by column chromatography<BR>on silica gel 60 eluted with 20% EtOAc/hexanes.</P> < >To a solution of 1,2-ethanediole (1.80 g, 1.7 ml, 30.0 mmol, 1.0 eq) in CH2Cl2<BR>(5 ml/mmol of the diole) was added triethylamine (9.11 g, 8.9 ml, 90.0 mmol, 3.0 eq) and<BR>trimethylsilylchloride (8.15 g, 9.5 ml, 75.0 mmol, 2.5 eq). The reaction mixture was stirred for 30<BR>min at rt. The precipitate was then removed by filtration and washed with diethylether. The<BR>solvents were removed under reduced pressure to afford the protected diol 52 (5.01 g, 24.3 mmol,<BR>81 %) which was used without further purification.</P> < > 想请教一下，哪位同学做过，直接指点一下，我这里打核磁比较慢。</P> < > 多谢</P>查看更多0个回答 . 3人已关注
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