ON THE MAXIMUM ROTATION AND THE SOLVOBROMINATION AND -MERCURATION OF ENANTHIOENRICHED 1,3-DIMETHYLALLENE
ON THE MAXIMUM ROTATION AND THE SOLVOBROMINATION AND -MERCURATION OF ENANTHIOENRICHED 1,3-DIMETHYLALLENE
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富对映体1,3-二甲基联烯的最大旋转度及溶剂溴化和汞化
DOI：
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发表时间：
1991
期刊：
影响因子：
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通讯作者：
K. Sugi
中科院分区：
文献类型：
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作者：
D. Pasto;K. Sugi
对映体纯的1，3-二甲基丙二烯（13 DMA）的甲氧基溴化和汞化的对映体富集的13 DMA的基础上的最大旋转的先前的分配被证明是严重错误的。用手性NMR shit试剂直接测定了13 DMA的[α] 589值为81.0±0.2 o（25 o C乙醚溶液）。甲氧基溴化和汞化反应，这是以前提出的完全立体定向，显示发生与大量损失ee，这表明中间鎓离子中间体进行竞争性开环的非手性取代的烯丙基阳离子，从而导致损失ee
The prior assignments of the maximum rotation of enantiomerically pure 1,3-dimethylallene (13 DMA) based on the methoxybromination and -mercuration of enantioenriched 13 DMA are shown to be drastically in error. A value of [α] 589 of 81.0±0.2 o (25 o C in diethyl ether) has been determined directly on enantioenriched samples of 13 DMA by the use of a chiral NMR shit reagent. The methoxybromination and -mercuration reactions, which were previously suggested to be completely stereospecific, are shown to occur with substantial losses in ee, suggesting that the intermediate onium ion intermediates undergo competitive ring opening to achiral substituted allyl cations thus resulting in loss of ee