Formation of epoxides from pentacoordinated organoarsenic compounds with a β-hydroxyethyl group
作者:Xin-Dong Jiang、Shiro Matsukawa、Yuta Fukuzaki、Yohsuke Yamamoto
DOI:10.1039/c0nj00035c
日期:——
A series of pentacoordinated organoarsenic compounds (arsoranes) bearing a β-hydroxyethyl group (4a, 6a and 6b) was synthesized. The crystal structures were determined by single crystal X-ray analysis. Treatment of these arsoranes with KH almost quantitatively gave the corresponding epoxide. The reaction of 4a having an unsubstituted β-hydroxyethyl group with KH was monitored by 1H and 19F NMR in CD3CN, suggesting that a hexacoordinate arsenic anion was formed as the intermediate. However, a further stereochemical study of the epoxide formation suggested that the reaction proceeded in the SN2 manner and not in the ligand coupling reaction (LCR) of the intermediate hexacoordinate arsenic anion.
合成了一系列带有β-羟乙基(4a、6a 和6b)的五配位有机砷化合物(arsoranes)。通过单晶X射线分析确定晶体结构。用 KH 处理这些砷烷几乎定量地得到相应的环氧化物。具有未取代的β-羟乙基的4a 与KH 的反应通过CD3CN 中的1H 和19F NMR 监测,表明形成了六配位砷阴离子作为中间体。然而,对环氧化物形成的进一步立体化学研究表明,反应以 SN2 方式进行,而不是以中间体六配位砷阴离子的配体偶联反应 (LCR) 进行。