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Clarification of the Reduction Behaver of Photoexcited Samarium Species and its Application to the Development of New Synthetic Process

光激发钐物种还原行为的阐明及其在新合成工艺开发中的应用

基本信息

批准号：
10555315
负责人：
OGAWA Akiya
金额：
$ 1.15万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

It has been revealed that the irradiation with visible light enhances the reducing ability of samarium diiodide. While the reduction of organic chlorides with SmIィイD22ィエD2 alone is difficult, irradiation with visible light causes the efficient reduction of organic chlorides to the corresponding hydrocarbons. Upon irradiation with visible light, gem-dichlorocyclopropanes undergo reductive dechlorination with samarium diiodide and benzenethiol to provide the corresponding cyclopropanes in good yields. The reaction may proceed via the hydrogen abstraction from PhSH by cycolopropyl radicals formed in situ by the reduction with SmIィイD22ィエD2. A novel photoinduced reduction of group 16 heteroatom compounds such as organic selenides, tosylates, and tellurides has also been developed. In particular, organic selenides, which can not be reduced with SmIィイD22ィエD2 in the dark (or even in the presence of HMPA), undergo reductive cleavage efficiently by using the SmIィイD22ィエD2-hv system. Moreover, the photoinitiated reaction of alkyl chlorides (R-Cl) with SmIィイD22ィエD2 in the presence of carbon monoxide (50 atm) is examined. The reaction provides the corresponding asymmetrical ketones (RC(=O)CHィイD22ィエD2R) as a carbonylated product. A mechanistic proposal includes the dimerization of acylsamarium species formed in situ by the reductive carbonylation of alkyl chlorides with CO and SmIィイD22ィエD2. Irradiation with near-UV light dramatically also enhances the reducing ability of ytterbium diiodide (YbIィイD22ィエD2). Organic bromides, iodies, tosylates, and tellurides are reduced efficiently by a YbIィイD22ィエD2-hv system, while these can not be reduced with YbIィイD22ィエD2 in the dark.

结果表明，可见光照射增强了二碘化钐的还原能力。而有机氯化物的降低重度ィイD22摊位ィエD2仅是困难的,与可见光辐照导致有机氯化物的有效减少相应的碳氢化合物。在可见光照射下，宝石二氯环丙烷用二碘化钐和苯硫醇还原脱氯，得到相应的高收率环丙烷。该反应可以通过SmI γ γ γ - D22 γ γ - D2还原原位形成的环丙基自由基从PhSH中抽氢进行。一种新的光诱导还原16族杂原子化合物，如有机硒化物、甲酰酸盐和碲化物。特别是，在黑暗中（甚至在HMPA存在的情况下）SmI γ γ γ无法还原的有机硒化物，在SmI γ γ γ γ γ γ -hv体系下可以有效地进行还原解理。此外，还研究了在一氧化碳（50 atm）存在下，烷基氯化物（R-Cl）与SmI γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ的光引发反应。该反应生成了相应的不对称酮（RC(=O)CH γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ）羰基化产物。一种机制建议包括酰基钐的二聚化是由烷基氯化物与CO和SmI的还原羰基化形成的。近紫外光照射也显著增强了二碘化镱（YbI D22 D2）的还原能力。有机溴化物、碘化物、甲酰酸盐和碲化物在YbI γ γ - γ -hv体系中可以有效地还原，而在黑暗中，YbI γ γ - γ - D22 γ - γ - D2不能还原。