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首页> 外文期刊>Chemistry: A European journal >Exploring SmBr2-, SmI2-, and YbI2-mediated reactions assisted by microwave irradiation
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Exploring SmBr2-, SmI2-, and YbI2-mediated reactions assisted by microwave irradiation

机译：探索微波辐射辅助下的SmBr2-，SmI2-和YbI2介导的反应

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摘要

The use of microwave heating in lanthanide(II) halide (LnX(2) = SmBr2, SmI2, and YbI2) mediated reduction and coupling reactions has been investigated for a variety of functional groups including alpha,beta-unsaturated esters, aldehydes, ketones, imines, and alkyl halides. Good to quantitative transformations were obtained within a few minutes without the addition of any co-solvents. such as hexamethyl phosphoramide (HMPA). The redox potential of YbI2, in tetrahydrofuran (THF) has been determined as -1.02 +/- 0.05 V (versus Ag/AgNO3) by cyclic voltammetry. A large selectivity difference in various reactions was observed depending on the redox potential of the LnX(2) reagent. The more powerful reductant, SmBr2, afforded mainly pinacol-coupling products of ketones whereas the weaker reductant YbI2 afforded mainly reduction products. The results indicate that the reducing power of LnX(2) has a large impact on not only the pinacol coupling/reduction product ratio of ketones but also on other substrates in which there are competing coupling and reduction reactions. The use of in situ generated LnX(2) has also been explored and proven useful in many of these reactions.
机译：微波加热在镧系元素（II）卤化物（LnX（2）= SmBr2，SmI2和YbI2）介导的还原和偶联反应中的用途已被研究，涉及各种官能团，包括α，β-不饱和酯，醛，酮，亚胺和卤代烷。在几分钟内无需添加任何助溶剂即可实现良好的定量转化。例如六甲基磷酰胺（HMPA）。通过循环伏安法已确定YbI2在四氢呋喃（THF）中的氧化还原电势为-1.02 +/- 0.05 V（相对于Ag / AgNO3）。根据LnX（2）试剂的氧化还原电位，在各种反应中观察到较大的选择性差异。较强效的还原剂SmBr2主要提供酮的频哪醇偶联产物，而较弱的还原剂YbI2主要提供还原产物。结果表明，LnX（2）的还原能力不仅对酮的频哪醇偶联/还原产物比率有很大影响，对其他存在竞争性偶联和还原反应的底物也有很大的影响。还探讨了原位生成的LnX（2）的使用，并证明在许多这些反应中有用。

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