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Reductions with samarium(II) iodide involve the conversion of various classes of organic compounds into reduced products through the action of samarium(II) iodide, a mild one-electron reducing agent. ==Introduction== In 1979, Kagan observed the reduction of a variety of organic functional groups by samarium iodide under mild reaction conditions. Since that time, samarium iodide has been employed in a variety of contexts in organic synthesis for both functional group manipulation and carbon-carbon bond formation. Samarium iodide is a one-electron reductant, and typically effects reduction through a series of electron transfer and proton transfer (from protic solvent) steps. Reducible functional groups include: *α-Functionalized carbonyl compounds *Ketones and aldehydes *Carboxylic acids (under strongly acidic or basic conditions) *Organic halides *Nitro compounds Some examples of functionality reduced by SmI2 are provided below. ''(1)'' The reactivity of SmI2 is significantly affected by the choice of solvent. The use of hexamethylphosphoramide (HMPA) as a co-solvent in samarium iodide reductions allows the reaction to be carried out under much milder conditions than in its absence. It has recently been investigated and determined that tripyrrolidinophosphoric acid triamide (TPPA) can be used in lieu of HMPA as an activator for SmI2 reductions, producing faster reactions and similar yields while avoiding the use of a known carcinogen. In general, polar solvents increase the strength of samarium iodide as a reducing agent. Samarium iodide is easily prepared in nearly quantitative yields from samarium metal and either diiodomethane or 1,2-diiodoethane. When prepared in this way, it is most often used without isolation as a solution in tetrahydrofuran. ''(2)'' 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Reductions with samarium(II) iodide」の詳細全文を読む スポンサード リンク
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