2.2 Samarium-Mediated Reductions

Abstract

AbstractSamarium(II)-based reductants have been shown to be a group of very powerful reagents whose reactivity can be tuned significantly by the use of additives. The use of additives has been shown to greatly impact the rate, diastereoselectivity, chemoselectivity, and mechanism by which these reactions proceed, making these systems extremely useful and versatile. These reagents have been shown to promote several reactions including reductions of a range of functional groups and a variety of carbon–carbon bond forming reactions. More recently, initial work has demonstrated catalytic reactions of samarium(II)-based reductants. This chapter focuses on the chemistry of samarium diiodide (SmI2) and a few other samarium(II)-based reductants, with examples of the reactions they promote, both with and without the use of additives. Additionally, recent work on the mechanistic understanding of catalytic reactions using terminal reductants and a novel example of an approach employing radical relay that negates the use of a terminal reductant are presented.