Divalent lanthanide derivatives in organic synthesis. 1. Mild preparation of samarium iodide and ytterbium iodide and their use as reducing or coupling agents

Abstract

The facile synthesis of Sml2 and Ybl2 from corresponding metals in THF is described. The reactivity of these potentially powerful reducing agents toward a variety of functional groups is tested. Epoxides and sulfoxides are deoxygenated. Aldehydes are selectively reduced in presence of a ketone. Alkyl halides or tosylates are converted into alkanes. Only coupling products are obtained from benzylic or allylic halides. In the presence of a SmI2-THF solution, tertiary alcohols are easily obtained from reactions between ketones and alkyl halides. In a similar manner, Sml2 promotes straightforward alkylation of ketones by alkyl sulfonates. Selective addition of polyfunctional halides or tosylates to ketones may be performed. In these reactions, catalytic amounts of FeCb enhance the reactivity.

Organic-Fluorous Phase Switches: A Fluorous Amine Scavenger for Purification in Solution Phase Parallel Synthesis

“…Isopropenyl acetate and acetone cyanohydrin were purchased from a commercial origin and distilled prior to use. Cp*2Sm(thf)2, 13 Cp*2Yb(thf)2, 13 Sm(O i Pr)3, 14 Sm(OTf)3, 15 SmI2, 16 and SmI3 17 were prepared according to literature procedures.…”

Recent developments in cyclization reactions of α-aminoalkyl radicals

“…52 However, imines 76a are much less reactive towards SmI 2 than the corresponding aldehydes because of the lower electron deficiency of the former. Thus, SmI 2 -promoted pinacol formation from aliphatic aldehydes is an easy process taking place already at 25 °C, 53 whereas the corresponding reductive dimerization of aliphatic aldimines requires elevated temperatures. …”

Fine Synthetic Nucleoside Chemistry Based on Nucleoside Natural Products Synthesis

“…Over the past decade, it has been shown that samarium diiodide (SmI 2 ) can be used as an efficient electron-transfer reagent in a variety of transformations in organic chemistry due to its functional-and stereoselectivity. [44][45][46][47][48][49][50][51][52] The reaction conditions using SmI 2 are very mild, and it is suitable for the reactions using unstable 3Ј-ketonucleosides as a substrate. These prompted us to explore a new method for producing 3Ј-b-branched ribonucleoside analogs (Fig.…”