1.09 Samarium and Ytterbium Reagents

Two‐Step Sequence Multicomponent Synthesis/Reductive Rearrangement of 2‐Acyl‐2,3‐dihydrofurans for Modular Assembly of Annulated 4H‐Pyrans

“…Though SmI 2 is a good synthetic tool (a mild, neutral and ether‐soluble one‐electron reductant), its sensitivity to air makes it rather difficult to handle. Samarium is a relatively reactive metal existing in the oxidation states +2 and +3, which can be considered as a strong two‐ and three‐electron reducing agent (ϕ°(Sm 0 /Sm 3+ )=−2.41 V) [24] . Due to its high activity, a twice single‐electron reduction of the carbonyl group of dihydrofuran to the zwitterion I can initially occur.…”

“…In addition, lanthanides are not characterized by the formation of carbenoid complexes, [27] which also justifies the formation of carbene III as a result of elimination of [(trimethylsilyl)oxy]samarium (II) chloride from intermediate II . In turn, [(trimethylsilyl)oxy]samarium (II) chloride itself is a strong one‐electron reductant (ϕ°(Sm 2+ /Sm 3+ )=−1.55 V) [24] and can reduce the carbonyl group of starting dihydrofuran via double single‐electron transfer acts with the formation of intermediate IV (Scheme 4, route 2). The latter is converted into carbene III due to elimination of two molecules of samarium (III) oxide chloride and hexamethyldisiloxane (HMDSO).…”

“…Samarium is a relatively reactive metal existing in the oxidation states + 2 and + 3, which can be considered as a strong two-and threeelectron reducing agent (ϕ°(Sm 0 /Sm 3 + ) = À 2.41 V). [24] Due to its high activity, a twice single-electron reduction of the carbonyl group of dihydrofuran to the zwitterion I can initially occur. Its subsequent silylation on exocyclic oxygen atom leads to an intermediate II (Scheme 4, route 1).…”

Structural Diversity and Multielectron Reduction Reactivity of Samarium(II) Iodido-β-diketiminate Complexes Dependent on Tetrahydrofuran Content

“…Lanthanide halides and halide complexes are widely used as starting materials for the syntheses of organolanthanide compounds, e.g., in salt metathesis − and reduction , processes. Those of divalent lanthanides, most importantly SmI 2 , are widely utilized as powerful and selective reductants for various organic transformations. − Knowing their exact structures is important for the following chemistry, not only for determining the stoichiometry in their reactions but also for understanding reactivity, magnetic interactions, and other properties, which depend on the local environment of the Ln cation. Multiple studies showed that the molecular structures of lanthanide halide complexes highly depend on the donor solvent used in the synthesis. , Coordination of small donor molecules mainly leads to mononuclear complexes.…”

Rate and Mechanistic Investigation of Eu(OTf)2-Mediated Reduction of Graphene Oxide at Room Temperature

“…In this paper, we have provided alternate ways of preparing rGO under mild conditions using divalent lanthanide complexes. Divalent-lanthanide-based reductants have been widely utilized for various functional group transformations in organic chemsitry. − While most of the divalent-lanthanide-mediated reactions are promoted by Sm(II) salts, studies have shown that Eu(II) salts can also be utilized for selective reduction processes. − Hence, the mild nature of Eu(II) as a reductant is utilized in the present work for reducing the functional groups in GO, keeping the carbon–carbon network intact. Other divalent lanthanides such as Sm(II), Yb(II), Tm(II), and so forth are found to reduce CC, which is a highly undesired process in the reduction of GO. , …”