First use of a divalent lanthanide for visible-light-promoted photoredox catalysis

Abstract

Divalent europium is used catalytically in visible-light-promoted photoredox bond-forming reactions.

A chiral nickel DBFOX complex as a bifunctional catalyst for visible-light-promoted asymmetric photoredox reactions

“…In combination with its highly organized chiral environment and redox-active metal center, we envisioned that such a complex might be a potential candidate for asymmetric/photoredox bifunctional catalysis. 19 With these considerations in mind, we commenced our study with α,β-unsaturated crotonyl oxazolidinone 1a and tertiary α-silylamine 2a as the model substrates. We here chose tertiary α-silylalkylamines as the target substrate because they have low oxidation potentials (for example, E ox ( 2a˙ + / 2a ) = +0.60 in CH 3 CN, Fig.…”

Europium‐Catalyzed Aerobic Oxidation of Alcohols to Aldehydes/Ketones and Photoluminescence Tracking

“…[14] However, some metals, such europium, samarium, and ytterbium, can exist in both 2 + and 3 + oxidation states. Dimerization of a-methyl styrene, [18] allylation of aldehydes, [19] and reductive coupling of benzyl chloride [20] were performed with europium salts and the their redox cycles under photochemical conditions. [16] Both Eu(II) and Eu(III) salts are commercially available from multiple chemical suppliers.…”

Gadolinium Photocatalysis: Dearomative [2+2] Cycloaddition/Ring‐Expansion Sequence with Indoles

“…[27] Notably,t he individual Gd(OTf) 3 (1 mol %) or 1a (5 mol %) showed dramatically inferior catalytic activity in this isomerization reaction (entries 3and 4). Finally,this transformation was suppressed remarkably in the presence of excited state quenchers,s uch as triplet molecular oxygen, Ni(acac) 2 and Cu(acac) 2 (see Supporting Information). Overall, all these observations strongly support the visible-violet-light-enabled formation of the long-lived excited state intermediate A, which lays the foundation of the entire transformation.…”

“…[1] Theabundant lanthanide metals with advantages of low cost, high stability,f lexible coordination ability,a nd unique electrochemical and photophysical properties,a re relatively underexplored. [2] Cerium photocatalysis has been demonstrated in diverse organic transformations such as CÀCb ond cleavage,C ÀC/X bond formation and selective functionalization of inactive C(sp 3 ) À Hbond by the excellent contributions from the groups of Zuo [3] and Schelter. [4] In contrast, utilization of other photoactive lanthanide metals is very limited.…”