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The regio- and stereoselective copper-mediated hydroxylation of a non-activated aliphatic C−H bond in steroids by dioxygen, initially reported by Schönecker et al. ( Angew. Chem. Int. Ed. 2003, 42, 3240-3244), has recently evolved into a valuable synthetic tool. In the present work, a detailed mechanistic density functional theory (DFT) study addressing the origin of the remarkable selectivity of Schönecker's reaction is reported. The applied BLYP-D3/def2-TZVP(SDD) level of DFT is benchmarked against experimental and coupled-cluster reference data. The resulting mechanistic scenario involves formation of a bis-μ-oxo dicopper complex as key intermediate. In this complex three C−H bonds of the pendant steroid ligand are predisposed towards intramolecular activation by the bis-μ-oxo dicopper core. The lowest activation barrier (12.0 kcal mol−1) is computed for β-hydroxylation at the C12 position, in agreement with the experimental observations. Natural bond orbital (NBO) analysis reveals stabilizing orbital interactions that favor the β-hydroxylation pathway over competing reaction channels. [ABSTRACT FROM AUTHOR]

Background: The envelope protein (ENV) of the human endogenous retrovirus type W is implicated in inflammatory reactions in multiple sclerosis (MS) but also interferes with oligodendroglial maturation. A neutralizing antibody GNbAC1 has been developed and successfully been tested in clinical trials. Objectives and methods: We stimulated primary oligodendroglial cells with ENV upon preincubation with GNbAC1 and assessed for nitrosative stress and myelin expression. Results: Neutralization of ENV by GNbAC1 reduces its ability to induce stress reactions resulting in a rescue of myelin expression. Conclusions: Beyond immune cell modulation, this monoclonal antibody may therefore help to overcome the oligodendroglial differentiation blockade in MS. [ABSTRACT FROM AUTHOR]

Heterometal‐doped gold clusters are poorly accessible through wet‐chemical approaches and main‐group‐metal‐ or early‐transition‐metal‐doped gold clusters are rare. Compounds [M(AuPMe3)11(AuCl)]3+ (M=Pt, Pd, Ni) (1–3), [Ni(AuPPh3)(8−2n)(AuCl)3(AlCp*)n] (n=1, 2) (4, 5), and [Mo(AuPMe3)8 (GaCl2)3(GaCl)]+ (6) were selectively obtained by the transmetalation of [M(M′Cp*)n] (M=Mo, E=Ga, n=6; M=Pt, Pd, Ni, M′=Ga, Al, n=4) with [ClAuPR3] (R=Me, Ph) and characterized by single‐crystal X‐ray diffraction and ESI mass spectrometry. DFT calculations were used to analyze the bonding situation. The transmetalation proved to be a powerful tool for the synthesis of heterometal‐doped gold clusters with a design rule based on the 18 valence electron count for the central metal atom M and in agreement with the unified superatom concept based on the jellium model. [ABSTRACT FROM AUTHOR]

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Heterometalldotierte Goldcluster sind durch nasschemische Synthese schwer zugänglich, und mit Hauptgruppenmetallen oder frühen Übergangsmetallen dotierte Cluster sind rar. Die Verbindungen [M(AuPMe3)11(AuCl)]3+ (M=Pt, Pd, Ni) ( 1- 3), [Ni(AuPPh3)(8-2 n)(AuCl)3(AlCp*) n] ( n=1, 2) ( 4, 5) und [Mo(AuPMe3)8(GaCl2)3(GaCl)]+ ( 6) wurden selektiv durch Transmetallierung von [M(M′Cp*) n] (M=Mo, E=Ga, n=6; M=Pt, Pd, Ni, M′=Ga, Al; n=4) mit [ClAuPR3] (R=Me, Ph) hergestellt und mit Einkristallröntgenbeugung sowie ESI-MS charakterisiert. Mithilfe von DFT-Rechnungen wurden die Bindungsverhältnisse analysiert. Die Transmetallierung ist eine wirkungsvolle Syntheseroute hin zu heterometalldotierten Goldclustern, deren Aufbau der 18-Valenzelektronenregel für das Zentralmetallatom gehorcht und die mit dem Superatomkonzept auf Grundlage des Jellium-Modells übereinstimmen. [ABSTRACT FROM AUTHOR]

Heterometal‐doped gold clusters are poorly accessible through wet‐chemical approaches and main‐group‐metal‐ or early‐transition‐metal‐doped gold clusters are rare. Compounds [M(AuPMe3)11(AuCl)]3+ (M=Pt, Pd, Ni) (1–3), [Ni(AuPPh3)(8−2n)(AuCl)3(AlCp*)n] (n=1, 2) (4, 5), and [Mo(AuPMe3)8 (GaCl2)3(GaCl)]+ (6) were selectively obtained by the transmetalation of [M(M′Cp*)n] (M=Mo, E=Ga, n=6; M=Pt, Pd, Ni, M′=Ga, Al, n=4) with [ClAuPR3] (R=Me, Ph) and characterized by single‐crystal X‐ray diffraction and ESI mass spectrometry. DFT calculations were used to analyze the bonding situation. The transmetalation proved to be a powerful tool for the synthesis of heterometal‐doped gold clusters with a design rule based on the 18 valence electron count for the central metal atom M and in agreement with the unified superatom concept based on the jellium model. [ABSTRACT FROM AUTHOR]

A simple imine clip-and-cleave concept has been developed for the selective hydroxylation of non-activated CH bonds in aliphatic aldehydes with dioxygen through a copper complex. The synthetic protocol involves reaction of a substrate aldehyde with N,N-diethyl-ethylendiamine to give the corresponding imine, which is used as a bidentate donor ligand forming a copper(I) complex with [Cu(CH 3 CN) 4 ][CF 3 SO 3 ]. After exposure of the reaction mixture to dioxygen acidic cleavage and aqueous workup liberates the corresponding β-hydroxylated aldehyde. The concept for the hydroxylation of trimethylacetaldehyde as well as adamantane and diamantane 1-carbaldehydes was investigated and the corresponding β-hydroxy aldehydes were obtained with high selectivities. The results of low temperature stopped-flow measurements indicate the formation of a bis(μ-oxido)dicopper complex as reactive intermediate. According to density functional theory (DFT, RI-BLYP-D3/def2-TZVP(SDD)/ COSMO(CH 2 Cl 2 )//RI-PBE-D3/def2-TZVP(SDD)) computations CH bonds suitably predisposed to the [Cu 2 O 2 ] 2+ core undergo hydroxylation in a concerted step with particularly low activation barriers, which explains the experimentally observed regioselectivities., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The regio- and stereoselective copper-mediated hydroxylation of a non-activated aliphatic C-H bond in steroids by dioxygen, initially reported by Schönecker et al. (Angew. Chem. Int. Ed. 2003, 42, 3240-3244), has recently evolved into a valuable synthetic tool. In the present work, a detailed mechanistic density functional theory (DFT) study addressing the origin of the remarkable selectivity of Schönecker's reaction is reported. The applied BLYP-D3/def2-TZVP(SDD) level of DFT is benchmarked against experimental and coupled-cluster reference data. The resulting mechanistic scenario involves formation of a bis-μ-oxo dicopper complex as key intermediate. In this complex three C-H bonds of the pendant steroid ligand are predisposed towards intramolecular activation by the bis-μ-oxo dicopper core. The lowest activation barrier (12.0 kcal mol -1 ) is computed for β-hydroxylation at the C12 position, in agreement with the experimental observations. Natural bond orbital (NBO) analysis reveals stabilizing orbital interactions that favor the β-hydroxylation pathway over competing reaction channels., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Heterometal-doped gold clusters are poorly accessible through wet-chemical approaches and main-group-metal- or early-transition-metal-doped gold clusters are rare. Compounds [M(AuPMe3 )11 (AuCl)](3+) (M=Pt, Pd, Ni) (1-3), [Ni(AuPPh3 )(8-2n) (AuCl)3 (AlCp*)n ] (n=1, 2) (4, 5), and [Mo(AuPMe3 )8 (GaCl2 )3 (GaCl)](+) (6) were selectively obtained by the transmetalation of [M(M'Cp*)n ] (M=Mo, E=Ga, n=6; M=Pt, Pd, Ni, M'=Ga, Al, n=4) with [ClAuPR3 ] (R=Me, Ph) and characterized by single-crystal X-ray diffraction and ESI mass spectrometry. DFT calculations were used to analyze the bonding situation. The transmetalation proved to be a powerful tool for the synthesis of heterometal-doped gold clusters with a design rule based on the 18 valence electron count for the central metal atom M and in agreement with the unified superatom concept based on the jellium model., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)