Application of a Homogeneous Dodecakis(NCN‐PdII) Catalyst in a Nanofiltration Membrane Reactor under Continuous Reaction Conditions

A shape‐persistent nanosize dodecakis(NCN‐Pd^II‐aqua) complex ( 4b ) was applied as a homogeneous catalyst in the double Michael reaction between methyl vinyl ketone and ethyl α‐cyanoacetate under continuous reaction conditions in a nanofiltration membrane reactor. Due to its macromolecular dimensions, the catalyst is retained in the reactor (R=99.5% determined by ICP‐AAS) during catalysis. In addition, the catalyst was found to be stable under the continuous reaction conditions as a constant activity was obtained at prolonged reaction times (26 h, 65 exchanged reactor volumes). The turnover number of the catalyst was thus increased by a factor greater than 40 from 80 (batch) up to >3000 mol/mol Pd. Further development of this technology will allow an increase of the number of (industrial) catalytic processes in which homogeneous catalysts are applied.     

Utilization of 2‐(4‐Nitrophenylsulfonyl)ethoxycarbonyl (Nsc) as a Substitute for 9H‐Fluoren‐9‐ylmethoxycarbonyl (Fmoc) in Liquid Phase Chemistry

2‐(4‐Nitrophenylsulfonyl)ethoxycarbonyl (Nsc) is a useful substitute for the Fmoc group. It is easily removed not only with secondary amines but with tris(aminoethyl)amine (TAEA) and with resin‐bound TAEA, thus allowing for a simplified work‐up: the side products of the deprotection are removed either by extraction with phosphate buffer or by filtration.     

Acid‐Catalyzed Synthesis of α,β‐Disubstituted Conjugated Enones by a Meyer–Schuster‐Type Rearrangement in Allenols

A novel, direct and simple methodology to gain access to α,β‐disubstituted conjugated enones from α‐allenols in a sustainable metal catalysis context, considering the inexpensiveness and environmentally friendliness of iron(III) species and protons, has been developed.

     

Improved Synthesis of Pyrroles and Indoles via Lewis Acid‐Catalyzed Mukaiyama–Michael‐Type Addition/Heterocyclization of Enolsilyl Derivatives on 1,2‐Diaza‐1,3‐Butadienes. Role of the Catalyst in the Reaction Mechanism

The Mukaiyama–Michael‐type addition of various silyl ketene acetals or silyl enol ethers on some 1,2‐diaza‐1,3‐butadienes proceeds at room temperature in the presence of catalytic amounts of Lewis acid affording by heterocyclization 1‐aminopyrrol‐2‐ones and 1‐aminopyrroles, respectively. 1‐Aminoindoles have been also obtained by the same addition of 2‐(trimethylsilyloxy)‐1,3‐cyclohexadiene on some 1,2‐diaza‐1,3‐butadienes and subsequent aromatization. Mechanistic investigations indicate the coordination by Lewis acid of the enolsilyl derivative and its 1,4‐addition on the azo‐ene system of 1,2‐diaza‐1,3‐butadienes. The migration of the silyl group from a hydrazonic to an amidic nitrogen, its acidic cleavage and the final internal heterocyclization give the final products. Based on NMR studies and ab initio calculations, a plausible explanation for the migration of the silyl protecting group is presented.     

Palladium‐Catalyzed/Lewis Acid‐Promoted Alkene Dimerization and Cross‐Coupling with Alcohols via C?H Bond Activation

The cross‐couplings of alcohols to alkenes with the palladium/Lewis acid system are reported. This reaction occurs in a successive alkene dimerization, direct C H activation of alcohol and sp³ sp³ bond forming sequence via an interesting domino process.     

Walter Pichler's House Next to the Smithy: Atmosphere and Ground

Approaching atmosphere from a cultural perspective, Paul James explores conceptions of ground in a work by the Austrian architect, sculptor and draughtsman Walter Pichler. Where atmosphere relates to the critical strategy of clouding, to render obscure, to resist rhetorical clarity, Pichler's House Next to the Smithy, documented in drawings and photographs, highlights a link between weather and atmosphere, and darkness and interiority. Copyright © 2008 John Wiley & Sons, Ltd.     

Acceptance of technology related to healthcare among older Korean adults in rural areas: A mixed-method study

Many older adults find it difficult to accept new forms of information and communication technology (ICT), despite its advantages such as convenience and efficiency. It is necessary to identify the reasons for low ICT use among older people—even among those with positive attitudes toward ICT—to help older adults cope with social changes and bridge the digital divide. This study explored technology acceptance and related factors among older Korean adults living in rural areas. Based on an existing model (the senior technology acceptance model), a new conceptual framework for technology acceptance was proposed, and the framework was tested using pathway analysis. Semi-structured interviews were conducted in three focus groups (n = 15), and a survey questionnaire was administered to older Korean adults living in a rural area (n = 233) from 17 January 2021 to 18 February 2021. Qualitative data were analyzed using directed content analysis, and quantitative data were analyzed using pathway analysis. Four categories, 11 subcategories, and 18 codes were identified, and a new conceptual framework was proposed based on the qualitative findings. The results of the model revealed significant positive direct paths from external controls (β = 0.45, p < .001), attitudinal beliefs (β = 0.33, p < .001), and cognitive health (β = 0.10, p = .040) to internal abilities. It is necessary to develop and apply a targeted and tailored ICT education program to improve self-efficacy and reduce anxiety regarding technology use among older Korean adults living in rural areas.     

Synergy between Ni3Sn2 alloy and Lewis acidic ReOx enables selectivity control of furfural hydrogenation to cyclopentanone

Selectivity controlling is a crucial and challenging issue for the hydrogenation of furfural (FAL) to cyclopentanone (CPO). Herein, Ni₃Sn₂-ReO_x/TiO₂ is synthesized via successive impregnation and exhibits full conversion and 92.5 % CPO selectivity under 3.0 MPa H₂ at 140 °C, which are much higher than those of Ni/TiO₂ and Ni₃Sn₂/TiO₂. Characterizations show that Ni₃Sn₂ is the main active phase that remarkably restrains the over-hydrogenation of the furan ring, while ReO_x plays an electrophile or Lewis acid site to activate C-OH of furfuryl alcohol and induces its rearrangement. DFT calculations verify that Sn doping weakens the furan ring adsorption on Ni₃Sn₂ and shifts its adsorption configuration, which consequently inhibits side reactions and favors the metal-acid (Ni₃Sn₂-ReO_x) synergy. The catalyst is stable, recyclable and also active at even 0.5 MPa H₂ and 80 °C. This study provides an advanced strategy for the rational design of superior catalysts for tuning product selectivity, with practical potential for upgrading biomass-derived platform molecules.     

Polymer‐Supported Lewis Bases for the Baylis–Hillman Reaction

The use of polymer‐supported Lewis bases such as PEG₄₆₀₀‐(PPh₂)₂ and poly(DMAP) in the Baylis–Hillman reactions of N‐tosylimines (ArCHNTs) 1 or the corresponding arenecarbaldehydes with α,β‐unsaturated ketones has been investigated. The corresponding Baylis–Hillman adducts are obtained in good yields. The polymer‐supported Lewis bases can be easily recovered by filtration and the Lewis base PEG₄₆₀₀‐(PPh₂)₂ can be reproduced by reduction with LiAlH₄ and CeCl₃.     

Catalyzed Reactions of Enol Ethers with SN1 Active Groups: A Novel Method for the Preparation of α‐Alkylated Ketones

The performance of tert‐alkylations, alkoxyalkylations, and aldehyde enolate allylations proceeding with low catalyst loading (0.1 mol %–5 mol %) is described. The reactions are complete within short times and can even be performed without solvent and under ambient conditions. The mechanism of the reaction was investigated by deuterium labeling and cross‐over studies.