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Simple copper salts serve as catalysts to effect C–X bond-forming reactions in some of the most utilized transformations in synthesis, including the oxidative coupling of aryl boronic acids and amines. However, these Chan–Lam coupling reactions have historically relied on chemical oxidants that limit their applicability beyond small-scale synthesis. Despite the success of replacing strong chemical oxidants with electrochemistry for a variety of metal-catalyzed processes, electrooxidative reactions with ligandless copper catalysts are plagued by slow electron-transfer kinetics, irreversible copper plating, and competitive substrate oxidation. Herein, we report the implementation of substoichiometric quantities of redox mediators to address limitations to Cu-catalyzed electrosynthesis. Mechanistic studies reveal that mediators serve multiple roles by (i) rapidly oxidizing low-valent Cu intermediates, (ii) stripping Cu metal from the cathode to regenerate the catalyst and reveal the active Pt surface for proton reduction, and (iii) providing anodic overcharge protection to prevent substrate oxidation. This strategy is applied to Chan–Lam coupling of aryl-, heteroaryl-, and alkylamines with arylboronic acids in the absence of chemical oxidants. Couplings under these electrochemical conditions occur with higher yields and shorter reaction times than conventional reactions in air and provide complementary substrate reactivity.

The direct and scalable electroreduction of triphenylphosphine oxide (TPPO)-the stoichiometric byproduct of some of the most common synthetic organic reactions-to triphenylphosphine (TPP) remains an unmet challenge that would dramatically reduce the cost and waste associated with performing desirable reactions that are mediated by TPP on a large scale. This report details an electrochemical methodology for the single-step reduction of TPPO to TPP using an aluminum anode in combination with a supporting electrolyte that continuously regenerates a Lewis acid from the products of anodic oxidation. The resulting Lewis acid activates TPPO for reduction at mild potentials and promotes P-O over P-C bond cleavage to selectively form TPP over other byproducts. Finally, this robust methodology is applied to (i) the reduction of synthetically useful classes of phosphine oxides, (ii) the one-pot recycling of TPPO generated from a Wittig reaction, and (iii) the gram-scale reduction of TPPO at high concentration (1 M) with continuous product extraction and in flow at high current density.

The crystal structures of the title compounds, C19H19NO and C31H34N2O, were determined as part of an experiment in an undergraduate teaching laboratory that demonstrates the relationship between molecular structure and function. 1′,3′,3′-Trimethylspiro[chromene-2,2′-indoline] is both a photoswitch and thermochromic molecule. Students synthesized it and a bis-indoline adduct and compared the crystallographically determined structures to computed gas-phase models.

The crystal structures of the title compounds were determined as part of an experiment in an undergraduate teaching laboratory that demonstrates the relationship between mol­ecular structure and function. 1′,3′,3′-Tri­methyl­spiro­[chromene-2,2′-indoline] is both a photoswitch and thermochromic mol­ecule. Students synthesized it and a bis-indoline adduct and compared the crystallographically determined structures to computed gas-phase models., The crystal structures of the title compounds, C19H19NO and C31H34N2O, were determined as part of an experiment in an undergraduate teaching laboratory that demonstrates the relationship between mol­ecular structure and function. 1′,3′,3′-Tri­methyl­spiro­[chromene-2,2′-indoline] is both a photoswitch and thermochromic mol­ecule. Students synthesized it and a bis-indoline adduct and compared the crystallographically determined structures to computed gas-phase models.

Physical exercise classification method by hidden Markov model (HMM) is considered in this study. The aim of this study is to discuss the availability of HMM based motion modeling in order to compare human skills. In this paper, a preprocessing technique for observed human motion by self-organizing map (SOM) to label a motion characteristic is proposed. Then, HMM construction method by using genetic algorithm (GA) with Baum-Welch algorithm, modified crossover and mutation is introduced. Simulation studies are carried out for bat swing motions. It is shown that the proposed approach has an ability to recognize bat swing motions

Synthesis of substituted phenylacetylide ligands 2,6-bis(trimethylsilyl)phenylacetylene (H1) and 2-(triphenylsilyl)phenylacteylene (H2) is reported. Ligand 1 supports tetrahedral complexes of V(III), Fe(II), and Mn(II) (3-5). Complexes 3-5 are high-spin and redox active.