Defluoroalkylation of Trifluoromethylarenes with Hydrazones: Rapid Access to Benzylic Difluoroarylethylamines.

Here, we report an efficient and modular approach toward the formation of difluorinated arylethylamines from simple aldehyde-derived N,N-dialkylhydrazones and trifluoromethylarenes (CF3-arenes). This method relies on selective C-F bond cleavage via reduction of the CF3-arene. We show that a diverse set of CF3-arenes and CF3-heteroarenes react smoothly with a range of aryl and alkyl hydrazones. The ß-difluorobenzylic hydrazine product can be selectively cleaved to form the corresponding benzylic difluoroarylethylamines.

Synthesis of Spirocyclic Piperidines by Radical Hydroarylation.

Reported here are conditions for the construction of spirocyclic piperidines from linear aryl halide precursors. These conditions employ a strongly reducing organic photoredox catalyst in combination with a trialkylamine reductant to achieve formation of aryl radical species. Regioselective cyclization followed by hydrogen-atom transfer affords a range of complex spiropiperidines. This system operates efficiently under mild conditions without the need for toxic reagents or precious metals.

Radical α-C-H Cyclobutylation of Aniline Derivatives.

A catalytic system has been developed for the direct alkylation of α-C-H bonds of aniline derivatives with strained C-C σ-bonds. This method operates through a photoredox mechanism in which oxidative formation of aminoalkyl radical intermediates enables addition to a bicyclobutane derivative, giving rise to α-cyclobutyl N-alkylaniline products. This mild system proceeds through a redox- and proton-neutral mechanism and is operational for a range of substituted arylamine derivatives.

One-pot synthesis of a ceria-graphene oxide composite for the efficient removal of arsenic species.

Arsenic contamination has posed a health risk to millions of people around the world. In this study, we describe a simple and facile one-step hydrothermal synthesis of a ceria-graphene oxide (ceria-GO) composite for the efficient removal of arsenic species. The prepared ceria-GO composite materials exhibited almost complete (over 99.99%) and quick removal of both arsenic species within 0.1 mg L-1 of the initial concentration. The calculated adsorption capacities were 185 mg g-1 for As(iii) and 212 mg g-1 for As(v). It was found that Ce3+ is an active site and continuously adsorbs arsenic species; there is a concomitant change from Ce4+ to Ce3+ due to the solution redox environment. This increase in the Ce3+ concentration further facilitates the complete removal of arsenic species in solution. Thus our approach offers a promising potential for the treatment of arsenic-contaminated drinking water.