Steric Control of Geminal Lewis Pair Behavior: Frustration Induced Dyotropic Rearrangement

A series of methylene-linked boron/nitrogen geminal Lewis pairs were synthesized and the impacts of sterical effect on their chemical behavior were systematically investigated. Increasing the steric demand around the boron atom is manifested first by an incremental change in the structure of the resulting dative adducts. Accordingly, in the case of phenyl substituents (Alk(2)NCH(2)BPh(2)), formation of head-to-tail dimers/oligomers was observed, while such an intermolecular association was avoided when o-tolyl moiety was introduced [Alk(2)NCH(2)B(o-Tol)(2)], affording only an intramolecular dative complex. Further increase of sterical hindrance to a point (i.e. using mesityl substituents), however, caused a radical change in the structure; a dyotropic rearrangement occurred. Thus, steric interference induced a rearrangement in the geminal pair to relieve or minimize the frustration strain

Developing of antioxidant-enriched apple juice with elderberry (Sambucus Nigra L.) pomace

The aim of this study to develop a healthy enriched apple juice and utilization of by-product of elderberry pomace. The elderberries and their pomace contain high biological activity components, primarily polyphenols, anthocyanins, flavanols which compounds are known to have potential antioxidant properties. In this study the most efficiently extraction method was explored by using different solvents and using the chosen best method, our goal is to develop a delicious enriched apple juice with contain this pomace extracts

Single-Center, but Multipotent Lewis acids: Illuminating the Multiple Lewis Acidity of Triaryl-Boranes via Atropisomeric Dative Adducts

We report the illumination of the exotic and peculiar molecular phenomenon of single-centered, but multiple Lewis acidity for triaryl boranes with fine-tuned steric effects and appropriate symmetry design. The existence of this unique molecular property was indirectly confirmed by the formation of B(sp3)–N(sp3) atropisomeric piperidine–borane adducts using state-of-the-art NMR techniques in combination with computational methods. Additional 19F EXSY experiments also revealed that these sterically strained piperidine–borane adducts display conformational interconversions, which take place via dissociative rather than rotameric mechanism