Interrogating Pd(II) Anion Metathesis Using a …

Abstract Asymmetric hydrogenation of N-hetero aromatics offers a very straightforward and efficient method to obtain the corresponding chiral N-hetero cyclic saturated or partially saturated compounds. As one of the most challenging substrates, asymmetric hydrogenation of isoquinolines has met with limited success probably because of lower reactivity and the catalyst deactivation resulted from strong coordination. Considering the prevalence of the chiral 1,2,3,4-tetrahydroisoquinoline motif in natural alkaloids and drug molecules, the development of new catalyst system for asymmetric hydrogenation of isoquino-lines is highly desirable and significant. Herein, a novel chiral anion metathesis strategy successfully applied for asymmetric transfer hydrogenation of isoquinolines is reported. N-Protected 1-substituted 1,2-dihydroisoquinolines were obtained with high yield and up to 79 % ee in the presence of Hantzsch ester and chloroformate using chiral phosphoric acid as catalyst. The phosphate salt and the activated N-acyl isoquinolinium chloride undergo anion metathesis to form chiral contact ion pair,

Anion metathesis in ionic silica nanoparticle networks

T1 - An anion metathesis approach to amphiphilic. Photoluminescent block ionomers

19/12/2017 · Anion metathesis in..

AB - Ion pair receptor 3 bearing an anion binding site and multiple cation binding sites has been synthesized and shown to function in a novel binding-release cycle that does not necessarily require displacement to effect release. The receptor forms stable complexes with the test cesium salts, CsCl and CsNO 3, in solution (10% methanol-d 4 in chloroform-d) as inferred from 1H NMR spectroscopic analyses. The addition of KClO 4 to these cesium salt complexes leads to a novel type of cation metathesis in which the "exchanged" cations occupy different binding sites. Specifically, K + becomes bound at the expense of the Cs + cation initially present in the complex. Under liquid-liquid conditions, receptor 3 is able to extract CsNO 3 and CsCl from an aqueous D 2O layer into nitrobenzene-d 5 as inferred from 1H NMR spectroscopic analyses and radiotracer measurements. The Cs + cation of the CsNO 3 extracted into the nitrobenzene phase by receptor 3 may be released into the aqueous phase by contacting the loaded nitrobenzene phase with an aqueous KClO 4 solution. Additional exposure of the nitrobenzene layer to chloroform and water gives 3 in its uncomplexed, ion-free form. This allows receptor 3 to be recovered for subsequent use. Support for the underlying complexation chemistry came from single-crystal X-ray diffraction analyses and gas-phase energy-minimization studies.

A New Method for Anion Metathesis - …

N2 - Ion pair receptor 3 bearing an anion binding site and multiple cation binding sites has been synthesized and shown to function in a novel binding-release cycle that does not necessarily require displacement to effect release. The receptor forms stable complexes with the test cesium salts, CsCl and CsNO 3, in solution (10% methanol-d 4 in chloroform-d) as inferred from 1H NMR spectroscopic analyses. The addition of KClO 4 to these cesium salt complexes leads to a novel type of cation metathesis in which the "exchanged" cations occupy different binding sites. Specifically, K + becomes bound at the expense of the Cs + cation initially present in the complex. Under liquid-liquid conditions, receptor 3 is able to extract CsNO 3 and CsCl from an aqueous D 2O layer into nitrobenzene-d 5 as inferred from 1H NMR spectroscopic analyses and radiotracer measurements. The Cs + cation of the CsNO 3 extracted into the nitrobenzene phase by receptor 3 may be released into the aqueous phase by contacting the loaded nitrobenzene phase with an aqueous KClO 4 solution. Additional exposure of the nitrobenzene layer to chloroform and water gives 3 in its uncomplexed, ion-free form. This allows receptor 3 to be recovered for subsequent use. Support for the underlying complexation chemistry came from single-crystal X-ray diffraction analyses and gas-phase energy-minimization studies.

Topochemical anion metathesis routes to the Zr2N2S …

and and and and and (2000)Radical anion forming activity of the Grubbs' catalyst and related organometallics: Michael acceptors as metathesis promoters. Journal of Organometallic Chemistry, 606 (1). pp. 84-87. ISSN 0022-328X

Chapter 4 - Metathasis Reactions

A novel rotaxane containing a meta-xylenediamide macrocycle is prepared by a new clipping methodology. Upon anion metathesis to the non-coordinating hexafluorophosphate salt, the rotaxane host system was shown to bind chloride and bromide anions more strongly than the basic oxoanions dihydrogen phosphate and acetate in the competitive solvent system 1:1 CDCl(3):CD(3)OD.

Metathesis Reactions - University of Waterloo

Furthermore, it is shown that performing ring-closing metathesis reactions on some of these pseudorotaxane assemblies gives novel catenane species 14 and 15, in which the yield of interlocked molecule obtained is critically dependent on the presence of a suitable anion template, namely, chloride.