17314-57-7Relevant academic research and scientific papers
Synthesis, properties and application of electronically-tuned tetraarylarsonium salts as phase transfer catalysts (PTC) for the synthesis of gem-difluorocyclopropanes
Grudzień, Krzysztof,Basak, Tymoteusz,Barbasiewicz, Micha?,Wojciechowski, Tomasz M.,Fedoryński, Micha?
supporting information, p. 106 - 110 (2017/04/11)
Preparation of gem-difluorocyclopropane from α-methylstyrene and chlorodifluoromethane was investigated under basic two-phase conditions. Although simple tetraalkylammonium salts appeared uneffective as phase-transfer catalysts (PTC) for this purpose, tetraphenylarsonium chloride displayed moderate activity, and inspired studies of the phenomena. To improve its efficiency we synthesized set of electronically-tuned tetraarylarsonium analogues. Their preparation revealed interesting exchange process of aryl substituents on the arsonium center, whereas activity studies demonstrated a correlation of catalytic efficiency with electronic effects of the substituents. Two of the tetraarylarsonium catalysts were characterized by X-ray studies.
An improved bidentate complex of iridium as a catalyst for hydrogen isotope exchange
Herbert, John M.,Kohler, Andrew D.,McNeill, Alan H.
, p. 285 - 294 (2007/10/03)
Iridium(I) complexes 1, containing bidentate phosphines, and 3, with arsine ligands, are generated in situ. These species mediate hydrogen isotope exchange in a variety of aromatic substrates including benzyl ketones. Although the catalytic activities of complexes 1 and 3 are generally unexceptional, a logical step leads to the use of [ethylene-1,2-bis(diphenylarsine)](cyclooctadiene) iridium(I) tetrafluoroborate (5), which is an efficient catalyst for both aryl and benzyl ketones, and mediates exchange to a substantial extent in other substrates also. Copyright
Methyl transfers. 14. Nucleophilic catalysis of nucleophilic substitution
McCortney,Jacobson,Vreeke,Lewis
, p. 3554 - 3559 (2007/10/02)
Nucleophiles X- can catalyze the substitution Nu- + RY → NuR + Y- by adding the faster pathway X- + RY → XR + Y- followed by Nu- + XR → RNu + X-. New examples include catalysis by I- of the exchange of methyl between two dialkyl sulfides and the transfer of methyl from an arsonium salt to a phosphine. The individual reactions are separately studied and some equilibrium information is presented. Iodide is ineffective in the transfer of methyl between two pnosphines, which is not detected with or without iodide. The Marcus equation treatment of this catalysis is shown to require that the identity transfer of R between two X- groups be far faster than that for transfer of R between two Nu- groups. Nucleophiles other than I- are discussed. The possibility that some "supernucleophiles" may have fast identity rates is discussed, and literature evidence that this is indeed the case is presented. Stereochemical studies using chiral methyl derivatives have shown that vitamin B12 does provide a nucleophilic catalysis to methyl transfer in living systems. Thus, the apparently superfluous participation of B12 in some biological methyl transfers is explained.
