The current state-of-the-art synthesis for the formation of enantiomerically enriched all-carbon quaternary stereocenters in acyclic system relies on the formation of a single carbon-carbon bond per chemical step by asymmetric catalysis. These extraordinary sophisticated methods were logically classified among the most powerful and innovative ones. In this concept article, we are proposing a new retrosynthetic
Infrared spectra of CH3–MH, CH3–M, and CH3–MH− prepared via methane activation by laser-ablated Au, Ag, and Cu atoms
作者:Han-Gook Cho、Lester Andrews
DOI:10.1039/c0dt01827a
日期:——
Methane activation by laser-ablated, excited Group 11 metal atoms has been carried out, leading to generation of CH3âMH, CH3âM, and CH3âMHâ, which are identified in the product infrared spectra on the basis of isotopic shifts and correlation with DFT calculated frequencies. The products reveal that CâH insertion by excited Au, Ag, and Cu readily occurs, and subsequent hydride-detachment or electron addition also follows. Each type of product has similar photochemical properties regardless of the metal. DFT computed energies reveal facile hydride dissociation and high electron affinities for the insertion complexes. The methyl metal species have the shortest CâM bonds, consistent with their highest calculated effective bond order, and the CH3âMH complexes have higher electron affinities than the metal atoms.
Activation of methane by photoexcited copper atoms and the photochemistry of methylcopper hydride in solid methane matrixes
作者:J. Mark Parnis、Steven A. Mitchell、Jaimie Garcia-Prieto、Geoffrey A. Ozin
DOI:10.1021/ja00312a060
日期:1985.12
The interaction of arsenite with oxidized, partially reduced, and fully reduced forms of xanthine oxidase has been studied by X-ray absorption spectroscopy at the arsenic and molybdenum K edges. Clear evidence for a Mo-As interaction at 3.00 8, is observed in the molybdenum EXAFS of the fully reduced ternary complex consisting of xanthine oxidase, arsenite, and the inhibitor 8-bromoxanthine. An essentially