80054-67-7Relevant academic research and scientific papers
Solvolytic Reactions in Fluorinated Alcohols. Role of Nucleophilic and Other Solvation Effects
Bentley, T. William,Llewellyn, Gareth,Ryu, Zoon Ha
, p. 4654 - 4659 (2007/10/03)
Rate constants and products for solvolyses of chlorodiphenylmethane (Ph2CHCl) and p-methoxybenzyl chloride in 2,2,2-trifluoroethanol (TFE)/water and TFE/ethanol are reported, along with additional kinetic data for solvolyses of tert-butyl and other alkyl halides (RX) in 97% w/w TFE/water and in 97% w/w hexafluoropropan-2-ol/water (HFIP). Results are discussed in terms of the solvent ionizing power (Y) and the solvent nucleophilicity (N), and contributions from other solvation effects are considered. Comparisons with other SN1 solvolyses show that solvolyses of Ph2CHCl in TFE mixtures are unexpectedly fast, but product ratios are unexceptional. An additional solvation effect influences solvolyses leading to delocalized cations, and a delocalized cationic transition state for concerted elimination may explain the recent results of Takeuchi et al., (J. Org. Chem. 1997, 62, 4904) without the need to postulate additional specific solvation effects for adamantyl systems, such as Bronsted-base solvation of α- and β-hydrogen atoms; concerted elimination may occur because simple tertiary alkyl cations are too unstable to form in predominantly aqueous media. Iodide/bromide and bromide/chloride rate ratios are very similar for 1-adamantyl halides and corresponding solvolyses of tert-butyl halides; these ratios decrease in the order aq EtOH > TFE > HFIP, as expected for an electrophilic solvation effect (this effect can readily be incorporated into Y values). From kinetic data for a series of tertiary alkyl chlorides in 97% TFE/water, it is shown that the susceptibility of rates of solvolyses of RCl to N decreases with an increase in steric hindrance or with an increase in charge stabilization. Also, the small kinetic solvent isotope effects for typical solvolyses (e.g., methyl tosylate) indicate that nucleophilic attack lags behind heterolysis of the C-X bond.
Synthesis and Decomposition of the N-Alkyl-N-nitro-O-benzoylhydroxylamines
White, Emil H.,Reefer, John,Erickson, Ronald H.,Dzadzic, Petar M.
, p. 4872 - 4876 (2007/10/02)
Nitration of N-alkyl-O-benzoylhydroxylamines yields the correspondng N-nitro derivatives.At modest temperatures these compounds decompose to yield alkyl benzoates, alkenes, benzoic acid, and nitrous oxide.In the case of primary alkylnitrohydroxylamines, nitroalkanes and alkyl nitrates are also formed.The alkyl benzoates are products of ionic reactions since skeletal rearrangements characteristics of carbonium ions occur.The insensivity of the rates of decomposition to solvent polarity suggests that the rate-determining step is a rearrangement rather than direct ionization.
