6221-75-6Relevant articles and documents
Solvolyis of 1-Adamantyl Nitrate. Y(ONO2) Scale and Product Partitioning in Aqueous Ethanol
Kevill, Dennis N.,Hawkinson, David C.
, p. 5394 - 5399 (1990)
The specific rate of solvolysis of 1-adamantyl nitrate has been measured for four solvents over a range of temperature, including 50.0 deg C, and for 30 additional solvents at 50.0 deg C.Autocatalysis is observed only in 100percent 2,2,2-trifluoroethanol, and this can be removed by addition of pyridine.A scale of solvent ionizing power values (YONO2) is developed in terms of Grunwald-Winstein equation.The YONO2 values correlate well with previously determined YOTs values, with a slope of close to unity.In aqueous ethanol, attack by water is favored.A selectivity value of 1.96 +/- 0.04 is observed in the 90-60percent ethanol range, falling slightly in value in more aqueous mixtures; possible explanations for this fall are discussed.
Multiple Pathways in the Solvolysis of 1-Adamantyl Fluoroformate
Kevill, Dennis N.,Kyong, Jin Burm
, p. 258 - 265 (2007/10/02)
Reactions of 1-adamantyl fluoroformate in hydroxylic solvents have been studied.In solvents of high ionizing power and relatively low nucleophilicity, such as 2,2,2-trifluoroethanol-water mixtures, the reactions parallel those of 1-adamantyl chloroformate, and only solvolysis-decomposition reaction is observed.However, differing from the reactions of the corresponding chloroformate, in other solvents appreciable amounts pf attack at acyl carbon occur, more than 90percent in 80percent aqueous ethanol.Entropies of activation for attack at acyl carbon are considerably more negative than for solvolysis-decomposition.For the solvolysis-decomposition, a Grunwald-Winstein m value of 0.70 is observed.The kCl/kF ratios for solvolysis-decomposition are in the range of 104-105, suggesting appreciable C-X bond breaking in the transition state of the rate-determining step and arguing against rate-determining formation of a 1-Ad(1+)(OCOX)(1-) ion pair.Attack at acyl carbon is analyzed in terms of the two-term Grunwald-Winstein equation, and sensitivities toward changes in nucleophilicity and ionizing power are identical to those for solvolyses of n-octyl fluoroformate, which are believed to proceed via a tetrahedral intermediate.For each of the major pathways, selectivities toward the components of binary hydroxylic solvents are reported and discussed.
Relative Reactivity of Bridgehead Adamantyl and Homoadamantyl Substrates from Solvolyses with Heptafluorobutyrate as a Highly Reactive Carboxylate Leaving Group. Absence of SN2 Character of Solvolysis of tert-Butyl Derivatives
Farcasiu, Dan,Jaehme, Joachim,Ruechardt, Christoph
, p. 5717 - 5722 (2007/10/02)
Heptafluorobutyrates, conveniently prepared from alcohols, possess a reactivity similar to that of halides in solvolysis reactions.A product and isotope distribution study for the reaction of 1-adamantyl heptafluorobutyrate (1a) in 80:20 ethanol-H2(18)O demonstrated exclusive alkyl-oxygen cleavage.The reactivities of 1a, 1-(2a), and 3-homoadamantyl heptafluorobutyrate (3a) increase with the flexibility of the hydrocarbon skeleton.The rate constants are linearly correlated with the strain increase upon ionization.No acceleration attributable to nucleophilic solvent assistance was evidenced for the tert-butyl ester, 4a.A literature proposal for such assistance in solvolyses of 4 is examined.The existing data are explained better by an SN1 process with electrophilic assistance of the leaving group in the solvents that can form very strong hydrogen bonds.
