ISSN:
0894-3230
Keywords:
Chemistry
;
Theoretical, Physical and Computational Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Adamantane and 1,3,5,7-tetradeuterioadamantane were oxidized by RuO4 in two solvent systems, CCl4-CH3CN-H2O and acetone-water, yielding two kinetic deuterium isotope effects (KIEs), 4·8 ± 0·2 and 7·8 ± 0·1, respectively, very similar to those obtained in analogous reactions with cis-decalin and perdeuterio-cis-decalin, 4·8 and 6·8. These results were interpreted as primary KIEs and small or negligible secondary KIEs. From this, sp2-hybridized intermediates were not involved in the reaction path. The kinetic effect of the solvent was investigated by performing the reaction in aqueous acetone and acetonitrile. The rates were correlated with Grunwald-Winstein Y values and with Reichardt ET (30) values. Both correlations showed the reaction to be only moderately dependent on the solvent polarity. 1-Substituted adamantanes were oxidized in CCl4-CH3CN giving a Taft ρ* value of -2·5 ± 0·1. These results were regarded as support for a reaction consisting of a pre-equilibrium with formation of a substrate-RuO4 complex followed by a rate-determining concerted reaction. The results did not support a reaction mechanism with a carbocation or radical intermediate, or a scheme with two competing reactions, one with a carbocation intermediate and the other with a concerted mechanism.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
