Cycloheptatriene and tropylium metal complexes. Part IV. Preparation of 7-exo-substituted tricarbonylcycloheptatrienechromiums
作者:P. L. Pauson、G. H. Smith、J. H. Valentine
DOI:10.1039/j39670001057
日期:——
The 7-exo-configuration is assigned to all substituted tricarbonylcycloheptatrienechromiums previously prepared by the “normal” reaction of tricarbonyltropyliumchromium salts with anions. Several new examples are described, and displacement of methoxide from tricarbonyl-7-exo-methoxycycloheptatrienechromium is shown to be an advantageous alternative route to these products.
Cycloheptatriene and tropylium metal complexes. Part V. 7-endo-Substituted tricarbonylcycloheptatrienechromiums
作者:P. L. Pauson、G. H. Smith、J. H. Valentine
DOI:10.1039/j39670001061
日期:——
Reaction of 7-substituted cycloheptatrienes with either hexacarbonylchromium or with tricarbonyltripyridine-chromium leads to the corresponding 7-endo-substituted tricarbonylcycloheptatrienechromiums, either exclusively or, in only two of the cases studied, mixed with the exo-isomer. Some new observations on the ring-contraction of such complexes are reported.
Cycloheptatrienyl radicals: An EPR study of substituent effects
作者:Finlay MacCorquodale、John C. Walton
DOI:10.1002/mrc.1260280415
日期:1990.4
acceptor substituents were generated by hydrogen abstraction from the corresponding cycloheptatrienes and studied by EPR spectroscopy. The barrier to rotationabout the C‐1CO bond in ethoxycarbonylcycloheptatrienyl radicals was found to be ca. 7.5 kcal mol−1 (31.4 kJ mol−1). The observed hyperfine splittings of the ring hydrogens were interpreted in terms of a model in which the substituent causes