75295-96-4Relevant academic research and scientific papers
Solvolytic studies in cycloalkyl systems
Ranganayakulu,Murthy
experimental part, p. 307 - 313 (2012/04/04)
The angular dependence of the C-H/C-D bond for a stabilization of the developing carbonium ion in the transition state of the solvolysis reaction of cycloalkyl halides has been investigated. This has been achieved by studying the rate of solvolysis of eight cyclic β-deuterated 1-alkyl-1-chloro cycloalkanes. Reaction rates for the solvolysis of both β-C-H and of the corresponding β-C-D compounds have been determined and the difference in the rate ratio i.e. kH/kD was attributed to the differential hyperconjugative effects exerted by β-hydrogens in different ring systems. By varying the ring size from C5 to C12 the dihedral angle of C-H bond in relation to the vacant "p" orbital on the trigonal carbon, (carbonium ion transition state) changes leading to changes in hyperconjugative stabilization of the intermediate carbonium ion with a consequent change in the rate of solvolysis. β-Deuterium isotope effects thus obtained for different cyclic systems were related with the actual bond angles between β-C-H bonds and the developing carbonium ions. Using the Allinger's force field calculations the best geometry for both the carbonium ions and the starting halo hydrocarbons were calculated.
