BRIDGEHEAD CARBOCATIONS - CORRELATION BETWEEN MP2/6-31G-ASTERISK CATION ENERGIES OF SOME CAGED CATIONS AND THE SOLVOLYSIS RATES OF THEIR PRECURSOR TRIFLATES

Synthesis of the series of caged systems, 4-homocubyl triflate (7), 1-homocubyl triflate (10), 6-tricyclo[3.1.1.0(3,6)]heptyl (norcubyl) triflate (11), and 6-tricyclo[3.2.1.0(3,6)]octyl triflate (12) together with 1-norbornyl triflate (9) is described. Examination of their behavior under solvolysis conditions in 80% ethanol shows that in each case ionization occurs to give the corresponding bridgehead cation and that there is an enormous difference in reactivity between the triflates. A linear correlation is observed when the logarithm of the ionization rates of the triflates 7 and 9-12 as well as that of cubyl trinate (8) are plotted against the MP2-derived energies of the corresponding bridgehead cations.