J . Am. Chem. SOC.1983, 105, 3961-3966 systems such as 8 is relieved by formation of a small ring. It follows from this that the 2-dichloromethyl- 1,3-dioxolenium ion, 14, should be more stable than its acyclic counterparts, 15, and
[01 + 0
C I >H-c CI
e.
14
OR
CI
OR
15
CI
’
the case: kH+for 16 is reported as 104 M-’ which is 20-30 times greater than the rate constants for the acyclic dichloroketene acetals determined here. Registry No. 2, 5634-54-8; 3, 61543-76-8; 4 (R = CH,), 69814-51-3; 4 (R = CzH,), 54567-93-0; 4 (R = C3H7), 85390-96-1; H3O*, 13968-
\c=c/o]
4
C I C‘C ” SO2 > FSO,/SbFS > SO2ClF.
Conclusions Protonation on both termini of diazomethane can be observed only under conditions of kinetic control in extremely acidic solutions, when the acidity is reduced only the thermodynamically more stable C-protonated isomer can be seen. Loss of nitrogen from the methanediazonium ion is nucleophile assisted in the very highly acidic medium of H0SO2F/SbF5/SO2ClF. The effect of substituents on both of these fundamentally important reactions is under experimental and theoretical investigation in our laboratories. Acknowledgment. W e thank the Swiss National Science Foundation for financial support and Professors H. Dahn and R. Huisgen for very stimulation discussions and comments. Registry NO.1, 20404-06-2; 2, 16064-33-8; 3,421-20-5; 6,8561 1-60-5; 7, 8561 1-61-6;CH,=N2, 334-88-3;CH*DN2’, 85565-61-3;CH2= N+=ND, 85554-54-7;CH2DOSOZF, 85554-55-8; CH,=N=”N, 52937-22-1;CH,=”N=N, 52937-21-0.
