THERMOLYSIS OF ALLYLIC AZOALKANES

The synthesis and thermolysis kinetics of five new allylic azoalkanes are described in detail. The effect of one and two bridgehead vinyl groups (compounds 3 and 4) on the rate of nitrogen loss from 2,3-diazabicyclo-[2.2.2]oct-2-ene suggests that 3 decomposes by simultaneous but asynchronous C-N bond stretching. On the other hand, the symmetrical compounds 1 and 4 probably follow the synchronous bond-breaking pathway. Thermolysis rates for three allylic azoalkanes (5,6, and 9) were found to be very similar to that of known compound 2. Thus neither considerable geometric distortion of the olefin nor addition of alkyl groups beyond two has much effect on allylic radical stability. The similarity of 2 and 9 may arise from a previously predicted saturation effect. © 1979, American Chemical Society. All rights reserved.