Thermal decomposition of 9-(substituted phenylimino)-1,4-dihydro-1,2,3,4-tetraphenyl-1,4-methanonaphthalenes
Abstract
Addition of benzyne to the tetraphenylcyclopentadienone anils (4a–f) gives the 9-(substituted phenylimino)-1,4-dihydro-1,2,3,4-tetraphenyl-1,4-methanonaphthalenes (5a–f) which on thermolysis eliminate the phenyl isocyanides (6a–f). By following the appearance of isocyanide the relative rates of decomposition in toluene at 120·0° are (5a) : (5b) : (5c) : (5d) : (5e) : (5f)= 2·20 : 1·69 : 1·00 : 0·26 : 0·18 : 1·19 and lead to the conclusion that elimination is slow by comparison with the rate of inversion at nitrogen.