THERMAL-REACTIONS OF N-ACYL PHENYLCYCLOBUTYLIMINES

Flash vacuum thermolysis of the parent and phenyl substituted N-acyl c yclobutylimines 3 was under investigation. At 500 degrees C and 0.01 t orr, 3d with phenyl group on C-1 and 3e with phenyl group on C-2 of cy clobutane ring underwent ring expansion processes to produce N-acyl 1, 2,3,4-tetrahydropyridines 8d and 8e. Meanwhile the parent N-acyl cyclo butylimines 3a together with the phenyl group on C-3 (3c) and imine ca rbon (3b) proceeded a hydrogen shift reaction to afford N-acylaminomet hylenecyclobutanes 8a-c. In addition, cycloreversion competed with rin g expansion or hydrogen shift in all cases.