Pyrolyses of o-alkoxy- and o-alkylthio-N-allylanilines and of some related O-and S-allyl compounds

The o-substituted allyl compounds (1)–(12) have been pyrolysed in order to generate aminyl, phenoxyl, and thiophenoxyl radicals with adjacent substituents. In all cases, products are formed by intramolecular hydrogen transfer from the substituent to the radical centre. This process may be followed by rearrangement to give an aldehyde, by heteroatom extrusion to give an alkene, or by ring formation to give five-membered ring heterocycles (Scheme 1, routes A, B1, and B2 respectively). The distribution of products formed by each route is dependent both on the nature of the o-substituent, and on the nature of the initial radical.