Possible neighbouring group participation of a nitro-group in the conversion of 3-hydroxymethyl-2-(2-nitrophenyl)-1,2,3,4-tetrahydroisoquinoline into its 3-chloromethyl derivative

The alcohol 12 reacted with 4-toluenesulfonyl chloride in boiling dichloromethane solution to give the chlorinated product 13 rather than the expected tosylate 3 by a mechanism that could involve neighbouring group participation of the nitro-substituent. In contrast, the isomeric alcohol 15 reacted normally with 4-toluenesulfonyl chloride giving the tosylate 16 under similar conditions.