Rearrangement of 2-iodo-3-perfluoroalkyl-1-propyl acetates to 1-iodo-3-perfluoroalkyl-2-propyl acetates

Abstract

2-Iodo-3-perfluoroalkylpropyl acetates, R FCH 2CHICH 2OAc ( 1) (R F = i-C 3F 7, C 4F 9, C 6F 13, C 8F 17), have been rearranged thermally to 1-iodo-3-perfluoroalkyl-2-propyl acetates, R FCH 2CH(OAc)CH 2I ( 2), in 89% yield over the temperature range 120–200 °C. The results indicate that the rearrangement is a reversible process which is shifted towards the formation of 2. The equilibrium regio isomer ratio ( 1 2 = 1:8) was independent of the temperature and of the nature of the R F substituent. It is proposed that the rearrangement proceeds through a free-radical mechanism including 1,2-migration of the acetoxy group after thermal scission of the CI bond.