Nitroxide chemistry. Part 20. N,N-bis(trifluoromethyl)hydroxylamine as a carbocation trapping agent

Abstract

Aliphatic and alicyclic alkenes and alcohols react with an excess of N,N-bis(trifluoromethyl)hydroxylamine in the presence of either a catalytic or a stoicheiometric amount of 98% sulphuric acid to give (bistrifluoromethylaminooxy)-derivatives in good yields. Under the conditions of these reactions, products arising from carbocation rearrangement are obtained from cycloheptene, 1-methylcycloheptene, cyclo-octene, 1-methylcyclo-octene, 3-methylbutan-2-ol, 2-methylbut-1-ene, 2-methylpent-1-ene, and 4-methylpent-1-ene, but not from cyclopentene, 1-methylcyclopentene, cyclohexene, 1-methylcyclohexene, or norbornene. Norbornadiene gives 3-(bistrifluoromethylamino-oxy)nortricyclene as the major product, together with exo-5-(bistrifluoromethylamino-oxy)norborn-2-ene. 2,2-(Bistrifluoromethylamino-oxy)butane is the sole product from the reaction of but-2-yne.