Stable carbocations. Part IX. Reactions involving sterically crowded ferrocenylalkylium ions
Abstract
The 1-ferrocenyl-1,2,2,3,3-pentamethylbutylium ion (6) is formed when 3-ferrocenyl-2,2,4,4-tetramethylpentan-3-ol (1) is dissolved in trifluoroacetic acid. At 33°, this cation reacts both by fragmentation [to give the 1-ferrocenyl-1,2-dimethylpropylium ion (7)] and by rearrangement [to the 1,2-dimethyl-1-(2-t-butylferrocenyl)propylium ion (10)]. At 65°, the cation (10) rearranges to the 2,2-dimethyl-1-(2-t-butylferrocenyl)propylium ion (14).