Ferf-Amyl group

A flexible means of access to functionalized supports for solid-phase synthesis is based on metallated, cross-linked polystyrene, which reacts smoothly with a wide range of electrophiles. Cross-linked polystyrene can be lithiated directly by treatment with n-butyllithium and TMEDA in cyclohexane at 60-70 °C [1-3] to yield a product containing mainly meta- and para-Iithiated phenyl groups [4], Metallation of noncross-linked polystyrene with potassium ferf-amylate/3-(lithiomethyl)heptane has also been reported [5], The latter type of base can, unlike butyllithium/TMEDA [6], also lead to benzylic metallation [7]. The C-Iithiation of more acidic arenes or heteroar-enes, such as imidazoles [8], thiophenes [9], and furans [9], has also been performed on insoluble supports (Figure 4.1). These reactions proceed, like those in solution, with high regioselectivity. 

Activities lower than those of pyrocatechol were found with all the observed substances of Type la, where R- = ferf-alkyl group (a) 1,1-dimethylethyl (denoted further as tert-butyl), (b) 1,1-dimethylpropyl (tert-amyl), (c) 1,1,3,3-tetramethylbutyl (tert-octyl), and (d) 1,1,3,3,5,5-hexamethylhexyl (tert-dodecy ) the relative activities (calculated from... 

All tertiary alkyl groups (a-d) are branched in the same way on the a-carbon atom and differ in the length of the carbon chain and the nature of further branching the activity first decreases until substitution by the alkyl group with three carbon atoms in the main chain (i.e., tert-amyl), then it increases to the ferf-dodecyl group (C6 chain) nevertheless, the... 

The prefix tert is found in ferf-butyl and ferf-pentyl because each of these substituent names describes only one alkyl group. The name ferf-hexyl cannot be used because it describes two different alkyl groups. (In older literature, you might find amyl used instead of pentyl to designate a five-carbon alkyl group.)... 

Similarly [TinOi3(OlV)i8] was converted to [TinOi3(OEt)5(OPr )i3]" and the giant oxo-ferf-butoxide [Tii8028H(OBu )i7] also exchanged the 5 terminal Bu O groups bonded to five-coordinated titanium with tertiary amyl alcohol. These reactions demonstrated the robust nature of the metal-oxo core structure in these compounds. 

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