4-acetyl-3-thienyl butyl

Butyl 3-thienyl tellurium was lithiated exclusively in the 5-position of the thiophene ring upon treatment with lithium diisopropylamide. The lithiated compound reacted with dimethylacetamide to produce 5-acetyl-3-thienyl butyl tellurium1. 

Also as noted above any substituents present have little effect upon such oxidations. In 2,2 -methylenedifuran (118) the rings are attacked simultaneously giving a tetramethoxy derivative.297 Even the bulk of the fert-butyl group has little effect.298 The only marked substituent effect is that exerted by an aromatic (benzene, thiophene, furan) residue which, if directly attached at the 2-position, promotes elimination instead of the addition of another methoxy group. The net process then becomes one of arylation, as when 2-(2-thienyl)furan (119) is oxidized to 120.298 There are reports that acetyl and carboxy groups can be ejected during oxidation, but that ester groups are usually retained.287... 

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