Rod-like Molecules and Phenol Formaldehyde Oligomers

Isoaromatization of rods containing cyclohexyl residues led to the preparation of phenol/formaldehyde oligomers, such as examples 34 and 35, thus illustrating the possibilities of preparing designer phenol/formaldehyde oligomers for modulating the properties of such resins. 

In our hands, the regioselectivity was usually high, but it could become variable without careful attention to the conditions. Catalysts and rates of addition of enones influenced product distributions. Regioselectivity, though, was dictated mainly by the relative bulk of the participating amine, with primary and secondary amines mainly affording 2- and 4-substituted anilines, respectively. 

With derivatives of benzaldehyde, the reaction proceeded regardless of electron-donating or electron-withdrawing properties of the substituents. A diverse range of aldehydes was employed, extending to heterocyclic compounds such as furfural and aryl dialdehydes. Benzene-1,3-dicarboxaldehyde, with cyclohexenone and benzylamine, reacted to produce a bis-anilino derivative, 2,2 -[l,3-phenylenebis(methylene)bis(A-benzylaniline)]. The yield (65%) was 

This multicomponent reaction was used to construct much larger ligand structures, including scorpion ligands,and recent advances extend to the preparation of ligand structures from seven components in a single step  

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