Corrole bifuran-containing

An alternative route to these bifuran-containing corroles was also pursued it involved carrying out an acid-catalyzed condensation between the diformyldifuryl sulfide 2.43 and an appropriate diacid dipyrrylmethane species (e.g., 2.35-2.37)... 

A more direct, 2 + 2 approach to the synthesis of cobalt(III) corroles has been described. It involves condensing a diformyl bipyrrole such as 2.140 with a diacid dipyrrylmethane such as 2.36. This approach is thus similar to the one used to obtain the bifuran-containing corroles 2.3 2.40 described earlier. In the present instance, the diacid bipyrrole 2,141 may also be reacted with a diformyl dipyrrylmethane such as 2.142. This affords corrole 2.125b (Scheme 2.1.37). In either case, the reaction must be carried out in the presence of Co(II) and PPhs. This requirement for a presumably coordinating metal cation is in stark contrast to what is seen in the case of the bifuran analog there, no metal is needed to template the reaction. ... 

Only very few examples of experiments devoted to the alkylation of heterocorroles have appeared in the literature. These have involved allwlation of the bifuran-containing corrole 2.39 with methyl iodide or ethyl iodide. For instance, the mono-A-methyl corrole 2.241 was prepared in this way from corrole 2.39 in 56% yield (Scheme 2.1.88). In an analogous manner, the mono-A-ethyl corrole 2.242 was prepared in 45% yield starting from 2.39. In both cases, the mono-A-alkyl corroles were isolated as their hydroiodide salts. In fact, these corroles were found to be so basic that they could not be isolated in their free-base forms. ... 

The bifuran-containing corrole 2.39 was also subject to acylating conditions. In this instance, treatment of corrole 2.39 with acetyl chloride using aluminum trichloride as the Lewis acid afforded the C(5)-acetyl-substituted corrole derivative 2.245 in 31% yield (Scheme 2.1.89). In addition to this product, a di-substituted corrole was also obtained. This was presumed to be either a 2,18- or a 3,17-diacetyl-substituted corrole. However, no evidence was put forward in support of either of these assignments. 

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