Corrole and nucleophilic aromatic substitution are not incompatible: a novel route to 2,3-difunctionalized copper corrolates

Abstract

The insertion of a –NO2 group onto the corrole framework represents a key step for subsequent synthetic manipulation of the macrocycle based on the chemical versatility of such a functionality. Here we report results on the investigation of a copper 3-NO2-triarylcorrolate in nucleophilic aromatic substitution reactions with “active” methylene carbanions, namely diethyl malonate and diethyl 2-chloromalonate. Although similar reactions on nitroporphyrins afford chlorin derivatives, nucleophilic attack on carbon-2 of corrole produces 2,3-difunctionalized Cu corrolates in acceptable yields (ca. 30%), evidencing once again the erratic chemistry of this contracted porphyrinoid.

Strategies for Corrole Functionalization

“…Paolesse and Smith groups found that corroles participate in S N Ar reactions at free β-positions of the macrocycle if appropriate β-substituents are attached to nearest positions . The NO 2 group is a very useful substituent in organic synthesis and it has been widely used in the functionalization of porphyrins .…”

“…Paolesse and Smith groups found that corroles participate in S N Ar reactions at free β-positions of the macrocycle if appropriate β-substituents are attached to nearest positions. 327 The NO 2 group is a very useful substituent in organic synthesis and it has been widely used in the functionalization of porphyrins. 284 While it is well documented that β-nitroporphyrins can undergo nucleophilic addition and substitution reactions, only a few publications can be found on the functionalization of β-nitrocorroles, especially by S N Ar procedures.…”

“…Paolesse and Smith groups, 327 following the S N Ar method, were able to obtain the interesting 2,3-difunctionalized corrole derivatives 178 and 179 (Figure 50). 327 These compounds were obtained in acceptable yields (ca.…”

Introduction of Carbon Substituents into Nitroarenes via Nucleophilic Substitution of Hydrogen: New Developments

“…However, they can react with nitrocorrole derivatives to afford VNS and ONSH reactions in the nitropyrrolic fragments. 54 As discussed above, chloro(nitroaryl)acetates produced in the VNS reaction of alkyl dichloroacetates upon hydrolysis and decarboxylation give (chloromethyl)nitroarenes. On the other hand, one-pot VNS reaction of alkyl dichloroacetate with nitroarenes and subsequent reaction with Michael acceptors results in the formation of alkyl (nitroaryl)cyclopropanecarboxylates (Scheme 21).…”

Nucleophilic Aromatic Substitution (SNAr) and Related Reactions of Porphyrinoids: Mechanistic and Regiochemical Aspects

“…The electrophilicity of the C 2 ‐position has also been examined with C‐based active methylene nucleophiles. [ 227 ] Treatment of 162 with diethyl malonate and NaOH yielded the diester appended corrole 166 in 34 %. Reaction of 162 with diethyl chloromalonate gave a mixture of compounds, but only yielded 166 in 28 %.…”