Destabilizing Predictive Copper‐Catalyzed Click Reactions by Remote Interactions with a Zinc‐Porphyrin Backbone
Résumé
In order to obtain new supramolecular ligands build up around a zinc-porphyrin scaffold, we envisioned to access sulfonyl triazole intermediates by well-known copper-catalyzed click reactions. Unexpectedly, these triazole intermediates do not form due to the presence of the zinc-porphyrin moiety at close proximity of the active copper species. Indeed, the copper catalyst undergoes a different chemo-selective reaction pathway reacting with traces of alcohols or water from the media that behave as effective nucleophiles leading to sulfonyl imidates or sulfonyl amides covalently-connected to the zincporphyrin. We show that copper-catalyzed click reactions can undergo different reaction mechanisms when the catalytic events occur at close proximity of a zinc-porphyrin unit which likely acts as a Lewis acid to stabilize otherwise inaccessible reaction intermediates.
Domaines
Chimie
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