Diversity Driven Decoration and Ligation of Fullerene by Ugi and Passerini Multicomponent Reactions

Aiming at providing an efficient and versatile method for the diversity‐oriented decoration and ligation of fullerenes, we report the first C60 derivatization strategy based on isocyanide‐multicomponent reactions (I‐MCRs). The approach comprises the use of Passerini and Ugi reactions for assembling pseudo‐peptidic scaffolds (i.e., N‐alkylated and depsipeptides, peptoids) on carboxylic acid‐functionalized fullerenes. The method showed wide substrate scope for the oxo and isocyanide components, albeit the Ugi reaction proved efficient only for aromatic amines. The approach was successfully employed for the ligation of oligopeptides and polyethyleneglycol chains (PEG) to C60, as well as for the construction of bis‐antennary as well as PEG‐tethered dimeric fullerenes. The quantum yields for the formation of 1O2 was remarkable for the selected compounds analyzed. Supplying the MCR power plant: A new protocol enables the diversity‐driven decoration of fullerenes via isocyanide‐based multicomponent reactions (Ugi‐four component, U‐4CR, and Passerini‐three component, P‐3CR, reaction) giving products with excellent yields and a high atom economy. Evaluation of highly diversified fullerenes as photosensitizers showed promising results, demonstrating possible applications in photodynamic therapies.