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Post pubs.acs.org/JACSTerms of UseEnantioselective Cycloaddition of Munchnones onto [60]Fullerene: Organocatalysis versus Metal CatalysisJuan Marco-Mart ez,Silvia Reboredo,Marta Izquierdo,Vanesa Marcos,Juan Luis Lopez,Salvatore Filippone,and Nazario Mart *,Departamento de Qu ica Organica I, Facultad de Qu ica, Universidad Complutense, E-28040 Madrid, Spain IMDEA-Nanoscience, Campus de Cantoblanco, E-28049 Madrid, SpainS * Supporting InformationABSTRACT: Novel chiral catalytic systems primarily based on each organic compounds and metal salts happen to be developed for the enantioselective [3 + 2] cycloaddition of munchnones onto fullerenes and olefins. These two various approaches proved to be effective and complementary in the synthesis of optically active pyrrolino[3,four:1,2] [60]fullerenes with high levels of enantiomeric excess and moderate to fantastic conversions. Additional functionalization of the pyrrolinofullerene carboxylic acid derivatives has been carried out by esterification and amidation reactions.INTRODUCTION Chirality in fullerenes and connected carbon nanostructures is presently a difficult subject of interest for the style and application of those new optically active compounds in fields for example medicinal chemistry or materials science.Diethyl Purity & Documentation 1 Especially, inside the latter field, where fullerenes discover essentially the most promising applications, chirality has not too long ago proved to play a crucial role inside the manage of some physical properties.Clomazone Protocol two Alternatively, the unavailability of asymmetric synthesis in fullerene science has strongly restricted the use of chiral fullerene derivatives and, therefore, the improvement of chiral carbon nanostructures with enhanced properties.PMID:25027343 A significant breakthrough has been the introduction of asymmetric metal-catalyzed processes to prepare optically pure [60] and [70]fullerene derivatives by cycloaddition reaction of azomethine ylides onto hollow fullerenes3,4 as well as onto metallofullerenes5 using a complete manage of the stereochemical outcome. Additionally, additional not too long ago, organocatalytic solutions happen to be applied for the initial time in fullerene science affording chiral [60]fullerene derivatives by a convergent cycloaddition of allenoates onto C60.six Regardless of the aforementioned achievements, the hard activation and the a lot more hard asymmetric induction of all-carbon cages make the introduction of chirality onto fullerenes nevertheless a challenging and profitable task. Certainly, the absence of functional groups as well as the no coordinating polyolefin nature of fullerenes stop each the use of metal mediated processes plus the employ of chiral organic molecules to activate the fullerene double bonds. Alternatively, what exactly is a drawback inside the chiral functionalization of fullerenes turns into a very helpful setting for the evaluation “a priori” from the employed catalyst, irrespective of the olefin program utilised. Thus, the efficiency, the sense on the asymmetric induction, or, normally, the stereochemical outcome for a chiral metal- or organocatalyst may be benchmarked2014 American Chemical Societyby fullerenes thanks to their neutral behavior toward the catalyst in nucleophilic addition reactions. An illustrative example of this use of fullerenes has lately been reported by our group.3b Hence, inside the search for new optically active fullerene derivatives at the same time as for new chiral induction modes onto no activated double bonds for instance those of fu.
