Fullerene diazirine

Thermal extrusion of N2 from O-benzyl- and O-pivaloyl-protected diazirine yields the corresponding carbenes, which react with in toluene to give the fullerene sugars 333 (Scheme 4.67) [377, 378]. These [2+1] carbene additions cleanly lead to 1,2-methano-bridged sugar monoadducts. 

Two examples of the applicability of anomeric carbenes were reported by VaseUa et al. [167,168]. The first demonstrated the utility of olefinic substrates such as Al-phenylmaleimide, acrylonitrile and dimethylmaleate for the formation of glycosidic cyclopropanes. The carbene precursor in this example was the glucose-derived diazirine. As shown in Scheme 7.55, the use of dimethylmaleate produced a mixture of diastereomers with a combined yield of 72%. Although not presented as a schematic, the second and more dramatic example was used to functionalize fullerenes. 

Trifluoromethyl derivatives of diazirines have been largely used as precursors of carbenes, as an example for indole derivatives, 8 for the functionalization of C60 fullerene and for photochemical labeling of biological molecules. 

Glycosylidene diazirines react with electrophilic alkenes, e.g. A-phenylmaleimide, acrylonitrile, dimethyl fumarate, dimethyl maleate, and Cgo-fullerene, to yield spirocyclopropanes with formation of two C-C bonds at the anomeric center [34-37]. 

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