Synthesis of [60]- and [70]Fullerene-Fused Tetrahydroquinoxaline Derivatives by Oxidative [4+2] Cycloaddition with Unusual Reactivity and Regioselectivity

The oxidative [4 + 2] reaction of o-phenylenedi-amine-derived disulfonamides with fullerene C-60 and C-70 is reported, in which electron-deficient reactants showed high reactivity. The reaction of C-70 exhibited unusual regioselectivity, yielding a [5,6]-adduct as the major product, which was characterized by( 1)H, C-13 NMR and single-crystal X-ray diffraction. DFT calculations revealed the reaction is an inverse-electron demand Diels-Alder (IEDDA) reaction, and the [5,6]-adduct of C-70 is a kinetic product.

Automated summary

This study reports the oxidative [4 + 2] reaction of o-phenylenediamine-derived disulfonamides with fullerene C-60 and C-70. The reactants with electron deficiency showed high reactivity. The reaction of C-70 exhibited unusual regioselectivity, yielding a [5,6]-adduct as the major product, which was characterized by experimental and computational methods.