1,3-Dipolar cycloaddition of several azomethine ylides to [60]fullerene: synthesis of derivatives of 2′,5′-dihydro-1′H-pyrrolo[3′,4′:1,2][60]fullerene1

Abstract

Imines 1 have been prepared by the condensation of benzaldehyde and corresponding primary amines in which the ester group, phosphonate ester group and depsipeptide are introduced. [60]Fullerene reacts with imines 1 to give the corresponding isomers of fullerene-fused proline derivatives 2 via a process of 1,3-dipolar cycloaddition. 1,3,5-Tris(ethoxycarbonylmethyl)perhydro-1,3,5-triazine 4, which has been prepared by the condensation of ethyl glycinate with paraformaldehyde, depolymerizes thermally to provide an azomethine ylide which reacts with [60]fullerene to afford ethyl 2′,5′-dihydro-1′H-pyrrolo[3′,4′∶1,2][60]fullerene-2′-carboxylate 5. 2-Phenyl-4,5-dihydrooxazol-5-one 6 tautomerizes thermally to form the mesoionic oxazolium 5-oxide 6a, which then, as a cyclic azomethine ylide, combines further with [60]fullerene to give 5′-phenyl-2′H-pyrrolo[3′,4′∶1,2][60]fullerene 7 which possesses C_s symmetry.