Non-Pyrolytic Syntheses of Buckybowls: Corannulene, Cyclopentacorannulene, and a Semibuckminsterfullerene

Abstract

Corannulene (1), cyclopentacorannulene (2), and a C30H12 semibuckminsterfullerene (3) have been prepared by non-pyrolytic methods employing bromomethyl/dibromomethyl and/or dibromomethyl/dibromomethyl coupling with low-valent titanium or vanadium. Reductive coupling of tetrakis(dibromomethyl)fluoranthene (8) with vanadium(III) chloride and lithium aluminum hydride affords corannulene in 70−75% yield. Similarly, hexakis(dibromomethyl)fluoranthene (13) leads to cyclopentacorannulene in 20−30% yield, and dodecabromo(octamethyl)indenofluoranthene (6) affords semibuckminsterfullerene (3) in 20% yield.