Synthesis of Corannulene and Alkyl Derivatives of Corannulene

Synthesis of corannulene and alkyl corannulene derivatives has been accomplished using solution-phase chemistry. The key step in the synthesis is the coupling of benzylic bromides of 1,6,7,10-tetraalkylfluoranthene derivatives by low-valent titanium to construct the corannulene nucleus. The use of low-valent titanium represents a viable alternative to flash vacuum pyrolysis methods previously developed. Corannulene (1), methylcorannulene (8), three different dimethylcorannulenes (2, 3, 5), two different tetramethylcorannulenes (4, 6), acecorannulylene (7), C5h symmetric pentamethylcorannulene (9), and decamethylcorannulene (10) have been prepared using low-valent titanium carbon−carbon coupling chemistry and halogen for alkyl exchange chemistry mediated by trimethylaluminum and catalytic nickel salts.