title: Metathesis reactions for the synthesis of ring-fused carbazoles.
abstract: [reactions: see text] The metathesis reaction is used as a key step for the synthesis of the indolo[2,3-a]carbazole core of rebeccamycin 13 and the sulfur analog of furostifoline 21. Using the same methodology for the attempted synthesis of furostifoline, we unexpectedly formed tert-butyl-2a-methyl-1,2,2a,10c-tetrahydro-6H-cyclobuta[c]furo[3,2-a]carbazole-6-carboxylate 26 from the unstable diene, tert-butyl 2-(2-isopropenyl-3-furyl)-3-vinyl-1H-indole-1-carboxylate 25, presumably via a spontaneous pi8 electrocyclization reaction.
authors.affiliation: Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, P.O. Wits, 2050 South Africa.
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Pelly
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Parkinson
authors.forename: Willem A L
authors.initials: WA
authors.lastname: van Otterlo
authors.forename: Charles B
authors.initials: CB
authors.lastname: de Koning
mesh_terms: D002227:Carbazoles / Q000138:chemical synthesis*; D003500:Cyclization; D007211:Indoles / Q000138:chemical synthesis; D009682:Magnetic Resonance Spectroscopy
chemical_list: D002227:Carbazoles; D007211:Indoles; C053339:rebeccamycin