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, the authors 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 pi(8) electrocyclization reaction.
Reference:
Pelly, SC, et al. 2005. Metathesis reactions for the synthesis of ring-fused carbazoles. Journal of Organic Chemistry, vol. 70(25), pp 10474-10481
Pelly, S., Parkinson, C., Van Otterlo, W., & De Koning, C. (2005). Metathesis reactions for the synthesis of ring-fused carbazoles. http://hdl.handle.net/10204/2040
Pelly, SC, CJ Parkinson, WAL Van Otterlo, and CB De Koning "Metathesis reactions for the synthesis of ring-fused carbazoles." (2005) http://hdl.handle.net/10204/2040
Pelly S, Parkinson C, Van Otterlo W, De Koning C. Metathesis reactions for the synthesis of ring-fused carbazoles. 2005; http://hdl.handle.net/10204/2040.
