Total synthesis of (+/-)-herbindole B and (+/-)-cis-trikentrin B.
[reaction: see text] Herbindole B and cis-trikentrin B are naturally occurring indoles having the unusual and synthetically challenging pattern of carbon substitution at the 4-7 and 5-7 positions, respectively, with no substitution at the 1-3 positions. The total syntheses of these polyalkylated indoles have been achieved in 19 and 12 steps, respectively. The synthesis of herbindole B relies on two iterations of a quinine monoimine Diels-Alder reaction, while cis-trikentrin B uses a single cycloaddition of a suitable quinone monoimine. Indolization of the adducts provides suitably substituted benzopyrrole nuclei for elaboration to the natural products.
Jackson
Stephen K
SK
Department of Chemistry, University of Western Ontario, London, Ontario, Canada N6A 5B7.
Banfield
Scott C
SC
Kerr
Michael A
MA
D000818:Animals; D047089:Axinella / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D007202:Indicators and Reagents; D026121:Indole Alkaloids / Q000138:chemical synthesis*; D015394:Molecular Structure; D013237:Stereoisomerism
D007202:Indicators and Reagents; D026121:Indole Alkaloids; C506842:herbindole B; C506843:trikentrin B