Unprecedented Cyanation and Cyanomethylation Following Ring Closure versus Dimer Formation during Anodic Oxidation of the Aspidofractinine Alkaloid Kopsamine
作者:Toh-Seok Kam、Tuck-Meng Lim、Guan-Huat Tan
DOI:10.3987/com-98-8400
日期:——
Anodic oxidation of the aspidofractinine-type indole alkaloid kopsamine on platinum in Et4NClO4/MeCN results in an unprecedented cyanation-cynomethylation reaction following ring closure while oxidation on vitreous carbon in LiClO4-MeOH yielded a dimerization product with a C-2 element of symmetry.
Electrochemical oxidation of aspidofractinine-type indole alkaloids. A facile, electrochemically-mediated conversion of kopsingine to kopsidines A, B, C, and kopsinganol
作者:Guan-Huat Tan、Tuck-Meng Lim、Toh-Seok Kam
DOI:10.1016/0040-4039(94)02468-q
日期:1995.2
Kopsidine A, B, C and kopsinganol,were synthesised from kopsingine in good yields via the stable imminium salt obtained from electrochemical oxidation of kopsingine. Electrooxidation of dihydrokopsingine on the other hand gave the 17-to-5 and 17-to-3 oxo-bridged alkaloids directly, while 3-oxokopsingine was inert to electrooxidation in the potential range employed.