Golden opportunities in natural product synthesis: first total synthesis of (-)-isocyclocapitelline and (-)-isochrysotricine by gold-catalyzed allene cycloisomerization.
The first enantioselective total syntheses of the beta-carboline alkaloids (-)-isochrysotricine (1) and (-)-isocyclocapitelline (2) are reported which confirm the absolute configuration of these natural products. Key steps are the copper-mediated S(N)2'-substitution of propargyl oxiranes 13/14 and the gold-catalyzed cycloisomerization of alpha-hydroxyallene 15, resulting in a highly efficient center-to-axis-to-center chirality transfer.
Volz
Frank
F
Organic Chemistry II, University of Dortmund, Otto-Hahn-Strasse 6, D-44221, Dortmund, Germany.
Krause
Norbert
N
D000438:Alcohols / Q000737:chemistry; D000466:Alkadienes / Q000737:chemistry*; D000470:Alkaloids / Q000737:chemistry*; D002243:Carbolines / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D002625:Chemistry, Organic / Q000379:methods*; D006046:Gold / Q000737:chemistry; D008956:Models, Chemical; D015394:Molecular Structure; D013237:Stereoisomerism
D000438:Alcohols; D000466:Alkadienes; D000470:Alkaloids; D002243:Carbolines; C521747:isochrysotricine; C521748:isocyclocapitelline; C025947:propadiene; D006046:Gold