Co2(CO)8-catalyzed intramolecular hetero-Pauson-Khand reaction of alkynecarbodiimide: synthesis of (+/-)-physostigmine.
[reaction: see text] Herein we describe a novel Co(2)(CO)(8)-catalyzed intramolecular aza-Pauson-Khand-type reaction of alkynecarbodiimide derivatives affords pyrrolo[2,3-b]indol-2-one ring systems in reasonable yields. This is the first reported Co(2)(CO)(8) successfully applied in the hetero-Pauson-Khand reaction. Significantly, the transformation of one of our pyrrolo[2,3-b]indol-2-one derivatives into the indole alkaloid, (+/-)-physostigmine, was completed in a highly stereoselective manner.
Mukai
Chisato
C
Division of Pharmaceutical Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Japan. cmukai@kenroku.kanazawa-u.ac.jp
Yoshida
Tatsunori
T
Sorimachi
Mao
M
Odani
Akira
A
D000480:Alkynes / Q000737:chemistry*; D002234:Carbodiimides / Q000737:chemistry*; D002384:Catalysis; D010830:Physostigmine / Q000138:chemical synthesis*
D000480:Alkynes; D002234:Carbodiimides; D010830:Physostigmine