Total synthesis of (+)-dihydrocuscohygrine and cuscohygrine.
The first enantioselective synthesis of (+)-dihydrocuscohygrine 1 and cuscohygrine 2 is presented. 1 was obtained in nine steps and 30% overall yield with a ruthenium-catalyzed tandem ring rearrangement metathesis key step starting from enantiomerically pure cycloheptene-1,3,5-triol derivative 6. The unknown absolute configuration of natural dihydrocuscohygrine 1 could be determined as (S,S)-(-). Cuscohygrine 2 was obtained by Jones oxidation of 1 in quantitative yield but unfortunately with complete epimerization.
Stapper
Christian
C
Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 135, D-10623 Berlin, Germany.
Blechert
Siegfried
S
D000096:Acetone / Q000031:analogs & derivatives* / Q000138:chemical synthesis*; D002384:Catalysis; D020650:Combinatorial Chemistry Techniques; D008401:Gas Chromatography-Mass Spectrometry; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010084:Oxidation-Reduction; D011759:Pyrrolidines / Q000138:chemical synthesis*; D012428:Ruthenium / Q000737:chemistry*; D013237:Stereoisomerism
D011759:Pyrrolidines; C472459:dihydrocuscohygrine; D000096:Acetone; D012428:Ruthenium; C098327:cuscohygrine