Explorations in organic chemistry leading to the total synthesis of (+/-)-gelsemine.
The total synthesis of (+/-)-gelsemine (1) is described. A defining phase of the effort involved recourse to a strategic oxetane ring (see compound 25). It was constructed anticipating an intramolecular displacement of the carbon (C17)-oxygen (O4) bond (see product 48). A key intermediate in the stereospecific elaboration of the oxetane linkage was enone 22, which was susceptible to two beta-face attacks leading to 24 and, thence, 25. Three sigmatropic rearrangements were employed in building the bridgehead (C20) and the spiroanilide (C7) quaternary centers en route to gelsemine.
Ng
Fay W
FW
Department of Chemistry, Columbia University, Havemeyer Hall, 3000 Broadway, New York, New York 10027, USA.
Lin
Hong
H
Chiu
Pauline
P
Danishefsky
Samuel J
SJ
D000470:Alkaloids / Q000138:chemical synthesis*; D013237:Stereoisomerism
D000470:Alkaloids; C063230:gelsemine