Total synthesis of (-)-himgaline.
The first total synthesis of (-)-himgaline and a highly enantioselective synthesis of its congener (-)-GB 13 are described. Decarboxylative aza-Michael reaction of the hexacyclic lactone precursor under acidic conditions, followed by basic workup, yielded (-)-GB 13 in 80% yield. Cyclization of (-)-GB 13 to oxohimgaline under acidic conditions, followed by internally coordinated sodium triacetoxyborohydride reduction, gave (-)-himgaline as the exclusive product.
Shah
Unmesh
U
Schering-Plough Research Institute, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA.
Chackalamannil
Samuel
S
Ganguly
Ashit K
AK
Chelliah
Mariappan
M
Kolotuchin
Sergei
S
Buevich
Alexei
A
McPhail
Andrew
A
D001643:Bridged Bicyclo Compounds / Q000138:chemical synthesis; D018360:Crystallography, X-Ray; D006571:Heterocyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D024301:Plant Bark / Q000737:chemistry; D014197:Trees / Q000737:chemistry
D001643:Bridged Bicyclo Compounds; C518378:Galbulimima alkaloid 13; D006571:Heterocyclic Compounds; C518376:himgaline