A new practical route for the first total synthesis of (+)-homopumiliotoxin 223G is described, in which the palladium-catalyzedcarbonylation of the vinyl iodide, leading to efficient construction of the quinolizidine nucleus incorporating the (Z)-alkylidene side chain, is the key strategic element. Another key feature of this synthesis involves the Lewis acid-induced chelation-controlled propargylation
Determination of Absolute Stereochemistry and an Alternative Synthesis of Homopumiliotoxin 223G: Identification on Chiral GC Columns with the Natural Alkaloid
作者:Chihiro Kibayashi、Sakae Aoyagi、Tzu-Chueh Wang、Kosuke Saito、John W. Daly、Thomas F. Spande
DOI:10.1021/np990641b
日期:2000.8.1
The same sequence using (+/-)-4 was applied to the synthesis of racemic 223G. Gas chromatography of a sample of racemic 223G showed no separation into enantiomers on four different cyclodextrin-based chiral GC columns. We found, however, that the O-acetates of (+/-)-223G gave a nearly baseline separation on either a beta-cyclodextrin column or a permethylated beta-cyclodextrin column. The O-acetate of