The First Total Synthesis of (+)-Bullatacin, a Potent Antitumor Annonaceous Acetogenin, and (+)-(15,24)-bis-epi-Bullatacin
作者:Hiroyuki Naito、Eiji Kawahara、Katsunori Maruta、Minoru Maeda、Shigeki Sasaki
DOI:10.1021/jo00119a019
日期:1995.7
This paper reports the first total synthesis of the natural product (+)-bullatacin (1), a representative of potent antitumor Annonaceous acetogenins, as well as a stereoisomer (+)-(15,24)-bisepi-bullatacin (2). In this synthesis, a new, efficient method has been developed to introduce the gamma-lactone into the bistetrahydrofuran skeleton through in situ alkylation of epoxide 4 by the alpha-sulfonyl carbanion of phenyl sulfone 5. The methylated gamma-lactone was successfully synthesized by a sequence of reactions comprising an aldol reaction, an acidic lactonization, and elimination under mild, basic condition.