A divergent approach for the total syntheses of cernuane-type and quinolizidine-type Lycopodium alkaloids
作者:Yasuhiro Nishikawa、Mariko Kitajima、Noriyuki Kogure、Hiromitsu Takayama
DOI:10.1016/j.tet.2008.12.067
日期:2009.2
syntheses of cernuane-type and quinolizidine-type Lycopodium alkaloids are described. A common intermediate 5 for the two types of alkaloids was assembled practically from (+)-citronellal via organocatalytic α-amination, followed by the construction of oxazolidinone that was used for diastereoselective allylation. Key compound 5 was converted into cermizine C (3), and this in turn was converted into senepodine
描述了天南星型和喹oli嗪型Lycopodium生物碱的不同总合成。两种生物碱的通用中间体5实际上是通过有机催化α-胺化反应从(+)香茅醛中组装而成的,然后构建了用于非对映选择性烯丙基化的恶唑烷酮。关键化合物5被转化为cermizine C(3),然后通过区域选择性Polonovsky-Potier反应又被转化为senepodine G(4)。代表性的鹿角烷型生物碱(-)-鹿氨酸(1)以及(+)-cermizine D(2)的总合成也由5完成 通过利用不对称转移氨基烯丙基化作为关键步骤。