General Approach for the Synthesis of 12-Methoxy-Substituted Sarpagine Indole Alkaloids Including (−)-12-Methoxy-<i>N</i><sub>b</sub>-methylvoachalotine, (+)-12-Methoxy-<i>N</i><sub>a</sub>-methylvellosimine, (+)-12-Methoxyaffinisine, and (−)-Fuchsiaefoline
作者:Hao Zhou、Xuebin Liao、Wenyuan Yin、Jun Ma、James M. Cook
DOI:10.1021/jo052081t
日期:2006.1.1
a Schöllkopf-based chiral auxiliary in good yield. This ester was then employed in the first regiospecific, stereospecific total synthesis of (+)-12-methoxy-Na-methylvellosimine, (+)-12-methoxyaffinisine, (−)-fuchsiaefoline, and 12-methoxy-Nb-methylvoachalotine in excellent overall yield. The asymmetric Pictet−Spengler reaction and enolate-driven palladium-catalyzed cross-coupling processes served as
的对映体特异性合成7-甲氧基d -色氨酸乙酯通过用一个基于Schöllkopf-手性辅助良好产率的杂环化拉洛克过程的组合完成。然后将该酯在第一区域专一采用,(+)立体有择的全合成- 12甲氧基Ñ一个-methylvellosimine,(+) - 12-methoxyaffinisine,( - ) - fuchsiaefoline和12甲氧基Ñ b -methylvoachalotine具有极好的总产量。非对称的Pictet-Spengler反应和烯醇盐驱动的钯催化的交叉偶联过程是关键步骤。通过(+)-12-甲氧基-N之间的Tollens反应建立12-甲氧基-N b-甲基voachalotine的C(16)的季中心一个-methylvellosimine和甲醛以形成二醇17。在二醇两个前手性伯醇17是由羟基的氧化环化(DDQ)在轴向位置分化17与在苄基现在的位置是[C(6)],以形成环状醚[C(6)-O