Enantioselective Approach to Securinega Alkaloids. Total Synthesis of Securinine and (−)-Norsecurinine
作者:David González-Gálvez、Elena García-García、Ramon Alibés、Pau Bayón、Pedro de March、Marta Figueredo、Josep Font
DOI:10.1021/jo901059n
日期:2009.8.21
The most representative securinega alkaloids have been synthesized through a new strategy involving the palladium-catalyzed enantioselective allylation of a cyclic imide, a vinylogous Mannich reaction, and a ring-closing metathesis process, as the key steps. The diastereoselectivity of the vinylogous Mannich reaction was in partial agreement with DFT theoretical calculations performed in a model system
作为关键步骤,通过一种新策略合成了最具代表性的securinega生物碱,该策略涉及钯催化的环状酰亚胺的对映选择性烯丙基化,乙烯基曼尼希反应和闭环复分解过程。乙烯基曼尼希反应的非对映选择性与在模型系统中进行的DFT理论计算部分吻合。(-)-正氨基苏氨酸的合成距离琥珀酰亚胺仅9步,总产率为14%,而芥子碱的合成距离戊二酰亚胺仅10步,总产率为20%。两种合成均与先前所述的合成有利地比较。这三个关键的转化已经以合成有用的规模(大于500 mg)进行了。此外,由于对映选择性是由手性膦配体引起的,