1,2-Asymmetric Induction in Diastereoselective Zwitterionic Aza-Claisen Rearrangements: Key Steps in Optically Active Alkaloid Synthesis
作者:Carolin Heescher、Dieter Schollmeyer、Udo Nubbemeyer
DOI:10.1002/ejoc.201300389
日期:2013.7
proceeds with complete simple diastereoselectivity (internal asymmetric induction) and complete 1,2-asymmetric induction to generate a new C–C bond adjacent to a chiral C-N-Boc functionality. The resulting γ,δ-unsaturated amides were cyclised to give the corresponding pyrrolizidinones, which enabled the determination of the relative configuration of the stereotriads. Vinyl group degradation and a final
光学活性 N-烯丙基吡咯烷和 α-苯氧基乙酰氟的两性离子 aza-Claisen 重排以完全简单的非对映选择性(内部不对称诱导)和完全 1,2-不对称诱导进行,以产生与手性 CN-Boc 相邻的新 C-C 键功能。所得的 γ,δ-不饱和酰胺被环化得到相应的吡咯里西酮,这能够确定立体三联体的相对构型。乙烯基降解和最终的内酰胺还原得到 (+)-petasinine(一种吡咯里西啶生物碱)的光学活性类似物。此外,含有立体三联体的酰胺应该是光学活性 elaeocarpin(一种吲哚里西啶生物碱)全合成有用的关键中间体。