Tandem Double-Intramolecular [4+2]/[3+2] Cycloadditions of Nitroalkenes. Studies toward a Total Synthesis of Daphnilactone B: Piperidine Ring Construction
作者:Scott E. Denmark、Ramil Y. Baiazitov
DOI:10.1021/jo052001l
日期:2006.1.1
Two model studies in support of a total synthesis of the complex polycyclic alkaloid daphnilactone B have been completed. The objectives of the models studies were to demonstrate the use of a tandem double-intramolecular [4+2]/[3+2] nitroalkene cycloaddition for the stereocontrolled construction of four of the rings in the core of the natural product. The first model study established the ability to
已经完成了两个模型研究,以支持复杂多环生物碱萘甲内酯B的全合成。模型研究的目的是证明使用串联双分子内[4 + 2] / [3 + 2]硝基烯烃环加成反应在天然产物核心中四个环的立体控制结构。第一个模型研究建立了通过修饰双极性亲和物和随后的官能团操纵产生与萘甲内酯B的环A相对应的吡咯烷环的能力。第二个模型研究要求在[4 + 2]环加成中修饰亲双烯体,以适应哌啶环(萘乙内酯B的环B)的形成。硝基烯烃26包含作为二烯的二烯的二烯亲和剂在串联环加成中很好地起作用,以77%的收率得到亚硝基缩醛38a。随后的官能团操纵可实现高产量转化为萘乙内酯B的核心。