Department of Chemistry and Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
Org Lett. 2012 Apr 20;14(8):2078-81. doi: 10.1021/ol300599p. Epub 2012 Apr 5.
Divergent total syntheses of (+)-spegazzinine (1) and (-)-aspidospermine (2) and their extensions to the synthesis of C19-epi-aspidospermine and C3-epi-spegazzinine are detailed, confirming the relative stereochemistry and establishing the absolute configuration of (+)-spegazzinine. A powerful intramolecular [4 + 2]/[3 + 2] cycloaddition cascade of a 1,3,4-oxadiazole provided the pentacyclic skeleton and all the requisite stereochemistry of the natural products in a single reaction that forms three rings, four C-C bonds, and five stereocenters.
详细描述了 (+)-spegazzinine（1）和（-）-aspidospermine（2）的发散全合成及其对 C19-epi-aspidospermine 和 C3-epi-spegazzinine 的合成扩展，证实了（+）-spegazzinine 的相对立体化学，并确定了其绝对构型。一个强大的 1,3,4-噁二唑分子内[4 + 2]/[3 + 2]环加成级联反应在单个反应中提供了五元环骨架和天然产物所需的所有立体化学，形成了三个环、四个 C-C 键和五个立体中心。
