James P Lajiness1, Wanlong Jiang, Dale L Boger. 1. Department of Chemistry and Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
Abstract
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.
Divergent total syntheses of (+)-spegazzinine (1) and n class="Chemical">(-)-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.
Authors: Gregory I Elliott; Juraj Velcicky; Hayato Ishikawa; Yongkai Li; Dale L Boger Journal: Angew Chem Int Ed Engl Date: 2006-01-16 Impact factor: 15.336