Synthesis of anti and syn hydroxy-iso-evoninic acids†
Sarah A. Warren,Stephen Stokes,Christopher S. Frampton,Andrew J. P. White,Alan C. Spivey
Organic & Biomolecular Chemistry Pub Date : 05/10/2012 00:00:00 , DOI:10.1039/C2OB25625H
Abstract

The first synthesis of hydroxy-iso-evoninic acid (2), a pyridyl diacid found as a macrodilactone bridging ligand in bioactive Celastraceae sesquiterpenoid-based natural products, has been achieved in 9 steps and an overall yield of 26%. The synthesis utilizes a benzilic ester rearrangement (BER) and a late stage benzylic oxidation to give access to all four stereoisomers whose absolute stereochemistry was assigned following chromatographic separation and anomalous dispersion X-ray crystallography.

Graphical abstract: Synthesis of anti and syn hydroxy-iso-evoninic acids