Diastereoselective spiroannulation of phenolic substrates: advances towards the asymmetric formation of the manumycin m-C7N core skeleton

Molecules. 2007 Sep 25;12(9):2215-22. doi: 10.3390/12092215.

Abstract

The asymmetric syntheses of two new spirolactones prepared in optically pure form from L-3-nitrotyrosine are described. The key step, an oxidative spiroannulation, was carried out on the optically active phenols 11a and 11b and afforded the new spirolactones 5a and 5b in 85% and 83% yields, respectively, as mixtures (3:1 dr) of diastereomers. The major diastereomers from these mixtures could be isolated in optically pure form by trituration using acetone-hexanes as the solvent. Thus, the optically active spirolactones (+)-5a (+ 92.8 degrees, c=0.125 acetone) and (+)-5b (+112.0 degrees, c= 0.125 acetone) were obtained after four synthetic steps from L-3-nitrotyrosine in 41% and 43% yield, respectively.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Models, Chemical*
  • Phenols / chemistry*
  • Polyenes / chemical synthesis*
  • Polyenes / chemistry*
  • Polyunsaturated Alkamides / chemical synthesis*
  • Polyunsaturated Alkamides / chemistry*
  • Stereoisomerism

Substances

  • Phenols
  • Polyenes
  • Polyunsaturated Alkamides
  • manumycin