Towards 20,20-difluorinated bryostatin: synthesis and biological evaluation of C17,C27-fragments

Org Biomol Chem. 2019 Feb 6;17(6):1487-1505. doi: 10.1039/c8ob03152e.

Abstract

Bryostatins with modified C17-C27 fragments have not been widely studied. The synthesis of 20,20-difluorinated analogues was therefore investigated. Such substitution would inhibit dehydration involving the C19-hydroxyl group and stabilise the ring-closed hemiacetal tautomers. Following preliminary studies, allyldifluorination was used to prepare difluorinated alkenols. Oxidation followed by stereoselective Wittig reactions of the resulting α,α-difluorinated ketones gave (E)-α,β-unsaturated esters that were taken through to complete syntheses of 2-hydroxytetrahydropyrans corresponding to C17-C27 fragments of 20,20-difluorinated bryostatin. These compounds showed modest binding to protein kinase Cα isozyme. Attempts were also undertaken to synthesise macrocyclic 20,20-difluorinated analogues. During preliminary studies, allyldifluorination was carried out using a 2-alkyl-3-bromo-1,1-difluoropropene.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bryostatins / chemical synthesis*
  • Bryostatins / chemistry*
  • Bryostatins / metabolism
  • Chemistry Techniques, Synthetic
  • Halogenation*
  • Models, Molecular
  • Molecular Conformation
  • Protein Kinase C / metabolism

Substances

  • Bryostatins
  • Protein Kinase C