SEARCH

SEARCH BY CITATION

Keywords:

  • Natural products;
  • Phytochemistry;
  • Polyphenols;
  • Flavanoids;
  • C-C cou­pling

Abstract

The tetrabenzylated catechin 9 was prepared by benzylation of the commercially available pure (+)-catechin (3) and coupled with the commercially unavailable pentabenzylated(–)-gallocatechin 10, prepared in a one-step Mitsunobu-type cyclization of the triol 8. The highly stereoselective synthesis of benzylated prodelphinidins – catechin-(4α[RIGHTWARDS ARROW]8)-gallocatechin (13), gallocatechin-(4α[RIGHTWARDS ARROW]8)-gallocatechin (14), and gallocatechin-(4α[RIGHTWARDS ARROW]8)-catechin (15) – is reported for the first time. The ESI(+)-CID mass spectra of the coupling products were found to feature regioselective retro-Diels–Alder (RDA) reactions and unusual sequential losses of pairs of C7H7· radicals (182 u) from the Na+ adduct ions.