THE USE OF ACYCLIC MONOTERPENES IN THE PREPARATION OF BETA-PYRONES - SYNTHESIS OF THE RIGHT-HAND FRAGMENT OF USNEOIDONE-E

The right hand fragment, 36, of Usneoidone E, 1, a powerful antiviral and antitumoural agent has been synthesized from the beta-pyrone 32. U sing linalool as starting material, a 2,2,6,6-tetrasubstituted dihydro pyrane 20, precursor of 32 and 33, was prepared. 20 was also synthesiz ed From geranyl acetate through selenide 7, and is a versatile precurs or for the synthesis of tetaprenyltoluquinols. Unambiguous C-13 NMR as signment has been done by 2D correlations.