Cleavage of the 1,6-anhydro bridge in the levoglucosenone adduct with isoprene and its derivatives

Methods of opening of the 1,6-anhydro bridge in levoglucosenone (ZnCl(2)-Ac(2)O), its adducts with isoprene (ZnCl(2)-Ac(2)O, HCl-MeOH), and hydroxy derivatives (H(3)PO(4)-Ac(2) (O)) were studied. Cleavage of the 1,6-anhydro bridge in anomeric acetoxy derivatives of levoglucosenone-isoprene adduct by the action of BF(3) center dot Et(2)O-Ac(2)O was accompanied by acetylation at the allylic C (6) position.