Use of 1, 3-Dioxin-4-ones and Related Compounds in Sythesis. XXXVIII. Use of 1, 3-Dioxin-4-ones Having a Fluorine or Trifluoromethyl Group at the 5-Position as π2 Components in [2+2]-Photocycloaddition and Diels-Alder Reactions

1, 3-Dioxin-4-ones having fluorine or a trifluoromethyl group at the 5-position were used as the π2 components in Diels-Alder reactions with 1-oxygenated dienes. Use of high-perssure conditions was the essential requisite. While the 5-flurodioxinones were photolabile, the corresponding trifluoromethyl derivatives participated as the enone components in [2+2]photocycloaddition to alkenes, Ring-opening reactions of these adducts by acetal bond cleavage gave cyclobutanes and cyclohexanes. Diels-Alder reactions of the fluorinated homochiral dioxinones having l-menthone at the acetal position with Danishefsky diene proceeded in a completely diastereoselective manner to give single adducts.