| In a synthetic study of a new carbonyl enophile, the ene reactions of dimethyl dioxosuccinate (81) with olefins were investigated and it was found the 81 reacts smoothly with most of the olefins investigated under thermal conditions to give the expected products in good yields. Sequential ene reactions to form cyclic products were also investigated and it was found that under catalysis with tin tetrachloride, the ene reaction product from methylenecyclohexane (8) and 81, dimethyl 2-oxo-3-hydroxyl-3-(1;The mechanism of ene reactions of a selected group of carbonyl enophiles with 8 and 1-methylenetetralin (129) were studied by measurement of inter- and intramolecular hydrogen-deuterium isotope effects. In the thermal ene reactions of both 81 and diethyl oxomalonate (3) with 8, both inter- and intramolecular isotope effects are primary and substantial, consistent with concerted mechanisms. In the tin tetrachloride catalyzed reaction of 3 with 8, and in the reaction of acetylium hexachloroantimonate (CH... |
