抄録
Photoreaction of diketene with N-phenylmaleimide (2) and its dimethyl derivative 3 gave rel-(4R, 5S, 6S)- and rel-(4R, 5R, 6R)-2-oxo-1-oxaspiro [3. 3] heptane-5, 6-dicarboximides (4a and 4b) and their dimethyl derivatives 5a and 5b, respectively. Alcoholysis of compounds 4a and 4b with alcoholic hydrogen chloride gave 5-alkoxycarbonyl-4-oxo-N-phenyl-1, 2-pentanedicarboximides 7 and 8, which were transformed to the corresponding 5-alkoxycarbonyl-3-oxoheptanedioates 9 and 10 by further alcoholysis. Compounds 4a and 4b were hydrolyzed with 10% hydrochloric acid to give 3-carboxy-5-oxohexanoic acid (11). Thermolysis of compounds 4a and 4b gave 3-methylenecyclobutane-1, 2-dicarboximide (12).
