e (45)(19% yield), respectively. The reaction of (5) with (43) was also induced thermally to give ethyl 4-acetoxy-3-(acetoxymethyl)coronate (46)(24% yield) in addition to (45)(20% yield). Photocycloaddition of diethyl mesoxalate (21) with (6) gave diethyl 3-oxo-2,4,6-trioxabicyclo[3.2.0]heptane-7,7-dicarboxylate (22)(23% yield). On the other hand, the reactions of 1,3-dimethoxy-(8) and 1,3-bis(ben
用高压
汞灯照射1,3-
二乙酰氧基丙-2-酮(5)和1,3-二氧杂-2-酮(6)的苯溶液得到光环加成产物(7-乙酰氧基甲基-3-氧代2,4,6-三氧杂双环[3.2.0]
庚烷-7-基)-
乙酸甲酯(7)(55%收率)。(5)与(Z)-
乙烯基二
乙酸乙烯酯(23),与(Z)-2-(苄氧基)
乙酸乙烯酯(25),2,3-二氢-
1,4-二恶英(27)和
乙酸乙烯酯(28),
乙酸异丙烯酯(29),乙氧基
乙烯(30)和
1,1-二乙氧基乙烯(43)得到顺式-4,4-双(乙酰氧基甲基)氧杂
环丁烷-2,3-二
乙酸二
乙酸酯(31 )(46%的收率)和反式-异构体(32)(49%产率); 2,2-双(乙酰氧基甲基)-4-(苄氧基)-氧杂-3-
乙酸乙酸酯(33)(由两种异构体组成;产率分别为11%和26%)和4,4-双-(乙酰氧基甲基)-3 -(苄氧基)氧杂-2-烷基
乙酸酯(38)(由两种异构体组成;产率为11%和9%);(8-乙酰氧基甲基-2