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在I,II和IV报中,曾报道了乙烯型烯基溴化镁分别与亚烃基丙二酸二乙酯、亚烃基乙酰乙酸乙酯及乙烯四羧酸四乙酯的共轭加成反应.本文报道乙烯型烯基溴化镁与亚烃基丙二酸亚异丙酯(1)的加成反应.1由丙二酸亚异丙酯(2)与醛或酮进行Knoevenagel反应制得.2又称为Meldrum’s acid,即2,2-二甲基-1,3-二氧杂环己二酮-[4,6],是一种酸性较强(pK_a=4.83),易于制备,具有稳定环状结构的酯.由于其亚甲基很活泼,具有多种反应性能,因此,近年来在有机合成上引起人们较大的兴趣. 以过量乙烯型烯基溴化镁,在催化量无水CuCl存在下陷,与1进行共轭加成反应,可制得一系列新化合物——β,γ-不饱和仲烃基(或叔烃基)丙二酸亚异丙酯(3).反应式如下:
In reports I, II and IV, the conjugate addition reaction of vinyl-type alkenylmagnesiumbromide with diethyl hydrocarbylmalonate, ethylidene acetoacetate and tetraethyl ethylenetetracarboxylate, respectively, has been reported This paper reports the addition reaction of ethylenyl magnesium bromide with alkylidene malonate (1) .1 It is prepared by Knoevenagel reaction of allylidene malonate (2) with aldehyde or ketone. 2, also known as Meldrum’s acid, 2,2-dimethyl-1,3-dioxacyclohexanedione- [4,6], is a more acidic (pK_a = 4.83) Since its methylene is very active and has a variety of reactivity, it has attracted a great deal of interest in organic synthesis in recent years. With an excess of vinyl-type alkenyl magnesium bromide, A series of new compounds, β, γ-unsaturated secondary (or tertiary alkyl) malonic acid isopropylidene (3) can be obtained by the conjugate addition reaction of CuCl with CuCl in water. :