New 3-cyano-4,5-dihydrofurans and 4-cyano-1,2-dioxan-3-ols were alternatively synthesized in good yields by the oxidation of acylacetonitrile building blocks with manganese(III) acetate in the presence of alkenes without any byproducts. The reaction at reflux temperature gave 3-cyano-4,5-dihydrofurans under an argon atmosphere, while 4-cyano-1,2-dioxan-3-ols were obtained at 23°C under an air atmosphere except for the reaction of styrene with benzoylacetonitrile which afforded 2-cyano-1,4-diphenylbutane-1,4-dione, and the reaction of 1,1,-diphenylethene with 2-(2-cyano-1-oxoethyl)-5-methylfuran which yielded 2-cyano-4,4-diphenylbutanolide without any cyclic peroxides. The oxidation of benzoylacetonitrile itself at 23°C under an air atmosphere in the absence of alkene gave benzoic acid. Easy conversion of the 1,2-dioxanes to furans was demonstrated, and mechanisms for the formation of dihydrofurans and dioxans as well as the unusual transformation to butanedione and butanolide were also discussed.
新型3-
氰基-4,5-二氢
呋喃和4-
氰基-1,2-二氧杂环-3-醇通过在烯烃存在下,用
醋酸锰(III)对酰基
乙腈构建块进行氧化,获得了良好产率且没有副产物。回流温度下的反应在
氩气气氛中生成3-
氰基-4,5-二氢
呋喃,而在空气气氛下23°C下反应则获得4-
氰基-1,2-二氧杂环-3-醇,除了苯甲基
乙腈与
苯乙烯的反应生成了2-
氰基-1,4-二苯基丁-1,4-二酮,以及
1,1-二苯乙烯与2-(2-
氰基-1-氧代乙基)-5-甲基
呋喃的反应生成2-
氰基-4,4-二苯基丁内酯,没有生成任何环状过氧化物。苯甲基
乙腈本身在空气气氛下23°C的氧化反应在缺乏烯烃的情况下产生了
苯甲酸。还展示了1,2-二氧杂环转化为
呋喃的简便过程,同时讨论了二氢
呋喃和二氧杂环的形成机制,以及向
丁二酮和丁内酯的不寻常转化。