Treatment of 2-methoxycarbonyl- (or 3-cyano-)allyl acetoacetates with a tertiary amine or triphenylphosphane afforded α-methylene γ-substituted δ-keto esters (or nitrile) in satisfactory yields. Various bases and nucleophiles were tested to elucidate the mechanism. The results of the study strongly suggest an intermolecular pathway involving a SN2′-decarboxylation-SN2′ cascade.
用叔胺或
三苯基膦处理 2-甲氧基羰基-(或 3-
氰基-)
烯丙基乙酰乙酸酯,以令人满意的产率得到 α-亚甲基 γ-取代的 δ-
酮酯(或腈)。测试了各种碱和亲核试剂以阐明其机制。该研究的结果强烈表明涉及 SN2'-脱羧-SN2'级联的分子间途径。