A novel method for the synthesis of the oxime of 4-methyl-2,4,6-cycloheptatrien-1-one (Eschenmoser's oxime) is proposed. The method involves redox enlargement of the ring of 4-dibromomethyl-4-methyl-2,5-cyclohexadien-1-one oxime through the action of Ni(PPh3)4 in DMF (in the presence of Zn). The product is formed as a mixture ofsyn- andanti-forms readily interconverting in solutions. A similar reaction
                                    提出了一种合成 4-methyl-2,4,6-cycloheptatrien-1-one (Eschenmoser's 
肟) 
肟的新方法。该方法包括通过 Ni(PPh3)4 在 
DMF 中(在 Zn 存在下)的作用使 4-二
溴甲基-4-甲基-2,5-环
己二烯-1-酮
肟的环氧化还原扩大。产物形成为在溶液中容易相互转化的合成和反形式的混合物。4-甲基-4-三
氯甲基-2,5-环
己二烯-1-酮
肟的类似反应提供了agem-α-中心的半醌型卡宾(1,2-双-(1-甲基-4-oxyimino-2 ,5-环
己二烯基)-
1,2-二氯乙烯),以及 4-chloro-5-methyl-2,4,6-cycloheptatrien-1-one 
肟的正异构体和反异构体,它们很容易分离,但在解决方案。对于后面的化合物,