On the mechanism of phthalimidine formation via o-phthalaldehyde monoimines. New [1,5]-H sigmatropic rearrangements in molecules with the 5-aza-2,4-pentadienal
On the mechanism of phthalimidine formation via o-phthalaldehyde monoimines. New [1,5]-H sigmatropic rearrangements in molecules with the 5-aza-2,4-pentadienal
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DOI：
10.1021/jo0508494
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发表时间：
2005-09-16
影响因子：
3.6
通讯作者：
Alvarez, A
中科院分区：
文献类型：
--
作者：
Alajarín, M;Sánchez-Andrada, P;Alvarez, A
邻苯二甲醛与伯胺的缩合反应是合成邻苯二甲酰亚胺的经典方法。虽然相应的单亚胺的中间体偶尔被提出，但它们转化为邻苯二甲酰亚胺的机制仍有待阐明。我们给出的理论证据支持这一转化的三步机制路径，其中包括作为关键步骤的醛质子的[1，5]-H对映体重排生成中间体(氨基乙烯基)酮。据计算，其他替代路线在能量上不那么有利。还研究了5-氮杂-2，4-戊二烯骨架上的相关亚氨基醛通过[1，5]-H位移的类似转化。
Condensation reaction of o-phthalaldehyde with primary amines is a classical method for the synthesis of phthalimidines. Although the intermediacy of the corresponding monoimines has been occasionally proposed, the mechanism of their transformation into phthalimidines remains to be elucidated. We present here theoretical evidence supporting a three-step mechanistic pathway for that transformation involving the [1,5]-H sigmatropic rearrangement of the aldehydic proton leading to an intermediate (aminovinyl)ketene as the key step. Other alternative routes have been calculated to be energetically less favorable. Similar transformations of related imino aldehydes enclosing a 5-aza-2,4-pentadienal skeleton via [1,5]-H shifts are also studied.