Reactions of heterocumulenes with organometallic reagents: XVIII. Quantum-chemical study on the mechanisms of formation of thiophene ring from lithium and potassium buta-2,3-dienimidothioates
作者:V. A. Shagun、N. A. Nedolya
DOI:10.1134/s1070428011120104
日期:2011.12
thiophene ring from the most stable conformers and tautomers were localized. The formation of thiophene structure from lithium and potassium buta-2,3-dienimidothioates in two steps via intramolecular cyclization to thiophen-2(5H)-ylidene anion and its isomerization into thienylamide was found to be more probable. The activation barriers in both stepwise and concerted cyclization mechanisms considerably
丁酸锂和钾的不同异构体和互变异构体2,3-二亚氨基硫代酸酯(由甲氧基烯丙基碳负离子和异硫氰酸甲酯衍生的周围N,S中心阴离子加合物)作为3-甲氧基-N,N-二甲基噻吩的实际或潜在前体的热力学稳定性根据密度泛函理论,通过量子化学计算来估计-2-胺。梯度通道对应于从最稳定的构象异构体和互变异构体形成噻吩环的一致(一步)和逐步(两步)机制。通过分子内环化成噻吩-2(5 H发现亚)-亚烷基阴离子及其异构化成噻吩基酰胺的可能性更高。从锂到钾作为抗衡离子时,逐步和协同环化机理中的激活壁垒均大大降低。