Aromaticity of the Bergman, Myers-Saito, Schmittel, and directly related cyclizations of enediynes.
Aromaticity of the Bergman, Myers-Saito, Schmittel, and directly related cyclizations of enediynes.
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DOI：
10.1021/jo015728s
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发表时间：
2002-02
期刊：
影响因子：
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通讯作者：
F. Stahl;D. Moran;P. von Ragué Schleyer;M. Prall;P. Schreiner
中科院分区：
文献类型：
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作者：
F. Stahl;D. Moran;P. von Ragué Schleyer;M. Prall;P. Schreiner
在(UBS)-BLYP/6-31G*下评价的二炔和烯丙烯环化反应的芳香性标准(磁化率升高、核独立化学位移(NICS)和芳香族稳定能(ASE)评估)都同意由Bergman(3)和Myers-Saito反应(5)形成的苯系的环电子离域程度与苯相当。母体环化反应和它们的苯环类似物之间的反应热差异并不完全是由于在反应过程中获得的酶的差异。富烯双自由基的交替形成并不伴随着良好的芳香效应。
Aromaticity criteria (magnetic susceptibility exaltations, nucleus independent chemical shifts (NICS), and aromatic stabilization energy (ASE) evaluations) for enediyne and enyne-allene cyclizations evaluated at (UBS)-BLYP/6-31G* all agree that the degrees of cyclic electron delocalization of the benzenoid systems formed by the Bergman (3) and Myers-Saito reactions (5) are comparable to benzene. The reaction enthalpy differences between the parent cyclizations and their benzannelated analogues are not entirely due to disparities in gained ASE during the reactions. The alternative formation of fulvene biradicals is not accompanied by favorable aromatic effects.