Synthetic and Theoretical Studies of Cyclobuta[1,2:3,4]dicyclopentene. Organocobalt Intermediates in the Construction of the Unsaturated Carbon Skeleton and Their Transformation into Novel Cobaltacyclic Complexes by C−C Insertion
作者:Andrew G. Myers、Miki Sogi、Michael A. Lewis、Stephen P. Arvedson
DOI:10.1021/jo030368p
日期:2004.4.1
kcal/mol higher in energy than the isomeric hydrocarbon 1,6-didehydro[10]annulene (2), a molecule known to isomerize to 1,5-didehydronaphthalene (4) above −50 °C. Calculated enthalpic changes of homodesmotic reactions support the notion that 1 is an aromatic molecule with a resonance stabilization energy (RSE) about half to two-thirds that of benzene on a per-molecule basis. Investigations of potential
描述了三环10π-电子烃环丁[1,2:3,4]二环戊烯(1)的理论和合成研究,这是一种从未合成的名义上的芳香结构。通过密度泛函理论计算(B3LYP / 6-31G(d,p))进行的几何优化预测1是具有非交替的C单键和双键的D 2 h对称结构。计算还预测,1为4.7千卡/摩尔的能量比异构烃1,6-二脱氢更高[10]轮烯(2),公知的异构化为1,5- didehydronaphthalene(分子4高于-50)℃的。计算的同态反应的焓变支持以下观点:1是在每个分子的基础上具有约苯的共振稳定能(RSE)的芳香族分子的三分之二至三分之二。对1的潜在合成途径的研究最初将三环碳酸酯11(一种分子内[2 + 2]-光环化反应的产物)用作原料。在这些研究中,将11分几步转化为二萘烷12,该二萘烷经氟化硼乙醚醚处理后形成了不稳定的烃双环戊二烯基(13)。为了避免不饱和三环的中心四元环的断裂[5.3.0.0 2