An annelated[14]annulenedione (V) was prepared by the Castro reaction of cuprous salt of o-iodocinnamoylacetylene (IV) in order to examine the aromatic character of the inner fourteen membered ring. The NMR spectra of V in arsenic trichloride and deuterotrifluoroacetic acid suggest that significant downfield shift of the inner protons HB is due to a paramagnetic ring current arising from polarization of two carbonyl groups in the inner ring, compared with the spectra of a reference compound VI.
通过邻碘肉桂酰乙炔的亚铜盐(IV)的卡斯特罗反应制备了环化[14]环烯二酮(V),以研究 14 个成员内环的芳香特性。V 在三氯化砷和三氟乙酸中的核磁共振光谱表明,与参考化合物 VI 的光谱相比,内环质子 HB 的显著下移是由于内环中的两个羰基极化产生了顺磁环电流。