Diheteroarylmethanes. 5.<sup>1</sup> <i>E</i>−<i>Z</i> Isomerism of Carbanions Substituted by 1,3-Azoles: <sup>13</sup>C and <sup>15</sup>N π-Charge/Shift Relationships as Source for Mapping Charge and Ranking the Electron-Withdrawing Power of Heterocycles
作者:Alessandro Abbotto、Silvia Bradamante、Giorgio A. Pagani
DOI:10.1021/jo951884l
日期:1996.1.1
pi-charge mapping in these carbanionic systems, and the results point to considerable delocalization of the electron pair(s) of the oxygen and pyrrolic nitrogen atoms at position 1 in oxazole and imidazole toward the pyridic nitrogen at position 3 of the rings (in both the neutrals and the carbanionic species). On the contrary, not only does the sulfur atom in thiazole derivatives not delocalize any negative