Enols of Amides. The Effect of Fluorine Substituents in the Ester Groups of Dicarboalkoxyanilidomethanes on the Enol/Amide and <i>E</i>-Enol/<i>Z</i>-Enol Ratios. A Multinuclei NMR Study<sup>1</sup>
作者:Yi Xiong Lei、Giovanni Cerioni、Zvi Rappoport
DOI:10.1021/jo010487+
日期:2001.12.1
symmetrical systems (R = R' = CH(2)CF(3)) show signals for the amide and the enol, but all systems with R not equal R' displayed signals for the amide and for two enols, presumably the E- and Z-isomers. The [Enol I]/[Enol II] ratio is 1.6-2.9 when R = CH(2)CF(3), R' = CH(3), CH(CF(3))(2) and 4.5-5.3 when R = CH(3), R' = CH(CF(3))(2). The most abundant enol display a lower field delta(OH) and a higher field delta(NH)