On the Relative Resonance-Acceptor Abilities of CN, NO, COMe, CHO and NO2 Groups

2019-05-06T17:24:39Z (GMT) by Veejendra Yadav Arpita Yadav
<p>The relative resonance-acceptor ability based on ∆G<sup>‡</sup><sub>out</sub> is different from that based on ∆G<sup>‡</sup><sub>in</sub> for the conrotatory ring-opening of 3-carbomethoxycyclobutene bearing CN, NO, COMe, CHO and NO<sub>2</sub> as C1-substituent. In contrast, the relative resonance-acceptor ability based on s<sub>C3C4</sub>-p*<sub>C1C2 </sub>interaction in TS<sub>out</sub> is much the same as in TS<sub>in</sub>. It matches further with the acceptor ability based on the net of s<sub>C3C4</sub>-p*<sub>C1C2 </sub>and p<sub>C1C2</sub>-s*<sub>C3C4 </sub>interactions. The overall resonance-acceptor ability is estimated to be CN < COMe < CHO < NO<sub>2</sub> < NO from calculations at MP2/6-31+G(d,p) level of theory.</p>