THROUGH-BOND INTERACTIONS OF BETA-CARBONYL AND BETA-IMINE LONE PAIRS WITH CATIONIC 2P ORBITAL - QUANTUM CALCULATIONS ON BICYCLO[2.2.2]OCT-1-YL CATION AND DERIVATIVES

Semiempirical AM1 and ab initio STO 3G quantum calculations on bicyclo[2.2.2]oct-l-yl cation (11) and derivatives (12–25) substituted at C(2) or C(3) with electron-withdrawing groups such as Z = 0, NH, CH2, C(CN)2 or X = CN and N02suggested that the 3-oxobicyclo[2.2.2]oct-l-yl cation (13) and 3-(E)-iminobicyclo[2.2.2]oct-1-y1 cation (15) are more stable than expected on the basis of the inductive effect of their oxo and imino substituents, respectively. This phenomenon has been attributed to favorable through-bond n(CO) ↔σC(2),C(3) ↔p(C(l))+and n((E)-NH=C) ↔ σC(2),C(3) ↔ p(C(l))+interactions. This electron-releasing effect of the imino substituents is less important in the 3-(Z)-iminobicyclo[2.2.2]oct-l-yl cation (17). © 1990, American Chemical Society. All rights reserved.