Yoshihiro Saeki

Ab initio MO study of benzylic cations?1. Some theoretical parameters related to the resonance demand in the Yukawa-Tsuno equation

Structures of 14 kinds of benzylic cations into which are introduced various substituents at benzylic position were optimized by means of the ab initio molecular orbital method at the RHF/6-31G* level. The theoretical indices obtained associated with the resonance interaction, such as population, bond order and bond length, were compared with the resonance demand parameter (r value) of corresponding solvolysis systems that were given by the Yukawa-Tsuno substituent effect analysis. The r value was linearly correlated with the theoretical resonance indices.

Substituent effect on the solvolysis of α-t-butyl-α-methylbenzyl chlorides

Abstract The substituent effect on the solvolysis rates of α-t-butyl-α-methylbenzyl chlorides in 80% aq. acetone was correlated to give ϱ=−4.3 and r=0.91 in terms of the LArSR Eq. (1). This slightly reduced r value relative to full conjugation corresponds to a deviation by θ=24.5° from the coplanarity of the benzylic π-system.

The importance of resonance stabilization in the benzylic solvolysis. Substituent effects on the solvolysis of α,α-diisopropylbenzyl chlorides

The substituent effect on the solvolysis of α,α-diisopropylbenzyl chlorides can be described in terms of σ+ value. No significant steric loss of resonance was observed by introducing two bulky isopropyl groups into benzylic reaction center.

Oxygen-18 scrambling studies in the solvolysis of benzyl tosylates

The ion-pair return process during the solvolysis of benzyl tosylates was studied in typical solvents by means of the sulfonate18O-scrambling experiments using carbon-13 NMR spectroscopy. The substituent and solvent dependency of amount of ion-pair return in this borderline solvolysis was discussed.