Exocyclic Diastereotopic Protons as a Probe for Conformational Bias in Eight-Membered Rings Containing Phosphorus and Titanium

Abstract

The conformation in solution of eight-membered 12H-dibenzo[d,g][1,3,2]-dioxametallocin rings containing phosphorus and titanium, respectively, were studied by the NMR spectroscopy using ring substituents containing diastereotopic protons as a probe for conformational bias. The results of this study suggest that in addition to steric effects, an electronic effect due to donation of the lone pair of electrons on the ring oxygen atoms to the metal center influences the preferred conformation in solution.