The proton magnetic resonance spectra of some triheteroarylphosphine oxides and heteroarylphosphonates
Abstract
The 1H n.m.r. analysis of a number of phosphorylated derivatives of furan, thiophen, and pyrrole are reported. The results indicate that some degree of dπ–pπ bonding is present. The chemical shifts and coupling constants are similar to those found in the 2-formyl derivatives of furan, pyrrole, and thiophen. This conjugative interaction is found to be more important in the phosphorylated furans and thiophens than in the pyrroles.