Approaches toward the conformational analysis of carbocyclic hydroxyphosphono compounds: 13C–31P couplings and carbon shieldings

Abstract

13C nmr chemical shifts and 13C–31P couplings through one, two, and three bonds are reported for twelve carbocyclic hydroxyphosphonates and alkyl derivatives with all ring sizes from four to twelve, except the cyclodecyl system. On the basis of the vicinal couplings and carbon shieldings, inferences regarding preferred conformations are drawn. Evidence for ring flattening in some cyclohexyl compounds is presented. For a given ring size, it is demonstrated that 1Jcp becomes less positive as the degree of steric congestion about the C—P bond increases.