Couplings over More than Three Bonds and Through Space

10 Couplings over More than Three Bonds and Through Space 

The vicinal and allylic four-bond proton-proton couplings for ribafutinol, a reduced form of a naphthalenic ansamycin (ribafutin) have been applied by Santos et al in the elucidation of the three-dimensional structure of this compound. Full sets of the Jhh couplings have been reported for both ribafutin and ribafutinol. 

The effect of stereoelectronic interactions on three- and four-bond proton-proton couplings in hydrocarbons has been studied by Sproviero and Burton.  

The proton-proton couplings across three, four and five bonds have been determined and analysed by Kania et al in their studies on the structure of a series of derivatives of 5,6,ll-trimethyl-6. -indolo[2,3-h]quinolinium methyl-sulfate. 

The stereospecifity of the proton-proton couplings across five bonds has been applied by Garrigues in elucidation of the conformation of derivatives of thiophene in solution. 

The conformations of cis- and trans-cyclopentane-1,3-diol have been studied by 

Abraham and Koniotou by the use of NMR spectroscopy and by ab initio and molecular mechanics. The complete analysis of the H NMR spectra yielded all the H-H couplings for the cis isomer including a long-range Vhh coupling between H-2cis and H-4,5cis. 

A detailed NMR analysis of a cyclic allylsilane, [(2R, 3S )-l,l-diphenyl-2-vinyl-l,2,3,6-tetrahydrosilin-3-ol],has been performed by Mahieux et yielding a set of proton-proton couplings including the allyhc Vhh and homoallylic Jhh ones. These values have been used as NMR constraints to calculate the 3D structure of the compound. 

The steric and electronic structure of 2-(2-acylethenyl)pyrroles has been studied by Ushakov et alf by the use of NMR including Vhh and Vhh couplings. 

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Couplings over more than three bonds and through space 209... 

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