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In a series of 4-substituted camphors, in which the substituent, X, varies from ethyl through hydrogen to nitro, we have shown that the enthalpies of complexation, with BF3 in dichloromethane, which cover a range of 14.5 kJ mol–1 correlate well with r > 0.99 with polar substituent constants with the sensitivity ρ*ca. 8.IR spectroscopy of the free ketones and the more polar BF3 complexes indicates that the latter are ca. 1.44 times more sensitive to substituent variation.Complexation occurs at both sites when X = OAc and only at the ketone when X = CO2Me.We rationalise the smaller sensitivity of the protons to substituent-induced 1H shift displacement when in the E-complexed form to the electron-attracting effect of complexation that leads to diminished electronic screening. The 4JH3exo–H5exo coupling is diminished by complexation which enhances hyperconjugation between the C(3)–Hσ and the carbonyl p orbitals to the detriment of back lobe C(3)–H3exo–C(5)–H5exoσ–σ overlap. A number of chemical shift and coupling correlations are reported.

The synthesis, characterisation and reactivity are reported for the title compound which is the first isolable compound of type RIF2 from an aliphatic iodide.

A controversy about the structures of five-membered ring sultones obtained by treatment of camphenes with acetic and concentrated sulfuric acids has been resolved by X-ray analysis of the sultone obtained from racemic camphene, namely, endo-3H-10,10-dimethyl-4-oxa-5-thiatricyclo[5.2,1.0 3,7 ]decan S,S-dioxide, (also known as 10-bornanesulfonic acid 2-hydroxy-γ-sultone), C 10 H 16 O 3 S. Five-membered saturated sultone rings are shown to be conformationally flexible.

Molecules of 13H-dibenzo­[a,i]­fluoren-13-one, C21H12O, strad­dle a crystallographic mirror plane and are essentially planar, with a dihedral angle of only 1.9 (1)° between the two naphtha­lene ring systems. Repulsive intramolecular C=O⋯H interactions therefore do not explain the larger distortions found in isomeric ketones.