Syntheses and reactions of some fluorinated dienes,cyclobutenes and furans

There are many reports¹ of the pyrolysis of fluorinated organic compounds, including the defluorination of cyclic fluorocarbons over iron to give aromatic compounds. Extending this technique we have investigated the flow pyrolysis of some readily accessible unsaturated fluorocarbons, such as I, II, and III, and found these to be synthetically

useful routes to fluorinated dienes, cyclobutenes, and furans. Pyrolyses were carried out using a nitrogen flow over platinum, iron or caesium fluoride heated at 430–700°. The various products can all be rationalized in terms of intermediate allylic radicals, and the solid substrate influences which allylic radicals are formed.We are also investigating the chemistry of those now accessible compounds, such as IV, V, and VI, and some of the preliminary results are described.

For example the fluoride ion induced dimerisation of IV gave two major products VII and VIII via a particular interesting mechanism.

     

Adduct of nonamethylferrocenecarbaldehyde with HBF4 and its transformations

Some reactions of the adduct of nonaniethylferrocenecarbaldehyde with HBF₄, [Me₅C₅FeC₅Me₄CH⁺(OH)]BF₄ ^–, and its transformation into the paramagnetic complex [Me₅C₅Fe^+-C₅Me₄CH=O]BF₄ ^– were studied. The structure of the complex was established from the chemical properties, the data from IR spectroscopy, mass spectrometry, and¹H,¹³C, and¹⁹F NMR spectroscopy and confirmed by independent synthesis.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp, 2979–2983, December, 1996.     

Molecular structure of the chelate complex (3,5-dimethylbenzyl)diphenylphosphitodicarbonyl-chromium

The chelate phosphitoalkylarenedicarbonylchromium complex has been studied by single-crystal X-ray diffraction. The presence of the short bridge (CH₂O) leads to noticeable distortions of the molecular geometry which may be the reason why complexes of this type containing one more chelate cycle of the same size could not be isolated. The CrP bond in the complex 2.201 Å, is the shortest CrP bond reported thus far.