Synthesis and Mechanistic Investigations in Bicyclic Compounds

[摘要] A series of 4-substituted isoborneols has been synthesised in order to investigate, by infrared spectroscopy, the field effects of 4-substituents on the hydroxyl group stretching frequency, v(OH), of isoborneols. The rather low sensitivity to substituent field effects of the free hydroxyl group stretching frequency of the 4-substituted isoborneols is attributed to the separation of the O-H and C-X bonds and to the low polarity of the O-H bond. The corresponding property of the more polar hydrogen-bonded hydroxyl group is about forty times more sensitive to substituent variation. A range of N-nitroimines in dilute solutions of methyltetrahydrofuran and CD3OD, exposed to 60Co gamma-rays at 77 K, gave the corresponding radical anions, detected by EPR spectroscopy. Analysis of the spectra show that the radical anions of the aliphatic N-nitroimines have the unpaired electron in the pi*-NO2 molecular orbital and that the radical anion of the aromatic N-nitroimines is delocalised in the aromatic pi* molecular orbitals. The EPR spectra of the radical anions of a range of nitroalkenes, prepared in the solid state by similar methods, have been studied and compared with the radical anions of the N-nitroimines. Analysis of the EPR spectra indicates that the unpaired electron in the radical anions of the N-nitroimines is more centred on the nitro group than in the nitroalkenes. As a result of the second order Beckmann rearrangement of its camphor oxime ether derivative, the first synthesis of 4-fluoro-3,5-dinitrophenol is reported. As a consequence, 4-trimethylsilylbutan-2-one oxime is investigated as a protected alcohol species. The novel compound (+)-alpha-oximino-5,6-dehydrocamphor has been synthesised. Attempts to oxidise this compound to its alpha-diketone derivative has thus far been unsuccessful. The synthesis, characterisation and reactivity are reported for 4-(difluoroiodo)tricyclene, the first isolable compound of the type RIF2 from an aliphatic iodide.

[发布机构] University:University of Glasgow

[关键词] Organic chemistry