Semidiones. VI. Bicyclo[2.2.2]octane-2,3-semidione and derivatives

13C nuclear magnetic resonance studies. 58. 13C spectra of a variety of bicyclo[2.2.2]octane derivatives. Further definition of the deshielding δ effect

“…Following the procedure described by Russell et al (14) from 1,3-cyclohexadiene and maleic anhydride, olefin 10, alcohol 21, and ketone 16 were generated. Reduction of 16 with LiAlH4 furnished a sample of 22, the physical and analytical data for which are listed in'Table 1.…”

“…The Diels-Alder reaction of 1,3-cyclohexadiene with acryloyl chloride gave a mixture from which bicyclo[2.2.2]oct-2-ene-endo-5-carboxylic acid was isolated (15) after hydrolysis. This acid was reduced to the hydroxymethyl derivative, converted to the tosylate, and then to olefin 8 using the sequence described by Russell et al (14). Hydrogenation over PtOz gave 1.…”

Semidiones derived from bicyclic hydrocarbons

“…These and o other applications of the ESR study of semidiones have been reviewed (8)(9)(10) (11,12). First, note the absence (or extremely small) interaction of the bridgehead hydrogens in e, whereas the bridgehead hydrogens in d have appreciable spin density.…”

“…In e, 0 = 90", and one predicts no interaction by this directed mechanism (hyperconjugation), whereas in d, 0 < 90°, and this hydrogen does interact with the unpaired spin. Secondly, note that all the j3-hydrogens which interact in these systems, with the exception of the syn-7-hydrogen in This relationship of bonds is very important in both NMR (14, 15) and ESR (11,12) couplings and will be utilized many times in this thesis to assign hyperfine splittings.…”

“…In general, semidiones have been prepared by the methods in Chart I. In certain bicyclic systems, such as (12), so one must resort to a higher oxidation state such as the diketone or a-hydroxy ketone.…”