Syntheses and chiroptical properties of some optically active decahydroquinoline nitroxide radicals
The syntheses of five optically active nitroxide radicals of the 2,2,8a-trimethyldecahydroquinoline type are described, together with their o.r.d. and c.d. spectra. In the case of (–)-trans-2,2,8a-trimethyloctahydro-4-oxoquinolin-1-oxyl (24), evidence is presented which indicates that the signs of the back octants associated with the nitroxide chromophore are the same as those dictated by the carbonyl Octant Rule. On this basis conformational assignments are suggested for other six-membered ring nitroxides in this series.