Conformational studies of 9,10-ditolylphenanthrenes: high rotational barriers for the syn?anti interconversion

Equilibria and barriers to interconversi

Equilibria and barriers to interconversion between the syn and anti conformers in 9-(o-substituted phenyl)fluorenes obtained by photorearrangement of triptycenes

✍ Hideyuki Tukada; Michiko Iwamura; Tadashi Sugawara; Hiizu Iwamura 📂 Article 📅 1982 🏛 John Wiley and Sons 🌐 English ⚖ 684 KB

The population ratios of the syn to the anti conformers in 9-(2-~ubstituted phenylMuorenes have been determined by 'H NMR spectroscopy to range from 0.25 (for 2'-NHz) to >20 (2'-CH=NNH-CJ&(NOZ)-2,4). They appear to increase, firstly, with the steric bulk of the 2'-substituents and, secondly, with th