Hall et al., Journal of the Chemical Society, 1956, p. 3475,3480
作者:Hall et al.
DOI:——
日期:——
How advantageous is the intramolecular aggregation of 1,4-organodilithio compounds ?
作者:Olivier Desponds、Manfred Schlosser
DOI:10.1016/s0040-4020(01)90443-0
日期:1994.1
1,11-Dilithio-5,5,7,7-tenamethyl-5,7-dihydrodibenz[c,e]oxepin (3) is a conformationally confined analogue of o,o'-dilithiobiphenyl (1). A temperature variable nmr study of this model compound, monitoring the coalescence of its diastereotopic methyl groups, has revealed a barrier of about 12 kcal/mol to planarization, just 2 kcal/mol less than that found with the metal-free heterocycle. Thus, the energetic benefit of intramolecular aggregation of o,o'-dilithiobisaryls is found to be significantly smaller than predicted by ab initio calculations.
234. Organic molecular compounds. Part III. Compounds of phenols with some synthetic cyclic oxides