Formation of mono- and dianions of polycyclic hydrocarbons through deprotonation with the alkylithium-N,N,N',N'-tetramethylethylenediamine complex. Convenient general method of dehydrogenation
Proton magnetic resonance of some 9,10-dihydroanthracenes
作者:W. Carruthers、G. E. Hall
DOI:10.1039/j29660000861
日期:——
m.r.) spectrum of the 9,10-di-t-butyl compound shows that it has either a planar conformation of the central ring or the trans configuration with rapid interconversion of the two conformers. Homo-allylic coupling is observed in the n.m.r. spectra of 9-t-butyl-9,10-dihydroanthracene and 1-phenyl-1,4-dihydronaphthalene, in the latter case with a coupling constant of 6 c./sec.
Conformational analysis of 9,10-dihydroanthracenes. Molecular mechanics calculations and carbon-13 NMR
作者:Peter W. Rabideau、Jennifer L. Mooney、Kenny B. Lipkowitz
DOI:10.1021/ja00286a002
日期:1986.12
The conformational analyses of 9, 10-dihydroanthracene and several of its methylated and ethylated derivatives are studied by empirical force field calculations (MM2 and MMPI). The computational results are considered in light of previous and current carbon NMR data. Model compounds are examined which involve fixed, planar, and boat-shapedconformations about the central ring, and these /sup 13/C NMR
Crystal and molecular structure of 10-substituted 9-anthracenones. Substituent size as the controlling factor for the nonplanarity of the central ring
作者:Andrzej Sygula、Renata Sygula、Frank R. Fronczek、Peter W. Rabideau
DOI:10.1021/jo00038a011
日期:1992.6
MM2 calculations for a series of 10-R-9-anthracenones demonstrate an increase of the folding of the central ring with increasing size of the substituent. All the substituents considered prefer the pseudoaxial position except fluorine, which prefers the pseudoequatorial orientation. The anthracenone moiety approaches planarity when the size of the substituents approaches the size of the hydrogen atom. The planar conformation for 9-anthracenone is also shown by vibrational frequency calculations to be a true potential energy minimum at the ab initio 3-21G level. X-ray structure determination shows that 10-R-9-anthracenones (R = Me, iPr, tBu, Ph, and Br) generally exhibit the structural features predicted by MM2 calculations for the isolated molecules. However, 10-Me and 10-Ph-9-anthracenones are found to be significantly less folded than calculated by MM2, the discrepancy being attributed to the crystal packing forces. Consideration of the theoretical as well as the experimental results leads to the conclusion that the parent 9-anthracenone is expected to be planar in the crystal state.