On the Di-1-naphthylcarbene−Dibenzofluorene Rearrangement and the Ethylenization of Diarylcarbinols
摘要:
Solution-spray flash vacuum thermolysis of di-1-naphthyldiazomethane (9) results in the formation of dibenzo[c,g]fluorene (12), formed via a carbene-carbene rearrangement of di-1-naphthylcarbene (10), The isomeric dibenzo[a,i]fluorene (11) claimed by Franzen and Joschek (Liebigs Ann. Chem. 1960, 633, 7) is not formed, and no dibenzofluorene is formed on thermolysis in boiling naphthalene. 11 is formed on dehydration of di-1-naphthylcarbinol (14) with phosphoric acid, but the claimed tetra-1-naphthylethylene (13) is not formed, and the so-called ethylenization of diarylcarbinols is cast in doubt generally. The compound previously believed to be 13 is 13-[di(1-naphthyl)methyl]-dibenzo[a,i]fluorene (22). The alleged cleavage of 13 into two molecules of carbene 10 is unsubstantiated.
The significance of Kekulé structures for the stability of aromatic systems
作者:E. Clar、W. Kemp、D.G. Stewart
DOI:10.1016/0040-4020(58)80037-x
日期:1958.1
with an aromatic frame work of alternating doublebonds with an odd electron or a positive charge in the centre. Tribenzoperinaphthene (XVI) is oxidised in acid solution with molecular oxygen to salts of the type (XVII), which are not paramagnetic. Combinations of two perinaphthyl radicals, (XVIII) or (XXI), go over either into the stable red hydrocarbon zethrene (XIX) with two fixed doublebonds in the