9,10-DIMETHYL- AND 9,10-DIPHENYL-9,10-DIHYDRO-9,10-ETHANO-ANTHRACENE BY FRIEDEL–CRAFTS CYCLIALKYLATIONS OF 1,4-DIARYLSUBSTITUTED-1,4-DIOLS

The 1,4-diols, 2,5-diphenylhexane-2,5-diol (Ia), and 1,1,4,4-tetraphenylbutane-1,4-diol (Ib) were found to undergo intramolecular cyclodehydrations and dehydration yielding 9,10-disubstituted-9,10-dihydro-9,10-ethanoanthracenes, 2,2,5,5-tetrasubstituted-tetrahydrofurans, and 1,1,4,4-tetrasubstituted-1,3-butadienes when treated with hydrogen fluoride or aluminium chloride. No evidence could be found for intermolecular cyclialkylations of added aromatics such as benzene, anisole, or veratrole. Nuclear magnetic resonance spectra of the products are discussed.