Modern Friedel-Crafts Chemistry. Part-XVII. Studies on the Acid-catalysed Dehydration of 3-(α-Naphthylmethyl)-3-pentanol, 2-(α-Naphthyl)-1, 1-diphenyl-1-ethanol and 2-Methyl-2-(α-naphthyl)· 2-butanol

Department of Chemistry, Faculty of Science, KAAU, P.O.Box 9028, Jeddah 21413, Saudi Arabia Manuscript received 10 January 1992, accepted 23 March 1992 The title α-naphthylalkanols were prepared by unequivocal methods and their dehydration patter was examined in the pre­sence of both Lewis and Brӧnsted-Lowry acid-catalysts. 3-(α-Naphthylmethyl)-3-pentanol (5) gave acyclidehydration mix­ture of 1,1-diethylacenaphthene (10, mainly) and 2-ethyl-1-methyl-2,3-dihydrophenalene (11) with AICI3/CH3NO2 and an acyclidehydration mixture of 2-methyl-1-(α-naphthyl)-1-butene (12) and Z- and E-3-(α-naphthylmethyl)-2-pentene (13) with 85% H2SO4, PPA or NaHSO4. 2-(α-Naphthyl)-1,1-dipheny1-1-ethanol (6) gave 1-(α-naphthyl)-2,2-diphenylethene (16) with H2SO4, PPA, NaHSO4 but a different unidentified product with AlCI3/CH3N0a .Finally, 3-methy1-2-(α-naphthyl)-2-hutanol­(7) gave 1,1,2-trimethyl-acenaphthene (18) with AICI3/CH3NO2,but 2-methyl-3-(α-naphtliy)-2-butene (19) with 85% H2SO4 or NaHSO4. Both reactants and products were characterised by elemental, spectral, chemical and glpc analysis. Mecha­nistic interpretations have been given in terms of carbocation reactions and rearrangements