MODERN FRIEDEL-CRAFTS CHEMISTRY .17. STUDIES ON THE ACID-CATALYZED DEHYDRATION OF 3-(ALPHA-NAPHTHYLMETHYL)-3-PENTANOL, 2-(ALPHA-NAPHTHYL)-1,1-DIPHENYL-1-ETHANOL AND 2-METHYL-2-(ALPHA-NAPHTHYL)-2-BUTANOL

The title alpha-naphthylalkanols were prepared by unequivocal methods and their dehydration patter was examined in the presence of both Lewis and Bronsted-Lowry acid-catalysts. 3-(Alpha-naphthylmethyl)-3-pentanol (5) gave acyclidehydration mixture of 1,1-diethylacenaphthene (10, mainly) and 2-ethyl-1-methyl-2,3-dihydrophenalene (11) with AlCl3/CH3NO2 and an acyclidehydration mixture of 2-methyl-1-(alpha-naphthyl)-1-butene (12) and Z- and E-3-(alpha-naphthylmethyl)-2-pentene (13) with 85% H2SO4, PPA or NaHSO4. 2-(Alpha-naphthyl)-1,1-diphenyl-1-ethanol (6) gave 1-(alpha-naphthyl)-2,2-diphenylethene (16) with H2SO4, PPA, NaHSO4 but a different unidentified product with AlCl3/CH3NO2. Finally, 3-methyl-2-(alpha-naphthyl)-2-butanol-(7) gave 1,1,2-trimethyl-acenaphthene (18) with AlCl3/CH3NO2 but 2-methyl-3-(alpha-naphthyl)-2-butene (19) with 85% H2SO4 or NaHSO4. Both reactants and products were characterised by elemental, spectral, chemical and gIpc analysis. Mechanistic interpretations have been given in terms of carbocation reaction and rearrangements.