Alumination of resorcinol and hydroquinone. An easy access to bifunctional Lewis acids

The reaction of trimethylaluminum with hydrochinone and resorcinol produces [(1,4-(Me2AlO)(2)C6H4)-THF](2) (1) and [(1,3(Me2AlO)(2)C6H4)-THF](2) (3) respectively. Compounds 1 and 3 are poorly soluble in common solvents but readily dissolve in pyridine to give the corresponding adducts (1,4-(Me2AlO)(2)C6H4)-(Py)(2) (2) and (1,3-(Me2AlO)(2)C6H4)-(Py)(2) (4). The reaction of 4,6-dichlororesorcinol with trimethylaluminum produces the soluble chlorinated analog of compound 3 [(1,3-(Me2AlO)(2)-4,6-Cl2C6H2)-THF](2) (5) As indicated by NMR, the dimeric structure of 5 is fluxional in solution. Upon addition of chloride or t-butoxide anions to solution of 5 in THF, Al-27 NMR monitoring indicates that there is formation of anionic complexes but that the chelation of the anionic hosts by the two aluminum centers present in the [1,3-(Me2AlO)(2)-4,6-Cl2C6H2] unit does not occur. (C) 1997 Elsevier Science S.A.