Site-Selective C-C Bond Formation Using Cyclodextrin as Catalyst

Abstract

Selective formylation of phenol at the 4-position is achieved by using β-cyclodextrin as catalyst in the reaction of phenol with chloroform in aqueous alkali. The reactions of 1, 3-dihydroxybenzene and indol, respectively, in the place of phenol give 2, 4-dihydroxybenz- aldehyde and indole-3-aldehyde in virtually 100% selectivies and high yields. The reactions of para-substituted phenols, 4-methylphenol and 5, 6, 7, 8-tetrahydro-2-naphthol, instead of phenol, effect the selective dichloromethylation at the para-positions. Selective carboxylation of phenol at the 4-position is achieved in the reaction of phenol with carbon tetrachloride in aqueous alkali by using β-cyclo-dextrin and copper powder as catalyst.