title: 2,2,6,6-Tetramethylpiperidine-catalyzed, ortho-selective chlorination of phenols by sulfuryl chloride.
abstract: 2,2,6,6-Tetramethylpiperidine (TMP)-catalyzed (1-10%) chlorinations of phenols by SO2Cl2 in aromatic solvents are more ortho selective than with primary and less hindered secondary amine catalysts. Ortho-selective chlorination is successful even with electron deficient phenols such as 2-hydroxybenzaldehyde and 2'-hydroxyacetophenone. Notably, ortho selectivity increases with the reaction temperature. On the other hand, tetraalkylammonium chloride-catalyzed chlorinations are moderately para selective.
authors: Department of Chemistry, MS 015, Brandeis University , Waltham, Massachusetts 02454-9110, United States.
authors: Noam I
authors: NI
authors: Saper
authors: Barry B
authors: BB
authors: Snider