Synthesis of CCl3-substituted amides, ketones, and indenes by intermolecular reactions of β-CCl3-enones or β-CCl3-β-hydroxy ketones with various nucleophiles in CF3SO3H

Abstract

Intermolecular reactions of 1-aryl-4,4,4-trichloro-3-hydroxybutan-1-ones (β-CCl₃-β-hydroxy ketones) or 1-aryl-4,4,4-trichlorobut-2-en-1-ones (β-CCl₃-enones) with nucleophiles in Brønsted superacid CF₃SO₃H (triflic acid, TfOH) result in various CCl₃-substituted compounds in good yields. Reactions with nitriles give rise to CCl₃-amides. Reactions with cyclohexane or 1,2,4,5-tetramethylbenzene as hydride ion sources afford products of ionic hydrogenation, namely, saturated CCl₃-ketones. Reactions with arenes furnish arylated CCl₃-ketones, which may be further cyclized into CCl₃-indenes. Plausible reaction mechanisms are discussed based on DFT calculations of electronic, orbital, and electrophilic properties of the intermediate cationic species.