Synthesis of o-deuterio- and o-halogeno-acetophenones via oxidation of η2-(2-acetylphenyl)tetracarbonylmanganese derivatives and the determination of a primary kinetic isotope effect in ortho-metallation of acetophenones

Abstract

2′-Deuterioacetophenone and 2′-deuterio-3′,4′,5′-trimethoxyacetophenone are obtained by reaction of the corresponding η²-(2-acetylphenyl)tetracarbonylmanganese compounds with cerium(IV) ammonium nitrate in CD₃CO₂D while 2′-iodo- and 2′-bromo-3′,4′,5′-trimethoxyacetophenone are similarly obtained using iodine monochloride and bromine respectively in CCl₄; the 2′-deuterioacetophenones can be used to establish primary kinetic isotope effect values (k_H/k_D) for ortho-metallation with PhCH₂Mn(CO)₅ of 3.2 (acetophenone) and 3.0 (3′,4′,5′-trimethoxyacetophenone).