Halogenation of β-keto-sulfones using KX/H₂O₂in aqueous medium: Synthesis of α-halo β-keto-sulfones and α-halomethyl sulfones

Abstract

Synthesis of α-halo β-keto-sulfones and α-halomethyl sulfones is described by the reaction of β-keto-sulfones with potassium halides in the presence of hydrogen peroxide in aqueous acidic medium afforded the corresponding α-halo β-keto-sulfones at room temperature in excellent yields. Further the α-halo β-keto-sulfones on treatment of aqueous alkali underwent base-induced cleavage to yield α-halomethyl sulfones.

Oxidative Halogenation with “Green” Oxidants: Oxygen and Hydrogen Peroxide

“…[95] Another example of the chlorination of active methylene compounds includes the oxychlorination of b-ketosulfones 62 with KCl (or KBr, KI) and a large excess of H 2 O 2 in an aqueous acetic acid medium to yield the a-halo-b-ketosulfones 63, which after hydrolysis give the a-halomethylsulfones 65 c or a,a-dihalo-b-ketosulfones 65 a,b by a second halogenation step (Scheme 20). [96,97] …”

Oxidative Halogenierungen mit umweltschonenden Oxidationsmitteln: Sauerstoff und Wasserstoffperoxid

“…Ein weiteres Beispiel für die Chlorierung von aktivierten Methylenverbindungen ist die Oxychlorierung von β‐Ketosulfonen ( 62 ) mit KCl (oder KBr, KI) und einem großen Überschuss von H 2 O 2 in verdünnter Essigsäure. Die gebildeten α‐Halogen‐β‐ketosulfone ( 63 ) können durch Hydrolyse in α‐Halogenmethylsulfone ( 65 c ) oder, in einem zweiten Halogenierungsschritt, in α,α‐Dihalogen‐β‐ketosulfone ( 65 a , b ) überführt werden (Schema ) 96. 97…”

KX/H2O2 - An Efficient and Non-Polluting Halogenating Reagent in Organic Synthesis

“…10 (B) a-Halo b-keto sulfones were synthesized by reaction of b-keto sulfones with potassium halide in the presence of hydrogen peroxide and acetic acid in aqueous medium. 11 Further, the a-halo b-keto sulfones on treatment with SO 2 Cl 2 /Br 2 afforded a,a-symmetrical and asymmetrical dihalo b-keto sulfones, 12 which on further treatment with aqueous alkali underwent base-induced cleavage to afford a,asymmetrical and asymmetrical dihalomethyl sulfones, respectively. This method is very simple, highly economical and eco-friendly for the synthesis of a wide variety of a-halo and a,a-dihalo b-keto sulfones.…”