Studies On Sulfonylation Of β-dicarbonyl Compounds Promoted By Iodine

Sulfones belong to a known class of organosulfur compounds, which haveanti-microbial, anti-coagulant and anti-schistosomal activities and diverseapplication in organic synthesis, polymer materials, and medicinal chemistry,they have attracted much attention to people.We have developed two kinds of methods for sulfonylation of-dicarbonyl compounds mediated by iodine:(1) β-dicarbonyl sulfones couldbe produced by using I2/TBHP catalytic system with sodium sulfinates as thesulfonyl source;(2) β-dicarbonyl sulfones could also be prepared by usingI2/K2CO3combination, and Na2SO3-mediated C-C bond cleavage ofβ-dicarbonyl sulfones was proceeded to produce-keto sulfones.Initially, ethyl benzoyl acetate and sodium benzenesulfinate were selectedas model substrates to explore the optimal reaction conditions. The reactiontemperature, catalyst, oxidant and solvent influencing on the yield of reactionwere investigated, respectively. We obtain the best reaction conditions iodine asthe catalyst, TBHP as the oxidant, reaction temperature65℃and CH3CN2mL as solvent and obtain the yield of product reached94%. Then under theoptimal reaction conditions, a variety of β-dicarbonyl compounds and sodium benzenesulfinate were extended and corresponding products were obtained inideal yields.We investigated the reaction of dibenzoylmethane with sodiumbenzenesulfinate by using1.5equiv. of I2in2mL THF at room temperatureafter1.5h to get the target product yield was88%; then additive-mediated C-Cbond cleavage of β-dicarbonyl sulfones was proceeded to produce β-ketosulfones, using-acetyl acetophenone and sodium benzenesulfinate as standardreaction. The kinds of additives and dosage, the ratio of solvent and reactiontemperature influencing on the yield of reaction were investigated, respectively.We get the optimal reaction conditions the dosage of the additive Na2SO3is4equiv, THF and H2O volume ratio of1:1, reaction temperature60℃and theyield of product reached90%. Then under the optimal reaction conditions, avariety of β-dicarbonyl compounds and sodium benzenesulfinate were extendedand ideal yields were attained.In the whole experiment, we have synthesized47kinds of products and allof these products were examined by1H NMR、13C NMR、HRMS. We havedeveloped a method for the synthesis of β-dicarbonyl sulfones and β-ketosulfones with mild, high efficiency and operational simplicity and undermetal-free conditions.