Divinyl Sulfoxide: XI. Selective Addition of Carbonodithioate Anions to Divinyl Sulfoxide in the Water-Benzene System

Abstract

Selective monoaddition of carbonodithioate anions to divinyl sulfoxide gives rise to O-alkyl S-[2-(vinylsulfinyl)ethyl] carbonodithioates [ROC(S)SK, R = Et, Bu; 42350°C, 6 h, NaHCO 3 , aqueous benzene]. The activated double bond in vinyl sulfoxides is electrophilic and readily takes up various nucleophiles [234]. For example, the available divinyl sulfoxide [5] reacts with water (hydroxide anion [1], amines [6], alcohols (alkoxide anions) [7], thiols (thiolate anions) [8], and CH-acid anions [9] in the presence of proton carriers to form, depending on reagent ratio, mono-or diadducts in high or good yields. At the same time, no information on the possibility of reaction of vinyl sulfoxides with alkali metal carbonothioates is available, even though were this reaction accomplished, the reactivity of the vinylsulfinyl group would be better understood. Moreover, this reaction would provide new representatives of functionally substituted sulfoxides, perspective building blocks for synthesis of natural compounds [234], flotation agents [10], complexing solvents [11], and biologically active compounds [234, 12].Here we report for the first time on the reactions of vinyl sulfoxides with carbonodithioate anions in aqueous or aqueous-alkaline media. Divinyl sulfoxide (I) reacts with S-potassium O-ethyl and O-butyl carbonodithioates IIa and IIb in7776 H 2 O (C 6 H 6 ) NaHCO 3 Q S o S Q S Q S B S S o O RO IIIa, IIIb B Q S S B o O + ROCSK I IIa, IIb o S R = Et (a), Bu (b). ÄÄÄÄÄÄÄÄÄÄÄÄ 1 For communication X, see [1].aqueous or aqueous alkaline media to form monoadducts IIIa and IIIb even at a 1 : 2.5 molar ratio of reagents I and II.The reaction occurs at room temperature or under slight heating (40350oC) in the presence of sodium hydrocarbonate that acts as buffer to maintain the pH of the reaction mixture within 839.Obviously, the reaction occurs as nucleophilic addition of carbonodithioate ions to the double bond of divinyl sulfoxide to give carbanion A stabilized by resonance interaction with the neighboring S=O bond. Subsequent proton transfer from the water molecule completes the addition act. The reaction liberates the reactive hydroxide anion that, in its turn, can add to the double bond of sulfoxide I [1] or adduct III [3] and also to attack the carbonothioate function and cause its hydrolysis. 76 Q S Q S Q S B S o O RO C ! S o S 46 Q S Q SS B RO C S o S [ S g