Pd-Catalyzed Sulfonylation Of Vinylcyclopropanes

Organosulfur compounds such as sulfones and thioethers are versatile in synthetic chemistry,and have found diverse applications in agrichemicals,pharmaceuticals,and materials science.In particular,allylic aryl sulfones exhibit a variety of pharmacological properties,including antifungal,antitumor,anti-inflammatory,and anti-HIV activities,and their derivatives are widely found in many bioactive natural products and some of the best-selling drugs.Herein,an efficient Pd(0)-catalyzed sulfonylation of vinylcyclopropanes(VCPs)with p-tosylmethyl isocyanide(TosMIC)was studied in this paper.In air atmosphere,the reaction was carried out by using electron withdrawing groups substituted vinylcyclopropanes as substrates,TosMIC as sulfonation reagent,Pd2(dba)3-CHCl3 as catalyst,1,3-bis(diphenylphosphino)propane(dppp)as diphosphine ligand,cesium carbonate(Cs2CO3)as base and 1,2-dichloroethane(DCE)as solvent.Allylic sulfones was synthesized in good yield and high regioselectivity via a sequential C-C bond and C-S bond cleavage and a new C-S bond formation process onto the in situ formed Pd intermediate.The main research contents are as follows:Diethyl vinylcyclopropane dicarboxylate and p-tosylmethyl isocyanide were used as template reaction substrates to explore and determine the optimal reaction conditions.Under the optimized conditions,vinylcyclopropanes and sulfonylmethyl isocyanide derivatives were systematically investigated respectively.The results showed that the reaction system had good universality,with the highest yield reaching 89%,E/Z>99:1(Scheme 1).According to related literature reports,the possible mechanism of the reaction was proposed.