Biphenyls Synthesis Via Pd-Catalyzed Desulfitative Coupling Of Sodium Sulfinates

The biphenyls is an extremely important chemical intermediate widely used in the field of Pharmaceuticals, pesticides, dyes and organic conductors. There are many synthetic methods, of which an important synthesis of organometallic cross-coupling reaction of these compounds.In this paper, palladium acetate as catalyst, the presence of phosphorus ligands, the desulfitative coupling of aromatic sulfinic acid sodium salts with aryl halides was investigated. The effects of phosphorus ligands and solvent on the reaction optimization to get the best conditions of desulfitative coupling of aromatic sulfinic sodium salts with aryl bromides to achieve a2mol%Pd(OAc)2catalyst,2mol%dppp ligand, dioxane solvent,150℃,12h high yield conversion.On the basis of reaction above, we further study the desulfitative coupling of aromatic sulfinic sodium salts with Ar-OTf, Ar-OTs, Ar-OMs, Ar-IMs. The impact of phosphorus ligands and solvent on the reaction to optimize the best conditions of desulfitative coupling of aromatic sulfinic sodium salts with Ar-OTf,2mol%Pd(OAc)2catalyst,4%Xphos ligand, toluene at120℃,24h preferably conversion.We explore the substrate scope and functional group tolerance, analysis of electronic and steric effects for the reaction. For aromatic sulfinic sodium salts, neutral groups and electron-donors are more conducive to the reaction carried out smoothly, while electron-withdrawing groups favor the reaction, for Ar-OTf, electron-withdrawing groups are more conducive to the reaction carried out smoothly, while electron-donors is not conducive to the reaction. Steric effect of the reaction is not obvious.We compared the level of desulfitative coupling of aromatic sulfinic sodium salts with different sulfonates electrophilic reagent. Higher reactivity of Ar-OTf satisfactory yield, of Ar-IMs are of low reactivity, and there is a considerable dependence on solvents and other conditions, of Ar-OTs reactivity is undoubtedly the lowest,No matter how changed conditions have shown a strong inert, with little or basic does not react.