Carbon-carbon bond construction using boronic acids and aryl methyl sulfides: orthogonal reactivity in Suzuki-type couplings

The Rh(I)-catalysed coupling of aryl and alkenyl boronic acids with simple aryl and alkenyl methyl sulfides is reported. The process employs bench-stable Rh(I) precatalysts incorporating small bite-angle chelating phosphine ligands (R2PCH2PR2, R = Pr-i, Cy), shows good functional group tolerance, and proceeds under mild reaction conditions. Importantly, aryl bromide activating groups are inert to the reaction conditions, allowing selective reaction at either a methyl sulfide or bromide activating group, depending on catalyst (metal) choice. The scope of the coupling reactions, their combination with Rh-catalysed hydroacylation reactions in cascade processes, together with preliminary mechanistic studies, are all documented.