Stannylation of Aryl Halides, Stille Cross-Coupling, and One-Pot, Two-Step Stannylation/Stille Cross-Coupling Reactions under Solvent-Free Conditions

Solvent-free protocols for palladium-catalyzed stannylation of aryl halides, Stille cross-coupling, and one-pot, two-step stannylation/Stille cross-coupling (SSC) are reported for the first time. (Het)aryl halides bearing acceptor, donor, as well as sterically demanding substituents are stannylated and/or coupled in high yields. The reactions are catalyzed by conventional palladium(II) acetate/PCy₃ [Pd(OAc)₂/PCy₃] under air, using available base CsF, and without the use of high purity reagents. The developed synthetic procedures are versatile, robust, and easily scalable. The absence of solvent, and the elimination of isolation procedures of aryl stannanes makes the SSC protocol simple, step economical, and highly efficient for the synthesis of biaryls in a one-pot two-step procedure.