Catalytic C(<i>sp</i>²)–C(<i>sp</i>³) Cross-Electrophile Coupling in Ptᴵᴵ–NaI–C₂H₃I–CH₃I–acetone System

Abstract

A new catalytic system for reductive C(sp²)–C(sp³) cross-electrophile coupling of was designed: Ptᴵᴵ iodo complexes in acetone solution containing an excess of NaI catalyzes the coupling of methyl iodide with vinyl iodide to form propylene. In parallel, the product of C(sp²)–C(sp²) coupling, 1,3-butadiene, is released in minor amounts. The total yield of the products based on the consumed vinyl iodide is almost quantitative. Under conditions of a large excess of methyl iodide, kinetics of vinyl iodide uptake follows pseudo-first-order law. The cross-coupling proceeds in a sequence of steps: oxidative addition of CH3I to Ptᴵᴵ iodo complexes to form methyl PtIV species – reduction of the latter with I– into the corresponding Ptᴵᴵ derivative – oxidative addition of C2H3I to the last one – reductive elimination of propylene from the intermediate methyl vinyl PtIV complex.