Nickel-catalyzed coupling reaction of sterically congested cis bromides and lithium alkenylborates

Article abstract of DOI:10.1016/S0040-4020(97)10206-X

Lithium alkenyl berates of general structure 5 (R(T) = alkenyl) couple with cis bromides 1 at room temperature overnight in the presence of NiCl₂(PPh₃)₂ as a catalyst to furnish dienes of general structure 3 with retention of the olefin geometries present in both coupling partners. By using this reaction, cis,trans dienes 3 (R = TBDMS, TES, TBDPS; R¹ = n-C₅H₁₁, c-C₆H₁₁; R² = H; R³ = n-C₅H₁₁, Ph) and cis,cis diene 3 (R = TBDMS; R¹ = R² = n-C₅H₁₁; R³ = H) are synthesized in good yields.