Promoted by samarium diiodide in THF, the α,β-unsaturated alkynones were reduced to afford intermolecular reductive coupling products. The multiply substituted cyclopentadienes were prepared conveniently in good yields. Promoted by samarium diiodide in THF, the α, β-unsaturated alkynones were reduced to afford intermolecular reductive coupling products. The multiply substituted cyclopentadienes were prepared conveniently in good yields.