Catalytic addition of silylacetylenes to alpha,beta-unsaturated ketones proceeded in the presence of a cobalt complex coordinated with a bisphosphine ligand to give high yields of beta-alkynylketones.
Rhodium-catalyzedasymmetric conjugate alkynylation of α,β-unsaturatedketones giving β-alkynylketones took place in high yields with high enantioselectivity. The reaction was realized by use of (triisopropylsilyl)acetylene combined with (R)-DTBM-segphos as a chiral phosphine ligand, where the sterically bulky substituents on the silicon and phosphorus atoms suppress the alkyne dimerization.
Asymmetricconjugatealkynylation of α,β-unsaturated ketones with (triisopropylsilyl)ethynylsilanols giving β-alkynylketones took place in high yields with high enantioselectivity in the presence of chiral rhodium catalysts.