Palladium- and Nickel-Catalyzed Reaction of Trimethylsilyl Cyanide with Acetylenes. Addition of Trimethylsilyl Cyanide to the Carbon-Carbon Triple Bonds
The reaction of trimethylsilyl cyanide (1) with acetylenes in the presence of a transition-metal complex was investigated.The structures of starting acetylenes and catalysts and both amounts of solvent and 1 highly affected product distributions.The PdCl2/pyridine catalyzed reaction of phenylacetylene and para-substituted phenylacetylenes with 1 resulted in the addition of 1 to the carbon-carbon triple bonds to give cyano-substituted vinylsilanes in good to high yields with high regio- and stereoselectivity.Ortho-substituted phenylacetylenes gave addition products less stereoselectively.Stereoselectivity affording Z adducts decreased in the order of para- meta- ortho-substituted phenylacetylenes.The NiCl2/DIBAH-catalyzed reaction of arylacetylenes was less stereoselective regardless of substitution patterns of arylacetylenes used.When the nickel-catalyzed reaction of arylacetylenes was run without solvent using an excess amount of 1, 5-amino-1H-pyrrole-2-carbonitriles were obtained as a single product, instead of the above simple addition products.The reaction of terminal aliphatic acetylenes with 1 also gave addition products with moderate stereoselectivity.Internal acetylenes gave complex mixtures including addition products and/or pyrrole derivatives.Diarylacetylenes afforded 5-amino-1H-pyrrole-2-carbonitriles selectively in the presence of a palladium or nickel catalyst (without solvent and an excess amount of 1).Intramolecular cyclization of a 1,6-diyne was also studied.
Palladium-catalysed Addition of trimethylsilyl Cyanide to Arylacetylenes
The reaction of arylacetylenes with trimethylsilyl cyanide (1) in the presence of a palladium complex resulted in addition of (1) across the carbon-carbon triple bond with high regio- and stereo-selectivity to give β-cyano-β-arylalkenylsilanes.
Chatani, Naoto,Hanafusa, Terukiyo
p. 838 - 839
(2007/10/02)
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