Cobalt-Catalyzed Cross Addition of Silylacetylenes to Internal Alkynes

• Published in: Journal of organic chemistry Vol. 78; no. 8; pp. 3583 - 3591
• Main Authors: Sakurada, Tetsuya, Sugiyama, Yu-ki, Okamoto, Sentaro
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 19.04.2013; Amer Chemical Soc
• Subjects: Alkynes - chemistry; Benzene Derivatives - chemistry; Catalysis; Chemistry; Chemistry, Organic; Cobalt - chemistry; Hydrogen Bonding; Indicators and Reagents - chemistry; Ligands; Molecular Structure; Organophosphonates - chemistry; Organosilicon Compounds - chemistry; Oxidation-Reduction; Physical Sciences; Science & Technology; Stereoisomerism; H BOND ACTIVATION; ORGANIC-SYNTHESIS; UNACTIVATED ALKYNES; 2+2+2 CYCLOADDITION REACTIONS; ONE-POT SYNTHESIS; COUPLING REACTION; TERMINAL ALKYNES; HOMOGENEOUS CATALYSIS; CARBONYL-COMPOUNDS; ASYMMETRIC HYDROALKYNYLATION
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo400064b

A CoCl2·6H2O/Zn reagent using 2-(2,6-diisopropylphenyl)­iminomethylpyridine (dipimp), 1,2-bis­(diphenylphosphino)­ethane (dppe), or 1,2-bis­(diphenylphosphino)­benzene (dppPh) as a ligand effectively catalyzed the cross-addition reaction of silylacetylene to internal alkynes. The reaction of some unsymmetrical internal alkynes, such as 3-arylpropargyl alcohols, proceeded in a highly regioselective manner in the presence of dppe or dppPh but gave a nearly 1:1 mixture of regioisomers in the presence of dipimp. The results of reactions using 1-deuterated 2-silylacetylene revealed that the reaction involves a direct oxidative addition of the silylacetylenic C–H bond to cobalt.