<i>gem</i>-Selective Cross-Dimerization and Cross-Trimerization of Alkynes with Silylacetylenes Promoted by a Rhodium-Pyridine-<i>N</i>-Heterocyclic Carbene Catalyst
作者:Ramón Azpíroz、Laura Rubio-Pérez、Ricardo Castarlenas、Jesús J. Pérez-Torrente、Luis A. Oro
DOI:10.1002/cctc.201402327
日期:2014.9
The gem‐selective cross‐dimerization and ‐trimerization of silylacetylenes with alkynes through CH activation using a rhodium(I)–pyridine–N‐heterocyclic carbene catalyst have been developed. This reaction is applied to various aliphatic or aromatic terminal alkynes, internal alkynes, and gem‐1,3‐disubsituted enynes to afford the corresponding enynes and dienynes with high regio‐ and stereoselectivities
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
使用2-(2,6-二异丙基苯基)亚氨基甲基吡啶(dipimp),1,2-双(二苯基膦基)乙烷(dppe)或1,2-双(二苯基膦基)苯(dppPh)的CoCl 2 ·6H 2 O / Zn试剂)作为配体有效地催化了甲硅烷基乙炔与内部炔烃的交叉加成反应。一些不对称内部炔烃(例如3-芳基炔丙醇)的反应在dppe或dppPh的存在下以高度区域选择性的方式进行,但在dipimp的存在下产生了近1:1的区域异构体混合物。使用1-氘代2-甲硅烷基乙炔的反应结果表明,该反应涉及甲硅烷基乙炔C–H键与钴的直接氧化加成。
Ligand-Controlled Cross-Dimerization and -Trimerization of Alkynes under Nickel Catalysis
a pyridine-based ligand efficiently proceeds to give the corresponding enyne compound with good yield. In contrast, their 1:2 cross-trimerization leading to a dienynederivative takes place selectively using a triarylphosphine ligand. The regioselective cross-dimerization of some unsymmetrical internal arylalkynes with terminal silylacetylenes is also accomplished using the pyridine ligand.
addition of bis(trimethylsilyl)acetylene to diarylacetylenes proceeds efficiently and selectively in a formal anti fashion in the presence of [Rh(OH)(cod)]2/bisphosphine and phenol as catalyst and activator, respectively, accompanied by cleavage of one of the C-Si bonds to produce the corresponding (Z)-enynes. The products can further couple with the same or a different diarylacetylene molecule to give