3‐diynes is described. Key for the success of this novel transformation is the utilization of an advanced palladium catalyst system with the specific ligand Neolephos. The synthetic value of this general approach to synthetically useful α‐alkynyl‐α, β‐unsaturated amides is showcased by diversification of several structurally complex molecules and marketed drugs. Control experiments and density‐functional
1'-binaphthalene (Neolephos), which permits the palladium-catalyzed selective carbonylation under mild conditions, providing a general preparation of functionalized 1,3-enynes in good-to-high yields with excellent chemoselectivities. Synthetic applications that showcase the possibilities of this novel methodology include an efficient one-potsynthesis of 4-aryl-4H-pyrans as well as the rapid construction of various
Copper-catalyzed carbon–carbon bond cleavage of primary propargyl alcohols: β-carbon elimination of hemiaminal intermediates
作者:Ye-Won Kang、Yu Jin Cho、Kwang-Youn Ko、Hye-Young Jang
DOI:10.1039/c5cy00783f
日期:——
The copper-catalyzed cleavage of carbon–carbon bonds in primary propargyl alcohols under oxygen was investigated. This process involves the formation and fragmentation of hemiaminals from aldehydes (oxidized alcohols) and amines. This reaction mechanism was supported by the formation of N-formyl amines and GC experimental results.
We developed a technique mediated by visible light for the aerobic homocoupling of terminal alkynes to synthesize 1,3-conjugated diynes using a copper(I) chloride catalyst at room temperature. Compared with previously reported thermal processes, this photochemical method is simple, uses only mild reaction conditions, produces high yields and works well for substrates with electron-withdrawing groups
Homocoupling reaction of terminal alkynes catalyzed by a reusable cationic 2,2′-bipyridyl palladium(II)/CuI system in water
作者:Shao-Nung Chen、Wei-Yi Wu、Fu-Yu Tsai
DOI:10.1039/b815812f
日期:——
palladium(II)/CuI system was proven to be a reusable and highly efficient catalyst for the homocoupling of terminalalkynes at room temperature using water as a solvent in the presence of TBAB under aerobic conditions. For aromatic terminalalkynes, the reaction was performed either with or without I2 as an oxidant; the addition of I2 was required when aliphatic terminalalkynes were used as a substrate for the