59697-86-8Relevant academic research and scientific papers
Regio- and stereoselective route to tetrasubstituted olefins by the palladium-catalyzed three-component coupling of aryl iodides, internal alkynes, and arylboronic acids
Zhou, Chengxiang,Larock, Richard C.
, p. 3765 - 3777 (2005)
The Pd-catalyzed three-component coupling of readily available aryl iodides, internal alkynes, and arylboronic acids provides a convenient, one-step, regio- and stereoselective route to tetrasubstituted olefins in good to excellent yields, although electron-poor aryl iodides and dialkylalkynes normally afford only low yields under our standard reaction conditions. The proper combination of substrates and reaction conditions is important for high yields. The presence of water generally substantially increases the yields of the desired tetrasubstituted olefins. The reaction involves cis-addition of the aryl group from the aryl iodide to the less hindered or more electron-rich end of the alkyne, while the aryl group from the arylboronic acid adds to the other end. A modified, room-temperature procedure has also been successfully developed, which works very well for some substrates. Tamoxifen and its derivatives are synthesized in a concise, regio- and stereoselective manner by applying our synthetic protocol.
Palladium(0)-Catalyzed Coupling Reaction of Lithium (α-Carbalkoxyvinyl)cuprates with Organic Halides
Tsuda, Tetsuo,Yoshida, Tsutomu,Saegusa, Takeo
, p. 607 - 610 (2007/10/02)
The palladium(0)-catalyzed coupling reaction of lithium (α-carbalkoxyvinyl)(dicyclohexylamido)cuprates and organic halides such as aryl, vinyl, and benzyl halides was investigated.The lithium (α-carbalkoxyvinyl)dicyclohexylamido)cuprates were generated by conjugate addition of organo(dicyclohexylamido)cuprates to α,β-acetylenic esters.The coupling reaction using a Pd(PPh3)4 catalyst proceeded at room temperature to give synthetically useful α,β-substituted acrylates in good yields.The coupling reaction of the (α-carbalkoxyvinyl)(dicyclohexylamido)cuprate derived from a β-unsubstituted α,β-acetylenic ester took place stereoselectively to give an (E)-α,β-substituted acrylate derivative.In the vinyl halide reaction, the stereochemistry of the vinyl halide component is retained in the coupling product.The use of the dicyclohexylamido group as a nontransferable ligand is important.Thus, in the reaction using an (α-carbalkoxyvinyl)(1-hexynyl)cuprate complex, a nonselective coupling involving the 1-hexynyl group took place.
AN INTERPRETATION OF THE SUBSTITUENT EFFECT IN THE BLAISE REARRANGEMENT IN TERMS OF PI-ORBITALS
Abe, Yukio,Suehiro, Tadashi
, p. 389 - 392 (2007/10/02)
The migratory aptitude of the substituent groups in the Blaise rearrangement can be explained in terms of the pi-electronic properties of the groups in the highest occupied molecular orbitals.The rates of the rearrangement reaction with relation to the substituent groups were also rationally understood based on the energy levels of the molecular orbitals.
