1333226-40-6Relevant articles and documents
Nanoporous gold catalyst for highly selective semihydrogenation of alkynes: Remarkable effect of amine additives
Yan, Mei,Jin, Tienan,Ishikawa, Yoshifumi,Fujita, Takeshi,Chen, Lu-Yang,Asao, Naoki,Chen, Ming-Wei,Yamamoto, Yoshinori,Minato, Taketoshi,Bao, Ming
, p. 17536 - 17542,7 (2012)
We report for the first time the highly selective semihydrogenation of alkynes using the unsupported nanoporous gold (AuNPore) as a catalyst and organosilanes with water as a hydrogen source. Under the optimized reaction conditions, the present semihydrogenation of various terminal- and internal-alkynes affords the corresponding alkenes in high chemical yields and excellent Z-selectivity without any over-reduced alkanes. The use of DMF as solvent, which generates amines in situ, or pyridine as an additive is crucial to suppress the association of hydrogen atoms on AuNPore to form H2 gas, which is unable to reduce alkynes on the unsupported gold catalysts. The AuNPore catalyst can be readily recovered and reused without any loss of catalytic activity. In addition, the SEM and TEM characterization of nanoporosity show that the AuNPore catalyst has a bicontinuous 3D structure and a high density of atomic steps and kinks on ligament surfaces, which should be one of the important origins of catalytic activity.
Copper(I)-catalyzed regio- and stereoselective intramolecular alkylboration of propargyl ethers and amines
Iwamoto, Hiroaki,Ozawa, Yu,Kubota, Koji,Ito, Hajime
, p. 10563 - 10573 (2018/05/31)
The copper(I)-catalyzed regio- and stereoselective intramolecular alkylation of propargyl ethers and amines bearing an alkyl electrophilic moiety has been developed. The reaction showed high functional group tolerance and gave highly functionalized alkenylboronates bearing heterocyclic rings, which are versatile synthetic intermediates in organic chemistry. The borylation products can be transformed into multisubstituted alkenes through stereospecific transformations. Mechanistic studies showed that the chemo- and stereoselectivity of copper(I)-catalyzed borylation depends on the type of leaving group. Density functional theory calculations suggested that the regioselectivity of the borylcupration of the alkyne is controlled by the electronic effect of the oxygen atom of the propargyl ether in combination with the steric congestion between the boryl group and the substituent at the propargylic position.
Cross-coupling of grignard reagents with sulfonyl-activated sp3 carbon-nitrogen bonds
Li, Man-Bo,Tang, Xiang-Ling,Tian, Shi-Kai
supporting information; experimental part, p. 1980 - 1984 (2011/10/12)
Sulfonyl-activated sp3 carbon-nitrogen bonds have been found to be cleaved by Grignard reagents in the presence of 5 mol% of copper(I) iodide (CuI). Significantly, a broad range of sulfonyl-activated benzylic, allylic, and propargylic amines smoothly undergo the cross-coupling reaction with Grignard reagents to afford structurally diverse coupling products in good to excellent yields and with high chemo-, regio-, and stereoselectivity. Moreover, an S N2 mechanism has been demonstrated to be involved in the cross-coupling reaction that allows the asymmetric synthesis of chiral hydrocarbons from optically active α-branched amine derivatives. Copyright
