59304-49-3Relevant articles and documents
Selective Synthesis of Z-Silyl Enol Ethers via Ni-Catalyzed Remote Functionalization of Ketones
Guven, Sinem,Kundu, Gourab,Rissanen, Kari,Schoenebeck, Franziska,Ward, Jas S.,We?els, Andrea
supporting information, p. 8375 - 8380 (2021/06/27)
We report a remote functionalization strategy, which allows the Z-selective synthesis of silyl enol ethers of (hetero)aromatic and aliphatic ketones via Ni-catalyzed chain walking from a distant olefin site. The positional selectivity is controlled by the directionality of the chain walk and is independent of thermodynamic preferences of the resulting silyl enol ether. Our mechanistic data indicate that a Ni(I) dimer is formed under these conditions, which serves as a catalyst resting state and, upon reaction with an alkyl bromide, is converted to [Ni(II)-H] as an active chain-walking/functionalization catalyst, ultimately generating a stabilized η3-bound Ni(II) enolate as the key selectivity-controlling intermediate.
Iron-catalyzed acylation-functionalization of unactivated alkenes with aldehydes
Tian, Tian,Wang, Xin,Lv, Leiyang,Li, Zhiping
supporting information, p. 14637 - 14640 (2020/12/02)
Herein, an iron-catalyzed acylation-functionalization of unactivated alkenes with aldehydes via distal group ipso-migration is reported. This strategy overcame the energy barrier and reversibility in the difunctionalization of unactivated alkenes with nuc
Kinetic resolution of aminoalkenes by asymmetric hydroamination: A mechanistic study
Reznichenko, Alexander L.,Hampel, Frank,Hultzsch, Kai C.
experimental part, p. 12819 - 12827 (2010/06/17)
The kinetic resolution of chiral aminoalkenes by hydroamination-cyclization was studied by using 3,3'-bis(triarylsilyl)-substituted binaphtholate rare-earth-metal complexes. The resolution of 1-arylaminopentenes proceeds with high efficiency and high irans-diastereoselectivity, whereas the resolution process of 1-alkylaminopentenes suffers from decreasing resolution efficiency with increasing steric demand of the aliphatic substituent. Kinetic studies of the matching and mismatching substrate-catalyst pair by using enantiopure substrates and either the (R)- or (S)-binaphtholate catalysts revealed that the difference in resolution efficiency stems from a shift of the Curtin-Hammett pre-equilibrium. Al-though 1-arylaminopentenes favor the matching substrate-catalyst complex, preference for the mismatching substrate-catalyst complex for 1-alkylaminopentenes diminishes resolution efficiency. Nevertheless, the relative cyclization rate for the two diastereomeric substrate-catalyst complexes remains in a typical range of 7-10:1. Plausible attractive π interactions between the aryl substituent and either the metal center or the aromatic system of the bis(triarylsilyl)-substituted binaphtholate ligand may explain increased sta-bility of the matching substrate-catalyst complex. Incidentally, the methoxymethyl (MOM)-substituted aminopentene 3g also exhibited a strong preference for the matching substrate-catalyst complex, possibly due to the chelating nature of the MOM substituent. The proximity of the stereocenter to the amino group in the aminoalkene substrate was crucial to achieve good kinetic resolution efficiency. The more remote β-phenyl substituent in 2-phenylpent-4-en-l-amine (5) resulted in diminished discrimination of the substrate enantiomers with respect to the relative rate of cyclization of the two substrate-catalyst complexes and a Curtin-Hammett preequilibrium close to unity.
