212831-40-8Relevant articles and documents
I2-Catalyzed C-O Bond Formation and Dehydrogenation: Facile Synthesis of Oxazolines and Oxazoles Controlled by Bases
Gao, Wen-Chao,Hu, Fei,Huo, Yu-Ming,Chang, Hong-Hong,Li, Xing,Wei, Wen-Long
supporting information, p. 3914 - 3917 (2015/08/18)
A general method for the synthesis of oxazolines and oxazoles was developed through I2-catalyzed C-O bond formation and dehydrogenation with the same oxidant, TBHP. By simply tuning reaction bases, either oxazolines or oxazoles were selectively
Enantioselective synthesis of optically pure β-amino ketones and γ-aryl amines by Rh-catalyzed asymmetric hydrogenation
Geng, Huiling,Huang, Kexuan,Sun, Tian,Li, Wei,Zhang, Xiaowei,Zhou, Le,Wu, Wenjun,Zhang, Xumu
, p. 332 - 334 (2011/03/19)
A series of optically pure β-amino ketones have been synthesized in high enantioselectivities (ee > 99%) by Rh-DuanPhos-catalyzed asymmetric hydrogenation of readily prepared β-keto enamides. Further reduction of these β-amino ketones with hydrogen and Pd/C leads to the formation of a variety of protected enantiomerically pure γ-aryl amines (ee > 99%), which are key building blocks in many bioactive molecules.
Evidence That Protons Can Be the Active Catalysts in Lewis Acid Mediated Hetero-Michael Addition Reactions
Wabnitz, Tobias C.,Yu, Jin-Quan,Spencer, Jonathan B.
, p. 484 - 493 (2007/10/03)
The mechanism of Lewis acid catalysed hetero-Michael addition reactions of weakly basic nucleophiles to α,β-unsaturated ketones was investigated. Protons, rather than metal ions, were identified as the active catalysts. Other mechanisms have been ruled out by analyses of side products and of stoichiometric enone-catalyst mixtures and by the use of radical inhibitors. No evidence for the involvement of π-olefin-metal complexes or for carbonyl-metal-ion interactions was obtained. The reactions did not proceed in the presence of the non-coordinating base 2,6-di-tert-butylpyridine. An excellent correlation of catalytic activities with cation hydrolysis constants was obtained. Different reactivities of mono- and dicarbonyl substrates have been rationalised. A 1H NMR probe for the assessment of proton generation was established and Lewis acids have been classified according to their propensity to hydrolyse in organic solvents. Bronsted acid-catalysed conjugate addition reactions of nitrogen, oxygen, sulfur and carbon nucleophiles are developed and implications for asymmetric Lewis acid catalysis are discussed.
