Copper-Catalyzed Asymmetric Conjugate Addition of Trialkylaluminium Reagents to Trisubstituted Enones: Construction of Chiral Quaternary Centers
作者:Magali Vuagnoux-d'Augustin、Alexandre Alexakis
DOI:10.1002/chem.200701001
日期:2007.11.26
vinylalane species undergo enantioselective conjugateaddition to a wide range of 2- or 3-substituted enones (cyclopent-2-enones, cyclohex-2-enones, 3-methyl cyclohept-2-enone) in the presence of catalytic amount of copper salt (copper thiophene carboxylate, [Cu(CH3CN)4]BF4 or [CuOTf]2C6H6) and tropos-phosphoramidite-based ligand. Thus, chiral quaternarycenters can be built, with up to 98% ee after rigorous
Metal-free diastereoselective catalytic hydrogenations of imines using B(C6F5)3
作者:Zachariah M. Heiden、Douglas W. Stephan
DOI:10.1039/c1cc10438a
日期:——
Reductions of chiral ketimines effected under H(2) by catalytic amounts of B(C(6)F(5))(3) result in moderate to excellent diastereoselectivities. In the case of camphor and menthone derived imines, the reductions proceeded with greater than 95% diastereoselectivity.
A novel one-pot reductive amination of ketones using the combination Ti((OPr)-Pr-i)(4)/H-2/Pd-C is reported. This practical procedure does not require any solvent, and affords C-2-symmetrical secondary amines in high yields and excellent diastereoselectivities. (C) 2003 Elsevier Ltd. All rights reserved.