reducing alkenes bearing metal-coordinating groups. In the present system, selectivity was pressure-dependent: In most cases, a decrease in the H2 pressure to 3 bar resulted in an increase in enantioselectivity. Moreover, the process can be carried out in environmentally friendly solvents, such as methanol and ethyl acetate, with no loss of selectivity.
MaxPHOX-Ir 催化剂系统为 α-和 β-四氢萘酮衍生的环状烯酰胺的还原提供了迄今为止报道的最高选择性。该结果表明铱催化剂也能有效还原带有金属配位基团的烯烃。在本系统中,选择性取决于压力:在大多数情况下,氢气压力降低至 3 bar 会导致对映选择性增加。此外,该过程可以在甲醇和乙酸乙酯等环保溶剂中进行,而不会损失选择性。
P-Stereogenic and Non-P-Stereogenic Ir–MaxPHOX in the Asymmetric Hydrogenation of <i>N</i>-Aryl Imines. Isolation and X-ray Analysis of Imine Iridacycles
A small library of Ir–MaxPHOX catalysts has been applied to the asymmetrichydrogenation of N-aryl imines. A structure–activity analysis of the three-chiral-center MaxPHOX ligand has been performed. Using complex 1b, the hydrogenation of N-aryl imines took place with up to 96% enantiomeric excess at atmospheric pressure of hydrogen and low temperature. The impact of the stereochemical information at
Synthesis and activity of an HIV-1 Protease inhibitor containing a contiguous (E)-olefin-hydroxyethylene peptide mimetic
作者:Richard M. Keenan、Daniel F. Eppley、Thaddeus A. Tomaszek
DOI:10.1016/0040-4039(94)02416-9
日期:1995.2
To investigate the contribution of a key amide bond to HIV Protease inhibition, we designed and synthesized a novel (E)-olefin hydroxyethylene analog. The stereoselective synthesis of this interesting homoallylic alcohol structural motif as well as its biological activity are discussed.
the presence of a cyclic hydrogen-bond network in the solid state which accounts for an increased melting point and stability. Dialkylammonium phosphinite boranes are convenient precursors of the chiral tert-butylmethylphosphine fragment. Compound 6 can be used directly in SN[email protected] reactions with various nucleophiles to yield valuable P-stereogenic intermediates and ligands.