A highly enantioselective Friedel–Crafts alkylation of indoles with ethyltrifluoropyruvate has been developed using N,N′-dioxide-zinc(II) complexes. Both enantiomers of the desired adducts were obtained by the use of enantiomeric ligands in excellent results (up to 99% yield and 98% ee) within 0.5 h under mild conditions. On the basis of the experimental results, a proposed working model was proposed
the Friedel-Crafts (FC) reaction of indole with trifluoropyruvate with high generality, yielding the highly enantiomerically enriched FC adduct. Electron-rich indoles have high reactivity due to a dual activation mechanism showing second-order kinetics for CuII, whereas indoles with a soft substituent at C(4) proceed at a rate that is three orders of magnitude lower via a coordination mechanism, which
Asymmetric Friedel–Crafts Alkylation of Indoles with Trifluoromethyl Pyruvate Catalyzed by a Dinuclear Zinc Catalyst
作者:Yuan-Zhao Hua、Jun-Wei Chen、Hua Yang、Min-Can Wang
DOI:10.1021/acs.joc.7b02599
日期:2018.2.2
cooperative catalysis model has been reported for the asymmetric Friedel–Crafts (F–C) alkylation of indoles with trifluoromethyl pyruvates using Trost’s intramolecular dinuclear zinc complex as the catalyst. This dinuclear zinc catalyst was prepared in situ by reacting the chiral ligand (S,S)-L2b with 2 equiv of ZnEt2. A series of trifluoromethyl alcohol and indole-containing biological compounds were formed
Enantioselective inhibition of reverse transcriptase (RT) of HIV-1 by non-racemic indole-based trifluoropropanoates developed by asymmetric catalysis using recyclable organocatalysts
Herein, we report the development of efficient inhibitors of reverse transcriptase (RT) of HIV-1 based on indole-alkyl trifluoropyruvate derivatives by a TZM-bl cell assay. The inhibitory activities of the two enantiomers and the corresponding racemic mixture have been compared. TZM-bl cells exhibited strong enantioselective discrimination for the (R)-configuration, among these indole derivatives, the most active compound R-12, with a 5-NO2 substituent, gave the best result when tested in the TZM-bl cells on HIV virus type HIV-1IIIB, with an EC50 value of 0.019 μM, CC50 value of 210.697 μM and SI (selectivity index, CC50/EC50) value of 11 089, respectively. The cell test showed that, in most cases, the R-enantiomer was superior to the Rac-mixture, which was better than the corresponding S-enantiomer. The results indicated that the R-enantiomer is the most favorable configuration as an efficient HIV-1 inhibitor. Molecular modeling studies suggested a structural basis for the enantioselectivity of RT towards this class of molecules.
Indoles, and pyrroles, and furans, oh my! Chiral phosphoric acidcatalyzed Friedel–Crafts alkylation of indoles with 3,3,3‐trifluoropyruvate gave the corresponding adducts in excellent yields with high enantioselectivities. Electron‐deficient indoles, in particular, exhibited excellent enantioselectivities.