A highly efficient α-hydroxylation of β-ketoesters catalyzed by cupreidine in the presence of cumyl hydroperoxide (CHP) was achieved. The reaction was applied to a wide variety of β-ketoesters to give products in high yields (up to 95%) with excellent enantioselectivities (up to 97% ee). The reaction had been successfully scaled up to a gram quantity and (S)-5-chloro-2-hydroxy-1-oxo-2,3-dihydro-
Organocatalytic Enantioselective 1,3-Dipolar Cycloadditions between Seyferth–Gilbert Reagent and Isatylidene Malononitriles: Synthesis of Chiral Spiro-phosphonylpyrazoline-oxindoles
作者:Taiping Du、Fei Du、Yanqiang Ning、Yungui Peng
DOI:10.1021/acs.orglett.5b00311
日期:2015.3.6
A new method has been developed for the catalytic enantioselective 1,3-dipolar cycloaddition of the Seyferth–Gilbert reagent (SGR) to isatylidene malononitriles using a cinchonaalkaloidderivative as a catalyst. This method allowed for the synthesis of a series of chiral spiro-phosphonylpyrazoline-oxindoles in good yields with excellent enantioselectivities. The synthetic utility of this method was
Direct Catalytic Asymmetric Synthesis of Trifluoromethylated γ-Amino Esters/Lactones via Umpolung Strategy
作者:Bin Hu、Li Deng
DOI:10.1021/acs.joc.8b02893
日期:2019.1.18
Enabled by the discovery of new cinchonium salts and coadditives, a direct and efficient asymmetric access to trifluoromethylated γ-amino esters/lactones has been realized through the enantioselective and diastereoselective umpolung reaction of trifluoromethyl imines with acrylates or α,β-unsaturated lactones as carbon electrophiles. At 0.5-5.0 mol % catalyst loadings, the newly developed catalytic
Enantioselective Sulfonimidamide Acylation via a Cinchona Alkaloid-Catalyzed Desymmetrization: Scope, Data Science, and Mechanistic Investigation
作者:Brittany C. Haas、Ngiap-Kie Lim、Janis Jermaks、Eden Gaster、Melody C. Guo、Thomas C. Malig、Jacob Werth、Haiming Zhang、F. Dean Toste、Francis Gosselin、Scott J. Miller、Matthew S. Sigman
DOI:10.1021/jacs.4c00374
日期:2024.3.27
cinchona-phosphinate catalyst. The desired products are formed in excellent yield and enantioselectivity with no observed bis-acylation. A data-science-driven approach to substrate scope evaluation was coupled to high throughput experimentation (HTE) to facilitate statistical modeling in order to inform mechanistic studies. Reaction kinetics, catalyst structural studies, and density functional theory