A cooperative bimetallic catalyst system was applied in the catalytic asymmetric cross-dehydrogenative coupling of β-ketoesters and xanthene. Various optically active xanthene derivatives bearing a quaternary stereogenic carbon center were obtained in moderate to good yields (up to 90%) with excellent enantioselectivities (up to 99% ee). Meanwhile, a transition-state model was proposed to explain the origin of the asymmetric induction.
A highly efficient asymmetric Mannich-type reaction between α-tetralone-derived β-keto esters/amides and 1,3,5-triaryl-1,3,5-triazinanes was realized in the presence of chiral N,N′-dioxide–Ni(II) or Mg(II) complex. A variety of optically active β-amino compounds with all-carbon quaternary stereocenters were obtained in good yields with excellent enantioselectivities. A possible transition state was
Highly Enantioselective Copper-Catalyzed Electrophilic Trifluoromethylation of β-Ketoesters
作者:Qing-Hai Deng、Hubert Wadepohl、Lutz H. Gade
DOI:10.1021/ja3039773
日期:2012.7.4
Enantioselective Cu-catalyzed trifluoromethylation of β-ketoesters using commercially available trifluoromethylating reagents is reported. A number of α-CF(3) β-ketoesters are obtained with up to 99% ee. The trifluoromethylated products were then transformed diastereoselectively to α-CF(3) β-hydroxyesters with two adjacent quaternary stereocenters via a Grignard reaction.
报道了使用市售三氟甲基化试剂对 β-酮酯进行对映选择性 Cu 催化的三氟甲基化。获得了许多具有高达 99% ee 的 α-CF(3) β-酮酯。然后通过格氏反应将三氟甲基化产物非对映选择性地转化为具有两个相邻季立体中心的 α-CF(3) β-羟基酯。
Cooperative Palladium/Brønsted Acid Catalysis toward the Highly Enantioselective Allenylation of β-Keto Esters
作者:Henning J. Loui、Christoph Schneider
DOI:10.1021/acs.orglett.2c00179
日期:2022.2.25
We report the first enantioselective allenylation of Pd enolates enabled by cooperative Pd/Brønsted acid catalysis employing β-keto esters and propargyl alcohols. The enantioselectivity originates solely from an in-situ-generated chiral metal enolate in an open transition state with no additional binding of the propargyl component to the catalyst. Thus a broad substrate scope was established, furnishing
Copper-Boxmi Complexes as Highly Enantioselective Catalysts for Electrophilic Trifluoromethylthiolations
作者:Qing-Hai Deng、Christoph Rettenmeier、Hubert Wadepohl、Lutz H. Gade
DOI:10.1002/chem.201303641
日期:2014.1.3
The enantioselectivetrifluoromethylthiolation of β‐ketoesters using chiral copper–boxmicomplexes as catalysts is reported. A number of α‐SCF3‐substituted β‐ketoesters have been obtained with up to >99 % enantiomeric excess (ee), and the trifluoromethylthiolated products were then transformed diastereoselectively to α‐SCF3‐β‐hydroxyesters with two adjacent quaternary stereocenters.