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。
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.
Asymmetric construction of quaternary stereocenters by magnesium catalysed direct amination of β-ketoesters using in situ generated nitrosocarbonyl compounds as nitrogen sources
作者:Biplab Maji、Mahiuddin Baidya、Hisashi Yamamoto
DOI:10.1039/c4sc01272k
日期:——
An oxophilic magnesium salt in combination with a chiral N,N′-dioxide ligand switches the chemoselectivity of an ambident nitrosocarbonyl species to nitrogen for the highly enantioselective α-amination of β-ketoesters.
Organocatalytic Asymmetric Direct α-Alkynylation of Cyclic β-Ketoesters
作者:Thomas B. Poulsen、Luca Bernardi、José Alemán、Jacob Overgaard、Karl Anker Jørgensen
DOI:10.1021/ja067289q
日期:2007.1.1
The first organocatalyticenantioselective direct α-alkynylation of β-ketoesters and 3-acyl oxindoles is described. It is demonstrated that activated β-halo-alkynes undergo nucleophilic acetylenic substitution catalyzed by chiral phase-transfer compounds to afford the alkynylated products in high yields and excellent enantioselectivities. The potential of the reaction is first demonstrated for various