Organocatalytic Asymmetric Conjugate Addition to Allenic Esters and Ketones
作者:Petteri Elsner、Luca Bernardi、Giorgio Dela Salla、Jacob Overgaard、Karl Anker Jørgensen
DOI:10.1021/ja710689c
日期:2008.4.1
having different ring sizes, ring systems, and substituents in high yields and enantioselectivities. Glycine imine derivatives also undergo the asymmetric conjugate addition to electron-deficient allenes in high yields and with enantioselectivities in the range of 60-88% ee, thus providing a rapid entry to optically active alpha-vinyl-substituted alpha-amino acid derivatives. It is shown that the enantioselectivity
The first organocatalytic âanti-Michaelâ reaction of cyclic-β-ketoesters to unsaturated double bonds is described in a highly asymmetric version leading to the synthesis of α,αâ²-disubstituted branched double bonds as optically active BaylisâHillman-like adducts.
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.
Asymmetric α-Benzoyloxylation of β-Ketocarbonyls by a Chiral Primary Amine Catalyst
作者:Dehong Wang、Changming Xu、Long Zhang、Sanzhong Luo
DOI:10.1021/ol503592n
日期:2015.2.6
The direct asymmetric α-benzoyloxylation of β-ketocarbonyls catalyzed by a chiral primary amine is described herein. This protocol demonstrates excellent enantioselectivity for a broad range of substrates, which allows convenient access to highly enantioenriched α-hydroxy-β-ketocarbonyls.