Asymmetric catalysis. Part 153: Metal-catalysed enantioselective α-ketol rearrangement

✍ Scribed by Henri Brunner; Henri B. Kagan; Georg Kreutzer

• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 330 KB
• Volume: 14
• Category: Article
• ISSN: 0957-4166
• DOI: 10.1016/s0957-4166(03)00433-6

✦ Synopsis

Promoted by catalytic amounts of Ni complexes tertiary a-hydroxyketones 1a, 3a-5a undergo rearrangement, forming chiral isomers 1b, 3b-5b. The best enantioselection was obtained with the model system 1-benzoylcyclopentanol 4a/2-hydroxy-2phenylcyclohexanone 4b. In a ligand screening 2-[4-(S)-tert-butyloxazolin-2-yl]pyridine gave the highest enantiomeric excess of 46% (S)-4b. The analogous isomerisation reactions of a-hydroxyimines 6a, 7a forming chiral a-aminoketones 6b, 7b were established.