2000 stereochemistry

stereochemistry (general, optical resolution)O 0030

07 - 046Catalytic Enantioselective Conjugate Addition of 1,3-DicarbonylCompounds to Nitroalkenes. — The first highly enantioselectivecatalytic conjugate addition of β-ketoesters (IV) and (VII) as well as malonates(IX) to nitroolefins (V) or (X) is presented. The reaction proceeds smoothlyunder catalysis of Mg(O-Tf)2·4H2O–bis(oxazoline) (Ia) in the presence ofN-methylmorpholine (NMM) as cocatalyst. Optimization of reaction conditions,concerning solvent, presence of water and NMM, and nature of chiral ligand, ispresented. The reaction is shown to proceed with a wide variety of substitutednitrostyrenes as well as alkyl-substituted nitroolefins. Additionally, stericbulk of the ester affects rate and selectivity of the addition reaction. —(JI, JIANGUO; BARNES, DAVID M.; ZHANG, JI; KING, STEVEN A.;WITTENBERGER, STEVEN J.; MORTON, HOWARD E.; J. Am. Chem.Soc. 121 (1999) 43, 10215-10216; Process Chem. Res., Pharm. Prod. Div.,Abbott Lab., Abbott Park, IL 60064, USA; EN)

1