Highly diastereoselective Michael addition reactions of butane-2,3-diacetal desymmetrized glycolic acid. Preparation of alpha-hydroxy-gamma-amino acid derivatives.
[reaction--see text] The butane-2,3-diacetal (BDA) desymmetrized glycolic acid building block undergoes efficient and highly diastereoselective lithium enolate Michael additions to alpha,beta-unsaturated ketones, lactones, and nitro olefins. Subsequent deprotection of these Michael adducts gives alpha-hydroxy acids in very high yield. Hydrogenation of the nitro group in some of the adducts leads to gamma-lactams, which can be easily converted into alpha-hydroxy-gamma-amino acid derivatives.
Dixon
D J
DJ
Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK. .
Ley
S V
SV
Rodríguez
F
F
D000080:Acetals; D002384:Catalysis; D007202:Indicators and Reagents; D008094:Lithium; D018020:Lithium Compounds; D009682:Magnetic Resonance Spectroscopy; D012821:Silanes
D000080:Acetals; D007202:Indicators and Reagents; D018020:Lithium Compounds; D012821:Silanes; C442342:butane-2,3-diacetal glycolic acid; D008094:Lithium; C442341:lithium hexamethyldisilazide