A chiral ligand-mediated asymmetric addition of a lithium BHA ester enolate to an aldehyde.
The asymmetric reaction of a lithium enolate generated from a BHA (2, 6-di-tert-buty-4-methoxyphenyl) propanoate was allowed to react with benzaldehyde in the presence of a diether-type chiral ligand affording the corresponding anti-aldol product in a moderate enantioselectivity. A tetradentate ligand induced better enantioselectivity albeit relative loss of anti-selectivity. A variation of lithiating amide agent affected the selectivity, indicating involvement of an amine as a component of the mixed aggregate. Absolute configuration of some of the aldol products was determined by standard transformations.
Faculty of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan.
Yumiko
Y
Nomura
Mayu
M
Iguchi
Hirohisa
H
Doi
Kiyoshi
K
Tomioka
D000447:Aldehydes / Q000737:chemistry*; D002083:Butylated Hydroxyanisole / Q000031:analogs & derivatives* / Q000737:chemistry; D004952:Esters; D008024:Ligands; D018020:Lithium Compounds / Q000737:chemistry*; D008968:Molecular Conformation
D000447:Aldehydes; D004952:Esters; D008024:Ligands; D018020:Lithium Compounds; D002083:Butylated Hydroxyanisole