228858-52-4Relevant academic research and scientific papers
Enantioselective synthesis of β-hydroxy-α-amino acid esters by aldol coupling using a chiral quaternary ammonium salt as catalyst
Horikawa, Manabu,Busch-Petersen, Jakob,Corey
, p. 3843 - 3846 (1999)
A variety of chiral β-hydroxy-α-amino acids and derivatives thereof can be synthesized enantioselectively using the aldol reaction of an aldehyde, the gIycinate 1 and the cinchonidinederived catalyst 2, as indicated in Schemes 1 and 2 and Table 1.
Development of highly diastereo- and enantioselective direct asymmetric aldol reaction of a glycinate Schiff base with aldehydes catalyzed by chiral quaternary ammonium salts
Ooi, Takashi,Kameda, Minoru,Taniguchi, Mika,Maruoka, Keiji
, p. 9685 - 9694 (2004)
A highly efficient direct asymmetric aldol reaction of a glycinate Schiff base with aldehydes has been achieved under mild organic/aqueous biphasic conditions with excellent stereochemical control, using chiral quaternary ammonium salt 1b as a phase-transfer catalyst. The initially developed reaction conditions, using 2 equiv of aqueous base (1% NaOH (aq)), exhibited inexplicably limited general applicability in terms of aldehyde acceptors. The mechanistic investigation revealed the intervention of an unfavorable yet inevitable retro aldol process involving the chiral catalyst. On the basis of this information, a reliable procedure has been established by use of a catalytic amount of 1% NaOH (aq) and ammonium chloride, which tolerates a wide range of aldehydes to afford the corresponding anti-β-hydroxy-α-amino esters almost exclusively in an essentially optically pure form.
