Catalytic, enantioselective alkylation of alpha-imino esters: the synthesis of nonnatural alpha-amino acid derivatives.
Methodology for the practical synthesis of nonnatural amino acids has been developed through the catalytic, asymmetric alkylation of alpha-imino esters and N,O-acetals by enol silanes, ketene acetals, alkenes, and allylsilanes using chiral transition metal-phosphine complexes as catalysts (1-5 mol %). The alkylation products, which are prepared with high enantioselectivity (up to 99% ee) and diastereoselectivity (up to 25:1/anti:syn), are protected nonnatural amino acids that represent potential precursors to natural products and pharmaceuticals. A kinetic analysis of the catalyzed reaction of alkenes with alpha-imino esters is presented to shed light on the mechanism of this reaction.
Ferraris
Dana
D
Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA.
Young
Brandon
B
Cox
Christopher
C
Dudding
Travis
T
Drury
William J
WJ
Ryzhkov
Lev
L
Taggi
Andrew E
AE
Lectka
Thomas
T
D000080:Acetals / Q000737:chemistry; D000478:Alkylation; D000596:Amino Acids / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D004952:Esters / Q000737:chemistry; D007098:Imino Acids / Q000737:chemistry*; D013237:Stereoisomerism
D000080:Acetals; D000596:Amino Acids; D004952:Esters; D007098:Imino Acids