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Addition of Chiral Glycine, Methionine, and Vinylglycine Enolate Derivatives to Aldehydes and Ketones in the Preparation of Enantiomerically Pure α‐Amino‐β‐Hydroxy Acids
Author(s) -
Seebach Dieter,
Juaristi Eusebio,
Miller David D.,
Schickli Christof,
Weber Theodor
Publication year - 1987
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19870700129
Subject(s) - chemistry , amino acid , glycine , enantiomer , steric effects , hydrolysis , serine , methionine , stereochemistry , enantiomeric excess , organic chemistry , enantioselective synthesis , catalysis , enzyme , biochemistry
Chiral enolates of imidazolidinones and oxazolidinones from the title amino acids react with carbonyl compounds to afford the corresponding alcohols in excellent yields (see Scheme 5 ). Furthermore, the addition to aldehydes proceeds with high diastereoselectivity to give, after acid hydrolysis, threo ‐α‐amino‐β‐hydroxy acids of high enantiomeric purity. Some of the threo ‐α‐amino‐β‐hydroxy acids prepared in this work are the proteinogenic ( S )‐threonine ( 26 ), the naturally occurring ( S )‐3‐phenylserine ( 28 ), and ( S )‐3‐hydroxyleucine ( 27 ) as well as the unnatural ( S )‐4,4,4‐trifluorothreonine ( 30 ) and ( S )‐3‐(4‐pyridyl)serine ( 31 ). The N ‐methylamide of (2 S ,3 R ,4 R ,6 E )‐3‐hydroxy‐4‐methyl‐2‐(methylamino)‐6‐octenoic acid ( 32 ), the unique amino acid in the immunosuppressive cyclosporine, was prepared by the new method. This report presents also information suggesting that both steric and stereoelectronic effects are responsible for the good stereoselectivities observed.