Recent developments in the stereoselective synthesis of α-aminoacids

Organozinc mediated reactions

Synthetic Preparation of N-Methyl-α-amino Acids

Begehrte Bausteine fur die Synthese von Wirk- oder Naturstoffen sind Mannich-Basen und deren Derivate. Moderne Varianten der Mannich-Reaktion, die die Bandbreite der klassischen intermolekularen Reaktion deutlich erweitern und eine effektive Kontrolle der Regio- und Stereoselektivitat ermoglichen, sind daher Gegenstand intensiver Forschung. Intramolekulare Reaktionen, insbesondere als Teil von Dominoreaktionssequenzen, fuhren haufig verbluffend einfach und elegant zu komplexen Zielverbindungen.

Moderne Varianten der Mannich‐Reaktion

Full details are provided for an exceedingly practical method to synthesize d- and l-α-amino acids, N-protected α-amino acids, and N-methyl-α-amino acids, employing as a key step the asymmetric alkylation of pseudoephedrine glycinamide (1) or pseudoephedrine sarcosinamide (2). Practical procedures for the synthesis of 1 and 2 from pseudoephedrine and glycine methyl ester or sarcosine methyl ester, respectively, are presented. Optimum protocols for the enolization and subsequent alkylation of 1 and 2 are described. Alkylation reactions of 1 and 2 are found to be quite efficient with a wide range of alkyl halide substrates, and the products are formed with high diastereoselectivity. The products of these alkylation reactions are hydrolyzed efficiently and with little to no racemization simply by heating in water or water−dioxane mixtures. This protocol provides an exceedingly practical method for the preparation of salt-free α-amino acids of high enantiomeric purity. Alternatively, the alkylation products m...

Highly Practical Methodology for the Synthesis of d- and l-α-Amino Acids, N-Protected α-Amino Acids, and N-Methyl-α-amino Acids

A new chiral glycine-cation equivalent. Asymmetric synthesis of optically pure β-amino alcohols and α-amino esters.

Asymmetric synthesis of N-methyl-α-amino esters from a glyoxal derived chiral heterocycle

Direct derivatization of glyoxal into chiral templates providing complete discrimination between the aldehyde groups

A Convenient Access to Chiral Sulfonic Acids

Neomenthyl and trans myrtanyl sulfonic acids are obtained, free from inorganic salts, starting from the corresponding chiral alcohols.

B. Prince

Papers

A new chiral glycine-cation equivalent. Asymmetric synthesis of optically pure β-amino alcohols and α-amino esters.

Asymmetric synthesis of N-methyl-α-amino esters from a glyoxal derived chiral heterocycle

Direct derivatization of glyoxal into chiral templates providing complete discrimination between the aldehyde groups

A Convenient Access to Chiral Sulfonic Acids

A Convenient Access to Chiral Sulfonic Acids.