Preparation Of Α-amino Acids Research Articles

Factors affecting the efficiency and stereoselectivity of α-amino acid synthesis by the Petasis reaction

The use of chiral secondary amines containing only one branched substituent has been shown to give optimal yields and stereoselectivities in the preparation of α-amino acids using the Petasis reaction. While the use of chiral primary amines generally gives products in low to moderate diastereoselectivity, chiral secondary amines generally give products in >95:5 diastereoselectivity. Additionally, the use of amines with two chiral (and by definition, branched) N-alkyl substituents results in significantly reduced yields with respect to to secondary amines with one or no branched N-alkyl substituents.

N–H insertion reactions of rhodium carbenoids. Part 1. Preparation of α-amino acid and α-aminophosphonic acid derivatives

Rhodium(II) acetate-catalysed decomposition of diazophenylacetates 1 and 3 in the presence of a range of N–H compounds results in an N–H insertion reaction of the intermediate carbenoids and formation of N-substituted phenylglycine derivatives 2 and 4. The corresponding reactions of dimethyl α-diazobenzylphosphonate 5 constitute a simple route to aminophosphonates 6.

Synthesis of a chiral nickel(II) complex of an electrophilic glycinate, and its use for asymmetric preparation of α-amino acids

A chiral NiII complex of a Schiff's base derived from (S)-o-[(benzylpropyl)amino]benzophenone and α-bromoglycine has been obtained and its stereoselective reaction with nucleophiles studied; the synthesis of aspartic acid with 80% optical purity is described.