Efficient synthesis of enantiopure beta-amino-gamma-keto acids from l-homoserine

[reaction: see text] A variety of beta-amino-gamma-keto acids were prepared in four steps from commercially available l-homoserine. The reaction sequence is highlighted by a Ni-catalyzed Grignard addition to a N-protected derivative of l-homoserine. One of the beta-amino-gamma-keto acids was then used to create a beta-peptide trimer composed solely of beta-amino-gamma-keto acids.