The synthesis of oligomers containing alternating C-glycosyl α-amino acids and proteinogenic α-amino acids

C-Glycosyl amino acids are a group of C-glycosides in which a carbohydrate molecule is attached to the side chain or backbone of the amino acid via a C-C bond. Despite the numerous methods that have been developed for their synthesis, the C-glycosyl alpha-amino acids and their oligomers are relatively unexplored. In this work, we presented a protocol for the synthesis of oligomers containing alternating C-glycosyl alpha-amino acids and proteinogenic alpha-amino acids. The methodology is based on the modification of alpha-acyloxyamides obtained from the Passerini reaction using alpha-d-galactopyranose- and alpha-l-sorbofuranose-derived aldehydes as C-glycosyl donors. The protocol enabled the synthesis of homo- and heterochiral tetramers, and homo- and heterovalent tetramers in very good yields.