Non-classical C -saccharide linkage of dehydroalanine: synthesis of C -glycoamino acids and C -glycopeptides.

Herein, a non-classical C -saccharide linkage is reported via a C5 radical of pentose or C6 radical of hexose addition to Michael acceptors. C(sp 3 )-S cleaved glycosyl thianthrenium salts are developed as the glycosyl radical agents. The reaction provides an efficient toolkit to synthesize β-glycosyl substituted unnatural amino acids as well as for the late-stage C -saccharide modification of peptides.