Three‐Component Staudinger‐Type Stereoselective Synthesis of C ‐Glycosyl‐β‐lactams and their Use as Precursors for C ‐Glycosyl Isoserines and Dipeptides. A Polymer‐Assisted Solution‐Phase Approach

A collection of 4‐( C ‐galactosyl)‐ and 4‐( C ‐ribosyl)‐β‐lactams featuring different substituents at C‐3 and N‐1 was prepared by combining in a one‐pot procedure a formyl C ‐glycoside, a primary amine, and a substituted acetyl chloride in the presence of base (Staudinger‐type reaction). Sulfonyl chloride and aminomethylated resins were used in sequence to remove excess of components and by‐products. Two pure C ‐glycosyl‐β‐lactams were effectively transformed into C ‐glycosyl‐ N ‐Boc‐β‐amino‐α‐hydroxy esters ( C ‐glycosyl isoserines) and a C ‐ribosyl dipeptide via base‐promoted heterocycle ring opening by methanol and L ‐phenylalanine methyl ester, respectively.