From Polymer to Size‐Defined Oligomers: A Highly Divergent and Stereocontrolled Construction of Chondroitin Sulfate A,C, D,E, K,L, and M Oligomers from a Single Precursor: Part 2

An efficient, stereocontrolled, and highly divergent approach for the preparation of oligomers of chondroitin sulfate (CS) A, C, D, E, K, L, and M variants, starting from a single precursor easily obtained by semisynthesis from abundant natural polymer is reported for the first time. Common intermediates were designed that allowed the straightforward construction of O‐sulfonated species either on the D ‐galactosamine unit (CS‐A, ‐C, and ‐E) or on both D ‐glucuronic acid and D ‐galactosamine units (CS‐D and CS‐K, ‐L, and ‐M). This strategy represents a successful improvement and brings a definitive answer toward the synthesis of such complex molecules with numerous relevant biological functions.