Synthesis of Multiantennary Complex Type N ‐Glycans by Use of Modular Building Blocks

A modular set of oligosaccharide building blocks was developed for the synthesis of multiantennary N ‐glycans of the complex type, which are commonly found on glycoproteins. The donor building blocks were laid out for the elongation of a core trisaccharide acceptor (β‐mannosyl chitobiose) conveniently protected with a single benzylidene moiety at the β‐mannoside. Through two consecutive regio‐ and stereoselective couplings the donors gave N ‐glycans with three to five antennae in high yields. Due to the consistent protection group pattern of the donors the deprotection of the final products can be performed by using a general reaction sequence.