Synthesis of Glycopeptides: Selective Amino‐Deblocking of 2‐Phosphonioethoxycarbonyl‐Protected Asparagine N‐Acetylglucosamine Moieties

Models for acid- and base-sensitive glycopeptides of type (1), with N-glycosidically linked asparagine moieties, can be synthesized by employing the Peoc-protecting group (Ph3P⊕(CH2)2OCO), which can be selectively removed, e.g., with 5% HNEt2 in tBuOH. In this way, it is possible to increase the chain length with further N-Peoc amino acids.