A concise approach to the synthesis of the unique N-mannosyl D-β-hydroxyenduracididine moiety in the mannopeptimycin series of natural products

摘要

The asymmetric synthesis of the orthogonally protected N-mannosyl D-β-hydroxyenduracididine (N-Man-D-βhEnd) is described, starting from enantiopure silylated (S)-serinol. The key steps are: (ⅰ) glyco-sylamine formation between protected serinol and a benzylated D-mannose; (ⅱ) guanidinylation; and (ⅲ) cyclic guanidine formation. This synthesis constitutes a breakthrough in our studies towards a total synthesis of mannopeptimycin and should also allow for other studies in the field of mannopeptimycin research, including the synthesis of derivatives.