Synthesis, Conformational Studies and Mannosidase Stability of a Mimic of 1,2‐Mannobioside

Dimethyl (1 S ,2 S ,4 S ,5 S )‐4‐allyloxy‐5‐(α‐mannosyloxy)cyclohexane‐1,2‐dicarboxylate ( 3) was designed as a structural mimic of α(1,2)mannobioside ( 1 ). Its synthesis and structural analysis by NMR spectroscopy and molecular modelling are described. The results show that 3 , like 1 , populates two low‐energy conformations — stacked ( S ) and extended ( E ) — that are in fast dynamic equilibrium around the glycosidic linkage. Thus, the data confirm the expectation that the pseudo‐disaccharide can be used as a structural mimic of mannobioside. The mannosidase stability of 3 was found to be significantly higher (sixfold) than that of natural mannobioside. This is a very useful feature of this mimic and is encouraging for its future development. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)