Concise synthesis of 3-deoxy-D-manno-oct-2-ulosonic acid (KDO) as a protected

A. Kuboki, T. Tajimi, Y. Tokuda, D.-i. Kato, T. Sugai and S. Ohira

A concise synthesis of KDO as the suitably protected form from 2,3:5,6-di-O-isopropylidene-α-D-mannofuranose was achieved in five steps (overall 65% yield). The key step is the efficient transformation of readily available α,β-unsaturated ester to α-oxocarboxylic acid ester. The newly β-elimination of the corresponding diol cyclic sulfite and the in situ trap (DBU/TMSCl) into enol silyl ether was developed to give the tautomeric equivalent of α-oxocarboxylic acid ester. The deprotection of acid labile TMS ether provided the desired product.

Tetrahedron Lett.

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