A versatile route to L-hexoses: synthesis of L-mannose and L-altrose.

Annalisa Guaragna, Carmela Napolitano, Daniele D'Alonzo, Silvana Pedatella, Giovanni Palumbo

Index: Org. Lett. 8 , 4863-4866, (2006)

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Abstract

[reaction: see text] An efficient route for the synthesis of orthogonally protected l-sugars has been opened up, starting from the heterocyclic homologating agent 1 and 2,3-O-isopropylidene-l-glyceraldehyde (2). Our synthetic path enables the synthesis of a 2,3-unsaturated-l-pyranoside, which can be suitably functionalized to afford the desired l-hexoses. In this paper, we report the synthesis of l-manno- and l-altro-pyranosides. Moreover, this strategy may be used to prepare all eight sugars and their derivatives in either enantiomeric form.