Synthesis of the Aliphatic Subunit of the Macrolide LL‐Z 1640‐2 via Vasella Ring Opening of a 6‐Iodo‐4‐deoxy‐D‐mannose

Abstract

The synthesis of the aliphatic subunit 9 of the macrolide LL-Z1640-2 (I), starting from a 4-deoxy-D-mannose derivative 2a, is described. The procedure includes the first successful application of a Vasella ring opening reaction for a 4-deoxypyranoside. Nucleophilic addition of an alkynyllithium reagent to the aldehyde 4 led to the propargylic alcohol 7, which was converted to the advanced building block 9 in two further steps.