Medium-Ring Stereocontrol in the Temporary Silicon-Tethered Ring-Closing Metathesis Approach to the Synthesis of Polyketide Fragments

¯ To whom all correspondance pertaining to the crystal structure should be sent.

Abstract

The temporary silicon-tethered ring-closing metathesis of chiral non-racemic allylic and homoallylic alcohols affords unsymmetrical Z-configured trisubstituted olefins that readily undergo stereoselective hydroboration and dihydroxylation to provide a novel approach to masked polypropionate and polyol fragments present in an array of biologically important natural products. For example, this strategy provides a convenient method for the construction of polyol fragments relevant to the secondary metabolites amphidinol 3 and lophodiol A, which have antifungal and cytotoxic activity, respectively.

Key words

medium-ring - natural products - ring-closing metathesis - stereocontrol - temporary silicon-tether

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