A Straightforward Synthesis of Polyketides via Ester Dienolate Matteson Homologation

Abstract

Application of ester dienolates as nucleophiles in Matteson homologations allows for the stereoselective synthesis of highly substituted α,β-unsaturated δ-hydroxy carboxyl acids, structural motifs widespread found in polyketide natural products. The protocol is rather flexible and permits the introduction of substituents and functionalities also at those positions which are not accessible by the commonly used aldol reaction. Therefore, this ester dienolate Matteson approach is an interesting alternative to the "classical" polyketide syntheses.

Keywords: Matteson homologation; boronic esters; enolates; natural products; polyketides.

Figure 1

Natural occurring peptide polyketide hybrids.

Scheme 1

Matteson homologation and application.

Scheme 2

Oxidation of chiral boronic esters 5.

Figure 2

Chiral boronic esters obtained by Matteson dienolate homologation.

Scheme 3

Synthesis of the polyketide fragment 11 of epi‐lagunamide A.