Publications de Claudia Jana Exner

Concise Synthesis of Complicated Polypropionates through One-Pot Dissymmetrical Two-Directional Chain Elongation

Pierre Vogel, Maris Turks, Claudia Jana Exner, Freddy Fonquerne

Herein, a major breakthrough in a sulfur dioxide-mediated oxyallylation cascade reaction is reported that allows the preparation of complex long-chain polyketide fragments with more than ten stereogenic centers through a carefully designed desymmetrization ...

2011

Total Asymmetric Syntheses of beta-Hydroxy-delta-lactones via Umpolung with Sulfur Dioxide

Pierre Vogel, Maris Turks, Sylvain Claude Laclef, Claudia Jana Exner, Florent Poli

Cyclic stereotriads and stereotetrads of the beta-hydroxy-delta-lactone type, e.g. prelactones B and E, common in polyketides and polypropionates, are prepared via SO2-induced oxyallylations of enoxysilanes with (1E,3Z)-1-(1-phenylethoxy)penta-1,3-dien-3-y ...

2011

Dissymmetrical Double-Chain Elongation Approach to the Asymmetric Synthesis of Long-Chain Polypropionates

Claudia Jana Exner

Polyketides show interesting biological activities and therefore represent an important class of natural products. The necessity of their diastereo- and enantioselective synthesis led to the development of numerous methodologies. A brief overview of this t ...

EPFL2010

Synthesis of (E,Z)-1-Alkoxy-3-acyloxy-2-methylpenta-1,3-dienes via Danishefsky-Type Dienes or O-Acylation of Enones

Pierre Vogel, Maris Turks, Sylvain Claude Laclef, Claudia Jana Exner

1-Alkoxy-2-methyl-3-acyloxy-(E,E)-penta-1,3-dienes have been prepared applying among others a modified Danishefsky's general method, including chiral, racemic, and achiral derivatives. ...

2009

Umpolung with Sulfur Dioxide: Carbon-Carbon Cross-Coupling of Electron-Rich 1,3-Dienes and Alkenes; Application to the Enantioselective Synthesis of Long-Chain Polyketide Fragments

Pierre Vogel, Maris Turks, Claudia Jana Exner

At low temperature and in the presence of an acid catalyst, sulfur dioxide undergoes hetero-Diels-Alder additions with 1-oxy-1,3-dienes, giving unstable sultines, which are ionized into zwitterionic species and react as 1-oxyallylic cation intermediates (U ...

2009