Wolfgang Mägerlein

A More Efficient Catalyst for the Carbonylation of Chloroarenes

The right ligand enables the efficient carbonylation of unactivated chloroarenes. A general synthesis of benzoic acid derivatives is possible with the palladium-ferrocenylphosphane catalysts.

Total Synthesis of Colombiasin A

Colombian corals of the species Pseudopterogorgia elisabethae produce the title compound, colombiasin A (1). This structurally novel, biologically active tetracyclic compound has now been synthesized for the first time in racemic form. Preliminary studies toward the asymmetric total synthesis of both enantiomers indicate that the determination of the absolute stereochemistry can be expected soon.

Development of new palladium catalysts for the alkoxycarbonylation of aryl chlorides

Abstract The alkoxycarbonylation of different aryl chlorides was studied. Studies of the butoxycarbonylation of 4-chlorobenzotrifluoride and chlorobenzene using chelating ferrocenylphosphines reveal the advantages of these ligands compared to the well-known tricyclohexylphosphine (PCy3). (1-{2-(Dicyclohexylphosphino)ferrocenyl}ethyldicyclohexylphosphine (4) was shown to give the most active palladium catalyst system. The usefulness of this catalyst is demonstrated in the alkoxycarbonylation of various aryl chlorides. Optimized carbonylation conditions were realized by a statistical design of three critical reaction parameters.

Total Synthesis of Colombiasin A and Determination of Its Absolute Configuration

The total synthesis of the recently reported marine natural product colombiasin A (1) and determination of its absolute configuration are reported. Two Diels-Alder cycloadditions and a palladium-catalyzed rearrangement are employed as key reactions to construct the tetracyclic framework of the target molecule. The enantioselective synthesis of colombiasin A utilizes Mikamis [(S)-BINOL-TiCl2] catalyst to asymmetrically introduce the first chiral center during the initial Diels-Alder reaction and, in conjunction with X-ray crystallographic analysis of a bromine containing derivative, led to the assignment of the absolute configuration of the natural product.