Enantioselective Syntheses of the Alkaloids <i>cis</i>-195A (Pumiliotoxin C) and <i>trans</i>-195A Based on Multiple Applications of Asymmetric Catalysis

Short enantio- and diastereoselective syntheses of the decahydroquinoline alkaloids <i>cis</i>- (pumiliotoxin C) and <i>trans</i>-<b>195A</b> are presented. Key steps are an enantioselective iridium-catalyzed allylic amination, a Suzuki–Miyaura coupling, a catalyst-controlled copper-catalyzed 1,4-addition, and a reductive amination

Enantioselective Total Synthesis and Absolute Configuration of Apiosporic Acid

The first total synthesis of the polyketide apiosporic acid is presented. Key steps are a Julia–Kocienski olefination, a Suzuki–Miyaura cross-coupling, and an intramolecular Diels–Alder reaction. The absolute configuration of the natural product was determined

Synthesis and Biological Properties of Novel Brefeldin A Analogues

New brefeldin A (<b>1</b>) analogues were obtained by introducing a variety of substituents at C15. Most of the analogues exhibited significant biological activity. (15<i>R</i>)-Trifluoromethyl-nor-brefeldin A (<b>3</b>), (15<i>R</i>)-vinyl-nor-brefeldin A (<b>5</b>), their epimers <b>4</b> and <b>6</b> as well as (15<i>S</i>)-ethyl-nor-brefeldin A (<b>2</b>) were prepared from the key building blocks <b>12</b> or <b>24</b> by Julia–Kocienski olefination with tetrazolyl sulfones and subsequent macrolactonization. The vinyl derivative <b>5</b> allowed analogues to be synthesized by hydroboration and Suzuki–Miyaura coupling. The following biological properties were assessed: (a) inhibition of cell growth of human cancer cells (NCI), (b) induction of morphological changes of the Golgi apparatus of plant and mammalian cells, and (c) influence on the replication of the enterovirus CVB3. Furthermore, conformational aspects were studied by X-ray crystal structure analysis and molecular mechanics calculations, including docking of the analogues into the brefeldin A binding site of an Arf1/Sec7-complex