In this work we present the successful application of functionalizing Pt nanoparticles (NPs) with hydrophilic organic ligands as a strategy for enhancing their catalytic activity and selectivity. In the first step, Pt NPs were prepared by a colloidal approach and subsequently functionalized in a separate synthesis step with L-proline (PRO). The functionalized NPs were supported onto Al2O3 and investigated as heterogeneous catalysts for the selective hydrogenation of acetophenone. Whereas significant amounts of side products are formed by supported, "unprotected" (ligand-free) NPs, the PRO-functionalized Pt NPs are highly chemoselective even at 100% conversion. Experiments under kinetically controlled conditions reveal that this high chemoselectivity is not accompanied by a loss of catalytic activity. In contrast, an enhanced rate toward the desired product was found for PRO-Pt in comparison to the "unprotected" Pt NPs. This finding demonstrates that the use of ligands in heterogeneous catalysis allows for simultaneous enhancements of activity and selectivity.

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Stereoselective control on amino acid functionalized supported Pt nanoparticles by means of dispersion interactions.

Dedicated to Professor Gerhard Spiteller on the occasion of his 85th birthday.The first total synthesis of makaluvamine O and batzelline D, pyrroloquinoline alkaloids isolated from marine sponges, are described. Key steps in the biomimetic synthesis are an intramolecular Michael addition leading to the pyrrolo[4,3,2-de]quinoline core and the following selective halogenation at C-6 position with NBS/NCS. Moreover, the related marine alkaloids damirone C, makaluvone and batzelline C were synthesised via this approach.

Here we report the first total synthesis of the fungal alkaloids mycenarubin A, sanguinolentaquinone and mycenaflavin B. The pyrroloquinoline alkaloid mycenarubin A was obtained in 10 steps (21 % total yield, 92 % ee) from the known key precursor 6,7‐bis(benzyloxy)indole by an asymmetric alkylation and a biomimetic ring closure as the key steps. The indolo‐6,7‐quinone sanguinolentaquinone was obtained in eight steps (28 % total yield). Mycenaflavin B was also obtained in eight steps starting from the same key precursor (total yield 15 %) by a biomimetic ring closure and an acid‐catalysed decarboxylation reaction as the key steps. The cytotoxic activities of mycenarubin A and mycenaflavin B were evaluated against mouse fibroblasts (L929) and human malignant melanoma cells (RPMI‐7951).