Thomas Oeser

Gold-catalyzed synthesis of chroman, dihydrobenzofuran, dihydroindole, and tetrahydroquinoline derivatives.

Different furans containing an ynamide or alkynyl ether moiety in the side chain were prepared. The gold-catalyzed transformation of these compounds delivered dihydroindole, dihydrobenzofuran, chroman, and tetrahydroquinoline derivatives at room temperature through very fast reactions. Furthermore, the stabilizing effect of the heteroatom directly attached to the intermediate arene oxides led to highly selective reactions, even in the case of only mono-substituted furans, which is quite different from previous results obtained with non-heteroatom-substituted alkynes.

Consecutive Three-Component Synthesis of Ynones by Decarbonylative Sonogashira Coupling

Mild conditions! Decarbonylative carbonylation by consecutive glyoxylation of indoles, 7-aza-indoles, or pyrroles with oxalyl chloride and subsequent Pd/Cu-catalyzed decarbonylative alkynylation with terminal alkynes furnishes alkynones under very mild conditions. 4-(Indol-3-yl)-, 4-(7-aza-indol-3-yl)-, and 4-(pyrrol-2-yl)-2-amino pyrimidines can be readily obtained in a concise two-step synthesis starting from N-substituted indoles, 7-aza-indoles, or pyrroles (see scheme).

A novel one-pot four-component access to tetrahydro-β-carbolines by a coupling-amination-aza-annulation-Pictet–Spengler sequence (CAAPS)

The four-component coupling-amination-aza-annulation-Pictet-Spengler (CAAPS) sequence of acid chlorides 1, terminal alkynes 2, tryptamine derivatives 6, and acryloyl chloride derivatives 4 represents a facile and rapid one-pot access to tetrahydro-beta-carbolines 7 in moderate to good yields.

Crystal Engineering with Symmetrical Threefold Acceptor-Substituted Triaminobenzenes

Is it possible to identify molecular architectures that allow prediction of crystal structures? Can the factors that determine these structures be identified? To answer these questions, analogues of 1, which forms layer structures, were synthesized in which some or all of the nitro groups were replaced with sulfonyl acceptors. Surprisingly, the expected drastic change in the conformational and/or crystallographic behavior was not observed.

Phenothiazinophanes: synthesis, structure, and intramolecular electronic communication.

Ortho-phenylene, ethenylene, and ethylene-bridged phenothiazinophanes are synthesized by Suzuki coupling or McMurry dimerization and catalytic hydrogenation at ambient pressure. Intensive intramolecular electronic communication of the phenothiazinyl subunits is found according to cyclic voltammetry. In addition, the macrocycles display blue to green fluorescence with large Stokes shifts. In the solid state, the cyclophanes are arranged in unidimensional stacks. This orientation appears to be favorable for anisotropic charge transport in hole-transport materials for organic field effect transistors (OFET) applications.

Easy one-pot synthesis of new dppm-type linkers for immobilizations

New synthetic routes to symmetric and unsymmetric dppm-type chelate linkers containing the ethoxysilane group are described and the compounds were characterized also by solid-state NMR spectroscopy and X-ray structures.

New linker systems for superior immobilized catalysts

The rigid linkers E(p-C6H4PPh2)4 (E = Si, Sn) have been synthesized from the corresponding precursors E(p-C6H4Br)4 and immobilized by forming one (E = Si) or three (E = Sn) phosphonium groups that are attached to the silica support by electrostatic interactions. The remaining unquaternized phosphines are coordinated to Wilkinson-type Rh complexes. The catalyst immobilized by the rigid scaffold with three surface-bound phosphonium groups (E = Sn) displays superior catalytic activity and lifetime with respect to the hydrogenation of dodecene. This catalyst can be recycled 30 times in a batchwise manner under standardized conditions.

Spectroscopic characterization and crystal structure of the 1,2,3,4,5,6-hexahydrophenanthro[1,10,9,8-opqra]perylene

The spectroscopic characterization and the crystal structure of the 1,2,3,4,5,6-hexahydrophenanthro[1,10,9,8-opqra]perylene, which is known from the fossil record, is described.

Determination of the Electron Density Distribution in the Bonds of a Fullerene Derivative by High‐Resolution X‐Ray Structure Analysis

Bent bonds in the strained fullerene system, restricted to the [5,6] bonds, were detected by high-resolution X-ray structure analysis of the 1,2-dihydro[60]fullerene derivative 1. In addition the maxima of electron densities are higher in the [6,6] bonds than in the [5,6] bonds-an important finding with respect to the question of the extent of electron delocalization in fullerenes.

A widely applicable concept for predictable induction of preferred configuration in C3-symmetric systems

Starting from a single chiral platform a widely applicable concept to introduce the preferred configuration of octahedral and tetrahedral centres in C3-symmetric systems is described.