A very effective high-pressure-induced acceleration of asymmetric organocatalytic conjugate addition of nitromethane to sterically congested β,β-disubstituted β-CF3 enones has been developed. A combination of pressure (8-10 kbar) and noncovalent catalysis with low-loading of chiral tertiary amine-thioureas (0.5-3 mol %) is shown to provide very efficient access to a wide range of γ-nitroketones containing trifluoromethylated all-carbon quaternary stereogenic centers in the β-position (80-97%, 92-98% ee).

The application of high pressure (up to 9 kbar) allows for relatively fast (1-5 h) and highly enantioselective 1,4-addition of nitromethane and 2-nitropropane to chalcones at room temperature with substantial reduction of catalyst loading (0.2-1 mol% of cinchona alkaloid-based thioureas and squaramides). Various γ-nitroketones were obtained at 9 kbar with high yield and enantioselectivity (up to 98%), whereas in control experiments at atmospheric pressure usually only a small amount (<10%) of products were formed after 20 h.

The DITIPIRAM (8-propyldithieno[3,2-b:2',3'-e]pyridine-3,5-diamine)-based receptors 11 and 12 were readily synthesized, and their anion-binding properties were studied both in solution and in the solid-state. H NMR titrations revealed that receptor 12 equipped with two phenyl-urea groups preferentially binds carboxylates, even in the highly competitive DMSO-d/CDOH solvent mixture. X-ray analysis showed that receptor 12 exhibited great complementarity for benzoate, which is cooperatively bound by the means of four highly directional hydrogen bonds from the two urea groups. Comparison with the most effective acyclic receptors based on a structurally related rigid carbazole platform demonstrates that the DITIPIRAM motif provides a better suited geometry in the binding pocket, and consequently stronger anion binding.

A selective digest of linear anion receptors based on different aromatic skeletons is presented. Since the structures of anions vary from one to another, different strategies have been developed over recent years in order to bind anions efficiently and selectively. Rigidity, number of hydrogen bond donors, steric hindrance, and special preorganization of linear receptors are analyzed to shed light on the rational design of anion receptors.1 Introduction2 1,3- and 1,2-Benzene Derivatives3 1,3- and 5,7-Azulene Derivatives4 1,8-Naphthalene Derivatives5 1,8-Anthracene Derivatives6 2,6-Pyridine Derivatives7 2,5-Pyrrole Derivatives8 Diamidoarenodipyrrole Derivatives9 Carbazole Derivatives10 DITIPIRAM Derivatives11 Conclusion