Cover Picture Asymmetric Intramolecular Crossed-Benzoin Reactions by N-Heterocyclic Carbene Catalysis (Angew. Chem. Int. Ed. 92006)код для вставкиСкачать
Cover Picture Dieter Enders,* Oliver Niemeier, and Tim Balensiefer Enantioselective intramolecular crossed-benzoin reactions can be effected by using chiral N-heterocyclic carbene catalysts. The tetracyclic chiral carbene catalyst shown in the cover picture enables the reaction to proceed with formation of only one enantiomer of the a-hydroxy-substituted tetralones. D. Enders and co-workers disclose the development of the quaternary stereocenters in the organocatalytic reaction in their Communication on page 1463 ff. DNA Structures The local conformation in DNA governs the abstraction of hydrogen through uracil-5yl radicals. How this principle is used to analyze DNA structures is shown by H. Sugiyama and Y. Xu in their Minireview on page 1354 ff. Macrocycles In their Review on page 1364 ff., S. E. Gibson and C. Lecci take a closer look at amino acid derived macrocycles. How advanced is their synthesis? What are the applications of these compounds? Liquid Crystals The photoresponsive behavior of liquid-crystalline elastomer films with different types of mesogen alignment is discussed by T. Ikeda and co-workers in their Communication on page 1378 ff.