Angewandte Chemie International Edition
© WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Cover Picture: The Catalytic Asymmetric Knoevenagel Condensation (Angew. Chem. Int. Ed. 7/2011)
The annual rings of the pictured tree represent the time gap, 116 years, between the discovery of the Knoevenagel condensation and that of the first catalytic asymmetric variant. As described by B. List et al. in their Communication on page 1707 ff., a cinchona amine catalyst promotes the reaction of α-branched aldehydes and malonates through a dynamic kinetic resolution to give alkylidene malonates with high enantioselectivity.
Also of Interest
Responsive Photonic Crystals
Responsive photonic crystals can respond to different stimuli and have manifold applications. In their Review on page 1492 ff., Y. Yin and J. Ge explain how to prepare and condition such crystals for specific purposes.
D. Armspach, D. Matt, and co-workers describe in their Communication on page 1554 ff. how attaching an unsymmetrical diphosphine to a β-cyclodextrin cavity led to it oscillating about a metal center while remaining chelated.
In their Communication on page 1573 ff. J. L. Manson et al. present the coordination polymer [Cu(HF2)2(pyz)]n. They show that spin exchange through Cu-(FHF)2-Cu bridges is about 90 % stronger than through Cu-pyz-Cu bridges.