Cover Picture: Umpolung by N-Heterocyclic Carbenes: Generation and Reactivity of the Elusive 2,2-Diamino Enols (Breslow Intermediates) (Angew. Chem. Int. Ed. 49/2012)



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Breslow intermediates of N-heterocyclic carbene (NHC) catalyzed Umpolung reactions have been generated by combining saturated NHCs with aldehydes. In their Communication on page 12370 ff., A. Berkessel et al. report the observation of these pivotal but hitherto elusive intermediates. Indeed, much water has flown down the Rhine since the first postulation of amino enols as the “umpoled” form of aldehydes in 1958 until their characterization reported herein! (Graphics & photo: Adrian von der Höh.)

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Pentadecker Supramolecules

In their Communication on page 12194 ff., M. A. Petrukhina et al. describe pentadecker sandwich complexes with a Li–alkoxo core between corannulene bowls. These supramolecular aggregates may be useful for Li-ion-battery design.

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Drug Discovery

A small-molecule inhibitor found to suppress the TLR1/TLR2-mediated inflammation response is presented by H. Yin et al. in their Communication on page 12246 ff. This compound is a valuable probe for these important signaling receptors.

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Host–Guest Systems

In their Communication on page 12233 ff., P. Jonkheijm et al. describe a stable cucurbit[8]uril-mediated system for the preparation of noncovalent cell adhesive surfaces that can be electrochemically controlled.

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