The aldol reaction is one of the most important methods for the stereoselective construction of polyketide natural products, not only for nature but also for synthetic chemistry. The tremendous development in the field of aldol additions during the last 30 years has led to more and more total syntheses of complicated natural products. This Review illustrates by means of selected syntheses of natural products the new variants of the aldol addition. This includes aldol additions with various metal enolates, as well as metal-complex-catalyzed, organocatalytic, and biocatalytic methods.

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Nonporous spherical silica nanoparticles resulting from a controlled Stöber process are covalently surface modified with redox-active molecules. Ferrocene, a ruthenium(II) complex with an N2P2Cl2 ligand set, and a sterically hindered biphenylamine are used as modifiers. The resulting materials are characterized by physical, spectroscopic, electrochemical, and chemical methods. The cyclic voltammetric behavior is studied in detail and reveals effects of charge transport by electron hopping along the surface of particles adsorbed on a Pt electrode. The ruthenium(II) complex remains catalytically active with respect to hydrogenation upon immobilization on the particles. Thus, the respective material provides a heterogenized homogeneous hydrogenation catalyst on a solid support.

Die Aldolreaktion gehört zu den wichtigsten Methoden der organischen Synthesechemie für den stereoselektiven Aufbau von polyketiden Naturstoffen. Dabei bedient sich die Natur gleichermaßen wie der präparativ arbeitende Chemiker dieser fundamentalen Reaktion. Die rasante Entwicklung auf dem Gebiet der stereoselektiven Aldolreaktionen während der letzten 30 Jahre führte zur Totalsynthese vieler komplexer Naturstoffe. Dieser Beitrag illustriert anhand ausgewählter Totalsynthesen von Naturstoffen diese neuartigen Varianten der Aldoladdition. Dabei werden Aldoladditionen, die sich unterschiedlicher Metallenolate bedienen, ebenso behandelt wie metallkomplexkatalysierte, organokatalytische sowie biokatalytische Methoden.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.