The conjugate addition of carbon nucleophiles to acceptor activated olefins is one of the most important reactions for carbon-carbon bond formation. With optically active metal complexes this transformation can be catalyzed enantioselectively. This review is a collection of the newer literature (since 2001) on this topic. The metal salts and complexes applied are in a broad range, starting from solely Lewis acidic M(II) and M(III) compounds, such as magnesium, zinc, boron, aluminum and the lanthanoids. Transitionmetal catalysts suitable for asymmetric conjugate additions are compounds of ruthenium, iridium, nickel, and palladium. The most flourishing fields are, however, the catalysis with rhodium and copper complexes. Rhodium catalysts often have a chiral diphosphane like BINAP, or an optically active olefin as the ligand, the latter being a newer development. The privileged ligand structures for copper catalysts are monodentate phosphoramidites with axially chiral BINOL or other biphenol units.

In memoriam Michael BrommerKeywords: Alkynes / α-Bromostyrenes / Conjugate addition / Corey-Fuchs procedure / Heterocycles / Pyrans / ThiopyransTetrahydropyran-4-one and tetrahydrothiopyran-4-one derivatives with a 3-aryl substituent were synthesized by double-conjugate addition of water or H 2 S to divinyl ketones. These starting materials were prepared in two steps by conversion of lithiated α-bromostyrene derivatives with acrolein or cinnamaldehyde and subsequent oxidation of the divinyl alcohols with MnO 2 . The electron-rich α-bromostyrene building blocks were prepared by addition of HBr to the respec-

The Shapiro reaction of acetophenone is the key in a convenient three‐step access to a divinyl ketone which is further transformed by double aza‐Michael reactions with primary amines into N‐substituted 3‐phenyl‐4‐piperidones. In the case of N‐benzyl and N‐allyl derivatives, the piperidine nitrogen atom can be deprotected and further functionalized, for example, by carboxamide, carbamate, or urea formation.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

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SummaryThe present work describes the robust synthesis of Ru alkylidene complexes (PCy3)2Cl2Ru=CHR – precursors for metathesis catalysts. Moreover, the dynamic behavior of complexes where R = 2-naphthyl and 2-thienyl was studied. 1H NMR techniques were employed to establish the preferred conformations in solution for both complexes and the energy barrier for rotation around single (Ru=)CH–C(thienyl) bond was estimated (ΔG ≠ 303K = 12.6 kcal/mol).