[...]... Regensburg, Germany Ernst Schering Foundation Symposium Proceedings, Vol 2, pp 1–43 DOI 10.1007/2789_2008_084 © Springer-Verlag Berlin Heidelberg Published Online: 30 April 2008 New Concepts for Organocatalysis S.C Pan, B List(u) Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany email: list@mpi-muelheim.mpg.de 1 2 2.1 Introduction: Organocatalysis ... Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany (e-mail: list@mpi-muelheim.mpg.de) Jaroch, S Bayer Schering Pharma AG, 13342 Berlin, Germany (e-mail: stefan.jaroch@bayerhealthcare.com) Weinmann, H Bayer Schering Pharma AG, 13442 Berlin, Germany (e-mail: hilmar.weinmann@bayerhealthcare.com) XII List of Editors and Contributors Contributors Bach,T Lehrstuhl... Contributions to S.C Pan, B List 2 organocatalysis from our laboratories include several new and broadly useful concepts such as enamine catalysis and asymmetric counteranion-directed catalysis Our laboratory has discovered the proline-catalyzed direct asymmetric intermolecular aldol reaction and introduced several other organocatalytic reactions 1 Introduction: Organocatalysis When chemists make chiral... catalysis Chemists also use enzymes or even whole cells to synthesize chiral compounds and for a long Fig 1 The three pillars of asymmetric catalysis: biocatalyis, metal catalysis and organocatalysis New Concepts for Organocatalysis 3 time, the perfect enantioselectivities often observed in enzymatic reactions were considered beyond reach for non-biological catalysts Such biological catalysis is increasingly... 6 Conclusions References 2 3 5 8 10 10 14 15 17 22 24 26 28 33 34 Abstract Organocatalysis, catalysis with low-molecular weight catalysts in which a metal is not part of the catalytic principle or the reaction substrate, can be as efficient and selective as metal- or biocatalysis... synthetic metal complexes as catalysts Transition metal catalysts are particularly useful for asymmetric hydrogenations, but may leave possibly toxic traces of heavy metals in the product In contrast, in organocatalysis, a purely organic and metal-free small molecule is used to catalyze a chemical reaction In addition to enriching chemistry with another useful strategy for catalysis, this approach has... Enders et al 2005; Ibrahem et al 2004) and Michael additions (List et al 2001; Enders and Seki 2002) have been developed (List 2004; Allemann et al 2004) Scheme 1 Organocatalytic cycles New Concepts for Organocatalysis 5 Scheme 2 The Hajos–Parrish–Eder–Sauer–Wiechert reaction This concept has also been extended to highly enantioselective αfunctionalizations of aldehydes and ketones such as aminations... of the reaction mechanism We found that in contrast with earlier proposals (Agami et al 1984, 1986, 1988; Puchot et al 1986; Agami and Puchot 1986), proline-catalyzed aldol reactions New Concepts for Organocatalysis 7 Scheme 4 The proposed mechanism and transition state of proline-catalyzed aldolizations do not show any nonlinear effects in the asymmetric catalysis (Hoang et al 2003; Klussmann et al... variety of electrophiles In addition to carbonyl compounds (C = O), these include imines (C = N) in Mannich reactions (List 2000; List et al 2002; Hayashi et al 2003a; Córdova et al 2002c; New Concepts for Organocatalysis 9 Scheme 6 Enamine catalysis of nucleophilic addition reactions Hayashi et al 2003b; Córdova 2003; Notz et al 2003; Enders et al 2005; Ibrahem et al 2004), azodicarboxylates (N = N) (List... aldehydes, and ketones Many of these are normally not accessible using established reactions based on transition metal catalysts or on preformed enolates or enamines, illustrating the complimentary nature of organocatalysis and metallocatalysis 10 2.3 S.C Pan, B List Enamine Catalysis of Nucleophilic Substitution Reactions The first example of an asymmetric enamine catalytic nucleophilic substitution was a . class="bi x0 y0 w1 h0" alt="" Ernst Schering Foundation Symposium Proceedings 2007-2 Organocatalysis Ernst Schering Foundation Symposium Proceedings 2007-2 Organocatalysis M.T. Reetz, B. List,. the Ernst Schering Foundation enabled us to VI Preface organize a symposium on Organocatalysis, ’ which took place in Berlin, Germany, from 18 to 20 April 2007. The proceedings of this symposium are. Germany Ernst Schering Foundation Symposium P roceedings, Vol. 2, pp. 1–43 DOI 10.1007/2789_2008_084 © Springer-Verlag Berlin Heidelberg Published O nline: 30 April 2008 New Concepts for Organocatalysis S