Organocatalysis Episode 1 doc

[...]... Universitätsstr 31, 93053 Regensburg, Germany Ernst Schering Foundation Symposium Proceedings, Vol 2, pp 1 43 DOI 10 .10 07/2789_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. .. Scheme 10 Proline: a bifunctional catalyst New Concepts for Organocatalysis 15 Scheme 11 Phosphoric acid catalysis pioneered by Akiyama and Terada et al 2004; also see Uraguchi et al 2005; Terada et al 2005) demonstrated, in pioneering studies, that relatively strong chiral binaphtholderived phosphoric acids are efficient and highly enantioselective catalysts for addition reactions to aldimines (Scheme 11 )... studies have contributed significantly to the elucidation of the reaction mechanism We found that in contrast with earlier proposals (Agami et al 19 84, 19 86, 19 88; Puchot et al 19 86; Agami and Puchot 19 86), 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... to Iminium Catalysis 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... enantioselective catalysts for addition reactions to aldimines (Scheme 11 ) 3 .1 Catalytic Asymmetric Pictet–Spengler Reaction The Pictet–Spengler reaction (Pictet and Spengler 19 11; Tatsui 19 28) is an important acid-catalyzed transformation frequently used in the laboratory as well as by various organisms for the synthesis of tetrahydro-β- 16 S.C Pan, B List carbolines and tetrahydroisoquinolines from carbonyl... facile and efficient removal of the N-protecting group to yield the unfunctionalized amine is required Generally, the removal of the most commonly New Concepts for Organocatalysis Scheme 7 Enamine catalysis of nucleophilic substitution reactions 11 12 S.C Pan, B List Scheme 8 Proline-catalyzed asymmetric Mannich reactions used p-methoxyphenyl (PMP) group from nitrogen requires rather drastic oxidative conditions... After complete consumption of the starting material (10 h), a large amount of the de- New Concepts for Organocatalysis 13 Fig 2 The reaction of isovaleraldehyde with 2-naphthyl N-Boc-imine in the presence of (S)-proline (20 mol%) in CH3 CN a Homogenous reaction mixture after mixing all components b Reaction mixture after completion of the reaction (10 h) sired product had precipitated and could easily... Corrensstraße 40, 4 814 9 Münster, Germany (e-mail: khirano@uni-muenster.de) Hüttl, M.R.M Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany List, B Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany (e-mail: list@mpi-muelheim.mpg.de) Niemeier, O Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen,... Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany (e-mail: reetz@mpi-muelheim.mpg.de) List, B 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, 13 342 Berlin, Germany (e-mail: stefan.jaroch@bayerhealthcare.com) Weinmann, H Bayer Schering Pharma AG, 13 442 Berlin, Germany... with various electrophiles or undergoes pericyclic reactions The first example of asymmetric enamine catalysis is the Hajos–Parrish–Eder– 4 S.C Pan, B List Sauer–Wiechert reaction (Eder et al 19 71; Hajos and Parrish 19 74; for a review, see List 2002b; Scheme 2), an intramolecular aldol reaction catalyzed by proline Despite its use in natural product and steroid synthesis, the scope of the Hajos–Parrish–Eder–Sauer–Wiechert . Reactions 10 2.4 TheProline-CatalyzedAsymmetricMannichReactions 10 3 BrønstedAcidCatalysis 14 3 .1 CatalyticAsymmetricPictet–SpenglerReaction 15 3.2 OrganocatalyticAsymmetricReductiveAmination 17 4. Products M. Christmann 12 5 Asymmetric Organocatalysis on a Technical Scale: Current Status and Future Challenges H. Gröger 14 1 Nucleophilic Carbenes as Organocatalysts F. Glorius, K. Hirano 15 9 N-Heterocyclic. mechanism. We found that in contrast with earlier proposals (Agami et al. 19 84, 19 86, 19 88; Puchot et al. 19 86; Agami and Puchot 19 86), proline-catalyzed aldol reactions