List Science of Synthesis: Asymmetric Organocatalysis Vol. 1

Lewis Base and Acid Catalysts
1. Auflage 2014
ISBN: 978-3-13-178981-5
Verlag: Thieme
Format: PDF
Kopierschutz: Adobe DRM (»Systemvoraussetzungen)

E-Book, Deutsch, Englisch, 992 Seiten, PDF, Format (B × H): 170 mm x 240 mm

Reihe: Science of Synthesis

Asymmetric Organocatalysis comprehensively covers all the catalysts and reactions within the activation modes Lewis base catalysis and Lewis acid catalysis. Typical or general experimental procedures as well as mechanistic, technical and theoretical aspects are included, allowing the reader to clearly see how simple, clean and efficient this chemistry is.

- Authoritative, broad overview of the field, compiled by 36 experts
- Critical presentation of the best organocatalytic and related methodologies available today for practical asymmetric synthesis
- Provides alternative, greener syntheses with simple and easily used catalysts helping avoid the use of expensive and/or toxic metals

Zielgruppe

Wissenschaftler

Autoren/Hrsg.

List, Benjamin

Fachgebiete

• Naturwissenschaften Chemie Organische Chemie

Inhaltsverzeichnis

1.1 Lewis Bases
1.1.1 Enamine Catalysis of Intramolecular Aldol Reactions
1.1.2 Enamine Catalysis of Intermolecular Aldol Reactions
1.1.3 Enamine Catalysis of Mannich Reactions
1.1.4 Enamine Catalysis of Michael Reactions
1.1.5 Enamine Catalysis of a-Functionalizations and Alkylations
1.1.6 SOMO and Radical Chemistry in Organocatalysis
1.1.7 Iminium Catalysis
1.1.8 Iminium Catalysis with Primary Amines
1.1.9 Applications of Aminocatalysis in Target-Oriented Synthesis
1.1.10 Tertiary Amine and Phosphine-Catalyzed Reactions of Ketenes and a-Halo Ketones
1.1.11 Chiral DMAP-Type Catalysts for Acyl-Transfer Reactions
1.1.12 Non-DMAP-Type Catalysts for Acyl-Transfer Reactions
1.1.13 Carbene-Catalyzed Benzoin Reactions
1.1.14 Carbene-Catalyzed Stetter Reactions
1.1.15 N-Heterocyclic Carbene Catalyzed Reactions of a-Functionalized Aldehydes
1.1.16 (Aza)-Morita–Baylis–Hillman Reactions
1.1.17 Phosphine Catalysis
1.2 Lewis Acids
1.2.1 Asymmetric Ketone and Iminium Salt Catalyzed Epoxidations
1.2.2 Lewis Acid Organocatalysts Other than Ketone and Iminium Salt Catalysts

Leseproben

Abstracts
1.1.1 Enamine Catalysis of Intramolecular Aldol Reactions
X.-W. Wang, Y. Wang, and J. Jia In this review, organocatalytic intramolecular aldol reactions are classified into three different types according to their enolization mode: enolendo aldolizations, enolexo aldolizations, and transannular aldolizations. The enantioselective enamine catalysis of these reactions using chiral, enantiomerically pure primary and secondary amines as catalysts is discussed. Following the logic of this volume, the chapter focuses on the more synthetically useful approaches. Keywords: intramolecular • aldol • enamine • catalysis • enolendo • enolexo • transannular 1.1.2 Enamine Catalysis of Intermolecular Aldol Reactions
S. M. Yliniemelä-Sipari, A. Piisola, and P. M. Pihko This review discusses enamine catalysis of intermolecular aldol reactions. The organocatalytic approach to these carbon—carbon bond-forming reactions between enolizable carbonyl compounds and aldehydes or ketones is discussed from a practical standpoint, and is illustrated with examples from the literature. The scope and the current limitations of the protocols are presented. The origins of the limitations, based on chemoselectivity problems related to the activation of starting materials, are also described. Keywords: intermolecular aldol reaction • ganocatalysis asymmetric synthesis • enamine catalysis • organocataltsis 1.1.3 Enamine Catalysis of Mannich Reactions
M. Benohoud and Y. Hayashi Chiral primary and secondary amines catalyze the Mannich reaction of imines and carbonyl compounds to diastereoselectively generate ß-amino carbonyl compounds with excellent enantioselectivity. The design of amine catalysts and the judicious choice of the substituent on the nitrogen of the imine allows the selective formation of the syn- or anti-Mannich products. The imine component can be preformed or generated in situ from an amine and an aldehyde or by desulfonylation of a-amido sulfones. Imines can bear aromatic, carbamate, or sulfonate N-substituents. Since the initial development of amine-catalyzed Mannich reactions, the scope of carbonyl compounds has been extended from simple acetone to cyclic ketones, ketones substituted with heteroatoms, and aldehydes such as acetaldehyde, which is known to be difficult to handle because of its high reactivity. Mannich adducts formed in these asymmetric organocatalyzed processes are generally obtained with good yields and high diastereo- and enantioselectivities. There are several noteworthy features of this reaction: (1) the reactions are operationally simple; (2) water and air do not need to be strictly excluded; (3) amine catalysts are available, or can be prepared, in both enantiomeric forms; (4) in several procedures the catalyst loading can be reduced to <5 mol%; and (5) high enantioselectivities can be obtained. The asymmetric amine-catalyzed Mannich reaction is a practical and useful method for the synthesis of nitrogen-containing chiral molecules. Keywords: asymmetric Mannich reaction • chiral amines • enamines • imines • ß-amino carbonyls 1.1.4 Enamine Catalysis of Michael Reactions
N. Mase This chapter addresses significant achievements in asymmetric synthesis focusing on enamine-based organocatalytic direct Michael reactions. The description of methods for Michael reactions is subdivided on the basis of various classes of intramolecular, intermolecular, and domino reactions. In addition, these are further subdivided on the basis of donors (nucleophiles) and acceptors (electrophiles): ketones and aldehydes as the donors and a,ß-unsaturated carbonyl compounds, nitroalkenes, vinyl sulfones, and vinylphosphonates as the acceptors. ? Keywords: conjugate addition reactions • domino reactions • enamine catalysis • enamines • iminium catalysis • intermolecular reactions • intramolecular reactions • Michael acceptors • Michael addition • Michael donors • one-pot process • organocatalysis • reductive Michael reactions 1.1.5 Enamine Catalysis of a-Functionalizations and Alkylations
S. Mukherjee Since the turn of this century, asymmetric enamine catalysis has given rise to a plethora of synthetically useful transformations. This section describes some of the most efficient and practical methods for enamine catalyzed asymmetric a-functionalizations and alkylations. The first part of this review deals with the introduction of different heteroatom functionalities (e.g., nitrogen, oxygen, halogens, sulfur, or selenium) at the a-position of aldehydes and ketones, whereas methods for the formation of C—C bonds (e.g., alkylation, allylation, or arylation) are described in the latter part. Keywords: alkylation • allylation • arylation • asymmetric catalysis • enamine • a-functionalization • organocatalysis 1.1.6 SOMO and Radical Chemistry in Organocatalysis
D. W. C. MacMillan and T. D. Beeson This chapter describes the design and development of singly occupied molecular orbital (SOMO) catalysis. This new mode of organocatalytic activation is founded upon the mechanistic hypothesis that the one-electron oxidation of a transient enamine intermediate, derived from a carbonyl compound and a chiral amine catalyst, will render a 3p-electron SOMO radical cation that is subject to enantiofacial discrimination. This chiral SOMO-activated species can readily combine with SOMO nucleophiles in unique asymmetric bond constructions to enable previously unknown transformations. Many SOMO nucleophiles have been shown to participate with radical cations and, correspondingly, a diverse range of chemistry, such as carbon—carbon and carbon—heteroatom bond formations, formal [4 + 2] cycloadditions, and polyene cyclizations, has been implemented. Keywords: SOMO • nucleophile • radical cation • iminium • enamine • aldehydes • ketones • carbon—carbon bond formation • carbon—heteroatom bond formation • cycloaddition • cyclization 1.1.7 Iminium Catalysis
D. W. C. MacMillan and A. J. B. Watson Chiral amine catalysts condense with a,ß-unsaturated carbonyl compounds to generate transient chiral iminium ions. These activated intermediates are then able to participate in enantioselective carbon—carbon and carbon—heteroatom bond formation with a broad range of nucleophilic partners. ? Keywords: aldehydes • amines • asymmetric catalysis • asymmetric synthesis • chiral compounds • chirality • conjugate addition • diastereoselectivity • enals • enamines • enones • iminium salts • Michael addition • nucleophilic addition 1.1.8 Iminium Catalysis with Primary Amines
Y. Liu and P. Melchiorre Advances in catalytic, enantioselective additions of a variety of nucleophiles to enals and enones under the iminium activation of chiral primary amines are described. Primary amine catalysis offers the unique possibility of chemical reactions between sterically demanding partners, thus overcoming the inherent difficulties of chiral secondary amines in generating congested covalent intermediates. This has allowed for the expansion of iminium catalysis to include difficult carbonyl substrates such as a,ß-unsaturated ketones and a-branched a,ß-unsaturated aldehydes. The selected methods represent the state of the art in the rapidly evolving area of iminium catalysis with primary amines, which provides a suitable synthetic tool to enantioselectively functionalize hindered unsaturated carbonyl compounds at their a- and ß-positions. Keywords: aldehydes • amines • asymmetric catalysis • asymmetric synthesis • conjugate addition • cycloaddition • ketones • iminium catalysis • organocatalysis 1.1.9 Applications of Aminocatalysis in Target-Oriented Synthesis
M. Christmann This chapter covers applications of aminocatalysis to the synthesis of natural products and active pharmaceutical ingredients. The activation modes discussed include enamine activation, iminium activation, and dienamine activation. Following the organocatalytic key step, a detailed description of the completion of the individual syntheses is provided. Finally, an outlook on future prospects concludes this section. Keywords: natural products • total synthesis • Mannich reaction • Aldol reaction • Michael reaction • prolines • enamines • Diels–Alder reaction • iminium salts • carbonyl compounds • catalysts • drugs 1.1.10 Tertiary Amine and Phosphine-Catalyzed Reactions of Ketenes and a-Halo Ketones
S. Chen, E. C. Salo, and N. J. Kerrigan Although the...