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Synthesis 2002(5): 0579-0594
DOI: 10.1055/s-2002-23535
REVIEW
© Georg Thieme Verlag Stuttgart · New York

Asymmetric Wittig Type Reactions

Tobias Rein*a,b,c, Torben M. Pedersenc,d
a AstraZeneca R&D Södertälje, Discovery Chemistry, 15185 Södertälje, Sweden¹
Fax: +46(8)55328892; e-Mail: Tobias.Rein@astrazeneca.com;
b Department of Chemistry, Organic Chemistry, Royal Institute of Technology, 10044 Stockholm, Sweden
c Department of Chemistry, Technical University of Denmark, Building 201, Kemitorvet, 2800 Kgs. Lyngby, Denmark
d Department of Chemistry, Stanford University, Stanford, California 94305, USA¹
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Publikationsverlauf

Received 14 November 2001
Publikationsdatum:
02. April 2002 (online)

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Abstract

The Wittig reaction and related methods for synthesis of C=C double bonds belong to the standard repertoire of the synthetic chemist. Studies of asymmetric versions of these reactions have been increasing in recent years and applications of such processes to complex molecule synthesis have begun to emerge. In this review, we will emphasise the recent advances in developing methods and synthetic applications of these reactions, but earlier results will be covered as well to place the recent results in context.

  • 1 Introduction

  • 2 Reactions with Achiral Monocarbonyl Substrates

  • 2.1 Reactions with Symmetrically Substituted Monoketones

  • 2.2 Synthesis of Chiral Allenes from Ketenes or Acid Halides

  • 3 Reactions with Chiral, Nonracemic Monoketones

  • 4 Kinetic Resolution

  • 4.1 Resolution of Racemic Monocarbonyl Compounds

  • 4.2 Resolution of Racemic Wittig Reagents

  • 5 Dynamic Resolution

  • 6 Other Strategies Based on Resolution of Enantiomers

  • 6.1 Parallel Kinetic Resolution

  • 6.2 Enantioconvergent Synthesis by Sequential Asymmetric HWE Reaction and Palladium-Catalyzed Nucleophilic Allylic Substitution

  • 7 Desymmetrization of Prochiral Dicarbonyl Substrates

  • 8 Future Perspectives, Concluding Remarks

Key words

asymmetric synthesis - asymmetric Wittig reactions - kinetic resolution - enantioconvergent synthesis - desymmetrization

1

Present address.

11

Later results have cast some doubt on the levels of asymmetric induction reported in this paper; see ref. [14a]

28

The structure of the alkyl group in the phosphoryl unit was not specified in the original article.

39

The stoichiometry of the reaction, i.e. the ratio of 63:64, was not reported.

40

The yields given are based on the Wittig type reagent as limiting reactant; 2 equivalents of the substrate were used.

42

The descriptors R and S refer to the stereocenter originating from the substrate.

46

Note that the chiral reagents 14b and 25 all contain the same enantiomer of the chiral auxiliary.

53

The absolute configuration of the product was only tentatively assigned.

58

This can be explained by the fact that the slower reacting enantiomer is continuously racemized and thus not accumulated as in an ordinary kinetic resolution.

63

This is of course primarily an issue in intermolecular reactions, where the functional groups involved in the reaction can be present in different amounts.