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Superbases for Organic Synthesis: Guanidines, Amidines, Phosphazenes and Related Organocatalysts

Superbases for Organic Synthesis: Guanidines, Amidines, Phosphazenes and Related Organocatalysts

Tsutomu Ishikawa

ISBN: 978-0-470-74086-6 January 2009 336 Pages




Guanidines, amidines and phosphazenes have been attracting attention in organic synthesis due to their potential functionality resulting from their extremely strong basicity. They are also promising catalysts because of their potential for easy molecular modification, possible recyclability, and reduced or zero toxicity. Importantly, these molecules can be derived as natural products – valuable as scientists move towards “sustainable chemistry”, where reagents and catalysts are derived from biomaterial sources.

Superbases for Organic Synthesis is an essential guide to these important molecules for preparative organic synthesis. Topics covered include the following aspects:

  • an introduction to organosuperbases
  • physicochemical properties of organic superbases
  • amidines and guanidines in organic synthesis
  • phosphazene: preparation, reaction and catalytic role
  • polymer-supported organosuperbases
  • application of organosuperbases to total synthesis
  • related organocatalysts: proton sponges and urea derivatives
  • amidines and guanidines in natural products and medicines

Superbases for Organic Synthesis is a comprehensive, authoritative and up-to-date guide to these important reagents for organic chemists, drug discovery researchers and those interested in the chemistry of natural products.



List of Contributors.

1. General Aspects of Organosuperbases (Tsutomu Ishikawa).

2. Physicochemical Properties of Organic Superbases (Davor Margetic).

2.1 Introduction.

2.2 Proton sponges.

2.3 Amidines.

2.4 Guanidines.

2.5 Phosphazenes.

2.6 Guanidinophosphazenes.

2.7 Other Phosphorus Containing Superbases: Verkade’s Proazaphosphatranes.

2.8 Theoretical Methods.

2.9 Concluding Remarks.


3. Amidines in Organic Synthesis (Tsutomu Ishikawa and Takuya Kumamoto).

3.1 Introduction.

3.2 Preparation of Amidine.

3.3 Application of Amidines to Organic Synthesis.

3.4 Amidinium Salt: Design and Synthesis.

3.5 Concluding Remarks.


4. Guanidines in Organic Synthesis (Tsutomu Ishikawa).

4.1. Introduction.

4.2. Preparation of Chiral Guanidines.

4.3 Guanidines as Synthetic Tools.

4.4 Guanidinium Salt.

4.5 Concluding Remarks.


5. Phosphazene: Preparation, Reaction and Catalytic Role (Yoshinori Kondo).

5.1 Introduction.

5.2 Deprotonative Transformations Using Stoichiometric Phosphazenes.

5.3 Transformation Using Phosphazene Catalyst.

5.4 Proazaphosphatrane Base (Verkade’s Base).

5.5 Concluding Remarks.


6. Polymer-supported Organosuperbases (Hiyoshizo Kotsuki).

6.1 Introduction.

6.2 Acylation reactions.

6.3 Alkylation Reactions.

6.4 Heterocyclization.

6.5 Miscellaneous.

6.6 Concluding Remarks.


7. Application of Organosuperbases to Total Synthesis (Kazuo Nagasawa).

7.1 Introduction.

7.2 Carbon-carbon bond-forming reactions.

7.3 Deprotection.

7.4 Elimination.

7.5 Ether synthesis.

7.6 Heteroatom conjugate addition.

7.7 Isomerization.

7.8 Concluding Remarks.


8. Related Organocatalysts (1): Proton Sponge (Kazuo Nagasawa).

8.1 Introduction.

8.2 Alkylation and Hetero Michael reaction.

8.3 Amide formation.

8.4 Carbon-carbon bond-forming reaction.

8.5 Palladium-catalyzed reaction.

8.6 Concluding Remarks.


9. Related Organocatalysts (2): Urea Derivatives (Waka Nakanishi).

9.1 Introduction.

9.2 Bisphenol as Organoacid Catalyst.

9.3 Urea and Thiourea as Achiral Catalysts.

9.4 Urea and Thiourea as Chiral Catalyst.

9.5 Concluding Remarks.


10. Amidines and Guanidines in Natural Products and Medicines (Takuya Kumamoto).

10.1 Introduction.

10.2 Natural Amidine Derivatives.

10.3 Natural Guanidine Derivatives.

10.4 Medicinal Amidine and Guanidine Derivatives.


11. Perspective (Tsutomu Ishikawa and Davor Margetic).