Synthesis 2006(9): 1391-1401  
DOI: 10.1055/s-2006-926405
REVIEW
© Georg Thieme Verlag Stuttgart · New York

Lewis Base Catalyzed Asymmetric Reactions Involving Hypervalent Silicate Intermediates

Yuya Orito, Makoto Nakajima
Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Kumamoto 862-0973, Japan
Fax: +81(96)3627692; e-Mail: nakajima@gpo.kumamoto-u.ac.jp;
Further Information

Publication History

Received 30 September 2005
Publication Date:
27 March 2006 (online)

Abstract

The development of catalytic enantioselective reactions is a challenging area in synthetic organic chemistry. In the last decade, numerous chiral metal complexes, which act as Lewis acids, have been very successful. However, Lewis base catalyzed asymmetric reactions are also attracting attention. Recent developments in silicon-based chemistry have led to new asymmetric reactions, which involve so-called hypervalent silicates as intermediates, wherein new types of organocatalysts are often utilized as promoters. This review presents the progress in silicate-mediated asymmetric reactions catalyzed by chiral Lewis bases, particularly those based on various types of silicon compounds.

1 Introduction: Reactivity of Hypervalent Silicates

2 Reactions of Trialkoxysilyl Compounds

2.1 Asymmetric Reduction with Trialkoxysilanes

2.2 Asymmetric Aldol Reaction of Trimethoxysilyl Enol Ethers

3 Reactions of Trichlorosilyl Compounds

3.1 Asymmetric Allylation of Allyltrichlorosilanes

3.1.1 Phosphoramides as Lewis Base Catalysts

3.1.2 N-Oxides as Lewis Base Catalysts

3.1.3 Formamides as Lewis Base Catalysts

3.1.4 Other Organocatalysts

3.2 Asymmetric Aldol Reaction of Trichlorosilyl Enol Ethers

3.3 Asymmetric Reduction with Trichlorosilanes

3.4 Asymmetric Ring-Opening Reaction of Epoxides

3.5 Hypervalent Silicates as Lewis Acid Catalysts

4 Reactions of Trimethylsilyl Compounds

5 Conclusion

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Kotani, S.; Hashimoto, S.; Nakajima, M. Synlett, in press.