Synthesis 2005(11): 1727-1747  
DOI: 10.1055/s-2005-869949
REVIEW
© Georg Thieme Verlag Stuttgart · New York

Hypervalent Silicon as a Reactive Site in Selective Bond-Forming Processes

Sebastian Rendler, Martin Oestreich*
Institut für Organische Chemie und Biochemie, Albert-Ludwigs-Universität, Albertstrasse 21, 79104 Freiburg im Breisgau, Germany
Fax: +49(761)2036100; e-Mail: martin.oestreich@orgmail.chemie.uni-freiburg.de;
Further Information

Publication History

Received 24 January 2005
Publication Date:
13 June 2005 (online)

Abstract

Silicon is a truly exceptional element as it serves as a reactive site for an almost infinite number of transformations pertinent to synthetic organic chemistry. Importantly, the intertwined relationship of the valency at silicon and its chemical reactivity re­presents the key to a profound understanding and the design of novel reactions. Thus, these so-called hypervalent silanes are crucial intermediates in silicon-based carbon-carbon bond-forming reactions, whereby tetravalent silanes are conventionally employed in carbon-silicon bond-forming processes. This review aims at a detailed discussion of these mechanistic aspects illustrated with some synthetically significant developments in modern organosilicon chemistry. Recent advances in silicon-mediated, organocatalytic C(sp3)-C(sp3) bond formation directed towards the preparation of aldol and aldol-like products are covered. Silicon-based transition-metal-catalyzed C(spn)-C(sp2) bond formations involving hypervalent silicon intermediates are also included. These seemingly dissimilar reactions will be comparatively juxtaposed.

  • 1 Introduction: Hypervalent Silicon

  • 2 C(sp3)-C(sp3) Bond Formation

  • 2.1 Silicon-Based Chiral Lewis Acids

  • 2.2 Synthesis of Aldol and Aldol-Like Products

  • 2.2.1 Addition of Allylic Silanes to Carbonyl Compounds

  • 2.2.2 Addition of Silicon Enolates to Carbonyl Compounds

  • 3 C(spn)-C(sp2) Bond Formation: Transition-Metal-Catalyzed­ Cross-Coupling Reactions

  • 4 Outlook and Perspective