Synlett 2010(15): 2207-2239  
DOI: 10.1055/s-0030-1258549
ACCOUNT
© Georg Thieme Verlag Stuttgart ˙ New York

Cycloadditions of Allylsilanes - Part 22. [¹] Stereoselective Synthesis of Cyclopentanes and Cyclobutanes by Lewis Acid Promoted [3+2] and [2+2] Cycloadditions of Allylsilanes

Arndt W. Schmidt, Hans-Joachim Knölker*
Department Chemie, Technische Universität Dresden, Bergstr. 66, 01069 Dresden, Germany
Fax: +49(351)46337030; e-Mail: hans-joachim.knoelker@tu-dresden.de;
Further Information

Publication History

Received 21 June 2010
Publication Date:
30 August 2010 (online)

Abstract

The development of Lewis acid promoted [3+2] and [2+2] cycloadditions as a novel methodology for the stereoselective construction of cyclopentanes and cyclobutanes is described. Elegant applications of this methodology to the total synthesis of biologically active terpenoid natural products are presented.

1 Introduction

2 [3+2] Cycloadditions of Allylsilanes

2.1 Synthesis of Silylbicyclo[n.3.0]alkanes

2.2 Synthesis of Silylcyclopentanes

2.3 Domino [3+2] Cycloadditions with Alkynones

2.4 [3+2] Cycloadditions with Cycloalkenones

2.5 Synthesis of Silylspirocyclopentanes

2.6 Asymmetric [3+2] Cycloadditions with Chiral Allylsilanes

3 Transformations of the Silylcyclopentanes

3.1 Conversion of the Silylbicyclo[n.3.0]alkanes into Symmetrical Olefins

3.2 Development of a Modified Fleming-Tamao Oxidation

4 Domino Double [3+2] Cycloaddition/Wagner-Meerwein Rearrangement/Friedel-Crafts Alkylation/Elimination

5 [2+2] Cycloadditions of Allylsilanes

5.1 Mechanism

5.2 Synthesis of (Silylmethyl)cyclobutanes

5.3 Rearrangement of (Silylmethyl)cyclobutanes to Silylcyclopentanes

5.4 Domino [2+2] Cycloadditions with Alkynoic Esters

5.5 Stereospecific [2+2] Cycloadditions

5.6 Modified Fleming-Tamao Oxidation of the (Silylmethyl)cyclobutanes

6 Applications to Natural Product Synthesis

6.1 Angular Triquinanes

6.1.1 (±)-Cameroonanol

6.1.2 (±)-Isocomene and (±)-β-Isocomene

6.2 Cyclobutane Natural Products

6.2.1 (±)-Fragranol

6.2.2 The Oleander Scale Pheromone

7 Conclusion