Synthesis 2011(21): 3389-3407  
DOI: 10.1055/s-0030-1260233
REVIEW
© Georg Thieme Verlag Stuttgart ˙ New York

Transition-Metal-Catalyzed Rearrangements of Small Cycloalkanes: Regioselectivity Trends in β-Carbon Elimination Reactions

Christophe Aïssa*
Department of Chemistry, University of Liverpool, Crown Street, L69 7ZD, UK
Fax: +44(151)7943588; e-Mail: aissa@liverpool.ac.uk;
Further Information

Publication History

Received 17 June 2011
Publication Date:
20 September 2011 (online)

Abstract

In this review, the regioselectivity of transition-metal-catalyzed ring cleavage of cyclopropanes and cyclobutanes by β-carbon elimination is analyzed using experimental results and rationalization models from the literature. Most models proposed are generally consistent with the following trends: Cleavage of the less substituted bond of the small cycloalkane is favored by a minimization of steric hindrance, whereas cleavage of the more substituted bond becomes possible if steric hindrance is limited and if the substituent is electron-withdrawing or if it can coordinate the metal. Importantly, steric congestion can easily offset electronic activation. Moreover, regioselectivity models appear to be more generally applicable to cyclopropanes than to cyclobutanes.

1 Introduction

2 Important Features of β-C Elimination in Small Cyclo­alkanes

2.1 Reversibility of Ring-Opening β-C Elimination

2.2 Syn-Coplanarity of Ring-Opening β-C Elimination

2.3 Oxidative Addition during Ring-Opening β-C Elimination

2.4 Comparison with Other Transition-Metal-Catalyzed Ring-Opening Reactions

3 Case Studies

3.1 β-C Elimination Involving a Carbon-Metal Bond

3.1.1 Methylenecyclopropanes

3.1.2 Alkylidenecyclopropanes

3.1.3 Vinylcyclopropanes

3.1.4 Alkynylcyclopropanes

3.1.5 Allenylcycloalkanes

3.1.6 Phenyl-Substituted Cyclopropanes

3.1.7 Regioselective Ring Opening of Cyclobutane Derivatives to Cyclooctenones

3.2 β-C Elimination Involving a Nitrogen-Metal Bond

3.3 β-C Elimination Involving an Oxygen-Metal Bond

4 Conclusion