Synthesis 2010(6): 893-907  
DOI: 10.1055/s-0029-1218664
REVIEW
© Georg Thieme Verlag Stuttgart ˙ New York

Advances in 2-(Alkoxycarbonyl)allylboration of Carbonyl Compounds and Other Direct Methods for the Preparation of α-Exo-Alkylidene γ-Lactones

Tim G. Elford, Dennis G. Hall*
Department of Chemistry, University of Alberta, W5-07 Gunning-Lemieux Chemistry Centre, Edmonton, AB, T6G 2G2, Canada
Fax: +1(780)4928231; e-Mail: dennis.hall@ualberta.ca;
Further Information

Publication History

Received 14 October 2009
Publication Date:
05 February 2010 (online)

Abstract

Reagents and methodologies allowing for direct preparation of α-exo-alkylidene γ-lactones are of great interest because of the multiple biological properties demonstrated by these natural and unnatural compounds. Relatively few simple and direct methods are available for the preparation of these important compounds, and these methods along with their applications in target-oriented and diversity-oriented synthesis are covered in this review focusing on the most recent advances in the literature.

1 Introduction

1.1 Importance of α-Exo-Methylene and α-Exo-Alkylidene γ-Lactones

1.2 Overview of Indirect Preparative Methods

2 Direct Preparative Methods by Additions of 2-(Alkoxycarbonyl)allylmetal Reagents to Aldehydes and Ketones

2.1 Thermal Additions of 2-(Alkoxycarbonyl)allyl Boronates

2.2 Lewis Acid Catalyzed Additions of 2-(Alkoxycarbonyl)allyl Boronates

2.3 Brønsted Acid Catalyzed Additions of 2-(Alkoxycarbonyl)allyl Boronates

2.4 Preparation of Libraries of α-Exo-Methylene γ-Lactones and Their Functionalization into α-Exo-Alkylidene γ-Lactones

3 Additions of Other 2-(Alkoxycarbonyl)allylmetal Reagents

4 Barbier-Type Additions with 2-(Alkoxycarbonyl)allyl Halides

5 Other Direct Methods

6 Conclusion