Synthesis of α-exo-Methylene-γ-butyrolactones: Recent Developments and Applications in Natural Product Synthesis
Weilong Liu, Nicolas Winssinger
Abstract
Abstract The α-exo-methylene-γ-butyrolactone moiety is present in a vast array of structurally diverse natural products and is often central to their biological activity. In this short review, we summarize new approaches to α-exo-methylene-γ-butyrolactones developed over the past decade as well as their applications in total synthesis. 1 Introduction 2 Approaches to α-exo-Methylene-γ-butyrolactones 2.1 Enantioselective Synthesis via Lactonization Approaches 2.2 Enantioselective Halolactonizations 2.3 Enantioselective Barbier-Type Allylation 2.4 C–H Insertion/Olefination Sequences 2.5 Alkene Cyclization 2.6 Strain-Driven Dyotropic Rearrangement 3 β-(Hydroxymethylalkyl)-α-exo-methylene-γ-butyrolactones 4 Applications in Total Synthesis 4.1 Sesquiterpene Lactones 4.2 Lignans 4.3 Other Monocyclic Natural Products 4.4 Choice of Methodology in Recent Total Syntheses 5 Summary and Outlook