Synthetic Approaches to Coronafacic Acid, Coronamic Acid, and Coronatine

Abstract

The phytotoxin coronatine (COR) is a functional mimic of the active plant hormone (+)-7-iso-jasmonoyl- l -isoleucine (JA-IIe), which regulates stress responses. Structurally, COR is composed of a core unit, coronafacic acid (CFA), which is connected to coronamic acid (CMA), via an amide linkage. COR has been found to induce a range of biological activity in plants and based on its biological profile, COR, as well as CFA, and CMA are attractive starting points for agrochemical discovery, resulting in numerous total synthesis efforts. This review will discuss the synthetic approaches towards CFA, CMA and, ultimately COR, to date. 1 Introduction 2 Total Synthesis of Coronafacic Acid (CFA, 4) 2.1 Mapping Synthetic Strategies 2.2 Intermolecular Diels–Alder Approaches 2.3 Intramolecular Diels–Alder Approaches 2.4 Conjugate Addition Approaches 2.5 Haller–Bauer Approaches 2.6 Intramolecular Cyclisation Approaches 2.7 Oxy-Cope Approaches 3 Total Synthesis of Coronamic Acid (CMA, 5) 3.1 Mapping Synthetic Strategies 3.2 Final Installation of C1 3.3 Final Installation of C2 3.4 Final Installation of C3 4 Total Synthesis of Coronatine (COR, 1) 5 Conclusions