Highly Strained para-Phenylene-Bridged Macrocycles from Unstrained 1,4-Diketo Macrocycles

Abstract

The conversion of macrocyclic 1,4-diketones to highly strained para-phenylene rings has recently been reported by our laboratory. This synthetic strategy represents a non-cross-coupling-based approach to arene-bridged macrocycles, and an alternative to palladium- and nickel-mediated processes. In this Synpacts article we discuss the development of endgame aromatization protocols for the synthesis of increasingly strained arene systems, as well as potential advantages of the macrocyclic 1,4-diketone approach to selectively functionalized benzenoid macrocycles for future complexity building reactions.1 Introduction2 A Non-Cross-Coupling-Based Approach to Arene-Bridged Macro cycles3 Macrocyclic 1,4-Diketones: Streamlined Synthesis and Size-­Dependent Diastereoselective Grignard Reactions4 Dehydrative Aromatization Reactions: A Powerful Tool for Synthesizing Highly Strained para-Phenylene Units5 Conclusion