Recent Advances in Catalytic Stereocontrolled Cycloaddition with Terminal Propargylic Compounds

Terminal propargylic compounds containing an alkyne unit and an alcohol or ester group in the propargylic position have a fairly acidic acetylenic hydrogen atom; this makes them versatile substrates for further chemical transformation. Some transition metals such as ruthenium or copper exhibit specific affinity for terminal propargylic compounds, generating dielectrophilic ruthenium- or copper-allenylidene complexes that show high potential for stereoselective cycloaddition with various bis-nucleophiles. In this review, we highlight this emerging field of catalytic stereoselective cycloaddition with terminal propargylic compounds. Examples of ruthenium-, copper-, palladium-, and gold-catalyzed cycloaddition are given in the article, along with mechanistic considerations. 1 Introduction 2 Ruthenium-Allenylidene Complexes in Enantioselective Cycloaddition 3 Copper-Allenylidene Complexes in Enantioselective Cycloaddition 4 Palladium-Propargyl Complexes in Stereoselective Cycloaddition 5 Gold-Carbenoid Complexes in Stereoselective Cycloaddition 6 Summary and Outlook