Oxidation of Alkynes via Catalytic Metal-Vinylidenes

Abstract

Metal-vinylidenes, generated by treatment of terminal alkynes with transition metals, are very useful intermediates in modern synthetic chemistry as shown by the high number of transformations in which they are involved. When a metal-vinylidene is generated in the presence of an oxidant, its immediate oxidation to a ketene occurs. In this short review, recent synthetic applications of the oxidation of alkynes via ketene intermediates from initially formed metal-vinylidenes­ are highlighted.1 Introduction2 Oxidation of Metal-Vinylidenes with Internal Oxidants3 Oxidation of Metal-Vinylidenes with External Oxidants4 Conclusions

Rhodium and Isothiourea Dual Catalysis: Enantiodivergent Transformation of Terminal Alkynes

“…Alkynes are versatile substrates in organic synthesis, and the development of efficient catalytic methodologies that enable their sustainable conversion into functional molecules continues to be an important goal of chemical research . Transition-metal-catalyzed transfer oxygenation of alkynes with either internal or external oxidants through the metal-vinylidene-to-ketene transformation proved to be useful means for the synthesis of carbonyl compounds and their derivatives (Scheme b). Although terminal alkynes are proven to be promising reactants in intermolecular nucleophile additions − and annulation reactions, − their applications in enantioenriched transformations remain largely underused.…”