Metal-Catalyzed Oxidative Coupling of Ketones and Ketone Enolates

Abstract

Recent years have witnessed a significant advancement in the field of radical oxidative coupling of ketones towards the synthesis of highly useful synthetic building blocks, such as 1,4-dicarbonyl compounds, and biologically important heterocyclic and carbocyclic compounds. Besides oxidative homo- and cross-coupling of enolates, other powerful methods involving direct C(sp3)–H functionalizations of ketones­ have emerged towards the synthesis of 1,4-dicarbonyl compounds. Moreover, direct α-C–H functionalization of ketones has also allowed an efficient access to carbocycles and heterocycles. This review summarizes all these developments made since 2008 in the field of metal-catalyzed/promoted radical-mediated functionalization of ketones at the α-position.1 Introduction2 Synthesis of 1,4-Dicarbonyl Compounds3 Synthesis of Heterocyclic Scaffolds4 Synthesis of Carbocyclic Scaffolds5 Conclusion

Radical Reactions in Alkaloid Synthesis: A Perspective from Carbon Radical Precursors

“…The oxidative inter‐ and intramolecular coupling of two different carbonyl species using soluble copper(II) or iron(III) salts as oxidants has been extensively researched in Baran's laboratory , . In the synthesis of stephacidin A (Scheme a), a stereocontrolled assembly of two of the three stereocenters was accomplished using an intramolecular oxidative coupling.…”

Titanium-Mediated Domino Cross-Coupling/Cyclodehydration and Aldol-Addition/Cyclocondensation: Concise and Regioselective Synthesis of Polysubstituted and Fused Furans

“…To obtain other substituted furans derived from ketones and α-haloketones, multistep reactions are often required (Scheme , Route b) . Ketones can be first transformed into their corresponding stabilized enolate, and then coupled with α-haloketones to afford 1,4-diketones, followed by dehydration to produce various substituted furans . The latter protocol has a wide substrate scope, and is capable of tolerating diverse functional groups; however, the tedious experimental operation, poor total yields, and difficulty in the final Paal–Knorr furan reaction detract from their synthetic utility…”

Studies toward synthesis of the core skeleton of spiroaspertrione A

“…As an efficient synthetic method to directly construct C-C bonds, the oxidative coupling reaction of enol derivatives has been applied in the syntheses of polyketides, alkaloids, and other natural products. ( Murarka and Antonchick 2018 ). Although the first oxidative coupling reaction of enol derivatives dates back to 1935, it did not receive widespread attention from chemists until the 1970s because the efficiency and practicality of this reaction were less than satisfactory ( Fujii et al, 1992 ; Kohno and Narasaka 1995 ; Ryter and Livinghouse 1998 ; Ekebergh et al, 2011 ; Rathke and Lindert 1971 ; Dessau and Heiba 1974 ; Xie and Huang 2010 ; Renaud and Fox 1998 ).…”