Recent Developments in Radical Cross-Coupling of Redox-Active Cycloketone Oximes

Recent years have witnessed a renaissance of radical cross-coupling of cycloketone oximes which served as active cyanoalkyl radical via ring fragmentation in various transformations. It provided an efficient and practical strategy to introduce cyanoalkyl groups into organic compounds without using toxic cyanide sources. In this review, a comprehensive overview of recent advances in the field of redox-active cycloketone oximes-based cross-couplings were covered. This review was categorized into two broad parts: non-photocatalyzed and photocatalyzed cross-couplings according to the reaction conditions. Moreover, the two broad parts were further divided into several sub-sections depending on the nature of the bond formation. Some representative examples along with reaction mechanisms were also discussed. 1. Introduction 2. Transition-Metal Catalyzed Cross-Coupling Reactions 2.1. C(sp(3))-C(sp(3)) Bond Formation 2.2. C(sp(3))-C(sp(2)) Bond Formation 2.3. C(sp(3))-C(sp) Bond Formation 2.4. C(sp(3)) N/O/S/Se Bond Formation 3. Microwave-Promoted Cross-Coupling Reactions 4. Gallic acid-Promoted Cross-Coupling Reactions 5. DMAc/B-2(OH)(4) or DMAc-Promoted Cross-Coupling Reactions 6. Photocatalyzed Cross-Couplings Reactions 6.1. Reductive Activation Modes of Cycloketone Oximes 6.2. Oxidative Activation Modes of Cycloketone Oximes 7. Conclusion