Selective Open-Shell Nickel Catalysis Driven by Redox-Transmetalation

Abstract Reductive cross-electrophile coupling of organic halides facilitated by open-shell Ni catalysis has emerged as a powerful strategy for the efficient construction of molecular complexity. Despite significant advances, the diversity of catalytic systems has remained relatively limited, as the reductive potential of Ni species is highly dependent on the ligand employed. Recently, we identified organometallic zirconaaziridine as an effective redox-transmetalating reagent in Ni catalysis, enabling two distinct applications: diastereoselectively modulable catalytic C(sp2)-glycosylation and the selective consecutive assembly of C(sp2) fragments at a methylene CH2 carbon. Notably, extensive experimental and computational studies support a sequential reduction mechanism, wherein oxidative addition of Ni(I)–X to C(sp2)–I, halide abstraction of C(sp3)–I by C(sp2)–Ni(I), and radical capture by C(sp2)–Ni(II) proceed with high selectivity. 1 Introduction 2 Redox-Transmetalation 3 Example 1: Diastereoselective C(sp2)-Glycosylation 4 Example 2: Consecutive Three-Component Cross-Electrophile Coupling 5 Summary