Palladium‐Catalyzed Suzuki–Miyaura Cross‐Coupling of Secondary α‐(Trifluoromethyl)benzyl Tosylates

A palladium‐catalyzed C(sp³)−C(sp²) Suzuki–Miyaura cross‐coupling of aryl boronic acids and α‐(trifluoromethyl)benzyl tosylates is reported. A readily available, air‐stable palladium catalyst was employed to access a wide range of functionalized 1,1‐diaryl‐2,2,2‐trifluoroethanes. Enantioenriched α‐(trifluoromethyl)benzyl tosylates were found to undergo cross‐coupling to give the corresponding enantioenriched cross‐coupled products with an overall inversion in configuration. The crucial role of the CF₃ group in promoting this transformation is demonstrated by comparison with non‐fluorinated derivatives.     

Catalytic C1 Alkylation with Methanol and Isotope‐Labeled Methanol

A metal‐catalyzed methylation process has been developed. By employing an air‐ and moisture‐stable manganese catalyst together with isotopically labeled methanol, a series of D‐, CD₃‐, and ¹³C‐labeled products were obtained in good yields under mild reaction conditions with water as the only byproduct.     

Synthesis and Reactivity of Paramagnetic Nickel Polypyridyl Complexes Relevant to C(sp2)–C(sp3)Coupling Reactions

A number of new transition metal catalyzed methods for the formation of C(sp²)–C(sp³) bonds have recently been described. These reactions often utilize bidentate polypyridyl‐ligated Ni catalysts, and paramagnetic Ni^I halide or aryl species are proposed in the catalytic cycles. However, there is little knowledge about complexes of this type. Here, we report the synthesis of paramagnetic bidentate polypyridyl‐ligated Ni halide and aryl complexes through elementary reactions proposed in catalytic cycles for C(sp²)–C(sp³) bond formation. We investigate the ability of these complexes to undergo organometallic reactions that are relevant to C(sp²)–C(sp³) coupling through stoichiometric studies and also explore their catalytic activity.     

Zirconium/Nickel‐Mediated One‐Pot Ketone Synthesis

A zirconium/nickel‐mediated one‐pot synthesis of ketones is reported. In the presence of Zn or Mn, Cp₂ZrCl₂ was found to dramatically accelerate the coupling and suppress side product formation via an I→SPy displacement at the same time. Unlike Zn/Pd‐ and Fe/Cu‐mediated one‐pot ketone syntheses, the new method is effective for nucleophiles bearing OR or equivalent functional groups at the α‐position. A mechanism comprising a nickel catalytic cycle, a zirconium catalytic cycle, and Zr→Ni transmetalation is proposed, and Cp₂ZrCl₂ and/or low‐valent Zr species are suggested to play crucial dual roles.