triflatecouples

Triflatecouples is a class of transition-metal-catalyzed cross-coupling reactions that use aryl or vinyl triflates (R–OTf) as electrophiles. The triflate group is a highly effective leaving group, enabling C–C bond formation from phenol- or enol-derived substrates and expanding cross-coupling beyond halides. The term encompasses Suzuki-Miyaura–type couplings and related processes with triflate electrophiles.

Most protocols rely on palladium or nickel catalysts. The catalytic cycle typically proceeds by oxidative addition of the metal into the C–OTf bond to give Ar–M(II)–OTf, followed by transmetalation with a nucleophilic partner (for example, a boronic acid in Suzuki couplings), and reductive elimination to yield the coupled product and regenerate the catalyst. Conditions vary with ligand, solvent, and base.

Triflate substrates are prepared from phenols by reaction with triflic anhydride and a base, and vinyl triflates can be formed from enolizable substrates. Aryl triflates often show high reactivity, at times surpassing aryl chlorides or bromides, though performance depends on substrate electronics and the catalytic system.

Advantages include access to biaryl motifs from readily available phenols and broad functional-group compatibility. Limitations include moisture sensitivity, potential hydrolysis of the triflate, and the need for specialized ligands or higher temperatures for challenging substrates. Triflate couplings complement halide cross-couplings and extend synthetic options for complex molecules.

Applications span pharmaceuticals, natural-product synthesis, and materials science, especially for late-stage diversification and construction of densely substituted arenes and alkenes.