The selective difluoromethylene insertion into a C–Cu bond is a challenging task and is currently limited to either a single CF2 insertion into CuCF3 or double CF2 insertions into CuC6F5 (or (Z)-CF3CF = CFCu). Achieving both selective single and double CF2 insertions into the same C–Cu bond is even more difficult. Herein, highly controllable single and double CF2 insertions into CuCF2H species with a TMSCF2Br reagent have been described, affording two previously unknown fluoroalkylcopper species “Cu­(CF2)nCF2H” (n = 1 and 2) independently under different reaction conditions. This work represents the first example of both single and double CF2 insertions into the same C–Cu bond in a highly selective manner. The synthetic value of the obtained “Cu­(CF2) n CF2H” (n = 1 and 2) species is demonstrated by their reactions with aryl iodides, halogenation agents, and cinnamyl chloride, which enables the direct transfer of HCF2CF2 and HCF2CF2CF2 moieties into organic molecules. The key to controllable fluorocarbon chain elongation from C1 to C2 and from C1 to C3 is presumably attributed to the different reactivities of “Cu­(CF2) n CF2H” species (n = 0, 1, 2 and 3) and the loading of the TMSCF2Br reagent.

A mild and operationally simple copper-catalyzed vinylogous aerobic oxidation of β,γ- and α,β-unsaturated esters is described. This method features good yields, broad substrate scope, excellent chemo- and regioselectivity, and good functional group tolerance. This method is additionally capable of oxidizing β,γ- and α,β-unsaturated aldehydes, ketones, amides, nitriles, and sulfones. Furthermore, the present catalytic system is suitable for bisvinylogous and trisvinylogous oxidation. Tetramethylguanidine (TMG) was found to be crucial in its role as a base, but we also speculate that it serves as a ligand to copper(II) triflate to produce the active copper(II) catalyst. Mechanistic experiments conducted suggest a plausible reaction pathway via an allylcopper(II) species. Finally, the breadth of scope and power of this methodology are demonstrated through its application to complex natural product substrates.

A Cu-catalyzed gem-bis(trifluoromethyl)olefination of a-diazo esters, using TMSCF 3 as the only fluorocarbon source, has been developed and provides an exquisite method to access gem-bis(trifluoromethyl)alkenes. This unprecedented olefination process involves a carbene migratory insertion into "CuCF 3 " to generate the a-CF 3 -substituted organocopper species, which then undergoes b-fluoride elimination and two consecutive addition-elimination processes to give the desired products. The key to this efficient one-pot C 1 -to-C 3 synthetic protocol lies in the controllable double (over single and triple) trifluoromethylations of the gem-difluoroalkene intermediates.

TMSCF3-derived CuCF2CF3 species has been successfully applied in pentafluoroethylation of organobronates and terminal alkynes. By using 1,10-phenanthroline as ligand, a broad range of (hetero)arylboronates and alkenylboronates were smoothly pentafluoroethylated under...

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A Cu‐catalyzed gem‐bis(trifluoromethyl)olefination of α‐diazo esters, using TMSCF3 as the only fluorocarbon source, has been developed and provides an exquisite method to access gem‐bis(trifluoromethyl)alkenes. This unprecedented olefination process involves a carbene migratory insertion into “CuCF3” to generate the α‐CF3‐substituted organocopper species, which then undergoes β‐fluoride elimination and two consecutive addition‐elimination processes to give the desired products. The key to this efficient one‐pot C1‐to‐C3 synthetic protocol lies in the controllable double (over single and triple) trifluoromethylations of the gem‐difluoroalkene intermediates.