The preparation of copper(II) and copper(I) salts in acetonitrile using group VA and VB pentafluorides

Understanding the Fate of the Oxyallyl Cation following Nazarov Electrocyclization: Sequential Wagner−Meerwein Migrations and the Synthesis of Spirocyclic Cyclopentenones

“…In our laboratory, previous studies have shown that the complex [Cu(II)-Box](OTf) 2 6 was particularly efficient for the enantioselective Nazarov cyclization. 27 Higher enantiomeric excess was obtained when a higher catalyst loading (one equivalent) was used, but 3a was not formed (Table 4, entry 1). Complex 7 (with a perchlorate counterion), did provide rearranged product 3a , in a ratio 1.2:1 with the Nazarov product 2a (entry 2).…”

Copper(I) hexafluoroantimonate – an example of a compound with CuI in a solely fluorine environment

“…The most investigated solvent in Cu I /Cu II ÀMF 5 (M = P, As, Sb, Nb, Ta, Mo, W or U) system is acetonitrile (CH 3 CN) [11][12][13][14][15][16][17][18]. The Cu II /Cu I cations are solvated by CH 3 CN as in solution as in isolated products.…”

“…Cu(SbF 6 ) 2 is very soluble (>3.0 mol l À1 ); CuAsF 6 ($0.5 mol l À1 ) is more soluble than CuSbF 6 ($0.05 mol l À1 ). This is the reverse of the situation in CH 3 CN, where Cu II salts of [PF 6 ] À and [TaF 6 ] À are less soluble than corresponding Cu I salts [16].…”

“…; X À = [PF 6 ] À , [AsF 6 ] À , [MoF 6 ] À , [UF 6 ] À , [BF 4 ] À , etc.) [11][12][13][14][15][16][17][18] are not included, because in their case Cu I is coordinated by organic ligands and expected to be well separated from fluorine containing anions (X À ).…”

“…Proposed mechanism is in agreement with previous investigations, where it was found that CuF 2 first reacts with the pentafluorides in acetonitrile (CH 3 CN) to give solvated Cu II , hexafluoroanion salts. These react with Cu metal to give the corresponding Cu I compounds [16].…”