Rhodium Derivatives of Peroxoboronic Acids and Peroxoboric Acid: Formation of Metallatrioxaborolanes from an η²‐Peroxo Complex

A Rhodium Peroxido Complex in Mono‐, Di‐, and Peroxygenation Reactions

“…The stabilizing properties of the perfluorinated pyridyl ligand may play a certain role in this context. [7,9,16] The 19 F NMR spectrum of 1 a consists of three signals (ratio: 2:1:1) for the tetrafluoropyridyl ligand, which indicate hindered rotation about the rhodium-carbon bond. Formation of a rhodium(III) complex is evidenced by a rhodiumphosphorus coupling constant of 82 Hz for the signal at d = 28.8 ppm in the 31 P{ 1 H} NMR spectrum and by an absorption band at 2026 cm À1 in the IR spectrum, which can be assigned to the CO stretching vibration.…”

“…[7] Examples of transfer of both oxygen atoms from a transition metal peroxido complex to a substrate are sparse, [8] and formation of peroxides is relatively seldom. The complexes [M(O)(O 2 ) 2 (py)] (M = Cr, Mo; py = pyridine) react with electron-rich enol ethers to yield the corresponding dioxetanes, [8a] but the products are formed by two consecutive mono-oxygenation reactions and involve intermediate formation of the corresponding epoxides.…”

A Highly Reactive Rhodium(I)–Boryl Complex as a Useful Tool for CH Bond Activation and Catalytic CF Bond Borylation

“…[11,12] Treatment of the chloro complex [Rh(Cl)-(PEt 3 ) 3 ] (1) with NaOPh gave the rhodium phenoxide [Rh-(OPh)(PEt 3 ) 3 ] (2; Scheme 1). [11,12] Treatment of the chloro complex [Rh(Cl)-(PEt 3 ) 3 ] (1) with NaOPh gave the rhodium phenoxide [Rh-(OPh)(PEt 3 ) 3 ] (2; Scheme 1).…”

“…Moreover, we found that 3 can be generated in a comparable reaction, starting from the fluoro compound [Rh(F)(PEt 3 ) 3 ] (4). [12,13] A second resonance at d = 9.1 ppm, with a coupling to rhodium of 110 Hz, can be assigned to the phosphorus ligand that is in the position trans to the Bpin group. Note that boryl complex 3 does not react with another equivalent of B 2 pin 2 to give a Rh III complex that would be comparable to fac-[Rh(Bcat) 3 (PMe 3 ) 3 ].…”

“…The 31 P NMR spectrum at 203 K exhibits a signal at d = 20.5 ppm for the phosphine atoms that are in a mutually trans position. [12] The relatively small coupling constant of 75 Hz suggests that the two equivalent phosphine ligands are located trans to the boryl ligands. [12,13] A second resonance at d = 9.1 ppm, with a coupling to rhodium of 110 Hz, can be assigned to the phosphorus ligand that is in the position trans to the Bpin group.…”