Copper-Mediated -CF(OCF)(CFH) Transfer to Organic Electrophiles.

The integration of fluorine into medicinal compounds has become a widely used strategy to improve the biochemical and therapeutic properties of drugs. Inclusion of -CFH and -OCF fluoroalkyl groups has garnered attention due to their bioisosteric properties, enhanced lipophilicity, and potential hydrogen-bonding capability in bioactive substances. In this study, we prepared a series of stable Cu[CF(OCF)(CFH)]L complexes by insertion of commercially available perfluoro(methyl vinyl ether), CF=CF(OCF), into Cu-H bonds derived from Stryker's reagent, [CuH(PPh)], using ancillary ligands L.

Balancing Reactivity, Regioselectivity, and Product Stability in Ir-Catalyzed Ortho-C-H Borylations of Anilines by Modulating the Diboron Partner.

Ir-catalyzed arene C-H borylations (CHB) of anilines can be highly ortho selective by using a small Beg (eg = ethane-1,2-diol) as the borylating reagent. Unfortunately, the products are prone to decomposition, and transesterification with pinacol is required prior to isolation. This work offers a solution by adjusting the size of the diboron reagent.

A Hydrazone Ligand for Iridium-Catalyzed C-H Borylation: Enhanced Reactivity and Selectivity for Fluorinated Arenes.

Ir-catalyzed C-H borylations of fluorinated and cyanated arenes with high -to-F/CN are described. Use of a dipyridyl hydrazone framework as the ancillary ligand and pinacolborane (HBpin) as the functionalizing reagent generates catalysts that are significantly more active selective than 4,4'-di--butyl-2,2'-bipyridine (dtbpy) for both electron-deficient and electron-rich substrates. Investigation of the ligand framework resulted in the observation of formal -borylation of the hydrazone by HBpin, as evidenced by NMR spectroscopy and X-ray crystallography.

Nickel-Catalyzed Homologation of Vinylidene Difluoride (CH═CF): Selective β-F β-H Elimination.

Hydrofluoroolefins (HFOs) constitute the newest generation of fluorocarbon refrigerants and foam-blowing agents due to their reduced global warming potential their saturated analogues. To identify new synthetic routes to HFOs, we show that reactions of bulky Ni(0) phosphine and -NHC complexes with vinylidene difluoride (VF2) afford μ-fluoro-1,1,3-trifluorobut-3-enyl Ni complexes. Moreover, addition of triisopropylsilane allows for reductive elimination of the reduced product─2,4,4-trifluoro-1-butene─demonstrating the Ni-catalyzed hydrodefluorodimerization of VF2.

Silica-Supported Mn Sites as Efficient Catalysts for Carbonyl Hydroboration, Hydrosilylation, and Transesterification.

Manganese, the third most abundant transition-metal element after iron and titanium, has recently been demonstrated to be an effective homogeneous catalyst in numerous reactions. Herein, the preparation of silica-supported Mn sites is reported using Surface Organometallic Chemistry (SOMC), combined with tailored thermolytic molecular precursors approach based on Mn [OSi(OtBu) ] and Mn{N(SiMe ) } ⋅THF. These supported Mn sites, free of organic ligands, efficiently catalyze numerous reactions: hydroboration and hydrosilylation of ketones and aldehydes as well as the transesterification of industrially relevant substrates.

Selective hydrogenation of α,β-unsaturated carbonyl compounds on silica-supported copper nanoparticles.

Silica-supported copper nanoparticles prepared via surface organometallic chemistry are highly efficient for the selective hydrogenation of various α,β-unsaturated carbonyl compounds yielding the corresponding saturated esters, ketones, and aldehydes in the absence of additives. High conversions and selectivities (>99%) are obtained for most substrates upon hydrogenation at 100-150 °C and under 25 bar of H2.

Spin-Doctoring Cobalt Redox Shuttles for Dye-Sensitized Solar Cells.

A new low-spin (LS) cobalt(II) outer-sphere redox shuttle (OSRS) [Co(PY5Me)(CN)], where PY5Me represents the pentadentate ligand 2,6-bis(1,1-bis(2-pyridyl)ethyl)pyridine, has been synthesized and characterized for its potential application in dye-sensitized solar cells (DSSCs). Introduction of the strong field CN ligand into the open axial coordination site forced the cobalt(II) complex, [Co(PY5Me)(CN)], to become LS based upon the complex's magnetic susceptibility (1.91 ± 0.

Achieving High Ortho Selectivity in Aniline C-H Borylations by Modifying Boron Substituents.

High ortho selectivity for Ir-catalyzed C-H borylations (CHBs) of anilines results when Beg (eg = ethylene glycolate) is used as the borylating reagent in lieu of Bpin, which is known to give isomeric mixtures with anilines lacking a blocking group at the 4-position. With this modification, high selectivities and good yields are now possible for various anilines, including those with groups at the 2- and 3-positions. Experiments indicate that ArylN(H)Beg species are generated prior to CHB and support the improved ortho selectivity relative to Bpin reactions arising from smaller Beg ligands on the Ir catalyst.

Reversible Borylene Formation from Ring Opening of Pinacolborane and Other Intermediates Generated from Five-Coordinate Tris-Boryl Complexes: Implications for Catalytic C-H Borylation.

Catalytic C-H borylation using the five-coordinate tris-boryl complex (dippe)Ir(Bpin) (, dippe = 1,2-bis(diisopropylphosphino)ethane) has been examined using P{H} and H NMR spectroscopy. Compound was shown to react rapidly and reversibly with HBpin to generate a six-coordinate borylene complex, (dippe)Ir(H)-(Bpin)(BOCMeCMeOBpin) (), whose structure was confirmed by X-ray crystallography. Under catalytic conditions, the H generated from C-H borylation converted compound to a series of intermediates.

Silyl phosphorus and nitrogen donor chelates for homogeneous ortho borylation catalysis.

Ir catalysts supported by bidentate silyl ligands that contain P- or N-donors are shown to effect ortho borylations for a range of substituted aromatics. The substrate scope is broad, and the modular ligand synthesis allows for flexible catalyst design.

High-throughput optimization of Ir-catalyzed C-H borylation: a tutorial for practical applications.

With the aid of high-throughput screening, the efficiency of Ir-catalyzed C-H borylations has been assessed as functions of precatalyst, boron reagent, ligand, order of addition, temperature, solvent, and substrate. This study not only validated some accepted practices but also uncovered unconventional conditions that were key to substrate performance. We anticipate that insights drawn from these findings will be used to design reaction conditions for substrates whose borylations are difficult to impossible using standard catalytic conditions.