56846-74-3

Upstream product

• 82518-02-3 3-(2-phenyl-2-propyl)diazirine 
• 1375463-70-9 [(bpy)Pd^IV(CH₂CMe₂-o-C₆H₄)(F)(OTf)] 
• 1572949-23-5 [(bpy)Pd^IV(CH₂CMe₂-o-C₆H₄)(F)(NHTs)] 
• 7726-95-6 bromine 
• 7553-56-2 iodine 
• 2295-12-7 1,1-dimethylsilacyclobutane 
• 62171-59-9 1-(tert-butyl)-2-iodobenzene 
• 632326-71-7 (pyr)₂Ni(CH₂CMe₂-o-C₆H₄) 
• 1112-67-0 tetrabutyl-ammonium chloride 
• 74-88-4 methyl iodide 

Relevant academic research and scientific papers

Aerobic C-C and C-O bond formation reactions mediated by high-valent nickel species

Nickel complexes have been widely employed as catalysts in C-C and C-heteroatom bond formation reactions. While Ni(0), Ni(i), and Ni(ii) intermediates are most relevant in these transformations, recently Ni(iii) and Ni(iv) species have also been proposed to play a role in catalysis. Reported herein is the synthesis, detailed characterization, and reactivity of a series of Ni(ii) and Ni(iii) metallacycle complexes stabilized by tetradentate pyridinophane ligands with various N-substituents. Interestingly, while the oxidation of the Ni(ii) complexes with various other oxidants led to exclusive C-C bond formation in very good yields, the use of O2 or H2O2 as oxidants led to formation of appreciable amounts of C-O bond formation products, especially for the Ni(ii) complex supported by an asymmetric pyridinophane ligand containing one tosyl N-substituent. Moreover, cryo-ESI-MS studies support the formation of several high-valent Ni species as key intermediates in this uncommon Ni-mediated oxygenase-type chemistry.

Ring Expansion to 8-Membered Silacycles through Formal Cross-Dimerization of 5-Membered Palladacycles with Silacyclobutanes

Investigations of the sila-8-membered ring fused biaryls are of high significance for the discovery of new drug lead compounds. However, such compounds are still unknown due to the synthetic challenge. Herein, we describe the chemo- and regio-selective cr

Cycloneophylpalladium(IV) Complexes: Formation by Oxidative Addition and Selectivity of Their Reductive Elimination Reactions

The cycloneophylpalladium(II) complexes [Pd(CH2CMe2C6H4)(κ2-N,N′-L)] (L = RO(CH2)3N(CH2-2-C5H4N)2, R = H, Me) undergo oxidation to Pd(IV) with bromine or iodine to give [PdX(CH2CMe2C6H4)(κ3-N,N′,N″-L)]X (X = Br, I) or with methyl iodide to give the transient complexes [PdMe(CH2CMe2C6H4)(κ3-N,N′,N″-L)]I. The products of Br2 and I2 oxidation, [PdX(CH2CMe2C6H4)(κ3-N,N′,N″-L)]X (X = Br, I), are sufficiently stable to be isolated, but they decompose slowly in solution by reductive elimination to give the palladium(II) products [PdX(κ3-N,N′,N″-L)]X (X = Br, I). The organic products are formed via either CH2-Ar or CH2-X bond formation. In the latter case, neophyl rearrangement and protonolysis steps follow reductive elimination to give a mixture of organic products. The methylpalladium(IV) complexes [PdMe(CH2CMe2C6H4)(κ3-N,N′,N″-L)]I decompose at 0 °C by selective reductive elimination with Me-Ar bond coupling to give the alkylpalladium(II) complex [Pd(CH2CMe2-2-C6H4Me)(κ3-N,N′,N″-L)]I. The mechanisms of the reactions have been explored by kinetic studies.

Oxidative C-C bond formation reactivity of organometallic Ni(II), Ni(III), and Ni(IV) complexes

The use of the tridentate ligand 1,4,7-trimethyl-1,4,7-triazacyclononane (Me3tacn) and the cyclic alkyl/aryl C-donor ligand-CH2CMe2-o-C6H4-(cycloneophyl) allows for the synthesis of isolable organometallic NiII, NiIII, and NiIV complexes. Surprisingly, the fivecoordinate NiIII complex is stable both in solution and the solid state, and exhibits limited C-C bond formation reactivity. Oxidation by one electron of this NiIII species generates a six-coordinate NiIV complex, with an acetonitrile molecule bound to Ni. Interestingly, illumination of the NiIV complex with blue LEDs results in rapid formation of the cyclic C-C product at room temperature. This reactivity has important implications for the recently developed dual Ni/photoredox catalytic systems proposed to involve high-valent organometallic Ni intermediates. Additional reactivity studies show the corresponding NiII species undergoes oxidative addition with alkyl halides, as well as rapid oxidation by O2, to generate detectable NiIII and/or NiIV intermediates and followed by C-C bond formation.

Pd-Catalyzed C(sp3)-H Functionalization/Carbenoid Insertion: All-Carbon Quaternary Centers via Multiple C-C Bond Formation

A Pd-catalyzed C(sp3)-H functionalization/carbenoid insertion is described. The method allows for the rapid synthesis of bicyclic frameworks, generating all-carbon quaternary centers via multiple C-C bond formations in a straightforward manner.

Selective Oxygen Atom Insertion into an Aryl-Palladium Bond

The chemistry of a palladium(II) complex containing both an alkyl- and an aryl-palladium bond is reported. The reaction of [Pd(CH2CMe2C6H4)(MesN=CHCH=NMes)] with bromine or iodine leads to reductive elimination of 1,1-dimethylcyclobutabenzene with formation of [PdX2(MesN=CHCH=NMes)] (X = Br, I). However, the reaction with hydrogen peroxide gives [Pd(CH2CMe2C6H4O)(MesN=CHCH=NMes)] by overall oxygen atom insertion into the aryl-palladium rather than the alkyl-palladium bond. This complex [Pd(CH2CMe2C6H4O)(MesN=CHCH=NMes)] reacts with bromine, iodine, or hydrogen peroxide to give 3,3-dimethyl-2,3-dihydrobenzofuran and the corresponding complex [PdX2(MesN=CHCH=NMes)]. The mechanisms of reaction and basis for selectivity are discussed. The results support the view that oxygen atom insertion is a mechanistically viable pathway for selective catalytic oxidation of hydrocarbons by the green oxidant hydrogen peroxide.

C(sp3)-O bond-forming reductive elimination from PdIV with diverse oxygen nucleophiles

This article describes an investigation of C(sp3)-O bond-forming reductive elimination reactions from PdIV complexes. Phenoxide, acetate, difluoroacetate, dimethylphosphate, tosylate, and nitrate nucleophiles are shown to participate in this reaction. In all cases, C(sp3)-O bond formation occurs with high selectivity over potentially competing C(sp2)-O coupling. Additives have a profound impact on the chemoselectivity of these reductive elimination reactions. An excess of RO- was found to limit competing C(sp3)-C(sp2) bond-forming reductive elimination, while the presence of Lewis acidic cations was found to suppress competing C(sp3)-F coupling. Mechanistic investigations were conducted, and the available data are consistent with a sequence involving pre-equilibrium dissociation of the oxyanion ligand (RO-) followed by nucleophilic attack of RO- on a cationic PdIV-alkyl intermediate.

Competition between sp3-C-N vs sp3-C-F reductive elimination from PdIV complexes

This communication describes the design of a model system that allows direct investigation of competing sp3-C-N and sp3-C-F bond-forming reductive elimination from a PdIV fluoro sulfonamide complex. The reductive elimination selectivity varies dramatically as a function of reaction additives. A mechanism is proposed that provides a rationale for these effects.

THE EFFECTS OF MULTIPLICITY AND EXCITATION ON THE BEHAVIOR OF 2-METHYL-2-PHENYLPROPYLIDENE; THE INTRAMOLECULAR CHEMISTRY OF 2,2-DIPHENYLPROPYLIDENE

The intramolecular reactions of 2-methyl-2-phenylpropylidene and 2,2-diphenylpropylidene have been determined.