Complementary regioselectivity in the Cu(I)-catalyzed diamination of conjugated dienes to form cyclic sulfamides

This paper describes the regioselective diamination of conjugated dienes using inexpensive Cu(I) as catalyst and N,N-di-tert-butylthiadiaziridine 1,1-dioxide as nitrogen source. The regioselectivity of diamination is likely due to dual mechanistic pathways which are greatly influenced by reaction conditions and the nature of the diene. A variety of useful internal and terminal cyclic sulfamides can be obtained in good yield.     

Cu(I)-catalyzed asymmetric diamination of conjugated dienes

A Cu(I)-catalyzed asymmetric diamination for a variety of conjugated dienes and a triene with encouraging ee's has been effectively achieved using (R)-DTBM-SEGPHOS as a chiral ligand and di- tert-butyldiaziridinone as the nitrogen source.     

Cu(I)-catalyzed cycloguanidination of olefins

This paper describes a novel cycloguanidination process using CuCl as catalyst and diaziridinimines as the nitrogen source. A variety of conjugated dienes, trienes, and terminal olefins can be effectively diaminated under mild reaction conditions. For dienes and trienes, the reaction occurs at the terminal double bond with high regioselectivity.     

A mild Cu(I)-catalyzed regioselective diamination of conjugated dienes

This paper describes a novel diamination process that uses CuCl as catalyst and di-tert-butyldiaziridinone as nitrogen source. A wide variety of conjugated dienes and a triene can be effectively diaminated in good yields with generally high regioselectivity under mild reaction conditions.     

NO双分子在Cu2O(111)面吸附与解离的理论研究

采用广义梯度密度泛函理论结合周期平板模型方法, 在DNP基组下, 研究了NO双分子在三重态和单重态两种电子组态下在Cu2O(111)完整表面的吸附情况. 考虑了Cu+(NO)(NO)、Cu+(NO)(ON)及Cu+(ON)(ON)这三种构型, 计算了它们的吸附能和Mulliken电荷, 分析并预测了吸附后可能产生的物种. 结果表明, 当两个NO分子都以O端吸附在Cu2O(111)表面时即Cu+(ON)(ON)构型, N—N键长很短, 只有124.4 pm, 吸附的两个NO分子形成了二聚体形式, 这种吸附构型有利于进一步离解产生N2或N2O并形成Cu-O表面物种.     

Cu(I)-catalyzed hetero-Diels-Alder reaction between Danishefsky-type siloxy dienes and ketones

A general catalytic method for the hetero-Diels-Alder reaction between Danishefsky-type siloxy dienes and ketones was developed. Optimum results were produced with a catalyst generated from CuOTf x (C6H6)1/2 and TBAT with Ph 3PO as the catalytic additive. This reaction was extended to an asymmetric variant, using a Cu(I)-Walphos catalyst.     

Iodine(III)-Promoted Intermolecular Diamination of Alkenes

A rapid and productive vicinal diamination of alkenes takes place in the presence of a hypervalent iodine(III) reagent and bissulfonimides as nitrogen sources. A total of more than 60 examples are presented. The reaction is characterized by its robustness and its wide substrate scope: it proceeds selectively with both terminal and internal alkenes and tolerates a range of functional groups.     

Hydrosilylation of a dinuclear tantalum dinitrogen complex: cleavage of N2 and functionalization of both nitrogen atoms

Hydrosilylation of the ditantalum dinitrogen complex ([NPN]Ta)2(mu-H)2(mu-eta1:eta2-N2) proceeds via an addition reaction to produce ([NPN]TaH)(mu-H)2(mu-eta1:eta2-N-NSiH2Bu)(Ta[NPN]), which contains a new N-Si bond and a terminal tantalum hydride; this species has been characterized by NMR spectroscopy and X-ray diffraction. This complex undergoes reductive elimination of H2 followed by N-N bond cleavage to generate a new intermediate with the formula ([NPN]TaH)(mu-N)(mu-NSiH2Bu)(Ta[NPN]); confirmation of N-N bond cleavage is evident from the 15N-labeled isotopomer that displays an absence of 15N-15N scalar coupling in the 15N NMR spectrum. In the presence of additional silane, a second hydrosilylation and reductive elimination results to give ([NPN]Ta)2(mu-NSiH2Bu)2, a species in which each dinitrogen-derived N atom has been converted to a bridging silylimide ligand. This latter complex displays C2h symmetry both in solution and in the solid state.     

双膦Cu及不对称Pd催化剂的结构及其对烯烃-一氧化碳完全交替共聚的催化性能

 配体及配合物的结构对催化烯烃-CO完全交替共聚反应活性及稳定性具有重要的影响. IR和XPS实验结果表明,5-硝基-1,10-菲咯啉的钯配合物催化苯乙烯-CO共聚的高活性与其结构的不对称性有关; 揭示了廉价的Cu金属双膦螯合物作为新型乙烯-CO交替共聚催化剂具有一定的可行性,探讨了配合物结构对烯烃-CO共聚反应活性及稳定性的影响,同时通过IR,1H NMR和13C NMR确认了所得交替共聚物聚酮的结构.     

Carbon monoxide-induced N-N bond cleavage of nitrous oxide that is competitive with oxygen atom transfer to carbon monoxide as mediated by a Mo(II)/Mo(IV) catalytic cycle

In the presence of CO, facile N-N bond cleavage of N(2)O occurs at the formal Mo(II) center within coordinatively unsaturated mononuclear species derived from Cp*Mo[N((i)Pr)C(Me)N((i)Pr)](CO)(2) (Cp* = η(5)-C(5)Me(5)) (1) and {Cp*Mo[N((i)Pr)C(Me)N((i)Pr)]}(2)(μ-η(1):η(1)-N(2)) (9) under photolytic and dark conditions, respectively, to produce the nitrosyl, isocyanate complex Cp*Mo[N((i)Pr)C(Me)N((i)Pr)](κ-N-NO)(κ-N-NCO) (7). Competitive N-O bond cleavage of N(2)O proceeds under the same conditions to yield the Mo(IV) terminal metal oxo complex Cp*Mo[N((i)Pr)C(Me)N((i)Pr)](O) (3), which can be recycled to produce more 7 through oxygen-atom-transfer oxidation of CO to produce CO(2).     

Electrochemistry of the system Cu(II)Cu(I)Cu(0) in acidified thiocyanate solutions

The system Cu(II)Cu(I)Cu(0) in acidified thiocyanate medium was investigated at carbon, mercury, and copper amalgam electrodes using cyclic voltammetry, normal, differential and reverse pulse voltammetry, double potential step chronocoulometry, and exhaustive coulometry. Reduction of Cu(II) to Cu(I) on carbon electrodes proceeds quasireversibly. At moderate concentrations of Cu(II) and SCN^? the reduction of Cu(II) leads to three-dimensional precipitation of CuSCN which can be deposited at the electrode surface. At high concentration of SCN^? complexation dominates over precipitation and only soluble species are formed. At mercury and copper amalgam electrodes the situation is more complicated. The three- dimensional precipitation is preceded by strong thiocyanate-induced adsorption of Cu(I) which results in formation of a mono layer at potential well-separated from those where diffusing product is formed.     

Diamination of conjugated dienes and trienes catalyzed by N-heterocyclic carbene-pd(0) complexes

This paper describes a diamination process using di-t-butyldiaziridinone as nitrogen source and N-heterocyclic carbene-Pd(0) complex as catalyst. A wide variety of conjugated dienes and trienes can be effectively diaminated in good yields with high regio- and stereoselectivities.     

Cu(I)-catalyzed intermolecular diamination of activated terminal olefins

This paper describes a novel intermolecular diamination process with CuCl as catalyst and di-tert-butylthiadiaziridine 1,1-dioxide as nitrogen source. A variety of activated terminal olefins can be effectively diaminated in good yields under mild reaction conditions.     

Unsupported gold(I)-copper(I) interactions through eta1 Au-[Au(C6F5)2]- coordination to Cu+ Lewis acid sites

The reaction of the complex [Au2Ag2(C6F5)4)N[triple bond]CCH3)2]n (1) with 1 equiv of CuCl in the presence of 1 equiv of pyrimidine ligand leads to the formation of the heteronuclear Au(I)-Cu(I) organometallic polymer [Cu{Au(C6F5)2}(N[triple bond]CCH3)(mu2-C4H4N2)]n (2) through a transmetalation reaction. Complex 2 displays unprecedented unsupported Au(I)...Cu(I) interactions of [Au(C6F5)2]- units with the acid Cu(I) sites in a [Cu(N[triple bond]CCH3)(mu2-pyrimidine)]n+(n) polymeric chain. Complex 2 has a rich photophysics in solution and in the solid state.     

The radical mechanism of cobalt(II) porphyrin-catalyzed olefin aziridination and the importance of cooperative H-bonding

The mechanism of cobalt(II) porphyrin-mediated aziridination of styrene with PhSO(2)N(3) was studied by means of DFT calculations. The computations clearly indicate the involvement of a cobalt 'nitrene radical' intermediate in the Co(II)(por)-catalyzed alkene aziridination. The addition of styrene to this species proceeds in a stepwise fashion via radical addition of the 'nitrene radical'C to the C=C double bond of styrene to form a γ-alkyl radical intermediate D. The thus formed tri-radical species D easily collapses in an almost barrierless ring closure reaction (TS3) to form the aziridine, thereby regenerating the cobalt(II) porphyrin catalyst. The radical addition of the 'nitrene radical'C to the olefin (TS2) proceeds with a comparable barrier as its formation (TS1), thus providing a good explanation for the first order kinetics in both substrates and the catalyst observed experimentally. Formation of C is clearly accelerated by stabilization of C and TS1 via hydrogen bonding between the S=O and N-H units. The computed radical-type mechanism agrees well with all available mechanistic and kinetic information. The computed free energy profile readily explains the superior performance of the Co(II)(porAmide) system with H-bond donor functionalities over the non-functionalized Co(TPP).     

Cu(I) luminescence from the tetranuclear Cu4S4 cofactor of a synthetic 4-helix bundle

The addition of Cu(I) to the random-coil peptide, C16C19-GGY, produces a self-organized, metal-bridged 4-helix bundle which displays an intense room-temperature luminescence at 600 nm. Emission, UV, and CD titrations along with X-ray absorption studies indicate that the luminescent cofactor is likely a Cu4S4 cluster in which each Cu atom is bridged by the side chains of two cysteine residues and has terminal N/O ligation.     

Cu(I)-mediated reductive amination of boronic acids with nitroso aromatics

[reaction: see text] A mild method for the reductive amination of aryl boronic acids with nitroso aromatic compounds is reported. This C-N bond formation is mediated by a stoichiometric amount of CuCl as both a catalyst and a reducing agent. Alternatively, 10% Cu(I)-3-methylsalicylate (CuMeSal) catalyzes the same reaction in the presence of either ascorbic acid or hydroquinone as the terminal reducing agent. Diarylamines bearing a variety of functional groups can be obtained in good yields.     

Oxidative Interception of the Hydroamination Pathway: A Gold‐Catalyzed Diamination of Alkenes

A complimentary diamination of alkenes by using homogeneous gold catalysts is described. The reaction is one of very few examples of homogeneous gold oxidation catalysis and proceeds with high selectivity under mild conditions. Individual steps of the suggested catalytic cycle were investigated on isolated model gold complexes, and new pathways for gold‐catalyzed amination reactions were established. The key step is an intramolecular alkyl–nitrogen bond formation from a gold(III) intermediate. This process validates the concept of reductive elimination from high oxidation catalyst states for this type of C? N bond forming reactions.     

Cu(I)-amido complexes in the Ullmann reaction: reactions of Cu(I)-amido complexes with iodoarenes with and without autocatalysis by CuI

A series of Cu(I)-amido complexes both lacking ancillary ligands and containing 1,10-phenanthroline (phen) as ancillary ligand have been prepared. These complexes react with iodoarenes to form arylamine products, and this reactivity is consistent with the intermediacy of such complexes in catalytic Ullmann amination reactions. The stoichiometric reactions of the Cu(I)-amido complexes with iodoarenes are autocatalytic, with the free CuI generated during the reaction serving as the catalyst. Such autocatalytic behavior was not observed for reactions of iodoarenes with copper(I) amidates, imidates, or phenoxides. The selectivity of these complexes for two sterically distinct aryl halides under various conditions imply that the autocatalytic reaction proceeds by forming highly reactive [CuNPh(2)](n) lacking phen. Reactions with radical probes imply that the reactions of phen-ligated Cu(I)-amido complexes with iodoarenes occur without the intermediacy of aryl radicals. Density functional theory calculations on the oxidative addition of iodoarenes to Cu(I) species are consistent with faster reactions of iodoarenes with CuNPh(2) species lacking phen in DMSO than reactions of iodoarenes with LCuNPh(2) in which L = phen. The free-energy barrier computed for the reaction of PhI with (DMSO)CuNPh(2) was 21.8 kcal/mol, while that for the reaction of PhI with (phen)CuNPh(2) was 33.4 kcal/mol.     

Heterobimetallic activation of dioxygen: characterization and reactivity of novel Cu(I)-Ge(II) complexes

Reaction of the known germylene Ge[N(SiMe3)2]2 and a new heterocyclic variant Ge[(NMes)2(CH)2] with [L(Me2)Cu]2 (L(Me2) = the beta-diketiminate derived from 2-(2,6-dimethylphenyl)amino-4-(2,6-dimethylphenyl)imino-2-pentene) yielded novel Cu(I)-Ge(II) complexes L(Me2)Cu-Ge[(NMes)2(CH)2] (1a) and L(Me2)Cu-Ge[N(SiMe3)2]2 (1b), which were characterized by spectroscopy and X-ray crystallography. The lability of the Cu(I)-Ge(II) bond in 1a and b was probed by studies of their reactivity with benzil, PPh3, and a N-heterocyclic carbene (NHC). Notably, both complexes are cleaved rapidly by PPh3 and the NHC to yield stable Cu(I) adducts (characterized by X-ray diffraction) and the free germylene. In addition, the complexes are highly reactive with O2 and exhibit chemistry which depends on the bound germylene. Thus, oxygenation of 1a results in scission and formation of thermally unstable L(Me2)CuO2, which subsequently decays to [(L(Me2)Cu)2(mu-O)2], while 1b yields L(Me2)Cu(mu-O)2Ge[N(SiMe3)2]2, a novel heterobimetallic intermediate having a [Cu(III)(mu-O)2Ge(IV)]3+ core. The isolation of the latter species by direct oxygenation of a Cu(I)-Ge(II) precursor represents a new route to heterobimetallic oxidants comprising copper.