PhI(OAc)2‐Mediated Radical Trifluoromethylation of Vinyl Azides with Me3SiCF3

The fluorine‐containing organic motif is becoming privileged in pharmaceuticals, agrochemicals, and functional materials, owing to its unique properties such as electron‐withdrawing character, metabolic stability, and lipophilicity. Described herein is the PhI(OAc)₂‐mediated radical trifluoromethylation of vinyl azides with Me₃SiCF₃ to efficiently generate α‐trifluoromethyl azines. The resulting α‐trifluoromethyl azines were successfully transformed to valuable fluorine‐containing molecules such as α‐trifluoromethyl ketones, β‐trifluoromethyl amines, 5‐fluoropyrazoles, and trifluoroethyl isoquinolines.     

RbBa2(N3)5: a new ternary azide

Rubidium dibarium penta­azide, RbBa₂(N₃)₅, was prepared from an aqueous solution of the binary azides at room temperature. It crystallizes in the monoclinic system (space group P2/n). Two central atoms of azide groups occupy the 2c () and 2b () positions, another azide group lies completely on a twofold axis (2f), while Rb atoms are situated in 2e (2) positions. The crystal structure of RbBa₂(N₃)₅ can be regarded as a distorted AlB₂‐type arrangement of the metal atoms, with the azide groups occupying the voids between the cations. This results in coordination numbers of 8 (Rb) and 10 (Ba). The N—N distances are in the range 1.169 (8)–1.190 (5) Å, typical for the azide group.     

Rh2(OAc)4-PPh3 as a catalyst for the liquid-phase dehydrogenation of 2-propanol

The most active homogeneous catalyst hitherto known for the selective dehydrogenation of 2-propanol has been found to form from Rh2(OAc)4 by adding PPh₃ in situ, although Rh₂(OAc)₄ itself possesses no catalytic activity. From the reaction solution a complex was isolated, ³¹P(¹H) NMR of which showed that coordination of PPh₃ occurs not only to the axial but also to the equatorial positions of the Rh-Rh axis. When this complex is used as a catalyst with PPh₃ and acetic acid present, no induction period was observed, which appears for the catalyst generated in situ. Drastic changes in catalytic properties occurred by replacing Rh₂(OAc)₄ with Rh₂(OCOCF₃)₄ or PPh₃ with P(OPh)₃, which indicate prospects of tailor-making the catalyst.     

双膦钌配合物Ru（OAc）2（Ph3P）（dppm）和Ru（OAc）2（dppm）2的合成和催化性能

合成了双膦醋酸钌合作物，不同温度的＾１Ｈ ＮＭＲ谱表明，两个醋酸根分别以单齿和双齿配体与中心钌（Ⅱ）配位；＾３１Ｐ ＮＭＲ和Ｘ－射线结构分析表明膦配体为面式构型。配合物对丙烯酸和苯乙烯有选择氢化活性。     

Radical products of the oxidation of 2,2-diacyl-1-arylhydrazines with the system Pb(OAc)4-CF3COOH-CH2Cl2

Summary The oxidation of 2,2-Diacyl-1-arylhydrazines1a–l with the system Pb(OAc)₄-CF₃COOH-CH₂Cl₂ led to the formation of two types of radical products. Phenazinium cation radicals5a–h were formed from 2,2-diacyl-1-arylhydrazines1a–h, while hydrazyl radicals2i–l were observed to be the only radical products of the oxidation of1i–l. The generated radicals are characterized by their EPR parameters.

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Radikalische Produkte der Oxidation von 2,2-Diacyl-1-arylhydrazinen mit dem System Pb(OAc)₄-CF₃COOH-CH₂Cl₂

Zusammenfassung Die Oxidation der 2,2-Diacyl-1-arylhydrazine1a–l mit dem System Pb(OAc)₄-CF₃COOH-CH₂Cl₂ führte zu zwei unterschiedlichen Typen von Radikalen. Aus den 2,2-Diacyl-1-arylhydrazinen1a–h werden die Phenaziniumkationenradikale5a–h gebildet, während nach Oxidation von1i–l die entsprechenden Hydrazyle2i–l als einzige Radikalprodukte nachweisbar waren. Die erzeugten Radikale wurden durch ihre EPR-Parameter charakterisiert.

     

Ga(OTf)_3催化的3-羟基氧化吲哚与TMSN_3的取代反应研究

研究实现了首例3-羟基氧化吲哚1与TMSN3的取代反应,为胺基季碳氧化吲哚的合成提供了一种新方法.在使用Ga(OTf)3作为催化剂和乙腈作为溶剂的条件下,一系列具有不同取代基的3-羟基氧化吲哚均可与TMSN3高效地反应生成相应的3-叠氮基取代的季碳氧化吲哚,且催化剂用量可降低到1 mol%.产物可通过催化氢化方便地转化成相应的胺基季碳氧化吲哚.     

双膦钌配合物Ru（OAc）_2（Ph_3P）（dppm）和Ru（OAc）_2（

合成了双膦醋酸钌配合物，不同温度的￣１ＨＮＭＲ谱表明，两个醋酸根分别以单齿和双齿配体与中心钌（Ⅱ）配位；￣（３１）ＰＮＭＲ和Ｘ－射线结构分析表明膦配体为面式构型。配合物对丙烯酸和苯乙烯有选择氢化活性。     

Ligand-free Heck reaction: Pd(OAc)2 as an active catalyst revisited

Palladium acetate was shown to be an extremely active catalyst for the Heck reaction of aryl bromides. Both the base and the solvent were found to have a fundamental influence on the efficiency of the reaction, with K(3)PO(4) and N,N-dimethylacetamide being the optimal base and solvent, respectively.     

A candidate for a single‐chain magnet: [Mn3(OAc)6(py)2(H2O)2]n (OAc is acetate and py is pyridine)

The title complex, catena‐poly[di‐μ₃‐acetato‐κ⁶O:O:O′‐tetra‐μ₂‐acetato‐κ⁴O:O;κ⁴O:O′‐diaquabis(pyridine‐κN)trimanganese(II)], [Mn₃(CH₃COO)₆(C₆H₅N)₂(H₂O)₂]_n, is a true one‐dimensional coordination polymer, in which the Mn^II centres form a zigzag chain along [010]. The asymmetric unit contains two metal centres, one of which (Mn1) lies on an inversion centre, while the other (Mn2) is placed close to an inversion centre on a general position. Since all the acetates behave as bridging ligands, although with different μ₂‐ and μ₃‐coordination modes, a one‐dimensional polymeric structure is formed, based on trinuclear repeat units (Mn1...Mn2...Mn2′), in which the Mn2 and Mn2′ sites are related by an inversion centre. Within this monomeric block, the metal–metal separations are Mn1...Mn2 = 3.36180 (18) Å and Mn2...Mn2′ = 4.4804 (3) Å. Cation Mn1, located on an inversion centre, displays an [MnO₆] coordination sphere, while Mn2, on a general position, has a slightly stronger [MnO₅N] ligand field, as the sixth coordination site is occupied by a pyridine molecule. Both centres approximate an octahedral ligand field. The chains are parallel in the crystal structure and interact via hydrogen bonds involving coordinated water molecules. However, the shortest metal–metal separation between two chains [5.3752 (3) Å] is large compared with the intrachain interactions. These structural features are compatible with a single‐chain magnet behaviour, as confirmed by preliminary magnetic studies.     

Oxidative splitting of secondary cycloalkanols by Pb(OAc)4-LiCl AND Pb(OAc)4-Cu(OAc)2 systems

Conclusions As the result of the reaction of cyclopentanol and cyclohexanol with the Pb(OAc)₄-LiCl and Pb(OAc)₄-Cu(OAc)₂ systems, -formylalkyl radicals CH₂(CH₂)_n+1CHO (n=2, 3) are formed, which are oxidized by these systems into -chloroalkanals and -alkenals, respectively.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1345–1348, June, 1984.     

卤素取代甲苯的合成及其在Co(OAc)2－Mn(OAc)2－NaBr催化下的液相氧化反应

合成了3-氟甲苯和另外5个氯或溴取代的3-氟甲苯,以Co(OAc)₂·4H₂O、Mn(OAc)₂·4H₂O和NaBr为催化剂用液相氧化反应将其氧化为相应的卤代苯甲酸。该反应产率较高,所得卤代苯甲酸纯度好。6个卤代的3-氟甲苯及6个相应的卤代苯甲酸其结构经IR、UV、¹H NMR、MS和元素分析所确证。     

双膦配合物Ru（OAc）_2（Ph_3P）（dppe）和Ru（OAc）_2（dppe）_2的设计合成、表征和氢化性能

Ｒｕ（ＯＡｃ）_２（Ｐｈ_３Ｐ）_２和１或２摩尔的双－（二苯基膦）乙烷（ｄｐｐｅ）在回流的甲苯中反应，分别生成双膦配位的Ｒｕ（ＯＡｃ）_２（Ｐｈ_３Ｐ）（ｄｐｐｅ）和Ｒｕ（ＯＡｃ）_２（ｄｐｐｅ）_２。并进行了元素分析、ＩＲ、ＮＭＲ等谱学表征。在温度－５０至４０℃的范围内，测定了Ｒｕ（ＯＡｃ）_２（Ｐｈ_３Ｐ）（ｄｐｐｅ）的￣（３１）Ｐ｛￣１Ｈ｝ＮＭＲ谱，讨论了配合物中膦配体的配位状态。在反应温度３０至９０℃、氢压１．０至５．０ＭＰａ的条件下，考察了两个配合物均相催化丙烯酸和苯乙烯的氢化性能。结果表明，题示的两个配合物是催化丙烯酸和苯乙烯氢化的有效催化剂。     

Direct carboxylation reaction of methane with CO by a Yb(OAc)3/Mn(OAc)2/NaClO/H2O catalytic system under very mild conditions

A new method of synthesis of acetic acid in water has been developed from the carboxylation of methane with carbon monoxide using lanthanide catalysts. Ytterbium(III) acetate has been found to be the most active catalyst among the compounds of the lanthanide series in the carboxylation reaction of methane with carbon monoxide. Sodium hypochlorite or hydrogen peroxide was used as the oxidant in this reaction. Sodium hypochlorite exhibited more favorable activity than hydrogen peroxide in the reaction. The catalytic activity was improved by the addition of transition-metal salts such as manganese(II) acetate. The best result has been found at a ratio of manganese(II) acetate to ytterbium(III) acetate of 1:10. The optimum reaction conditions (reaction temperature, 40 °C; time, 20 h; methane, 20 atm; carbon monoxide, 5 atm) have been obtained. © 1998 John Wiley & Sons, Ltd.     

Reaction of AgN3 with SOCl2: evidence for the formation of thionyl azide, SO(N3)2

Pure thionyl azide SO(N(3))(2), which is the only gaseous reaction product, has been generated in a vacuum by the heterogeneous reaction of SOCl(2) vapor with AgN(3) at room temperature at a SOCl(2) vapor pressure of 1 x 10(-3) Torr. Evidence for the formation of SO(N(3))(2) is given by on line photoelectron spectroscopy (PES) combined with outer valence Green's function (OVGF) calculations with the 6-311++G(2df) basis set. The good agreement between the PES experiment and the OVGF calculation shows that SO(N(3))(2) has C(1) symmetry. The first ionization energy of SO(N(3))(2) is 10.18 eV.     

An ab initio investigation of the electronic structure of lithium azide (LiN3), sodium azide (NaN3), and lead azide [Pb(N3)2]

Solid energetic substances have long played an important technological role as explosives, as well as for fuels. In this article, the authors concentrate on a type of explosive considered a primary explosive, lead azide, and its related compounds, lithium azide and sodium azide. Recent interest in more fundamental questions relating to the basic properties of these systems as materials, coupled with a desire to probe fundamental questions relating to the initiation and sustaining of the chemical reactions leading to combustion/detonation, is generating significant interest in the basic solid-state properties of such energetic systems. In particular, recent analysis of detonation by Gilman emphasizes the need to include excitation of the electronic system in obtaining an understanding. In this article, the band structures of the three solid metal azides are studied. This is done for both the normal lattice geometry and also in isotropically compressed geometries. These studies found that the alkali azide band gaps are far wider than is the lead azide gap and the lead azide gap is far more sensitive to narrowing with lattice compression than are the gaps for the alkali azides. In fact, the gap for sodium azide is found to widen with compression rather than narrow. The authors found that there is much seen in the band structures of these azides to lend some support to the Gilman model and also to demonstrate the importance of solid-state effects on the electronic structure and possible behavior of such energetic systems. © 1997 John Wiley & Sons, Inc.     

Oxidation of 3-carene with Pb(OAc)4 in benzene

Conclusions The products of the oxidation of 3-carene with lead tetraacetate in benzene contain, besides the previously identified compounds, also the acetates of trans-4-caren-3-ol, m-mentha-1,3-dien-8-ol and 2-(m-tolyl)-2-propanol, which serves to confirm the assumption that the given reaction proceeds in two directions: a) with the formation of the allylic organolead derivative; and b) of the adduct of 3-carene with Pb(OAc)₄, as intermediate products.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 45–49, January, 1973.