A new efficient and selective synthesis of ketones from alkanes or cycloalkanes, CO, and silanes in the presences of aprotic superacids

A new approach to the direct synthesis of ketones from alkanes or cycloalkanes (RH), CO, and silanes is proposed. Ketones were obtained in 50–97% yields from propane, butane, cyclopentane, cyclohexane, and methylcyclopentane on treatment with CO and silanes (Me₄Si, Et₄Si, orm- andp-XC₆H₄SiMe₃, where X=Cl, Me, OMe) in the presence of CX₄·2AlBr₃ (X=Br, Cl) superacids at 0°C. The reactions withm- andp-XC₆H₄SiMe₃ (X=Cl, Me) occur regioselectively to givem-ketones fromm-silanes andp-ketones fromp-silanes. However, the only product,p-MeOC₆H₄COR, is formed both fromm- andp-MeOC₆H₄SiMe₃. The reaction ofcyclo-C₅H₉CO⁺ with BzSiMe₃ results in an organosilicon ketone, Me₃SiCH₂C₆H₄COC₅H₉, while in the presence of an excess of an acylating system (after alcoholysis), Me₂Si(OR′)CH₂C₆H₄COR is formed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 947–952, May, 1998.     

Facile synthesis of (±)-2,6-dimethyloctan-1-ol formate,the biologically active analog of the smaller flour beetle aggregation pheromone,from 1-allyloxy- and 1-benzyloxy-2,6-dimethyl-2,7-octadienes,the telomers of isoprene with allyl and benzyl alcohols

A careful investigation of the telomerization of isoprene with allyl, benzyl, 2-chloroethyl and methyl alcohols on -allylpalladium complex catalysts was carried out. The structures of the obtained telomers were determined by¹H NMR spectroscopy. 1-Alkoxy-2,6-dimethyl-2,7-octadiene is a predominant telomer. 2,6-Dimethyloctan-1-ol, which reacts with HCOOH to give (±)-2,6-dimethyloctan-1-ol formate in high yield, was obtained from 1-allyloxy- and 1-benzyloxy-2,6-dimethyl-2,7-octadienes by the removal of allyl and benzyl protective groups and by the hydrogenation of double bonds.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1539–1543, August, 1995.     

Coordination chemistry of anticrowns: Complexation of cyclic trimeric perfluoro-o-phenylenemercury with nitro compounds

Cyclic trimeric perfluoro-o-phenylenemercury (o-C₆F₄Hg)₃ (1) is capable of reacting with nitromethane to give complex {[(o-C₆F₄Hg)₃](CH₃NO₂)} (2) containing one molecule of the nitro compound per one macrocycle molecule. In this complex, the nitromethane ligand is bound to 1 by its both oxygen atoms, one of which is simultaneously coordinated to all three Hg centres of the macrocycle while the other interacts with a single Hg centre. The complex of similar composition, {[(o-C₆F₄Hg)₃](C₆H₅NO₂)} (3), is produced in the interaction of 1 with nitrobenzene. In this complex too, the both oxygen atoms of the nitro group are involved in the bonding to the macrocycle. A distinctive feature of 3 is that here one oxygen atom of the coordinated nitro derivative is bound by only two Hg centres of 1 whereas the other interacts again with a single Hg site. The reaction of 1 with 5-nitroacenaphthene affords a 1:1 complex, {[(o-C₆F₄Hg)₃](C₁₂H₉NO₂)} (4), having a polydecker sandwich structure in the crystal. Unlike in 3, the aromatic rings of the nitroarene units in 4 are disposed virtually in parallel to the macrocycles. The nitro compound in 4 behaves again as a bidentate ligand, forming three Hg-O bonds with one of the adjacent macrocycles and a single Hg-O bond with another molecule of 1. The complex is characterized also by shortened Hg-C contacts between the Hg centres of 1 and the carbon atoms of the nitroarene moiety as well as shortened C-C contacts between the carbon atoms of the nitroarene and the macrocycle. In the interaction of 1 with 1-nitropyrene, complexes of two compositions, viz. {[(o-C₆F₄Hg)₃](C₁₆H₉NO₂)} (5) and {[(o-C₆F₄Hg)₃](C₁₆H₉NO₂)₃} (6) are formed. An X-ray diffraction study of 6 has shown that in this adduct two of three coordinated molecules of the nitro compound are located on one side of the metallacycle plane while the third nitroarene molecule is disposed on its other side. The aromatic rings of all three nitropyrene ligands in 6 are practically parallel to the mean plane of the macrocycle. In contrast to 2-4, each molecule of the nitroarene in 6 is bonded to 1 by a single oxygen atom which is coordinated only to one Hg centre. In the case of one of the nitropyrene ligands that forms much longer Hg-O bond with 1 than two others, an additional contribution to the bonding is made by shortened Hg-C contacts between the macrocycle and the carbon atoms of the aromatic pyrene core and also by shortened C-C contacts between the carbon atoms of the coordinated nitroarene and 1. The synthesized adducts are the first examples of complexes of an anticrown with nitro compounds.     

1,2,3,4,7-Pentamethylindenyl complex [(η5-C9H2Me5)RhI2]2 as a synthon for the [(η5-C9H2Me5)Rh]2+ fragment

The reaction of the iodide complex [(η⁵-C₉H₂Me₅)RhI₂]₂ (1) or the acetonitrile complex [(η⁵-C₉H₂Me₅)Rh(MeCN)₃]²⁺ with Tl[Tl(η-7,8-C₂B₉H₁₁)] afforded rhodacarborane (η⁵-C₉H₂Me₅)Rh(7,8-C₂B₉H₁₁) (2). The cationic triple-decker complex with the bridging boratabenzene ligand [Cp*Fe(μ-η:η-C₅H₃Me₂BMe)Rh(η⁵-C₉H₂Me₅)]²⁺ (3) was synthesized by the reaction of the nitromethane solvate [(η⁵-C₉H₂Me₅)Rh(MeNO₂)₃]²⁺ with the sandwich compound Cp*Fe(η-C₅H₃Me₂BMe). The structure of 2 was established by X-ray diffraction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1623–1625, August, 2008.     

Thermal arene exchange in the naphthalene complex [CpRu(η<Superscript>6</Superscript>-C<Subscript>10</Subscript>H<Subscript>8</Subscript>)]<Superscript>+</Superscript>

Naphthalene in the [CpRu(⁶−C₁₀H₈)]⁺ complex (1) is substituted for other arenes under reflux in 1,2-dichloroethane to form the [CpRu(⁶-arene)]⁺ cations (arene = C₆H₆, 1,2-C₆H₄Me₂, 1,2,4,5-C₆H₂Me₄, or C₆Me₆) in 70–80% yields. The reaction is accelerated in the presence of a catalytic amount of acetonitrile. The structure of [1]PF₆ was established by X-ray diffraction.     

Stereochemistry of chromium complexes with monosubstituted allenes

Previously unknown arenechromium dicarbonyl complexes with different allenes including functionally substituted ones were synthesized. The formed compounds represent a mixture of all three possible isomers and exhibit stereochemical nonrigidity. The isomerization process and stereochemical peculiarities of the complexes synthesized were studied using the ¹H NMR method.     

Synthesis and the fluxional behavior of the 30-electron cationic iron-molybdenum triple-decker complex with a central pentaphospholyl ligand, [(η-C7H7)Mo(μ-η:η-P5)Fe(η-C5Me5)]BF4

The reaction of [(η-C₇H₇)Mo(MeCN)₃)]BF₄ with (η-C₅Me₅)Fe(η-P₅) afforded the new 30-electron triple-decker complex [(η-C₇H₇)Mo(μ-η:η-P₅)Fe(η-C₅Me₅)]BF₄. Studies of the temperature dependence of the¹H NMR spectra demonstrated that the resulting compound contains a fluxional cyclohepatrienyl ligand. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1374–1376, July, 1999.     

Cationic arenerhodacarboranes [(ν-arene) Rh(ν-7,8-Me2-7,8-C2B9H9)]BF4

A new procedure was developed for the synthesis of (η³-C₈H₁₃)Rh(η-7,8-C₂B₉H₉) (1). This method involves the interaction of [codRhCl]₂ with Cs[7,8-Me₂-7,8-C₂B₉H₁₀] in CH₂Cl₂. The reactions of compound1 with arenes in trifluoroacetic acid afforded, the previously unknown cationic arenerhodacarboranes [(ν-arene) Rh(ν-7,8-Me₂-7,8-C₂B₉H₉)]BF₄ in high yields. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 592–594, March, 1999.     

η3-Propargyl complexes of molybdenum, tungsten, and rhenium

The reactions of the Me _n C₆H_6−n M(CO)₃ (M=Cr, Mo, W;n=3, 5, 6) and C₅R₅M(CO)₃ (M=Mn, Re; R=H, Me) complexes with propargyl alcohol in acidic media under UV irradiation were studied. Novel Me _n C₆H_6−n M(CO)₂(η³-C₃H₃)BF₄ (M=Mo, W;n=3, 5, 6) and C₅R₅Re(CO)₂(η³-C₃H₃)CF₃SO₃ complexes with the 3ē-propargyl ligand were synthesized, and their properties compared with those of similar η³-allyl derivatives. The structure and dynamic propeties of the compounds obtained are discussed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1796–1803, September, 1999.     

μ-Acyl Os3 clusters containing metallocenyl substituents and products of their protonation

Previously unknown μ-acyl osmium clusters containing simultaneously permethyl-metallocenyl and Os₃ cluster fragments were synthesized. The IR, UV, NMR (¹H and¹³C), and FAB-MS spectra were examined. Protonation of the clusters proceeds at the metal atom of the metallocenyl fragment. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 180–183, January, 1999.