2519-10-0Relevant articles and documents
A ruthenium racemisation catalyst for the synthesis of primary amines from secondary amines
Pingen, Dennis,Altinta?, ?i?dem,Rudolf Schaller, Max,Vogt, Dieter
supporting information, p. 11765 - 11771 (2016/07/28)
A Ru-based half sandwich complex used in amine and alcohol racemization reactions was found to be active in the splitting of secondary amines to primary amines using NH3. Conversions up to 80% along with very high selectivities were achieved. However, after about 80% conversion the catalyst lost activity. Similar to Shvo's catalyst, the complex might deactivate under the influence of ammonia. It was revealed that not NH3 but mainly the primary amine is responsible for the deactivation.
Synthesis of multisubstituted cyclopentadienes from cyclopentenones prepared via catalytic double aldol condensation and nazarov reaction sequence
Nishina, Yuta,Tatsuzaki, Tomohiro,Tsubakihara, Ayano,Kuninobu, Yoichiro,Takai, Kazuhiko
, p. 2585 - 2589 (2011/11/29)
The rhenium-catalyzed synthesis of cyclopentenone derivatives via double aldol condensation and successive Nazarov reaction is described. The cyclopentenones were converted to the corresponding cyclopentadienes using organolithium reagents. Cyclopentadien
Hydrogenation and dehydrogenation of pentaphenylcyclopentadienes and pentaphenylcyclopentenes
Kanthak, Matthias,Muth, Enrico,Dyker, Gerald
experimental part, p. 6084 - 6091 (2011/03/17)
Pentaaryl-substituted cyclopentadienes and cyclopentenes have been employed in catalytic hydrogenation and photochemical cyclodehydrogenation reactions, targeting strained bowl-shaped structures. Both types of reactions generally stop at the monohydrogena
Fused supracyclopentadienyl ligand precursors. synthesis, structure, and some reactions of 1,3-diphenylcyclopenta[l]phenanthrene-2-one, 1,2,3-Triphenylcyclopenta[l]phenanthrene-2-ol, 1-Chloro-1,2,3-triphenylcyclopenta[l]phenanthrene, 1-Bromo-1,2,3-triphenylcyclopenta[l]phenanthrene, and 1,2,3-Triphenyl-1H-cyclopenta[l]phenanthrene
Dennis, Glen D.,Edwards-Davis, David,Field, Leslie D.,Masters, Anthony F.,Maschmeyer, Thomas,Ward, Antony J.,Buys, Irmi E.,Turner, Peter
, p. 135 - 146 (2008/02/02)
The photochemical reaction of 1,3-diphenylcyclopenta[l]phenanthrene-2-one 5 (phencyclone) with oxygen in acetone leads to the formation of 1,2,3-trihydro-1,2,3-triphenylcyclo-penta[l]phenanthrene 7 (9,10-dibenzoylphenanthrene) along with a trace of the lactone 1,4-diphenylcyclo-3-pyran[l]phenanthrene-2-one 8. An independent synthesis of 8 was achieved by the reaction of 5 with FeCl3 in CHCl3. The treatment of 5 with phenyllithium yields 1,2,3-triphenylcyclopenta[l]phenanthrene-2-ol 9-OH in good yield. Subsequent reaction of 9-OH with SOCl2 or SOBr2 in pyridine leads to the formation of the halo-analogues 1-chloro-1,2,3-triphenylcyclopenta[l]phenanthrene 9-Cl and 1-bromo-1,2,3-triphenylcyclopenta[l]phenanthrene 9-Br, respectively. Treatment of 9-OH with HBr in acetic acid affords the rearranged product 1,1,3-triphenylcyclopenta[l]phenanthrene-2-one 10 with a trace of 9-Br. Treatment of 9-Cl or 9-Br with zinc in acetic acid affords 1,2,3-tri-phenyl-1H-cyclopenta[l]phenanthrene 9-H. 9,10-Phenanthrenediylbis(phenyl)methanone 7 is formed in good yield upon treatment of 9-OH with HI in acetic acid followed by heating with H 2PO4. Compounds 7, 8, 9-Cl, 9-Br, and 10 have been structurally characterized using X-ray crystallography. CSIRO 2006.
Combined ruthenium(II) and lipase catalysis for efficient dynamic kinetic resolution of secondary alcohols. Insight into the racemization mechanism
Martin-Matute, Belen,Edin, Michaela,Bogar, Krisztian,Kaynak, F. Betuel,Baeckvall, Jan-E.
, p. 8817 - 8825 (2007/10/03)
Pentaphenylcyclopentadienyl ruthenium complexes (3) are excellent catalysts for the racemization of secondary alcohols at ambient temperature. The combination of this process with enzymatic resolution of the alcohols results in a highly efficient synthesis of enantiomerically pure acetates at room temperature with short reaction times for most substrates. This new reaction was applied to a wide range of functionalized alcohols including heteroaromatic alcohols, and for many of the latter, enantiopure acetates were efficiently prepared for the first time via dynamic kinetic resolution (DKR). Different substituted cyclopentadienyl ruthenium complexes were prepared and studied as catalysts for racemization of alcohols. Pentaaryl-substituted cyclopentadienyl complexes were found to be highly efficient catalysts for the racemization. Substitution of one of the aryl groups by an alkyl group considerably slows down the racemization process. A study of the racemization of (S)-1-phenylethanol catalyzed by ruthenium hydride η5-Ph5CpRu(CO) 2H (8) indicates that the racemization takes place within the coordination sphere of the ruthenium catalyst. This conclusion was supported by the lack of ketone exchange in the racemization of (S)-1-phenylethanol performed in the presence of p-tolyl methyl ketone (1 equiv), which gave 1% of 1-(p-tolyl)ethanol. The structures of ruthenium chloride and iodide complexes 3a and 3c and of ruthenium hydride complex 8 were confirmed by X-ray analysis.
Use of polymeric reaction product
-
, (2008/06/13)
A reaction product (A) which can be prepared by reaction, under free radical conditions, of at least one monomer (a) capable of free radical reaction, in the presence of at least one free radical initiator and of a radical of the formula (III) where R1 to R3, in each case independently of one another, are hydrogen, methyl or a radical-stabilizing and/or bulky group selected from an unsubstituted or substituted, linear or branched alkyl of two or more carbon atoms, cycloalkyl, alcohol, ether, polyether, amine, aralkyl radical, a substituted or unsubstituted aromatic, heterocyclic or olefinic hydrocarbon, a halogen atom, a substituted or unsubstituted, linear or branched alkenyl or alkynyl group, —C(O)R5, —C(O)OR5, —CR5R6—O—R7, —O—C(O)R5, —CN, —O—CN, —S—CN, —O—C═NR5, —S—C═NR5, —O—CR5R6—CR7R8NR9R10, —N═C═O, —C═NR5, —CR5R6-Hal, —C(S)R5, —CR5R6—P(O)R7R8, —CR5R6—PR7R8, —CR5R6—NR7R8, —CR5R6(OR7)(OR8), —CR5R6(OR7)(NR8), —CR5R6(NR7)(NR8), an anhydride, acetal or ketal group, —SO2R5, an amidine group, —NR5C(S)NR6, —NR5C(S)—OR6, —N═C═S, —NO2, —C═N—OH, —N(R5)═NR6, —PR5R6R7, —OSiR5R6R7 or —SiR5R6R7, where R5 to R10, independently of one another in each case, are defined in the same way as R1 to R5, or two of the radicals R1 to R4 form a C4- to C7-ring which in turn may be substituted or unsubstituted and, if required, may contain one or more heteroatoms, with the proviso that at least two of the radicals R1 to R3 are a radical-stabilizing and/or bulky group as defined above, has various uses.
Lewis acid mediated reactions of zirconacyclopentadienes with aldehydes: One-pot synthetic route to indene and cyclopentadiene derivatives from aldehydes and benzyne or alkynes
Zhao, Changjia,Li, Pixu,Cao, Xiaoyu,Xi, Zhenfeng
, p. 4292 - 4298 (2007/10/03)
One-pot procedures for the preparation of highly substituted indenes, tetrahydroindenes, and cyclopentadienes have been developed by using a combination of zirconocene-mediated C-C-bond-forming reactions with Lewis acid mediated activation of carbonyl groups. The carbonyl groups of aldehydes were deoxygenated in the reaction and behaved formally as a one-carbon unit. A variety of Lewis acids were checked and showed different reactivities in this reaction.
Palladium-catalyzed arylation of cyclopentadienes
Dyker, Gerald,Heiermann, Joerg,Miura, Masahiro,Inoh, Jun-Ichi,Pivsa-Art, Sommai,Satoh, Tetsuya,Nomura, Masakatsu
, p. 3426 - 3433 (2007/10/03)
Cyclopentadiene and metallocenes, typically zirconocene dichloride, are suitable substrates for multiple arylations with aryl bromides in palladium-catalyzed reactions. Thus, various aryl bromides bearing either an electron-donating or an electron-withdrawing substituent can react with these substrates to afford the corresponding 1,2,3,4,5-pentaaryl-1,3-cyclopentadienes in a single preparative step. Derivatives of cyclopentadiene, including di- and trisubstituted cyclopentadienes, and indene are arylated in a similar fashion.
Deoxygenative cycloaddition of aldehydes with alkynes mediated by AlCl3 and zirconium: Formation of cyclopentadiene derivatives
Xi, Zhenfeng,Li, Pixu
, p. 2950 - 2952 (2007/10/03)
Cleavage of the aldehyde C=O bond takes place in the zirconocene- and AlCl3-mediated cyclization of two molecules of an alkyne with an aldehyde to afford cyclopentadiene derivatives [Eq. (1)]. Only one of the possible double-bonds isomers is fo
Palladium-catalysed reaction of aryl bromides with metallocenes to produce pentaarylated cyclopentadienes
Miura, Masahiro,Pivsa-Art, Sommai,Dyker, Gerald,Heiermann, Joerg,Satoh, Tetsuya,Nomura, Masakatsu
, p. 1889 - 1890 (2007/10/03)
Aryl bromides can efficiently react with some metallocenes, typically zirconocene dichloride, in the presence of a palladium/phosphine catalyst system and an appropriate base to produce the corresponding pentaarylated cyclopentadienes.
