The reaction of trichlorosilyltetracarbonyliron hydride (HFe(CO)4SiCl3) with conjugated dienes

Isoprene, 1,3-butadiene and 2,3-dimethyl-1,3-butadiene react with HFe(CO)₄SiCl₃ by addition of the Fe---H function to the diene. Isoprene appears to add predominantly 1,4 and 2,3-dimethyl-1,3-butadiene appears to add 1,2, while 1,3-butadiene may add both ways. In the case of isoprene and 1,3-butadiene loss of CO from the addition compound gives a stable π-allyl- Fe(Co)₃SiCl₃ product. Either cis- or trans-1,3-pentadiene is reduced to pentene by HFe(CO)₄SiCl₃.     

N‐(2‐Hydroxyethyl)‐N‐methyldithiocarbamato Complexes of Nickel(II) with Phosphorus Donor Ligands

Planar nickel(II) complexes involving N‐(2‐Hydroxyethyl)‐N‐methyldithiocarbamate, such as [NiX(nmedtc)(PPh₃)] (X = Cl, NCS; PPh₃ = triphenylphosphine), and [Ni(nmedtc)(P‐P)]ClO₄(P‐P = 1,1‐bis(diphenylphosphino)methane(dppm); 1,3‐bis(diphenylphosphino)propane (1,3‐dppp); 1,4‐bis(diphenylphosphino)butane(1,4‐dppb) have been synthesized. The complexes have been characterized by elemental analyses, IR and electronic spectroscopies. The increased νC–N value in all the complexes is due to the mesomeric drift of electrons from the dithiocarbamate ligands to the metal atom. Single crystal X‐ray structure of [Ni(nmedtc)(1,3‐dppp)]ClO₄·H₂O is reported. In the present 1,3‐dppp chelate, the P–Ni–P angle is higher than that found in 1,2‐bis(diphenylphosphino)ethane‐nickel chelates and lower than 1,4‐bis(diphenylphosphino)butane‐nickel chelates, as a result of presence of the flexible propyl back bone connecting the two phosphorus atoms of the complex.     

Novel generation of selenoaldehydes through stannic chloride-induced unsymmetrical C-Se bond cleavage of bis(N,N-dimethylcarbamoylseleno)methanes

Treatment of a benzene or a CH₂Cl₂ solution of bis(N,N-dimethylcarbamoylseleno)methanes with SnCl₄ afforded β-1,3,5-triselenanes, and the key intermediates, acylselonium ions and selenoaldehydes, were successfully trapped by using allyltrimethylsilane or 2,3-dimethyl-1,3-butadiene to obtain the allylation products or the cycloadducts, respectively.     

N-heterocyclic phosphenium cations: syntheses and cycloaddition reactions

A series of trifluoromethanesulfonate (OTf) salts of N-heterocyclic phospheniums (NHP) bearing phenyl (1a), para-methoxyphenyl (1b), 2,6-diisopropylphenyl (1c) and mesityl (1d) substituents is reported. The compounds are made by a modification to a literature procedure that improves the overall yields for and by 15 and 23%, respectively. Two unwanted side-products in the synthesis of , the diammonium salt, [(2,6-iPr-C6H3)N(H)2CH2CH2N(H)2(2,6-iPr-C6H3)]Cl2 (4) and the bisphosphine (2,6-iPr-C6H3)N(PCl2)CH2CH2N(PCl2)(2,6-iPr-C6H3) (5), are crystallographically characterized, as is the intermediate cyclic chlorophosphine, C1PN(4-OMe-C6H4)CH2CH2N(4-OMe-C6H4) (3b). The phenyl-substituted NHP is fully characterized, including by X-ray crystallography, for the first time; this compound contains a short P-O contact of 2.1850(14) A. Cycloaddition reactions of with 2,3-dimethyl-1,3-butadiene give the expected spirocyclic phospholeniums, 7,8-dimethyl-1,4-diaryl-1,4-diaza-5-phopshoniaspiro[4.4]non-7-ene, as their OTf salts (6a-d), while reactions with N,N'-dimesityl-1,4-diaza-1,3-butadiene give, except in the case of , which is too bulky to react, the aza analogues, 1,4-dimesityl-6,9-diaryl-1,4,6,9-tetraaza-5-phosphoniaspiro[4.4]non-2-ene (7a, 7b and 7d). The sterically congested is in thermal equilibrium with and free diazadiene, and undergoes a substitution reaction with 2,3-dimethyl-1,3-butadiene to give .     

An ion crystal based on MnII-Schiff-base and Keggin polyanions

A new polyoxometalate-templated manganese-Schiff-base compound 1, {[Mn(L)₂]₂[PMo₁₂O₄₀][Cl] · DMF · 2CH₃CN · CH₃OH} _n (where L is 1,4-bis(4-imidazolyl)-2,3-diaza-1,3-butadiene, DMF is N,N-dimethylformamide) has been synthesized by introducing the Metal-Schiff-base into polyoxometalates(POMs) at room temperature, and structurally characterized by elemental analysis, infrared spectroscopy, and single-crystal X-ray diffraction analysis. The result of the single crystal X-ray diffraction suggested that the compound has the packing of the Mn(II)-Schiff-base cation layer and Keggin anion layer.     

Catalytic and regioselective synthesis of gem‐ or trans‐α,β‐unsaturated amides by carbonylation of alkyl alkynes with aniline derivatives by palladium(II) and phosphine

The reaction of carbonylative addition of alkyl alkynes to aniline derivatives has been successfully achieved by a catalytic system formed of Pd(OAc)₂ and a suitable bidentate phosphine ligand. The reaction led mainly to gem‐α,β‐unsaturated amides ( 3 ) with Pd(OAc)₂/1,3‐bis(diphenylphosphino)propane/p‐toluenesulfonic acid/CO as the catalytic system. However, the reaction catalyzed by Pd(OAc)₂/1,4‐bis(diphenylphosphino)butane/H₂/CO in CH₂Cl₂ as a solvent affords trans‐α,β‐unsaturated amides ( 4 ) as the major product. Copyright © 2003 John Wiley & Sons, Ltd.     

rac-[CH2(3-tert-butyl-1-indenyl)2]ZrCl2/MAO in the Copolymerization of Olefins and Dienes

Olefin-diene copolymerizations in the presence of C₂ symmetric zirconocene rac-[CH₂(3-tert-butyl-1-indenyl)₂]ZrCl₂/MAO catalytic system have been reported and rationalized by experimental and molecular modeling studies. Ethene gives 1,2-cyclopropane and 1,2-cyclopentane, 1,3-cyclobutane, and 1,3-cyclopentane units in copolymerization with 1,3-butadiene, 1,4-pentadiene, and 1,5-hexadiene, respectively. Propene-1,3-butadiene copolymerizations lead to 1,2 and 1,4 butadiene units and to a low amount of 1,2-cyclopropane units.     

Cationic polymerization of dimethyl-1,3-butadienes

The cationic polymerizations of dimethyl-1,3-butadienes with various catalysts in methylene chloride and toluene have been investigated. The activity of catalysts decreased in the order WCl₆ > AcClO₄ > SnCl₄·TCA > BF₃OEt₂. The homopolymerization rate of dimethyl-1,3-butadienes with WCl₆, AcClO₄, and SnCl₄·TCA decreased in the order 1,3-dimethyl-1,3-butadiene > 2,3-dimethyl-1,3-butadiene > 1,2-dimethyl-1,3-butadiene > 2,4-hexadiene. The polymers prepared with WCl₆, SnCl₄.TCA, and BF₃OEt₂ were rubberlike polymers or white powders, whereas those prepared with AcClO₄ were oily oligomers. The 1,4-propagation increased in the order 1,2-dimethyl-1,3-butadiene < 1,3-dimethyl-1,3-butadiene < 2,3-dimethyl-1,3-butadiene < 2,4-hexadiene. This order may indicate that the steric effect of methyl group determine primarily the microstructure of the polymer. The relative reactivity of dimethyl-1,3-butadienes toward a styryl cation decreased in the order 1,3-dimethyl-1,3-butadiene > 1,2-dimethyl-1,3-butadiene > 2,3-dimethyl-1,3-butadiene > 2,4-hexadiene. This order may be explained in terms of the stability of the resulting allylic cation.     

Diphenylphosphinoderivate von Malein- und Fumarsäureestern: Darstellung,Eigenschaften, Kristall- und Molekülstrukturen

The reaction between 2,3-dichloromaleic acid dialkylester (alkyl=CH₃ and C₂H₅) and diphenyl(trimethylsilyl)phosphine, leading to diphenylphosphine substituted esters of maleic and fumaric acid has been studied. With a molar ratio 1:1 of the components 2-chloro-3-diphenylphosphinomaleic acid dimethylester (3) and-diethylester are obtained as colourless crystalline compounds. From a 1:2 reaction however only bis(diphenylphosphino)fumaric acid dimethylester (colourless crystals) and-diethylester (yellow) can be crystallized, the latter in a partially oxydized form. The presence of bis(diphenylphosphino)maleic acid diester in the oily part of the reaction products has been proved by its chelating with Ni²⁺ and Pd²⁺ to complexes of the compositionMeCl₂·(PP). Pure bis(diphenylphosphino)maleic acid dimethylester (4) could be synthesized by alcoholysis and following methylation of bis (diphenylphosphino)maleic anhydrid. Contrary to this easily chelating and air stable compound the corresponding fumaric acid diesters give no complexes with the metals examined as far and are very sensitive towards oxygen. This sensitivity decreases strongly after oxydation to 2-diphenylphosphino-3-diphenylphosphorylfumaric acid diester, the diethylester of which could be crystallized in pure form.Characteristic vibration bands, uv/vis-absorption and³¹P-nmr peaks are discussed.The result of X-ray diffraction data of3 and4 are reported and conformation, bond lengthes and bond angles of these molecules are given.     

Concerted coordination and hydrogen‐bonding network of the 1,4‐di‐4‐pyrid­yl‐2,3‐diaza‐1,3‐butadiene [Zn(MeOH)2(H2O)2](ClO4)2 3:1 complex

In the title compound, diaqua­bis(1,4‐di‐4‐pyrid­yl‐2,3‐diaza‐1,3‐butadiene)dimethanolzinc(II) bis­(perchlorate) 1,4‐di‐4‐pyrid­yl‐2,3‐diaza‐1,3‐butadiene methanol 1.72‐solvate 1.28‐hydrate, [Zn(C₁₂H₁₀N₄)₂(CH₄O)₂(H₂O)₂](ClO₄)₂·C₁₂H₁₀N₄·1.72CH₄O·1.28H₂O, determined at ca 110 K, the Zn cation and the extended dipyridyl ligand both lie across inversion centres in space group P. The structure consists of a network arrangement of the constituent species stabilized by a combination of coordination, hydrogen bonding and π–π forces. Uncoordinated methanol and water solvent mol­ecules occupy the otherwise void spaces within and between the networks.     

Bis(diphenylphosphino)amid-komplexe des platins,palladiums und nickels. Kristallstruktur des N-methylierungsprodukts {CH3N[(C6H5)2P]2}2Pd2+ 2SO3F−

Reaction of lithiated bis(diphenylphosphino)amine, [(C₆H₅)₂P]₂N^? Li⁺, with K₂PtCl₄ or PdCl₂ (in the presence of trimethylphosphine) yields the homoleptic bis[bis(diphenylphosphino)amide] complexes I and II, respectively. With NiCl₂/(CH₃)₃P the chloro-bridged dinuclear complex III is obtained. A symmetrical bonding of the Ph₂P-·N-·PPh₂ anion to the metal through the phosphorus atoms is indicated for these diamagnetic, deep-yellow (I, II) or red (III) complexes by ³¹P NMR spectroscopy (J(PtP) 1812 Hz for I). I and II are dissolved in CF₃COOH with protonation at the nitrogen atoms to give bis(diphenylphosphino)amine complexes IV and V, respectively (J(PtP) 2080 Hz for IV). IV and V are 1:2 electrolytes in CH₃NO₂. Methylation of I-III with CH₃OSO₂F leads to the bis(diphenylphos-phino)methylamine complexes VI-VIII, of which the palladium compound VII has been structurally characterized by single crystal X-ray diffraction. VII contains a planar CNP₂PdP₂NC skeleton and is thus based on planar ligand arrays both at Pd and at the two N atoms.     

Study of 1,3‐Dipolar Cycloaddition and Ring Contraction of New 1,4‐Phenylene‐bis[1,5]benzothiazepine Derivatives

Some 1,4‐phenylene‐bis[1,2,4]oxadiazolo‐[5,4‐d][1,5]benzothiazepine derivatives ( 4a , 4b , 4c ) were synthesized by 1,3‐dipolar cycloaddition reaction of benzohydroximinoyl chloride with 1,4‐phenylene‐bis(4‐aryl)‐2,3‐dihydro[1,5]benzothiazepine ( 2a , 2b , 2c ); meanwhile, compounds 2a , 2b , 2c also occurred ring contraction under acylating condition to obtain bis[2‐aryl‐2′‐(β‐1,4‐phenylenevinyl)‐3‐acetyl]‐2,3‐dihydro[1,5]benzothiazoles ( 3a , 3b , 3c ). The structures of some novel compounds were confirmed by IR, ¹H‐NMR, elemental, and X‐ray crystallographic analysis.     

Rhodium‐Catalyzed 1,4‐Addition of Lithium 2‐Furyltriolborates to Unsaturated Ketones and Esters for Enantioselective Synthesis of γ‐Oxo‐Carboxylic Acids By Oxidation of the Furyl Ring with Ozone

Rhodium‐catalyzed 1,4‐addition of lithium 5‐methyl‐2‐furyltriolborate ([ArB(OCH₂)₃CCH₃]Li, Ar=5‐methyl‐2‐furyl) to unsaturated ketones to give β‐furyl ketones was followed by ozonolysis of the furyl ring for enantioselective synthesis of γ‐oxo‐carboxylic acids. [Rh(nbd)₂]BF₄ (nbd=2,5‐norbornadiene) chelated with 2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl (binap) or 2,3‐bis(diphenylphosphino)butane (chiraphos) gave high yields and high selectivities in a range of 91–99 % ee at 30 °C in a basic dioxane/water solution. The corresponding reaction of unsaturated esters, such as methyl crotonate, had strong resistance under analogous conditions, but the 1,4‐adduct was obtained in 70 % yield and with 94 % ee when more electron‐deficient phenyl crotonate was used as the substrate.     

Pd(0)‐catalyzed polyaddition of bifunctional vinyloxiranes with 1,3‐dicarbonyl compounds: The synthesis of polymers containing hydroxy and carbonyl groups

The palladium(0)‐catalyzed polyaddition of bifunctional vinyloxiranes [1,4‐bis(2‐vinylepoxyethyl)benzene ( 1a ) and 1,4‐bis(1‐methyl‐2‐vinylepoxyethyl)benzene ( 1b )] with 1,3‐dicarbonyl compounds [methyl acetoacetate ( 4 ), dimethyl malonate ( 6 ), and Meldrum's acid ( 8 )] was investigated under various conditions. The polyaddition of 1 with 4 was carried out in tetrahydrofuran with phosphine ligands such as PPh₃ and 1,2‐bis(diphenylphosphino)ethane (dppe). Polymers having hydroxy, ketone, and ester groups in the side groups ( 5 ) were obtained in good yields despite the kinds of ligands employed. The number‐average molecular weight value of 5b was higher than that of 5a . The polyaddition of 1b and 6 was affected by the kinds of ligands employed. The corresponding polymer 7b was not obtained when PPh₃ and 1,2‐bis(diphenylphosphino)ferrocene were used. The polyaddition was carried out with dppe as the ligand and gave polymer 7b in a good yield. The molecular weight of the polymer obtained from 1b and 8 was much higher than those of polymers 5b and 7b . The polyaddition with Pd₂(dba)₃ · CHCl₃/dppe as a catalyst (where dba is dibenzylideneacetone) produced polymer 9b in a 92% yield (number‐average molecular weight = 45,600). The stereochemistries of all the obtained polymers were confirmed as an E configuration by the coupling constant of the vinyl proton. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2487–2494, 2002     

Reactions of Stable α‐Chlorosulfanyl Chlorides with CS‐Functionalized Compounds

The smooth reaction of 3‐chloro‐3‐(chlorosulfanyl)‐2,2,4,4‐tetramethylcyclobutanone ( 3 ) with 3,4,5‐trisubstituted 2,3‐dihydro‐1H‐imidazole‐2‐thiones 8 and 2‐thiouracil ( 10 ) in CH₂Cl₂/Et₃N at room temperature yielded the corresponding disulfanes 9 and 11 (Scheme 2), respectively, via a nucleophilic substitution of Cl^? of the sulfanyl chloride by the S‐atom of the heterocyclic thione. The analogous reaction of 3‐cyclohexyl‐2,3‐dihydro‐4,5‐diphenyl‐1H‐imidazole‐2‐thione ( 8b ) and 10 with the chlorodisulfanyl derivative 16 led to the corresponding trisulfanes 17 and 18 (Scheme 4), respectively. On the other hand, the reaction of 3 and 4,4‐dimethyl‐2‐phenyl‐1,3‐thiazole‐5(4H)‐thione ( 12 ) in CH₂Cl₂ gave only 4,4‐dimethyl‐2‐phenyl‐1,3‐thiazol‐5(4H)‐one ( 13 ) and the trithioorthoester derivative 14 , a bis‐disulfane, in low yield (Scheme 3). At ?78°, only bis(1‐chloro‐2,2,4,4‐tetramethyl‐3‐oxocyclobutyl)polysulfanes 15 were formed. Even at ?78°, a 1 : 2 mixture of 12 and 16 in CH₂Cl₂ reacted to give 13 and the symmetrical pentasulfane 19 in good yield (Scheme 5). The structures of 11, 14, 17 , and 18 have been established by X‐ray crystallography.     

Bis(alkoxycarbonyl) complexes of platinum: preparation,reactivity and their role in carbonylation reactions

bis(alkoxycarbonyl) complexes of platinum of the type [Pt(COOR)₂L] [L = 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), l,4-bis(diphenylphosphino)butane (dppb), 1,1'-bis(diphenylphosphino)ferrocene (dppf) or 1,2-bis-(diphenylphosphino)benzene (dpb); R = CH₃, C₆H₅ or C₂H₅] were obtained by reaction of [PtCl₂L] with carbon monoxide and alkoxides. Palladium and nickel complexes gave only carbonyl complexes of the type [M(CO)L] or [M(CO)₂L]. The new complexes were characterized by chemical and spectroscopic means. The X-ray structure of [Pt(COOCH₃)₂(dppf] · CH₃OH is also reported. The reactivity of some alkoxycarbonyl complexes was also investigated.     

A new supramolecular compound based on Mn(II)-Schiff-base and Keggin-type [PMo12O40]3−

A new organometallic-inorganic hybrid compound {[Mn(L)₂]₂[PMo₁₂O₄₀][NO₃] · 4CH₃OH · 3H₂O} _n (I), where L is 1,4-bis(4-imidazolyl)-2,3-diaza-1,3-butadiene) was synthesized in situ from [PMo₁₂O₄₀]^3?, Mn²⁺ and L reaction in an H₂O-DMSO-CH₃OH mixture at room temperature, and the product was structurally characterized by elemental analysis, infrared spectroscopy, and single-crystal X-ray diffraction analysis. Compound I is constructed from alternating layers of the metal-Schiff-base cation and Keggin anions based on electrostatic forces and hydrogen bond interactions.     

Cumulative subject index: Vol. 126(1977)–150(1978)

1,3-Cyclooctadiene reacts with trimethylaluminum and potassium according to the equation 4K + 4Al(CH₃)₃ + 2C₈H₁₂

3K[Al(CH₃)₄]+K[(C₈H₁₂)₂Al] to give potassium bis(3,8-cis-cyclooctenyl) aluminate. The compound can be described as a bicyclo derivative of cyclooctene formed by the 1,4 addition to 1,3-cyclooctadiene. The structure of the complex was determined from 4500 unique data measured by single crystal X-ray diffractometer techniques. Full matrix least squares refinement gave final agreement factors of R₁ = 0.043 (observed data) and R₂ = 0.045 (all data) in the monoclinic space group P2₁/c (a = 9.658(6), b = 12.220(8) and c = 14.150(9)Å; β = 113.85(1)°; V = 1527.43 Å; Z = 4 for ?_calc = 1.23 g cm^?3).     

Investigations of olefin hydrogenation catalysts. The major species present in solutions containing rhodium(I) complexes of chelating diphosphines

¹H and ³¹P NMR spectroscopy are used to determine the nature of the species present in catalytically active solutions prepared by treating [RhCl(C₂H₄)₂]₂ with diphosphines and [Rh(norbornadiene)diphosphine]BF₄ with hydrogen (diphosphine = 1,3-bis(diphenylphosphino)propane (dppp) and isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane (diop)).     

Asymmetric Hydroformylation of 4‐Vinyl‐1,3‐dioxolan‐2‐one

A chiral cyclic carbonate, 4‐vinyl‐1,3‐dioxolan‐2‐one was used as racemic substrate in asymmetric hydroformylation. The catalysts were formed in situ from “pre‐formed” PtCl₂(diphosphine) and tin(II) chloride. (2S,4S )‐2,4‐Bis(diphenylphosphinopentane ((S,S )‐BDPP)), (S,S )‐2,3‐O‐izopropylidine‐2,3‐dihydroxy‐1,4‐bis(diphenylphosphino)butane ((S,S )‐DIOP)), and (R )‐2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl ((R )‐BINAP)) were used as optically active diphosphine ligands. The platinum‐containing catalytic systems provided surprisingly high activity. The hydroformylation selectivities of up to 97% were accompanied by perfect regioselectivity towards the dioxolane‐based linear aldehyde. The enantiomeric composition of all components in the reaction mixture was determined and followed throughout the reaction. The unreacted 4‐vinyl‐1,3‐dioxolan‐2‐one was recovered in optically active form. The kinetic resolution was rationalized using the enantiomeric composition of the substrate and the products.