Action d'organozinciques α-ethyleniques sur le chloroformiate d'ethyle: preparation d'esters β-ethyleniques

The reaction of organozinc compounds RCHCHCH₂ZnBr with ethyl chloroformate gives β-ethylenic esters CH₂CHCH(R)COOC₂H₅ in good yields; these esters are readily converted to the corresponding α-ethylenic esters on treatment with piperidine.     

Insertion of N-sulfinylsulfonamides and bis(methylsulfonyl)sulfur diimide into ironcarbon σ bonds

The N-sulfinylsulfonamides R′S(O)₂NSO (R′ = CH₃, p-CH₃C₆H₄) insert into the FeR bonds of η⁵-C₅H₅Fe(CO)₂R (R = CH₃, CH₂C₆H₅) to afford η⁵-C₅H₅Fe(CO)₂N[S(O)₂R′][S(O)R]. These products undergo oxidation by m-ClC₆H₄C(O)-OOH to η⁵-C₅H₅Fe(CO)₂N[S(O)₂R′][S(O)₂R] and rearrange on storage to η⁵-C₅H₅Fe(CO)₂S(O)[NS(O)₂R′]R. Reaction between the η⁵-C₅H₅Fe(CO)₂R and CH₃S(O)₂NSNS(O)₂CH₃ leads to the insertion products η⁵-C₅H₅Fe(CO)₂N-[S(O)₂CH₃][S(R)NS(O)₂CH₃].     

Structure cristalline et configuration relative d'un complexe du titanocene presentant une chiralite plane et une chiralite centree sur l'atome de titane

The crystalline structure of the racemic form m.p. 164° C of the compound (h⁵ -3-MeC₅H₃C(Me₂)C₆H₅)(h⁵-C₅H₅)Ti (2,6-Me₂C₆H₃O)Cl has been determined by X-ray diffraction to establish the relative configuration of the two chiral moieties. This compound may be used further as a reference for studies on dynamic stereochemistry around the titanium atom. A systematic absolute nomenclature is proposed for this type of structure.     

Reactions of π-benzeneruthenium(II) complexes with alkylating reagents

The compounds (π-C₆H₆)Ru(R)Cl(PPh₃) (RCH₃, C₆H₅), (π-C₆H₆)RuCl(π-C₃H₅) and [(π-C₆H₆)Ru(π-C₅H₅)]Cl are described. The ³¹P NMR spectra of a series of tertiary phosphine complexes of the π-benzeneruthenium system are also reported.     

Reactions of coordinated propargyl and allene ligands in cyclopentadienyliron dicarbonyl complexes

Reactions of η⁵-C₅H₅Fe(CO)₂CH₂CCR (R  CH₃, C₆H₅, and CH₂Fe(CO)₂(η⁵-C₅H₅)) with HBF₄ in acetic anhydride yield [η⁵-C₅H₅Fe(CO)₂(η²CH₂CCHR)]⁺BF^?₄. The resultant cationic iron-η²-allene complexes react with a wide range of nucleophiles (Nu) to give the following types of behavior: (a) addition of Nu to carbon-1 of the η²-allene fragment (with NaBH₄, (C₂H₅)₂NH, and P(C₆H₅)₃, inter alia), (b) addition of Nu to carbon-2 of the η²-allene fragment (with NaOCH₃), (c) addition of Nu to the carbonyl carbon (with NaOC₂H₅), (d) deprotonation of the iron-η²-allene cation to the parent propargylic complex (with N(C₂H₅)₃), and (e) nonselective reactions to yield a mixture of products (with CH₃Li). Of these, the most common is behavior (a); together with the protonation of η⁵-C₅H₅Fe(CO)₂CH₂CCR it stimulates the two-step (3 + 2) cycloaddition reactions between electrophilic molecules and these iron-propargyl complexes.     

Extension de la reaction de Wittig: Condensation “d'ylures enolates” sur les cetones aliphatiques

The enolate ylide Ph₃P⁺C^?C(Ph)O^?Li₊ obtained by the reaction of HMPT-Li with the benzoylmethylenetriphenylphosphorane Ph₃PCHCOPh reacts with aliphatic ketones, in contrast to its precursor. This condensation makes it possible to prepare β,γ-unsaturated ketones, of type RCHC(R′)CH₂COPh, instead of the α,β isomer usually obtained in a Wittig reaction.     

Reactions of pentafluorosulfanyliminodihalosulfanes,SF5NSX2, with nucleophiles. Preparation and characterization of pentafluorosulfanylsulfinylamine,SF5NSO.

Reactions of SF₅NSF₂ with sodium alkoxides and aryloxides have produced both the mono- and disubstituted derivatives SF₅NS(F)OR and SF₅NS(OR)₂, where RCH₃, CH₂CHCH₂, C₆H₅, p-C₆H₄NO₂, p-C₆H₄Br, p-C₆H₄CN. The reaction of SF₅NSCl₂ with AgNCO produced SF₅NS(NCO)₂. This diisocyanate can also be prepared from the reaction of SF₅NSCl₂ with KOCN in liquid SO₂. The proposed intermediate, SF₅NSO, in the hydrolysis of SF₅NSF₂ was prepared from the low temperature reaction of SF₅NSCl₂ and Ag₂O in C₆H₅NO₂. The new pentafluorosulfanyl derivatives were characterized by IR, ¹H and ¹⁹F NMR, mass spectrometry and where possible ¹³C NMR and elemental analysis.     

Photochemistry of methyl- and n1-benzyl-n5-cyclopentadienyltricarbonyltungstein(II)

Irradiation of solutions of n⁵-C₅H₅W(CO)₃R (R  CH₃n1-CH₂C₆H₅) in cyclohexane at ca. 310490 nm leads to the formation of [n⁵-C₅H₅W(CO)₃]₂ and methane and of n⁵-C₅H₅W₅(CO)₂(n³-CH₂C₆H₅) and some [n⁵-C₅H₅W(CO)₃]₂, respectively. When the irradiation is carried out in the presence of excess P(C₆H₅)₃, the photoproducts are n⁵-C₅H₅W(CO)₂[P(C₆H₅)₃]CH₃ (R  CH₃) and n⁵-C₅H₅W(CO)₂(n₃-CH₂C₆H₅) and trace [n⁵-C₅H₅W(CO)₃]₂ (R  n¹-CH₂C₆H₅). Photolysis of the n⁵-C₅H₅W(CO)₃R in the presence of benzyl chloride affords n⁵-C₅H₅W(CO)₃Cl (R  CH₃) and both n⁵-C₅H₅W(CO)₂(n³-CH₂C₂H₅) and n⁵-C₅H₅W(CO)₃Cl (R  n¹-CH₂C₆H₅), the relative amounts of the latter products depending on the quantity of added C₆H₅CH₂Cl. Irradiation of n⁵-C₅H₅W(CO)₃-CH₃ in the presence of both P(C₆h₅)₃ and C₆H₅CH₂Cl affords n⁵-C₅H₅W(CO)₂-[P(C₆H₅)₃]CH₃, but no n⁵-C₅H₅W(CO)₃Cl. It is proposed that the primary photo-reaction in these transformations is dissociation of a CO group from n⁵-C₅H₅W-(CO)₃R to generate n⁵-C₅H₅W(CO)₂R, which can either combine with L to form a stable 18 electron complex, n⁵-C₅H₅W(CO)₂(L)R (L  CO, P(C₅H₅)₃; LR  n³-CH₂C₆H₅), or lose the group R in a competing, apparently slower step. This proposal receives support from the observation that, light intensifies being equal, n⁵-C₅H₅W(CO)₃CH₃ undergoes a considerably faster photoconversion to [n⁵-C₅H₅W(CO)₃]₂ under argon than under carbon monoxide.     

Exploratory organometal-sulfur chemistry; syntheses and unusual properties of rhenium CH2SR,CHSRR′, and CHSR]+ complexes

The methylidene complex [(η-C₅H₅)Re(NO)(PPh₃)(CH₂)]⁺PF₆^?(I) yields kinetically labile sulfonium salts when treated with CH₃SCH₃, CH₃SCH₂C₆H₅, and (η-C₅H₅)Re(NO)(PPh₃)(CH₂SCH₃) (V);the binuclear adduct formed in the latter case, [(η-C₅H₅)Re(NO)(PPh₃)CH₂]₂S⁺CH₃ (VI), is substantially more stable than the others and undergoes hydride transfer disproportionation to [(η-C₅H₅)Re(NO)(PPh₃)(CHSCH₃)]⁺PF₆^?(VII) and (η-C₅H₅)Re(NO)(PPh₃)(CH₃) (VIII) when heated.     

Photochemical studies on η5-cyclopentadienyl(triphenylphosphine)nickelalkyl and -aryl compounds

Photo-induced degradation studies of a series of organonickel complexes of the type (η⁵-C₅H₅)(PPh₃)Ni(R) (R = CH₃, C₂H₅, C₆H₅ and C₆H₄CH₃-p) as well as certain deuterated analogs have been undertaken. Photolysis of the methyl compounds in benzene as well as benzene-d₆ gives methane as the major gaseous product, the photogenerated methyl group abstracting hydrogen from either the cyclopentadienyl ring, from the solvent, or from another methyl group. The photo-induced dealkylation of the ethyl compound gives both ethylene and ethane, and is explained by β-hydride elimination followed by subsequent reaction of the hydrido intermediate with additional ethyl compound. The photolysis of the phenyl and p-tolyl complexes in benzene solution leads to biaryl formation, both from the coupling of two coordinated aryl groups as well as interactions with the solvent. Triphenylphosphine is a product in all of these photo-decomposition studies.     

Vinyliden-Übergangsmetallkomplexe: II. Die Protonierung der Vinyliden-Komplexe C5H5Rh(CCHR)(PPri3) und ihre stufenweise Umwandlung in Vinyl- und α-Halogenalkyl-Rhodiumverbindungen

The protonation ofC₅H₅Rh(CCH₂)(PPrⁱ₃) (I) by CF₃CO₂H, HCl and HI gives the vinylrhodium compounds C₅H₅Rh(CHCH₂)(PPrⁱ₃)X (II-IV). The reaction of III (X = Cl) and IV (X = I) with a second molecule of HCl leads to the formation of the α-chloroethyl complexes C₅H₅Rh(CHClCH₃)(PPrⁱ₃)X (VII, VIII). The stereochemistry of these products allows us to propose a mechanism for HCl addition to the CC double bond of the vinyl ligand. C₅H₅Rh(CCHPh)(PPrⁱ₃) (XII) reacts with CF₃CO₂H and HI to give the kinetically preferred compounds C₅H₅Rh(Z-CHCHPh)(PPrⁱ₃)X (XIVa, XVa) of which XIVa (X = CF₃CO₂) in4bpolar solvents rearranges smoothly to form the thermodynamically more stable E isomer C₅H₅Rh(E-CHCHPh)(PPrⁱ₃)OCOCF₃ (XIVb). C₅H₅Rh(E-CHCHPh)(PPrⁱ₃)I (XVb) is obtained from XIVb and NaI. The protonation reactions of C₅H₅Rh(CCHMe)(PPrⁱ₃) (XIII) with CF₃CO₂H, HCl and HI always produce mixtures of isomers of the complexes C₅H₅Rh(CHCHMe)(PPrⁱ₃)X (XVI-XVIII). The ratio of Z to E isomers (≈ 62/38) is not dependent on the anion X and is also not influenced by the polarity of the solvent.     

Die thermische reaktion von C5H5(CO)2FeNa mit benzimidchloriden C6H5(Cl)CNR

η⁵-C₅H₅(CO)₂FeNa reacts with the benzimide chlorides C₆H₅(Cl)CNR (R  CH(CH₃)₂, C₆H₅) in boiling THF to give the η¹-iminoacyl complexes η⁵-C₅H₅ (CO)₂Fe[η¹-C(C₆H₅)NR]. Alternatively, the new Fe complexes [η⁵-C₅H₅(CO)Fe$\text{C(C}{}_6\text{H}{}_5\text{)N(CH}{}_3\text{)C(C}{}_6\text{H}{}_5\text{)N}$CH₃PF₆ (IV) and [η⁵-C₅H₅(CO)₂FeC(C₆H₅)N(CH₃)C(C₆H₅)NCH₃]PF₆ (V) are formed under the same conditions, if R  CH₃. Hudrolysis of the CN single bond of the ligand in V, not stabilized by a chelate effects as in IV, results in the formation of [η⁵-C₅H₅(CO)₂FeC(C₆H₅)NHCH₃]PF₆ (VII). Reaction of η⁵-C₅H₅(CO)₂ with N-benyzylbenzimido chloride yields η⁵-C₅H₅(CO)₂FeCH₂C₆H₅ as the only isolated product.     

Utilisation en synthese du cation iminium genere in situ par oxydation electrochimique d'amines tertiaires

The electrochemical oxidation in acetonitrile of aliphatic amines (ACH₃) in presence of a non-nucleophilic base (2,4,6-collidine) and of compounds containing weakly-activated hydrogens (RH) such as diethyl phosphonate and diethyl malonate gives the substituted derivatives ACH₂R. These compounds result from the addition of the anion R^? to the iminium cation ACH₂⁺. Such a reaction is obtained with tribenzylamine and N,N-dimethyl-p-toluidine. Moreover (CH₃)₂NCH₂-CH(CO₂C₂H₅)₂ is deaminated and gives by successive Michael reactions other substituted malonates which also react with the iminium cation (CH₃)2N⁺CH₂.     

π-cyclopentadienyls of nickel(II) : XV. Insertion reaction of RNCS into the nickel—carbon bond

η⁵-C₅H₅NiPBu₃CH(CN)₂ (I) readily undergoes ethyl- or phenyl-isothiocyanate insertion, producing the stable products η⁵-C₅H₅NiPBu₃SC(NRH) = C(CN)₂ (IIIa; R = C₂H₅, IIIb; R = C₆H₅. η⁵-C₅H₅NiPPh₃CH(CN)₂ (II) reacts with RNCS (R = C₂H₅ and C₆H₅) to undergo two types of insertion reaction; with C₂H₅NCS, η⁵C₅H₅NiPPh₃SC[N(C₂H₅)H] = C(CN)₂ (IVa) is obtained, with C₆H₅NCS, on the other hand, η⁵-C₅H₅NiPPh₃SC(NC₆H₅)CH(CN)₂ (IVb) is produced. p ]IIIa and IIIb react with PBu₃ to give ionic complexes [η⁵-C₅H₅Ni(PBu₃)₂]⁺ [SC(NC₂H₅H)C(CN)₂]^? (Va) and [η⁵-C₅H₅Ni(PBu₃)₂]⁺ [SC(NC₆H₅)CH(CN)₂]^?(Vb), respectively.     

Cleavage of iron2-alkenyl and iron2-alkynyl bonds by mercury(II) chloride

Reactions of HgCl₂ with η⁵-C₅H₅Fe(CO)₂R (R  CH₂CHCH₂ and CH₂C(CH₃)CH₂) in THF at 25°C rapidly afford $\text{1}\text{1}$ adducts of the two reactants. These adducts were converted to the corresponding PF₆^? salts, [η⁵-C₅H₅Fe(CO)₂(η²-CH₂C(R)CH₂HgCl)]⁺ PF₆^? (R  H and CH₃), for characterization. Slower reactions with cleavage of the ironcarbon σ bond and elimination of the R group from η⁵-C₅H₅Fe(CO)₂R occur for R  CH₂CHC(CH₃)₂, CH₂CHCHC₆H₅, and CH₂CCC₆H₅. Both elimination and $\text{1}\text{1}$ adduct formation are observed when R  CH₂CHCHCH₃. The kinetics of the cleavage reactions are presented and possible mechanisms for both cleavage and $\text{1}\text{1}$ adduct formation are discussed.     

Vinylidene transition-metal complexes: I. Novel rhodium(I) and rhodium(III) complexes containing alkynes,alkynyls, and vinylidenes as ligands.Crystal structure of IC5H5Rh(CCHPh)(PPri3)

The syntheses of the novel cyclopentadienylphosphinevinylidenerhodium complexes C₅H₅Rh(CCHR)(PPrⁱ₃) (R = Ph, Me, H) and, for R = Ph, of the isomeric alkynyl hydrido compound C₅H₅ RhH(C₂Ph)(PPrⁱ₃) are reported. The square-planar complexes trans-[RhCl(RC₂H)(PPrⁱ₃)₂] (IIa, IIb), which in solution are in equi-librium with the five-coordinated pyridine to give the octahedral compounds RhHCl(C₂R)(PRrⁱ₃)₂(py) (VIa, VIb). Treatment of Via, VIb with NaC₅H₅ gives the vinylidene complexes IVa, IVb in good yield. C₅H₅Rh(CCH₂)(PPrⁱ₃) (IVc) is directly obtained from trans-[RhCl(C₂H₂)(PPrⁱ₃)₂] (IIc) and NaC₅H₅. Mechanistic studies confirm that the reaction of VIa, VIb with the cyclopentadienide anion primarily gives, by elimination of HCl, the rhodium(I) compounds trans-[Rh(C₂R)(py)(PPrⁱ₃)₂] (VIIIa, VIIIb), which react with cyclopentadiene, possibly via trans-[Rh(C₂R)(η²-C₅H₆)(PPrⁱ₃)₂](X) as an intermediate, to give C₅ VIIIa with cyclopentadiene in presence of water gives the complex C₅H₅RhH(C₂Ph)(PPrⁱ₃), which isomerizes only slowly to form IVa and, therefore, is not an intermediate in the reaction of VIIIa and C₅H₆ to give IVa. The crystal structure of IVa has been determined. The RhCC arrangement is almost linear. The RhC distance is significantly shorter than in carbenerhodium complexes, which, in agreement with ¹³C NMR data and MO calculations, indicates a high degree of multiple bonding.     

Self-recognition by the iron chiral auxiliary [(η5-C5H5)Fe(CO)(PPh3] in the formation of (RR,SS)-[(η5-C5H5)FE(CO)(PPh3)COCH2]2CH2

Complete self-recognition of chirality is observed in the Michael addition of the enolate derived from R,S-[η⁵-C₅H₅Fe(CO)(PPh₃-COCH₃] to the acryloyl complex R,S-[(η⁵-C₅H₅Fe(CO)(PPh₃)-COCHCH₂)] to generate exclusively the single diastereoisomer of the glutaroyl complex RR,SS-[(η⁵-C₅H₅)Fe(CO)(PPh₃)COCH₂]₂CH₂.     

Zur Kenntnis von Tribenzylzinn- und Tribenzyltitancyclopentadienyl

About Tribenzyltin- and Tribenzyltitaniumcyclopentadienyl The organocerium(III) compound Na(THF)[(π-C₅H₅)₃Ce(σ-C₅H₅)] ( I ) reacts with (C₆H₅CH₂)₃SnCl and (C₆H₅CH₂)₃TiCl after a S_N-reaction under separation of Nacl and (C₅H₅)₃Ce to tribenzyltin- resp.-titaniumcyclopentadienyl (C₆H₅CH₂)₃MC₅H₅ [M = Sn, ( II ); Ti, ( III )]. A special characterization of II and III was carried out by their elementary analysis, I.R. spectroscopy and ¹H, ¹³C, and ¹¹⁹Sn N.M.R. spectroscopy. These results allow the statement that II and III are better to be described by the formulae (C₆H₅CH₂)₃Sn(σ-C₅H₅) and (C₆H₅CH₂)₃Ti(π-C₅H₅), respectively.     

Synthese nouvelle d'allylcetones par voie organosilicique

In the presence of a Lewis acid (AlCl₃, InCl₃, GaCl₃), acyl chlorides react with allyltrimethylsilane to give the corresponding allyl ketones, CH₂CHCH₂COR, in good yields.Substituted allylsilanes, synthesized by 1,4-disilylation of conjugated dienes, give a similar reaction. The electrophilic substitution of SiMe₃ by a COR group occurs with allylic rearrangement and therefore silylated β,γ-ethylenic ketones,

, are obtained. In most cases the allylic ketones prepared isomerize easily to the corresponding conjugated ketones; ketones having the formula CH₂CHCH₂COR lead uniquely to the trans-,propenylketones, MeCHCHCOR.     

Ionization and appearance potentials in organic chemistry. I—energetic aspects of the mass spectra of stereoisomeric 4-substituted N-alkyl-2-methyldecahydroquinol-4-ols

The ionization potentials for the stereoisomers of trans-fused 1,2-dimethyl- and 1-ethyl-2-methyl-4-R-decahydroquinol-4-ols (R?C?CH, CH?CH₂ or C₂H₅) and the appearance potentials for the [M–CH₃]⁺ and [M–C₂H₅]⁺ ions (loss of 2-CH₃ and 4-C₂H₅ groups potential, respectively) were measured by using the electron impact method. The ionization and appearance potential for [M–CH₃]⁺ are always lower for the isomers with the axial 2-CH₃ group. For the C-2 epimers, the difference between the appearance potentials for the [M–CH₃]⁺ ion values is likely to be equal to the enthalpy differences between the ground states of the epimers and the dissociation energy differences between the axial and equatorial C₂–CH₃ bonds. The appearance potentials for [M–C₂H₅]⁺ for the C-4 epimers possessing the 4-C₂H₅ group were very similar. At the same time, the appearance potentials for the [M–CH₃]⁺ ions were lower for less stable epimers which had an axial 4-C₂H₅ group.