Alkylsilver(I) induced 1,5-substitution in functionally conjugated enynes. a novel route to cumulated trienes

Functionally conjugated enynes, H₂CC(R¹)CCCR²R₃OS(O)Me, undergo 1,5-substitution with alkylsilver(I) reagents, RAGG ☆ 3 LiBr. The purity of the produced alkylated butatrienes, RCH₂C(R¹)CCCR²R³ depends on the nature of R in RAg ☆ 3 LiBr and on the substituents R¹, R² and R³ in the substrate.     

The preparation of 1-hydroperfluorohexyne,octyne and decyne

1-hydroperfluoroalkynes (R_FCCH, R_F  C₄F₉, C₆F₁₃, C₈F₁₇) were prepared from the corresponding alkenes by a multistep process involving bromination, dehydrobromination and debromination reactions. The influence of the perfluorinated chain's length on chemical reactivity is illustrated by the important changes in experimental procedure, with respect to the lower terms, needed for the bromination and debromination steps. Physical data are reported for compounds R_FCBr₂CH₂Br, R_FCBrCHBr and R_FCCH.     

Reactions of tetralouroethene oligomers Part 6. Some reactions of 4-diazo-1,1,1,2,2-pentaflouro-3-pentaflouethyl-3-triflouromethylbutane

The isocyanate R_fCH₂NCO (R_f=CF₃(C₂F₅)₂C)reacts under strongly acidic conditions to form the salt R_fCH₂NH₃⁽⁺⁾HSO₄⁽⁻⁾(1) which yields, on treatment with sodium nitrite the diazaoalkane R_fCHN₂ (3). Dissolution of (1) in D.M.S.O. gives, by a remarkable decomposition reaction, the alkane R_fH (2). Reaction of (3) with excess sodium nitrite affords the isocyanate R_fNCO (4) which is stable to water,but which reacts with ammia to give the urea R_fNHCONH₂ (5); this latter was not readily hydrolysed .Photolysis of (3) yields the diazadiene R_fCHNNCH R_f (7). Thermolysis of (3) alone afforded the diazadiene (7), but reaction in the presence of copper (II) perchlorate afforded (7) and the aldehyde R_fCHO (6)     

Some diels—alder reactions of η1-bonded cyclopentadienylmetal compounds

Bis(cyclopentadienyl)mercury readily undergoes Diels—Alder reactions with RCCR (R = CO₂Me or CF₃), CF₃CFCFCF₃, CF₃CFCF₂, (CF₃)₂CC(CN)₂, C₂(CN)₄ and Ph$\text{NCONNC}$O to give stable adducts characterised by¹H, ¹⁹F and ¹³C NMR, spectroscopy. Similar reactions of CF₃CCCF₃ and CF₃CFCFCF₃ with the cyclopentadiene derivatives Me₃MC₅H₅ and (Me₃M)₂C₅H₄ (M = Si, Sn) are also described.     

Reactivite d'alcynes fluores vis-a-vis de methylthiolates [(η5-C5H5)M(SMe)(CO)3] et d'hydrures [(η5-C5H5)MH(CO)3] de molybdene et de tungstene

The electron deficient acetylene, hexafluorobut-2-yne, reacts with molybdenum and tungsten methanethiolate derivatives (prepared in situ) to give vinyl and three-, five-, or six-membered heterocyclic derivatives: [Cp(OC)- $\text{MoC(O)C(CF}{}_3\text{)C(CF}{}_3\text{)C(O)S}$Me], [Cp(OC)₂$\text{MC(CF}{}_3\text{)C(CF}{}_3\text{)C(CF}{}_3\text{)C(O)S}$Me], [CpW(CO)₃C(CF₃C(CF₃)SMe], [CpW{η³-$\text{C(CF}{}_3\text{)C(CF}{}_3\text{)C(SMe)OC}$(O)}-(CO)₂]. These reactions contrast with those of trifluoropropyne where no organometallic species are obtained. On heating or irradiation with CF₃CCCF₃ [CpMH(CO)₃] gives known bridged species and in the presence of dimethyl disulphide the vinyl derivative [CpM(CO)₃C(CF₃)C(CF₃)H]and an isomer of undetermined structure.     

Reactivity of olefin an acetylene complexes of platinum(0) towards tetrachloro-o-benzoquinone

Tetracloro-o-benzoquinone reacts with (diphenylacetylene)bis(tirphenylphosphine)platinum(0) to give the novel platinum(II) diphenylacetylene complex, Pt(C₆Cl₄O₂)PhCCPh)(PPh₃), (I), which reacts with hydrogen halides to give the compelexes cis-PtX₂(PhCCPh((PPh₃), (X = Cl or Br). Hydrogen chloride also readily removes the tetrachloro-o-benzoquinoneligand from the adducts Ni(C₆Cl₄O₂)(Ph₂PCH₂CH₂PPh₂) and M(C₆Cl₄O₂)(PPh₃)₂, (M = Pd or Pt) but it has no reaction upon Ir(Cl)(C₆Cl₄O₂)(CO)(PPh₃)₂ at room temperature. The acetylene in (1) is susceptible to nucleophilic attact and reaction with diethylamine gives the vinyl adduct Pt(C₆Cl₄O₂)(CPhCPh)NHEt₂)(PPh₃). Other reactions of (I) have also been studied. Attemps to prepare other olefin or acetylene complexes of platinum(II) by the action of tetrachlor-o-benzoquinone on the complexes Pt(L)(PPh₃)₂, (L = PhCCH,(Et)(Me)(HO)CCCC(OH)(Me)(Et), HOCH₂OH, CF₃CCCF₃, CF₂CF₂, CF₂CH₂ or trans-PhCHCHPh) are also described.     

Preparation of η2-acetylene- and η1-vinylidene-manganese complexes from p-diethynylbenzene and cymantrene. X-ray crystal and molecular structure of Cp(OC)2MnCCHC6H4CBrCH2

Cp(OC)₂Mn(THF) reacts with p-diethynylbenzene (Deb), yielding Cp(OC)₂Mn(Deb) (I) and [Cp(OC)₂Mn]₂(Deb) (II) with the η²-acetylene coordination of Deb (to both Mn atoms in II). Under the action of PhLi, I and II are isomerized into Cp(OC)₂MnCCHC₆H₄CCH (III) and [Cp(OC)₂MnCCH]₂C₆H₄ (VI). Treatment of I with PhLi, LiBr and an excess of HCl in ether, as well as direct interaction of III with LiBr and HCl/Et₂O, gives Cp(OC)₂MnCCHC₆H₄CBrCH₂ (IV), which has been characterized by an X-ray single-crystal diffraction study. III adds PPh₃, yielding a zwitterionic complex, Cp(OC)₂Mn⁻C(P⁺Ph₃)CHC₆H₄CCH (V).     

Übergangsmetall—carbin-komplexe : II. trans-halogeno-diäthylaminocarbin-tetracarbonyl-komplexe des wolframs aus äthoxydiathylaminocarbenpentacarbonyl-wolfram(0)

A crystal structure analysis shows that hexafluoro-2-butyne reacts with bis(acetylacetonato)palladium(II) to give Pd[OC(Me)CH(COMe)C(CF₃)C(CF₃₎]₂ in which the hexafluoro-2-butyne links the γ-CH of the β-diketonato ligands to the palladium. Other palladium(II)β-diketonato systems behave similarly.     

Thiocyanatomercuration des acetyleniques. Synthese de derives β-(iso)thiocyanatoalcenyl mercuriques,d'α-halo β-thiocyanato alcenes et de thiocyanato-1 alcynes-1

In the presence of (SCN)^? mercuric chloride HgCl₂ adds to acetylenic compounds R¹CCR² affording in most cases α-chloromercuri-β-thiocyanatoalkenes R¹C(SCN)C(R²)HgCl and if R¹ = R² = Et or n-Bu isothiocyanates R¹C(NCS)C(R²)HgCl. The action of halogens or thio compounds affords α-halo-β-thiocyanatoalkenes. Most of the reported reactions are regio- and stereo-specific, in particular both RC(SCN)CHBr and RCBrCHSCN may be regiospecifically obtained from 1-alkynes RCCH. The synthesis of 1-thiocyanato-1-alkynes is also reported.     

The reaction of 3,3-dichloroallyltrimethylsilane with n-butyllithium

n-Butyllithium reacts with 3,3-dichloroallyltrimethylsilane to metalate the vinyl proton. Under the reaction conditions the Me₃SiCH₂C(Li)CCl₂ formed undergoes β-elimination of LiCl to give ClCCCH₂SiMe₃ whose subsequent reaction with n-butyllithium produces LiCCCH₂SiMe₃. Addition of trimethylchlorosilane gives Me₃SiCCCH₂SiMe₃. When two molar equivalents of n-butyllithium are used, further metalation of LiCCCH₂SiMe₃ gives LiCCCH(Li)SiMe₃. The action of N-bromosuccinimide on Me₃SiCH₂CHCCl₂ resulted in formation of Me₃SiCHCHCCl₂Br.     

gem-Difluoroallyllithium: Preparation by the transmetalation procedure and some reactions

3,3-Difluoroallyltrimethyltin has been prepared by the reaction of β-trimethylstannylethylidenetriphenylphosphorane with chlorodifluoromethane. This tin compound reacts with n-butyllithium in tetrahydrofuran at -95°C to generate gem-difluoroallyllithium. The latter, however, is not stable in solution at that temperature. If generated in situ in the presence of a triorganochlorosilane, products of the type R₃SiCF₂CHCH₂ are obtained in good yield. Addition to the CO bond of 3-pentanone to give (C₂H₅)₂C(OH)CF₂CHCH₂ was achieved by the method of alternate, incremental additions.     

Reactions of alkynes with bis(triphenylphosphine)platinum-ethylene: A 31P-{1H} NMR study

Internally consistent assignments of the ³¹P-{¹H} NMR parameters of the complexes [Pt(RCCR′)(PPh₃)₂] are proposed, based on the premise that the magnitude of ¹J(PtP) depends mainly on the nature of the moiety CR trans to P. For a given R, ²J(PP) correlates with ¹J(PtP) for thebond trans to CR. The alkynes PhCCSnEt₃, PhCCSnPh₃, Me₃SiCCCl, Me₃SiCCBr, Et₃SiCCI and MeCCI undergo oxidative addition reactions with [Pt(C₂H₄)(PPh₃)₂]; the intermediate alkyne complex was detected for PhCCSnEt₃, Me₃SiCCCl and Me₃CCBr. The triyne Me(CC)₃Me forms platinum(0) complexes by coordination with the central or terminal CC bond and appears also to give a platinum(II) complex by oxidative addition.     

Silylation as a protective method for terminal alkynes in organometallic synthesis : Preparation of 1,4-diethynyltetrafluorobenzene and (pentafluorophenyl)acetylene

Hexafluorobenzene reacts with Et₃SiCCLi to give p- Et₃SiCCC₆F₄CCSi-Et₃ and pentafluorophenylcopper couples with BrCCSiEt₃ to give C₆F₅CCSiEt₃ in good yield. Treatment of the products with aqueous methanolic alkali gives p-HCCC₆F₄CCH and C₆F₅CCH respectively.     

On the reaction of metallated acetylenes and allenes with carbon disulfide. Influence of the alkali metal counter-ion and the substituents in the acetylene and allene on the course of the reaction

Addition at low temperatures of carbon disulfide to a solution of the lithium compound

(R¹ = CH₃, C₃H₇, Ph, OCH₃, SCH₃) results in the initial formation of an allenic carbodithioate H₂CCC(R¹)CSSLi, while for R¹ = t-C₄H₉ or SiMe₃ acetylenic carbodithioates R¹CCCH₂CSSLi are formed. The initial products undergo very rapid subsequent reactions. For R¹ = CH₃ or C₃H₇ the lithium compound adds (in the allenic form) in a conjugated fashion to the CCCS system of the allenic carbodithioate. The acetylenic dithioates are deprotonated to give the geminal dithiolates R¹CCCHC(SLi)₂. For R¹ = Ph, OCH₃ or SCH₃, subsequent deprotonation at the terminal carbon atom of the initial allenic dithioate gives enyne dithiolates HCCC(R¹)C(SCH₃)₂; this reaction proceeds more satisfactorily with the potassium compounds.     

Novel sulfur-nitrogen-fluorine compounds : synthesis and properties of SF5NHF,SF5NClF and SF4NF

Using reactions developed for the synthesis of CF₂NF, CF₃NClF and CF₃NHF from ClCN, F₃SN can now be converted in high yield to the analogous sulfur compounds, SF₄NF, SF₅NClF and SF₅NHF. N-fluorotetrafluorosulfurimine is the simplest sulfur(VI) imine and is a rigid molecule. Details on the synthesis and properties of these novel compounds will be presented.     

The reaction of perfluoro-2,4-dialkyloxolanes with anhydrous aluminum chloride

Several kinds of perfluoro-2,4-dialkyloxolanes (A), having such alkyl groups as R_fR′_fCF₃ (2a); R_fC₂F₅, R′_fCF₃ (3a); R_fCF₃, R′_fC₂F₅ (4a); R_fR′_fC₂F₅ (5a); R_fCF₃, R′_fnC₃F₇ (6a) on the 2 and 4 positions of the oxolane ring, respectively, were treated with AlCl₃ in a heterogeneous reaction to give the corresponding perfluoro-2,5,5-trichloro-2,4-dialkyloxolanes (B). For purposes of comparison, the respective reactions of perfluoro-2-methyl-oxolane (la), perfluoro-2-n-butyloxolane (7a), and perfluoro-2, 5-dimethyloxolane (8a) with AlCl₃ were also conducted. An increasingly higher reaction temperature was needed for the reaction of A with AlCl₃ to give B as the carbon number of A increased. Cis- and trans-perfluoro-4-chloro-2,4-dimethyl-γ-butyrolactones (2c) were obtained from the hydrolytic reactions of cis- and trans-perfluoro-2,5,5-trichloro-2,4-dimethyloxolanes (2b), respectively, with fuming H₂SO₄. Physical properties and ¹⁹F nmr data are given for these new compounds.     

Syntheses of σ-cyclobut-1-en-3-onyl complexes by cycloaddition of ketenes to some transition metal alkynyl complexes

Reactions of ketenes (R¹R²CCO) with (η⁵-C₅H₅)Ni(PPh₃)CCR (I) and (η⁵-C₅H₅)Fe(CO)(L)CCR (III, L = CO and PPh₃) give σ-cyclobut-1-en-3-onyl complexes, {(η⁵-C₅H₅)Ni(PPh₃)$\text{CC(R)COC}$}R¹R² (VI) and (η⁵-C₅H₅)Fe(CO)(L)$\text{CC(R)COC}$R¹R² (IX)}, (2 + 2) cycloaddition products, in good yields. The σ-cyclobutenonyl complexes also can be prepared by the reaction of I and III with acyl chlorides in the presence of triethylamine.     

1-Alkoxy-2-azaallenyl-komplexe von chrom und wolfram

The successive reaction of (CO)₆M with Na[NCR₂¹] and [Et₃O]BF₄ yields (CO)₅M[C(NCR₂¹)OEt] (II: M = Cr; III: M = W; CR₂¹ = C(C₆H₄Br-p)₂ (a), CPh₂ (b), C(C₆H₄OMe-p)₂ (c), C(C₆H₄)₂O (d), CBu₂^tt (e)). Hexacarbonyltungsten, (CO)₆W, reacts with Na[NCPh₂] and MeOSO₂F to give (CO)₅W[C(NCPh₂) OMe] (IV). X-Ray analysis of IIe shows that: (1) the CNC fragment is almost linear (171.7°); (2) the two NC bond lengths are equal within experimental error; and (3) the O,C,Cr,N plane is perpendicular to the C(Me₃),C,N,C(Me₃) plane (90.0°). Therefore compounds II–IV are best described as 1-alkoxy-2-azaallenyl complexes.     

The syntheses and mass spectra of P[CCCF3]3, As[CCCF3]3, and Sb[CCCF3]3

The syntheses of P[CCCF₃]₃, As[CC CF₃]₃, and Sb[CCCF₃]₃ are reported. The compounds are colorless and volatile, with melting points of ?20° to ?25°, 23–24°, and 55–56°C, respectively. The mass spectra show the molecular ion of each compound. The rearrangement ion [F₃CCCCCCF₂]⁺] gives the strongest peak in each spectrum.     

On the reactions of dimethylsulfoxide with acyl fluorides - pummerer rearrangements and formation of monofluoromethyl esters

In stoichiometry-dependent reactions, dimethylsulfoxide (DMSO) reacts with acyl fluorides, R_fC(O)F (R_f = F, CF₃), to yield CH₃SCH₂F and R_fC(O)OCH₂F, while CH₃SCH₂Cl and FC(O)OCH₂Cl are obtained with COClF. Oxalyl difluoride, C₂O₂F₂, reacts with DMSO to give CH₃SCH₂F and FCH₂OCH₂F.