Transient Silenes as Versatile Synthons – The Reaction of Dichloromethyl‐tris(trimethylsilyl)silane with Organolithium Reagents

Treatment of dichloromethyl‐tris(trimethylsilyl)silane (Me₃Si)₃Si–CHCl₂ ( 1 ), prepared by the reaction of tris(trimethylsilyl)silane with chloroform in presence of potassium tertbutoxide, with organolithium reagents (molar ratio 1 : 3) affords the bis(trimethylsilyl)methyl‐disilanes Me₃SiSiR₂–CH(SiMe₃)₂ ( 12 a–d ) ( a : R = Me, b : R = n‐Bu, c : R = Ph, d : R = Mes). The formation of 12 a–d is discussed as proceeding through an exceptional series of isomerization and addition reactions involving intermediate silyl substituted carbenoids and transient silenes. The carbenoid (Me₃Si)₂PhSi–C(SiMe₃)LiCl ( 8 c ) is moderately stable at low temperature and was trapped with water to give (Me₃Si)₂PhSi–CH(SiMe₃)Cl ( 9 c ) and with chlorotrimethylsilane affording (Me₃Si)₂PhSi–CCl(SiMe₃)₂ ( 7 c ). For 12 d an X‐ray crystal structure analysis was performed, which characterizes the compound as a highly congested silane with bond parameters significantly deviating from standard values.     

Silicon‐ and Tin‐Containing Open‐Chain and Eight‐Membered‐Ring Compounds as Bicentric Lewis Acids toward Anions

Herein, we report the syntheses of silicon‐ and tin‐containing open‐chain and eight‐membered‐ring compounds Me₂Si(CH₂SnMe₂X)₂ ( 2 , X=Me; 3 , X=Cl; 4 , X=F), CH₂(SnMe₂CH₂I)₂ ( 7 ), CH₂(SnMe₂CH₂Cl)₂ ( 8 ), cyclo‐Me₂Sn(CH₂SnMe₂CH₂)₂SiMe₂ ( 6 ), cyclo‐(Me₂SnCH₂)₄ ( 9 ), cyclo‐Me_(2?n)X_nSn(CH₂SiMe₂CH₂)₂SnX_nMe_(2?n) ( 5 , n=0; 10 , n = 1, X= Cl; 11 , n=1, X= F; 12 , n=2, X= Cl), and the chloride and fluoride complexes NEt₄[cyclo‐ Me(Cl)Sn(CH₂SiMe₂CH₂)₂Sn(Cl)Me?F] ( 13 ), PPh₄[cyclo‐Me(Cl)Sn(CH₂SiMe₂CH₂)₂Sn(Cl)Me?Cl] ( 14 ), NEt₄[cyclo‐Me(F)Sn(CH₂SiMe₂CH₂)₂Sn(F)Me?F] ( 15 ), [NEt₄]₂[cyclo‐Cl₂Sn(CH₂SiMe₂CH₂)₂SnCl₂?2 Cl] ( 16 ), M[Me₂Si(CH₂Sn(Cl)Me₂)₂?Cl] ( 17 a , M=PPh₄; 17 b , M=NEt₄), NEt₄[Me₂Si(CH₂Sn(Cl)Me₂)₂?F] ( 18 ), NEt₄[Me₂Si(CH₂Sn(F)Me₂)₂?F] ( 19 ), and PPh₄[Me₂Si(CH₂Sn(Cl)Me₂)₂?Br] ( 20 ). The compounds were characterised by electrospray mass‐spectrometric, IR and ¹H, ¹³C, ¹⁹F, ²⁹Si, and ¹¹⁹Sn NMR spectroscopic analysis, and, except for 15 and 18 , single‐crystal X‐ray diffraction studies.     

Zum Reaktionsverhalten lithiierter Aminosilane RR′ Si(H)N(Li)SiMe3

The Reaction Behaviour of Lithiated Aminosilanes RR′Si(H)N(Li)SiMe₃ The bis(trimethylsilyl)aminosubstituted silances RR′Si(H)N(SiMe₃)₂ 11 – 16 (R,R′ = Me, Me₃SiNH, (Me₃Si)₂N) are obtained by the reaction of the lithium silylamides RR′Si(H)N(Li)SiMe₃ 1 – 10 (R,R′ = Me₃SiNLi, Me, Me₃SiNH, (M₃Si)₂N) with chlorotrimethylsilane in the polar solvent tetrahydrofurane (THF). In the reaction of the lithium silylamides [(Me₃Si)₂N]₂(Me₃SiNLi)SiH 10 with chlorotrimethylsilane in THF the rearranged product 1,1,3-tris[bis(trimethylsilyl)amino]-3-methyl-1,3-disila-butane [(Me₃Si)₂N]₂Si(H)CH₂SiMe₂N(SiMe₃)₂ 17 is formed. The reaction of the lithium silyamides RR′ Si(H)N(Li)SiMe₃ 1 – 3 (1: R = R′ = Me; 2: R = Me, R′ = Me₃SiNH; 3: R = Me, R′ = Me₃SiNLi) with chlorotrimethylsilane in the nonpolar solvent n-hexane gives the cyclodisilazanes [RR′ Si? NSiMe₃]₂ 18 – 22 (R = Me, Me₃SiNH, (Me₃Si)₂N; R′ = Me, Me₃SiNH, (Me₃Si)₂N, N(SiMe₃)Si · Me(NHSiMe₃)₂) and trimethylsilane. The lithium silylamides 4 , 5 , 6 , 9 , 10 (4: R = R′ = Me₃SiNH; 5: R = Me₃SiNH, R′ = Me₃SiNLi; 6: R = R′ = Me₃SiNLi; 9: R = (Me₃Si)₂N, R ′ = Me₃SiNLi; 10: R = R′ = (Me₃Si)₂N) shows with chlorotrimethylsilane in n-hexane no reaction. The crystal structure of 17 and 21 are reported.     

Synthesis of Functional Monosilanes by Disilane Cleavage with Phosphonium Chlorides

The Müller–Rochow direct process (DP) for the large-scale production of methylchlorosilanes Me_nSiCl_4−n (n=1–3) generates a disilane residue (Me_nSi₂Cl_6−n, n=1–6, DPR) in thousands of tons annually. This report is on methylchlorodisilane cleavage reactions with use of phosphonium chlorides as the cleavage catalysts and reaction partners to preferably obtain bifunctional monosilanes Me_xSiH_yCl_z (x=2, y=z=1; x,y=1, z=2; x=z=1, y=2). Product formation is controlled by the reaction temperature, the amount of phosphonium chloride employed, the choice of substituents at the phosphorus atom, and optionally by the presence of hydrogen chloride, dissolved in ethers, in the reaction mixture. Replacement of chloro by hydrido substituents at the disilane backbone strongly increases the overall efficiency of disilane cleavage, which allows nearly quantitative silane monomer formation under comparably moderate conditions. This efficient workup of the DPR thus not only increases the economic value of the DP, but also minimizes environmental pollution.     

Reaction of iodo(trimethyl)silane with <Emphasis Type="Italic">N,N</Emphasis>-dimethyl carboxylic acid amides

The reactions of iodo(trimethyl)silane with N,N-dimethylformamide and N,N-dimethylacetamide Me₂NCOR (R = H, Me) at a molar ratio of 1: 2 involved mainly cleavage of the N-C(=O) bond with formation of up to 80% of N,N-dimethyltrimethylsilylamine Me₃SiNMe₂ and the corresponding acyl iodide RCOI. In the reaction with N,N-dimethylformamide, formyl iodide HCOI was detected for the first time by gas chromatography-mass spectrometry. The contribution of Me-N bond cleavage, leading to N-methyl-N-trimethylsilyl derivative Me(Me₃Si)NCOR and methyl iodide was considerably smaller. Another by-product was the corresponding N-methyl imide MeN(COR)₂ formed by reaction of the initial amide with acyl iodide. The primary intermediate in the reaction of iodo(trimethyl)silane with DMF and DMA is quaternary ammonium salt [Me₂(Me₃Si)N⁺COR] I⁻ which decomposes via dissociation of the N-CO and N-Me bonds.     

1‐Silacyclopent‐2‐enes and 1‐silacyclohex‐2‐enes bearing functionally substituted silyl groups in 2‐positions. Novel electron‐deficient Si?H?B bridges

The reactions of alkyn‐1‐yl(vinyl)silanes R₂Si[C?C‐Si(H)Me₂]CH?CH₂ [R = Me (1a), Ph (1b)], Me₂Si[C?C‐Si(Br)Me₂]CH?CH₂ (2a), and of alkyn‐1‐yl(allyl)silanes R₂Si[C?C‐Si(H)Me₂]CH₂CH?CH₂ (R = Me (3a), R = Ph (3b)] with 9‐borabicyclo[3.3.1]nonane in a 1:1 ratio afford in high yield the 1‐silacyclopent‐2‐ene derivatives 4a, b and 5a, and the 1‐silacyclohex‐2‐ene derivatives 6a, b, respectively, all of which bear a functionally substituted silyl group in 2‐position and the boryl group in 3‐position. This is the result of selective intermolecular 1,2‐hydroboration of the vinyl or allyl group, followed by intramolecular 1,1‐organoboration of the alkynyl group. In the cases of 4a, b, potential electron‐deficient Si? H? B bridges are absent or extremely weak, whereas in 6a,b the existence of Si? H? B bridges is evident from the NMR spectroscopic data (¹H, ¹¹B, ¹³C and ²⁹Si NMR). The molecular structure of 4b was determined by X‐ray analysis. Copyright © 2005 John Wiley & Sons, Ltd.     

Homolytic reactions of <Emphasis Type="Italic">N</Emphasis>-bromohexamethyldisilazane with trialkyl(phenylalkoxy) derivatives of silicon and tin

The main product of the photoinduced reaction of N-bromohexamethyldisilazane with trialkyl-(benzyloxy)derivatives of silicon and tin R₃MO(CH₂) _n Ph (R = Me, Et; M = Si, Sn; n = 1) is N,N-dibenzylidene-C-phenylmethanediamine (hydrobenzamide). For M = Si, with increase of the length of the methylene chain between the oxygen atom and the phenyl group (n = 2, 3), the similar reaction affords the product of bromination of the benzylic carbon atom R₃MO(CH₂) _n−1CHBrPh. For M = Sn, the reaction results in the formation of 2-phenyloxacycloalkanes PhCHO(CH₂) _n−1.     

Zur reaktion von metall-koordiniertem kohlenmonoxid mit yliden: XI. Einige neuartige η1-vinyl-komplexe des eisens durch deprotonierung kationischer carbenkomplexe mit trimethyl(methylen)phosphoran

Novel η¹-vinyl complexes of the type Cp(CO)(L)FeC(OMe)C(R)R′ (R = R′ = H, Me; R = H, R′ = Me; L = Me₃P, Ph₃P) are obtainied via methylation of the acyl complexes Cp(CO)(L)FeC(O)R (R = Me, Et, i-Pr) with MeOSO₂F and subsequent deprotonation of the resulting carbene complexes [Cp(CO)(L)FeC(OMe)R]SO₃F with the phosphorus ylide Me₃PCH₂. The same procedure can be applied for the synthesis of the pentamethylcyclopentadienyl derivative C₅Me₅(CO)(Me₃P)FeC(OMe)CH₂, while treatment of the hydroxy or siloxy carbene complexes [Cp(CO)(L)FeC(OR)Me]X (R = H, Me₃Si; X = SO₃CF₃) with Me₃CH₂ results in the transfer of the oxygen bound electrophile to the ylidic carbon. Some remarkable spectroscopic properties of the new complexes are reported.     

Phenyl(acyloxy)fluorosilanes C6H5Si(OCOR)nF3?n (n = 1, 2) and phenyl(acyloxy)fluorochlorosilanes C6H5Si(OCOR)FCl

The method of synthesis of the hitherto unknown class of organosilicon compounds, phenyl(acyloxy)fluorosilanes C₆H₅Si(OCOR) _n F_3−n (n = 1, 2) and phenyl(acyloxy)fluorochlorosilanes C₆H₅Si(OCOR) FCl in up to 91% yield has been developed based on the reaction of phenyl(fluoro)chlorosilanes C₆H₅SiCl _n F_3−n (n = 1, 2) with trimethylsilyl esters of carboxylic acids Me₃SiOC(O)R [R = H, CH₃, CF₃, CCl₃, ClCH₂, BrCH₂, CH₂=CHCH₃, CH₂=CHPh, CH(CH₃)=CH₂, Ph].     

Reactivity of Yttrium Carboxylates Toward Alkylaluminum Hydrides

Yttrocene‐carboxylate complex [Cp*₂Y(OOCAr^Me)] (Cp*=C₅Me₅, Ar^Me=C₆H₂Me₃‐2,4,6) was synthesized as a spectroscopically versatile model system for investigating the reactivity of alkylaluminum hydrides towards rare‐earth‐metal carboxylates. Equimolar reactions with bis‐neosilylaluminum hydride and dimethylaluminum hydride gave adduct complexes of the general formula [Cp*₂Y(μ‐OOCAr^Me)(μ‐H)AlR₂] (R=CH₂SiMe₃, Me). The use of an excess of the respective aluminum hydride led to the formation of product mixtures, from which the yttrium‐aluminum‐hydride complex [{Cp*₂Y(μ‐H)AlMe₂(μ‐H)AlMe₂(μ‐CH₃)}₂] could be isolated, which features a 12‐membered‐ring structure. The adduct complexes [Cp*₂Y(μ‐OOCAr^Me)(μ‐H)AlR₂] display identical ¹J(Y,H) coupling constants of 24.5 Hz for the bridging hydrido ligands and similar ⁸⁹Y NMR shifts of δ=?88.1 ppm (R=CH₂SiMe₃) and δ=?86.3 ppm (R=Me) in the ⁸⁹Y DEPT45 NMR experiments.     

2,2‐Difluor‐1,3‐diaza‐2‐sila‐cyclopenten – Synthese und Reaktionen

2,2‐Difluor‐1,3‐diaza‐2‐sila‐cyclopentene – Synthesis and Reactions N,N′‐Di‐tert‐butyl‐1,4‐diaza‐1,3‐butadiene reacts with elemental lithium under reduction to give a dilithium salt, which forms with fluorosilanes the diazasilacyclopentenes 1 – 4 ; (HCNCMe₃)₂SiFR, R = F ( 1 ), Me ( 2 ), Me₃C ( 3 ), N(CMe₃)SiMe₃ ( 4 ). As by‐product in the synthesis of 1 , the tert‐butyl‐amino‐methylene‐tert‐butyliminomethine substituted compound 5 was isolated, R = N(CMe₃)‐CH₂‐CH = NCMe₃. 5 is formed in the reaction of 1 with the monolithium salt of the 1,4‐diaza‐1,3‐butadiene in an enamine‐imine‐tautomerism. 1 reacts with lithium amides to give (HCNCMe₃)₂SiFNHR, 6 – 12 , R = H ( 6 ), Me ( 7 ), Me₂CH ( 8 ), Me₃C ( 9 ), H₅C₆ ( 10 ), 2,6‐Me₂C₆H₃ ( 11 ), 2,6‐(Me₂CH)₂C₆H₃ ( 12 ). The reaction of 12 with LiNH‐2.6‐(Me₂CH)₂C₆H₃ leads to the formation of (HCNCMe₃)₂Si(NHR)₂, ( 13 ). In the presence of n‐BuLi, 12 forms a lithium salt which looses LiF in boiling toluene. Lithiated 12 adds this LiF and generates a spirocyclic tetramer with a central eight‐membered LiF‐ring ( 14 ), [(HCNCMe₃)₂Si(FLiFLiNR)]₄, R = 2,6‐(Me₂CH)₂C₆H₃. ClSiMe₃ reacts with lithiated 12 to yield the substitution product (HCNCMe₃)₂SiFN(SiMe₃) R, ( 15 ). The crystal structures of 1 , 5 , 6 , 9 , 11 , 13 , 14 are reported.     

Gallium Methylene

Despite the eminent importance of metal alkylidene species for organic synthesis and industrial catalytic processes, molecular homoleptic metal methylene compounds [M(CH₂)_n] as the simplest representatives, have remained elusive. Reports on this topic date back to 1955 when polymeric [Li₂(CH₂)]_n and [Mg(CH₂)]_n were accessed by pyrolysis of methyllithium and dimethylmagnesium, respectively. However, the insoluble salt‐like composition of these compounds has impeded their application as valuable reagents. We report that rare‐earth metallocene methyl complexes [(C₅Me₅)₂Ln{(μ‐Me)₂GaMe₂}] (Ln=Lu, Y) trigger the formation of homoleptic gallium methylene [Ga₈(μ‐CH₂)₁₂] from trimethylgallium [GaMe₃] (Me=methyl) via a cascade C?H bond activation involving the dodecametallic clusters [(C₅Me₅)₆Ln₃(μ₃‐CH₂)₆Ga₉(μ‐CH₂)₉] as crucial intermediates. Such gallium methylene compounds feature a reversible [Ga₈(μ‐CH₂)₁₂]/[Ga₆(μ‐CH₂)₉] oligomer switch in donor solvents and act as Schrock‐type methylene‐transfer reagents.     

Oligodimethylsilane Initiators for Photochemical Vulcanization of Siloxane Rubber

Photolytic vulcanization of siloxane rubber films in the presence of trimethylsiloxy-substituted di- and trisilanes, oligodimethylsilanosiloxanes (Me₂SiO) _m (SiMe₂) _n , Me(Me₂SiO) _m (SiMe₂) _n Me, oligodimethylsilanes Me(Me₂Si) _n Me, and volatile pyrolysis products of polydimethylsilane was studied.     

Ionic Dissociation of SiCl4: Formation of [SiL6]Cl4 with L=Dimethylphosphinic Acid

Reactions of SiCl₄ with R₂PO(OH) (R=Me, Cl) yield compounds with six-fold coordinated silicon atoms. Whereas R=Me afforded the hexacoordinated tetra-cationic silicon complex [Si(Me₂PO(OH))₆]⁴⁺ with chloride counter-ions, R=Cl caused release of HCl with formation of a cyclic dimeric silicon complex [Si(Cl₂PO(OH))(Cl₂PO₂)₃(μ-Cl₂PO₂)]₂ with bridging bidentate dichlorophosphates.     

Synthese und Struktur eines Pentaalkylchlorohexastibans Sb6R5Cl [R = (Me3Si)2CH]

Synthesis and Structure of Pentaalkylchlorohexastibane Sb₆R₅Cl [R = (Me₃Si)₂CH] The reaction of RSbCl₂ [R = (Me₃Si)₂CH] with Na‐K alloy in tetrahydrofuran gives besides the known rings Sb_nR_n (n = 3, 4), (Me₃Si)₂CH₂ and the pentaalkylchlorohexastibane Sb₆R₅Cl ( 1 ). 1 was characterized by spectroscopic methods (MS, ¹H‐, ¹³C‐NMR, X‐ray diffraction). The structure of 1 consists of a folded four membered antimony ring in the all‐trans configuration with three alkyl groups and one Sb(R)—Sb(R)Cl fragment as substituents.     

SYNTHESIS AND NMR CHARACTERIZATION OF P-VINYL SUBSTITUTED PHOSPHAZENE PRECURSORS1

Abstract

The reactions of either PhPCl₂ or PCl₃ with (Me₃Si)₂NLi followed by H₂C[dbnd]CHMgBr were used to prepare the new P-vinyl substituted [bis(trimethylsilyl)amino]phosphines, (Me₃Si)₂NP(R)CH[dbnd]CH₂ [1: R=Ph, 2: CH[dbnd]CH₂, 3: R=Me, and 4: R=N(SiMe₃)₂]. Oxidative bromination of phosphines 3–1 afforded the P-bromo-P-vinyl-N-(trimethylsilyl)phosphoranimines, Me₃SiN[dbnd]P(CH[dbnd]CH₂)(R)Br [5: R=Ph, 6: R=CH[dbnd]CH₂, 7: R=Me], which, upon treatment with CF₃CH₂OH/Et₃N, were subsequently converted to the P-trifluoroethoxy derivatives, Me₃SiN[dbnd]P(CH[dbnd]CH₂)(R)OCH₂CF₃ [8: R=Ph, 9: R=CH[dbnd]CH₂, 10: R=Me]. Compounds 1–10, which are of interest as potential precursors to P-vinyl substituted poly(phosphazenes), were fully characterized by elemental analyses (except for the thermally unstable P-Br derivatives 5–7) and NMR spectroscopy (¹H, ¹³C, and ³¹P) including complete analysis of the vinylic proton splitting patterns via HOM2DJ experiments.     

Oxo(trisyl)boran (Me3Si)3C?BO als Zwischenstufe

Oxo(trisyl)borane (Me₃Si)₃C? B?O as an Intermediate The acyclic trisylboranes R? B(OSiMe₃)? Cl ( 4 a ) and R? B(OH)? H ( 5 a ) and the cyclic boranes (? RB? O? CO? CO? O? ) ( 1 a ) and (? RB? O? RB? O? SO₂? O? ) ( 6 a ) [R = (Me₃Si)₃C, “Trisyl”] are thermolyzed in the gasphase to give well-defined products. The tris(trisyl)boroxine (? RB? O? )₃ ( 2 a ) is formed from 4 a and 5 a at 140 and 160°C, respectively, besides Me₃SiCl and H₂, respectively, whereas the six-membered ring [? BMe? CH(SiMe₃)? SiMe₂? O? SiMe₂? CH₂? ] ( 8 ) is the product from 1 a and 6 a at 600 and 700°C, respectively, besides CO/CO₂ and SO₃, respectively. The oxoborane R? B?O is presumably a common intermediate. It is stabilized at the lower temperature by cyclotrimerization to give 2 and at the higher temperature by a sequence of several intramolecular steps: a 1,3-silyl shift along the chain C? B? O, an exchange of Me and Me₃SiO along the chain Si? C? B, and a C? H addition to the B?C double bond; the steps can be rationalized by analogous known reactions. The gas-phase thermolysis at 600°C of the dioxaboracyclohexenes (? BR? O? CR′ = CH? CRR′? O? ) ( 7 b? d ; R = Me, iPr, tBu; R′ = Me) yields the boroxines (RBO)₃ and the enones Me? CO? CH?CHR? Me; the cyclohexene 7 e (R = Me; R′ = CF₃) is not decomposed at 600°C.     

Synthesis and Complexation Study of New Aminoalkynyl−amidinate Ligands

The current library of amidinate ligands has been extended by the synthesis of two novel dimethylamino-substituted alkynylamidinate anions of the composition [Me₂N−CH₂−C≡C−C(NR)₂]⁻ (R = ⁱPr, cyclohexyl (Cy)). The unsolvated lithium derivatives Li[Me₂N−CH₂−C≡C−C(NR)₂] ( 1 : R = ⁱPr, 2 : R = Cy) were obtained in good yields by treatment of in situ-prepared Me₂N−CH₂−C≡C−Li with the respective carbodiimides, R−N=C=N−R. Recrystallization of 1 and 2 from THF afforded the crystalline THF adducts Li[Me₂N−CH₂−C≡C−C(NR)₂] ⋅ nTHF ( 1 a : R = ⁱPr, n=1; 2 a : R = Cy, n=1.5). Precursor 2 was subsequently used to study initial complexation reactions with selected di- and trivalent transition metals. The dark red homoleptic vanadium(III) tris(alkynylamidinate) complex V[Me₂N−CH₂−C≡C−C(NCy)₂]₃ ( 3 ) was prepared by reaction of VCl₃(THF)₃ with 3 equiv. of 2 (75 % yield). A salt-metathesis reaction of 2 with anhydrous FeCl₂ in a molar ratio of 2 : 1 afforded the dinuclear homoleptic iron(II) alkynylamidinate complex Fe₂[Me₂N−CH₂−C≡C−C(NCy)₂]₄ ( 4 ) in 69 % isolated yield. Similarly, treatment of Mo₂(OAc)₄ with 3 or 4 equiv. of 2 provided the dinuclear, heteroleptic molybdenum(II) amidinate complex Mo₂(OAc)[Me₂N−CH₂−C≡C−C(NCy)₂]₃ ( 5 ; yellow crystals, 50 % isolated yield). The cyclohexyl-substituted title compounds 2 a , 4 , and 5 were structurally characterized through single-crystal X-ray diffraction studies.     

Acyl iodides in organic synthesis. Reaction of acetyl iodide with thiols

The direction of reactions of acetyl iodide with aliphatic, aromatic, and heterocyclic thiols is determined by the thiol acidity and steric factors. Acetyl iodide reacted with aliphatic thiols, including trialkylsilylsubstituted derivatives R(CH₂) _n SH (R = Me, n = 3; R = Me₃Si, n = 3; R = Et₃Si, n = 2), to give the corresponding ethanethioates R(CH₂) _n SCOMe. Benzenethiol was oxidized with acetyl iodide to diphenyl disulfide. The reaction of acetyl iodide with 2-sulfanylethanol afforded 2-(2-iodoethyldisulfanyl)ethyl acetate as a result of three consecutive-parallel processes: acylation, iodination, and oxidation of the initial compound. 1,3-Benzothiazole-2-thiol reacted with acetyl iodide only at the nitrogen atom to give quaternary salt, whereas the SH group remained intact.     

Reaktionen des tBu(Me3Si)P?P(Li)?P(tBu)2 mit CH3Cl und 1,2-Dibromethan

Reactions of tBu(Me₃Si)P? P(Li)? P(tBu)₂ with CH₃Cl and 1,2-Dibromoethane tBu(Me₃Si)P? P(Li)? P(tBu)₂ · 0.95 THF 1 with CH₃Cl (?70°C) yields tBu(Me₃Si)P? P = P(Me)(tBu)₂ 2 at ?70°C, with 1,2-Dibromoethane tBu(Me₃Si)P? PBr? P(tBu)₂ 3 (main product) and tBu(Me₃Si)P? P?P(Br)tBu₂ 4. 3 eliminates Me₃SiBr yielding the cyclotetraphosphane {tBuP? P[P(tBu)₂]}₂ 5 .