Umsetzung von Arsolanen,Arsenanen und Arsepinen mit Oximen

Reaction of Arsolanes, Arsenanes, and Arsepines with Oximes The reaction of methyl-substituted arsolanes, arsenanes and arsepines with oximes results in it opening of the cyclic arsinous acid esters. In the course of the reaction of the substituted arsolanes (CH₂)₂O₂As? X[X = N(CH₃)₂, OCH₃, Cl] and (CH₂)₂ON(CH₃)As? N(CH₃)₂ with oximes the group X is substituted by the oxime; an opening of the rings does not take place.     

Reactions of 1-(3"-Amino)- and 1-(3"-Acetamido)propylsilatranes with Cobalt(II) Chloride and Dicobalt Octacarbonyl

1-(3"-Amino)propylsilatrane (I) and 1-(3"-acetamido)propylsilatrane (II) react with anhydrous cobalt(II) chloride to give dichlorobis[1-(3"-amino)propylsilatrane]cobalt(II) {Co[NH₂CH₂CH₂CH₂Si(OCH₂CH₂)₃N]₂Cl₂} (III) and dichlorobis[1-(3"-acetamido)propylsilatrane]cobalt(II) {Co[CH₃C(O)NHCH₂CH₂CH₂Si(OCH₂CH₂)₃N]₂Cl₂} (IV). Being unstable, compound IV transforms into an imidic acid derivative. Reactions of silatranes I and II with dicobalt octacarbonyl afford hexakis[1-(3"-aminoamido)propylsilatrane]cobalt(II) bis(tetracarbonylcobaltate) {Co[NH₂CH₂CH₂CH₂Si(OCH₂CH₂)₃N]_4.8[HC(O)NHCH₂CH₂CH₂Si(OCH₂CH₂)₃N]_1.2}[Co(CO)₄]₂ (V) and hexakis[1-(3"-acetamido)propylsilatrane]cobalt(II) bis(tetracarbonylcobaltate) {Co[CH₃C(O)NHCH₂CH₂CH₂Si(OCH₂CH₂)₃N]₆}[Co(CO)₄]₂ (VI), respectively. In acetonitrile, tetracarbonylcobaltate anions of compound VI are oxidized with atmospheric oxygen and moisture to cobalt hydroxocarbonate, giving a carbonate gel (VII).     

Synthese und Charakterisierung neuer intramolekular stickstoffstabilisierter Organoaluminium‐ und Organogalliumalkoxide

Synthesis and Characterization of New Intramolecularly Nitrogen‐stabilized Organoaluminium‐ and Organogallium Alkoxides The intramolecularly nitrogen stabilized organoaluminium alkoxides [Me₂Al{μ‐O(CH₂)₃NMe₂}]₂ ( 1a ), Me₂AlOC₆H₂(CH₂NMe₂)₃‐2,4,6 ( 2a ), [(S)‐Me₂Al{μ‐OCH₂CH(i‐Pr)NH‐i‐Pr}]₂ ( 3a ) and [(S)‐Me₂Al{μ‐OCH₂CH(i‐Pr)NHCH₂Ph}]₂ ( 4 ) are formed by reacting equimolar amounts of AlMe₃ and Me₂N(CH₂)₃OH, C₆H₂[(CH₂NMe₂)₃‐2,4,6]OH, (S)‐i‐PrNHCH(i‐Pr)CH₂OH, or (S)‐PhCH₂NHCH(i‐Pr)CH₂OH, respectively. An excess of AlMe₃ reacts with Me₂N(CH₂)₂OH, Me₂N(CH₂)₃OH, C₆H₂[(CH₂NMe₂)₃‐2,4,6]OH, and (S)‐i‐PrNHCH(i‐Pr)CH₂OH producing the “pick‐a‐back” complexes [Me₂AlO(CH₂)₂NMe₂](AlMe₃) ( 5 ), [Me₂AlO(CH₂)₃NMe₂](AlMe₃) ( 1b ), [Me₂AlOC₆H₂(CH₂NMe₂)₃‐2,4,6](AlMe₃)₂ ( 2b ), and [(S)‐Me₂AlOCH₂CH(i‐Pr)NH‐i‐Pr](AlMe₃) ( 3b ), respectively. The mixed alkyl‐ or alkenylchloroaluminium alkoxides [Me(Cl)Al{μ‐O(CH₂)₂NMe₂}]₂ ( 6 ) and [{CH₂=C(CH₃)}(Cl)Al{μ‐O(CH₂)₂NMe₂}]₂ ( 8 ) are to obtain from Me₂AlCl and Me₂N(CH₂)₂OH and from [Cl₂Al{μ‐O(CH₂)₂NMe₂}]₂ ( 7 ) and CH₂=C(CH₃)MgBr, respectively. The analogous dimethylgallium alkoxides [Me₂Ga{μ‐O(CH₂)₃NMe₂}]₂ ( 9 ), [(S)‐Me₂Ga{μ‐OCH₂CH(i‐Pr)NH‐i‐Pr}]_n ( 10 ), [(S)‐Me₂Ga{μ‐OCH₂CH(i‐Pr)NHCH₂Ph}]_n ( 11 ), [(S)‐Me₂Ga{μ‐OCH₂CH(i‐Pr)N(Me)CH₂Ph}]_n ( 12 ) and [(S)‐Me₂Ga{μ‐OCH₂(C₄H₇NHCH₂Ph)}]_n ( 13 ) result from the equimolar reactions of GaMe₃ with the corresponding alcohols. The new compounds were characterized by elemental analyses, ¹H‐, ¹³C‐ and ²⁷Al‐NMR spectroscopy, and mass spectrometry. Additionally, the structures of 1a , 1b , 2a , 2b , 3a , 5 , 6 and 8 were determined by single crystal X‐ray diffraction.     

Schwingungsspektren und Kraftkonstanten von W(OCH3)6, Mo(OCH3)6 und [Sb(CH3)4][Sb(OCH3)6]

Vibrational Spectra and Force Constants of W(OCH₃)₆, Mo(OCH₃)₆, and [Sb(CH₃)₄][Sb(OCH₃)₆] The infrared and Raman spectra of the monomeric hexamethoxides of Tungsten and Molybdenum and of the ionic compound [Me₄Sb]⁺[Sb(OMe)₆]^? (prepared from [Sb(OMe)₅]₂ and Me₄SbOMe; Me = CH₃) are recorded and interpreted on the basis of C_3i symmetry. The force fields of W(OMe)₆ and [Sb(OMe)₆]^? are calculated using the same basis set of force constants. Both W? O- and Sb? O- stretching force constants are identical (2.56 N/cm), however the other parts of the valence force field are markedly different.     

NMR-Untersuchungen an Methylphosphoniumchlorid

N.M.R. Investigation of Methylphosphonium Chloride The n.m.r. spectra of [CH₃PH₃]Cl in aqueous hydrochloric acid as solvent and of [OP(CH₃) (OCH₂CH₂Cl)OCH₂? ]₂ in C₆D₆ und CD₂Cl₂ are described. ³¹P n.m.r. resonances with a line width at half height of 55 Hz are found for the H₂O? HCl solutions of [CH₃PH₃]Cl in the solid state at 183 K.     

Synthesis and characterization of ferrocenylalkoxygermatranes and crystal structures of FcCH2OGe (OCH2CH2)3N and FcCH(CH3)OGe(OCH2CH2)3N1

Germatranes bearing a ferrocenylalkoxyl moiety have been obtained by the reaction of HOGe(OCH₂CH₂)₃N with various ferrocenyl alcohols. A convenient new synthesis method of FcCH₂OGe(OCH₂CH₂)₃N was reported. FcCH₂OGe(OCH₂CH₂)₃N was prepared in 93% yield when FcCH₂OH reacted with HOGe(OCH₂CH₂)₃N in chloroform at room temperature in the presence of molecular sieves (3 Å) as a dehydrating agent. All compounds were characterized by elemental analysis, ¹H NMR and IR spectroscopy. The molecular structures of FcCH₂OGe(OCH₂CH₂)₃N and FcCH(CH₃)OGe(OCH₂CH₂)₃N have been determined by X‐ray diffraction. The antitumor activities of FcCH₂OGe(OCH₂CH₂)₃N and p‐FcC₆H₄CH₂OGe(OCH₂CH₂)₃N were determined. Copyright © 2005 John Wiley & Sons, Ltd.     

Darstellung und Charakterisierung von bindungsisomeren Hexakis(thiocyanato-isothiocyanato)-iridaten(III) und einiger Chloro-, Cyano-pentarhodanoiridate(III)

Preparation and Characterization of Bond-Isomeric Hexakis(thiocyanato-isothiocyanato)-iridates(III) and Some Chloro-, Cyano-pentarhodanoiridates(III) The evaporated ethanolic extract of the reaction product of K₃[IrCl₆] and HNO₃, refluxed with an aqueous KSCN solution yields a mixture of the bond isomers [Ir(NCS)_n(SCN)_6?n]^3?, n = 0–2 and small amounts of bond isomeric chloropentrahodanoiridates(III). By heating the tetrabutylammonium salts, N coordination of the ambident SCN^? is favoured forming compounds with n = 2–5 beside chloro- and cyanopentarhodanoiridates(III). With n = 2, 3 pairs of geometric isomers can be detected. The pure compounds are separated by ion exchange chromatography on diethylaminoethylcellulose. The trans/mer-complexes migrate 1.9 times faster than the cis/fac-isomers. Depending on S- or N-bonding the IR and Raman spectra show typical vibrations: ν_CN(N) and ν_CN(S): 2100–2175, ν_CS(N): 810–855, ν_CS(S): 690–710, δ_NCS: 470–480, δ_SCN: 420–470, ν_IrN: 300–325, ν_IrS: 255–313 cm^?1. Except the inner ligand vibrations the Rh? N and Rh? S valence frequencies are assigned according to the supposed point symmetries. By interaction of the trans-positioned ligands characteristic shifts are caused.     

Heteronuclear Alkoxide Compounds Containing Copper and Alkaline Earth Metals

The tetrameric Cu(β-diketonate) alkoxide complex [Cu(thd)(OCH₂CH₂OCH₃)]₄ (thd = 2,2,6,6-tetramethyl-3,5-heptanedionate; 1a ) reacts with the alkaline earth metal alkoxides [M(OCH₂CH₂OCH₃)₂] (M = Ca, 2a ; M = Sr, 2b ; M = Ba, 2c ) to yield the heteronuclear compounds [Cu₂M(thd)₃(OCH₂CH₂OCH₃)₃] (M = Ca, 6a ; M = Sr, 6b ). These heterometallic complexes were also obtained in the reaction of 1a and the mixed Ca and Sr complexes of β-diketonate-alkoxide [M_x(thd)_y(OCH₂CH₂OCH₃)_2x?y] (M = Ca, x = 7, y = 6, 3 ; M = Sr, x = 5, y = 3, 4 ), respectively. In comparison, 1a reacts with the analogous [Ba(thd)(OCH₂CH₂OCH₃)] ( 5a ) to yield a[Ba₂Cu₂(thd)₄(OCH₃)₄(HOCH₂CH₂OCH₃)₂] species ( 8a .) The in situ prepared mixed-ligand Ba Compounds [Ba(thd)OR)] (R = CH₂CH₂OCH₂CH₂OCH₃, ( 5b ); R = CH₂CH₂CH₂OCH₃ ( 5c ) react with the corresponding Cu complexes [Cu(thd)(OR)]_n (R = CH₂CH₂OCH₂CH₂OCH₃), n = 4 ( 1b ); R = CH₂CH₂OCH₂CH₂OCH₃ ( 8b ); R = CH₂CH₂CH₂OCH₃ ( 8c ). However, [Cu(hfd)(OCH₂CH₂OCH₃)]₄ (hfd = 1,1,1,5,5,5,-hexafluoroacetylacetonate; 1e ) is converted in the presence of 2a–c to the simple metathesis products [M(hfd)₂] (M = Ca, Sr, Ba) and [Cu(OCH₂CH₂OCH₃)₂]. Crystalline [Ba₂Cu₂(hfd)₂(thd)₂(OCH₂CH₂CH₂OCH₃)₄(HOCH₂CH₂CH₂OCH₃)₂] ( 9 ) was isolated from the reaction of 1a with in situ prepared [Ba((hfd)OCH₂CH₂CH₂OCH₃)] ( 5d ) in 2-, methoxyethanol. X-Ray crystallographic structure determinations are reported for 6a , 6b , 8b , and 8c .     

(η5-Divinylboran)metall-komplexe von ruthenium und rhodium

The new complexes Ru(CO)₃[η⁵-(C₂H₃)₂BCl] and [C₅(CH₃)₅]Rh[η⁵-(C₂H₃)₂BX] with XOCH₃, CH₃ and C₆H₅ are described.     

Darstellung und Struktur von Methylphosphoniumchlorid

Preparation and Structures of Methylphosphonium Chloride The reaction between methyldichlorophosphane and glycol in dichloromethane yields [CH₃PH₃]Cl and CH₂[? OP(O)CH₃(OCH₂CH₂Cl)]₂. The molecular and crystal structure of [CH₃PH₃]Cl are reported.     

Gas-phase ion–molecule reactions in dilute mixtures of dimethyl ether in krypton. Bimolecular and clustering reactions

The results of high-pressure variable-temperature and variable ionizing electron energy studies of gas-phase ion-molecule reactions of dimethyl ether in krypton are presented. Near the ionization threshold a series of peaks corresponding to (CH₃OCH₃)_nH⁺ (n = 1-4) clusters are observed. At higher ionizing electron energies, two new series of peaks appear, corresponding to [CH₃OCH₂]⁺(CH₃OCH₃)_n and [(CH₃)₃O]⁺ (CH₃OCH₃)_n clusters. The onium ion, [(CH₃)₃O]⁺, has been previously reported at elevated temperatures under methane chemical ionization conditions. It was suggested that the onium ion is formed by reaction of (CH₃)₂OH⁺ with CH₃OCH₃ with subsequent elimination of methanel, i.e. by fragmentation of an adduct ion. The present results strongly suggest that, under our conditions, [CH₃OCH₂]⁺ rather than thermal (CH₃)₃OH⁺, is the precursor to [(CH₃)₃O]⁺.     

Schwingungsspektren und Kraftkonstanten der Übergangsreihen OP (CH3)3–OP(OCH3)3 und SP(CH3)3–SP(OCH3)3

Vibrational Spectra and Force Constants of the Series OP(CH₃)₃? OP(OCH₃)₃ and SP(CH₃)₃? SP(OCH₃)₃ The vibrational spectra of OP(CH₃)₂(OCH₃), OP(CH₃)(OCH₃)₂, SP(CH₃)₂(OCH₃), and SP(CH₃)(OCH₃)₂, are recorded and assigned to the normal vibration. The valence force constants are calculated by a simplified force field. The results are disscussed for both series and compared with former results.     

Bildung und reaktivität kationischer rhodiummethyl- trimethylphosphit-komplexes;eine weitere metall- organische variante der Michaelis—Arbuzov-reaktion

C₅H₅Rh(P(OCH₃)₃]₂ (I) reacts CH₃I and (CH₃)₃OBF₄ at low temperatures to give [C₅H₅RhCH₃{P(OCH₃)₃}₂]X (II: X = I; III: X = BF₄). Elimination of CH₃I from II yields the phosphonate complex C₅H₅RhCH₃[P(OCH₃)₃]- [P(O)(OCH₃)₂] (IV) which reacts with (CH₃)₃OBF₄ to give III.     

Kupfer(I)-Komplexe mit 1-Azadien-Chelatliganden und ihre Reaktion mit Sauerstoff

Copper(I) Complexes with 1-Azadiene Chelate Ligands and Their Reaction with Oxygen The reaction of the bidendate 1-azadiene ligands Me₂N? (CH₂)_n? N?CH? CH?CH? Ph with CuX results in the formation of the dimeric compounds [ A CuX]₂ and [ B CuX]₂ ( A : n = 2, B : n = 3, X: I, Cl). The structure of complex 1 [ A CuI]₂ was determined by X-ray crystal structure analysis. 1 consists of two tetrahedrally coordinated Cu atoms connected by two iodo bridges. (Cu? Cu bond length: 261 pm). The ligand Me? N(CH₂CH₂N?CH? CH?CH? Ph)₂ ( C ) reacts with CuX to form the monomeric complexes [ C CuX] ( 5 : X?I, 6 : X?Cl). The crystal structure of 5 shows that the ligand acts as a tridendate ligand. The bond lengths of the CuN(sp²) bonds are significantly shorter than the Cu? N(sp³) distance. Reacting the podand-type ligands N(CH₂CH₂? N?CH? R)₃ ( D : R?Ph, E : R?-CH?CH? Ph) with CuX yields the ionic complexes 7 [ D Cu][CuCl₂] and 8 [ E Cu][CuCl₂]. 7 was characterized by X-ray analysis which confirmed that D acts as a four-dendate podand ligand. The compounds 1 ? 8 are unreactive towards CO₂ but take up O₂ even at deep temperatures. At ?78°C the orange-red complex 4 [ B CuCl]₂ reacts with O₂ in CH₂Cl₂ to form a deep violet solution, but the primary product of the oxidation could not be isolated. It reacts at room temperature to form the green complex 9 [μ-Cl, μ-OH][ B CuCl]₂. The X-ray structure analysis of 9 confirms that a dimeric Cu^II complex is formed in which both a chloro- and a hydroxo group are bridging the monomeric units. The Cu^II centers exhibit a distorted tetragonal-pyramidal coordination. The pathway of the reaction with O₂ will be discussed.     

Bis[bis(trimethylsilyl)amino]sulfan 1. Darstellung und Charakterisierung

Inhaltsübersicht. Die Titelverbindung[(CH₃)₃Si]₂N–S–N[Si(CH₃)₃]₂ wurde durch Reaktion von Lithium-bis(trimethylsilyl)arnid mit Schwefeldichlorid hergestellt. Elektronenabsorptions-, Infrarot-, Kernresonanz- (¹H, ¹³C, ²⁹Si, ¹⁵N) und Massenspektren werden mitgeteilt. Die Reaktivität der Verbindung wurde untersucht. Bis[bis (trimethylsilyl) amino] sulfane. 1. Synthesis and Characterization Abstract, The title compound [(CH₃)₃Si]₂N–S–N[Si(CH₃)₃]₂ has been prepared by reaction of lithium bis(trimethylsilyl)amide with sulfur dichloride. Electron absorption, infrared, nuclear magnetic resonance (¹H, ¹³C, ²⁹Si, ¹⁶N), and mass spectra are given. The reactivity of the compound has been studied. Im Zusammenhang mit unseren Untersuchungen [1–3] über S-Bis(trimethyl-eilyl)aminoester von Dithiocarbamidsäuren RR′N–CS–S–N[Si(CH₃)₃]₂ haben wir uns mit dem Bis[bis(trimethylsilyl)amino]sulfan [(CH₃)₃Si]₂N-S-N[Si(CH₃)₃]₂ befaßt. Diese Verbindung wurde erstmals 1962 von Wannagat u. Kückertz [4] hergestellt und kurz beschrieben. Wolmershäuser u. Mitarb. [5] teilten einige wenige spektroskopische Daten mit; vgl. auch [6, 7].     

Ligand‐Modification Effects on the Reactivity,Solubility, and Stability of Organometallic Tantalum Complexes in Water

Tantalum complexes [TaCp*Me{κ⁴‐C,N,O,O‐(OCH₂)(OCHC(CH₂NMe₂)?CH)py}] ( 4 ) and [TaCp*Me{κ⁴‐C,N,O,O‐(OCH₂)(OCHC(CH₂NH₂)?CH)py}] ( 5 ), which contain modified alkoxide pincer ligands, were synthesized from the reactions of [TaCp*Me{κ³‐N,O,O‐(OCH₂)(OCH)py}] (Cp*=η⁵‐C₅Me₅) with HC?CCH₂NMe₂ and HC?CCH₂NH₂, respectively. The reactions of [TaCp*Me{κ⁴‐C,N,O,O‐(OCH₂)(OCHC(Ph)?CH)py}] ( 2 ) and [TaCp*Me{κ⁴‐C,N,O,O‐(OCH₂)(OCHC(SiMe₃)?CH)py}] ( 3 ) with triflic acid (1:2 molar ratio) rendered the corresponding bis‐triflate derivatives [TaCp*(OTf)₂{κ³‐N,O,O‐(OCH₂)(OCHC(Ph)?CH₂)py}] ( 6 ) and [TaCp*(OTf)₂{κ³‐N,O,O‐(OCH₂)(OCHC(SiMe₃)?CH₂)py}] ( 7 ), respectively. Complex 4 reacted with triflic acid in a 1:2 molar ratio to selectively yield the water‐soluble cationic complex [TaCp*(OTf){κ⁴‐C,N,O,O‐(OCH₂)(OCHC(CH₂NHMe₂)?CH)py}]OTf ( 8 ). Compound 8 reacted with water to afford the hydrolyzed complex [TaCp*(OH)(H₂O){κ³‐N,O,O‐(OCH₂)(OCHC(CH₂NHMe₂)?CH₂)py}](OTf)₂ ( 9 ). Protonation of compound 8 with triflic acid gave the new tantalum compound [TaCp*(OTf){κ⁴‐C,N,O,O‐(OCH₂)(HOCHC(CH₂NHMe₂)?CH)py}](OTf)₂ ( 10 ), which afforded the corresponding protonolysis derivative [TaCp*(OTf)₂{κ³‐N,O,O‐(OCH₂)(HOCHC(CH₂NHMe₂)?CH₂)py}](OTf) ( 11 ) in solution. Complex 8 reacted with CNtBu and potassium 2‐isocyanoacetate to give the corresponding iminoacyl derivatives 12 and 13 , respectively. The molecular structures of complexes 5 , 7 , and 10 were established by single‐crystal X‐ray diffraction studies.     

Synthesis und Reaktivität von Dimethylaminoalkylidenaminooxy-arsinen

Synthesis and Reactivity of Dimethylaminoalkylideneaminooxiarsines The reactions of As[N(CH₃)₂]₃ with oximes result in the formation of the oximates [(CH₃)₂N]₂AsONCRR′, (CH₃)₂N As(ONCRR′)₂ and As(ONCRR′)₃. The eleavage of the As-N-bond with alcohols, thiols and diols are described. The reactions of CH₃As[N(CH₃)₂]ONCRR′ with water, amine and alcohols are examined. IR-and ¹H-NMR-spectral data are presented.     

Synthese und Eigenschaften von Bis-[dialkylamino-methylarsino]-methanen

Synthesis and Properties of Bis-[dialkylamino-methyl-arsino]-methanes The reactions of methan-bis-[methyl-chlorarsine] H₂C[As(CH₃)Cl]₂ with secondary amines lead to the formation of bis-[dialkylamino-methylarsino]methanes H₂C[As(CH₃)NR₂]₂. The cleavage of the As? N bond with acid molecules HX (X?OH, OR, SR, NR₂, halogen) results in the formation of the compounds H₂C[As(CH₃)X]₂. The IR and ¹H-NMR spectra are discussed and presented.     

Synthetic and Structural Studies on Some New Butterfly Fe/S Cluster Complexes Containing 2,6-(CH2)2C5H3N or (CH2)2 Groups

Four new butterfly Fe/S cluster complexes bearing 2,6-(CH₂)₂C₅H₃N or (CH₂)₂ groups, as the active site models of [FeFe]-hydrogenase, have been prepared by condensation reaction and structurally characterized. Treatments of the parent complex Fe₂(CO)₆[(μ-SCH₂)₂CHCO₂H] (A) with 2,6-(HOCH₂)₂C₅H₃N or HOCH₂CH₂OH in the presence of 4-dimethylaminopyridine and dicyclohexylcarbodiimide afforded the single-butterfly Fe/S complexes Fe₂(CO)₆[(μ-SCH₂)₂CHC(O)OCH₂(2,6-C₅H₃N)CH₂OH] (1) and Fe₂(CO)₆[(μ-SCH₂)₂CHC(O)OCH₂CH₂OH] (3) and the double-butterfly Fe/S complexes [Fe₂(CO)₆(μ-SCH₂)₂CHC(O)OCH₂]₂(2,6-C₅H₃N) (2) and [Fe₂(CO)₆(μ-SCH₂)₂CHC(O)OCH₂]₂ (4). The new complexes 1–4 were fully characterized by elemental analysis, ESI-MS, IR, and ¹H (¹³C) NMR spectroscopy.     

Der massenspektrometrische Zerfall von Hexamethoxydisilan und Oktamethoxytrisilan

The decomposition (70 eV, 17 eV) of Si₂(OCH₃)₆, Si₂(OCD₃)₆, and Si₃(OCH₃)₈ by electron-impact is characterized by an initial loss of the radicals CH₃, Si(OCH₃)₃, and OCH₃. For the disilanes, a typical pathway follows by successive loss of formaldehyde forming SiH-units; in the trisilane the main fragmentation path shows elimination of dimethoxysilylene previous to CH₂O-abstraction. Fragmentation schemes are given, in part metastable supported.