Complexation of dichlorocarbene by methylanisoles

Dichlorocarbene generated by laser flash photolysis of dichlorodiazirine readily forms UV-vis active π- and O-ylidic complexes with methylanisole derivatives.     

The synthesis of dichlorodiazirine and the generation of dichlorocarbene: spectroscopy and structure of dichlorocarbene ylides

Reaction of 2,4-dinitrophenoxychlorodiazirine (13) with chloride ions affords dichlorodiazirine (4). Photolysis of 4 generates dichlorocarbene. In laser flash photolysis (LFP) experiments, CCl2 forms chromophoric ylides or oxides with pyridine, 2-picoline, thioanisole, and oxygen. Spectroscopic and computational studies of the ylides are reported. The UV spectrum of CCl2 in solution, however, is not observed. It appears possible that CCl2 is rapidly captured by oxygen to afford a chromophoric dichlorocarbene carbonyl oxide. We present a theoretical analysis of this process.     

The reaction between 2,5-dialkylpyrroles and dichlorocarbene

An intermediate in the reaction between pyrrole 1 and dichlorocarbene-PhHg⁺, has been isolated, and its structure determined by X-ray diffraction. This compound can be converted into 3-chloropyridine and 2H-pyrrole under the action of acids and/or bases.     

Reaction of dichlorocarbene with vinyl sulfides

Conclusions The reaction of dihalocarbenes with vinyl sulfides gave gem-dihalocyclopropyl sulfides. The relative activity of the sulfides toward dichlorocarbene is 5–6 times greater than that of the corresponding ethers. The theory was expressed that intermediate sulfur ylides are formed in the given reaction.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1354–1358, June, 1980.     

Reaction of nitroxyl radicals with dichlorocarbene

Conclusions The reaction of aromatic nitroxyl radicals with dichlorocarbene, generated under phase transfer catalysis conditions, leads to the corresponding hydrazine derivatives through the abstraction of the oxygen atom from the nitroxyl radicals and formation of aminyl radicals.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 470–472, February, 1989.     

Addition of dichlorocarbene to vinyl ethers

Conclusions Addition reactions between dichlorocarbene and vinyl ethers were carried out for the first time.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 149–153, January, 1967.We thank É. I. Kositsyna and N. I. Golovanova for determining the spectra.     

1,4-Addition of dichlorocarbene to 1,2-bismethylenecycloheptane

The reaction of dichlorocarbene with 1,2-bismethylenecycloheptane $\text{3}$ yields, besides the 1,2-addition product $\text{4b}$, the 1,4-addition product $\text{6b}$ in a ration 99:1.     

Photoisomerization of dichlorocarbene adducts of 2,4-cyclohexadienones

Irradiation of the nπ* band of the dichlorocyclopropyl enones $\text{1}$ and $\text{7}$ resulted in ring expansion and 1,2-chlorine migration to give $\text{2}$ and $\text{8}$ respectively, whereas the dihydrogen analog $\text{11}$ gave the vinylcyclopropane-cyclopentene rearrangement product $\text{12}$.     

A search for dichlorocarbene ether solvent interactions

The absolute rate constant of reaction of dichlorocarbene with pyridine and with tetramethylethylene was determined in Freon-113 (CF₂ClCFCl₂), dioxane, and tetrahydrofuran. No evidence of specific solvation was obtained.     

Sequential trapping of dichlorocarbene and dichlorocarbonyl ylides

The thermal decomposition of phenyl (bromodichloromethyl)-mercury in the presence of aryl aldehydes and dimethyl acetylenedicarboxylate leads to the formation of dimethyl 2-halo-5-arylfuran-3, 4-dicarboxylates by selective trapping of the intermediate dihalocarbonyl ylides.     

Photodissociation dynamics of dichlorocarbene at 248 nm

The dynamics of the 248 nm photodissociation of the CCl(2) molecule have been investigated in a molecular beam experiment. The CCl(2) parent molecule was generated in a molecular beam by pyrolysis of CHCl(3), and both CCl(2) and the CCl photofragment were detected by laser fluorescence excitation. The 248 nm attenuation cross sections was estimated from the reduction of the CCl(2) signal as a function of the photolysis laser fluence. The internal state distribution of the CCl photofragment was derived from analysis of laser fluorescence excitation spectra in the A (2)Delta- X (2)Pi band system. The CCl(X (2)Pi, nu = 0) rotational state distribution was found to be bimodal, with maximum populations at N approximately 10 and 85, and was dependent upon the source backing pressure, and hence upon the internal state distribution of the CCl(2) precursor. The 248 nm photodissociation dynamics appears to involve two separate channels, namely nearly impulsive rotational energy release and predissociation with little rotational energy imparted to the CCl fragment.     

Mechanisms of single-electron capture by the dichlorocarbene dication

The single-electron capture (SEC) by dichlorocarbene dications with eight different atomic and molecular target gases, CCl ₂ ²⁺ + G → CCl ₂ ⁺ + G⁺, has been studied by product ion spectroscopy and ion kinetic energy spectroscopy. The experimental data have been interpreted in the framework of a theoretical model mat describes the charge exchange process. Exothermic charge exchange is handled within the Landau-Zener model, whereas endothermic charge exchange is described by the Demkov model. The calculated data reproduce qualitatively the essential features of the experimental results: (1) the appearance of a reaction window centered at an exothermicity in the 4–4.5-eV range, (2) the lower SEC cross sections for endothermic charge exchange, (3) the wider internal energy distributions obtained for CCl ₂ ⁺ in the endothermic regime than in the exothermic one, which results in larger dissociation yields, (4) the excitation of molecular targets that accompany their ionization in the SEC process, and (5) the kinetic energy released on the CCl⁺ + Cl fragments in dissociative SEC.     

Dichlorodiazirine: a nitrogenous precursor for dichlorocarbene

The reaction of 3-p-nitrophenoxy-3-chlorodiazirine with a 1.1:1.0:1.6 blend of tetrabutylammonium chloride, cesium chloride, and the ionic liquid 1-butyl-3-methylimidazolium chloride at 40-50 degrees C under vacuum at 1 mm.Hg produced a melt from which dichlorodiazirine distilled into a cold trap containing pentane at -70 degrees C over 6-7 h. Dichlorodiazirine, the first nitrogenous precursor for dichlorocarbene, was reasonably stable in the dark at 25 degrees C and efficiently generated the carbene upon photolysis.     

The reaction between 2,3-dialkylindoles and dichlorocarbene

A zwitterionic intermediate in the reaction between 2,3-dimethylindole and dichlorocarbene-PhHgl, has been detected and converted into 3-chloroquinoline 3 and 3$\text{H}$-indole 4. This suggests the existence of a single intermediate for both products.