Tetrahydrofuran Tetramethylethylenediamine

The strong inductive effect of the fluoro substituents in 1,1-difluorobenzocyclopropene increases the acidity of the aromatic protons. The compound was deprotonated with butyllithium in tetrahydrofuran/tetramethylethylenediamine at — 95 C at C2, and the metalated derivative was intercepted with electrophiles. This sequence allowed the preparation of a series of mono-and disubstituted 1,1-difluorobcnzocyclopropenes 1 and 2. ... 

Dichloro(propene) (/i,/ )-AW -dimethyl-MV -bis(a-methylbenzyl)-l,2-ethanediamme platinum (n) Pt, M5/> )2 2.148(29), trigonal bipyramidal, propene ligand disordered Benzophenonedilithium tetrahydrofuran tetramethylethylenediamine Li, 2.244— 2.578,... 

Abbreviations Aik, alkyl AN, acetonitrile Ar, aryl Bu, butyl cod, 1,5-cyclooctadiene Cp, cy-clopentadienyl Cp , pentamethylcyclopentadienyl Cy, cyclohexyl dppm, diphenylphosphinome-thane dpme, Ph2PC2H4PMe2 Et, ethyl fod, 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octane-dionate HOMO, highest occupied molecular orbital LUMO, lowest unoccupied molecular orbital Me, methyl MO, molecular orbital nbd, norbornadiene Nuc, nucleophile OTf, triflate Ph, phenyl Pr, propyl py, pyridine THE, tetrahydrofuran TMEDA V,V,M,M-tetramethylethylenediamine. 

THF THP TIPS TIPSOTf TMEDA TMS TMSC1 TMSCN TMS I TMSOTf Ts tetrahydrofuran tetrahydropyranyl tri-isopropylsilyl tri-isopropylsilyl trifluoromethanesulphonate AVV,N N -tetramethylethylenediamine trimethylsilyl trimethylsilyl chloride (chlorotrimethylsilane) trimethylsilyl cyanide (cyanotrimethylsilane) trimethylsilyl iodide (iodotrimethylsilane) trimethylsilyl trifluoromethanesulphonate tosyl (p-tolucnesulphonyl)... 

NMO NMP Nu PPA PCC PDC phen Phth PPE PPTS Red-Al SEM Sia2BH TAS TBAF TBDMS TBDMS-C1 TBHP TCE TCNE TES Tf TFA TFAA THF THP TIPBS-C1 TIPS-C1 TMEDA TMS TMS-C1 TMS-CN Tol TosMIC TPP Tr Ts TTFA TTN N-methylmorpholine N-oxide jV-methyl-2-pyrrolidone nucleophile polyphosphoric acid pyridinium chlorochromate pyridinium dichromate 1,10-phenanthroline phthaloyl polyphosphate ester pyridinium p-toluenesulfonate sodium bis(methoxyethoxy)aluminum dihydride (3-trimethylsilylethoxy methyl disiamylborane tris(diethylamino)sulfonium tetra-n-butylammonium fluoride f-butyldimethylsilyl f-butyldimethylsilyl chloride f-butyl hydroperoxide 2,2,2-trichloroethanol tetracyanoethylene triethylsilyl triflyl (trifluoromethanesulfonyl) trifluoroacetic acid trifluoroacetic anhydride tetrahydrofuran tetrahydropyranyl 2,4,6-triisopropylbenzenesulfonyl chloride 1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane tetramethylethylenediamine [ 1,2-bis(dimethylamino)ethane] trimethylsilyl trimethylsilyl chloride trimethylsilyl cyanide tolyl tosylmethyl isocyanide meso-tetraphenylporphyrin trityl (triphenylmethyl) tosyl (p-toluenesulfonyl) thallium trifluoroacetate thallium(III) nitrate... 

The submitters have found that the hexane-tetramethylethylenediamine solvent system described above, which is required for toluenesulfonyl-hydrazones, may be replaced with tetrahydrofuran when triisopro-pylbenzenesulfonylhydrazones are used, provided that the electrophilic reagent is added to the vinyllithium species as soon as it is formed (as indicated by cessation of nitrogen evolution). 

Tetramethylethylenediamine, THE, sec-butyllithium, chlorodimethyloctylsilane THE, borane-tetrahydrofuran complex, hydrochloric acid CH2C12, vinyl chloroformate THE, potassium t-butoxide... 

Tetrahydrofuran Tf = Trifluoromethaiiesulfonyl TMEDA = A,Ai,Ai, A -tetramethylethylenediamine TMM = Trimethy-lenemethane TMS = Trimethylsilyl / -Tol = Para-tolyl Ts = j9-toluenesulfonyl UV = Ultraviolet X = Halide. 

All reactions and sample preparations are carried out in an inert-atmosphere enclosure under dry nitrogen. Solvents and reagents are dried in the following manner. Benzene, tetrahydrofuran, and n-pentane are freshly distilled from lithium aluminum hydride pyridine is distilled over barium oxide and tetramethylethylenediamine is distilled over calcium hydride. Solvents used in preparing nmr and infrared samples are degassed by a freeze-thaw technique. Nmr spectra are obtained with torch-sealed nmr tubes. The commercial transition metal carbonyl complexes are recrystallized and vacuum-dried before use. Glassware is routinely flame-dried. 

PhjPCHjCHjPPhCHjCHjPPhCHjCHjPPhj thermogravimetric analysis tetrahydrofuran tetrahydropyran tetrahydrothiophene thin-layer chromatography N,N,N, N -tetramethylethylenediamine, (CH3),N(CHP N(CH3),... 

List of abbreviations bpy, 2,2 -bipyridine dme, dimethoxyethane dmf, dimethylformamide dmpe, bisdimethylphosphinoethane dmpz, bisdi-methylpyrazolyl dppe, bisdiphenylphosphinoethane dppm, bisdiphenylphosphinomethane ophen, or/Ao-phenanthroline PPN. bisftriphenylphos-phine)iminium pic. 4-picoline py, pyridine pz, pyrazolyl thf, tetrahydrofuran tmeda, tetramethylethylenediamine Tol, p-tolyl. 

Table 2 lists the results found for the Grignard reagents investigated. In diethyl ether solution, the Grignard reagents preferentially add to C-1 [2], whereas in tetrahydrofuran (THF) and other solvents C-4 addition dominates [3], It was also reported that the addition of complexing agents such as iV,iV,iV, /V -tetramethylethylenediamine (TMEDA) or hexa-methylphosphoramide (HMPA) in diethyl ether resulted in the reversal of selectivity. 

Solid silylmetallic reagents can be isolated. Evaporation of liq NHj siffords solid reagents, such as Et3GeK pure, solid MejSiLi is prepared by vacuum sublimation and (MejSOjSiLi S THF (tetrahydrofuran) may be recrystallized from pentane and Li(SiPh2)4Li 2 THF from cyclohexane. Crystalline 1 1 adducts, e.g., EtjSiLi-L, are formed by addition of hexamethylphosphoramide (HMPA), tetramethylethylenediamine (TMED), or 1,2-dimethoxyethane (DME) to Et3SiLi in hexane. Solid McjSiLi DME is also known . Isolation of KSiHj, free of solvent and KH is also possible . 

The reaction of EtjSnH with EtjZn results in decomposition with the formation of Zn metal, ethane, tetraethyltin, hexaethylditin and a polymerp The reaction of PhjSnH with EtjZn in pentane or benzene forms metallic Zn. However, when hydrostannolysis is carried out with preformed complexes of Et2Zn or with a complexing solvent, such as 1,2-dimethoxyethane (DME) or tetrahydrofuran (THE), or by using a preformed coordination complex of EtjZn with tetramethylethylenediamine (TMED) or bipy, the bis(triphenyltin)zinc complexes are obtained in high yields under mild conditions (—20° to 0°C)2 ... 

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