Tetramethylethylenediamine adduct

Palenih, G. ]. The Crystal Structure of the Aluminium Hydride-N,N,N N -Tetramethylethylenediamine Adduct. Acta Cryst. 17, 1573 (1964). 

Fig. 14. Molecular structure of the tetramethylethylenediamine adduct of trisftrimethyl-silyl)cyclopentadienyllithium, (Me3Si)3H2C5Li(tmeda) (147).

Heteronuclear 2D H Li Nuclear Overhauser Effect (HOESY) spectrum for the tetramethylethylenediamine adduct of 2-lithio-l-phenylpyrrole. Reproduced with permission from [44]. Copyright Wiley-VCH Verlag GmbH Co. KGaA. 

Tetramethylethylenediamine adduct [ 15556-49-7]. Chloro N,, W,N -tetramethyl-l, 2-ethanediamine-N, N ) triphenylstannyl)cadmi um. 

The method does not require optically pure a-pinene because 100% enantiomeric excess (ee) is achieved by crystallisation of the intermediate TMEDA-2IpcBH2 adduct, where TMEDA = (CHg )2NCH2CH2N(CH3 )2 (tetramethylethylenediamine). Other chiral monoalkylboranes derived from 2-alkyl- and 2-phenylapopinene are slightly more selective reagents as compared to monoisopinocampheylborane (66—68). 

Dimethyl- and diethylzinc reacted with dimethylpyrrole- and mesityl-substituted cyclopentadiene ligands to give monocyclopentadienyl(methyl)zinc and -ethyl(zinc) compounds. These products then formed, Scheme 20, crystalline adducts with tetramethylethylenediamine (TMEDA) such as 24, whose solid-state structure is shown in Figure 11. 

Experimental observations support these views. Photolysis of 1-naphthylazide in the presence of diethylamine and tetramethylethylenediamine (TMEDA) yields azirine, but no ketenimine-derived adducts at ambient temperature. " In the presence of diethylamine but in the absence of TMEDA, good yields of 1-amino-naphthalene and 1,1 -azo-naphthalene, products attributable to the triplet nitrene are observed. Good yields of 46 are also achieved when the photolysis of 1-naphthylazide and diethylamine is performed at —60 °C in the absence of TMEDA. Presumably, lowering the temperature extends the hfetime of azirine 43 by reducing its rate of reversion to singlet 1-naphthylnitrene more than it retards the rate of its reaction with diethylamine. 

The adducts of (Me3Si)3H2CjLi with the nitrogen bases quinuclidine [N(CH2CH2)3CH], tetramethylethylenediamine (tmeda, Me2NCH2CH2N-Me2), and pentamethyldiethylenetriamine [pmdeta, Me2NCH2CH2N-... 

Hydroboration of 1 followed by treatment with tetramethylethylenediamine (TMEDA), as described by Brown,4 afforded enantiomerically pure complex 2, which was then converted in three steps to monoisopinocampheylcyanoborane (3). This compound was directly reacted with phosphines 4, leading to the corresponding adducts 5 and 6 (Table 1). The yields reported are from the TMEDA adduct 2. 

In the course of our studies of oligosilyl anions we have investigated alternative conditions for the generation of oligosilyl potassium compounds [4]. For example, we have employed tetramethylethylenediamine (tmen) / toluene solvent mixtures to obtain the tris(trimethylsilyl)silyl potassium (1) and l,l,4,4-tetrakis(trimethylsilyl)-2,2,3,3-tetramethyltetrasilanyl 1,2-dipotassium (2) tmen adducts (Eqs. 1,2). 

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 electrochemical oxidation of Cd in the presence of PhjSnCl in CHjCN-benzene and in the presence of tetramethylethylenediamine (TMED) and bipy yields the corresponding adducts PhjSnCdCTTMED (in 30% yield), and PhjSnCdCl-bipy (in 43 % yield), respectively ... 

The discovery of the temperature dependence of the photochemistry of phenyl azide prompted Leyva and Platz [85] to reexamine the photochemistry of 1-naphthyl azide. As mentioned previously photolysis of 1-naphthyl azide at 298 K in the presence of diethylamine fails to produce an azepine adduct, instead only a trace of diamine 9 is observed along with small amounts of azonaphthalene [51, 57, 91], The major product is 1-naphthy-lamine. Carroll et al. [51] improved the yield of diamine adduct with piperidine by adding N, N, N, N tetramethylethylenediamine (TMEDA) to complex with singlet 1-naphthyl nitrene. TMEDA did not improve the yield of diethylamine adduct, however. 

Recently, Connell et al. have found that, by using a catalytic amount of 4-dimethylaminopyridine (DMAP) as a nucleophile in the presence of an equal amount of tetramethylethylenediamine (TMEDA) and Mgl2, MBH adducts can be obtained in good to excellent yields from various aromatic and aliphatic aldehydes and cyclic enones/enoates at room temperature after convenient reaction times (Scheme 2.218). ... 

In 1998 Boudjouk et al. published similar results [3] for the reaction of trichlorosilane with tetraethylethylenediamine (teeda) or tetramethylethylenediamine (tmeda), showing that a 1 1 adduct is formed with or without previous dismutation, yielding SiH2Cl2-teeda or SiHCla-tmeda, respectively. 

The tin(II) enolate prepared from (1), tin(II) trifluoromethane-sulfonate, and 1-ethylpiperidine reacts with aldehydes in the presence of A(, fY,fV -tetramethylethylenediamine (TMEDA) to afford the anti aldol adducts in good yields with good selectivities (eq 1). Interestingly, syn selective reactions proceed in the absence of TMEDA. Optically active antf aldol adducts can be obtained in the presence of chiral diamine (2) instead of TMEDA. 

Alternatively, borinane is precipitated selectively from the reaction mixture as its bis adduct with either N,N,Ar,Ar-tetramethylethylenediamine (TMEDA) or 1,4-diazabicyclo [2.2.2] octane (DABCO) in nonpolar solvents like hexane. However, the bis adducts of both 9-BBN and borinane precipitate, quantitatively, from the hexane solution of the boranes at 0 °C. Fortunately, there is a large kinetic difference between the rates of adduct formation 9-BBN takes a couple of hours to react with difunctional amines, whereas borinane reacts almost instantaneously. Thus, this selective reaction affords almost quantitative precipitation of the bis adduct of borinane with TMEDA and DABCO (Scheme 17.3) [6]. 

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