Dimethyl aluminum

Dimethyl aluminum hydride, (CH3)2A1H or DMAH (preferred reaction). 

To mitigate the problem, a diffusion barrier is incorporated between the aluminum and the silicon (see Sec. 5 below). It is also possible to replace aluminum by alloys of aluminum and copper or aluminum and silicon, which have less tendency to electromigration. These alloys are usually deposited by bias sputtering. However, they offer only a temporary solution as electromigration will still occur as greater densities of circuit elements are introduced. It was recently determined that improvements in the deposition of aluminum by MOCVD at low temperature with a dimethyl aluminum hydride precursor may reduce the problem.bl... 

Compound 13a can been obtained via two different routes firstly in the reaction of 11 with dimethyl aluminum chloride where LiCl is eliminated and secondly by the reaction of di(pyridyl) phosphane 12 (Py2PH) with trimethyl aluminum where methane is formed, (Scheme 5). The X-ray structure determination of [Me2AlPy2P] 13a, (Fig. 3) elucidates the aluminum atom to be coordinated by the two nitrogen atoms of the pyridyl rings in addition to the two remaining methyl groups leaving the aluminum four... 

Recently, stable organometallic compounds derived from Ni(acac)2 have been described. The square planar compounds [Ni(acac)(PR3)L] (R = Ph, Cy L = Me, Et) were obtained by reacting Ni(acac)2 and PR3 in ether at -20 °C with either diethyl- or dimethyl-aluminum monoethoxide.1546,1547,1577 [Ni(acac)(Me)PPh3] reacts with diphenylacetylene at room temperature, according to equation (183).1578... 

The redistribution reaction in lead compounds is straightforward and there are no appreciable side reactions. It is normally carried out commercially in the liquid phase at substantially room temperature. However, a catalyst is required to effect the reaction with lead compounds. A number of catalysts have been patented, but the exact procedure as practiced commercially has never been revealed. Among the effective catalysts are activated alumina and other activated metal oxides, triethyllead chloride, triethyllead iodide, phosphorus trichloride, arsenic trichloride, bismuth trichloride, iron(III)chloride, zirconium(IV)-chloride, tin(IV)chloride, zinc chloride, zinc fluoride, mercury(II)chloride, boron trifluoride, aluminum chloride, aluminum bromide, dimethyl-aluminum chloride, and platinum(IV)chloride 43,70-72,79,80,97,117, 131,31s) A separate catalyst compound is not required for the exchange between R.jPb and R3PbX compounds however, this type of uncatalyzed exchange is rather slow. Again, the products are practically a random mixture. 

Dimethylamine chlordimefoim, chloromethiuron, chloroxuron, chlorotoluron, crimidine, dichlofluanid, dicrotophos, difenoxuron, dimefuron, dimethirimol, diphenamid, diuron, fenothiocarb, fenuron, ferbam, fluometuron, hexazinone, isoproturon, karbutilate, metoxuron, metribuzin, monuron, nicosulfuron, oxamyl, pirimicarb, pyrithiobac, thiram, tolyfluanid, triazamate, ziram 4 Dimethyl amino aniline fenaminosulf 2 Dimethyl amino 1,3 dichloro propane bensultap, thiocyclam N-N -Dimethylamino dimethyl aluminum nicosulfuron 2 Dimethyl amino 1,3 Dithiobenzyl propane thiocyclam 4 Dimethyl amino 3 methyl phenol aminocarb... 

METHYLENATION Alkyidimesitylboranes. p,-Chlorobis(cyclopentadienyl)(dimethyl-aluminum)-p.-methylene-titanium. Methylene bromide-Zinc-Titanium(IV) chloride. Organomolybdenum reagents. Titanocene methylene-Zn halide complex. N,N,P-Tri-methyl-P-phenylphosphinothioic amide. Trimethylstannylmethyllithium. 

One of the characteristic features of this approach is the successful fert-alkyl-al-kynyl coupling with dialkylaluminum alkynides which enables the introduction of a quaternary carbon in a position adjacent to an alkynyl group. Such transformation was previously achieved by the cross-coupling of ferf-alkyl chlorides with trialkynyl-aluminums as already described in this section [92]. The reaction of 98 with dimethyl-aluminum phenylacetylide (1.5 equiv.), readily prepared from lithium phenylacetylide and Me2AlCl, in toluene at -78 °C for 30 min resulted in formation of a cross-coupling product in 70 % yield. This result indicates the efficient and selective transfer of the alkynyl group from the aluminum center in dialkylaluminum alkynides as depicted in Sch. 65. 

AMIDES FROM ESTERS WITH DIMETHYL ALUMINUM AMIDES... 

Sulfoxide-magnesium exchange on the a-chloroalkyl sulfoxide 42 was performed with ethylmagnesium bromide followed by trapping with benzaldehyde-dimethyl-aluminum chloride, to furnish 99% of the sulfoxide 43 with 99% ee. Chlorohydrins 44 were obtained in 56% yield as a 94 6 diastereomer mixture. After conversion to the epoxide 45, the latter had an ee of >98% (Scheme 3.18). 

In dehalogenating the phenylaluminum chlorides with sodium it is best to work with xylene as solvent. The complex salts which are formed as an intermediate react further at above 100°C. Triphenylalane is obtained in high yield in this way from the corresponding phenylaluminum chlorides, but the compound usually contains some chlorine. A substantially better method for preparing pure triphenylalane is by the reaction of dimethyl-aluminum chloride with sodium phenyl the resulting dimethylphenylalane disproportionates on distillation at reduced pressure to pure triphenylalane and trimethylalane (171) ... 

The dimeric dicyclopentadienyl methyl yttrium complex reacts readily with methyl aluminum dichloride with loss of the methyl group and formation of a stable di- u-chloro-bridged dicyclopentadienyl yttrium dimethyl aluminum complex (Holton et al., 1979c), and dicyclopentadienyl yttrium chloride reacts with aluminum hydride in ether with formation of a white crystalline 2 1 1 complex, of which the X-ray structure was determined (Lobkovskii et al., 1982) ... 

CioHi8Ga2N, Pyrazolylgallium dimethyl dimer, 41B, 779 Cl0H22AIN, Trimethyl(quinuclidine)aluminum, 37B, 409 C1 0H2 iiAl2N2 r (Isopropylideneamino)dimethylaluminum dimer, 40B, 678 CioH2ftAl2Nii, (N,N, N , N -Tetramethyl-oxalamidinato)-bis (dimethyl-aluminum), 45B, 789... 

C1 (,H2 2AIY, Bis (cyclopentadienyl)yttrium-di-M"inethyl-(dimethyl-aluminum), 44B, 663... 

Protective Groups and Their Removal - Lactones and esters may be protected as IjS-d-tth-iolanes. The ester or lactone is treated with bis (dimethyl-aluminum) 1,2-ethanedithlolate, and deprotection is achieved with mercuric oxide and BF3 Et20 in 15% aqueous THF. The dithiolanes were shown to be stable to acetic acid, to KOH-aqueous methanol, and to LiAlHi, or methyl-lithium in ether. 

Related Reagents. Diethylaluminum Chloride Dimethyl-aluminum Chloride Lithium Tetrafluoroborate Magnesium Bromide. 

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