Addition trimethyl aluminium

The Tebbe Reagent is a metal carbenoid prepared from the dimetallomethylene species derived by the reaction of trimethyl aluminium with titanocene dichloride this reagent exhibits carbenoid behaviour after the addition of a catalytic amount of pyridine. The Tebbe Reagent reacts with various carbonyl partners to give the product of methylenation ... 

Heats of addition reactions. Aluminium and gallium trimethyl... 

Functionalised enones are also compatible with this methodology and easily undergo stereoselective copper-catalysed conjugate addition with trimethyl-aluminium reagents in the presence of phosphoramidite ligand L3. Thus, 1 can be converted by treatment with MesAl into the chiral ketone 2 (95% ee), which can be... 

For the aluminium addition compounds, where there will be little zl-bonding, the order of decreasing donor strength of the Group VI ligands is 0>S>Se>Te. This is the order which is expected if only o -bonds are involved. For the gallium trimethyl compounds the order is changed to /S e Te. This reversal... 

Phosphine oxide complexes with aluminium or gallium trimethyl can be made by direct addition to the etherate (9.159), while dimeric phosphinate complexes can be made by slowly adding a benzene solution of a phosphinic acid to a trialkyl aluminium (9.160, 9.161) [11,12]. Large cages are obtained in Equations 9.162 and 9.163 [13,14]. Compounds (9.164) have Ga-O-P linkages. 

Several new syntheses of vinylsilanes have been described. Tris(trimethyl-silyl)aluminium undergoes 5yn-addition to alkynes alternatively the same -isomers can be obtained by photochemical isomerisation of Z-1-alkenyl-silanes. Other methods described involve treatment of the lithium salts of hydrazones with trimethylsilyl chloride, Wurtz-type coupling with vinyl bromides, and reaction of acetylenes with a silyl-copper reagent followed by an electrophile. Using the hydrazone method, a route has been devised for 1,2-carbonyl transposition within ketones (Scheme 17). ... 

An etched 0.5 g aluminium sample is spiked with a standard solution of boron enriched in B (1.202 10 at.B/g B = 88.06 at.%), and dissolved in 2 ml concentrated nitric acid (suprapur) at 70 C under addition of 1 ml hydrochloric acid (suprapur) every 10 to 15 minutes in order to prevent excessive foaming. After addition of 6 ml hydrochloric acid a clear solution is obtained. To this solution 10 g methanol (purified by distillation over a mixture of sodium hydroxide and mannite) is added, and boron is distilled at 95°C in the form of trimethyl borate. After dilution to 20 ml with water and addition of 2 Mg mannite, the solution is evaporated down to 0.5-1 ml at 60°C. 

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