Organoaluminum amides

Two of the mechanisms for aluminum amide formation assume the formation of an alane-amine adduct and, from a structural point of view, such Lewis pairs have been extensively studied. For instance, the treatment of AIMe3 with Ph(tBuCH2)NH in hexane at room temperature yielded a monomeric adduct Ph(rBuCH2)NH(AlMe3) 

Ring expansion reactions involving A1 amido compounds have recently been performed via insertion of acetonitrile into preexisting Al-N ring structures. Thus, 

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This reaction has been further extended to the asymmetrization of the symmetric acetal, and to different modified organoaluminum reagents including i-BuaAl and bulky organoaluminum amides (Sch. 57) [85],... 

Yamamoto and Maruoka found that organoaluminum amides are highly effective in the Fischer indole synthesis. In particular, DATMP is the reagent of choice for regioselective Fischer indole synthesis [120]. For instance, treatment of the E)-N-methyl-A-phenylhydrazone of 5-methyl-3-heptanone (123) with DATMP affords 3- ec-butyl-2-ethyl-l-methylindole (125) as the sole isolable product its (Z) isomer gives l,3-dimethyl-2-(2-methylbutyl)indole (124) with high regioselectivity under similar reaction conditions, as illustrated in Sch. 84. 

Ceramic powders of exceptional purity with very fine particle sizes (ca. 10 nm) have been prepared by precipitation of hydrolyzed oxides from high purity alkoxides . Yttria-stabilized zirconia is prepared by mixing high purity zirconium and yttrium isopropoxides in n-hexane, with water added dropwise to precipitate the oxides quantitatively. The homogeneity of the oxides results in stabilized cubic Zr02 at very low temperatures. Cyclic organoaluminum amides are used to prepare nonoxides such as sulfides and AIN- . 

For a recent example of a regioselective Fischer indole reaction mediated by organoaluminum amides, see Maruoka, K. Oishi, M. Yamamoto, H. J. Org. Chem. 1993, 58, 7638. 

The presence of both donor and acceptor binding sites in organoaluminum amides makes them ideally suited for supramolecular self-assembly by dative bonding. Indeed, aminoalanes can occur either as monomeric molecules, 51, or as cyclic dimeric, 52, or trimeric, 53, supermolecules [R2A1NR R"] [n — 1,2, or 3), depending mostly on the steric properties of the organic groups. 

EPOXIDES Alumina. r-Butyldimethyl-iodosilane. n-Butyllithium-Magnesium bromide. Cyclohexylisopropylamino-magnesium bromide. Dialkylaluminum amides. lodotrimethylsilane. Lithium l-a,a -dimethyldibenzylamide. Nafion-H. Organoaluminum compounds. Pyri-dinium chloride. Raney nickel. Tti-fluoroacetyl chloride, lrimethylsilyl-acctonitrile. Tris(phenylscleno)borane. Zinc iodide. 

It is noteworthy that acetone reacts with the organoaluminum in a manner quite different from aldehyde to form mesityloxide and acid amide. This dehydrodimerization reaction of acetone is identical with that observed between A1R3 and ketone. That a hydrogen atom bonded to a nitrogen atom of the product originates from that of the methyl group in acetone was proved by using acetone-d6 as a reactant. 

Jennings,J.R., Wade,K., Wyatt,B.K. Reactions between organoaluminum compounds and N-substituted add amides. J. Chem. Soc. A. 1968, 2535. 

Norephedrine, 200 Organoaluminum reagents, 202 Organotitanium reagents, 213 9-(Phenylseleno)-9-borabicyclo-[3.3.1]nonane, 245 Tin(II) chloride, 298 Titanium(IV) chloride, 304 Trityllithium, 338 Trityl perchlorate, 339 Zinc chloride, 349 By other reactions Chloromethyl ethyl ether, 75 Dibutyltin oxide, 95 Samarium(II) iodide, 270 Tributyltin hydride, 316 Hydroxy amides a-Hydroxy amides... 

Scheme 42 Reactivity of lanthanide amide complexes with organoaluminum or borate reagents...

The hydrolysis of these organoaluminum compounds results in the formation of A-alkylcarbonic amides R NHCOR 223). 

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