Substitution reactions involving organoaluminum compounds

The reaction of ,-dichloro- and ,-diacetoxysulfides with dialkyl-Z-alkenylalanes has been studied; reaction occurs under mild conditions with retention of Z-configuration in the double bond. The reaction represents a stereospecific method for the synthesis of cyclic Z-homoallyl sulfides. The corresponding cycloalkanes and cycloalkenes can be obtained from these Z-homoallylic sulfides by desulfurization with Li in ethylamine or with Raney nickel.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1869–1874, August 1989.     

Synthesis of some unsaturated organoaluminum compounds

Summary The following unsatmated organoaluminum compounds were prepared in the form of ether complexes: tri-allylaluminum, tri-2-butenylaluminum, tri-3-butenylaluminum, and tri-4-pentenylaluminum.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1222–1225, July, 1964     

Efficient halogenation of unsaturated organoaluminum compounds with sulfonyl halides

Alkenylalumanes prepared by carbo-or cycloalumination of substituted acetylenes reacted with an equivalent amount of sulfonyl halide (MsCl, TsCl, PhSO₂Cl, MsBr) in methylene chloride or hexane at room temperature to produce alkenyl halides in high yields. Electron-donor solvents such as diethyl ether or tetrahydrofuran inhibited the halogenation process. β-Substituted vinylalumanes generated by hydroalumination of substituted acetylenes failed to react with sulfonyl halides.     

ZrCl4-Catalyzed scission of ethylene acetals with organoaluminum compounds

Ethylene acetals and ethylene ketals undergo reductive scission under the action of Buⁱ ₂AlH in the presence of catalytic amounts of ZrCl₄. With Et₃Al and Buⁱ ₃Al, reductive alkylation also occurs. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1550–1552 August, 1999.     

Cationic organoaluminum compounds as intramolecular hydroamination catalysts

Cationic dialkylaluminum and m-terphenylalkylaluminum compounds catalyze the intramolecular hydroamination of primary and secondary aminopentenes. The reaction rates are strongly dependent on the substrate and the catalyst substituents. The bulky species [Dipp1AlEt][CHB₁₁H₅I₆] (Dipp1 = 2,6-Dipp₂C₆H₃–, Dipp = 2,6-iPr₂C₆H₃–), 4, was the most active catalyst. Although the neutral species DcpAlEt₂ (Dcp = 2,6-(2,6-Cl₂C₆H₃)₂C₆H₃–), 7, and Dipp1AlEt₂, 8, showed some catalytic activity, they were more than 25 times less reactive than their cationic counterparts [DcpAlEt][CHB₁₁H₅Cl₆], 3, and 4. The cyclization of secondary benzylaminopentenes with [Et₂Al][CHB₁₁H₅I₆], 1, was strongly dependent on the substitution of the C-2 olefinic carbon.     

Cationic organoaluminum compounds as intramolecular hydroamination catalysts

Cationic dialkylaluminum and m-terphenylalkylaluminum compounds catalyze the intramolecular hydroamination of primary and secondary aminopentenes. The reaction rates are strongly dependent on the substrate and the catalyst substituents. The bulky species [Dipp1AlEt][CHB₁₁H₅I₆] (Dipp1 = 2,6-Dipp₂C₆H₃–, Dipp = 2,6-iPr₂C₆H₃–), 4, was the most active catalyst. Although the neutral species DcpAlEt₂ (Dcp = 2,6-(2,6-Cl₂C₆H₃)₂C₆H₃–), 7, and Dipp1AlEt₂, 8, showed some catalytic activity, they were more than 25 times less reactive than their cationic counterparts [DcpAlEt][CHB₁₁H₅Cl₆], 3, and 4. The cyclization of secondary benzylaminopentenes with [Et₂Al][CHB₁₁H₅I₆], 1, was strongly dependent on the substitution of the C-2 olefinic carbon.     

Regiospecific cleavage of 1,3-dioxanes by organoaluminum compounds

Organoaluminum compounds react with 4-methyl-2-phenyl-1,3-dioxane with cleavage of the O₁-C₂ bond to give monoethers with a primary alcohol group.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1036–1037, August, 1985.     

Preparation of cyclopropane hydrocarbons via organoaluminum compounds

Summary Cyclopropane hydrocarbons are formed in good yields by the thermal decomposition of the products of the addition of dialkylaluminum hydrides to substituted alkyl allyl ethers.     

Active centers on the surface of thermoactivated silica. Their reactivity toward organoaluminum compounds

Interaction between organoaluminum compounds (triethylaluminum, ethoxydiethylaluminum, and diethoxyethylaluminum) and the surface of silica activated at various temperatures (200–800 °C) was studied by IR spectroscopy, mass spectrometry, and quantum chemistry. Formation of structural silanon defects on the surface of silica activated at 800 °C was considered. It was established that the fraction of terminal silanol groups involved in the interaction with organoaluminum compounds on the surface of silica thermoactivated above 600 °C is low, and siloxane bonds and structural surface defects play a determining role. The thermodynamic favorability of coordination of organoaluminum compounds on these active surface centers is shown. The structure and routes of decomposition of aluminum-containing surface intermediates were studied.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1906–1911, October, 1995.The work was financially supported by the Russian Foundation for Basic Research (Project No. 94-03-08847).     

Application of hydroalumination reactions in organic syntheses. coupling reactions of organoaluminum compounds with allylic halides catalyzed by copper compounds

Hydroalumination of olefins with lithium aluminum hydride followed by treatment with various allylic halides in presence of a catalytic amount of copper(I) chloride resulted in coupling. This new development provides a simple operational method for lengthening the carbon chain of olefins.     

Alkylation of phenol by nerol in the presence of organoaluminum compounds

Alkylation of aluminum phenolate by nerol and of phenol by nerol in the presence of the organoaluminum compounds aluminum phenolate and aluminum isopropylate was studied. The reaction products were isolated and characterized. Several features of the process were determined. It was found that ortho-substitution of the aromatic ring occurred primarily. In several instances nerol was cyclized. The fraction of allyl rearrangement was insignificant.     

Reductive pinacol-type rearrangement of chiral α-mesyloxy ketones promoted by organoaluminum compounds

Reductive pinacol-type rearrangement of chiral α-mesyloxy ketones was effected by organoaluminums (DIBAL in combination with Et₃Al or Et₂AlCl) leading to enantiomerically pure 2-aryl- or 2-alkenyl-1-propanols.