| Abstrakt: |
The organotrihydroaluminate [Li(thf )2][(Me3Si)3CAlH3] (thf 4;= 4;tetrahydrofuran) reacted with alcohols R′OH, (R′ 4;= 4;Me, Et, Pri or But), PhOH, aldehydes R1CHO (R1 4;= 4;Me, But or Ph) or ketones R1R2CO (R1 4;= 4;R2 4;= 4;Me or Ph; R1 4;= 4;Me, R2 4;= 4;Ph) to give organotrialkoxoaluminates [Li(thf )n][(Me3Si)3CAl(OR′)3] (n 4;= 4;1, R′ 4;= 4;Me, Pri, But, CH2But, CH2Ph or CHPh2; n 4;= 4;2, R′ 4;= 4;Et or Ph; n 4;= 4;4, R′ 4;= 4;Me), analogues of the intermediates presumed to be present in the reduction of carbonyl compounds by LiAlH4. The structure of [Li(thf )2][(Me3Si)3CAl(OEt)3] was determined by X-ray crystallography which showed that the lithium cation and the organotriethoxoaluminate anion are linked to give a planar LiO2Al ring. The organotrialkoxoaluminates are hydrolysed by traces of water to give organoalkoxohydroxoaluminates and the structure of one of these, {Li[(Me3Si)3CAl(OPri)2(OH)]}2, has been determined. The dimer has an Li2Al2O6 framework comprising two adjacent face-sharing cubes with missing atoms at diametrically opposite corners. Terminal and bridging alkoxo groups in solutions of some of these compounds can be distinguished by NMR measurements. |
