Chemical Properties
Lithium tri-tert-butoxyaluminum hydride is a white powder with a melting point of 319°C, which is sublimated under vacuum at 280°C. It is soluble in ethylene glycol dimethyl ether, diglyme and tetrahydrofuran, and slightly soluble in ether. Stable in dry air, hydrolyzed slowly in moist air. Lithium tri-tert-butoxyaluminum hydride is a mild and highly selective reducing agent. Ketones, aldehydes and acid chlorides can be reduced in diethyl ether or diglyme at 0°C, fatty acid esters and nitriles are not reduced, but phenyl esters of fatty acids and alicyclic acids can be reduced.
Uses
Lithium tri-tert-butoxyaluminum hydride is less reactive than lithium aluminum hydride (LAH) and is very useful in selective reductions of acyl halides, aldehydes, ketones, and esters. It is an important raw material and intermediate used in organic synthesis, pharmaceuticals, agrochemicals and dye stuff. LAH, is a reducing agent commonly employed in modern organic synthesis.
Uses
antimicrobial, cholesterol lowering agent, for ion-permeable synthetic membranes
Preparation
Lithium aluminum hydride reacts with tert-butanol in ether to prepare Lithium tri-tert-butoxyaluminum hydride.
LiAlH4+3 (CH3)3COH→LiAlH[OC(CH3)3]
3+3 H2
General Description
Lithium tri-tert-butoxyaluminum hydride is a mild reducing agent mainly used for the selective reduction of ketones. It is very suitable for selective reductions on account of its mild reducing power, the most important of these being the reduction of steroid ketones. In addition to chemical selectivity, a certain stereoselectivity is shown in the reduction of cyclic ketones.
reaction suitability
reagent type: reductant
