Lithium triethoxyaluminum hydride nitriles

Lithium triethoxyaluminum hydride is a more powerful reagent which reduces tert-amides and nitriles to the corresponding aldehydes. ... 

These relatively mild reducing agents can reduce the carbonyl of a lactone to give a lactol. In one example, 75 (an intermediate in Magnus synthesis of grandisol) was isolated in 97% yield when 74 was reduced with lithium triethoxyaluminum hydride at -20°C. It is known that trialkoxyaluminum hydrides will reduce aldehydes, ketones, esters and acid chlorides before reducing nitriles and amides. 

Nitriles can be reduced to amines by either catalytic hydrogenation or lithium aluminum hydride. However, the modified hydride reagent lithium triethoxyaluminum hydride adds to the bond only once to give an imine anion derivative. 

Several reduction methods are available to convert nitriles (Stephen reaction) or acyl chlorides (Rosenmund reduction) or amides to aldehydes. The use of lithium aluminum hydride at low temperatures or lithium triethoxyaluminum hydride appears to be a more effective means of reduction than the stannous chloride-HCl used in the Stephen method or palladium and hydrogen used in the Rosenmund reduction. 

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