Reactivity of hydride-transfer reducing agents

LiAIH4 alcohol alcohol alcohol alcohol alcohol amine 

LiAKt-BuOljH aldehyde alcohol alcohol very slow aldehyde 

Hydride reductions of carboxylic acid derivatives such as conversion of esters to alcohols involve elimination steps in addition to hydride transfer. In the case of 

One of the more difficult selective reductions to accomplish is the conversion of a carboxylic acid derivative to an aldehyde without overreduction to the alcohol. Several approaches have been used to achieve this selectivity. One is to replace some of the hydrides by bulky groups, thus modifying reactivity by steric factors. Lithium tri-t-butoxyaluminum hydride is an example of this approach. This reagent is prepared by addition of an appropriate quantity of t-butanol to LiAlFL. As noted in 

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Table 4.1. Reactivity of Hydride-Transfer Reducing Agents...

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