Reductions that give a product which itself can be reduced further can be difficult to achieve. For example, it is very difficult to reduce a carboxylic acid only to the aldehyde since the aldehyde can be (and usually is) reduced further to the primary alcohol. Tri-tert-butoxyaluminum hydride to the rescue! This wonderful reagent will reduce acyl chloride to aldehydes without further reduction of the aldehyde to the alcohol. The model shown contains methyl groups in place of the tert.-butyl groups to save computer time.