The Discovery-Oriented Approach to Organic Chemistry. 6. Selective Reduction in Organic Chemistry: Reduction of Aldehydes in the Presence of Esters Using Sodium Borohydride

Chemoselective reductions are valuable in organic synthesis and are routinely discussed in a sophomore organic chemistry course. Yet, there are very few examples of laboratory experiments that illustrate such chemoselectivity. We have developed two discovery oriented lab experiments that illustrate the chemoselective reduction of aldehydes in the presence of esters using NaBH4. The experiments involve the reduction of vanillin acetate and methyl 4-formylbenzoate, using sodium borohydride, followed by product identification using 1H and 13C NMR spectroscopy. Product identification is also achieved by classical qualitative functional group tests. The added element of discovery insures that student interest and enthusiasm are retained.