Trigonal planar molecule carbonyl group

Figure 5.15 illustrates the stereochemical aspects of this reaction. Because butanone is achiral, there is no difference in presentation of either face of the molecule to the surface of the metal catalyst. The two faces of the trigonal planar carbonyl group interact with the metal surface with equal probabdity. Transfer of the hydrogen atoms from the metal to the carbonyl group produces a chirality center at carbon 2. Since there has been no chiral influence in the reaction pathway, the product is obtained as a racemic mixture of the two enantiomers, (7 )-(—)-2-butanol and (5)-(+)-2-butanol. 

Structure of the Carboxyl Group The structure of the most stable conformation of formic acid is shown next. The entire molecule is approximately planar. The sp2 hybrid carbonyl carbon atom is planar, with nearly trigonal bond angles. The O—H bond also lies in this plane, eclipsed with the C=O bond. 

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