Effects of a Polar Substituent and Heteroatoms in the Ring

TABLE 5.9 Cis / Trans Isomer Ratios of the Alcohols formed in Hydrogenation of Methoxy- and Methylcyclohexanones  

The results shown in Table 5.11 show that the addition of hydrogen from the equatorial side is hindered by the presence of the ring oxygen or nitrogen atom. The results have been explained by a similar intramolecular interaction effect of the lone-pair electrons of oxygen or nitrogen atom. 

TABLE 5.11 Percent Alcohols Formed by Addition of Hydrogen from Equatorial Side0  

Thc ketone (0.5 mmol) was hydrogenated in ethanol (3 ml) at room temperature and atmospheric hydrogen pressure. 

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