compared to the corresponding aldehydes in favor of the Felkin product 46 (Scheme 18, Table 8).
The addition of nucleophiles to 3-substituted cyclohexanones has also been analyzed by Felkin and Anh. The underlying concepts in these cases are, however, the distinction between axial attack due to torsional strain and equatorial attack due to the lower steric hindrance of the nucleophile on its incoming trajectory. Since there is no issue of conformational flexibility as found in acyclic R-chiral or â-chiral substrates, such cases should not be considered in the context of Cram’s rule.