LACK OF STERIC HINDRANCE AND STEREOELECTRONIC CONTROL IN PROTON REMOVAL FROM 4,4-DISUBSTITUTED CYCLOHEXANONES

Comparison of the rates of base-catalyzed deuterium exchange at the a positions of 4,4-diphenyl-, 4-methyl-4-phenyl-, and 4,4-dimethylcyclohexanones with that of cyclohexanone itself failed to reveal steric hindrance to proton abstraction by the 4-axial substituents. Since the original evidence for stereoelectronic control in proton abstraction is based on the assumption that the steric effect of a 4-axial substituent is substantial, these results cast doubt on the importance of this factor. © 1968, American Chemical Society. All rights reserved.