STEREOCHEMISTRY OF ADDITION OF METHYLCADMIUM AND METHYLZINE REAGENTS TO 4-T-BUTYLCYCLOHEXANONE

Reactivity and stereochemistry were used as criteria for comparison of the methyl reagents, of Mg, Cd, and Zn toward 4-t-butylcyclohexanone. Characteristic differences in the behavior of all three were observed as a function of concentration and halide ion present. The greater amount of axial attack by Cd and Znre agents, compared with Mg reagents, is rationalized as arising from tighter, four-center transition states for the first two. The results fit a steric-approach control consistent with models proposed by Marshall and Felkin. © 1969, American Chemical Society. All rights reserved.