ORIENTATION IN BASE-PROMOTED 1,2-ELIMINATION REACTIONS - NITROGEN AND CARBON BASES

Orientation in 1, 2-eliminations from 2-iodobutane promoted by a variety ofnitrogen and carbon bases in dimethyl sulfoxide has been determined. By variation of the base counterion from sodium to potassium then potassium in the presence of 18-crown-6, the importance of ion pairing for nitrogen and carbon bases was explored. Using linear free energy relationships, we demonstrated that sensitivity of positional orientation to base strength variation is the same for amide ion and oxyanion bases. However, for methide ion bases, the sensitivity of positional orientation to base strength change was very dependent upon the base type. Copyright © 1979, American Chemical Society. All rights reserved.