Hofmann's Rule implies that steric effects have the greatest influence
on the outcome of the Hofmann
or similar eliminations. The loss of the β-hydrogen occurs preferably
from the most unhindered (least substituted) position [-CH3 >
-CH2-R > -CH(R2)]. The product alkene with fewer
substitutents will predominate.
Ester Pyrolysis also obeys this preference, and the Hofmann Rule is generally followed whenever a reaction passes through a cyclic transition state.
Hofmann's Rule is valid for all intramolecular eliminations and for the Hofmann Elimination. Most bimolecular eliminations will follow Saytzeff's Rule.
Triphosgene and DMAP as Mild Reagents for Chemoselective Dehydration of Tertiary Alcohols
M. O. Ganiu, A. H. Cleveland, J. L. Paul. R. Kartika, Org. Lett., 2019, 21, 5611-5615.