last updated 04/22/99

Use the following steps to determine the major product for this exercise:

STEP 1 - FORMATION OF THE CARBOCATION: draw the resulting carbocation formed in this reaction and determine if it will undergo a carbocation rearrangement

STEP 2: FORMATION OF THE ALKENE FROM THE CARBOCATION: the most substituted alkene is most likely to be formed

Example Problem: Predict what the major product would be for the following dehydration.

SOLUTION:

STEP 1: FORMATION OF THE CARBOCATION

initially this carbocation is formed:

a primary carbocation (help)

However, the above primary carbocation rearranges to a more stable form (why?)

STEP 2: FORMATION OF THE ALKENE FROM THE CARBOCATION

The elimination of the hydrogen has two possible pathways:

	2,3-dimethyl-1-butene (minor product)
	2,3-dimethyl-2-butene (major product)

"Path b" is favored because of Zaitsev's Rule. Thus the major product is 2,3-dimethyl-2-butene