In-text-exercises on Enols and Enones
Exercise 18-1 and 18-2 are soo easy; just read over it.
Do exercises 18-3 and 18-4 and remember that O-protonation is involved.
Do exercise 18-5 to review control mono- vs. polyhalogenation by choice of catalyst.
Exercise 18-6 points out an important point:
The enolate is a nucleophile and also a base.
As a nucleophile, enolate will do SN2 with R-X and you get C-alkylation.
As a base, enolate will eliminate HX from the RX. In this case, the enolate will go back to the ketone and the RX is turned into HX and olefine.
Which path is taken depends on the nature of the RX:
Primary RX: SN2 only. Secondary RX: SNs and E2. Tertiary RX: E2 only.
Skip exercise 18-7.
Exercise 18-9 is a good one. Do it well. Also consider why the alkylation never happens at the other alpha position. Can you find out the pKa difference between these positions.
Exercises 18-10 through 18-16 all are very easy, don't you think?
Exercise 18-17 is important and will be discussed in the lecture.
Review nucleophilic additions to electron-deficient double bonds by solving exercises 18-19 through 18-21.
Exercises 18-22 and 18-23 are important and will be discussed in lecture.
Selected Problems to Chapter 18
Problem 3 reviews mono- vs. polyhalogenation (again).
Problem 4 is a good one and repeats the message of exercise 18.6!
Study problems 5 (a only) and 7 together.
Review aldol reactions with problem 10.
Skip 11 - 13.
Problem 14 but only for cyclohexenone.
Problem 17 part c.
Problem 18 part c.
Skip all others except for problems 22 and 25.
That's it for now, friends.
There are will be GTQs for this chapter.