MECHANISMS II Final2007 (200Points) Name

MECHANISMS II Final2007 (200points) Name

1) (15pts) Define these four terms:

-FREE RADICAL

-FREE RADICAL INITIATOR

-FREE RADICAL INHIBITOR

-CHAIN PROCESS

List the 5 types of reactions that radicals can perform. (Hint: the reaction types start with A, A, D, D, and F)

2) (15pts) 2-Propanol is a very good hydrogen atom donor.

a) Draw the product of hydrogen abstraction when the hydrogen removed is from:

- the OH

- the CH

- the CH3

b) Which of the three radicals above is the most stable?

c) Briefly explain your choice.

d) Write a fish hook arrow mechanism showing how the t-butoxyl radical would react with 2-propanol to yield t-Butanol and the radical you picked in (b).

3) (8pts) The following hexenyl radical can react intramolecularly to generate two different cyclic radicals.

a) Number the corresponding carbons in the product radicals.

b) Identify whether the cyclizations were EXO or ENDO.

c) write mechanisms for both cyclizations.

4) Draw a Lewis structure of a radical species that you believe would have an unusually high stability, and a significantly long lifetime. (4pts)

b) Why are special measures taken to remove air from almost all radical reactions? (2pts)

c) Name one gas commonly used as an inert atmosphere for radical reactions. (2pts)

d) Name a good inert organic solvent for radical reactions. (2pts)

5) (20pts) What do these Mass Spectrometry terms stand for?

APCI

QQQ

MALDI

EI

HPLC

ESI

HRMS

TOF

(MS)2

AMU

6) Indicate which electron is most easily removed (by EI) from the following molecules (10pts).

7) Write a chemical equation showing a reaction that strongly implies that carbon centered radicals are planar (or quickly inverting shallow pyramidal) structures.

(5pts)

b) Propose a mechanism for this photochemical reaction (10pts).

8) (7pts) Write the mechanism for the interaction of a free radical initiator, tributyl tin hydride and alkyl bromide, which results in the formation of the corresponding alkyl radical.

b) Write mechanisms for both these reactions with Chlorine. (10 pts)

Questions (9-15)

Write mechanisms for 6 of the following 7 transformations (6 x 15 = 90)

9) Write the mechanism for the following chain reaction. (15pts)

10) Write the mechanism for the following reaction. (15pts)

11) Write the mechanism for the following reaction. (15pts)

12) Write the mechanism for the following reaction. (15pts)

13) Write the mechanism for the following reaction. (15pts)

14) Write the mechanism for the following reaction. (15pts)

15) Write the mechanism for the following reaction. (15pts)

2007 - MechII -Final1