Worksheet 8 Answers PDF

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Worksheet 8 Answers...

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Worksheet 8 1. What does it mean for something to add Markovnikov? Markovnikov addition means that additions to carbon-carbon multiple bonds where one thing being added is hydrogen and the other is a generic R group (halogen, alcohol, etc.), the HYDROGEN adds to the LEAST substituted carbon, therefore, the R group adds to the most substituted carbon. Markovnikov= something is being added to the most substituted carbon Anti-Markovnikov= something is being added to the least substituted carbon

2. When you react an alkene with HBr in CCl4, the Br adds to the ( most, least ) substituted carbon, but when you react an alkene with HBr in ( water, peroxides, chloroform, acetone), the Br adds the least substituted carbon. Briefly explain why this happens. 1.) Peroxides have this generic structure, R-O-O-R. 2.) The O-O single bond is very weak so it will break easily, sending one electron to each oxygen 3.) When that radical is reacted with HBr it will attack the H and the H-Br bond breaks, sending one electron with both, generating the Br radical. 4.) Now that we have the Br radical, lets react it with 1 propene. The Br radical attacks the double bond, as would a Br anion. 5.) Radicals follow the same stability rules as cations, therefore, the radical will form at the 2nd carbon more readily than it will t the 1st carbon. Because of this, the Br will go to the 1st carbon at a higher rate than it will the 2nd, both exist in solution. The addition at the 1st carbon can be referred to as the “major contributor.”

3. Compare and contrast the intermediate and transition states. Transition State: Incomplete bonds, higher energy, cannot be isolated, are represented as the maximas on the energy coordination diagram. Intermediate State: Completed bonds, can be isolated, represented by depressions in the energy coordinate diagram (note: deeper depressions mean that that intermediate can exist for a longer time, so shallow depressions mean that the next step has a lower activation energy.)

4. Provide the missing product(s) for the following six reactions.

5. Fill in the following table Reaction

Reagents

Anti or syn addition?

Markovnikov addition?

Other things to note:

Hydrogenation

syn

NA

Will reduce all carboncarbon bands down to alkanes.

Hydrohalogenations

Roughly equal amounts

Yes

Can rearrange

Hydrohalogenations (in peroxide)

Roughly equal amounts

no

Anti-Markov due to radical addition

Halogenation

Anti

NA

3-member cyclic intermediate

Halohydrin Formation

Anti

-OH = yes -X= no

racemic

Oxymercuration

Anti

Yes

racemic

Hydroboration

Syn

No

racemic

Osmium tetroxide

Syn

NA

Syn addition can happen to either face

Lewis acid in water

Roughly equal amounts

Yes

H+ represents any Lewis acid....