Exam I

Question 1

What is an X group? Give 3 examples.

Answer 1

X groups are pi donating. Examples include OMe, OR, and Cl-.

Question 2

What is a Z group? Give 3 examples.

Answer 2

Z groups are pi withdrawing. Examples include ketones, nitro groups, and nitrile groups

Question 3

The best dienes are locked into what conformation?

Answer 3

The best dienes are in a cis conformation.

Question 4

During a Diels Alder reaction, the ____ product is preferred.

Answer 4

During a Diels Alder reaction, the endo product is preferred.

Question 5

For a Diels Alder reaction, the endo product is ___, and the exo product is ____.

Answer 5

Endo=kinetic, exo= thermodynamic.

Question 6

During H-X addition to dienes, you can do _ , _ addition, and _ , _ addition

Answer 6

You can do 1,2 addition, and 1,4 addition to the diene during H-X addition.

Question 7

Diels Alder Reactions can be expedited when you have a __ sub dienophile, and a __ sub diene.

Answer 7

Z (pi withdrawing) dienophile, and an X(pi donating) diene.

Question 8

Xylene:

Answer 8

two methyls on a benzene

Question 9

Phenyl

Answer 9

benzene substituent

Question 10

benzyl

Answer 10

phenyl with a CH2 as well

Question 11

Rules for Aromaticity: (3)

Answer 11

Continuous cyclic array of p orbitals, planar, and 4n+2 electrons

Question 12

Rules for Anti-Aromaticity

Answer 12

Same as for Aromaticity, except you have 4n electrons.

Question 13

Aromatic Heterocycles: Pyridine

Answer 13

Benzene with a nitrogen with lone pair.

Question 14

Aromatic Heterocycles: Pyrrole

Answer 14

5 membered ring with 2 double bonds and a nitrogen with a lone pair.

Question 15

Aromatic Heterocycles: Furan

Answer 15

5 membered ring with 2 double bonds and an oxygen with 2 lone pairs, one of which is in a conjugated pi system.

Question 16

The following are bad arenes for FC alkylation

Answer 16

Z sub arenes, and amino arenes.

Question 17

Halides ( direction, and activation)

Answer 17

Halides are ortho/para directing, and deactivating.

Question 18

Phenols in the presence of water…

Answer 18

lose an H

Question 19

Explain how electron withdrawing groups deactivate rings from reacting with electrophiles.

Answer 19

Electron withdrawing groups create more positive partial charge around the ring, making it hard for a positive electrophile to attach.

Question 20

Explain how electron donating groups activate rings when reacting with electrophiles.

Answer 20

Electron donating groups create more negative partial charge around the ring, making it easier for the positive electrophile to attach.

Question 21

Why is it hard for aryl and vinyl halides to undergo substitution?

Answer 21

They have very unstable carbocations due to bad hybridization shapes.

Question 22

What is aniline?

Answer 22

Benzene with an NH2 group

Question 23

What factors can increase reactivity during SnAr?

Answer 23

more electron withdrawing groups , and more electronegative leaving groups.

Question 24

L Type Ligand

Answer 24

neutral donor

Question 25

X Type Ligand

Answer 25

anionic ligand

Question 26

What are some special types of ligands?

Answer 26

Alkenes, pi allyl, aromatics

Question 27

Oxidation State of a Metal:

Answer 27

of X type ligands + charge on the complex

Question 28

D electron count

Answer 28

[# valence electrons (group#)]-oxidation state

Question 29

Total electron count

Answer 29

D electrons + electrons from ligands

Question 30

What are the steps in a Heck catalytic cycle?

Answer 30

Creation of active metal species, oxidative addition, ligand insertion, B hydride elimination, ligand dissociation, ligand association… etc. combos

Question 31

Which conformation does the Heck reaction’s migratory insertion desire?

Answer 31

The trans conformation of the alkene.

Question 32

Colors: Many conjugated pi systems=

Answer 32

blue or green colors!