Analyzing Organic Reactions

Question 1

type of acid or base:
electron acceptor (in formation of a covalent bond), vacant p-orbitals or positively polarized atoms; tend to be electrophiles

Answer 1

Lewis acid

Question 2

type of acid or base: 
electron donor (in formation of a covalent bond), lone pair of electrons that can be donated, are often anions; tend to be nuclephiles

Answer 2

Lewis base

Question 3

created by interaction of Lewis acid and base

Answer 3

coordinate covalent bond

Question 4

type of acid or base:

can donate a proton (H+)

Answer 4

Bronsted-Lowry acid

Question 5

type of acid or base:

can accept a proton (H+)

Answer 5

Bronsted-Lowry base

Question 6

molecule that can act as either a Bronsted-Lowry acid or base (like H2O)

Answer 6

amphoteric

Question 7

measures strength of acid in solution

Answer 7

acid dissociation constant (Ka)

Question 8

acid dissociation constant (Ka)

Answer 8

Ka = [H+] [A-] / [HA]

Question 9

pKa

Answer 9

pKa = -log Ka

Question 10

“nucleus-loving” species; has lone pairs or π bonds that can form new bonds to electrophiles; strength is based on relative rates of reaction with common electrophile

Answer 10

nucleophile

Question 11

four major factors that determine nucleophilicity:

Answer 11

1) charge - nucleophilicity increases with increasing electron density (more negative charge)
2) electronegativity - neucleophilicity decreases as electronegativity increases because these atoms are less likely to share electron density
3) steric hindrance - bulkier molecules are less nucleophilic
4) solvent - protic solvents can hinder nucleophilicty by protonating the nucleophile or though H-bonding

Question 12

“electron-loving” species; has positive charge or positively polarized atom than can accept an electron pair forming new bonds with a nucleophile; more positive compounds are more electrophilic

Answer 12

electrophile

Question 13

a bond is broken and both electrons are given to one of the two products; essentially the opposite of a coordinate covalent polar bond formation

Answer 13

heterolytic reactions

Question 14

molecular fragments that retain electrons after heterolysis; best groups will be able to stabalize extra electrons: weak bases (like I-, Br-, and Cl-) are good, H ions and alkanes are very bad

Answer 14

leaving group

Question 15

a reaction where a nucleophile forms a bond with a substrate carbon and a leaving group leaves

Answer 15

nucleophilic substitution reaction

Question 16

type of nucleophilic substitution reaction:
two steps: first, leaving group leaves forming carbocation, second, nucleophile attacks carbocation from either side; reactions prefer more substituted carbons because alkyl group can donate electron density and stabilize carbocation; rate depends on concentration of substrate

Answer 16

Sn1

Question 17

type of nucleophilic substitution reaction:
one step: nucleophile attacks from back (less sterics) as leaving group leaves; inversion of stereochemistry; reaction prefers less substituted carbons because less steric hindrance; rate depends on concentration of substrate and nucleophile

Answer 17

Sn2

Question 18

hypothetical charge an atom would have if all of its bonds were totally ionic; can be calculated from molecular formula

Answer 18

oxidation state

Question 19

most reduced form of carbon

Answer 19

CH4 : C = -4, each H = +1

Question 20

most oxidized form of carbon

Answer 20

CO2 : C = +4, each O = -2

Question 21

oxidation state of ions

Answer 21

equal to the charge

Question 22

an increase in oxidation state assisted by oxidizing agents

Answer 22

oxidation

Question 23

accept electrons and are reduced in process; have affinity for electrons or unusually high oxidation state, often contain metal and large number of oxygens

Answer 23

oxidizing agents

Question 24

common oxidizing agent(s)

Answer 24

PCC (pyridinium chlorochromate), CrO3 (chromium trioxide), Na2Cr2O7 or K2Cr2O7 (sodium or potassium dichromate)

Question 25

can be oxidized one level to aldehydes (by PCC) or two levels to carboxylic acids (by CrO3, Na2Cr2O7, or K2Cr2O7)

Answer 25

primary alcohols

Question 26

can be oxidized to ketones by most oxidizing agents

Answer 26

secondary alcohols

Question 27

can be oxidized to carboxylic acids by most oxidizing agents

Answer 27

aldehydes

Question 28

a decrease in oxidation state assisted by reducing agents

Answer 28

reduction

Question 29

donate electrons and are oxidized in process; have low electronegativity and ionization energy, often contain metal and large number of hydrides

Answer 29

reducing agents

Question 30

common reducing agent(s)

Answer 30

LAH (LiAlH4, lithium aluminum hydride)

Question 31

can be reduced to alcohols by LAH

Answer 31

aldehydes, ketones, and carboxylic acids

Question 32

can be reduced to amines by LAH

Answer 32

amides

Question 33

can be reduced to a pair of alcohols by LAH

Answer 33

esters

Question 34

the preferential reaction of one functional group in the presence of other functional groups; both nucleophile-electrophile and oxidation-reduction reactions tend to react at the highest priority (most oxidized) functional group

Answer 34

chemoselectivity

Question 35

refers to when bulky groups (such as protecting groups) can make it impossible for the nucleophile to reach the most reactive electrophile, making the nucleophile more likely to attack another region

Answer 35

steric protection

Question 36

Ka

Answer 36

Ka = 10^-pKa