CHEM 241 - Organic Chemistry 2

Why is a benzene ring a functional group?

Because it has 6 pi electrons that work as a single group, not as three individual groups

what process does cyclohexene reaction with bromine (br2)

addition alkene process

why does bromine not react with benzene

because the addition of br2 disrupts the stability of benzene

what are derivatives of benzene called?

substituted benzenes

what is the term used to describe derivatives of benzene

aromatic

what are compounds called when they contain the functional group benzene

arene

what is the parent suffix of an arene compound?

benzene

what is this molecule

hydroxybenzene/phenol

what is this molecule

methylbenzene/toulene

what is this molecule

chlorobenzene

what is this compound?

aminobenzene/aniline

what is this compound?

anisole

what is this compound?

benzaldehyde

What is this compound?

benzoic acid

why do we use common names for functional groups with naming be arene compounds

so we only have to list one substituent - makes the name shorter

what must be done if more than one substituent is present on a benzene

number the substituents

1,2 disubstitution

ortho (o)

1,3 disubstitution

meta (m)

1,4 disubstitution

para (p)

if an amino/functional group is present, what position is it assigned

position 1

ch3

toluene

oh

phenol

och3

anisole

nh2

aniline

no2

nitro

-oic acid

aldehyde

What are the criteria for aromacity

1. the compound must be a ring

2. the compound must have continuously overlapping p-orbitals (all atoms must having the same hybridization)

   1. the ring must contain an odd number of pi electrons

What is the formula for huckel numbers

4n+2
n = number of double bonds

what are the characteristics of an antiaromatic compound

1. it is unstable

2. it is a ring with continuous system of overlapping p orbitals

   1. it has 4n pi electrons

how can we make a nonaromatic compound aromatic

depronate (subtract a hydrogen ion) from the compound

Mass Spec

provides functional group identification + determines mass of molecule

Nitrogen rule

identifying nitriles, amines, amides

nitriles

2 pi bonds

amines

0 pi bonds

amides

1 pi bond + c=o bond

when mass is odd

nitrogen is present

alkyl halides

bromine and chlorine

Index of Hydrogen Deficiency

number of pi bonds in a molecule that contains nitrogen

isotopes of chlorine

cl-35 and cl-37

isotopes of bromine

br-79 and br-81

does this contain chlorine or bromine

chlorine

does this molecule contain chlorine or bromine

bromine

what do differing heights in a mass spec mean

distribution of ions

how are simple ethers named

1. identify organic substituents

   1. add ether to the end

if other functional groups are present, how are ethers considered

alkoxy substituents

what bond angle do ether’s have

120 degrees (tetrahedral)

what is the hybridization of an ether oxygen atom

sp3

why is the boiling point of ethers higher than hydrocarbons

because the oxygen provides a slight dipole moment

what makes peroxides

the combination of ethers and oxygen in the air

are ethers good solvents or solutes

solvents

what type of reaction produces a diethyl ether

sn2

what reagents are used in the williamson ether synthesis

1. ether + (NaH + THF)/Ag2O

2. ch3—I

what type of reaction is williamson synthesis

sn2

what reacts well with Ag2O

sugars

Why do you suppose only symmetrical ethers are prepared by the sulfuric-acid-catalyzed dehydration procedure? What product(s) would you expect if ethanol and 1-propanol were allowed to react together? In what ratio would the products be formed if the two alcohols were of equal reactivity?

A mixture of diethyl ether, dipropyl ether, and ethyl propyl ether is formed in a 1 : 1 : 2 ratio.

What has no impact on ethers?

halogens, nucleophiles, dilute acids, bases

what reaction do ethers always go through

acid cleavage

what two leaving groups are best for ether acid cleavage reactions

HBR and HIwha

what acid does not cleave ethers

HCl

ethers with a benzylic, allylic, or tertiary structure go through what type of reactions

Sn1, E1

ethers with primary or secondary alkyl groups go through what type of reaction

Sn1, Sn2

Why are HI and HBr more effective than HCl in cleaving ethers?

Br⁻ and I⁻ are better nucleophiles than Cl⁻

why is a mixture of products formed when an acid-catalyzed ring is opened?

the ring’s geometrical structure

when the epoxide carbons are secondary and primary, what reaction occurs

sn2

when the epoxide carbons are tertiary and primary, what type of reaction occurs

sn1

what nucleophiles can be used for epoxide opening

amines (RNH2, R2NH) and grigard reagents (RMgX)