The diversity of organic compounds leads to ...

Organic NomenclatureTrivial (historic) names...

CH3CO2H

CH3OH

HCO2H

HO2CCH2CO2H

Compound names have four fields:

Root Unsaturations Functional GroupSubstituents

Systematic IUPAC Nomenclature:

2

The compound root name is based on the number of carbon atoms in the longest continuous chain or ring.

n1234567891011121314151617181920

CnH2n+2CH4CH3CH3CH3CH2CH3CH3(CH2)2CH3CH3(CH2)3CH3CH3(CH2)4CH3CH3(CH2)5CH3CH3(CH2)6CH3CH3(CH2)7CH3CH3(CH2)8CH3CH3(CH2)9CH3CH3(CH2)10CH3CH3(CH2)11CH3CH3(CH2)12CH3CH3(CH2)13CH3CH3(CH2)14CH3CH3(CH2)15CH3CH3(CH2)16CH3CH3(CH2)17CH3CH3(CH2)18CH3

AlkaneMethaneEthanePropaneButanePentaneHexaneHeptaneOctaneNonaneDecaneUndecaneDodecaneTridecaneTetradecanePentadecaneHexadecaneHeptadecaneOctadecaneNonadecaneEicosane

Cycloalkanes...

3

The presence of multiple bonds is indicated by changing the "a" of the "ane" into "ene" or "yne" in the third field of the name.

H2C CHCH3CH3CH2CH3 HC CCH3

1,3-cyclopentadiene

Where necessary, the position of the unsaturation is numbered…

4

COH

O

CO2H Carboxylic acid -anoic acid

The presence of functional groups is indicated using the suffixes of Table 1.1Functional groups are given the smallest possible number of the longest chain.

H3CC

OH

O

CH3CH3

N

H

H

Amine -amineNH2

NH2

NH2

5

H3CH2CC

CH2CH3

O

H3CC

CH2CH2CH3

O

H C CH2CH2CH2CH3

O

pentan-3-one

pentan-2-one

pentanal

HC

O

H

CH2CH3

H pentenal

pent-2-enal

trans-pent-2-enal

6

H3C C C CH2 CH2 CH2 OH

123456

Hex-4-yn-1-ol

O

Cyclopent-2-enone

O

Cl5-chlorocyclopent-2-enone

7

SubstituentsStructural elements (sometimes functional groups) that are not part of the longest chain, but attached to it.

• appear first in the name of a compound

• each is numbered with respect to their position.

• where there is a choice of numbering possibilities, that with the smallest first number is used.

• the substituent name is prefixed with an indication of the number of such substituents if more than one is present (di, tri, tetra, penta etc.)

8

• Some common substituents include:

Name Name Name

-CH3 methyl -OCH3 methoxy -F fluoro

-CH2CH3 ethyl -OCH2CH3 ethoxy -Cl chloro

-CH2CH2CH3 propyl -OCH2CH2CH3 propoxy -Br bromo

-CH2CH2CH2CH3 butyl -OCH2CH2CH2CH3 butoxy -I iodo

etc. etc. -NO2 nitro

-CH(CH3)2 isopropyl -OCH(CH3)2 isopropoxy -C6H5 phenyl

-C(CH3)3 t-butyl -OC(CH3)3 t-butoxy -CH2C6H5 benzyl

9

• In summary, to name an organic molecule, work back-to-front:– Find the principal functional group.– Find the longest chain (or ring) including the principal functional group

and all double/triple bonds.– Number the chain starting at whichever end gives the principal functional

group the lower number. (For a ring, start numbering at the principal functional group.)

– Name the principal functional group, numbering if necessary.

– Name the main chain (or ring), numbering the C=C or CC bonds if necessary. If this gives a name in which the next letter after the ‘e’ of ‘ane’, ‘ene’ or ‘yne’ is a vowel, drop the ‘e’.

– Name and number the substituents on the main chain. If a substituent appears more than once, use a prefix to indicate how many there are and include a number for each appearance. List the substituents in alphabetical order (not counting prefixes i.e. trichloro comes before dimethyl because c comes before m) followed by the main chain (or ring) name.

– Finally, add cis- or trans- to the front of the name if necessary.

OBr

Br

CH3O1

23

45

OBr

Br

CH3O

10

CH3CHCH2CHCH2CH2CH3

CH2

CH3

OH

O

OH

O

OH

11

CHO

Br

F Cl

F

Ph

Ph

O

O2N CO2H CF3CH2OH

O

OCH2CH3

12

C

CC

C

CC

H

H

H

H

H

H

Benzene

Molecules with this substructure are treated as a class - the arenes.

CH3 NH2 OH OCH3 CO2H

Toluene Aniline Phenol Anisole Benzoic Acid

13

CH3

Cl

O2N

C(CH3)3

OH

H3CO

Cl

Cl

14

• Esters can be made by reacting a carboxylic acid with an alcohol:

• Their names reflect this. The chain from the alcohol is named as a substituent followed by a space. Then the carboxylic acid is named, changing the suffix from ‘–oic acid’ to ‘–oate’.e.g. The ester above was made from ethanol and benzoic acid.

It is called ethyl benzoate.

• What is the structure of octyl ethanoate?

O

OO

OH OH

OH H+ +

15

• Amides are made by reacting a carboxylic acid with an amine:

• Their names reflect this. The chain from the amine is named as a substituent followed by a space. Then the carboxylic acid is named, changing the suffix from ‘–oic acid’ to ‘–amide’.

e.g. The amide above was made from ethanamine and benzoic acid.

It is called ethyl benzamide.

• What is the structure of propyl hexanamide?

N

O

H

O

OH N

H

HO

H H+ +

16

Organic chemical reactions can be classified into several basic categories:

Proton-transfer reactions (Brønsted acid/base reactions)SubstitutionAddition and EliminationOxidation and Reduction

Proton-transfer reactions...

N + HCl N H + Cl

H3CC

OH

O

+ NaOHH3C

CO

O

Na + H2O

17

Substitution

OH + NaBrH2SO4

Br

Br + NaCN CN

H3CC

Cl

O

+ NH3

H3CC

NH2

O

Br2, FeBr3

Br

18

Elimination Reactions ... the reverse of addition, forms a pi bond.

Br + KOH

H3CH2CC

CH3

H3CO OH

H3CH2CC

CH3

O

+ CH3OH

Addition Reactions ...to a pi bond.

H2CC

CH3

H

Br2

CH2

CCH3

H

Br

Br

H3CC

CH3

O 1) NaCN2) H2SO4

H3CC

CH3

HO CN

19

Oxidation ...the addition of O or removal of H2

CH2OHPCC

C

O

H

KMnO4 C

O

OH

Reductions ...the addition of hydrogen, H2

C

O

HCH2OH C

O

OH

NaBH4, CH3OH

LiAlH4, ethyl ether

Ph

H

H

CO2H H2, Pd/C

Ph

H

H

CO2H

H

H

20

CH3C

CH3

CH3

BrCH3OH C

H3C

CH3

CH3

OCH3

Practice!

O

O

H3COH2C

O

O 1) CH3Li, ethyl ether, 0°C2) H2O

O

HO

H3COH2C

O

O

H3C

H3C

H

H

CH3MCPBA

H3C

H

H

CH3O

21

H3C

H

H

CH3 Br2CH3CHBrCHBrCH3

NO2HNO3, H2SO4

OHPBr3

Br

CN LiAlH4, ethyl ether

CH2NH2

22

Kinetics and Reaction Mechanism

•Reactions take place as a result of collisions between molecules/ions.•These collisions are are called “elementary processes”.•In these processes, bonds are broken and/or formed if the collision is sufficiently energetic (to overcome ∆G‡) and the collision geometry is appropriate. •The overall conversion of reactants to products may involve several elementary processes.

Understanding electron movement is a critical part of understanding chemical reactions.

BrC

CH2

H3C CH3

C

CH3

CH3H3C

H Br

BrC

CH3

CH3H3C

C

CH3

CH3H3C

Br

1)

2)

23

Electrophiles and Nucleophiles - the components of polar reactions.

Nucleophiles are species that seek positiveness. They can be anionic, negatively polarized or electron-rich…

Electrophiles are species that seek negativeness. They can be cations, positively polarized, or electron deficient.

Br

O

H

H

C

CH2

H3C CH3C

O

H3C CH3O

H

C

O

H3C CH3

Br BrO

H

HH C

CH3

CH3H3C

H Br

24

Arrow Pushing...

Organic chemists use arrows to indicate the flow of electrons during reactions. The importance of this formalism cannot be overstated.

Arrows always start at electron pairs (either lone pairs or bonds).

ARROWS NEVER INDICATE THE MOVEMENT OF AN ATOM.

C

O

H NH2 HC

NH2

O

When pushing electrons, remember that period 2 elements (including C, N and O) can NEVER have more than 8 electrons

H2CC

CH2

H

CH2C

H2C

H

C

O

H O HC

O

O

25

N C H S

H

N C H S

H

N C H O

H

HN C H

H

O

H

H O NCH NCH

OH

26

B

F

F FN

CH3

H3C CH3

B N

F

F

F

CH3

CH3

CH3

C

O

HH

B

F

F F C

O

HH

B

FF

F

27

CH2

CH3C CH3

H2C

CH3C CH3

H O

H

H

H

O

H

H O

H

HH O

H

H

H

CH2

CH3C CH3

H Br

CH3

CH3C CH3

Br

H

28

CN

H

C Cl

HH

H

CC

H H

N Cl

H3C

C Br

HH

H

CI

H H

BrI

CN

H3C

C O

H3C

H3C

CC

H3C

ON

29

CH3

CH3C CH3

+Br

H3C

CH3C

CH3

Br

C

O

HH

H

OH

H

H3C

CH3C

CH3

Br CH3

CH3C CH3

+Br

C

O

HH

H

H

OH

H

O

H

C

O

HH

H

C

O

HH

H

H

OH