Organic Chemistry Final (255)

I HAVE TO PASS MORE THAN ANYTHING

X > 1.9 (Electronegativity)

Ionic bond

1.9 > X > 0.5 (Electronegativity)

Polar covalent bond

0.5 > X (Electronegativity)

Non-Polar Covalent Bond

Covalent Bond trends

Nonmetal — Nonmetal

Sharing electrons

Ionic Bond trends

Metal — Nonmetal

Transferring electrons

Planar - Bond Angles

90º

Tetrahedral - Bond Angles

109º

Trigonal Pyramidal - Bond Angles

107º

Trigonal Planar - Bond Angles

120º

4 regions of electron density

result in a tetrahedral arrangement with bond angles of 109.5º

3 regions of electron density

result in a trigonal planar arrangement with bond angles of 120º

2 regions of electron density

result in a linear arrangement with bond angles of 180º

H₂O bond angle

is approximately 104.5º due to the two lone pairs on the oxygen atom

CO₂

is a linear molecule with bond angles of 180º between the oxygen atoms

Alkanes

Contain C-H single bonds only

Alkenes

Contain C=C double bonds

Alkynes

Contain H - C=C - H triple bonds

Alcohols

Contain and O-H bond

Ethers

Contain an O connected to two carbons by single bonds

Amines

Contain an NR₃ group (where R is a hydrogen or a carbon substituent)

Aldehydes and Ketones

Contains a C=O double bond (carbonyl group with a hydrogen or carbon substituent)

Carboxylic Acids

Contains a carbonyl group bonded to an OH group

Esters

Contain a carbonyl group bonded to an OR group (where R is a carbon substituent)

Four sigma bonds (single bonded carbon)

sp³ hybridized; 109.5º bond angles

Three sigma bonds and one pi bond (double bonded carbon)

sp² hybridized; 120º bond angles

Two sigma bonds and two pi bonds (triple bonded carbon)

sp hybridized; 180º bond angles

Meth-

1 Carbon atom

Eth-

2 Carbon atoms

Prop-

3 Carbon atoms

But-

4 Carbon atoms

Pent-

5 Carbon atoms

Hex-

6 Carbon atoms

Hept-

7 Carbon atoms

Oct-

8 Carbon atoms

Non-

9 Carbon atoms

Dec-

10 Carbon atoms

Constitutional Isomers

Compounds with the same molecular formula but different structural arrangements of atoms

Procedure for naming alkanes

1. Identify the longest continuous carbon chain and number the carbons to give the lowest possible numbers to the substituents

2. Identify the substituents and assign a number based on the position on the longest linear chain (use the lowest number possible)

Methylethyl common name

Isopropyl

Primary carbon center (1º)

bonded to 1 other carbon atom

Secondary carbon center (2º)

bonded to 2 other carbon atoms

Tertiary carbon center (3º)

bonded to 3 other carbon atoms

Quaternary carbon center (4º)

bonded to 4 other carbon atoms

Lowest energy Newman conformations

Staggered

Highest energy Newman conformations

Eclipsed

How are large substituents arranged on chair configurations

Equatorial

How are small substituents arranged on chair configurations

Axial

Stereoisomers

Same connectivity but different distance configuration

Constitutional isomers

same molecular formula, different connectivity of atoms

Chiral

An object that is not superimposable on its mirror image; i.e. four different groups attached to a carbon atom

Achiral

An object that is superimposable on its mirror image; it has a plane of symmetry; i.e. typically has two identical groups attached to a carbon atom.

R

Clockwise

Clockwise

R

S

Counterclockwise

Counterclockwise

S

Diastereomers

stereoisomers that are not mirror images of each other; different compounds with different physical and chemical properties

Enantiomers

stereoisomers that are mirror images of each other (chiral); have identical physical and chemical properties in an achiral environment

Cis

if two substituents are on the same side of a double bond or ring

Trans

if two substituents are on opposite sides of a double bond or ring

Racemic mix

equal amounts of both enantiomers in a mixture.

Percent optical purity (formula)

(([a] sample)/([a] pure enantiomer)) x 100

Enantiomeric excess (ee)

% R - % S =  % of one enantiomer over the other (vice versa)

0% ee

indicates a racemic mix with equal concentrations of both enantiomers (1:1)

100% ee

indicates a pure single enantiomer with no presence of the other enantiomer

Acids are

proton donors

Bases are

proton acceptors

A conjugate base is formed when

an acid donates a proton

A conjugate acid is formed when

a base accepts a proton

Low pK_a

strong acid

High pK_a

weak acid

Z alkene

two highest priority groups are on the same side

E alkene

two highest priority groups are on opposite sides

Many ___ acids contain C=C double bonds

unsaturated/fatty

Nucleophile

has electrons to give

Electrophile

wants electrons

O-H is

a strong nucleophile

H₂O is

a weak nucleophile