DAT Organic Chemistry Review

Bond angles Tetrahedral

109.5

Bond angle Trigonal Planar

120

Bond angle strait

180

Lewis Acid

Electron pair acceptor

Lewis Base

Electron Pair donor

Molecular orbital order

Sigma, Sigma star, pi, Sigma 2s, sigma 2s star, Pistar

Acid Chloride

Carbon double bonded to an oxygen, and single bonded to a chloride and an R group

Alcohol

Oxygen with two lone pairs and a hydrogen attached to an R group, hydroxy group

Aldehyde

Carbon double bonded to an Oxygen and to a hydrogen and an R group, Carbonyl group

Alkane

single bonds with Hydrogens

Alkene

compound with double bonds

Alkyl halide

halide bonded to an R group, Halo group

Alkyne

triple bond between carbons

Amide

Carbon double bonded to oxygen and then to a nitrigen bonded with 2 hydrogen or R groups

Amine

R group or groups bonded to a Nitrogen and or hydrogens, Amino group

Anhydride

2 carbons double bonded to 2 oxygen and single bonded to one oxygen with R groups attached on both ends

Aromatic compound

A ring, phenyl group

Carboxylic compound

Carbon double bonded to Oxygen and single bonded to an oxygen with another hydrogen

Ester

Carbon double bonded to Oxygen, and single bonded to another oxygen with an R group attached.

Ether

2 R groups separated by an oxygen, AKA alkoxy group

Ketone

2 R groups separated by a carbon double bonded to an oxygen. AKA carbonyl group

Nitrile

Carbon group triple bonded to Nitrogen and another R group AKA cyano Group

Sulfide

2 R groups separated by a Sulfur, AKA alkylthio group

Thiol

R group attached to a sulfur, which is connected to a hydrogen, AKA mercapto group

Thioester

R group connected to a Carbon double bonded to an Oxygen and another Sulfur with an R group

pka Hbr

-9

pka hcl

-7

pka h3O+

-2

pka Oh2

-2

pka COOH

5

pka nh4+

11

pka R nh3

11

pka h20

16

pka alcohol

16

pka alkyne

25

pka nh3

38

pka R nh2

38

pka alkene

43

pka alkane

50

Constitutional Isomer

Different compound with the same molecular formula. Structural Isomer. Differs in the way that they are connected

Stereoisomer

the same molecular formula, but different orientation in space. Comprises entantiomers and diasteriomers

achiral

superimposable, don't have stereoisomers

chiral

are not superimposable

Stereogenic Center

also known as chiral center, an element bonded to 4 distinct groups.

enantiomer

differs in the 3 dimensional arrangement. Contains chiral centers

Power rule of sterioisomers

2^n n is the number of stereoisomers

Meso Compound

A compound that contains chiral centers yet is superimposable on it's own image. Hint is to look for a plane of symmetry.

Determining Leaving group ability

the better leaving group is the weaker base

trends in basicity of the periodic table

left to right decreases, down the table decreases in basicity

determining strength of a nucleophile

The stronger the base, the more likely the nucleophile.

steric hindrance

large bulky groups prevent the mobility of a nucleophile

Polar Protic solvents

have a charge and connect to polar solutes through a SH or OH bond

Protic Solvents trends in nucleophilicity

increases down the periodic table because larger molecules are less likely to bind to the solvents and are

Aprotic Solvents

follows the rules for nucleophilicity

effect of increasing R number on rate of reaction

as more and more R groups are added, steric hindrance causes reaction rates to decrease because the energy of activation is increased

rate determination in an SN1 reaction

only by changing the concentration of the alkyl Halide is the rate changed

stability of a carbocation

increases as more R groups are attached to the positive charged carbon

aryl halide

halogen bonded to an aromatic ring

alkyl halide

halogen bonded to an sp3 carbon

Vinyl halide

halogen bonded to double bonded carbon

SN1 reaction

a two step process in which the carbocation is formed first through the breaking of bonds with the leaving group, and then a new bond is formed with the nucleophile

SN2 reaction

a one step process in which the reaction is concerted, both the bond breaking with the leaving group and the formation of bond wit nucleophile occur at the same time.

SN1 reaction degree of alkyl halide

3rd and second degree alkyl halides. Has to have some substitution in order hybridize and balance the charge.

SN2 reaction degrees of akyl halides

Steric Hindrance determines the speed. Less substituted goes faster

SN1 reaction nucleophile

wants a weak nucleophile

SN2 reaction nucleophile

wants a high concentration of a strong nucleophile

Ranking of leaving group ability for both SN1 and SN2 reactions

Most basic is best, increasing in basicity down the periodic table

SN1 preffered solvent

aprotic, meaning polar but containing no hydrogen bonds, so as to not dissolve the nucleophile

SN2 preffered Solvent

protic, which contains hydrogen bonds so as to solvate the cations that are formed through the reaction.

solvolysis

Using the solvent, or the solution in which the reaction is taking place, as the nucleophile

Good nucleophiles that are weak bases

Iodine anion, bromine anion, Chlorine anion, fluorine anion, cyanide, SCH3, and N3 anion Azide

leaving group ability

more acidic the better, down the periodic table is better

regioselective

a reaction yields predominantly one constitutional isomer over another when more than one is possible

stereoselective

a reaction yields more of one stereoisomer over another when more than one is possible

SN1, SN2, E1, E2 Chart

Nucleophile considerations when determining type of elimination or substitution

must be a weak nucleophile for a carbocation to form

Ranking of elements for leaving group ability

IBrCl

Dehydration of alcohols

primary carbons undergo E2 because they are so unstable as carbocations, Secondary and tertiary carbons undergo E1

Good nucleophiles good bases

O H negative, R O H negative, R 2 O H negative, Lithium, negatively charged alkyne

Good nucleophiles weak bases

Iodine anion, bromine anion, cyanide anion, Ch3coo, H S minus, R 2 N H, Azide, Sulfur with R group

DBU

weak nucleophile because it is a big molecule, but a good base

DBN

weak nucleophile because it is a big molecule, but a good base

LDA

Weak nucleophile because it is a big molecule, but a good base

rule for bases

weak base if conjugate acid is stronger than 12

HO-

Good nucleophile, Good base

H20

weak nucelophile, weak base

I-

good nucleophile, bad base

RS-

good Nucelophile, weak base

alkyne anion

strong nucleophile, strong base

methyl anion

strong base, strong nucleophile

Lithium cation

strong nucleophile, strong base

ROH

weak Nucleophile, weak base

RCOOH

weak Nucleophile, weak base

RCOO-

weak base, strong nucleophile. PKA carboxylic acid is 5

Azide anion

strong nucleophile, weak base

HS-

strong nucleophile, weak base

R2N-

strong nucleophile, strong base

Cyanide anion

weak base, strong nucleophile

Br-

weak base, strong nucleophile

R2NH

strong nucleophile, weak base