Chad's Prep Organic Chemistry Module's 1-5

Sp Hybridization has how many electron domains? What is its bond angle? and what is its geometry?

2 Electron Domains, 180 degrees, and linear geometry

Sp2 Hybridization has how many electron domains? What is its bond angle? and what is its geometry?

3 Electron Domains, 120 degrees, and Trigonal Planar geometry

Sp3 Hybridization has how many electron domains? What is its bond angle? and what is its geometry?

4 Electron Domains, 109.5 degrees, and Tetrahedral geometry

a single bond has how many sigma and pi bonds? Is a single bond a weak or strong bond?

1 sigma, 0 pi, weakest bond

A double bond has how many sigma and pi bonds?

1 sigma, 1 pi

A triple bond has how many sigma and pi bonds? Is a triple bond a weak or strong bond?

1 sigma, 2 pi, strongest bond (can increase the boiling point of an organic molecule)

Electrons move toward ____ formal charge and/or away from _____ formal charge

toward + (cation) and away from - (anion)

carbocations are stable in tertiary, secondary, or primary?

Tertiary

Anions are stable in tertiary, secondary, or primary?

Primary

how do you stabilize a negative charge (basicity)?

1. the lesser the charge the more stable the anion
2. the more electronegative the more stable the anion
3. the bigger the atom size the more stable the anion
4. the more resonance the more stable to anion
5. sp is the most stable
6. in aromaticity the more pi (double bonds) the more stable

free radicals

chemical particles with an odd number of electrons which are most stable when they're in tertiary structure and have resonance

which newman projection is most stable?

anti staggered

eclipsed newman projection

-unfavorable
-steric hindrance
-less stable
-higher energy

gauche staggered

two largest groups are 60 degrees apart

cycloalkanes ring strain

-cycloalkanes with fewer than 6 carbons or more than 6 carbons experience ring strain...cyclohexane experiences NO ring strain bc it is able to form the chair conformation and every Carbon is able to form perfect 109.5* angles...however, the further you are away from the perfect 6, the more strain is experienced
-ALSO, cyclodecanes and larger do NOT experience ring strain

What is the Chair conformation stability? Where would dashes and wedges go?

equatorial position is favored, has lower energy and less steric hindrance. Dash means down and wedge means up

Fischer projection dashes and wedges

wedges are horizontal and dashes are verticle

The lower the pKa, the ____ the acid

stronger acid

The lower a pKb, the ______ the base

stronger base

the stronger the acid, the _____ the conjugate base

weaker the conjugate base

the stable the acid, the _____ the base

weaker the base

How do we rank acids and bases?

CARDIO

Charge: More negatively charged species are typically more basic. (more positively charged species are typically more acidic.)

Atom: The larger and/or more electronegative the atom with a negative charge, the more stable it is.

Resonance: stabilization

Dipole Induction: Electron withdrawing groups (electroneg atoms) near the atom that has the negative charge stabilize the ion/molecule

Orbitals: sp> sp2> sp3

pka ranking

if an acid is 3 then what is its conjugate base?

Since the pH adds up to 14 we can say 14-3 = 11 so the ph of the conjugate base is 11

bases get stronger as you go ___ and to the ____ of the periodic table

up (smaller atom size) and to the left (less electronegative) of the periodic table

What is substitution reaction?

Reaction in which one atom (or group of atoms) replaces another atom (or group) within a molecule

What is elimination reaction?

is a reaction in which atoms are removed from an organic molecule to form a double/triple bond. For elimination of alcohols, a strong acid is required (H2SO4) and for elimination of haloalkanes, a strong base is required such as (NaOCH2CH3).

What is addition reaction?

when double bond in converted into single

What is a Diels-Alder Reaction (pericyclic reaction)?

Cycloaddition: reaction between alkene an diene to produce a cyclohexene system.

What are nucleophiles

Electron-rich species that are attracted to a positively polarized atom (i.e. a carbonyl carbon) Most strong nucleophiles have a negative charge while most have a lone pair of electrons at the very least.

Nucleophile strength in aprotic solvents?

Nucleophile in protic solvents?

What are polar aprotic solvents?

Polar aprotic solvents are polar solvents that lack acidic protons and are unable to form hydrogen bonds. They do not have hydrogen atoms that are directly connected to electronegative atoms like oxygen, nitrogen, or fluorine. Because of this, they cannot act as proton donors in hydrogen bonding, but they can still accept protons.

What are some examples of a polar aprotic solvent?

DMSO, acetone, DMF, acetonitrile, ethers (diethyl ether, THF)

what are common electrophiles?

Alkyl halides, carbonyl groups, and carbocations

Electrophiles are

electron pair acceptors

nucleophiles are

electron pair donors (electron rich)

what are some common nucleophiles?

-the hydroxide ion -:OH
-ammonia :NH3
-the cyanide ion -:CN

Carbocation stability

tertiary > secondary > primary > methyl

Radical stability become more stable when they are more substituted

What is the free radical initiation step?

Initiation consists of a covalent bond breaking to form two radicals. Homolytic cleavage is the
rate limiting step of the reaction. The step is endothermic and requires the addition of heat or
light.

What is the free radical propagation step?

Propagation consists of one radical reacting with a stable molecule to generate another radical.

Whats is the free radical termination step?

Termination consists of two radicals reacting to form a stable molecule.

Carbanion stability

methyl > primary > secondary > tertiary

What are some electron withdrawing groups?

What are some electron donating groups?

Prefixes

1-mono
2-di
3-tri
4-tetra
5-penta
6-hexa
7-hepta
8-octa
9-nona
10-deca
11- undec
12- dodec

Rules for naming alkanes

1. Find longest carbon chain (principal chain)
2) Number the PC (first branchpoint has lowest number)
3) Name substituents ("ane" suffix to "yl") then number/alphabetize them (ignore "di,tri..." and hyphenated "tert-, sec-" prefixes but NOT iso and cyclo)

Rules for naming complex substituents

-pick longest carbon chain within substituent (if multiple ways to get the longest then choose the one with the most substituents)
-# of carbons = first word
-side groups of substituent = second word
-Number side groups of substituent (number comes first)
-List substituents in alphabetical order
(There should not be a space between the substituents and the name of the longest chain)

What are some common complex substituents

How do you name the bridged and fused bicyclic compounds?

1. Name the substituents before the parent chain just like other alkanes
2. start the name of the parent chain with the bicyclo- prefix
3. list the number of carbon atoms between bridgehead in each path. List the three numbers in brackets from the highest to lowest separated by periods.
4. End the name of the parent chain with the alkane name that corresponds to all carbon atoms in the ring system including the bridgehead carbon atoms.
5. Number the parent chain beginning with one of the bridgehead carbons as 1
Number the path between bridgehead carbons with the most carbons 1st then continue through th e2nd bridgehead carbon and number the path with the 2nd most carbons. continue numbering the last remaining path with the fewest carbons.

How to name the spiro bicyclic compounds?

1. name substituents before the parent chain just as with other alkanes.
2. start name of parent chain with spiro- prefix
3. list number of carbon atoms in each ring except spiro carbon. list these two in brackets from lower to higher separated by a period.
4. end the name of the parent chain with the alkane name that corresponds to all carbon atoms in the ring system including the spiro carbon atom.
5. number the parent chain beginning with one of the carbons in the smaller ring adjacent to the spirocarbon as #1

What is the order of polarity?

(least polar means extraction will stay in organic layer) Ether < Ester < Ketone < Aldehyde < Amine < Alcohol < carboxyl acid (most polar and since water is polar this will be able to extract into the aqueous layer)

In order to dissolve in ether (organic/ ether layer) should it be most polar or most nonpolar?

Most nonpolar

In order to dissolve in water (aqueous layer) should it be most polar or most nonpolar?

Most polar

How can we extract into aqueous layer with aqueous HCL?

With amines because amines are protonated by HCL and therefore the conjugate acids are more soluble in water.

How can we dissolve into aqueous later with aqueous NaHcCO3?

With carboxylic acid because its deprotonated by NaHCO3 therefore the conjugate base will be more soluble

How can we extract into aqueous layer with aqueous NaOH?

There's more than one answer here because Carboxylic acid and phenols are deprotonated by NaOH so their conjugate bases are more soluble in water (because its charged)

In distillation the compound with what kind of boiling point will evaporate off first?

Compound with the lowest boiling point

the separation of gas chromatography is due to

the difference in boiling point (polarity as well). The compound with the lowest boiling point will elute first. The areas under peaks give relative abundaces

In TLC what has the strongest attraction to the plate? what does it mean?

the most polar compound = travel the least = smallest Rf value. Separation is due to a difference in polarity, more polar solutes have a lower Rf value, less polar solutes have a higher Rf value, and polar solvents increase Rf values.

Column Chromatography

Separation is due to a difference in polarity, a mixture of liquids is filtered through a column of polar beads, and more polar compounds have longer retention times.

Recrystalization occurs when what happens?

the solvent is in high solubility at high temp and low solubility at low tem. purification (separation) due to a difference in solubility. Solute has a higher solubility at high temps but lower solubility at low temps.

What is the priority of functional groups?

Carboxylic acid > anhydride > Ester > Acyl Halide> Amide > Nitrile > Aldehyde > Ketone > Alcohol > Thiol > Amine > alkene or alkyne > alkane (Ether, Sulfide, and Alkyl Halide)

Carboxylic Acid Nomenclature

Suffix (Parent Chain): -oic acid
Prefix (Substituent): Carboxy-

Acid anhydride Nomenclature

Suffix (Parent Chain): -oic anhydride
Prefix (Substituent): alkanoyloxy-

Ester Nomenclature

Suffix (Parent Chain): -oate
Prefix (Substituent): alkoxycarbonyl-

Acyl Halide Nomenclature

Suffix (Parent Chain): -oyl halide
Prefix (Substituent): halocarbonyl-

Amide Nomenclature

Suffix (Parent Chain): -amide
Prefix (Substituent): carbamoyl-

Nitrile Nomenclature

Suffix (Parent Chain): -nitrile
Prefix (Substituent): cyano-

Aldehyde Nomenclature

Suffix (Parent Chain): -al
Prefix (Substituent): formyl-

Ketone Nomenclature

Suffix (Parent Chain): -one
Prefix (Substituent): oxo-

Alcohol Nomenclature

Suffix (Parent Chain): -ol
Prefix (Substituent): hydroxy-

Thiol Nomenclature

Suffix (Parent Chain): -thiol
Prefix (Substituent): -mercapto

Amine Nomenclature

Suffix (Parent Chain): -amine
Prefix (Substituent): amino-

Alkene Nomenclature

Suffix (Parent Chain): -ene

Alkyne Nomenclature

Suffix (Parent Chain): -yne

Ether Nomenclature

Prefix (Substituent): Alkoxy-

Sulfide Nomenclature

Prefix (Substituent): Alkylthio-

Alkyl Haline

Prefix (Substituent): Halo-

Isomers are

compounds with the same molecular formula but different structures and properties. There are two kinds, constitutional isomers and stereoisomers

Constitutional Isomers

compounds with the same molecular formula but different connections among their atoms

Stereoisomers

Compounds with the same structural formula but with a different arrangement of the atoms in space.

cis-trans isomers (geometric isomers)

stereoisomers that differ only with respect to their cis or trans arrangement on a ring or double bond

Isomers with chiral centers

Enantiomers and Diastereomers

Enantiomers

molecules that are mirror images of each other. Have the many of the same physical properties (BP, MP, Polarity, etc)

Diastereomers

stereoisomers that are not mirror images (non-superimposable and non-identical). They have different physical properties (BP, MP, Polarity, etc.)

chiral center

- 4 different group attach to the central carbon
- lack a plane of symmetry
- not superimposable
-Optically active (rotate plane polarized light)

Achiral center

compounds are superimposable (identical) with their images and are optically inactive as they do not rotate plane-polarized light

Meso compound

-optically inactive
-have plane of symmetry
-are achiral but have multiple chiral centers

R and S configuration

R - Right handed configuration
S - Left handed configuration

R and S configuration steps

1. assign priority
2. draw circle from 1 -> 3
3. ensure lowest priority points back, if not invert R/S
R = clockwise circle
S = counterclockwise circle

max possible stereoisomers

2^n; n=number of stereocenters

ranking intermolecular forces strongest to weakest

ion-dipole > hydrogen bonding > dipole-dipole > dispersion

Effects of branching on melting points and boiling points

Branching (usually) decreases the boiling point but increases the melting point

Ranking boiling points

1. Network covalent
2. Ionic
3. Hydrogen Bonding
4. Dipole-dipole
5. London Dispersion

The longer the chain the

higher melting point and boiling point

In solubility

like dissolve like

How so impurities affect the melting point?

It lowers it and broadens the range

Amines are removed by what

HCl