Things to Remember: Organic Chemistry – Flashcards

also 2-propanol

also known as ethyl alcohol

-only thing in common is molecular weight -different atomic connectivity -have different physical and chemical properties -no similarity in structures

-same atomic connectivity (same structural backbone) -differ in how these atoms are arranged in space (wedged vs dashed) -Conformational (rotation around single bonds) vs Configurational (need to break bonds for interconversion)

-the most similar out of all the isomers -rotating around single bond, can cause strain some times -use newman projections -anti-Staggered (lowest energy conformation), gauche, totally eclipsed (highest energy conformation, higher the energy the less stable) Cyclic conformations: -axial H's: perpendicular to plane of the ring(sticking up and down) -equatorial: parallel to the plane of the ring(sticking out) -during a chair flip, axial components become equatorial components and vise versa (however if it was up (wedge) to begin with, it stays up, and down (dash) to begin with stays down) -larger groups need to be in equitorial positions

-can only change from one form to another by breaking bonds -enantiomers and diastereomers (both are optical isomers) -chirality: mirror images cannot be superimposed (carbon with 4 different groups) Enantiomers: non superimposable mirror images of each other, IDENTICAL physical and chemical properties (but they rotate plane-polarized light in opposite directions and react differently in chiral environments) (R and S are opposite between enantiomers) Diastereomers: chiral, same connectivity, NOT mirror images (differ at some chiral centers), non superimposable, need multiple chiral centers obvs DIFFERENT chemical and physical properties, R and S are same between diastereomers) -->meso compounds have chiral centers but also have LINE of SYMMETRY (not optically active) Use R and S to determine absolute configurations E opposite side Z zame side achiral molecules can be superimposed

can be bonding or antibonding depending on the sign of the wave functions. Head to head or tail to tail overlap of atomic orbitals results in a sigma bond (single bond) one pi bond and one sigma bond is a double bond one sigma bond and two pi bonds are a triple bond individually sigma is strong than pi. however double and triple bonds are stronger than single bonds higher the s character, stronger sp3: 109.5 degrees sp2: 120 degrees sp: 180 degrees

Lewis acid: electron pair acceptor (electrophiles) Lewis base: electron pair donor (nucleophiles) Coordinate covalent bond: both electrons in the bond come from the same starting atom

acid is a proton donor, base is a proton acceptor

as bond strength decreases, acidity increases, more electronegative higher acidity

-essentially a lewis base -Nucleophilicity increases with increasing electron density (more negative charge) - The less electronegative the better (more likely to share electron density) -Bulkier the molecule, the less nucleophilic -Protic solvents are bad (can protonate the nucleophile) --> In polar protic solvents, nucleophilicity increases down the periodic table --> In polar aprotic solvents, nucleophilicity increases up the periodic table nucleophile strength is a kinetic property (based on relative rates of reaction), basicity is a thermodynamic property (requires equilibrium) you need polar solvents regardless so that nucleophile can dissolve

-essentially a lewis acid -positively charged (like a Carbonyl carbon) electrophilicity strength is a kinetic property (based on relative rates of reaction), basicity is a thermodynamic property (requires equilibrium)

conjugate bases of strong acids make good leaving groups

1. leaving group leaves --> carbocation 2. nucleophile attacks --> product more substituted the carbocation the more stable (act as electron donors) can form racemic mixtures (carbocation is planar)

1. nucleophile attacks as the leaving group leaves (one step) -concerted reaction -backside attack -less substituted the better (for the nucleophile to attack) - changes absolute configuration

Primary/secondary alcohol to aldehyde/ketone (use PCC) Aldehyde/alcohol/alkane --> caboxylic acid (use KMNO4) alkene --> aldehyde/ketone (use O3 and Ch3SCh3) alkene/alkyne --> carb acid/ketone (use O3 and H2O2) alkene --> epoxide (mCPBA)

aldehyde/ketone --> primary/secondary alcohol (use LAH) amide --> primary amine (use LAH and H+/H2O) carboxylic acid --> primary alcohol (use LAH and H2O) ester --> primary alcohol (use LAH and H2O)

-end in -ol or can have "alcohol" is in the name - Hydroxyl hydrogens in phenols are particularly acidic due to resonance within the phenol ring - two groups on adjacent carbons (ortho), separated by a carbon (meta), opposite side of ring (para) - can do intermolecular hydrogen bonding --> higher melting points and boiling points -Phenols are very acidic -Acidity decreases as more alkyl groups are attached because they are more electron-donating (stabilize positive charges) -Resonance/electron withdrawing groups stabilize alkoxide anions, making alcohols more acidic

Oxidation Reactions: - Primary Alcohol --> (PCC) --> Aldehyde -Secondary Alcohol --> (Na2Cr2O7/H2SO4) --> Ketone -Primary Alcohol --> (CrO3/H2SO4) --> carboxylic acid Tosylates: make hydroxyl groups of alcohols into better leaving groups for nucleophilic substitution reactions

Phenol --> (Na2Cr2O7/H2SO4) --> Ketone

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-Both contain a carbonyl group -Aldehydes are always terminal group - Strong smelling -Aldehydes in -al, ketone end in -one -Dipole moments are strong due to the carbonyl groups, but not as significant of the hydrogen bonding in alcohols - The carbonyl carbon is the most common electrophile

The picture is a hydration reaction Usually the Nu attacks the Carbonyl carbon, the O of the carbonyl grabs an H

Use KMnO4, CrO3/ Ag2O,HxO2 to turn aldehydes into carboxylic acids Use LAH for reduction of ketones

-The acidity of the alpha-H allows many aldehydes/ketones to act as both electrophiles and nucleophiles -The alpha-C is adjacent to the carbonyl carbon, the hydrogens connected to it are called alpha-Hydrogens -Because of the Carbonyl Oxygen and its electron withdrawing effects, it weakens the alphaC-H bond, making the alpha-Carbon easy to deprotonate (help stabilize the carboanion intermediate) -The alpha Hydrogens of ketones tend to be less acidic than those of aldehydes due to electron donating properties of the alkyl group of the ketone, the alkyl groups of the on the ketones make it less likely to interact with nucleophiles and destabilizes the carboanion (increasing steric hindrance)

Because of the acidity of the alpha-Hydrogen, aldehydes and ketones exit in solution as a mixture of 2 isomers: keto and enol form -Enol: presence of a C=C double bond and an alcohol -Keto: the presence of a C=O -Both are tautomers and equilibrium lies on the Keto side When deprotonating the alpha-C using a strong base , and forming the enolate carboanion, it can attack electrophiles in the reactions below When a ketone has two different alkyl groups, 2 forms of an enolate can form (a C=C forming between either the less or more substituted carbon). The Kinetically favored product forms faster but is less stable (double bond to the less substituted carbon). Kinetic product is favored at rapid, irreversible, low temp, strong/sterically hindered base reaction. The Thermodynamically favored product forms slower but is more stable (double bond to the more substituted carbon). Thermodynamic product is favored at slow, reversible, high temp, weak/smaller base reactions.

Carboanion attacks an alpha,beta unsaturated carbonyl compound (double bond).

Enamines are tautomers of imines (C=N). Imines are favored thermodynamically GO OVER

Aldehyde/ketone acts both as electrophile (keto form) and a nucleophile (enol/enolate form) forming a C=C double bond Step 1: forming the aldol (a molecule with both an aldehyde and alcohol) Step 2: dehydration of the aldol, the -OH is removed as water forming an alpha-beta double bond Retro-Aldol Reaction: forming the aldol, but then using a strong base to break the bonds between alpha and beta carbons of a carbonyl (makes to to carbonyl compounds)

- Can act as acids, nucleophiles, and electrophiles, can deprotonate that -OH, have pK around 3-6, excellent at H-bonding and have high boiling points -Always C-1 in a chain, just add "-oic acid" to the end of the name -Good acids since the conjugate base is really stable (resonance)

-Oxidation of aldehydes/primary alcohols using KMnO4

Step 1: Nucleophilic addition Step 2: Elimination of the leaving group (the -OH) and reformation of the carbonyl Pretty much how you form acid derivatives: amines attack to form amides and lactams Esterification: 1. C=O gets protonated, primary alcohol attacks, the -OH of the carboxylic acid takes the H of the alcohol and is the leaving group (water) Anhydrides: Condensation of two carboxylic acids, the -OH of one attacks the Carbonyl carbon of another, add a H+ to create a water on the -OH of the attacked c-acid , water leaves a leaving group

Using Hydride ion or LAH, you can reduce a carboxylic acid into a primary alcohol

Complete loss of carboxyl group as carbon dioxide WATCH VIDEO OVER

long chain carboxylic acids react with sodium or potassium hydroxide, salt is formed Saponification occurs by mixing fatty acids with (sodium or potassium hydroxide) resulting in the formation of a salt that we call soap

More Reactive to Less Reactive: due to amount of electron withdrawing groups Anhydrides ; Esters ; Carboxylic acids ; Amides Steric Hindrance can be used to control where a reaction occurs in a molecule Electronic effects:

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