Organic Chemistry Flashcards
Carboxylic acid
Prefix: carboxy-
Suffix: -oic acid
Anhydrides
Prefix: alkanoyloxy- and carbonyl-
Suffix: anhydride
Esters
Prefix: alkoxycarbonyl-
Suffix: -oate
Amides
Prefix: carbomoyl-
Suffix: -amide
Aldehydes
Prefix: oxo-
Suffix: -al
Ketones
Prefix: oxo- or keto-
Suffix: -one
Alcohols
Prefix: hydroxy-
Suffix: -ol
Single bond order
Bond type: σ
Hybridization: sp^3
Angles: 109.5
Example: C-C
Double bond order
Bond type: σ and π
Hybridization: sp^2
Angles: 120
Example: C=C
Triple bond order
Bond type: σ and 2π
Hybridization: sp
Angles: 180
Example: C≡C
Flow chart of isomers
- Same connectivity?
Yes - stereoisomers
No - structural - Require bond breaking to interconvert?
Yes - configurational (optical)
No - conformational - Nonsuperimposable mirror images?
Yes - enantiomers (non-superimposable mirror images; have opposite stereochemistry at every chiral C, same chemical and physical properties except for rotation of plane-polarized light and reactions in a chiral environment)
No - diastereomers (non-mirror-image stereoisomers; differ at some, but not all, chiral centers; different chemical/physical properties
Conformational isomers
Differ by rotation around a single sigma bond
- Staggered conformations have groups 60 apart; anti = largest groups are 180 and gauche = 60 apart
- Eclipsed conformations have groups directly in front of each other; totally eclipsed = largest groups are directly in front of each other; strain is maximized
SN1
- 2 steps
- Favored in polar protic solvents
- 3 > 2 > 1 > methyl
- Rate = k[RL]
- Racemic products
- Strong nucleophile not required
SN2
- 1 step
- Favored in polar aprotic solvents
- Methyl > 1 > 2 > 3
- Rate = k[Nu][RL]
- Optically active and inverted products
- Favored with strong nucleophile
Nucleophile
= “nucleus-loving”; tend to have lone pairs or π bonds that can form new bonds to electrophiles. Nucleophilicity is increased by increasing electron density
Nucleophilicity is determined by four major factors
- Charge: nucleophilicity increases with increasing e density (more negative charge)
- Electronegativity: nucleophilicity decreases as electronegativity increases because these atoms are less likely to share e density
- Steric hindrance: bulkier molecules are less nucleophilic
- Solvent: protic solvents can inhibit nucleophilicity by protonating the nucleophile or through H-bonding
In aprotic solvents:
F- > Cl- > Br- > I-
- Opposite in protic
Electrophile
= “electron-loving”; tend to have a positive charge or positively polarized atom that accepts an e pair from a nucleophile; electrophilicity is increased by increasing the positive charge
Most common: carbonyl carbons, substrate carbon in an alkane, carbocations
Leaving groups
Molecular fragments that retain the e after heterolysis (breaking a bond, with both e being given to one of the two products); the best LG will be able to stabilize extra e
Most common: weak bases, large groups with resonance, and large groups with e-withdrawing atoms
Cyclic strain
Angle strain: stretch or compress angles from normal size
Torsional strain: from eclipsing conformations
Nonbonded strain: from interactions wth substituents on nonadjacent carbons ; in cyclohexane, the largest substituent usually takes equatorial position to reduce nonbonded strain
Absolute configuration
An alkene is (Z) if the highest-priority substituents are on the same side of the double bond, and (E) if on opposite sides
- A stereocenter’s configuration is determined by putting the lowest-priority group in the back and drawing a circle from group 1 to 2 to 3 in descending priority
- If this circle is clockwise = R, counterclockweise = S
Alcohols
- Higher B.P. than alkanes due to H-bonding
- Weakly acidic hydroxyl hydrogen
Synthesis: - Addition of water to double bonds
- SN1 and SN2 rxns
- Reduction of carboxylic acids, aldehydes, ketones, and esters
- Aldehydes and ketones with NaBH4 or LiAlH4
- Esters and carboxylic acids with LiAlH4
Organic oxidation-reduction
Level 0: (no bonds to heteroatom): alkanes
Level 1: alcohols, alkyl halides, amines
Level 2: aldehydes, ketones, imines
Level 3: carboxylic acids, anhydrides, esters, amides
Level 4: (four bonds to heteroatom): carbon dioxide
Oxidation
Loss of electrons, fewer bonds to hydrogens, more bonds to heteroatoms (O, N, halogens)