Basic Organic Compounds

Organic Chemistry §

• study of carbon containing compound
• carbon has great properties for being building block framework
  • can accumulate charge
  • Pauline Electronegativity is intermediate

Alkanes §

• n-alkanes
• cyclic alkanes
• branched-chain

Normal Alkanes §

• also called straight-chain, $n$-alkanes
• all C-H or C-C bonds, fully saturated

• all C are bonded to <2C
  • $C_n{H}_{2n+2}$
• all $C$ are tetrahedral + $s{p}^3$

Cyclic Alkanes §

• cycloalkane: one chain of $C$ attached at ends to form loop

• name: straight chain name + cyclo- at front
• chair conformation:

• boat conformation:

Branched-Chain Alkanes §

• hydrocarbon only containing $C-C$ and $C-H$ single bonds
• 1+ carbon atoms in each molecule is bonded to 3/4 other carbon atoms
• allows for geometrical isomers
  • butane and 2-methylpropane:

• also allows chirality (optical isomerism)
  • one carbon $\to$ 4 different atoms can have mirror images that are not superimposable

• connection to life: gas at gas station has “octane number”
  • branched-chain and cycloalkanes combusts smoothly
  • straight-chain alkanes burn unevenly, create knocking that could damge engine
  • octane number based on this

Nomenclature §

1. named after longest continuous chain
2. group attached to chain is named as -yl vs -ane
3. long chain is named to substituent is the lowest number
4. $>1$ alkyl group of same type use di, tri, etc…
5. several types of alkyl groups, name alphabetically

Rules for Shorthand §

1. all carbons are vertices or points
2. each line is bond
3. assume all $C$ are at octet

Alkenes and Alkynes §

• unsaturated carbon, carbon has double and triple bonds

• alkene: double bond

  • simplest: $C_2{H}_4$, ethene
  • bonding shown below

• 

  • naming: replace -ane in corresponding alkane with -ene
  • can have isomeric forms depending on position of bonding groups

• polyenes: alkenes with multiple double bonds
  • dienes have 2 double bonds, trienes have 3, etc…
  • double bonds lead to cis and trans conformations
  • examples:

• alkyne: triple bond
  • simplest: $C_2{H}_2$, ethyne/acetylene
  • naming: replace -ane in corresponding alkane with -yne
  • bonding shown below

Aromatic Hydrocarbons §

• hexagonal ring of carbon
• simplest example: benzene $C_6{H}_6$

• all bonds (single and double) actually have same length
• 6 $p_z$ orbitals $⟹$ 6 $\pi$ molecular orbitals

Connection to Real Life §

• unsaturated/saturated/cis/trans are also how we described fats (fatty acids)
• saturated and trans unsaturated fats are unhealthy because of compound shape
• strong bonding $⟹$ solid at room temperature, thus clogs arteries

Connection to Human Health (Januvia) §

• Januvia: drug that treats diabetes
• API: Sitagliptin
• unfortunately contained carcinogen from orgo chem reaction used to reduce waste