- “Initial Tails” and “Final Heads”
- 3 Ways To Make OH A Better Leaving Group
- A Simple Formula For 7 Important Aldehyde/Ketone Reactions
- Acids (Again!)
- Activating and Deactivating
- Actors In Every Acid Base Reaction
- Addition – Elimination
- Addition Pattern 1 – Carbocations
- Addition pattern 2 – 3 membered rings
- Addition Reactions
- Aldehydes And Ketones – Addition
- Alkene Pattern #3 – The “Concerted” Pathway
- Alkyl Rearrangements
- Alkynes – 3 Patterns
- Alkynes: Deprotonation and SN2
- Aromaticity: Lone Pairs
- Avoid These Resonance Mistakes
- Best Way To Form Amines
- Bulky Bases
- Carbocation Stability
- Carbocation Stability Revisited
- Carboxylic Acids are Acids
- Chair Flips
- Cis and Trans
- Conjugate Addition
- Curved Arrow Refresher
- Curved Arrows
- Determining Aromaticity
- Diels Alder Reaction – 1
- Dipoles: Polar vs. Covalent Bonding
- E2 Reactions
- Electronegativity Is Greed For Electrons
- Electrophilic Aromatic Substitution – Directing Groups
- Elimination Reactions
- Enantiocats and Diastereocats
- Epoxides – Basic and Acidic
- Evaluating Resonance Forms
- Figuring Out The Fischer
- Find That Which Is Hidden
- Formal Charge
- Frost Circles
- Gabriel Synthesis
- Hofmann Elimination
- How Acidity and Basicity Are Related
- How Are These Molecules Related?
- How Stereochemistry matters
- How To Stabilize Negative Charge
- How To Tell Enantiomers From Diastereomers
- Hybridization Shortcut
- Imines and Enamines
- Importance of Stereochemistry
- Intermolecular Forces
- Intro to Resonance
- Ketones on Acid
- Kinetic Thermodynamic
- Making Alcohols Into Good Leaving Groups
- Markovnikov’s rule
- Mechanisms Like Chords
- Mish Mashamine
- More On The E2
- Newman Projections
- Nucleophiles & Electrophiles
- Nucleophilic Aromatic Substitution
- Nucleophilic Aromatic Substitution 2
- Order of Operations!
- Oxidation And Reduction
- Oxidative Cleavage
- Pi Donation
- Pointers on Free Radical Reactions
- Protecting Groups
- Protecting Groups
- Proton Transfer
- Putting it together (1)
- Putting it together (2)
- Putting it together (3)
- Putting the Newman into ACTION
- Reaction Maps
- Recognizing Endo and Exo
- Redraw / Modify
- Robinson Annulation
- Robinson Annulation Mech
- Sigma and Pi Bonding
- SN1 vs SN2
- sn1/sn2 – Putting It Together
- sn1/sn2/e1/e2 – Exceptions
- sn1/sn2/e1/e2 – Nucleophile
- sn1/sn2/e1/e2 – Solvent
- sn1/sn2/e1/e2 – Substrate
- sn1/sn2/e1/e2 – Temperature
- Strong Acid Strong Base
- Strong And Weak Oxidants
- Strong and Weak Reductants
- Stronger Donor Wins
- Sugars (2)
- Synthesis (1) – “What’s Different?”
- Synthesis (2) – What Reactions?
- Synthesis (3) – Figuring Out The Order
- Synthesis Part 1
- Synthesis Study Buddy
- Synthesis: Walkthrough of A Sample Problem
- Synthesis: Working Backwards
- The 4 Actors In Every Acid-Base Reaction
- The Claisen Condensation
- The E1 Reaction
- The Inflection Point
- The Meso Trap
- The Michael Reaction
- The Nucleophile Adds Twice (to the ester)
- The One-Sentence Summary Of Chemistry
- The Second Most Important Carbonyl Mechanism
- The Single Swap Rule
- The SN1 Reaction
- The SN2 Reaction
- The Wittig Reaction
- Three Exam Tips
- Tips On Building Molecular Orbitals
- Top 10 Skills
- Try The Acid-Base Reaction First
- Two Key Reactions of Enolates
- What makes a good leaving group?
- What Makes A Good Nucleophile?
- What to expect in Org 2
- Work Backwards
- Zaitsev’s Rule
Organic chemistry is primarily going to be about moving around electrons. I often say that electrons are to chemistry what currency is to economics.
In order to understand how electrons move around, we first need to know where they are.
Electrons “live” in 3-dimensional areas of space called “orbitals”. The exact shapes and energies are determined by an equation called the Schroedinger equation, but you can kind of imagine them like seats on an Indian bus.
For the purposes of organic chemistry, we’re only going to care about two types of orbitals. S orbitals and p orbitals.
S orbitals look like spheres.
p orbitals look like dumbbells (There’s an area with zero electron density in the middle. That’s called a “node”).
Every atom has three p orbitals, which are oriented at 90 degrees to each other.
So boron, carbon, nitrogen, oxygen, etc. each have one s and three p orbitals (4 total)
One question: how do we jive this with the 4 identical C-H bonds we see at 109 degrees for methane?
One common approach is called “hybridization” . It’s a bit of a kludge, but it gets us where we need to go.
- We’re going to take the s orbital and mix it together with a certain number of p orbitals (1, 2, or 3). The total number of orbitals (s + p) will give us the total number of hybrid orbitals.
- All the hybrid orbitals will be identical, and will orient themselves the maximum distance apart (tetrahedral in the case of CH4).
- Any p orbitals that aren’t part of the hybrid will be “left over” as unhybridized p orbitals.
Still confused? Think of this analogy.
Imagine that you have one 2 L bottle of Sprite and three 2 L bottles of Pepsi. So 4 bottles total. Imagine we pour all the Sprite and Pepsi out, mix them together, and then re-fill the bottles. We’d now have 4 identical bottles of pop that have 25% Sprite character and 75% Pepsi character. (sp3).
Alternatively we could just mix two of the Pepsi bottles with the Sprite, which would give us 3 bottles with 33% Sprite character and 66% Pepsi character (sp2), leaving behind one “unhybridized” Pepsi (p).
Or if we hybridized just one Pepsi, we’d have two bottles with 50% Sprite and 50% Pepi character (sp), and TWO unhybridized Pepsis left over (p).
The table (below) has some examples.
Thanks for reading! James