Redraw / Modify

• “Initial Tails” and “Final Heads”
• 3 Ways To Make OH A Better Leaving Group
• A Simple Formula For 7 Important Aldehyde/Ketone Reactions
• Acetoacetic
• 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
• Amines
• 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
• Conformations
• Conjugate Addition
• Curved Arrow Refresher
• Curved Arrows
• Decarboxylation
• 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
• Enolates
• Epoxides – Basic and Acidic
• Evaluating Resonance Forms
• Figuring Out The Fischer
• Find That Which Is Hidden
• Formal Charge
• Frost Circles
• Gabriel Synthesis
• Grignards
• 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
• Hybridization Shortcut
• Hydroboration
• 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
• Paped
• 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
• Rearrangements
• 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
• Stereochemistry
• Strong Acid Strong Base
• Strong And Weak Oxidants
• Strong and Weak Reductants
• Stronger Donor Wins
• Substitution
• 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
• t-butyl
• Tautomerism
• The 4 Actors In Every Acid-Base Reaction
  • Conjugation
• 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

It’s a shame to see smart students lose points on an exam when they actually know the answer.

There’s an easily preventable mistake I often see students making when drawing answers to mechanism problems.

Today I’ll talk about a technique that can help you avoid making simple mistakes.Freelance Teacher Steven calls it the “Redraw and Modify” technique.

I just call it “Draw the Ugly Version First”.

Here’s the bottom line. Once you figure out where the arrows go…. ONLY do the things which the arrows tell you to do.

It sounds easy, but is surprisingly hard!  But every arrow, once drawn (and drawn properly), gives specific instructions about the bonds that form, the bonds that break, and how the charges change.

Some students make the changes that the arrows tell them to do, and they say that they just don’t “feel” right. Unfortunately, feelings don’t come into this. Arrows are dictatorial!

One type of reaction I find students have a hard time with is reactions that form or break rings. This spooks them. So let’s use this as a perfect  occasion to bust out “Redraw and Modify”.

Let’s take a look. Here, we’re adding NaOH to a ketone. This deprotonates one of the alpha carbons, forming an enolate. Next, the enolate is going to attack that carbon several bonds away.

Let’s number the carbons and draw the arrows first (I don’t care if the numbering isn’t IUPAC-approved or anything… it’s just to keep track of each individual atom).

Then, redraw the starting material on the other side of the reaction arrow, complete with curved arrows. We’re going to use the arrows to help us draw the product.
Look at arrow A. What’s it telling us to do?

• Form a bond between C7 and C2
• The charge on C7 will become more positive by 1 (from -1 to zero)

Now draw a line between C7 and C2. It doesn’t have to look nice. It’s just to show you that these are connected.

Let’s look at Arrow B.

Arrow B shows the tail at the C-O Pi bond, and the pair of electrons moving to the oxygen. So what it’s telling us to do is…

• Break the pi bond between C and O
• the charge on the O will become more negative by one (from zero to -1)

Now that we’ve formed and broken the bonds, we can make it look pretty. Count the atoms – we’ve formed a six-membered ring. So draw a hexagon. Then – slowly – atom by atom, “translate” your ugly drawing into the pretty drawing.

I like this becauase it’s methodical. If you follow the method, you’ll get the results. It helps to avoid errors from drawing products improperly, which can sometimes account for ~20% of the lost points on exams. It could easily make the difference between a B and an A.
Thanks for reading! James