Uploaded August 2026 | Updated September 2026, 1 week ago
Fischer Projections are the "straightjackets" or organic chemistry: They force molecules into unstable, eclipsed conformations that make it impossible to see the true zig-zag shape. In this video, I'm showing you my signature "Caterpillar Method" to convert Fischer Projections to Skeletal structures without accidentally flipping your stereocenters.
🍵Buy the Professor a tea to keep the videos coming: patreon.com/c/ChemistryinaNutshell
Most students lose points because they forget the 180° rotation required to move from a flat chain to a zig-zag. I'll show you how to "map" your molecule and use a simple 8-step checklist to ensure your R and S configurations stay exactly where they belong.
In this video, we cover:
• Why Fischer Projections are high-energy "straightjackets."
• The 7 Steps of the Caterpillar Mapping Method.
• The "Head Perspective" trick for placing wedges and dashes.
• The 180° Trap: Why you must flip your groups when you zig-zag.
• Verification: Using R/S as your ultimate exam insurance.
🧬Master R/S assignments in 6 minutes: Watch the "Hand Rotation" method here: youtu.be/OKpYdKI2diY
🥾Need a reaction mechanisms bootcamp? I've got you covered: youtube.com/playlist?list=PLvUW25kBaMMtvqt_IBtezyBX_kk447pxZ
🥽As an Amazon Affiliate, I earn from qualifying purchases at no extra cost to you.
🥼My recommendations: amazon.com/shop/chemnut?ccs_id=11f20bce-5f74-427b-85fb-bdf66849405a
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0:00 Why Fischer Projections are "Straightjackets"
0:20 2,3-Dibromobutane Conformation (Molecular Model)
0:59 Step 1: Rotate 90° Rule
1:14 Step 2: Choose a Perspective
1:41 Step 3: Add Achiral Groups
2:02 Step 4: Assign Left Groups to Wedges or Dashes
2:13 ⚠️TRAP #1: Wedge/Dash Trap
2:37 Step 5: Add Chiral Groups
2:50 Step 6: Convert Backbone to Zig-Zag
2:58 ⚠️TRAP #2: The 180° R/S Flip Trap
4:04 Step 7: Exam Insurance (Check R/S)
4:25 Step 8: Convert to Skeletal Structure
4:43 Challenge: D-Glucose Conversion
Citations:
Paula Yurkanis Bruice, "Organic Chemistry" 8th ed
openstax.org/details/books/organic-chemistry
openstax.org/details/books/chemistry-2e
Music: youtu.be/lL6AsbG07xY
Fischer Projections are the "straightjackets" or organic chemistry: They force molecules into unstable, eclipsed conformations that make it impossible to see the true zig-zag shape. In this video, I'm showing you my signature "Caterpillar Method" to convert Fischer Projections to Skeletal structures without accidentally flipping your stereocenters.
🍵Buy the Professor a tea to keep the videos coming: patreon.com/c/ChemistryinaNutshell
Most students lose points because they forget the 180° rotation required to move from a flat chain to a zig-zag. I'll show you how to "map" your molecule and use a simple 8-step checklist to ensure your R and S configurations stay exactly where they belong.
In this video, we cover:
• Why Fischer Projections are high-energy "straightjackets."
• The 7 Steps of the Caterpillar Mapping Method.
• The "Head Perspective" trick for placing wedges and dashes.
• The 180° Trap: Why you must flip your groups when you zig-zag.
• Verification: Using R/S as your ultimate exam insurance.
🧬Master R/S assignments in 6 minutes: Watch the "Hand Rotation" method here: youtu.be/OKpYdKI2diY
🥾Need a reaction mechanisms bootcamp? I've got you covered: youtube.com/playlist?list=PLvUW25kBaMMtvqt_IBtezyBX_kk447pxZ
🥽As an Amazon Affiliate, I earn from qualifying purchases at no extra cost to you.
🥼My recommendations: amazon.com/shop/chemnut?ccs_id=11f20bce-5f74-427b-85fb-bdf66849405a
🔬Start any shopping journey here: amzn.to/3IXuAcS
0:00 Why Fischer Projections are "Straightjackets"
0:20 2,3-Dibromobutane Conformation (Molecular Model)
0:59 Step 1: Rotate 90° Rule
1:14 Step 2: Choose a Perspective
1:41 Step 3: Add Achiral Groups
2:02 Step 4: Assign Left Groups to Wedges or Dashes
2:13 ⚠️TRAP #1: Wedge/Dash Trap
2:37 Step 5: Add Chiral Groups
2:50 Step 6: Convert Backbone to Zig-Zag
2:58 ⚠️TRAP #2: The 180° R/S Flip Trap
4:04 Step 7: Exam Insurance (Check R/S)
4:25 Step 8: Convert to Skeletal Structure
4:43 Challenge: D-Glucose Conversion
Citations:
Paula Yurkanis Bruice, "Organic Chemistry" 8th ed
openstax.org/details/books/organic-chemistry
openstax.org/details/books/chemistry-2e
Music: youtu.be/lL6AsbG07xY
![The Benzene Puzzle [Part 1]](https://i.ytimg.com/vi/W2BysSrl7Hs/mqdefault.jpg "The Benzene Puzzle [Part 1]
Can you figure out the structure of benzene from the data we had in the 1800s? It certainly eluded early chemists for a long time!
Watch the whole playlist. Can you solve the puzzle before Kekule? https://www.youtube.com/playlist?list=PLvUW25kBaMMvs5nsG1VUQA0wsP9LGEQha
Playlists to ACE Chemistry:
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Time Stamps:
0:00 Introduction
Pre-1865
0:31 Molecular Formula of C6H6 and 4 Degrees of Unsaturation
5:25 Unusual Stability
5:34 No Electrophilic Addition Reactions / No C=C
6:56 Substitution Products / Equivalent Hydrogens
8:02 Ethane & Propane Substitutions & Equivalent Hydrogens
The 1865 Challenge
9:54 Propose a Structure of Benzene Give Information Available in 1865
10:29 Answers from 1865
1865 - 1890
13:15 Kekulés 1865 proposition that 2 different 1,2-disubstituted products are indistinguishable
*** Mistake: Kekulé never used his first given name (Friedrich); he was known throughout his life as August Kekulé.
13:31 Dewar and Ladenburg Structures
Citations:
Organic Chemistry, 8th ed. Bruice, Paula Yurkanis. 2016. Pearson. Chapter 8
#benzene #puzzle #chemistry")
