|Ch. 1 - A Review of General Chemistry||4hrs & 47mins||0% complete|
|Ch. 2 - Molecular Representations||1hr & 12mins||0% complete|
|Ch. 3 - Acids and Bases||2hrs & 45mins||0% complete|
|Ch. 4 - Alkanes and Cycloalkanes||4hrs & 18mins||0% complete|
|Ch. 5 - Chirality||3hrs & 33mins||0% complete|
|Ch. 6 - Thermodynamics and Kinetics||1hr & 19mins||0% complete|
|Ch. 7 - Substitution Reactions||1hr & 46mins||0% complete|
|Ch. 8 - Elimination Reactions||2hrs & 21mins||0% complete|
|Ch. 9 - Alkenes and Alkynes||2hrs & 10mins||0% complete|
|Ch. 10 - Addition Reactions||3hrs & 28mins||0% complete|
|Ch. 11 - Radical Reactions||1hr & 55mins||0% complete|
|Ch. 12 - Alcohols, Ethers, Epoxides and Thiols||2hrs & 42mins||0% complete|
|Ch. 13 - Alcohols and Carbonyl Compounds||2hrs & 14mins||0% complete|
|Ch. 14 - Synthetic Techniques||1hr & 28mins||0% complete|
|Ch. 15 - Analytical Techniques: IR, NMR, Mass Spect||7hrs & 20mins||0% complete|
|Ch. 16 - Conjugated Systems||5hrs & 49mins||0% complete|
|Ch. 17 - Aromaticity||2hrs & 24mins||0% complete|
|Ch. 18 - Reactions of Aromatics: EAS and Beyond||4hrs & 31mins||0% complete|
|Ch. 19 - Aldehydes and Ketones: Nucleophilic Addition||4hrs & 54mins||0% complete|
|Ch. 20 - Carboxylic Acid Derivatives: NAS||2hrs & 3mins||0% complete|
|Ch. 21 - Enolate Chemistry: Reactions at the Alpha-Carbon||1hr & 56mins||0% complete|
|Ch. 22 - Condensation Chemistry||2hrs & 13mins||0% complete|
|Ch. 23 - Amines||1hr & 43mins||0% complete|
|Ch. 24 - Carbohydrates||5hrs & 56mins||0% complete|
|Ch. 25 - Phenols||15mins||0% complete|
|Ch. 26 - Amino Acids, Peptides, and Proteins||2hrs & 54mins||0% complete|
|Ch. 26 - Transition Metals||5hrs & 33mins||0% complete|
|E2 Mechanism||16 mins||0 completed|
|Beta Hydrogen||9 mins||0 completed|
|E2 - Anti-Coplanar Requirement||13 mins||0 completed|
|E2 - Cumulative Practice||8 mins||0 completed|
|E1 Reaction||22 mins||0 completed|
|Solvents||12 mins||0 completed|
|Leaving Groups||7 mins||0 completed|
|Nucleophiles and Basicity||6 mins||0 completed|
|SN1 SN2 E1 E2 Chart (Big Daddy Flowchart)||19 mins||0 completed|
|Cumulative Substitution/Elimination||29 mins||0 completed|
|E2 - Anti-Coplanar Requiring Rotation|
|Rate Calculations of Competitive Mechanisms|
|Neighboring Group Participation|
|Intramolecular Substitution/Elimination Practice|
|The E1cb Mechanism|
In order to predict E2 products, we’ll have to get good at recognizing how many different and eligible β-hydrogens exist.
Elimination reactions remove β-hydrogens to create double bonds.
Concept #1: The number of unique β-carbons helps predict the number of possible products.
Now I want to dig deeper into one of the more important parts of elimination and that's the beta-hydrogen.
All right, so you guys might remember that elimination reactions basically pull off beta-hydrogens and then they make double bonds. If you think back to the definition of elimination what we remember is that – let's say that you have a single bond to a leaving group and a single bond to a hydrogen, what winds up happening is that these two sigma bonds get pulled off and turned into one pi bond. That's the whole process of elimination. That's actually the definition is that two sigmas turn into one pi.
So that's not bad. But the tricky part comes in with the beta-hydrogens because it turns out that rarely will you just have one beta-hydrogen that applies towards this rule. Many times you're going to have several beta-hydrogens that you have to choose from. On top of that, that complicates things more because if you choose a different beta-hydrogen to extract that might actually make a new product. What that means is that we're opening ourselves up for the possibility of multiple products.
In this page, what I want to do is just really practice how to determine if you're just going to get one product or if you have a possibility of up to three products. Usually, that's the maximum amount of products you can get, three, because that's the maximum amount of beta-carbons you can have, three.
Let's go ahead and talk about how to figure that out. The way you figure that out is by counting the number of non-equivalent beta-carbons. So remember that the beta-carbon is attached to the alpha-carbon. I'm going to go through all this again, so it's fine. If those beta-hydrogens have at least one H, that's going to be its own unique product. So for every beta-carbon that's unique, that has it's own H that can be taken off, that's going to represent one possible product.
Like I said, sometimes you're just going to only have one product. Only one of the beta-carbons will have a hydrogen on it. But other times you're going to get up to three products and that's what we're going to do now.
I want you guys to look at example (a) and try it yourself. Try to figure out exactly how many different products you can get from (a) by looking at the beta-carbons and seeing if they have hydrogens. And then I'll explain the entire question, how to do it. So go ahead and get started.
For the following molecules, identify the number of unique products that could be obtained through elimination.
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