Chemistery

Let's compare E1 and E2 in the following aspects: Base Substrate Solvent Leaving Group Kinetics Stereochemistry Rearrangements  Base E1: As the base abstracts the proton only after the carbocation intermediate is formed, it does not affect the rate of reaction, hence not important. E2: A strong base is indeed needed to promote the one-step reaction. Substrate E1: A more substituted substrate stabilizes the carbocation intermediate.  E2: A more substituted substrate forms a more substituted alkene.  Solvent E1: A polarizing solvent enhances the rate of ionization as it pulls the cation and anion apart.  E2: The transition state is less sensitive to the solvent as the transition state has its negative charge shared over the whole molecule.  Leaving Group Both reactions need a good leaving group.  Kinetics E1: The rate is only determined by the substrate as it is the only molecule that ionizes. E2: Both the substrate and the base aff...

Similar to SN1, a carbocation intermediate is formed by an unimoleular ionization (rate-determining step). Then, a base (usually a weak base) abstracts a proton from the carbon which is next to the electrophilic carbon. A pi-bond is formed between these two carbons. Same as SN1, to stabilize the carbocation intermediate, a bulky/most substituted substrate is needed and rearrangements may occur. As the base attacks, the carbon next to the electrophilic carbon is rehybirdized to sp2 to form a pi-bond with the electrophilic carbon. E1 Mechanism SN1 or E1? Notice that both SN1 and E1 have the same unimolecular ionization first step and require a substituted substrate. So after the carbocation intermediate is formed, will the reaction go through the SN1 route or the E1? The answer is that we will have a mixture of E1 and SN1 product; the second step can either be a basic attack by the solvent (abstracts a proton to give an alkene) or an nucleophilic attack by the solvent on the c...

After introducing electrophile and nucleophile, let's talk about SN1 , SN2 , E1 and E2 . Let's see what they mean first: SN1: First-Order Nucleophilic Substitution SN2: Second-Order Nucleophilic Substitution E1: First-Order Elimination E2: Second-Order Elimination   So basically, these 4 types of reactions are categorized into   Nucleophilic Substitution and Elimination .  Nucleophilic Substitution means one thing is substituted by something else, which is a nucleophile (to make it nucleophilic) Elimination always form a double bond product because as something is eliminated, the remained  electrons form a double bond  The condition for each of these reactions are different (solvent, leaving group, reactant bulkiness, etc) and the ability to classify them is crucial. Here is a table summarized all we need to know about them.   source: www.pinstopin.com Our team at Chemistery uses NordVPN every day and we high...