Substitution vs. Elimination Reactions

Flashcards covering key concepts and mechanisms of substitution and elimination reactions in organic chemistry.

What are the two types of substitution reactions?

SN1 and SN2.

What does SN1 stand for?

Substitution Nucleophilic Unimolecular.

What characterizes the SN1 mechanism?

It includes a slow step where the substrate loses its leaving group and forms a carbocation.

What is a key feature of the SN2 mechanism?

It occurs in one step with a backside attack leading to inverted stereochemistry.

What type of carbon substrates favor SN2 reactions?

Primary carbon substrates.

What is the role of the nucleophile in substitution reactions?

The nucleophile is an atom containing a lone pair or pi bond that attacks the substrate.

What is Zaitsev's Rule in the context of elimination reactions?

The most substituted alkene is the most stable and major product.

What are beta hydrogens?

Any attached hydrogens to the beta carbon in elimination reactions.

In an SN1 mechanism, what type of hybridization does the carbon have?

sp3 hybridization.

What is an E1 reaction?

A unimolecular elimination reaction that involves the formation of a carbocation before elimination.

In an E2 reaction, what must the leaving group and hydrogen conform to?

They must be in the same plane but on opposite sides (antiperiplanar).

What factors influence the choice between SN1 and SN2 mechanisms?

The structure of the substrate, the strength of the nucleophile, and the leaving group's ability.

What is a key difference between E1 and E2 reactions?

E1 involves carbocation formation while E2 is a bimolecular reaction that occurs in one step.

What type of solvent favors SN1 reactions?

Polar protic solvents.

What nucleophilicity trend is observed on the periodic table?

Nucleophilicity increases down a group.

What type of carbocation forms during an SN1 reaction?

A carbocation intermediate.

What does the nucleophile do in an E2 reaction?

Acts as a base and takes a beta proton, leading to elimination.

What is produced when a leaving group leaves during an elimination reaction?

A double bond is formed between the alpha and beta carbons.