Organic Nucleophilic Substitutions and Eliminations

general nucleophilic substitutions proceed how

electron pair on nucleophile attacks carbon atom with a partial positive charge bound to an electronegative atom (leaving group)

nucleophiles are often BLANK charged

negatively

a 1 step nucleophilic substitution is called

bimolecular

bimolecular reactions are also reffered to as

Sn2

Sn2 reactions are

first order

2 step nucleophilic substitutions are called

unimolecular

unimolecular reactions are also referred to as

Sn1

In an Sn1 mechanism, which step is rate determining?

ionization

In regards to what is an Sn1 ionization first order

alkyl substrate concentration

Identify the mechanism

Sn2

Identify the mechanism

Sn1

unimolecular reactions produce

racemized tetrahedral stereocenters bearing the nucleophile

bimolecular reactions happen via

inversion of configuration at carbon center

in nucleophilic elimination, the nucleophile acts as a

base

The removal of the acidic proton, and the departure of the leaving group produces a BLANK from the alkyl substrate

alkene

One step elimination reactions are referred to as

E2 mechanisms

Two step elimination reactions are referred to as

E1 mechanisms

Identify the mechanism

E2

Identify the mechanism

E1

The major product of a nucleophilic reaction is substitution if the leaving group is on a

primary carbon

The major product of a nucleophilic reaction is elimination if the leaving group is on a

tertiary carbon

bimolecular reactions are faster on BLANK carbon atoms

primary

unimolecular reactions are faster on BLANK carbon atoms

tertiary

If the alkyl substrate is secondary, and the nucleophile is a strong base, what is the dominant reaction

E2

If the alkyl substrate is secondary, and the nucleophile is a weak base, what is the dominant reaction

Sn2

If the alkyl substrate is secondary, and the nucleophile is poor, what is the dominant reaction

Slow Sn1/E1 in polar protic solvents

If the alkyl substrate is primary, and the nucleophile is a strong base, what is the dominant reaction

Sn2 (E2 with non-nucleophilic bases)

If the alkyl substrate is primary, and the nucleophile is a weak base, what is the dominant reaction

Sn2

If the alkyl substrate is primary, and the nucleophile is poor, what is the dominant reaction

no reaction

If the alkyl substrate is tertiary, and the nucleophile is a strong base, what is the dominant reaction

E2

If the alkyl substrate is tertiary, and the nucleophile is a weak base, what is the dominant reaction

Sn1/E1 in polar, protic solvents

If the alkyl substrate is tertiary, and the nucleophile is poor, what is the dominant reaction

Sn1/E1 in polar, protic solvents

Strong bases favor the elimination product from what carbon atoms

secondary and tertiary

Weak bases produce more BLANK products mostly via BLANK

substitution, unimolecular

Hindered bases favor a BLANK product in all degrees of carbon atoms

elimination

Rates of substitution and elimination reactions are favored by better

leaving groupsW

What makes a good leaving group?

weak bases

Protonation of a poor leaving group makes it a weaker base and therefore

a better leaving group

What mechanistic step is most common in all of organic chemistry

protonation