Bases and Nucleophiles

E2 happens in...

One step

NaOH

Strong base weak nucleophile

Strong base weak nucleophiles make what reactions?

1° ~ E2

2° ~ E2

3° ~ E2

Weak base strong nucleophiles make what reactions?

1° SN2

2° SN2

3° SN1

RS-

Weak base strong nucleophile

HO-

Strong base strong nucleophile

NaH

Strong base weak nucleophile

Cl-

Weak base strong nucleophile

MeO-

Strong base strong nucleophile

Br-

Weak base strong nucleophile

HS-

Weak base strong nucleophile

MeONa / NaOMe

Strong base strong nucleophile

DBU

Strong base weak nucleophile

tBuOK

Strong base weak nucleophile

DBN

Strong base weak nucleophile

H2S

Weak base strong nucleophile

H2O

Weak base weak nucleophile

EtOH

Weak base weak nucleophile

MeOH

Weak base weak nucleophile

Weak base weak nucleophiles make what reactions?

1° none

2° none

3° 50% SN1 and 50% E1

EtO-

Strong base strong nucleophile

EtONa / NaOEt

Strong base strong nucleophile

Strong base strong nucleophiles make what reactions?

1° 30% E2 and 70% SN2

2° 70% E2 and 30% SN2

3° E2

RSH

Weak base strong nucleophile

H2SO4

Weak base weak nucleophile

I-

Weak base strong nucleophile

Slow reactions mean what in terms of products?

They make one product

Fast reactions mean what in terms of products?

They make two products

Equation for optical purity (ee)

samples optical rotation/pure optical rotation

When adding HBr/ROOR where do you add Br and H?

Br gets added to the less substituted carbon

Diluted H2SO4 does what?

Adds H2O to the double bond

When adding diluted H2SO4 what goes where?

OH goes on the more substituted carbon

H goes on the less substituted carbon

Whats the difference between diluted H2SO4 and 1.BH3 x THF 2. H2O2/NaOH?

Diluted H2SO4 adds OH to the more substituted carbon, and BH3 adds OH to the less substituted carbon

Concentrated H2SO4 removes H2O it’s…

The reverse reaction for diluted H2SO4

When adding Br2 where does everything go?

One Br gets added to each side of the double bond

When adding Br2/H2O where does everything go?

OH goes on more substituted carbon

Br goes on less substituted carbon

In Br2/H2O Br and OH what?

Go on opposite sides

In 1. BH3 x THF 2. H2O2/NaOH where does everything go?

OH goes on the less substituted carbon

2 molecules form 1 product…

Delta S > 0 so the reaction becomes positive or less negative meaning delta G is positive and the reaction favors the reactants

1 molecule forms 2 products…

Delta S < 0 so the reaction becomes negative or less positive meaning delta G is negative and the reaction favors the products

A meso compound…

Must have at least 2 chiral centers

Steps for finding a meso compound

1. See if there are more then 2 chiral centers

2. Look for a plane of symmetry

3. Check R and S configurations

If 4 isn’t on a dashed line what can you do to find R and S?

Find the direction its going either R or S then switch it