Oxidation/Reduction/Ether/Epoxides Reactions and Reactants

1) LiAlH4

2) Dil HA

NaBH4 and MeOH

1) R’’—MgBr

2) Dil HA

SOCl3 in pyridine

PBr3 in Pyridine

CrO3, H2SO4, acetone

PCC or DMP

PCC

H-X and heat (X=Cl, Br)

Cat. OsO4 and NMNO

1) mCPBA

2) H3O+

and Et3N

H2SO4 and Heat

OR

POCl3 and Et3N

TsCl in pyridine

TIPS-Cl and Et3N

nBu4N+F- and H2O

(TBAF and H2O)

1) PBr3 in Pyridine

2) Na—x

1) TsCl in Pyridine

2) Na—x

NaOH + Sn2 conditions

H2O + SN1 Conditions

H2SO4, H2O

1) BH3, THF

2) H2O2, NaOH, H2O

1) BH3, THF

2) H2O2, NaOH, H2O

H2SO4, H2O

DMP

Na—X

1) Na + and H-

2) R’—X

1) Na + and H-

2) Me—X

H2SO4, H2O

MeOH, H2O

O2

O2

O2

MCPBA

Or

1) X2 (Cl or Br)

2) NaH

HBr and Heat

HBr

1) Me—Mg—Br

2) dil acid

The grignard reaction fails under the presence of what?

Acidic protons such as phenols, amines, carboxylic acids, terminal alkynes and alcohols. They immediately protonate the reagent and destroy it.

Why can’t tertiary alcohols be oxidated?

Oxidation reactions are the loss of an alpha hydration. Tertiary alcohols lack the alpha hydrogen, so they are resistant.

Oxidation rate of alcohols

2 > 1 > 3

• secondary alcohols just oxidize to ketones and stop

• primary alcohols go through an aldehyde, then a carboxylic acid

Draw mCPBA

Draw O5O4

Draw NMO

Draw PCC

Draw DMP

Conversion of alcohols to esters rates?

1 > 2 > 3

• depends on steric hindrance.

From an epoxide reaction formation, when should mCPBA be used?

the two options to form an epoxide are:

mCPBA or 1) X2 2)Nah

It should be used if a molecule has acid sensitive groups or can be destroyed by water or x2

Why are smaller rings happier to open?

Severe ring strain, the ideal bond angle is 109.5 degrees and it’s being forced into 60 degree angle

In acid catalyzed ring-opening of epoxides, how do major and trace amount products change in acidic and basic reactions?

In acidic conditions (H3O+, H2SO4, H-X):

• Nucleophile attacks the most substituted carbon or benzylic carbon and alcohol goes into the least substituted carbon

• Protonation of the oxygen makes it a good leaving group, creating a partial positive charge on the more substituted carbon

In basic conditions(OH-, OR-, CN-):

• Nucleophile attacks the less substituted carbon and alcohol goes on the most substituted carbon

• Strong nucleophiles prefer the less hindered carbon via an SN2 mechanism

Electron-withdrawing groups (EWG) do what to pka?

lower it —- increases acidity

Stabilize and result in a stronger acid because acidity depends on the stability of the conjugate base

Electron-donating groups (EDG) do what to pka?

increase pKa — lowers acidity

Destabilize and result in a weaker acid because acidity depends on the stability of the conjugate base

What are some solvent for SN2 reactions?

polar aprotic

(acetone, DMSO, DMF, MeCN, HMPA, THF, acetonitrile, dichloromethane)

What are some solvent for SN1 reactions?

polar protic

water, alcohols, and carboxylic acids

HgSO4

H2SO4

first: H2, pd/c

second: H2, lindlar’s catalyst

third: Na, NH3 (l)

Gringards reagent can also pop open epoxides, what determines major and minor?

Sterics, nucleophile will attach itself to the least substituted carbon