CHE230 Exam 3 Steelman

Is SN2 Reaction One Step or Two Step?

One step, concerted

What kind of reagent does an SN2 process require ?

A strong Nucleophile. (I, Br, HS, OH, MeO, EtO, H2S)

What kind of solvent do SN2 reactions prefer ?

Polar Aprotic. No H-O or N-H.

How does SN2 effect stereochemistry ?

Inversion. The nucleophile attacks the opposite side of the LG.

Is the Sn1 reaction one step or two step?

2 step

What kind of reagent can an SN1 process use?

A strong or weak nucleophile

What kind of substrate can undergo SN2?

Methyl>1>2

What kind of substrate can undergo SN1?

3>2

How does SN1 effect stereochemistry?

Creates a racemic mixture of inverted and retained

What kind of solvents can be used for SN1 reactions?

Polar protic. Includes (H-O) or (H-N)

How many steps is an E2 reaction?

Concerted, 1-step

What kind of reagent does an E2 process require?

Strong base. (MeO, NaOH, KOH, NaCN)

What kind of solvent do E2 reactions prefer?

Polar Aprotic.

What kind of substrate do E2 processes prefer?

Can be tertiary secondary or primary

What is the Zaitsev product?

The more substituted alkene

What is the Hoffman product?

The least substituted alkene

How is zaitsev product formed?

By using a small base (EtO, MeO)

How is the Hoffman product formed ?

By using a large base. (T-butyl)

Is E1 Reactions one step or two steps

Two step

What kind of reagent is used for a E1 reaction ?

A strong or weak base

If substrate is methyl or primary

Reaction must be SN2 or E2

What kind of substrate does E1 prefer?

3>2

What kind of solvent does E1 prefer

Polar protic

What kind of product does an E1 reaction favor?

Zaitsev

NaH

Weak nucleophile, strong base

DBN

Weak Nucleophile, strong Base

DBU

Weak nucleophile, strong base

OH

Strong Nucleophile, strong Base

MeO

strong nucleophile, strong base

EtO

Strong nucleophile, strong base

I, Br, Cl

Strong nucleophile, weak base

HS-, H2S, RS-, RSH

Strong nucleophile, weak base

H2O

weak nucleophile, weak base

MeOH

weak nucleophile, weak base

EtOH

weak nucleophile, weak base

If a substrate is secondary, and an E2/SN2 process occur, which product is major

The E2 product

If a substrate is primary, and an E2/SN2 process occurs, which product is major

SN2

Primary substrate + strong base/weak nu

E2

Primary substrate + weak base/strong nu

SN2

What is added in a hydrohalogenation reaction?

A hydrogen and a halogen

What reagents can be used in hydrohalogenation?

H-Br, H-Cl, H-I

What is the maokovnikov product ?

When the halogen is added to the most substituted carbon

What is necessary for anti-maokovnikov product?

ROOR

How can an alkyne undergo hydrohalogenation?

If excess reagent is used (xs)

What is an acid catalyzed hydration ?

The addition of OH and H across a double bond

What reagents are used for acid catalyzed hydration of Alkenes ?

H3O+ or H2SO4 or H2O & [H+]

What is formed when an ALKYNE undergoes acid-catalyzed hydration ?

A ketone

What reagents are used in the acid catalyzed hydration of an ALKYNE

Hg(SO4), H2O

Where does the OH add in an acid catalyzed hydration of an Alkene

To the most substituted carbon (markovnikov)

What is achieved in a hydro-boration oxidation?

Anti-markovnikov addition of OH and H

What reagents are necessary for hydro-boration oxidation?

1.)BH3 * THF 2.) H2O2, NaOH

Where does OH add in a hydroboration oxidation?

To the least substituted carbon

What is the stereospecificity of a hydroboration oxidation of alkene ?

Syn addition. (But only if Chiral centers are created)

What is formed when an ALKYNE undergoes hydroboration oxidation ?

Aldehyde

What reagents are used for the hydroboration oxidation of an ALKYNE

1.) a sterically hindered borane (9-BBN)

2.) H2O2, NaOH

What is achieved in Catalytic Hydrogenation

Addition of 2 Hydrogen atoms

What reagents are necessary for catalytic hydrogenation of an ALKENE

1.)H2 2.) metal: Pt, Pd, Ni, Wilkinson's catalyst

Is catalytic hydrogenation a syn or anti addition?

Syn

When does catalytic hydrogenation produce 1 product with no enantiomer ?

If product is Meso, meaning two chiral centers and symmetry

What is achieved in a Halogenation reaction?

2 halogens are added across an alkene

What reagents can be used for halogenation

Cl2 or Br2

In halogenation, do halogens add syn or anti?

Anti

What happens in the formation of a halohydrin ?

A halogen and OH are added

What reagents can be used for halohydrin formation?

1.)Br2, Cl2 2.) H2O

In halohydrin formation, do the halogen and OH add syn or anti?

Anti

In halohydrin formation, which side does the OH add to?

The more substituted side

What is anti-dihydroxylation ?

The addition of 2 OH on opposite sides of alkene

What reagents are needed for ANTI dihydroxylation

1.) peroxy acid, R-CO3H or m-CPBA 2.) H3O

What is syn dihydroxylation?

Addition of OH groups on the SAME side of alkene

What reagents can be used for SYN dihydroxylation?

1.)OsO4 2.)NaSO3, H2O OR 1.)KMnO4, NaOH, cold

What is ozonolysis?

Cleaving a C=C bond to form 2 C=O bonds

What reagents are used in Ozonalysis

1.)O3 2.)DMS

If a non-benzene ring undergoes ozonalysis, how many products will be formed ?

1

If a non-ring alkene undergoes ozonalysis, how many products will be formed ?

2

To draw the products of an Ozonolysis reaction you should?

Erase the middle of each alkene and place two oxygens double bonded to each end