Organic chemistry Reagents and basic reactions

Mix of mechanisms and Reagents

1. LiAlH4

1. Strong Reducing agent: Reduce all Carbonyl Functional groups to alcohols

2. mechanism:

3. The mechanism involves nucleophilic attack by the hydride ion on the carbonyl carbon, leading to the formation of an alkoxide intermediate that is then protonated by acid to yield the alcohol.

4. must use 2 molecules for COOH to get alcohol

NaBH4

Mild reducing agent: Adds one Hydrogen to the carbonyl group.

t-BuOH

Used to produce a double bond by depronating a hydrogen and allowing elimination to occur as the halide group leaves after forming a double bond.

1.NBS

2. RooR

Provides 1 Br atom to an allylic position( to the carbon atom that is adjacent to the DB). Avoids over-bromination of the double bond, ensuring selective bromination.

What is the Wittig Reagent and reaction

A phosphorus ylide used to convert aldehydes and ketones into alkenes through the Wittig reaction. Reagent: PPh₃

1. PPh₃ attacks a methyl halide and removing the halide group

2. A lithium hydrocarbon deprotonates the methyl to form a double bond between H₂C=PPh₃

3. H₂C=PPh₃ The DB attacks the Carbon in C=O after the oxygen attacks the Phosphorus.

4. two double bond are formed between C=CH₂ and O=PPh₃

5. reacts with the carbonyl compound to form an alkene and a triphenylphosphine oxide byproduct.

What is the Reagent of Tollen’s test and what does it test for

Reagent: Ag₂O/OH

Oxidizes aldehydes to carboxylic acids, testing for the presence of aldehydes is negative if aldehyde is not present.

Diel’s Alder’s reaction

Dienophile + Diene

EDG enhance the reactivity of Dienes while EWG enhances the reactivity of Dienophile

to form cyclohexene derivatives. It's a [4+2] cycloaddition reaction that synthesizes six-membered rings.

1. Bond is made between C₁-C₆

2. DB is made between C₂-C₃

3. Bond is made between C₄-C₅

What is the reagents and steps for Fiedel’s craft-Acylation

The Friedel-Crafts acylation reaction involves the use of an acyl chloride or an anhydride as the acylating agent, combined with a strong Lewis acid catalyst such as AlCl₃. This reaction introduces an acyl group into an aromatic ring, resulting in the formation of a ketone.

Grignard reaction

Reagent: RMgX (where R is an alkyl or aryl group) Ex: CH₃MgBr

1. Mechanism: The R group is partial negative charge due to the Magnesium pulling the positive charge, so R group acts like a nucleophile and under goes nucleophilic addition or subsistion.

2. Typically either a C-C bond would occur or a C=O bond is formed in the presence of a carbonyl compound, resulting in the formation of an alcohol after hydrolysis.

NaBH4

1. Mild Reducer: Can only convert Aldehyde and Ketone to alcohols

2. Mechanism: Uses the Hydride ion on the Boron to attack the carbonyl group making an alkoxide ion. The intermediate then gets protonated by diluted acid.

What reagents would you use to convert a Phenol to an ether

1. Reagent: 1. NaOH 2. Alkyl halide

what is the william ester synthesis Regent and reaction

1. Reagent: 1. NaOH 2. Alkyl halide

2. Regent can also be NaH if strong base is needed for deprotonation as it can deprotonate Primary alcohols in a hydrocarbon chain. NaOH is used to deprotonate Phenol

3. Mehcanism: step 1: Base deprotonates alcohol. Step 2: the resulting alkoxide attacks the alkyl halide to form an ether in a Sn2 reaction.

R-OH + KMnO₄ =

R-COOH Carboxylic acid with a side product of Water

What is a strong Oxidizing Agent

KmnO4

Imine Formation Reagent and mechanism

Reagent: NH2-R

Reaction of aldehydes or ketones with primary amines to form Imines. Imine = C=N-R.

Mechanism:

1. Nucleophilic addition from R-NH2 where N attacks Carbon in carbonyl

2. Proton transfer: Oxygen anion takes a hydrogen from R-N-R₂H₂

3. Protonation of OH to form water Ex: dilute acid H3O

4. Nu Elimination: C=NH-R bond forms resulting in the removal of water.

5. Deprotonation of C=NH-R ——> C=N-R Ex: dilute base OH

Imine + NaBH₃CN =

Imine = R-C=N-R

NaBH₃CN reduces imines to amines by

1. Hydride ion bonded to boron attacks the Carbon on C=N which moves the electrons from the double bond to the nitrogen after adding another hydrogen, converting the imine back to an amine.

2. The Nitrogen is now negatively charged with 2 lone pairs, so it gains a hydrogen by attacking BH2 to become an Amine

3. Product: R-C-NH-R

NaBH₃CN is similar to NaBH4

Hydrazine (N₂H₄)

ozonolysis Reagent and reaction

Reagent: 1. O₃ 2. DMS

is a reaction that involves the cleavage of alkenes or alkynes using ozone (O₃) to produce carbonyl compounds such as aldehydes or ketones.

1. Br₂, Hv 2. NaOEt

1. Radical reaction: Bromination

is a radical substitution reaction that involves the addition of bromine (Br₂) to alkenes or alkanes under ultraviolet light (Hv) to form bromoalkanes.

2. Forms a double bond that removes the Bromine from C-Br since X is an electron-withdrawing group and good leaving group.

EDG

1. Donates Electron to molecule or aromatic ring. It makes it more reactive and nucleophilic making it susceptible to Electrophilic Substitution reactions (EAS), enhancing reactivity towards electrophiles.

2. Increases the acidity: stabilizing the Conjugate Base through delocalization of (-) charge by Resonance

3. Increase the basicity: Providing lone pairs of Electrons that can accept protons. Increase the Electron density.

4. Ex: Orth/ para Activating

   1. -NH₂, -OH, -OCH3, -R (alkyl groups), -Ph, -NHCOCH₃

Enamine Formation

Reagent:

Reagent: secondary amine CH2-CH2-CH2-NH-CH2

Mechanism:

1. Nucleophilic addition from R-NH2 where N attacks Carbon in carbonyl

2. Proton transfer: Oxygen anion takes a hydrogen from the secondary amine

3. Protonation of OH to form water Ex: dilute acid H3O

4. Nu Elimination: C=NH-R bond forms resulting in the removal of water.

5. Move the double bond to the more substituted carbon in the enamines, stabilizing the double bond.

Formation of OrganoLithium Reagent that is used for Grignard Reagent

Mechanism:

1. Single Electron Reduction: 1 electron from lithium or Magnesium( any metal) attacks the halide of an Alkyl halide

2. Fragmentation: A radical intermediate is formed as Br^(-) and Li⁽⁺⁾ form a lithium alkyl intermediate One radical is moved to the carbon after LiBr is formed

3. Organolithium molecule is formed when another Lithium ion bonds to the radical present on the carbon. This molecule can now participate in Grignard.

R-X ——>Mg,R-O-R

what is the product of this

Grignard reagent formation from alkyl halide using magnesium, resulting in an organomagnesium compound.

What Reagent is needed to convert an Acid chloride to an Ester

Primary Alcohol

Alkene Reacts with what Reagent for it to lose its DB

Br₂/CH2Cl₂