Organic Chemistry 1

Reaction mechanisms and conditions

Addition of hydrogen halides to alkynes

H+ is the electrophile, catalysts are:HF,HBr,HCl,HI

Additions of halogens to alkynes

Acid catalyzed hydration/hydroboration of an alkyne (INTERNAL ALKYNE)

Acid catalysed hydration/hydroboration of an alkyne (TERMINAL ALKYNE)

Addition of hydrogen to an alkyne

3 different mechanisms

Stereo chemistry hydroboration

syn adition

Sn2

• back attack

• polar aprotic solvent

• inversion of stereochemsitry

• strong nucleophile

• good leaving group

• needs space for nucleophile to attack

Sn1

• carbocation intermediate

• 2 step

• racemization

• polar protic solvent

E2

• one step reaction

• Base removes proton and leaving group leaves in one step

• Tertiary>secondary>primary

• Only anti elimination if 2 hydrogens, (consequence is it must be antiplanar product)

• strong base

E1 reactions

• two step reaction

• weak base

• anti and syn elimination

• largest substituted isomer is major product

Common protic solvents

• H2O

• HCOOH

• CH3OH

• HC3HC2OH

• CH3COOH

Common aprotic solvents

• DMF

• DMSO

• Acetone

• THF

• Toluene

Halogenation (electrophilic aromatic substitution)

• each carbocation has three resonance structures

Iodination(electrophilic aromatic substitution)

Nitration of benzene

Sulfonation of benzene

Fiedel-Crafts acylation

Fiedel-Crafts alkylation

Wolf-kishner reduction

Formation of diazonium ion from aniline

Nucleophilic aromatic substitution

What is the major product of

• Nitration

What is the major product of

• strong base

  • E2 reaction

What is the major product of

What is the major product of

reduction of acyl group on benzene