Reactions Flashcards
Which step is slow for Electrophilic Additions?
First step
What does the first step of electrophilic additions form?
Carbocations
Another term for Nucelophile
Lewis Base
Another term for Electrophile
Lewis Acid
Lewis Base
Gives up an electron pair
Lewis Acid
Accepts electron pair
What should you always look for for electrophilic additions?
Rearrangement of carbocation
Types of rearrengement
Hydride shift, methyl shift, and ring expansion.
Markovnikov’s Rule
Nucleophile attached to most substituted carbon.
First 5 Electrophilic Additions
- Addition of a Hydrogen Halide (HX)
- Antimarkovnikov HBR
- Acid Catalyzed Hydration
- Addition of a Br2 or Cl2
- Formation of a Hydrogenated Alcohol (halohydrin)
Addition of a Hydrogen Halide (HX) properties
Markovnikov, Br = regioselective, HBr faster than HCl, possibility of polar solvent
Peroxide presence indicates what?
Free radical mechanism
What does the most substituted carbon mean?
Carbon with the least amount of hydrogens.
Properties of Antimarkovnikov HBr
Free radical mechanism, Antimarkovnikov, only HBr, presence of peroxide leads to antimarkovnikov.
Acid Catalyzed Hydration required reagents
Nu: H2O and E: H+ (acid)
Acid Catalyzed Hydration Properties
Markovnikov and look for rearrangement.
Stereospecificity
Stereochemistry of reactants determines stereochemistry of products. Hence look at Stereochemistry
Solvents for addition of Br2 or Cl2
CCl4 or CH2Cl2 inert solvent
Properties of Addition of Br2 or Cl2
Antiaddition (use of bridge), stereospecificity for cycloalkenes (look at stereochemistry).
Halohydrin
Halogenated Alcohol
Formation of a halogenated alcohol (halohydrin) properties
Antiaddition (use of bridge), OH attaches to most substituted carbon (due to charge stability), and look at stereochemistry.
Last 5 electrophilic addition reactions
- Addition of Sulfuric Acid - like hell - remember 6
- Hydroboration/Oxidation
- Formation of a Diol (glycol)
- Formation of Aldehydes + Ketones
- Hydrogenation
Formation of a halogenated alcohol required solvent
excess H2O
Sulfuric Acid formula
H2SO4
Addition of Sulfuric Acid solvent requirements
dilute H2O and heat