Alkene Addition Reactions Flashcards

Comprehensive vocabulary flashcards covering alkene addition reactions, mechanisms, and reagents based on the provided lecture notes.

Hydrohalogenation

A reaction that results in the Markovnikov addition of a hydrogen ($H$) to the less substituted side and a halogen ($Cl$, $Br$, or $I$) to the more substituted side across an alkene, forming an alkyl halide.

Hydrohalogenation Reagents

The chemical reagents used are either $HCl$, $HBr$, or $HI$.

Markovnikov addition

A regioselectivity pattern where the substituent is added to the more substituted carbon of the double bond, while the hydrogen is added to the carbon with more hydrogens (less substituted side).

Rate Determining Step (RDS) in Hydrohalogenation

The first step where the pi electrons of the alkene attack a hydrogen, resulting in the formation of a high-energy carbocation intermediate.

Acid Catalyzed Hydration

The Markovnikov addition of a hydrogen and a hydroxyl group ($OH$) across an alkene to form an alcohol, utilizing a strong acid catalyst like $H_2SO_4$.

Oxonium ion

The intermediate formed in step 2 of acid-catalyzed hydration when water carries out a nucleophilic attack on the carbocation.

Oxymercuration-Demercuration

A reaction resulting in the Markovnikov addition of $H$ and $OH$ across an alkene to form an alcohol, exhibiting anti stereospecificity and avoiding carbocation rearrangements.

Mercurinium ion

A three-membered ring intermediate containing mercury ($Hg$) that forms during the first step of Oxymercuration-Demercuration.

Oxymercuration-Demercuration Reagents

Reagents added in two steps: 1. $Hg(OAc)_2$, $H_2O$; 2. $NaBH_4$.

Hydroboration-Oxidation

The anti-Markovnikov addition of a hydrogen to the more substituted side and a hydroxyl group ($OH$) to the less substituted side with syn stereospecificity.

Hydroboration-Oxidation Reagents

Reagents added in two steps: 1. $BH_3 \cdot THF$ (or $B_2H_6$); 2. $H_2O_2$, $NaOH$.

Trialkylborane

The intermediate formed during the hydroboration step after the boron atom attaches to the less substituted side of multiple alkenes.

Syn addition

A type of stereospecificity where the two added groups originate from the same face or side of the alkene.

Catalytic Hydrogenation

The syn addition of two hydrogen atoms across an alkene using a metal catalyst such as $Pd$, $Pt$, or $Ni$.

Halogenation of Alkenes

The addition of two halogen atoms ($Cl$ or $Br$) across an alkene to form a vicinal dihalide, proceeding with anti stereospecificity.

Halonium ion

A three-membered ring intermediate ($bromonium$ or $chloronium$) formed when pi electrons of an alkene attack a halogen molecule.

Anti addition

A type of stereospecificity where two groups are added to opposite sides of the alkene, often due to back-side attack on a three-membered ring intermediate.

Halohydrin Formation

The addition of a halogen to the less substituted side and a hydroxyl group ($OH$) to the more substituted side across an alkene, using reagents $X_2$ and $H_2O$.

Epoxidation

A reaction involving a peroxyacid (typically $MCPBA$) that adds a single oxygen atom across an alkene to form a three-membered ring called an epoxide.

MCPBA

Meta-chloroperoxybenzoic acid, the most common peroxyacid (peracid) used for the epoxidation of alkenes.

Anti Dihydroxylation

The anti-addition of two hydroxyl groups ($OH$) across an alkene, typically achieved through epoxidation followed by acid-catalyzed ring opening with water ($H_3O^+$).

Syn Dihydroxylation

The syn-addition of two hydroxyl groups ($OH$) across an alkene using reagents like 1. $OsO_4$, 2. $NaHSO_3$/$Na_2SO_3$, or cold, dilute $KMnO_4$ with $NaOH$.

Oxidative Cleavage

A reaction that breaks the carbon-carbon double bond to form carbonyl-containing compounds, using reagents like Ozonolysis ($O_3$) or Permanganate ($KMnO_4$).