Organic Chemistry chp. 8 Addition rxns

Hydrogenation catalysts Pt, Pd, Ni

Goes all the way to Alkane (Only one) and is syn addition of H‘s

Hydrogenation Lindlar’s catalyst (Pd/CaCO3), Ni2B (P-2), Quinoline

syn addition and stops at alkene

hydrogenation catalysts Na or Li

stops at alkene and is anti addition 

Hydrohalogenation 

Usually Markovnikov

Heat or ROOR make it anti-Markovnikov 

Occurs at DB

Addition reactions making alcohols (adding OH) and catalysts + solvent

• acid-catalyzed hydration (H2SO4 + H2O)

• Oxymercuration - Demercuraton (Hg(OAc)2 + NaBH4)

• Hydroboration - oxidation (BH3 + H2O, NaOH)

All occur at DB

Acid-catalyzed hydration (H2SO4 + H2O)

• Markovnikov

• syn or anti

• Forms carbocation first, so rearrangements

Oxymercuration - Demercuraton (Hg(OAc)2 + NaBH4)

• Markovnikov

• anti addition

• No rearrangements

Opposite of hydroboration - oxidation (H2O + NaOH)

Hydroboration-Oxidation (BH3 + H2O, NaOH)

• Anti Markovnikov

• syn addition

• no rearrangements

Opposite of Oxymercuration - Demurcuraton (Hg(OAc)2 + NaBH4)

Addition reactions for making Ethers (R-O-R) and catalyst + solvent

• Solvomercuration - Demercuration (Hg(OAC)2 + CH3OH)

Difference between this and oxymercuration - demercuration is solvent (NaBH4 vs CH3OH) and one makes alcohol and other forms ether

Occurs at DB

Solvomercuration - Demercuration (Hg(OAc)2 + CH3OH)

• Markovnikov

• anti addition of RO- and H

• no rearrangements

Same type of trend as of mercury 

Addition reactions making Dihalides (X2) solvent

• Halogenation (Cl2, Br2, F2, I2)

• Double hydrohalogenation (HBr, HCl, HF)

Halogenation occurs at DB 

Double hydrohalogenation occurs at TB

Halogenation (Cl, Br, etc.)

• Anti addition

• will make enantiomers

Double hydro halogenation (HCl, HBr, etc)

• Markovnikov and anti addition of first X and H. Then same thing after. 

• Makes Vic (adjacent carbons) or gem (same carbon) dihalides 

Addition reactions making tetrahalides 

• double halogenation (X2)

Occurs at TB

Double halogenation

• Markovnikov

• anti addition

• need two moles of (X2)

Making halohydrins (X + OH)

• halohydrin (X2 + H2O)

Occurs at DB

Halohydrin (X2, H2O)

• Ant addition of an OH and X

• OH binds to more substituted Carbon

Addition reactions making diols (2OH’s)

• KMnO4 (KMnO4, NaOH + cold/hot)

• Osmylation (OsO4 + H2S)

Bot occur at DB

(Seeing O4 means add two OH’s)

KMnO4 (Two types) 

• Cold results in syn addition of hydroxyl groups

• Hot results in cleavage into carboxylic acid 

Osmylation (OsO4)

• syn addition

Reactions making Ketones (R - - O - - R) and aldehydes (R - - O)

• Ozonolysis (O3) and alkene cleave DB

Addition reactions making carboxylic acids 

• Ozonolysis with alkyne 

• KMnO4 in heat

Ozonolysis occurs at TB and KMnO4 occurs at DB

Ozonolysis with Alkyne 

• Cleave TB and add O to end and attach OH to carbon

This releases CO2

KMnO4 with Alkyne or with heat

• Cleave DB or TB and add O with OH attached to C 

What carbons can Br2 react with in the dark

Alkenes and Alkynes but will not react with Alkanes

How do you make Osmylation cheaper

You add NMO