AlkenesAddition ReactionsSynthesis

Addition of HBr or HClMarkovnikov Addition

HBr Addition with RO-ORAnti-Markovnikov

Free-Radical Mechanism

Addition of Br2

A Similar Mechanism to the Addition of HBr?

Trans is formed exclusively(No cis is formed)

Carbocation can be Stabilized by Neighboring Br

Bromonium Ion is Opened Equally from Both Sides

DefinitionsStereospecific only one stereoisomer is formed at the expense of the other (e.g. trans vs. cis)Stereoselective one stereoisomer is formed preferentially over the other.

Anti-Addition Stereospecific ReactionAnti-addition

Bromonium Ion Intermediate

Halohydrins

Bromohydrin FormationAddition of Br OHStereospecific & Regiospecific

Unsymmetrical Bromonium ionH2O opens ring at more hindered site

Br and OH are trans in anti addition

Catalytic Hydrogenationsyn addition

Mechanism Syn Addition

Syn Addition of H2

Hydrogenationall alkene p bonds are reduced

Hydrogenated Vegetable Oil

HydrationAddition of H2O

Oxymercuration HydrationMarkovnikov additionRegiospecific Reaction

Oxymercuration Mechanism

Predict the Oxymercuration Hydration Products

What Alkene would you use to Make These Alcohols?

Hydroboration Hydration Anti-Markovnikov Syn addition

BH3 adds to Alkene

Hydroboration

Regiochemistry is Anti-Markovnikov

Syn Addition of H2O

Draw the Major Products

2 Complementary Hydration Reactions

Oxymercuration the more highly substituted alcohol formsHydroboration the less highly substituted alcohol forms

Predict Both Oxymercuration and Hydroboration Products

Cyclopropanation

A Carbene is Similar to Geometry of a Carbocation

Dichlorocarbene Reactions

Simmons-Smith Reaction

In situ Preparation of Carbene

Two MCAD Inhibitors

Epoxide PreparationFrom Alkenes

Epoxide PreparationFrom Halohydrins

Mechanism

Epoxide groups are Common in Biologically Active Molecules

A New Class of Anti-tumor Agents

Ozonolysis Forms 2 Carbonyl Compounds

OzonolysisAlkene Cleavage

Mechanism of Ozonolysis

What Alkene will Undergo Ozonolysis to Give the Products Shown?

Addition polymers

Air Pollution Reacts with Tires

O3 reacts with all alkene p Bonds

Problem A symmetrical unknown compound A, C8H16, reacts with H2 on a 1% Pt/C catalyst to form B (C8H18). Treatment of A with O3 followed by Zn/HOAc affords butanone only. Identify A and B.