Transcript Addition Reactions

Chapter 5
Reactions of Alkenes and
Alkynes
Dr. Sujatha Krishnaswamy
Chemistry Faculty
Chandler Gilbert Community College
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Chapter 4 Problem 18
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Chapter 4 Problem 17
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Addition Reactions
The characteristic reaction of alkenes is addition—the  bond is
broken and two new  bonds are formed.
Because alkenes are electron rich, simple alkenes do not react
with nucleophiles or bases, reagents that are themselves
electron rich. Alkenes react with electrophiles.
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Hydrohalogenation - Addition of HX
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Chapter 4 Problem 14
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To draw the products of an addition reaction:
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Addition of HX is regioselective
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Markovnikov’s rule: in additions of HX, H adds to the carbon
with the greater number of hydrogens
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Stability of Carbocations
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Chapter 5 Problem 3
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Predict the major product in each
reaction.
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More reactions…..
Chapter 5 Page 112 Problem 4
Page 116 Problem 10
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Synthesis
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Addition of H2O, Hydration

acid-catalyzed hydration of an alkene is
regioselective; hydrogen adds preferentially to the
sp2 carbon with less # of hydrogens.
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What products are obtained upon
hydration of the following alkenes?
Synthesis - How can you make these
alcohols?
Addition of Cl2 and Br2
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addition is stereoselective
stereoselective reaction: a reaction in which one
stereoisomer is formed or destroyed in preference to
all others that might be formed or destroyed
addition to a cycloalkene, for example, gives only a
trans product
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Reduction of Alkenes
Alkenes react with H2 in the presence of a transition metal
catalyst to give alkanes
the most commonly used catalysts are Pd, Pt, and Ni
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Predict the products of hydrogenation
(reduction) of
Alkynes
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Addition of HX to Alkynes
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Addition of Halogens to Alkynes
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Hydration of Internal Vs Terminal Alkynes
Keto-enol tautomers
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Addition of Hydrogen to Alkynes
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Reduction of an Alkyne to an Alkane
Alkane formation:
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Addition of Hydrogen to Alkynes
- Formation of cis Alkene
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Conversion of Internal Alkynes to trans Alkenes
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Summary of Alkyne Reductions
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