Download Slides for Chapter 1-4 - Department of Chemistry and Physics

Organic Chemistry Supplement
Alkyl Halides React with Nucleophiles and
Bases
 Alkyl halides are polarized at the carbon-halide bond,
making the carbon electrophilic
 Nucleophiles will replace the halide in C-X bonds of
many alkyl halides(reaction as Lewis base)
 Nucleophiles that are Brønsted bases produce
elimination
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11.2 The SN2 Reaction
 Reaction is with inversion at reacting center
 Follows second order reaction kinetics
 Ingold nomenclature to describe characteristic step:



S=substitution
N (subscript) = nucleophilic
2 = both nucleophile and substrate in
characteristic step (bimolecular)
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SN2 Transition State
 The transition state of an SN2 reaction has a planar
arrangement of the carbon atom and the remaining
three groups
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Stereochemistry of SN1
Reaction
 The planar
intermediate
leads to loss of
chirality
 A free
carbocation is
achiral
 Product is
racemic or has
some inversion
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11.6 Biological Substitution
Reactions
 SN1 and SN2 reactions are well known in
biological chemistry
 Unlike what happens in the laboratory,
substrate in biological substitutions is often
organodiphosphate rather than an alkyl halide
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11.8 The E2 Reaction and the
Deuterium Isotope Effect
 A proton is
transferred to base
as leaving group
begins to depart
 Transition state
combines leaving of
X and transfer of H
 Product alkene forms
stereospecifically
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This can be extended to
Phosphoanhydride
bonds found in ATP
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