CHEM 3410: Chapter 14
10 Cards in this Set
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Conjugated Diene
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Alkene with alternating double and single bonds
More stable than non-conjugated diene
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1,2–Addition
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The addition of a reactant to the two ends of a double bond.
C==C + A--B ---> C----C
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A B
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Kinetic Product
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the product that is formed fastest; the major product under kinetic control
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1,4- Addition
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Happens in conjugated dienes. The nucleophile adds to the 1 Carbon and the 4 Carbon.
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Thermodynamic Product
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When a reaction produces more than one product, the most stable product is the thermodynamic product
Dominates when reaction is reversible
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Energy Diagram
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Kinetic Product (1,2- Addition) has higher potential energy than the thermodynamic product (1,4- Addition).
At the lower temperature the 1,2- Addition is favored.
At the higher temperature the 1,4- Addition is favored.
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Diels-Alder Reaction: Cycloaddition
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Cycloaddition Reaction
addition of a diene to a dienophile to form a
cycloalkene
Takes place in one step: all the bonds break and form simultaneously
Converts 3 pi bonds → two new sigma bonds (C–C) and one new pi bond (on in-between segment of diene
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Pericyclic Reaction
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A reaction involving concerted reorganization of electrons within a closed loop of interacting orbitals. Cycloadditions are one class of pericyclic reactoins
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S-cis Conformation
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A cis-like conformation of a single bond in a conjugated diene
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Dienophiles
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The best dienophiles are electron poor due to the presence of electron withdrawing groups.
Those with a double bonded C=O or a triple bonded CN attached to the double bond diene must be able to obtain a s-cis conf.
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CHEM 3410: Chapter 14