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What does second order depend on? What don't second order reactions do?
What do all elimination reactions form?
- concentration of two species
- do not compete with first order reactions
alkenes
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What do you need if new bonds are formed?
What do first order reactions have?
a leaving group
intermediates
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In substitutions, our base is a __ or a __.
- the rate of the reaction is dependent upon __.
Second-order reactions have __.
- Lewis base or nucleophile
- concentration of electrophile and nucleophile
no intermediates
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A leaving group must be on __. If there's too much __, there may not be a __.
- the sp3 center
- steric tension
- leaving group
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As you go down a period table, __ increases, __ decreases.
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Elimination wants a __. SN2 wants __.
What is one of the best nucleophiles?
- strong base
- a sufficient one
- Iodine
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If you use a strong base, you run the risk of __.
deprotonating
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Leaving groups can what?
OTs= __
- be kicked out of the molecule
- tosylate is a good leaving group; if you see it, its leaving
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Elimination reactions produce what?
E2 is __.
What are the conditions of E2?
What does it do to the electron?
- more products
- one step
- similar
- pluck off
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How would we be able to determine a substraet?
look at the size and nature of the base and nature of the substrate
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What is the alpha position? Beta position?
If you have a hydrogen that is __ to the _, they must be __ apart.
- alpha position is the carbon bearing the leaving group
- beta group is the position adjacent to the leaving group
- anti
- leaving group
- 180 degrees
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Nucleophile behaves as a __, which __, kicks out the __, and forms a __.
- Bronsted- Lowry base
- deprotonates
- leaving group
- pi bond
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Primary alkyl halides typically undergo __, regardless of the strength. May produce __ and __ products.
- elimination
- major and min problems
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High temperatures favor __.
Stereochemistry of E2: In a Fischer projection, the groups on the same side are both __. Do we want that? What do w do?
- elimination
- eclipsed
- no
- redraw
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What are some good bases?
- NaOH
- NaOCH3
- NaOCH2CH3
- KOC(CH3)3
- NaNR2
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E2 reactions have a specific orientation= must be __. __ will determine the product.
When looking at the conformation and seeing wedges and dashes, what will occur?
- anti
- reactive conformation
wedges will be on the same side and dashes will be on the same side, in terms of top and bottom
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Leaving groups on rings?
Which position is least reactive? What must be done?
one must be straight up, the other=straight down
- equatorial
- you must flip the chair conformation to make it axial
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What must simple cyclos do? How do you achieve this?
adopt an unstable position; heating up the reactant will allow more equilibrium to occur, thus leading to an increased amount of unstable products
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Zaitsev's rule?
the alkene that prevails is the most highly subbed; more than one alkene product will be formed
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Hyperconjugation?
the more associations with neighboring bonds, the lower energy it is
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When trying to determine which beta hydrogen will react in a ring, what do you have to do?
What are the only H's that can move?
make a chair conformation
the ones that are anti (axial) to the other
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Even if a double bond is a more stable bond, if it does not have a beta hydrogen in an anti-axial position, what can't it do?
it cant react
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In SN1 and E1, what do you want?
What is it called?
What do they do more than the Sn2 reactions?
SN1 and E1 work well on what?
What is the rate reaction?
a solvent with a pair of electrons, not a strong nucleophile or base
solvolysis
compete more
tertiary reactions
first order
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What do SN1 and E1 form?
a polar intermediate= carbocations, which have the same stabilities as free radicals 3>2>1>CH3X
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What do you do to the first order reactions?
- In ___, it dissociates.
What determines it?
warm up in excess solvent
polar protic solvents
whether or not you can access the carbocation (the more highly subbed, the more accessible)
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First order rate reactions form?
form intermediate and take to product
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