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8 Cards in this Set
- Front
- Back
What are the 3 rules in the Cahn-Ingold-Prelog theory?
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applies for TRISUBSTITUTED
Rule 1: look at the two atoms attached to each double-bond carbon and rank them according to atomic number Rule 2: If a decision cannot be made by ranking the first atom in the substituent, look at 2nd or 3rd until difference is found Rule 3: multiple bonded atoms are equivalent to same number of single-bonded atoms |
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How can interconversion be attained between cis and trans isomers?
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1. a strong acid (establishes equilibrium)
2. light can be absorbed by the double bond 3. heat sufficient to break the pi bond |
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What is hyperconjugation?
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stabilizing interaction between the C=C pi bond and the adjacent C-H sigma bond on substituents
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What is a regiospecific reaction and what is Markovnikov's rule?
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Regiospecific reactions:
-reactions where only one of two possible orientations occurs Markovnikov's rule: In the addition of HX to an alkene, the H attachces to the carbon with fewer alkyl substituents and the X attaches to the Carbon with more alkyl substituents -in otherwords, the more highly substituted carbocation is formed as the intermediate |
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What are properties of carbocations?
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carbocations are planar
carbon is sp2 and has a vacant p orbital perpendicular to the plane of the carbon carbon has 3 attached groups |
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What is the inductive effect in carbocation structure and stability?
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inductive effect:
-transmitted through sigma bonds -results from electronegativity of nearby atom (C+ is very electropositive) -alkyl groups are electron donating so the more there are the more it will stabilize the carbocation |
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What is the Hammond Postulate?
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Transition states represent energy maxima whose structures are more similar to the structure of the less stable adjacent species
structure of a transition state resembles the structure of the nearby stable species any factor that stabilizes the carbocation should also stablize the nearby transition state, TS stabilized by hyperconjugation and inductive effects transition states for endergonic steps resemble products transition states for exergonic steps resemble reactants |
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What is an example of a place where a hydride shift would occur?
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in biosynthesis of cholesterol
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