Term
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Definition
| when p orbitals are aligned parallel to each other & are close enough to overlap; ex) part of the double bond between carbons in alkenes |
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Term
| The electron density in a pi bond is distributed over both carbons _____ and _____ the molecular plane |
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Definition
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Definition
| the process of measuring the energy required to interconvert the cis form of a substituted alkene with its trans isomer; used to predict pi bond strength; involves the two p orbitals making up the pi bond being rotated 180 degrees |
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Term
| Which is stronger: a sigma bond or a pi bond? |
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Definition
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Term
| Alkyl substituents are inductive _____ donors to the pi bond |
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Definition
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Term
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Definition
| when an alkene and hydrogen gas are mixed in the presence of catalysts such as palladium or platinum, two hydrogen atoms add to the double bond to give the saturated alkane; very exothermic |
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Term
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Definition
| the heat released in hydrogenation; typically about 30kcal per double bond |
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Term
| The most general approach to the formation of alkenes is _____, in which two adjacent groups on a carbon framework are removed |
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Definition
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Term
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Definition
| certain hydrogens are more likely to be eliminated in a reaction than others |
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Term
| Elimination proceeds through attack by the base on one of the neighboring hydrogens situated _____ to the leaving group |
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Definition
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Term
| Eliminations that lead to the more highly substituted alkene are called _____ |
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Definition
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Term
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Definition
| the double bond forms preferentially between the carbon that contained the leaving group & the most highly substituted adjacent carbon that bears a hydrogen |
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Term
| The most stable alkene is formed by a double bond between the carbon containing the leaving group and _____ |
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Definition
| the most substituted carbon that also bears an elimination hydrogen |
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Term
| When a bulky base is used, more of the _____ alkene is formed |
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Definition
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Term
| Why does the Hofmann alkene form when a bulky base is used? |
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Definition
| the elimination hydrogens that are the least Sterically hindered (on the least substituted carbon) are attacked |
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Term
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Definition
| the alkene double bond will be formed between the carbon containing the leaving group and the least substituted adjacent carbon; thermodynamically less favored isomer is formed; named after chemist who did experiments on this type of reaction |
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Term
| Before an E2 reaction takes place, bond rotation to an _____ conformation occurs |
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Definition
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Term
| Are E2 reactions stereospecific? |
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Definition
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Term
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Definition
| the treatment of alcohols with mineral acid at elevated temperatures to form alkenes by the loss of water; proceeds by E1 or E2 |
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