Term
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Definition
| compounds that contain one or more halogen atoms |
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Term
A reaction is an oxidation if....
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Definition
if it results in
(a) an increase in the number of bonds between carbon and an element more electronegative than carbon (for example, O, N, a halogen) or
(b) a decrease in the number of bonds between carbon and a less electronegative element (most often H, but also B, Mg, etc.). |
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Term
A reaction is a reduction if it results in |
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Definition
(a) a decrease in the number of bonds between carbon and an element more electronegative than carbon or
(b) an increase in the number of bonds between carbon and a less electronegative element, most frequently H. |
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Term
What are the rules for oxidation state of Carbon? |
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Definition
A bond to H contributes –1 to the oxidation state of C. (The same is true for any atom less electronegative than C.)
A bond to O, N, or halogen contributes +1 (as does a bond to any element more electronegative than C.)
A bond to C contributes 0. |
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Term
| If the oxidation level of carbon (sum of oxidation states) increases, the reaction is an...... |
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Definition
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Term
| If the oxidation number of a carbon decreases in a reaction the reaction is an..... |
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Definition
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Term
| When naming alkyl halides you number the carbons of the parent chain at the end nearer the first substituent of a alkyl or halo? |
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Definition
| Either or..if the first sub. is a alkyl or halo you start numbering from whichever is first |
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Term
| If two substituents are at the same distance from either end you must..... |
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Definition
| *number in alphabetical order |
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Term
Radical Halogenation of alkanes is not a good method of producing alkyl halide because..... |
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Definition
| a mixture of products is obtained |
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Term
| What is an allylic position? |
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Definition
It is the position NEAR a double bond.
[image]
* = allylic positions |
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Term
| NBS in the presense of light (hv) creates an alkyl halide from a alkene by.. |
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Definition
addition of Br at the allylic position
*occurs by radical chain reaction
*Br radical abstracts an allylic hydrogen forming a allyic radical AND HBR
*HB2 then reacts with NBS to form Br2 which reacts with allylic radical & Br radical
(PAGE 284) |
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Term
| Why does bromination with NBS react at the allylic postion? |
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Definition
Due to bond dissociation energies.
*Allylic(370 kj/mol) has lower bond strength then alkyl [CH3 sp3](410 kj/mol) and vinylic[double bonded C sp2] (465 kj/mol)
*Therefore allylic radicals are more stable and favorable |
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Term
Which order of stability is this?
Vinylic<methyl<primary<secondary<tertiary<allylic |
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Definition
in order from least to greatest stability |
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Term
| Allylic Radicals are symmetrical so they have 2 resonance forms which consist of.... |
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Definition
1. with unpaired electron on the left and double bond on right
2. with unpaired electron on right and double bond on left
[image] |
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Term
The greater the number of resonance structures an allylic radical can have .............. |
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Definition
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Term
| A allylic radicals are stable because the electrons are delocalized which means.. |
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Definition
| electrons are spread out over extended Pi orbital rather then localized at one site. |
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Term
| allylic bromination of unsymmetrical alkenes gives a mixture product..which end is most favored? |
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Definition
Primary End
(C bonded to one other C and 2 H) |
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Term
| Preparing alkyl halides from alcohol work best with Primary, secondary, or tertiary alcohols? |
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Definition
Tertiary Alcohols
(primary and secondary act more slowly) |
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Term
| OH on tertiary Carbon with react with what to give a alkyl halide? |
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Definition
H-X & Ether at 0 degrees celsius
(Halogen replaces the OH) |
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Term
| What two reagents interact with primary and secondary alcohols? What to they do? |
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Definition
SOCl2 & pyridine (replaces OH with Cl)
PBr3 & Ether 35 deg C (replaces OH with Br)
[(Ch3Ch2)2NSF3] HF & Pyridine(replaces OH with F)
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Term
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Definition
the products of alkyl halides reacting with Magnesium Metal in Ether or THF
*aka alkylmagnesium halides
* example of organometallic compound b/c of carbon metal bond |
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Term
What are the products of?
CH3CH2CH2Br----->Mg/ether------->H20 |
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Definition
1.CH3CH2CH2MgBr (Mg goes between C and X)
2.CH3CH2CH3 (Water destroys Mg) |
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Term
| Grignard Reagent can also be used to convert an alkyl halide to an... |
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Definition
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Term
Alkyllithium Reagents created by |
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Definition
| alkylhalide reacting with lithium metal and are very strong nucleophiles and bases |
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Term
What is the product?
CH3CH2CH2CH2Br----->2 Li |
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Definition
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Term
| What are Gilman Reagents? |
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Definition
| When alkyllithiums react with copper(I)Iodide in ether solvent to form lithium dialkylcopper (gilman reagent) |
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