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Solvents For Semester 1 Final
Solvents for semester 1 Final
37
Organic Chemistry
Undergraduate 1
12/08/2011

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Term
H2O, H2SO4,HgSO4 + alkyne
Definition
-adds the Oxygen to the more substitueded carbon in the alkyne
Term
BH3, followed by H2O, KOH + alkyne
Definition
-Adds the oxygen to the less substituted Carbon of alkyne
Term
Forming an Alkyne.
Definition
Need two leaving groups on the alkyne, then it is also nessisary to use NaNH2 or tBuO- if it is a geminal dihalide, and if it is a vicinal dihalide (meaning the the leaving groups are on different carbons) it is possible to use NaNH2
Term
NaH and NaNH2
Definition

-these two reagents can form ions by pulling terminal Hydrogens off. 

-Forms the acetylide Ion, or any O-

 

Term
H2SO4
Definition
  • A strong acid can porotonate a alkene or an alkyne, which can futher more create a carbocation. 
  • the first Hydrogen on a multiply bond will be on the least substituted Carbon, which forms the most stable carbocation.
  • Usually used as an acid catalyst. 
 
Term
HX + Alkyne
Definition
  • Same as H2SO4 in the way it attacks. 
  • the Cl-  will attack the carbocation of the  alkyne. 
  • there can also be carbocation rearrangement during this step. 
  • this can form Geminal dihalides
Term
X2,CCl4 + Alkyne
Definition
  • this will put the X atom on both ends of the triple bond. 
  • If Cl2 is in excess there will be four Cl's bonded to the original triple bond. 
  • The Cl will form an "epoxide" like bond. This will make the other Cl come in from the backside fo backsided attack. 
Term
H2O, H2SO4 + Alkyne
Definition
  • these two reagents will react with an aklyne to form an enol, and then to go on to form a Keto molecule. 
  • The H will first protonate the the least substituted to the Carbon.
 
Term

H2, Pd/C + alkyne

 

or 

 

H2, Pt/C + alkyne

Definition
  • both of these reactions will send alkynes to alkanes. 
  • they do not stop at the formation of the alkene. 
Term
H2, Lindlars Catalyst + alkyne
Definition
  • this will form the aklene with cis addtion of the Hydrogen atoms
  • stops at the protonation of the first π bond. 
Term
NH3, Na + alkyne
Definition
  • turns alkyne into a trans alkene.
  • stops at the formation of the alkene. 
  • always forms the trans version of the alkyne in the alkene by adding Hydrogen in a anti addition. 
 
Term

1) O3

2) Zn, H2O

Alkyne

Definition
  • forms 3 bonds to O, most of the time in a carboxyl formation. 
  • If it is a terminal carbon however the fromation will be of a carboxyl and a CO2
Term

HX with Alkene

(Hydrohalogenation)

Definition
  • HX with an alkene will for a nonstereospecific bond with H and X adding to either side of the double bond. 
  • the H atom will add first to the least subst. carbon in the double bond, because that means that it will form the most stable Carbocation. 
  • H-X can go to completion. Aka if there are any more -OH's in the molecule it could get rid of them all.
 
Term

H2O, Acid Cat. (H2SO4, TsOH, H3PO4)

(Hydration) 

Definition
  • Along the sames lines of the HX addition. 
  • H- from the Acid Cat. will add to the least substituted Cabon of the double bond, creating the formation of the carbocation, which will then be attacked by the H2O.
Term

ROH, Acid Cat. (H2SO4, H3PO4, TsOH)

Etherfication

Definition
  • H from the acid cat. will first add to the least subst. side of the double bond then the Oxygen of the ROH will add to the carbocation. 
 
Term

X2, CCl4 to an alkene

(Halogenation)

Definition

this will form a "epoxide" like formation where the X atoms have a positive charge. Then the anion of the other X atom will backside attack to break the "Epoxide"

  • anti additon of the Cl's
 
Term

X2, H2O + alkene

(Halohydren) 

Definition
  • forms a anti addition of the X and OH, because there is a X double bond (looking like an epoxide) which has to undergo backsided attack for it to be opened. This causes its anti adition. 
  • First bond (X adds) forms the most stable carbocation. 
  • H2O would be analogeous to a basic epoxide opening, where it would open from the most substituted carbon. 
Term

1)Hg(oAc)2, H2O + alkene

2) NaBH4 

(oxymecration)

Definition
  • adds the Oxygen to the most substituted carbon. 
  • Adds a H atom to the least substituted carbon. which forms the most stable carbocation. 
  • could be good for forming an alcohol that then could be switched directly to a alkyl group via PBr3, or SOCl2, pyr
Term
  1. BH3
  2. H2O2, KOH
+
 
Alkene
(Borohydration/oxydation)
Definition
  • adds OH to the least substituted Carbon atom. 
  • Is syn addition. 
  • adds water to more substitued carbon.
Term

H2,Pd/C or Pt/C + Alkene

(Hydorgenation)

 

Definition
  • adds hydrogen bonds across the double bond
  • cis addition
  • Will add to all of the multiple bonds, till there are no multiple bonds left. 
Term

1)OsO4, NMO

2)NaHSO3,H2O


or


KMnO4, H2O, KOH

 

(Dihydroxylation)

 

Definition
  • Both reagents add OH to the double bond through syn addition
Term

1)9-BBN

2)H2O2, KOH

+

Alkene

Definition
  • more sterically hindered than BH3, making it more likely to put the OH on the less substituted Carbon of the double bond. 
Term
  1. O3
  2. Zn, H2O
Definition
  • Breaks the alkene, which will form then two new C O double bonds. 
Term
TsCl, pyr
Definition
  • reacts with alcohol to make a good -OTs leaving group. 
  • pyr will pull hydrogen off of the alcohol when it has the -OHTs+ Formation. 
Term

DBU

or

DBN

Definition
  • These are both good E2 solvents, whenever there is a good leaving group present. 
  • OH is not a good Leaving group but -OTs is. 
  • E2 happens at 1˚,2˚,3˚ but not Me. 
  • Antiperiplaner formation is enforced
Term
E1 Reactions
Definition
  • E1 reactions invove a good leaving group and a weaker base. 
    • the base shouldnt have a negative sign on it. 
  • Happens at 2˚, 3˚, and often competes with Sn1 reactions
  • Carbocation rearrangement can occur.
  • Very little use because of lack of control.
  • Unimolecular reaction, carbocation can form
Term
E2
Definition
  • E2 reactions occur at 1˚, 2˚ and 3˚ carbocations, that react with a strong base (has a negative charge). 
    • DBU, DBN, RO-, -OH
  • Anti periplaner conf. between LG and βH 
  • Bimolecular reaction means no carbocation is formed.
Term
Sn1
Definition
  • is a unimolecular reaction that happens and 2˚, 3˚ alkyl halides when they are reacted with a weak Nuc.
  • Carbocartion rearrangement can occur (alkyl or hydride shift.)
  • H2O, ROH, or other non negativly charged atoms react the electrophyle after the LG leaves. 
  • Fastest in protic solvent
Term
Sn2
Definition
  • can happen at Me, 1˚, and 2˚ (slowest at 2˚, E2 will dominate at 2˚)
  • Backside attack and inversion.
  • -N3, -CN, NH3, -OH, -OR, are good for these reactions
Term
Acidic Dehydration
Definition
  • H2SO4, TsOH, H3PO4 are used to pull off an H and an OH, to form a double bond. 
  • Similar to a E1. 
  • Carbocation is produced, rearrangement may occur. 
  • only non nucleophilic acids can praticicpate in the acidic dehydration 
  • E1 happens at 2˚ and 3˚ alcohols
  • E2 happens at 1˚ but it is very reactive and unstable. 
 
Term

Basic Dehydration

POCl3, Pyr

Definition
  • Reaction that happens at all alcohols. 
  • the POCl3 attatches to the OH and then the pyr pulls the H off. 
  • Acts like a E2 reaction at all alcohols. 
  • no carbocation formed. 
Term
Alcohol acidic conversion to Alkyl
Definition
  • at methyl and 1˚ this reaction acts like a Sn2
  • at 2˚ and 3˚ alcohols it acts like Sn1
  • H from H-X first protonates the alcohol making it a good leaving group then X- attacks via Sn2(Backside) or Sn1(enatomers are formed). 
Term
ZnCl2
Definition
  • Can change alcohols to Alkyl's of R-Cl
Term
PBr3
Definition
  • Can change alcohols into R-Br via Sn2 at 1˚, 2˚
Term
SOCl2, pyr
Definition
  • Can change aclohols to R-Cl via Sn2 reaction at 1˚ and 2˚. 
Term
ethers with an HX
Definition
  • All bonds to the oxygen will be broken if the as the acid protonates them and then further more the X- will nucleophilicly attack it. 
Term
Epoxide Openings
Definition
  • Acidic Opening (HOCH3) will first protonate the Oxygen (H2SO4, or acid catalyst) then HOCH3 will attack the more substituted carbon atom. 
  • Basic Opening (-OCH3) there will be nucleophilic attack at the least substituted carbon atom and then there is a water work up for the O anion. 
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