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Organic Chemistry Test 3
Odom Test 3 Ochem
77
Organic Chemistry
Undergraduate 2
03/21/2012

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Term
alcohols contain a ___ bonded to an ___
Definition
hydroxyl group (OH); sp3 hybridized Carbon atom
Term
alcohols are classified as ____ based on the number of carbon atoms bonded to the carbon with the OH group
Definition
primary, secondary, or tertiary
Term
Compounds having a hydroxy group on an sp2 hybridized carbon are classified as ___ or ____
Definition
enols or phenols
Term
enols have _____
Definition
an OH group on a carbon of a C-C double bond
Term
phenols have ____
Definition
an OH group on a benzene ring
Term
ethers have ____
Definition
two alkyl groups bonded to an oxygen atom
Term
an ether is ___ if the two alkyl groups are the same, and ___ if they are different
Definition
symmetrical; unsymmetrical
Term
___ are ethers having the oxygen atom in a three member ring.
Definition
epoxides
Term
epoxides are also called ___
Definition
oxiranes
Term
alcohols and ethers have a ___ shape
Definition
bent
Term
the bond angle around the O atom in an alcohol or ether is ___
Definition
109.5
Term
the COC bond angle of an epoxide must be ___
Definition
60 degrees
Term
epoxides have ____, making them ____
Definition
angle strain; much more reactive than other ethers
Term
alcohols are capable of ____ bonding
Definition
intermolecular hydrogen bonding
Term
Increasing the number of R groups around the Carbon atom bearing the OH group, ______
Definition
decreases the ability to hydrogen bond
Term
for compounds of comparable molecular weight, the ___ the intermolecular forces, the ___ the bp or mp
Definition
stronger; higher
Term
BP's ___ as the extent of hydrogen bonding ____
Definition
increase; increase
Term
alcohols, ethers, and epoxides having less than or equal to 5 C's are _____
Definition
H2O soluble because they each have an oxygen atom capable of hydrogen bonding to the H2O
Term
alcohols, ethers, and epoxides having greater than 5 C's are _____
Definition
H2O insoluble because the nonpolar alkyl portion is to large to dissolve in H2O
Term
ranking of intermolecular foces
Definition
HB>DD>VDW
Term
alcohols, ethers, and epoxides of any size are ___ in organic solvents
Definition
soluble
Term
alcohols and ethers are both common products of ____. They are synthesized from alkyl halides by ___ reactions using strong nucleophiles
Definition
nucleophilic substitution; Sn2
Term
because the mechanism is Sn2, the preferred path uses the _____
Definition
less sterically hindered halide
Term
a ___ nucleophile is needed to synthesize an alcohol, and salts such as NaOH and KOH
Definition
hydroxide
Term
an ____ is needed to make an ether
Definition
alkoxide salt
Term
when an organic compound contains both a hydroxy group and a halogen atom on adjacent carbon atoms, an ______
Definition
intramolecular version of this reaction forms an epoxide
Term
the starting material for the two step sequence of epoxide synthesis is a ____
Definition
halohydrin
Term
-OH is a ___ base, and therefore a ___ leaving group
Definition
strong; poor
Term
for an alcohol to undergo a nucleophilic substitution or elimination reaction, the OH group must be ____; this can be done by reaction with ____
Definition
converted into a better leaving group; acid
Term
the protonation of -OH makes ___, therefore a ___ leaving group
Definition
H2O, good leaving group
Term
___ are formed by beta elimination
Definition
alkenes
Term
___ are formed by nucleophilic substitution
Definition
alkyl halides
Term
ethers do not contain a ____
Definition
good leaving group
Term
removing water from an alcohol is a ___ reaction
Definition
dehydration
Term
dehydration is a ____ reaction, in which the elements of ___ and ___ are removed from the _____
Definition
Beta elimination; OH; H; alpha and beta carbon atoms
Term
dehydration is typically carried out using ____ or ____
Definition
H2SO4 and other strong acids or POCl3
Term
____ alcohols dehydrate more readily
Definition
more substituted
Term
when an alcohol has two or three different beta carbons, dehydration follows the ____
Definition
zaitsev rule
Term
2 and 3 degree alcohols react by the ___ mechanism, whereas 1 degree alcohols react by the ___ mechanism
Definition
E1; E2
Term
The E1 dehydration of 2 and 3 degree alcohols consists of ___ steps
Definition
3
Term
the dehydration of 2 and 3 degree alcohols occurs via the ___ mechanism with an added first step
Definition
E1
Term
the added first step ____
Definition
protonates the OH group to make a good leaving group
Term
with 1 degree alcohols, dehydration follows the ___ mechanism
Definition
E2
Term
a less stable carbocation can rearrange to a more stable carbocation by shift of a ___ or an ____
Definition
hydrogen atom; alkyl group
Term
movement of a hydrogen atom is called a ____
Definition
1,2 hydride shift
Term
movement of an alkyl group is called a ___
Definition
1,2 alkyl shift
Term
1,2 shifts convert a ___ to a ___
Definition
less stable carbocation; more stable carbocation
Term
the more stable carbocation is the more ____
Definition
substituted
Term
rearrangements can occur whenever a ___ is formed as a _____; meaning any ___ or ___ reaction
Definition
carbocation; reactive intermediate; SN1; E1
Term
the reaction of alcohols with ___ is a general method to prepare ____
Definition
HX; 1,2, and 3 degree alkyl halides
Term
___ alcohols usually react more rapidly with HX
Definition
more substituted
Term
methyl and 1 degree ROH form RX by the ___ mechanism
Definition
Sn2
Term
2 degree and 3 degree ROH form RX by the ___ mechanism
Definition
Sn1
Term
the reactivity of hydrogen halides increases with _____
Definition
increasing acidity
Term
Sn2 reaction have ___ at the stereogenic center
Definition
inversion of stereochemistry
Term
Sn1 reactions yield a _____
Definition
racemic mixture
Term
because carbocations are formed in the Sn1 reaction of 2 and 3 degree alcohols with Hx, ____ are possible
Definition
carbocation rearrangements
Term
one degree and two degree alcohols can be converted to alkyl halides using ____ and ____
Definition
SOCl2; PBr3
Term
ROH->RCl with HCL reagent
- useful for ___
- ___ mechanism for 2 and 3 degree ROH; ___ mechanism for CH3OH and 1 degree ROH
Definition
- all ROH
- sn1; sn2
Term
ROH->RCl with SOCl2 reagent
-best for ____
- ___ mechanism
Definition
- ch3oh and 1 and 2 degree ROH
- sn2 mechanism
Term
ROH->RBr with HBr reagent
- useful for ___
- ___ mechanism for 2 and 3 degree ROH; ___ mechanism for CH3OH and 1 degree ROH
Definition
- all ROH
- sn1; sn2
Term
ROH->RBr with PBr3 reagent
-best for ____
- ___ mechanism
Definition
- ch3oh and 1 and 2 degree ROH
- sn2 mechanism
Term
ROH->RI with HI reagent
- useful for ___
- ___ mechanism for 2 and 3 degree ROH; ___ mechanism for CH3OH and 1 degree ROH
Definition
- all ROH
- sn1; sn2
Term
alcohols can also be converted to ____
Definition
alkyl tosylate
Term
an alkyl tosylate is composed of two parts:
Definition
the alkyl group R and the tosyl group (CH3C6H4SO2-)
Term
because alkyl tosylates have good leaving groups, they undergo _____
Definition
both nucleophilic substitution and beta elimination
Term
generally alkyl tosylates are treated with strong nucleophiles and bases, so that the method of sub is ___, and the mechanism of elimination is ___
Definition
sn2; e2
Term
summary of sub and e reactions with alcohols: the OH group is converted into a better leaving group by treatment with ____. The resulting product undergoes ___ depending on reaction conditions
Definition
acid or another reagent; elimination or substitution
Term
ethers can only react with ___ and ___ because they are strong acids with sources of good nucleophiles.
Definition
HBr and HI
Term
when ethers react with HBr or HI, ___ are cleaved and ___ are formed as products.
Definition
both C-O bonds; two alkyl halides
Term
because both C-O bonds are broken, ___ reactions occur
Definition
two successive nucleophilic substitution reactions occur.
Term
the mechanism of either cleavage is ___ or ___ depending on the identity of R
Definition
sn1 or sn2
Term
with a 2 or 3 degree alkyl group bonded to the ether oxygen, the C-O bond is cleaved by the ___ mechanism. with methyl or 1 degree R groups, the CO bond is cleaved by the ___ mechanism
Definition
sn1; sn2
Term
strong nucleophiles that open epoxides occur via the ___ mechanism
Definition
sn2
Term
the nucleophile opens the epoxide ring from the ____
Definition
back side
Term
in an unsymmetrical epoxide, the strong nucleophile attacks the epoxide at the ___
Definition
less substituted carbon atom
Term
with an acid, the nucleophile attacks the epoxide at the ____
Definition
more substituted carbon
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