Term
*Close Observation of Free-Radical Addition of HBr to Alkenes*
Initiaiton Step: Free radicals generated from the __________ react with __________ to form bromine radicals.
The __________ radical lacks an octet of electrons in its valence shell, making it electron-deficient and __________. It adds to a double bond, forming a new __________ radical with the odd electron on a carbon atom.
This __________ radical reacts with an __________ molecule to form a C-H bond and generate another __________ radical.
The regenerated __________ radical reacts with another molecule of the alkene, continuing the chain reaction. Both of the propogaiton steps are moderately __________, allowing them to proceed faster than the __________ steps.
Each __________ step begins with one free radican and ends with another; thus the number of free radicals in the reaction is __________. |
|
Definition
1) Peroxide
2) HBr
3) Bromine
4) Electrophilic
5) Free
6) Free
7) HBr
8) Bromine
9) Bromine
10) Exothermic
11) Termination
12) Propogation
13) Constant |
|
|
Term
In the radical addition of HBr to unsymmetrical alkenes, the __________ (the bromine radical) adds to the (more/less) substitued carbon to give the (more/less) stable free radical.
The __________ formed reacts with HBr to give the __________-__________ product, in which case a hydrogen atom has added to the (more/less) substituted end of the double bond: the end that started with (more/fewer) hydrogens. |
|
Definition
1) Electrophile
2) Less
3) More
4) Intermediate
5) Anti-Markonikov
6) Less
7) Fewer |
|
|
Term
According to Markovnikov's rule, an electrophile iwll add to the (more/less) substituted end of a double bond to give the (more/less) stable intermediate, either a __________ or a __________ __________.
-In the ionic reaciton, the electrophile is __________.
-In the peroxide-catalyzed free-radical reaction, the electrophile is __________. |
|
Definition
1) Less
2) More
3) Carbocation
4) Free radical
5) H+
6) Bromine radical |
|
|
Term
The stability of radicals follows the trend:
__________ > __________ > __________ > __________>
A __________ adds to a double bond to give the most stable radical in the intermediate. |
|
Definition
1) 3° > 2° > 1° > CH3X
2) Radical |
|
|
Term
| If just a tiny bit of __________ is present, a mixture of Markovnikov and anti-Markovnikov products result. |
|
Definition
|
|
Term
| If an apperciable amount of __________ is present, the radical chain reaction is so much faster than the uncatalyzed ionic reaciton that only the __________-__________ product is observed |
|
Definition
1) Peroxide
2) anti-Markovnikov |
|
|
Term
| The reversal of orientation in the presence of peroxides is called the __________ __________; it occurs only with the addition of __________ to alkenes. |
|
Definition
|
|
Term
| The peroxide effect is not seen with __________ because the reaction of an alkyl radical with __________ is strongly __________. |
|
Definition
1) HCl
2) HCl
3) Endothermic |
|
|
Term
| If a reaciton is strongly __________, than the products are favored. |
|
Definition
|
|
Term
| If a reaction is strongly __________, the reactants are favored. |
|
Definition
|
|
Term
| The peroxide efects is not observed with __________ because the reaction of an __________ atom with an alkene is strongly __________. |
|
Definition
1) HI
2) Iodine
3) Endothermic |
|
|
Term
| An alkene may react with water in the presence of a strongly __________ catalyst to form an __________. |
|
Definition
|
|
Term
| The __________ reaction is one in which a hydrogen atom is added to one carbon and a hydroxyl group to the other; it occurs oly in the presence of a strongly __________ catalyst. |
|
Definition
|
|
Term
| __________ of an alkene is the reverse of the dehydration of alcohols. |
|
Definition
|
|
Term
| Hydration of an alkene is the reverse of the __________ of alcohols. |
|
Definition
|
|
Term
| To dehydrate an alcohol, a concentrated dehydrating acid (such as __________ or __________) is used to drive the equilibrium to favor the __________. |
|
Definition
|
|
Term
| Hydration of an alkene is accomplished by adding excess __________ to drive the equilibrium toward the __________. |
|
Definition
|
|
Term
| The __________ __________ __________ __________ states that a forward reaction and a reverse reaction taking place under the same conditions (as in an __________) must follow the same reaction pathway in microscopic detail. |
|
Definition
1) Principle of microscopic reversibility
2) Equilibrium |
|
|
Term
| For a hydration and dehydration reaction, the lowest-energy __________ __________ and __________ are the same as they both follow the same reaction pathway. |
|
Definition
1) Transition states
2) Intermediates |
|
|
Term
| According to the __________ __________ __________ __________, we can write the __________ mechanism by reversing the order of the steps of the dehydration mechanism. |
|
Definition
1) Principle of microscopic reversibility
2) Hydration |
|
|
Term
*Acid-Catalyzed Hydration of an Alkene*
Step 1: __________ of the double bond forms a carbocation.
Step 2: __________ attack by water gives a protonated __________.
Step 3: __________ gives the alcohol. |
|
Definition
1) Protonation
2) Nucleophilic
3) Alcohol
4) Deprotonation |
|
|
Term
| Like the addition of hydrogen halides, hydration is __________: it follows __________ __________, giving a product in which the new hydrogen has added to the less substituted end of the double bond to produce the more stable (and substituted) __________. |
|
Definition
1) Regioselective
2) Markonikov's Rule
3) Carbocation |
|
|
Term
| Like other reactions that involve carbocation intermediates, hydration may take place with __________. |
|
Definition
|
|
Term
| Any reaction that features a __________ can generally undergo rearrangement. |
|
Definition
|
|
Term
| Many alkenes do not easily undergo __________ in aqueous acid: some alkenes are nearly __________ in aqueous acid, other undergo side reactions such as __________ and __________, and others __________ under strongly acidic conditions. |
|
Definition
1) Hydration
2) Insoluble
3) Rearrangement
4) Polymerization
5) Charr |
|
|
Term
| In many alkene hydration reactions, the overall equilibrium will favor the __________ over the __________. |
|
Definition
|
|
Term
| __________-__________ is another method for converting alkenes to __________ with Markonikov orientation. |
|
Definition
1) Oxymercuration-demercuration
2) Alcohols |
|
|
Term
| __________-__________ reactions work well with many alkenes that do not easily undergo direct __________, and the reactions often take place under milder conditions. |
|
Definition
1) Oxymecuration-demercuration
2) Hydration |
|
|
Term
| In oxymercuration-demercuration reactions, no free __________ is formed, so there is no opportunity for __________ or __________ of alkenes. |
|
Definition
1) Carbocation
2) Rearrangements
3) Polymerization |
|
|
Term
The reagent for oxymercuration-demercuration reactions is __________ __________ Hg(OCOCH3)2, abbreviated Hg(OAc)2.
-There are several theories for how this reagent acts as an __________; the most simple one is that mercuric acetate __________ slightly to form a positively charged __________ species, Hg+(OAc). |
|
Definition
1) Mercuric acetate
2) Electrophile
3) Dissociates
4) Mercury |
|
|
Term
In the oxymercuration-demercuration reactions, __________ involves an electrophilic attack on the double bond by the positively charged __________ species. The product is a __________ __________, an organometallic cation containing a three-membered ring.
In the second step, water from the solvent attacks the mercurinium ion to give (after __________) an __________.
A subsequent reaction is __________ which removes the mercury. __________ __________ (NaBH4, a reducing agent) then replaces the mercuric acetate fragment with a hydrogen atom. |
|
Definition
1) Oxymercuration
2) Mercury
3) Mercurinium ion
4) Deprotonation
5) Alcohol
6) Demercuration
7) Sodium borohydride |
|
|
Term
*Oxymercuration of an Alkene*
Step 1: Electrophilic attack forms a __________ __________.
Step 2: __________ opens the ring to give an organomercurial __________.
Step 3: __________ replaces the mercuric fragment with hydrogen to give the alcohol. |
|
Definition
1) Mercurinium ion
2) Water
3) Alcohol
4) Demercuration |
|
|
Term
Oxymercuration-demercuarion of an __________ alkene generally gives __________ orientation of addition, as can be seen in the oxymercuration of propene.
The mercurinium ion has a considerable amount of positive charge on both of its __________ atoms, but there is a greater positive charge on the (less/more) substituted carbon atom, where it is more stable.
Attack by __________ occurs on the most __________ (substituted) carbon, giving __________ orientation. As a result, the electrophile - +Hg(OAc) - remains bonded to the (less/more) substituted end of the double bond. |
|
Definition
1) Unsymmetrical
2) Markovnikov
3) Carbon
4) More
5) Water
6) Electrophilic
7) Markonikov
8) Less |
|
|
Term
| Oxymercuration-demercuration reliably adds __________ across the double bond of an alkene with __________ orientation and without __________. |
|
Definition
1) Water
2) Markovnikov
3) Rearrangement |
|
|
Term
| Of the methods available for __________ hydration of alkenes, __________-__________ is most commonly used in the laboratory as it gives greater yields than direct acid-catalyzed hydration, avoids the possibility of __________, and does not involve harsh conditions. |
|
Definition
1) Markovnikov
2) Oxymercuration-demercuration
3) Rearrangements |
|
|
Term
When mercuration takes place in an alcohol solvent, __________ serves as the nucleophile to attack the __________ ion.
The resulting product contains an __________ group; this reaction is known as a __________-__________ |
|
Definition
1) Alcohol
2) Mercurinium
3) Alkoxy
4) Alkoxymercuration-demercuration |
|
|
Term
| __________-__________ is a reaction which converts alkenes to ethers by adding an alcohol across the double bond of the alkene. |
|
Definition
| 1) Alkoxymercuration-demercuration |
|
|
Term
In an alkoxymercuration-demercuration reaction, an alkene reacts to form a __________ ion that is attacked by the nucleophilic solvent.
Attack by an __________ solvent gives an organomercurial ether that can be reduced to an __________.
The solvent attacks the __________ ion at the (less/more) substituted end of the double bond (where there is a greater __________ charge) giving __________ orientation of addition.
The Hg(OAc) group appears at the (less/more) substituted end of the double bond.
Reduction gives the __________ product, with hydrogen at the (less/more) substituted end of the double bond. |
|
Definition
1) Mercurinium
2) Alcohol
3) Ether
4) Mercurinium
5) More
6) Positive
7) Markonikov
8) Less
9) Markovnikov
10) Less |
|
|
Term
| In 1979, H.C. Brown of Purdue University discovered that __________ adds to alkenes with __________-__________ orientation to form alkylboranes which can be oxidized to give anti-Markovnikov __________. |
|
Definition
1) Diboranes
2) anti-Markovnikov
3) Alcohols |
|
|
Term
__________ (B2H6) is a dimer composed of two molecules of borane (BH3).
The bonding in __________ is unconventional, using three-centered (banana-shaped) bonds with __________ in the middle of them.
__________ is in equilibrium with a small amount of borane (BH3), a strong __________ __________ with only six valence electrons. |
|
Definition
1) Diborane
2) Diborane
3) Protons
4) Diborane
5) Lewis acid |
|
|
Term
__________ is an inconvenient reagent; it is toxic, flammable, and an explosive gas. It is more easily used as a complex with __________, a cyclic ether.
__________ reacts like diborane, yet the solution is easily measured and transferred. |
|
Definition
|
|
Term
The __________*__________ is the form of borane commonly used in organic reactions.
__________ adds to the double bond of an alkene to give alkylborane.
Basic __________ __________ oxidizes the alkylborane to an alcohol.
In effect, __________-__________ are reactions which convert alkenes to alcohols by adding water across the double bond, with __________-__________ orientation. |
|
Definition
1) BH3*THF
2) BH3
3) Hydrogen peroxide
4) Hydroboration-oxidation
5) Anti-Markovnikov |
|
|
Term
*Mechanism of Hydroboration*
Borane is an electron-deficient compound, having only __________ valence electrons (which causes it to lack an octet.) Acquiring an __________ is the driving force for the unusual bonding structures ("banana" bonds, for example) found in __________ compounds.
As an electron-deficient compound, BH3 is a strong __________ capable of adding to a double bond; this reaction is known as __________ of the double bond and is thought to occur in one step with the __________ atom adding to the (less/more) substituted end of the double bond. |
|
Definition
1) Six
2) Octet
3) Boron
4) Electrophile
5) Hydroboration
6) Boron
7) Less |
|
|
Term
*Mechanism of Hydroboration*
In the transition state, the electrophilic __________ atom withdraws electrons from the __________ bond, and the carbon at the other end of the double bond acquires a partial __________ charge. This partial charge is (less/more) stable on the (less/more) substituted carbon atom.
The product of the reaction shows __________ bonded to the less substituted end of the double bond and the __________ bonded to the more substituted end.
__________ __________ also favors boron adding to the less hindered, less substituted end of the double bond. |
|
Definition
1) Boron
2) Pi
3) Positive
4) More
5) More
6) Boron
7) Hydrogen
8) Steric hindrance |
|
|
Term
*Hydroboration of an Alkene*
__________ adds to the double bond in a single step.
__________ adds to the less hindered / substituted carbon as __________ adds to the more substituted carbon. |
|
Definition
1) Boron
2) Boron
3) Hydrogen |
|
|
Term
| During hydroboration of alkenes, the boron atom is removed by __________ in which aqueous __________ __________ and __________ __________ (HOOH) is used to replace the boron atom with a __________ group. |
|
Definition
1) Oxidation
2) Sodium hydroxide
3) Hydrogen peroxide |
|
|
Term
| The hydration of an alkene by __________-__________ is another example of a reaction that does not follow the original statement of __________ __________ (the product is anti-Markovnikov), but still follows our understanding of the reasoning behind Markovnikov's rule: the electrophilic __________ atom adds to the less substituted end of the double bond, placing the positive charge (and __________ atom) at the more substituted end. |
|
Definition
1) Hydroboration-oxidation
2) Markovnikov's rule
3) Boron
4) Hydrogen |
|
|
Term
It is important to note that 3 moles of an alkene can react with each mole of __________; each B-H bond in the molecule can add across the double bond of an alkene.
The first addition forms an __________, the second a __________, and the third a __________. |
|
Definition
1) BH3
2) Alkylborane
3) Dialkylborane
4) Trialkylborane |
|
|
Term
__________ react as predicted, and oxidize to give __________-__________ alcohols.
Overall they are quite bulky, further reinforcing the preference of the __________ atom to add to the less hindered carbon atom of the double bond. |
|
Definition
1) Trialkylboranes
2) Anti-Markonikov
3) Boron |
|
|
Term
| In a hydroboration-oxidation reaction, the simultaneous addition of boron and hydrogen to the double bond leads to a __________ __________: boron and hydrogen add across the double bond on the same side of the molecule (if they added to opposite sides of the molecule, the process would be an __________ __________). |
|
Definition
1) Syn addition
2) Anti addition |
|
|
Term
Stereochemistry of hydroboration-oxidation of 1-methylcyclopentene:
Step 1: Boron and hydrogen add to the same face of the double bond (__________) to form a __________.
Step 2: __________ of the trialkylborane replaces boron with a __________ group in the same stereochemical position; the product is trans-2-methylcyclopentanol.
A __________ mixture is expected because a __________ product is formed from achiral reagents.
It is important to note that the second step (oxidation of the borane to the __________) takes place with __________ of configuration. __________ ion adds to the borane, causing the alkyl group to migrate from boron to oxygen. __________ of the borate ester gives the alcohol. |
|
Definition
1) Syn
2) Trialkylborane
3) Oxidation
4) Hydroxyl
5) Racemic
6) Chiral
7) Alcohol
8) Retention
9) Hydroperoxide
10) Hydrolysis |
|
|
Term
| __________ of alkenes is another example of a __________ __________ in which different stereoisomers of the starting compound react to give different stereoisomers of the product. |
|
Definition
| 1) Stereospecific reaction |
|
|
Term
| Halogens add to alkenes to form __________ __________. |
|
Definition
|
|
Term
Mechanism of Halogen Addition:
A halogen molecule (Br2, Cl2, or I2) is __________; a nucleophile can react with it, displacing a halide ion. |
|
Definition
1) Halogen
2) Electrophile |
|
|
Term
Mechanism of Halogen Addition:
In the reaction of an alkene with a bromine molecule, the __________ electrons of the alkene attack the __________ molecule, expelling the __________ ion. A __________ __________ results, containing a three-membered ring with a positive charge on the __________ atom.
The bromonium ion is similar in structure to the __________ ion discussed earlier.
Similar reaction with other halogens form other __________ ions, including a __________ ion, a __________ ion, and a __________ ion. |
|
Definition
1) Pi
2) Bromine
3) Bromide
4) Bromonium ion
5) Bromine
6) Mercurinium
7) Halonium
8) Chloronium
9) Bromonium
10) Iodonium |
|
|
Term
Unlike a normal carbocation, all the atom is a __________ ion have filled octets.
However, the three-membered ring has considerable __________ __________, combined with a __________ charge on an __________ halogen atom, making the halonium ion strongly __________.
Attack by a __________, such as a __________ ion, opens the halonium ion to produce a stable product. |
|
Definition
1) Halonium
2) Ring strain
3) Positive
4) Electronegative
5) Electrophilic
6) Nucleophile
7) Halide |
|
|
Term
*Addition of Halogens to Alkenes*
Step 1: __________ attack forms a halonium ion.
Step 2: The __________ ion opens the halonium ion. |
|
Definition
1) Electrophilic
2) Halide |
|
|
Term
| __________ and __________ most commonly add to alkenes through the halonium ion mechanism. |
|
Definition
|
|
Term
In halonium mechanisms, __________ is used less frequently because diiodie products decompose easily.
Any solvents used must be inert to the halogens; __________ __________ (CH2CL2), __________(CHCL3) and __________ __________ (CCl4) are the most frequent choices. |
|
Definition
1) Iodination
2) Methylene chloride
3) Chloroform
4) Carbon tetrachloride |
|
|
Term
| The addition of __________ has been used as a simple chemical test for the presence of __________ double bonds: a solution of bromine in __________ __________ is a clear, deep red color. When added to an alkene, the red __________ color disappears and the solution becomes clear and colorless. |
|
Definition
1) Bromine
2) Olefinic
3) Carbon tetrachloride
4) Bromine |
|
|
Term
| The addition of bromine to cyclopenetne is a stereospecific __________ __________. |
|
Definition
|
|
Term
Anti stereochemistry results from the __________ __________ mechanism.
When a nucleophile attacks a __________ ion, it must do so from the __________ __________, in a manner similar to the SN2 displacement; this ensures anti stereochemistry of addition. |
|
Definition
1) Bromonium ion
2) Halonium
3) Back side |
|
|
Term
| Halogen addition is another example of a __________ __________, in which different stereoisomers of the starting material give different stereoisomers of the product. |
|
Definition
| 1) Stereospecific reaction |
|
|
Term
A __________ is an alcohol with a halogen on the adjacent carbon atom.
In the presence of __________, halogens add to alkenes to form halohydrins. The electrophilic __________ adds to the alkene to give a __________ ion, which is also electrophilic.
__________ acts as a nucleophile to open the halonium ion and form the __________. |
|
Definition
1) Halohydrin
2) Water
3) Halogen
4) Halonium
5) Water
6) Halohydrin |
|
|
Term
*Formation of Halohydrins*
Step 1: Electrophilic attack forms a __________ ion.
Step 2: __________ opens the halonium ion; deprotonation gives the __________. |
|
Definition
1) Halonium
2) Water
3) Halohydrin |
|
|
Term
Formation of Halohydrins:
1. When halogentaiton takes place with no __________ or with an inert solvent such as __________ __________ or __________, only the __________ ion is available as a nucleophile to attack the halonium ion; the result is a __________.
2. When an alkene reacts with a halogen in the presence of a nucleophilic solvent such as __________, a __________ molecule is the most likely nucleophile to attack the halonium ion.
3. When a water molecule attacks the halonium ion, the final product is a __________, with a __________ on one carbon atom and a __________ __________ on the adjacent carbon.
Thus, the product can either be a __________, __________, or an __________, depending on the halogen. |
|
Definition
1A) Solvent
1B) Carbon tetrachloride
1C) Chloroform
1D) Halide
1E) Dihalide
2A) Water
2B) Solvent
3A) Halohydrin
3B) Halide
3C) Hydroxyl
4) Chlorohydrin
5) Bromohydrin
6) Iodohydrin |
|
|
Term
Stereochemistry of Halohydrin Formation:
Since the mechanism involves a __________ ion, the stereochemistry of addition is __________, as in halogenation. |
|
Definition
|
|
Term
Orientation of Halohydrin Formation:
Even when a __________ ion is involved rather than a carbocation, the extended version of Markovnikov's rule applies to __________ formation.
When propene reacts with chlorine water, the major product as the electrophile (the __________ atom) bonded to the (less/more) substituted carbon of the double bond. The nucleophile (the __________ group) is bonded to the (less/more) substituted carbon. |
|
Definition
|
|
Term
The Markovnikov orientation observed in halohydrin formation is explained by the structure of the __________ ion intermediate.
The two carbon atoms bonded to the halogen have partial __________ charges, with a larger charge (and a [weaker/stronger] bond to the halogen) on the (less/more) substituted carbon atom.
The nucleophile (__________) attacks this (less/more) substituted, (less/more) electrophilic carbon atom.
The result is both __________ stereochemistry and __________ orientaiton. |
|
Definition
1) Halonium
2) Positive
3) Weaker
4) More
5) Water
6) More
7) More
8) Anti
9) Markovnikov |
|
|
Term
| The __________ ion mechanism is similar to the mercurinium ion mechanism for __________ of an alkene, and both give __________ orientation. |
|
Definition
1) Halonium
2) Oxymercuration-demercuraiton
3) Markovnikov |
|
|
Term
Hydrogenation of an alkene is formally a __________ with H2 adding across the double bond to produce an __________.
The process usually requires a catalyst containing __________, __________, or __________. |
|
Definition
1) Reduction
2) Alkane
3) Pt
4) Pd
5) Ni |
|
|
Term
Catalytic Hydrogenation:
For most alkenes, __________ takes place at room temperature, using hydrogen gas and atmospheric pressure.
The alkene is usually dissolved in an __________, an __________, or __________ __________.
A small amount of __________, __________, or __________ catalyst is added, and the container is shaken or stirred as the reaction proceeds.
__________ actually takes place at the surface of the metal, where the liquid solution of the alkene comes into contact with __________ and the catalyst. |
|
Definition
1) Hydration
2) Alcohol
3) Alkene
4) Acetic acid
5) Platinum
6) Palladium
7) Nickel
8) Hydrogenation
9) Hydrogen |
|
|
Term
In catalytic hydrogenation, __________ gas is absorbed on the surface of the metal catalysts (__________, __________, or __________) and the catalyst weakens the __________ bond.
In fact, if H2 or D2 are mixed in the presence of a platinum catalyst, the two isotopes quickly scramble to produce a random mixture of __________, __________, and __________ (no scrambling occurs in the absence of the __________). |
|
Definition
1) Hydrogen
2) Platinum
3) Palladium
4) Nickel
5) Hydrogen-Hydrogen (H-H)
6) HD
7) H2
8) D2
9) Catalyst |
|
|
Term
| Catalytic hydrogenation is an example of __________ __________, because the solid catalyst is in a different phase from the reactant solution. |
|
Definition
| 1) Heterogeneous catalysis |
|
|
Term
| __________ __________ involves reactants and catalyst in the same phase, as in the acid-catalyzed dehydration of an alcohol. |
|
Definition
|
|
Term
In catalytic hydrogenation, because the two __________ atoms add from a solid surface, they add with __________ stereochemistry.
Hydrogen inserts into the __________ bond, and the product is freed from the catalyst.
Both __________ atoms add to the face of the double bond that is complexed with the catalyst. |
|
Definition
|
|
Term
Soluble homogenous catalysts, such as __________ catalyst, also causes catalytic hydrogenation of carbon-carbon double bonds.
__________ catalyst is not chiral, but its tripheylphosphine (PPh3) ligands can be replaced by __________ ligands to give chiral catalysts that are capable of converting optically __________ starting materials to optically __________ products; the process is called __________ __________ or __________ __________. |
|
Definition
1) Wilkinson's
2) Wilkinson's
3) Chiral
4) Inactive
5) Active
6) Asymmetric induction
7) Enantioselective synthesis |
|
|
Term
| The process of converting optically inactive starting materials to optically active products is known as __________ __________ or __________ __________. |
|
Definition
1) Asymmetric induction
2) Enantioselective synthesis |
|
|
Term
__________(:CH2) is the simplest of the __________: uncharged, reactive intermediates that have a __________ atom with two bonds and two nonbonding electrons.
Like __________, methylene is a potent electrophile because it has an unfilled octet.
Methylene adds to the electron-rich __________ bond of an alkene to form a __________. |
|
Definition
1) Methylene
2) Carbenes
3) Carbon
4) Borane
5) Pi
6) Cyclopropane |
|
|
Term
Two difficulties arise when adding diazomethane to double bonds:
1. It is extremely toxic and __________.
2. __________ generated from diazomethhane is so reactive that it inserts into __________ bonds as well as __________ bonds. |
|
Definition
1) Explosive
2) Methylene
3) C-H
4) C=C |
|
|
Term
| Two DuPont chemists discovered a reagent that converts alkenes to __________ in better yields than diazomethane with fewer side reactions; the __________-__________ reaction - named in their honor - is one of the best methods for creating __________. |
|
Definition
1) Cyclopropane
2) Simmons-Smith
3) Cyclopropanes |
|
|
Term
The Simmons-Smith reagent is made by adding __________ __________ to the "zinc-copper couple" (__________ dust that has been activated with an impurity of __________).
The reagent probably resembles __________ __________ __________ ICH2ZnI, which is a __________. |
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Definition
1) Methylene iodide
2) Zinc
3) Copper
4) Iodomethyl zinc iodide
5) Carbenoid |
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Term
| Reagents such as the __________-__________ reagent (ICH2ZnI) are called __________ because they react very similar to carbenes but do not actually contain a divalent __________ atom. |
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Definition
1) Simmons-Smith
2) Carbenoid
3) Carbon |
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Term
Carbenes are also formed by reactions of __________ compounds with __________.
If a carbon atom has at least one __________ and enough halogen atoms to make the hydrogen slightly __________, it may be possible to form a carbene. |
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Definition
1) Halogenated
2) Bases
3) Hydrogen
4) Acidic |
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Term
| A dehydration in which a hydrogen and halogen atom are lost from the same carbon atom is known as a __________ __________ (not as common). |
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Definition
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Term
| A dehydration in which a hydrogen and halogen atom are lost from adjacent carbon atoms is known as a __________ __________. |
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Definition
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Term
| The products of cycloproponations (retain/invert) the cis or trans stereochemistry of the __________. |
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Definition
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Term
| Oxidation usually refers to reactions that form __________-__________ bonds (__________ are oxidizing agents, and the addition of a halogen molecule across a double bond is formally an __________ as well). |
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Definition
1) Carbon-oxygen
2) Halogens
3) Oxidation |
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Term
| An __________ is a three-membered cyclic ether, also called an __________. |
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Definition
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Term
| __________ are valuable synthetic intermediates used for converting alkenes to a variety of other functional groups. |
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Definition
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Term
| An alkene is converted to an epoxide by a __________, a carboxylic acid that has an extra __________ atom in a -O-O- (__________) linkage. |
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Definition
1) Peroxyacid
2) Oxygen
3) Peroxy |
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Term
The __________ of an alkene is clearly an oxidation, since an __________ atom is added.
__________ are highly selective oxidizing agents. |
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Definition
1) Epoxidation
2) Oxygen
3) Peroxyacids |
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Term
A __________ epoxidizes an alkene by a __________ electrophilic reaction where several bonds are broken and formed at the same time.
Starting with the alkene and the peroxyacid, a one-step reaction gives the __________ and the __________ directly, without any intermediates. |
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Definition
1) Peroxyacid
2) Concerted
3) Epoxide
4) Acid |
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Term
*Mechanism 8-9: Epoxidation of Alkenes*
Step 1: __________ epoxidize alkenes in a one-step (__________) process. |
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Definition
1) Peroxyacids
2) Concerted |
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Term
| Since epoxidation reactions take place in one step (__________), there is no opportunity for the alkene molecule to rotate and change its __________ or __________ geometry; the __________ retains whatever stereochemistry is present in the alkene. |
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Definition
1) Concerted
2) Cis
3) Trans
4) Epoxide |
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