Now let's go to halogenation. Halogenation of alkynes is going to be a very similar ordeal where usually what would we expect to get for a halogenation of an alkene? We would expect to get vicinal dihalides. But instead of getting just 2 halogens, I'm going to react this twice, so I would actually expect to get a tetrahalide product. So obviously, that's going to be a whole lot of halogens. Let's see how that works. Well, basically, remember that the way this mechanism looks is that the triple bond or the double bond grabs the X. The X grabs the double bond or the triple bond, the pi bond kicks out the X. So what we wind up getting is we wind up getting a basically a bridge. Okay? And what that bridge looks like is like this. So I'd have X like that and like that. Okay? And then another X comes around and goes to the Markovnikov position and kicks out the X that's on the bridge. So what I'd wind up getting is this original product where I have vicinal dihalides. These are the vicina
10. Addition Reactions
Alkyne Halogenation
10. Addition Reactions
Alkyne Halogenation - Online Tutor, Practice Problems & Exam Prep
What happens when we add X2 instead of HX to an alkyne? We end up with four halogens in our product. Let's see how that works:
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concept
Double halogenation of alkynes.
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General Reaction:
- Product: tetrahalides
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PRACTICE PROBLEMS AND ACTIVITIES (34)
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- Answer Problem 39 , parts a–h, using 2-butyne as the starting material instead of propyne. d. Br2 (2 mol)/CH2...
- Answer Problem 39 , parts a–h, using 2-butyne as the starting material instead of propyne. c. Br2 (1 mol)/CH2...
- What is the major product of the reaction of 1 mol of propyne with each of the following reagents? c. Br2 (1 ...
- In the addition of just 1 mole of bromine to 1 mole of hex-1-yne, should the hex-1-yne be added to a bromine s...
- (••) For the alkynes shows here, show the product(s) expected to form when treated under the following conditi...
- (••) For the alkynes shows here, show the product(s) expected to form when treated under the following conditi...
- (••••) Trans addition is heavily favored for the addition of Br₂ and Cl₂ to alkynes. With chlorination, howe...
- Drawing on what you know about the stereochemistry of alkene addition reactions,a. write the mechanism for the...
- Drawing on what you know about the stereochemistry of alkene addition reactions,b. predict the configuration o...
- Show how hex-1-yne might be converted tod. 1,1,2,2-tetrabromohexane.
- (•) Predict the product(s) that would result when the alkenes shown here are allowed to react under the follow...
- Predict the products you would get when the following alkenes react under the following conditions: (i) H₂SO₄ ...
- (••) For the alkynes shows here, show the product(s) expected to form when treated under the following conditi...
- (••••) In Section 10.8.1, you learned that alkenes react more quickly with electrophiles than do the correspon...
- (••••) α-Pinene is a terpene found in pine trees. Starting from geranyl diphosphate (a terpene), draw the arro...
- Predict the products you would get when the following alkenes react under the following conditions: (i) H₂SO₄ ...
- (•) Predict the product(s) that would result when the alkenes shown here are allowed to react under the follow...
- What stereoisomers are obtained when 2-butyne undergoes each of the following reaction sequences?a. 1. H2/Lind...
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- Draw the mechanism for the following reaction:<IMAGE>
- (•••) When alkynes are treated with water and bromine a bromoketone is produced. Provide a plausible arrow-pus...
- What reagents should be used to carry out the following syntheses?
- What characteristics must the reactant of a stereospecific reaction have?
- Which electrophilic addition reactions a. form a carbocation intermediate? intermediate?
- Which electrophilic addition reactions c. form a three-membered ring
- Which electrophilic addition reactions d. form a five-membered ring intermediate?
- b. What would the yield be if two more steps (each with an 80% yield) were added to the synthesis?
- Predict the products of reaction of pent-1-yne with the following reagents. (d) H2, Pd/BaSO4, quinoline (e) 1...
- What stereoisomers are obtained when 2-butyne undergoes each of the following reaction sequences?c. 1. Cl2/CH2...