All Matches

Solution Library

Expert Answer

Textbooks

Search Textbook questions, tutors and Books

Oops, something went wrong!

Change your search query and then try again

Result Not Found

Books FREE
Tutors
Study Help
Hire a Tutor
AI Study Help New

Search
Sign In
Register

study help
chemistry
organic chemistry

Questions and Answers of Organic Chemistry

The 1, 2 adduct and the 1, 4 adduct formed by reaction of HBr with 1, 3-butadiene are in equilibrium at 40°C. Propose a mechanism by which the inter conversion of products takes place.
Why do you suppose 1, 4 adducts of 1, 3-butadiene are generally more stable than 1, 2 adducts?
Predict the product of the following Diels-Alderreaction:
Which of the following alkenes would you expect to be good Diels-Alder dienophile?s?
Which of the following dienes have an s-cis conformation, and which have an s-trans conformation? Of the s-trans dienes, which can readily rotate tos-cis?
Predict the product of the following Diels?Alder reaction:
Draw a segment of the polymer that might be prepared from 2-phenyl-1, 3-butadiene.
Show the mechanism of the acid-catalyzed polymerization of 1, 3-hutadiene.
Calculate the energy range of electromagnetic radiation in the UV region of the spectrum from 200 to 400 nm. How does this value compare with the values calculated previously for JR and NMR
A knowledge of molar absorptivities is particularly important in biochemistry, where UV spectroscopy can provide an extremely sensitive method of analysis. For example, imagine that you wanted to
Which of the following compounds would you expect to show ultraviolet absorptions in the 200 to 400nmrange?
Show the structures of all possible adducts of the following diene with 1 equivalent ofHC1:
Show the product of the Diels?Alder reaction of the following diene with 3-buten-2-one, H2C = CHCOCH3. Make sure you show the full stereochemistry of the reaction product.
The following diene does not undergo Diels?Alder reactions. Explain.
The following model is that of an allylic carbocation intermediate formed by Protonation of a conjugated diene with HBr. Show the structure of the diene and the structures of the final
Give IUPAC names for the followingcompounds:
What product(s) would you expect to obtain from reaction of 1, 3-cyclo-hexadiene with each of the following?(a) 1 mol Br2 in CH2C12(b) O3 followed by Zn(c) 1 mol HCI in ether(d) 1 mol DCl in ether(e)
Draw and name the six possible diene isomers of formula C5H8. Which of the six are conjugated dienes?
Treatment of 3, 4-dibromohexane with strong base leads to loss of 2 equivalents of HBr and formation of a product with formula C6H10. Three products are possible. Name each of the three, and tell how
Electrophilic addition of Br2 to isoprene (2-methyl-1, 3-hutadiene) yields the following product mixture: Of the 1, 2-addition products, explain why 3, 4-dibromo-3-methyl-1-butene (21 %) predominates
Propose a structure for a conjugated diene that gives the same product from both 1, 2- and 1, 4-addition of HBr.
Draw the possible products resulting from addition of 1 equivalent of HC1 to l-phenyl-1, 3-hutadiene. Which would you expect to predominate, andwhy?
2, 3-Di-tert-butyl-1, 3-butadiene does not undergo Diels?Alder reactions. Explain.
Diene polymers contain occasional vinyl branches along the chain. How do you think these branches mightarise?
Tires whose sidewalls arc made of natural rubber tend to crack and weather rapidly in areas around cities where high levels of ozone and other industrial pollutants are found. Explain.
Would you expect allene, H2C = C = CH2, to show a UV absorption in the 200 to 400 urn range? Explain.
Which of the following compounds would you expect to have a ? ? ?* UV absorption in the 200 to 400 nm range?
Predict the products of the following Diels?Alder reactions;
Show the structure, including stereochemistry, of the product from the following Diels?Alder reaction:
How can you account for the fact that cis-1, 3-pentadicne is much less reactive than trans-1, 3-pentadiene in the Diels—Alder reaction?
Would you expect a conjugated diyne such as 1, 3-butadlyne to undergo Diels—Alder reaction with a dienophile explain.
Reaction of isoprene (2-methyl-1, 3-hutadiene) with ethyl propenoate gives a mixture of two Diels?Alder adducts. Show the structure of each, and explain why a mixture is formed.
Rank the following dienophiles in order of their expected reactivity in the Diels?Alder reaction.
1, 3-Cyclopentadiene is very reactive in Diels—Alder cyclo addition reactions, but 1, 3-cyclohexadiene is less reactive and 1, 3-cycloheptadiene is nearly inert. Explain. (Molecular models are
1, 3-Pentadiene is much more reactive in Diels?Alder reactions than 2, 4-pentadienal. Why might this be?
How could you use Diels?Alder reactions to prepare the following products? Show the starting diene and dienophile in each case.
Aldrin, a chlorinated insecticide now banned for use in the United States, can be made by Diels?Alder reaction of hexachloro-1, 3-cyclopentadiene with norbornadiene. What is the structure of aldrin?
Norbornadiene (Problem 14.41) can be prepared by reaction of chloroethylene with 1, 3-cyclopentadiene, followed by treatment of the product with sodium ethoxide. Write the overall scheme, and
We?ve seen that the Diels?Alder cyclo addition reaction is a one-step, pericyclic process that occurs through a cyclic transition state. Propose a mechanism for the following reaction:
In light of your answer to Problem 14.43, propose a mechanism for the followingreaction:
The triene shown here reacts with 2 equivalents of maleic an hydride to yield a product with the formula C17H16O6. Predict a structure for theproduct.
The following ultraviolet absorption maxima have been measured:1, 3-Butadiene 217 nm2-Mcthyl-1, 3-butadicne 220 nm1, 3-Pentadiene 223 nm2, 3-Dimethyl- 1, 3-hutadiene 226 nm2, 4-Hexadiene 227 nm2,
1, 3, 5-Hexatriene has λ max = 258 nm. In light of your answer to Problem 14.46, approximately where would you expect 2, 3-dimethyl-1, 3, 5-hexatriene to absorb?
?-Ocimene is a pleasant-smelling hydrocarbon found in the leaves of certain herbs. It has the molecular formula C10H16 and a UV absorption maximum at 232 nm. On hydrogenation with a palladium
Myrcene, C10H16, is found in oil of bay leaves and is isomeric with ?-Ocimene (Problem 14.48). It has an ultraviolet absorption at 226 nm and can be catalytically hydrogenated to yield 2,
Addition of HC1 to 1-methoxycyclohexene yields 1-chloro-1-methoxycyclo- hexane as the sole product. Use resonance structures to explain why none of the other regioisomer isformed.
Hydrocarbon A, C10H14, has a UV absorption at ? max = 236 nm and gives hydrocarbon B, C10H18, on catalytic hydrogenation. Ozonolysis of A followed by zinc/acetic acid treatment yields the following
Adiponitrile, a starting material used in the manufacture of nylon, can be prepared in three steps from 1, 3-butadiene. How would you carry out thissynthesis?
Ergo sterol a precursor of vitamin D, has ? max = 282 nm and molar absorptivity ? = 11,900. What is the concentration of ergo sterol in a solution whose absorbance A = 0.065 with a sample path length
A 1, 3-Cyclopentadiene polymerizes slowly at room temperature to yield a polymer that has no double bonds except on the ends. On heating, the polymer breaks down to regenerate 1, 3-cyclopentadiene.
A Dimethyl butynedioate undergoes a Diels?Alder reaction with (ZE, 4E)-hexadiene. Show the structure and stereochemistry of the product.
Dimethyl butynedioate also undergoes a Diels—Alder reaction with (2E, 4Z)-hexadiene, but the stereochemistry of the product is different from that of the (2E, 4E) isomer (Problem 14.55). Explain.
How would you carry out the following synthesis (more than one step is required)? What stereo chemical relationship between the ?CO2CH3 group attached to the cyclohexane ring and the ?CHO groups
The double bond of an enamine (alkene amine) is much more nucleophilic than a typical alkene double bond. Assuming that the nitrogen atom in an enamine is sp2-hybridized, draw an orbital picture of
Benzene has an ultraviolet absorption at ? max = 204mm, and para-toluidine has ? max = 235nm. How do you account for this difference?
What product would you expect to obtain from a nucleophilic substitution reaction of (S)-2-bromohexane with acetate ion, CH3CO2 –? Assume that inversion of configuration occurs, and show the stereo
What product would you expect to obtain from SN2 reaction of OH – with (R)-2-bromo-butane? Show the stereo chemistry of both reactant and product.
Assign configuration to the following substance, and draw the structure of the product that would result on nucleophilic substitution reaction with HS ? (reddish brown = Br):
What product would you expect from SN2 reaction of 1-bromobutane with each of the following?(a) NaI(b) KOH(c) H – C ≡ C – Li(d) NH3
Which substance in each of the following pairs is more reactive as a nucleophile? Explain.(a) (CH3)2N – or (CH3)2NH(b) (CH3)3B or (CH3)3N(c) H2O or H2S
Rank the following compounds in order of their expected reactivity toward SN2 reaction:CH3Br, CH3OTos, (CH3)3CCl, (CH3)2CHCl
Organic solvents such as benzene, ether, and chloroform are neither protic nor strongly polar. What effect would you expect these solvents to have on the reactivity of a nucleophile in SN2 reactions?
What product(s) would you expect from reaction of (S)-3-chloro-3-methyloctane with acetic acid? Show the stereo chemistry of both reactant and product.
Among the numerous examples of SN1 reactions that occur with incomplete racemization is one reported by Winstein in 1952? The optically pure tosylate of 2, 2-dimethy-1-phenyl-1-propanol ([?] D = ?
Assign configuration to the following substrate, and show the stereo chemistry and identity of the product you would obtain by SN1 reaction with water (reddish brown =Br):
Rank the following substances in order of their expected SN1 reactivity:
3-Bromo-1-butene and 1-bromo-2-butene undergo SN1 reaction at nearly the same rate even though one is a secondary halide and the other is primary. Explain
Predict whether each of the following substitution reactions is likely to be SN1 orSN2.
Review the mechanism of geraniol biosynthesis shown in Figure and then propose a mechanism for the biosynthesis of limonene from linalyldiphosphate.
Ignoring double-bond stereo chemistry, what products would you expect from elimination reactions of the following alkyl halides? Which will be the major product in eachcase?
What alkyl halides might the following alkenes have been madefrom?
What stereo chemistry do you expect for the alkene obtained by E2 elimination of (1R, 2R)-1, 2-dibromo-1, 2-diphenylethane? Draw a Newman projection of the reacting conformation?
What stereo chemistry do you expect for the tri-substituted alkene obtained by E2 elimination of the following alkyl halide on treatment with KOH? (Reddish brown =Br.)
Which isomer would you expect to undergo E2 elimination faster, trans1-bromo-4-tert-butylcyclohexane or cis-1-bromo-4-tert-butylcyclohexane? Draw each molecule in its more stable chair conformation,
Tell whether each of the following reactions is likely to be SN1, SN2, E1, E1cB, orE2:
Write the product you would expect from reaction of each of the following alkyl halides with (i) Na+?SCH3 and (ii) Na+??OH (yellow-green = Cl):
From what alkyl bromide was the following alkyl acetate made by SN2 reaction? Write the reaction, showing allstereochemistry.
Assign R or S configuration to the following molecule, write the product you would expect from SN2 reaction with NaCN, and assign R or S configuration to the product (yellow-green =Cl):
Draw the structure and assign Z or F stereochemistry to the product you expect from E2 reaction of the following molecule with NaOH (yellow-green =Cl):
Which compound in each of the following pairs will react faster in an SN2 reaction with OH–?(a) CH3Br or CH3I(b) CH3CH2I in ethanol or in dimethyl sulfoxide(c) (CH3) 3CC1 or CH3C1(d) H2C = CHBr or
What effect would you expect the following changes to have on the rate of the SN2 reaction of 1-iodo-2-methylbutane with cyanide ion?(a) The CN– concentration is halved, and the
What effect would you expect the following changes to have on the rate of the reaction of ethanol with 2-iodo-2-methylbutane?(a) The concentration of the halide is tripled.(b) The concentration of
How might you prepare each of the following molecules using a nucleophilic substitution reaction at somestep?
A Which reaction in each of the following pairs would you expect to be faster?(a) The SN2 displacement by I – on CH3CI or on CH3OTos(b) The SN2 displacement by CH3CO2 on bromomethane or on bromo
What products would you expect from the reaction of 1-bromopropane with each of the following?(a) NaNH2(b) KOC (CH3)3(c) NaI(d) NaCN(e) NaC ≡ CH(f) Mg, then H2O
Which reactant in each of the following pairs is more nucleophilic? Explain.(a) –NH2 or NH3(b) H2O or CH3CO2–(c) BF3 or F–(d) (CH3)3P or (CH3)3N(e) I– or Cl–(f) –C ≡ N or –OCH3
Propose structures for compounds that fit the following descriptions:(a) An alkyl halide that gives a mixture of three alkenes on E2 reaction(b) An organo halide that will not undergo nucleophilic
Draw all isomers of C4H9Br, name them, and arrange them in order of decreasing reactivity in the SN2 reaction.
The following Walden cycle has been carried out. Explain the results, and indicate where Walden inversion isoccurring.
The reactions shown below are unlikely to occur as written. Tell what is wrong with each, and predict the actualproduct.
Order each of the following sets of compounds with respect to SN1reactivity:
Order each of the following sets of compounds with respect to SN2reactivity:
Predict the product and give the stereochemistry resulting from reaction of each of the following nucleophiles with (R)-2-bromooctane:(a) –CN(b) CH3CO2–(c) CH3S–
(R)-2-Bromooctanc undergoes racemization to give (±) -2-bromooctane when treated with NaBr in dimethyl sulfoxide. Explain.
Reaction of the following S tosylate with cyanide ion yields a nitrile product that also has S stereochemistry.Explain.
Ethers can often be prepared by SN2 reaction of alkoxide ions, RO?, with alkyl halides. Suppose you wanted to prepare cyclohexyl methyl ether. Which of the two possible routes shown below would you
We saw in Section 7.8 that bromohydrin are converted into epoxides when treated with base. Propose a mechanism, using curved arrows to show the electronflow.
Show the stereochemistry of the epoxide you would obtain by formation of a bromohydrin from trans-2-butene, followed by treatment with base.
In light of your answer to problem 11.42, what product might you expect from treatment of 4-hrorno-l-butanol withbase?
The following tertiary alkyl bromide does not undergo a nucleophilic substitution reaction by either SN1 or SN2 mechanisms.Explain.

Showing 2900 - 3000 of 15575

First
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
Last

Services

Sitemap
Fun
Definitions
Become Tutor
Study Help Categories
Recent Questions
Expert Questions

Company Info

Security
Copyrights
Privacy Policy
Terms & Conditions
SolutionInn Fee
Scholarship

Get In Touch

About Us
Contact Us
Career
Jobs
FAQ
Campus Ambassador

Secure Payment

Download Our App

© 2024 SolutionInn. All Rights Reserved