Concept explainers
(a)
Interpretation: The structure of major organic product that would result from reaction of
Concept introduction: Carbocation formation is relatively slower than acid-base reactions. Carbocations generated from
Analogous to the case that strong nucleophiles are more favored to react via
(b)
Interpretation: The structure of major organic product that would result from reaction of
Concept introduction: Carbocation formation is relatively slower than acid-base reactions. Carbocations generated from alkyl halides have two fates; they can be either trapped by nucleophiles to give substitution product or may deprotonated to yield small amount of alkene. Stronger the base more is the probability of elimination over substitution over elimination. Further, if still higher concentration is employed reaction proceeds via bimolecular elimination. On the other hand, weak base waits until the carbocation is formed and the type of elimination with relatively weak base is two-step elimination or
Analogous to the case that strong nucleophiles are more favored to react via
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Organic Chemistry: Structure and Function
- Please give the main substitution product for each of the following reactions, and indicate the dominant mechanism: (a) 1-bromopropane + NaOCH3 → (b) 3-bromo-3-methylpentane + NaOC2H5 →arrow_forwardAcid-catalyzed dehydration of neopentyl alcohol, (CH3)3CCH2OH, yields 2-methyl-2- butene as the major product. Outline a mechanism showing all steps in its formation.arrow_forwardThe reaction below is the addition of HCl to 3-methylenecyclohex-1-ene. CH2 + HCI (i) Draw and name the kinetic and thermodynamic products structures of this reaction. (ii) Show the mechanism of reaction, while explaining the kinetic and thermodynamic preference of the reaction.arrow_forward
- Neopentyl alcohol, (CH3)3CCH2OH, reacts with concentrated HBr to give 2-bromo2-methylbutane, a rearranged product. Propose a mechanism for the formation of thisproduct.arrow_forward(a) In an acid-catalyzed hydration, one of the following 10 carbon alkynes is expected to produce a single hydration product? Select the correct alkyne and draw the structure of the hydration product that is formed from this alkyne. (I) 2-decyne; (II) 3-decyne; (III) 4-decyne; (IV) 5-decyne; (V) none of these will give a single hydration product. (b) The reaction shown below gives Compound X as the major product. The mass spectrum of X is shown. Br2, H20 Compound X 100 - MS-IW-5644 80 60 40 - 20 - 20 40 60 80 100 120 140 160 180 200 220 m/z Considering the reactions of alkynes and the MS data, de duce which of following structures corresponds to X: Br Br HO, IV V I II II Support your answer with a reaction mechanism for fomation of X and identification of relevant peaks in the mass spectrum. 12 Relative Intensityarrow_forwardDescribe the reaction mechanism for the hydrolysis of 2-bromo-2-methylpropane [CH3C(CH3)2Br] with aqueous hydroxide ions (OH-).The description should be detailed and must include the type of bond fission that takes place. You may sketch and insert suitable diagrams to aid your description if you wisharrow_forward
- (b) Predict the suitable solvent (H2O or CH3COCH:) to increase the reaction of bromopropane (CH3CH2CH2B1) with sodium hydroxide (NaOH). Two reactions are shown below: NaOH, 55 °C CH;CH,CH,Br CH;CH,CH,OH + + NaBr H,O (i) NaOH, 55 °C CH;CH,CH,Br CH;CH,CH,OH + NaBr (ii) H,C- CH3arrow_forwardThe reaction of 2,2-dimethyl-1-propanol [(CH3)3CCH2OH], also known by the common name neopentyl alcohol, with HBr is very slow and gives 2-bromo-2-methylbutane as the major product.Give a mechanistic explanation for these observations.arrow_forwardTreatment of 2-bromo-2-methylbutane with KOH in ethanol yields a mixture of two Alkenes products. What are their likely structures? Show its mechanism.arrow_forward
- 4. Protonation of alcohol A and subsequent loss of water, produces the intermediate B. CH3 CH; CH, CH, — с — сH, CH, CH;CH, - C- CH, CH; | OH A B (a) (i) Name alcohol A. (11) What type of species is intermediate B? (iii) Draw the structures of the two alkenes which can be formed from species B by removal of a proton. Label as C the alkene which shows geometrical isomerism. (b) The intermediate B is readily attacked by nucleophiles such as water. What is the essential feature of a nucleophile? (c) State what final colour you would see if alcohol A were warmed with acidified potassium dichromate(VI). Explain your answer. Colour Explanation . (ii) Draw two structural isomers of alcohol A which form branched chain ketones when heated with acidified potassium dichromate(VI), but which could not form alkene C on dehydration.arrow_forwardb) Refer to the following equation to answer Q3b (i), (ii) and (iii). CH3 H,SO, Н—с—он C-CH3 ? + H2O Но- ČH3 (i) Determine the product of the above reaction. (ii) Name the above reaction. (iii) Propose the mechanism for the above reaction.arrow_forwardThe following sequence of steps converts (R)-2-octanol to (S)-2-octanol. Propose structural formulas for intermediates A and B, specify the configuration of each, and account for the inversion of configuration in this sequence.arrow_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning