(a)
Interpretation: The stereochemistry of given reaction is to be predicted.
Concept introduction: Cycloaddition reactions are pericyclic reactions that take place in two compounds containing pi bonds to form a cyclic compound. These reactions are concerted and stereospecific in nature. According to Woodward-Hoffmann rules, the polyene containing even number of bonds in thermal conditions undergoes reaction in antrafacial fashion and polyene containing odd number of bonds undergo reaction in suprafacial fashion. The total number of bonds present in the
(b)
Interpretation: The stereochemistry of given reaction is to be predicted.
Concept introduction: Electrocyclic reactions involve ring opening or ring closure in a conjugated polyene. According to Woodward-Hoffmann rules, the polyene containing even number of bonds in photochemical conditions undergoes reaction in disrotatory fashion and polyene containing odd number of bonds undergo reaction in conrotatory fashion.
(c)
Interpretation: The stereochemistry of given reaction is to be predicted.
Concept introduction: Cycloaddition reactions are pericyclic reactions that take place in two compounds containing pi bonds to form a cyclic compound. These reactions are concerted and stereospecific in nature. According to Woodward-Hoffmann rules, the polyene containing even number of bonds in photochemical conditions undergoes reaction in suprafacial fashion and polyene containing odd number of bonds undergo reaction in antrafacial fashion. The total number of bonds present in the alkenes is considered.
(d)
Interpretation: The stereochemistry of given reaction is to be predicted.
Concept introduction: Sigmatropic rearrangements are pericyclic reactions which takes place by concerted mechanism. In these rearrangements migration of sigma bond takes place. According to Woodward-Hoffmann rules, the total number of electron pairs in sigma bond that is broken and the pi bonds that rearrange. The polyene containing even number of electron pairs and bonds in thermal conditions undergoes reaction in antrafacial fashion and polyene containing odd number of electron pairs and bonds undergo reaction in suprafacial fashion.
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Chapter 25 Solutions
Connect Online Access 1-Semester for Organic Chemistry
- Q1: For each molecule, assign each stereocenter as R or S. Circle the meso compounds. Label each compound as chiral or achiral. OH HO CI Br H CI CI Br CI CI Xf x f g Br D OH Br Br H₂N R. IN Ill I -N S OMe D II H CO₂H 1/111 DuckDuckGarrow_forwardThese are synthesis questions. You need to show how the starting material can be converted into the product(s) shown. You may use any reactions we have learned. Show all the reagents you need. Show each molecule synthesized along the way and be sure to pay attention to the regiochemistry and stereochemistry preferences for each reaction. If a racemic molecule is made along the way, you need to draw both enantiomers and label the mixture as "racemic". All of the carbon atoms of the products must come from the starting material! ? H Harrow_forwardQ5: Draw every stereoisomer for 1-bromo-2-chloro-1,2-difluorocyclopentane. Clearly show stereochemistry by drawing the wedge-and-dashed bonds. Describe the relationship between each pair of the stereoisomers you have drawn.arrow_forward
- Classify each pair of molecules according to whether or not they can participate in hydrogen bonding with one another. Participate in hydrogen bonding CH3COCH3 and CH3COCH2CH3 H2O and (CH3CH2)2CO CH3COCH3 and CH₂ CHO Answer Bank Do not participate in hydrogen bonding CH3CH2OH and HCHO CH3COCH2CH3 and CH3OHarrow_forwardNonearrow_forwardQ4: Comparing (3S,4S)-3,4-dimethylhexane and (3R,4S)-3,4-dimethylhexane, which one is optically active? Briefly explain.arrow_forward
- Nonearrow_forwardNonearrow_forwardGiven the standard enthalpies of formation for the following substances, determine the reaction enthalpy for the following reaction. 4A (g) + 2B (g) → 2C (g) + 7D (g) AHrxn =?kJ Substance AH in kJ/mol A (g) - 20.42 B (g) + 32.18 C (g) - 72.51 D (g) - 17.87arrow_forward
- Determine ASran for Zn(s) + 2HCl(aq) = ZnCl2(aq) + H2(aq) given the following information: Standard Entropy Values of Various Substance Substance So (J/mol • K) 60.9 Zn(s) HCl(aq) 56.5 130.58 H2(g) Zn2+(aq) -106.5 55.10 CI (aq)arrow_forward3) Catalytic hydrogenation of the compound below produced the expected product. However, a byproduct with molecular formula C10H12O is also formed in small quantities. What is the by product?arrow_forwardWhat is the ΔHorxn of the reaction? NaOH(aq) + HCl(aq) → H2O(l) + NaCl(aq) ΔHorxn 1= ________ kJ/molarrow_forward
