Concept explainers
(a)
Interpretation: The product formed on thermal electrocyclic ring opening of the given compounds 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 thermal conditions undergoes reaction in conrotatory fashion and polyene containing odd number of bonds undergo reaction in disrotatory fashion.
(b)
Interpretation: The product formed on photochemical electrocyclic ring opening of the given compounds.
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.
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Chapter 27 Solutions
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- Draw the product formed when each triene undergoes electrocyclic reaction under [1] thermal conditions; [2] photochemical conditions.arrow_forwardDraw all of the substitution and elimination products formed from thegiven alkyl halide with each reagent: (a) CH3OH; (b) KOH. Indicate thestereochemistry around the stereogenic centers present in the products,as well as the mechanism by which each product is formed.arrow_forwardWhat product is formed when each compound undergoes thermal electrocyclic ring opening or ring closure? Label each process as conrotatory or disrotatory and clearly indicate the stereochemistry around tetrahedral stereogenic centers and double bonds.arrow_forward
- Draw the organic products formed when cyclopentene is treated withfollowing reagent. [1] CH3CO3H; [2] H2O, HO−arrow_forward| Anthracene readily undergoes a Diels-Alder reaction with tetracyanoethene, even though anthracene is NC CN ? + aromatic. NC CN (a) Draw two possible products that can form from this reaction. (b) Explain why anthracene can readily undergo a Diels-Alder reaction, whereas benzene does not.arrow_forwardDraw the alkene that would react with the reagent given to account for the product formed. ? + H₂O H₂SO4 CH3 CH3 CHCCH3 OH CH3 • You do not have to consider stereochemistry. • You do not have to explicitly draw H atoms. • In cases where there is more than one answer, just draw one. Sn [F ChemDoodlearrow_forward
- When norbornene undergoes hydroboration-oxidation, a mixture of two stereoisomers is produced in a roughly 6:1 ratio. (a) Draw both of these isomeric products. (b) Which product is favored? Hint: You should build a model of norbornene and consider the transition state leading to each product. 1. BH3 THF ? 2. H2O2, NaOH, H,O Norbornenearrow_forwardFor alkenes A, B, and C: (a) Rank A, B, and C in order of increasing heat of hydrogenation; (b) rank A, B, and C in order of increasing rate of reaction with Hạ, Pd-C; (c) draw the products formed when each alkene is treated with ozone, followed by Zn, H,0. A. Barrow_forwardFor alkenes A, B, C, and D: (a) Rank A—D in order of increasing heat ofhydrogenation; (b) rank A—D in order of increasing rate of reaction withH2, Pd-C; (c) draw the products formed when each alkene is treated withozone, followed by Zn, H2O.arrow_forward
- The bicyclic heterocycles quinoline and indole undergo electrophilic aromatic substitution to give the products shown. (a) Explain why electrophilic substitution occurs on the ring without the N atom for quinoline, but occurs on the ring with the N atom in indole. (b) Explain why electrophilic substitution occurs more readily at C8 than C7 in quinoline. (c) Explain why electrophilic substitution occurs more readily at C3 rather than C2 of indole.arrow_forwardDraw the alkene that would react with the reagent given to account for the product formed. ? + H₂O H₂SO4 CH3 CH3CCH3 OH You do not have to consider stereochemistry. You do not have to explicitly draw H atoms. • In cases where there is more than one answer, just draw one. Sn [F ChemDoodleⓇarrow_forwardRank compound A, B, and C in the order of increasing stability.arrow_forward