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
Package: Loose Leaf for Organic Chemistry with Biological Topics with Connect Access Card
- For alkenes A, B, C, and D: (a) Rank A—D in order of increasing heat of hydrogenation; (b) rank A—D in order of increasing rate of reaction with H2, Pd-C; (c) draw the products formed when each alkene is treated with ozone, followed by Zn, H2O.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_forward(a) Draw all products formed by treatment of each dibromide (A and B) with one equivalent of NaNH2. (b) Label pairs of diastereomers and constitutional isomers. H Br H Br CH3 CH3 Br H H Br Aarrow_forward
- What 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(a) What alkene yields A and B when it is treated with Br2 in CCl4? (b) What alkene yields C and D under the same conditions?arrow_forwardDraw the organic products formed when cyclopentene is treated withfollowing reagent. [1] CH3CO3H; [2] H2O, HO−arrow_forward
- Consider the tetracyclic compound with rings labeled A–D. (a) Which ring is the most reactive in electrophilic aromatic substitution? (b) Which ring is the least reactive in electrophilic aromatic substitution?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_forwardWhen 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_forward
- Draw 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_forwardEthylene oxide reacts readily with HO- because of the strain in the three-membered ring. Explain why cyclopropane, a compound with approximately the same amount of strain, does not react with HO-.arrow_forwardDraw all of the substitution and elimination products formed from the given alkyl halide with each reagent: (a) CH3OH; (b) KOH. Indicate the stereochemistry around the stereogenic centers present in the products, as well as the mechanism by which each product is formed.arrow_forward