Interpretation: The product formed by
Concept introduction: In the sigmatropic rearrangement, the rearrangement of pi bond and the breaking of sigma bond take place. This results in the generation of new sigma bond in the product. In this type of rearrangement, the number of pi bonds remains constant in the reactant as well as in the product.
Curved arrows aid in determining the movement and flow of electrons in the reaction. The electrons that take part in the
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Chapter 27 Solutions
Package: Loose Leaf for Organic Chemistry with Biological Topics with Connect Access Card
- (a) Which diastereomer of oct-4-ene yields a mixture of two enantiomers, (4R,5R)- and (4S, 5S)-4,5-dibromooctane on reaction with Br2? (b) Which diastereomer of oct-4-ene yields a single meso compound, (4R, 5S)-4,5-dibromooctane?arrow_forwardWhat product is formed by the [3,3] sigmatropic rearrangement of each compound?arrow_forwardAlthough there are nine stereoisomers of 1,2,3,4,5,6hexachlorocyclohexane, one stereoisomer reacts 7000 times more slowly than any of the others in an E2 elimination. Draw the structure of this isomer and explain why this is so.arrow_forward
- Predict the structure (stereochemistry) of the dibromide products of a synaddition of bromine to trans-cinnamic acid. Predict the structure (stereochemistry) of the dibromide products of an antiaddition of bromine to trans-cinnamic acid.Label each product as threo or erytho.It may be helpful to construct molecular models of threo-and erytho-2,3-dibromo-3-phenylpropanioc acid.arrow_forwardDehydrohalogenation of 1-chloro-1-methylcyclopropane affords two alkenes (A and B) as products. Explain why A is the major product despite the fact that it contains the less substituted double bond.arrow_forwardWhen buta-1,3-diene (CH2 = CH – CH = CH2) is treated with HBr, two constitutional isomers are formed, CH3CHBrCH = CH2 and BrCH2CH = CHCH3. Draw a stepwise mechanism that accounts for the formation of both products.arrow_forward
- Friedel–Crafts alkylation of benzene with (R)-2-chlorobutane and AlCl3 affords sec-butylbenzene. How many stereogenic centers are present in the product?arrow_forwardGive the structure of the major diastereoisomer formed in the two reactions below. Explain the stereochemical outcome with the aid of Newman projections/transition state diagrams.arrow_forwardElimination occurs when (Z)-3-bromohex-3-ene is treated with NaNH2. Under the same conditions, 1-bromocyclohexeneundergoes elimination much more sluggishly. Explain whyarrow_forward