Interpretation:
A mechanism for the thermal rearrangement of vinyl substituted cyclopropanes in to cyclopentenes identifying the pericyclic process involved is to be proposed.
Concept introduction:
Sigmatropic rearrangements involve the migration of a σ bond present at the end or in the middle of the system across the π electron system from one position to another. They are represented by [m,n] where m and n represents the number of atoms between the bond being broken and the bond being formed in two directions.
If even number of electron pair is involved then thermal reaction occur through antarafacial pathway and photochemical reactions occur through suprafacial pathway.
If odd number of electron pair is involved then thermal reaction occur through suprafacial pathway and photochemical reactions occur through antarafacial pathway.
To propose:
A mechanism for the thermal rearrangement of vinyl substituted cyclopropanes in to cyclopentenes identifying the pericyclic process involved.
Want to see the full answer?
Check out a sample textbook solutionChapter 30 Solutions
Organic Chemistry
- Aldehydes and ketones react with thiols to yield thioacetals just as they react with alcohols to yield acetals. Predict the product of the following reaction, and propose a mechanism:arrow_forwardIdentify two alkenes that react with HBr to form 1-bromo-1-methylcyclohexane without undergoing a carbocation rearrangement.arrow_forwardDescribe a sequence of reactions by which cis-2-pentene could be prepared from acetylene.arrow_forward
- On treatment with HBr, 3-Methyl-1-pentene undergoes addition and rearrangement to yield 3-Bromo-3-methylpentenearrow_forwardAcid-catalyzed dehydration of 3-methyl-2-butanol gives three alkenes: 2-methyl-2- butene, 3-methyl-1-butene, and 2-methyl-1-butene. Propose a mechanism to account for the formation of each productarrow_forwardA compound with formula C7H12O is treated with sodium borohydride in methanol to yield 2,2-dimethylcylopentanol. Write a reaction scheme showing the structures of the reactant, the reagents, and the product. Will the product be optically active? Explain.arrow_forward
- Treating cyclohexene with HBr in the presence of acetic acid gives bromocyclohexane (85%) and cyclohexyl acetate (15%). Br OCCH CH,COH + HBr Bromocyclohexane Cyclohexyl acetate (15%) Cyclohexene (85%) Propose a mechanism for the formation of the latter product.arrow_forwardTreatment of a hydrocarbon A (molecular formula C9H18) with Br2 in the presence of light forms alkyl halides B and C, both having molecular formula C9H17Br. Reaction of either B or C with KOC(CH3)3 forms compound D (C9H16) as the major product. Ozonolysis of D forms cyclohexanone and acetone. Identify the structures of A–D.arrow_forwardIdentify the following pericyclic reaction; explain the course, product distribution and stereochemistry of the reaction. Where the first product is produced 70% and the second product is produced 30%.arrow_forward
- α-Terpinene, C10H16, is a pleasant-smelling hydrocarbon that has been isolated from oil of marjoram. On hydrogenation over a palladium catalyst, α-terpinene reacts with 2 molar equivalents of H2 to yield a hydrocarbon, C10H20. On ozonolysis, followed by reduction with zinc and acetic acid, α-terpinene yields two products, glyoxal and 6-methyl-2,5- heptanedione. (a) How many degrees of unsaturation does a-terpinene have? (b) How many double bonds and how many rings does it have? (c) Propose a structure for a-terpinene.arrow_forwardThe bicyclic alkene P can be prepared by thermal electrocyclic ring closure from cyclodecadiene Q or by photochemical electrocyclic ring closure from cyclodecadiene R. Draw the structures of Q and R, and indicate the stereochemistry of the process by which each reaction occurs.arrow_forwardWhen 2-iodo-1,4-dimethylcyclohexane is heated in acetic acid, CH3COOH, a mixture of substitution and elimination products is obtained. Provide structures for all possible products, writing [not drawing] the name of the mechanism by which each one is formed.arrow_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning