Interpretation:
Given that the treatment of α-bromoacetophenone, obtained from acetophenone by bromination, with NaBH4 yields an
Concept introduction:
The nucleophilic attack attack of the hydride ion on the carbonyl carbon of the bromoketone and the following internal nucleophilic attack by the negatively charged oxide ion and to eliminate a bromide ion will lead to the formation of the epoxide.
To give:
Given that the treatment of α-bromoacetophenone, prepared from acetophenone, with NaBH4 yields an epoxide. The structure of the epoxide is to be shown and its formation is to be explained.
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Chapter 18 Solutions
ORGANIC CHEM.(LL)-W/OWL V2 >CUSTOM<
- Show the products you would obtain by acid-catalyzed reaction of cyclohexanone with ethylamine, CH3CH2NH2, and with diethylamine, (CH3CH2) 2NH.arrow_forwardA step in a synthesis of PGE1 (prostaglandin E1, alprostadil) is the reaction of a trisubstituted cyclohexene with bromine to form a bromolactone. Propose a mechanism for formation of this bromolactone and account for the observed stereochemistry of each substituent on the cyclohexane ring. Alprostadil is used as a temporary therapy for infants born with congenital heart defects that restrict pulmonary blood flow. It brings about dilation of the ductus arteriosus, which in turn increases blood flow in the lungs and blood oxygenation.arrow_forwardTreatment of 1-aminoadamantane, C10H17N, with methyl 2,4-dibromobutanoate in the presence of a nonnucleophilic base, R3N, involves two successive SN2 reactions and gives compound A. Propose a structural formula for compound A.arrow_forward
- Propose a mechanism for the acid-catalyzed hydration of methylidenecyclohexane to give 1-methylcyclohexanol. Which step in your mechanism is rate-determining?arrow_forwardPropose a mechanism for the reaction of 1-methylcyclohexanol with HBr to form 1-bromo-1-methylcyclohexanearrow_forwardWhat is the best set of reagents to achieve deoxygenation of 2-pentanone to pentane? A. NaClO2/NaH2PO4 B. LiAlH4, Et2O C. DIBAL-H, THF D. NH2NH2/t-BuOK, DMSOarrow_forward
- The base-promoted rearrangement of an a-haloketone to a carboxylic acid, known as the Favorskii rearrangement, is illustrated by the conversion of 2-chlorocyclohexanone to cyclopentanecarboxylic acid. Jo Han Sow La NaOH, THF O Nat H3O+ OH NaOH, THF The mechanism involves the following 5 steps: -ō cyclopropanone intermediate 1. Abstraction of a proton to form enolate anion 1; 2. Formation of a cyclopropanone intermediate 2 with expulsion of chloride ion; 3. Addition of hydroxide ion to form tetrahedral intermediate 3; 4. Collapse of the tetrahedral intermediate and breakage of the three-membered ring to form carbanion intermediate 4; 5. Proton transfer to form the rearranged carboxylic acid. For the following reaction, draw the reaction out on paper, and then draw the structure of cyclopropanone intermediate 2 in the window. 1. NaOH, THF 2. H3O* OHarrow_forwardThe Favorskii reaction involves treatment of an -bromo ketone with base to yield a ring-contracted product. For example, reaction of 2-bromocyclohexanone with aqueous NaOH yields cyclopentanecarboxylic acid. Propose a mechanism.arrow_forwardPropose a mechanism to account for the formation of 3, 5-dimethyl- pyrazole from hydrazine and 2, 4-pentanedione. Look carefully to see what has happened to each carbonyl carbon in going from starting material to product.arrow_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning