23.9 Intramolecular Claisen Condensations: The Dieckmann Cyclization Intramolecular Claisen condensation Best with 1,6- diesters (product: 5-membered B-ketoester) and 1,7-diesters (product: 6- membered ß- ketoester) OEt OEt Diethyl heptanedioate (a 1,7-diester) 2007 Thomson Higher Education 1. Na OEt, ethanol 2. H3O+ OEt + EtOH Ethyl 2-oxocyclohexanecarboxylate 24

23.9 Intramolecular Claisen Condensations: The Dieckmann Cyclization Intramolecular Claisen condensation Best with 1,6- diesters (product: 5-membered B-ketoester) and 1,7-diesters (product: 6- membered ß- ketoester) OEt OEt Diethyl heptanedioate (a 1,7-diester) 2007 Thomson Higher Education 1. Na OEt, ethanol 2. H3O+ OEt + EtOH Ethyl 2-oxocyclohexanecarboxylate 24

Organic Chemistry

9th Edition

ISBN:9781305080485

Author:John E. McMurry

Publisher:John E. McMurry

Chapter27: Biomolecules: Lipids

Section27.SE: Something Extra

Problem 47AP: Cembrene, C20H32, is a diterpenoid hydrocarbon isolated from pine resin. Cembrene has a UV...

See similar textbooks

Similar questions

Tranexamic acid, a drug useful against blood clotting, is prepared commercially from p-methylbenzonitrile. Formulate the steps likely to be used in the synthesis. (Donâ€™t worry about cis-trans isomers; heating to 300 C interconverts the isomers.)
A 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.
Treatment of p-bromotoluene with NaOH at 300Â°C yields a mixture of two products, but treatment of m-bromotoluene with NaOH yields a mixture of three products. Explain.
Cembrene, C20H32, is a diterpenoid hydrocarbon isolated from pine resin. Cembrene has a UV absorption at 245 nm, but dihydrocembrene (C20H34), the product of hydrogenation with 1 equivalent of H2, has no UV absorption. On exhaustive hydrogenation, 4 equivalents of H2 react, and octahydrocembrene, C20H40, is produced. On ozonolysis of cembrene, followed by treatment of the ozonide with zinc, four carbonylcontaining products are obtained: Propose a structure for cembrene that is consistent with its formation from geranylgeranyl diphosphate.
Propose a structure for the product with formula C9H17N that results when 2-(2-cyanoethyl)cyclohexanone is reduced catalytically.
3. Provide a mechanism for the following transformation: N-C OH H3C H3C SOCI₂ CH 3 2 eq. pyridine CN H3C + SO2 + 2 4. Provide a mechanism for the following transformation: H es-CEN DMF 80-CEN A
10. Propose the mechanism for the following transformation: omy-of ww
The following reactions have been used to synthesize dieldrin and aldrin (named for Diels and Alder), two pesticides having a similar story to DDT (Section 7.4). Identify the lettered compounds in this reaction scheme. C CI + x MCPBA (1 equiv) A dieldrin aldrin
What is the best description of the product distribution from the reaction shown (- OTF=triflate, trifluoromethanesulfonate) Na OH,coo CH, COOHH,0 C D. DA mixture of compounds B and D OA mixture of compounds A and C OA mixture of compounds A and B OA mixture of compounds A and D
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* OH
What is an appropriate systematic name for the following? OH CI (1S,2R)-2-hydroxycyclopentanecarbonyl chloride O (15,2 R)-2-hydroxypentanoyl chloride (1R,2S)-2-(chlorocarbonyl)cyclopentanol O (15,5R)-5-hydroxycyclopentanecarbonyl chloride
Give the major product(s) for each step of the following sequence of reactions: a) HO HNO3/H2SO4 Sn/HCI OH A B C (p-isomer only) b) OH CH3CI 1. NH, A Na2Cr207, H* В C AIC13 2. CНзBr Heat