The poison gelsemoxonine can be isolated from the leaves of a plant native to southeastern Asia (Gelsemium elegans). A key step in a synthesis of this natural product involves a thermally initiated (70°C) sigmatropic rearrangement of the compound shown below (R=protecting group) (J. Am. Chem. Soc. 2011, 133, 17634-17637). Me, Sio `N-OMe RO

The poison gelsemoxonine can be isolated from the leaves of a plant native to southeastern Asia (Gelsemium elegans). A key step in a synthesis of this natural product involves a thermally initiated (70°C) sigmatropic rearrangement of the compound shown below (R=protecting group) (J. Am. Chem. Soc. 2011, 133, 17634-17637). Me, Sio `N-OMe RO

Organic Chemistry

9th Edition

ISBN:9781305080485

Author:John E. McMurry

Publisher:John E. McMurry

Chapter14: Conjugated Compounds And Ultraviolet Spectroscopy

Section14.SE: Something Extra

Problem 50AP: -Ocimene is a pleasant-smelling hydrocarbon found in the leaves of certain herbs. It has the...

See similar textbooks

Similar questions

divls depends oin the moisture content of the reaction mixture. Propose a detailed mechanism for ench of the following steps to account for the observed The outeome of oxidation of alkenes with 1odine and silver acetate to afford stereochemistry of the product HO () 2, 2 RCO2Ag (i1) NaOH (aq) HO HO () 2, RCO2Ag, H20 (11) NaOH (aq) HO
(10pts) Compound A, C10H16, was found to be optically active. On catalytic reduction over a palladium catalyst, 2 equivalents of hydrogen were absorbed, yielding compound B, CioH2o. On ozonolysis of A, two fragments were obtained. One fragment was identified as acetic acid (CHCOOH). The other fragment, compound C, was an optically active carboxylic acid, C8H14O2. Write reactions, and draw the correct structures for A-C, explain your answer in detail.
(ii) Draw the product R, including a detailed reaction mechanism for the conjugate addition reaction between the 1,3-dicarbonyl P and the a,ß-unsaturated ketone Q. Eto P OEt + Q OEt Et3N R (iv) Explain why conjugate addition is favoured over direct addition to Q in this case.
Rank the compounds in each group in order of increasing reactivity in electrophilic aromatic substitution: (a) C6H6, C6H5Cl, C6H5CHO; (b) C6H5CH3, C6H5NH2, C6H5CH2NH2.
Q12. (1-bromoethyl)benzene 1 udergoes an elimination following an E1 mechanism. Fill in the following synthetic scheme by drawing the structure of intermediate 2 and product 3. The chemical formula of product 3 is provided as guidance. CH; RDS Br C3Hg E1 2 3
Compound 1 has been shown to be a useful precursor in the synthesis of natural products. (Org. Lett. 2004, 6, 4439-4442). In principle, four stereoisomers are possible when this compound is subjected to catalytic hydrogenation. Draw these stereoisomers and describe their relationships. HO O OH H₂ - ? Pt Modify the four structures below, as necessary, to draw the four stereoisomers that are possible from catalytic hydrogenation of compound 1. Use the single bond tool to interconvert between double and single bonds.
Dichloromethane (CH,Cl,) can be treated with butyllithium, CH3CH,CH,CH,-Li (Bu-Li), to make a carbene in situ, analogous to the way a carbene is generated from trichloromethane (CHCI3) using HO¯. (a) Show the mechanism for the generation of a carbene from CH2CI2. (b) Why is butyllithium used instead of HO-? (c) The reaction shown here leads to a mixture of four products. Draw all four products. CH,Cl, ? Bu-Li Draw the mechanism for this reaction
7B. (2 reactions (should clearly indicate the stereochemistry). Draw the structure of the product, substrate or condition in the following (a) ОН (b) Ме 1) OsO4 2) NaHSO3 (c) 1) (sia)2BH 2) NaOH/H2O2 H20
Provide the products for the reactions shown below. Suggest a reasonable mechanism (show electron flow or provide a brief explanation) to account for each step, paying attention to stereochemical details. (a) OBn 1. EtO)2CO, NaOEt 2. H* 3. H₂O*, heat 1. NaH, THF 2. Br, THF
Q12. (1bremeetblbenzene 1 ydergOesan elimination following an E1 mechanism. Fill in the following synthetic scheme by drawing the structure of intermediate 2 and product 3. The chemical formula of product 3 is provided as guidance.
The dragmacidin class of natural products has been isolated from various marine sponges. They have been shown to have many interesting biological properties, including anti-viral, anti-fungal, and anti-bacterial activity. (+)- Dragmacidin D, shown below, was also made in the laboratory, which allowed the structure to be confirmed (Org. Lett. 2015, 17, 1529-1532). Part 1 ΗΘΗ H-N N-H * (-6) R (+)-Dragmacidin D R = "N-H The positive charge in dragmacidin D is delocalized. Draw all resonance structures that show delocalization of this charge, by modifying the given structures as needed. Include the original structure as one of the possible resonance forms, and include relevant formal charges in your structures. Do not add any resonance arrows or curved arrows. Use the + and - tools to add/remove charges to an atom, and use the single bond tool to add/remove double bonds. Br -H
Possible alternative brominations include: Veratrole (1,2-dimethoxybenzene) to 1,2-dibromo-4,5-dimethoxybenzene; 4-Methylacetanilide to 2-bromo-4-methylacetanilide; 2-Methylacetanilide (made in experiment S.1) to 4-bromo-2-methylacetanilide; Vanillin to 5-bromovanillin; Acetanilide to 4-bromoacetanilide; a. b. C. d. e. EXPERIMENT S4: BROMINATION OF AROMATIC COMPOUNDS Certain other acetanilides made in experiment S.1 may also be used as precursors in this experiment. Estimated time: 1 afternoon Associated learning goals: Section 6, LG 6.6; Section 7, LG 7.2 and 7.4 Pre-lab report: complete the standard report form, and answer the following questions. In this experiment, molecular bromine (Br2) is generated from the redox reaction of potassium bromate with hydrobromic acid. Write a balanced equation for this process. Briefly outline the mechanism by which Br2 brominates your aromatic compound. Why do the bromine atoms end up at the positions indicated rather than anywhere else in the…