Villanova CHM 2212 - Multistep synthesis problems

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Chemistry 2212 Organic Chemistry II Spring 2003Practice for the Final Examination: Multistep synthesis problems. 1. The below transformation is needed as part of the total synthesis of Vitamin D3. Indicate how the transformation could be carried out in the laboratory. Use whatever additional reagents are necessary.OHOHHH2. (a) Write the structures for all of the intermediates in the reaction sequence below: BrMgoetherAOBPBr3CDNaCNH2SO4, H2OheatE1. LiAlH42. H+, H2OFHCl, ZnCl2GAlCl3H + I2(b) Two possible products were obtained from the final reaction of problem two, but only one was isolated. The carbon and proton NMR spectra of the product are shown below. Give the structure of the isolated product.2.1 – multiplet, 2H2.9 – triplet, 4H7.1 – doublet, 2H7.2 – triplet, 2H3. Write out all steps, including the structures of all intermediates and the reagents needed to carry out the reactions, for the following multistep synthesis:CH2BrCHBr COOH4. Write out all steps, including the structures of all intermediates and the reagents needed to carry out the reactions, for the following multistep synthesis:R CH3OR CH3O5. Provide the structures for A–E. For compound E, a 1H NMR spectrum, 13C NMR spectrum, and IR spectrum are provided below. Explain how this data is consistent with your answer for the structure of E. CH3BrMgetherA(1) CO2(2) H+, H2OBPCl3CC+AlCl3DD(1) A(2) H+, H2OE13C NMR signals: 31.66, 72.41, 124.41, 126.56, 128.13, 149.18 ppm1H NMR:1.55 ppm – 6H2.05 ppm – 1H7.25 ppm – 2H7.36 ppm – 1H7.44 ppm – 2H6. Propose a method to synthesize 1-bromo-3-methylbutane from 2-butenal. There must be two or fewer carbon atoms for any reagents that you use in your synthesis.OH CH3CH3BrCH37. Propose a method to synthesize 1-sec-butyl-propenyl-benzene from 1-phenyl-propan-1-one. CH2CH3OCHCH3CH3HCH2CH38. Propose a method to synthesize (3-nitro-phenyl)-methanol from benzaldehyde.


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Villanova CHM 2212 - Multistep synthesis problems

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