Sp08_215_FE_key - Sp08_215_FE_key I(36 points Complete the...

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Sp08_215_FE_key A. ( JOC , 2007 , 72 , 9298) O O O HCl (aq) heat I. (36 points ) H OCH 2 CH 3 HO O Br O O CH 3 H OCH 2 CH 3 HO HO O O CH 3 C. In class I proposed combing Reactant A with Reactant B to form Product C. One functional group in each reactant needs to be protected. Show the reagents needed to carry out the protection and the resulting protected molecule. Then fill in the reagents needed to couple the molecules and remove the protecting groups. Hints: Ketones and aldehydes are often protected as acetals and ketals using diols. Don't forget your protecting groups from peptide and DNA synthesis. Reactant A Reactant B DMT-Cl, py Protected Reactant A H OCH 2 CH 3 DMTO O TsOH (cat) HOCH 2 CH 2 OH Br O CH 3 O O + Coupling and deprotection Please label any steps for sequential reagent additions. 1) Mg 2) 3 3 5 5 6 6 Complete the reactions for parts A and B. Protected Reactant B O OH Cl 3 C excess H 2 O B. ( Tett. Let. 2008 , 49 , 3129) O S O H 3 O + O O OH HS + 4 4 OCH 3 OCH 3 DMT = O intermediate + HOCH 2 CH 2 OH thioacid C 8 H 8 OS Product C aldol condensation or protect as silyl ether if silyl ether remove with TBAF
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Sp08_215_FE_key NC N N H NC A. ( JOC 2008 , ASAP ) The "green" 2,3-diaminomaleonitrile reaction from exams 1 and 2 is back. NC NH 2 NH 2 NC O N C + H 2 O TsOH 16-24 hr HN NH O N H NC CN + + 2 It is time to finish up the mechanism. We left off with Intermediate 7 shown below. Under acid conditions, the isocyanide carries out a nucleophilic attack on the imine. The next step is
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Sp08_215_FE_key - Sp08_215_FE_key I(36 points Complete the...

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