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

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
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
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
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
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 05/29/2010 for the course CHEM 215 taught by Professor Koreeda during the Spring '07 term at University of Michigan.

Page1 / 6

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

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online