MS 8115 - Explain The Justification They Provide For The Observed Stereochemistry In The Product - Engineering Assignment Help

Assignment Task

1. (12 total marks) This question refers to Fawwaz’s paper presentation: “Stereoselective Formal Hydroamidation of Si-Substituted Arylacetylenes with DIBAL-H  and Isocyanates: Synthesis of (E)- and (Z)-α-Silyl-α,β-unsaturated Amides” Lee, H.; Cho, S.; Lee, Y.; Jung, B. J. Org. Chem., ASAP. 
“Stereoisomerically Pure Trisubstituted Vinylaluminum Reagents and their Utility in  Copper-Catalyzed Enantioselective Synthesis of 1,4- Dienes Containing Z or E Alkenes” Akiyama, K.; Gao, F.; Hoveyda, A.H. Angew. Chem. Int. Ed. 2010, 49, 419 –423. 
In the Angewandte paper, Hoveyda et al. use Eisch’s approach to control the double bond  geometry following hydroalumination by changing the solvent of the reaction, as illustrated in  Scheme 3 (seen below, in part).
a. Draw a plausible arrow-pushing reaction mechanism for the formation of both 2 and 3 in the graphic above? (4 marks) 
b. Explain the regiochemistry of the addition of H-Al across the C/C triple bond, and justify  why the observed regioisomer is the only one seen. (2 marks) 
c. Which stereoisomer is the kinetic product? Which is the thermodynamic product?  Justify this by using the experimental evidence above. Draw an energy diagram for each  transformation to illustrate your answer. (4 marks) 
d. Is THF the only solvent that would work to enable the selective synthesis of 2? If not,  what other solvent(s) could you use in its place? (2 marks)
2. (12 total marks) This question comes from Enea’s paper presentation: “Substrate Controlled Regioselective Bromination of Acylated Pyrroles Using  Tetrabutylammonium Tribromide (TBABr3)” Gao, S.; Bethel, T.K.; Kakeshpour, T.;  Hubbell, G.E.; Jackson, J.E.; Tepe, J.J. J. Org. Chem. 2018, 83, 9250−9255. 
Figure 2 in the paper (seen below, in part) shows the innate preference for electrophilic  aromatic substitution patterns on monosubstituted pyrroles with either electron-withdrawing  (W) or electron-donating substituents (D). 
a. Draw one 2-substituted pyrrole with an electron-withdrawing substituent and another  with an electron-donating substituent (i.e. pick an EWG and an EDG to use for the rest of  this question). (2 marks) 
b. What is the major product formed when each of the molecules from 2a (above) are  exposed to acetyl chloride and AlCl3? (Two reactions, one major product in each.) (4  marks) 
c. Using mechanistic drawings (including comprehensive resonance structure drawings) and  energy diagrams to explain why the products observed are the ones formed preferentially in each case. (6 marks)
3. (12 total marks) This question comes from Nicola’s paper presentation: “Stereoselective Synthesis of Terminal Monofluoroalkenes from Trifluoromethylated  Alkenes” Poutrel, P.; Pannecoucke, X.; Jubault, P.; Poisson, T. Org. Lett. 2020, 22,  4858−4863  
The authors of this paper claim that the stereochemistry observed in the product is the result of  a stereoselective elimination of HF. They propose a mechanism and transition state for this step  in Scheme 3. 

a. Explain the justification they provide for the observed stereochemistry in the product. 
b. Can this analysis be justified by any of the substrates in the scope scheme (Scheme 1)?  Discuss that.
c. Could you design an experiment (or series of experiments) to test their hypothesis  regarding how stereochemistry is determined for the reaction? (4 marks)  

d. Can you think of another plausible explanation for the observed stereochemistry?

This MS 8115 - Engineering Assignment has been solved by our Engineering Experts at My Uni Paper. Our Assignment Writing Experts are efficient to provide a fresh solution to this question. We are serving more than 10000+ Students in Australia, UK & US by helping them to score HD in their academics. Our Experts are well trained to follow all marking rubrics & referencing style.

Be it a used or new solution, the quality of the work submitted by our assignment experts remains unhampered. You may continue to expect the same or even better quality with the used and new assignment solution files respectively. There’s one thing to be noticed that you could choose one between the two and acquire an HD either way. You could choose a new assignment solution file to get yourself an exclusive, plagiarism (with free Turnitin file), expert quality assignment or order an old solution file that was considered worthy of the highest distinction.