Talk:Mod:kl1111syn

MARK: 61

General Comments: You could have added a brief introduction about what methods are you using for this exercise and what are the advantages and disadvantages of the. Very little effort in the second part, next time I advise you to read better the exercises, ask your demonstrators and plan better your work to finish everything.

1.1 Part 1 (45%)

1.1.1 Formation and Hydrogenation of Cyclopentadiene Dimer (10%)- 9

You obtain the correct energies, you could have extended longer the explanation about what the kinetic control involves.

1.1.2 Atropisomerism in an Intermediate related to the Synthesis of Taxol (10%)- 10

You mentioned that 7 conformations may exist, you could have extended a bit more, mentioning which ones and why do you believe so. But well done, obtaining four possible conformations, good job. Your ranking is correct and your discussion about the bonds is good.

Good and complete discussion about the hyperstability.

1.1.3 Taxol NMR - Spectroscopic Simulation using Quantum Mechanics (25%) - 20%

Well done modelling and obtaining both molecules, however, you mention that molecule 18 was chosen for the spectroscopic analysis, you should have provided a reasonable explanation for this. In the discussion of you HNMR you mention that some shifts are coloured in red, this is not the case in your graph, I am going to have faith in you and think that these are your original results and you didn´t copy the text. In the CNMR you have some peaks whose deviation from literature are markedly higher than the others, these correspond to atoms with have special features, you should have discussed this. You cannot be awarded with the full mark in this exercise, even though you have done a good job obtaining the spectrum and the literature results.

1.2 Part 2 (55%)

1.2.1 The Crystal Structures of the Shi Catalyst and the Jacobsen Catalyst (5%) - 5 Good work, well done finding the structures and very complete discussion.

1.2.2 The Calculated NMR Properties of the Epoxides (5%)- 5 Good results and well done finding the experimental NMRs, the discussion a bit vague, but good work.

1.2.3 The Assignment of the Absolute Configurations for Alkenes 2 and 4 (35%) - 10 You have only calculated the OR for one of the epoxides, you should have done this exercise for two epoxides. Also, you haven't calculated the enantiomeric excess for the epoxides, which was the main problem in this exercise. But even though you weren't asked,you have discussed the different transition states, so I am going to award you with 10/35%.

You can read this at the beginning of the exercise: "You will need therefore to model two epoxides from the following selection of four. Choose any two epoxides you prefer, e.g. you could compare the computational data with the obtained data for the epoxides you synthesised in the lab."

1.2.4 NCI Analysis for the Transition State and QTAIM - 2/6

Very poor discussion.

1.2.5 Suggesting new candidates for investigations - 0 Not done

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