Talk:Mod.1jlm07

Cyclopentadiene. Good results and discussion. Could you show a picture of the transition state? Does this give you any ideas for module 3?

Prolinol: Nice results. Again, nice diagram showing the transition state for Me transfer? Again, ideas for module 3?

Molecule 7 has an energy of 690.820Kcal/mol? Wow. Did no alarm bells sound for this (entirely unreasonable) result?

Taxol: Molecule 9 has two errors. The stereochemistry of the alkene (the C-H should be on the same face as the cis CH protons of the rhs ring junction) and the rhs ring should be chair rather than boat. Same true for 10. Lack of attention to detail let you down here. Good discussion though.

Dichlorocarbene addition: Your orbitals look quite wrong. Most of the time the program does seem to produce correct answers, but sometimes people report random orbitals (the program was updated just before the course, and we suspect there may be a random bug in it somewhere). But again alarm bells should have sounded! for example, none of your orbitals is a C-Cl sigma *, even though you discuss this orbital! Did you re-optimize the geometry after the MM2 at the PM6 level? Good IR results, and nicely presented as spectra! You could have discussed the shifts in the vibrations more though.

Project: Good overall, but the first point to pick up is your statement "Note how the energies of these two are very close, hence the thermodynamic favourability to exist in a 1:1 ratio". Actually, the two energies are 48 kJ apart, and if you plug this into ΔG = -RT Ln K, you get nothing like a 1:1 ratio! Oops! 13C however was very well done. Baffled however by your assertion of "The latter was returned as finished but did not actually give an optical rotation result. This suggests that, since the chiral centers where making up a cyclopropane ring and a cyclopentane ring, there is too much rigidity within the molecule to be able to rotate" This makes no sense. If the molecule is chiral, it WILL return an optical rotation. I suspect you simply did not locate this value in the output of Gaussian!! It does not display in Gaussview and you have to inspect the log file to get it.

Overall, a good effort, but a number of errors (and no alarm bells) does detract.