Talk:Mod1:csy07

Cp: Energies and structures all look good. Just to be clear (you may have understood this already!): note that the calculations you've done by themselves don't tell you what the kinetic product is - it would be perfectly possible for 1 to be preferred thermodynamically AND kinetically. It's the experimental result along with the calculation that suggests that 2 is formed under kinetic control. You haven't explained why 2 is formed faster, though. Also, what structural features are responsible for the difference in bend energies between 3 and 4?

NAD: Good to see you considering several possible starting conformations. It's surprising that your (very slightly) "down" isomer of 5 is lower in energy than the "up" one. This doesn't fit with your explanation that the Grignard co-ordinates to C=O - that would lead to the Me being "down" in the product, which it isn't. Structures for 7 look good; you're right that the C=O is "down" in the lowest energy isomer, and also that the approach of the amine is controlled by sterics. However, avoidance of a clash would make the amine approach on the opposite face to C=O, not the same face as you said.

Taxol: Your two structures are missing the two methyl groups at the bridgehead! Otherwise, the first one is OK, but the second one has the wrong geometry at the trisubstituted alkene. What kind of "ring strain" is incurred if the alkene is hydrogenated?

Carbene: Your IR data are a bit confusing. Why are there three C-Cl values? How do you conclude that the alkene in A is stronger than that in B?

Mini-project: Reasonable choice. I'd worry about the possibility of conformational isomers about the allylic C-C bond. Did you look for these? Your 13C values for the Z-isomer (I can't see the E-ones) really are WAY off - more than I'd expect. I suspect something is not right (correction factor needed?) Ah - just read the end part about the imaginary frequencies!! Yes, these are not proper minima. I'm amazed also that the calculated J-values for the two isomers are so close - are you sure they're right? Any other techniques that you might use to tell them apart?

Overall - quite a mixed bag - you did some good things, but there were also several avoidable errors!