Talk:Mod:frisbee0702

1.1 Energies are good, as is discussion about thermodynamic vs. kinetic control; the difference in the energies of the hydrogenated dimers is due to differences in bending contributions arising from the environments of the double bonds present.

1.2 The structure of the first example is correct and the reactivity is likewise correctly rationalised, but the second example does the opposite: CO group should point down relative to the medium ring and the reactivity is governed a repulsive interaction between the nucleophile and the carbonyl group, not via coordination.

1.3 The CO-down isomer is indeed the lowest in energy, but your values are a little high; this is probably on account of the geometry of the cyclohexane units which aren’t fully optimised. Hyperstable alkenes are well defined; Bredt’s rule, in fact, applies only to certain bridged systems.

1.4 Energies are excellent. Comment on the selectivity is well rationalised, but in fact by rotation of a few bonds in the different isomers it is possible to justify the molecule reacting via any of them (as opposed to what is stated in the paper). The important factors to consider in this reaction are the distance and angle of attack and the fact that the intramolecular system reacts more quickly than an equivalent intermolecular reaction.

1.5 The LUMO is largely distributed over the exo-double bond, whereas the HOMO is distributed over the endo double bond. This suggests the exo-double bond is more likely to react with nucleophiles and the endo- more likely to react with electrophiles.

MP Calculated chemical shifts appear to be in accord with those reported; when you talk about multiplicity, I think you might mean relative integration. The 13C spectrum obtained was probably done so “decoupled” that is to say no splitting (on account of interaction with 1H for example) is seen. Also it is not common to integrate 13C peaks because the relative intensities are largely dependent on the relaxation times of the nuclei in question and differ depending on the chemical environment. The spectra were nicely presented but perhaps could have been a bit bigger. The discussion surrounding the regioselectivity was good.