Talk:Mod:sb1106

2 Energies reported are spot on. Cpd 1 is actually the exo dimer and 2 is the endo dimer, but assuming you meant it to be the other way around, the arguments are correct.

3 Energies are good as is the explanation for the observed stereoselectivity.

4 The calculation for the CO-down isomer is good, but it appears that your CO-up isomer has found its way back into the CO-down conformation. The CO-down is in fact the most stable isomer (this is probably why your molecule readjusted itself!). Following on from this, the reasoning is logical.

5 The calculations are mostly very good, you may have missed the optimal H-bond for one of the isomers (cis-ax). Analysing the structures it seems as though all of the isomers could actually react (i.e. have a conformer with the appropriate angle and distance of approach as you discussed); this is contrary to what is reported in the literature report, although the calculations they have done are rather inconclusive. It seems that there is more to the problem than can be explained by their reasoning.

6 The MO diagrams are well presented; calculations and stretching frequencies are good, but the C-Cl bond is expected to become stronger when the exo-double bond is hydrogenated (in the diene, this double bond donates from its pi electron cloud into the C-Cl sigma* antibonding orbital weakening it and this isn’t possible once it is hydrogenated).

MP Great choice for your project: The calculated vs. experimental spectroscopic data is very well presented. I think you have confused nOe with something else: the nuclear Overhauser effect relates to nuclear spin interactions between proximal nuclei; it is used to elucidate the structure of complicated (particularly fused/polycyclic) systems. The authors of the Nazarov cyclization paper used this effect to show which compound they had made, since there is an interaction between the 1H nuclei of the gem-dimethyl groups on the bridgehead and the 1H nuclei attached where the rings are fused.