Talk:Mod:hcn06report1

Part 1.1 Structures and energies for 1 and 2 are fine. Why is the exo isomer more stable? You are right that the orbital coefficients help determine which atoms are involved in bonding, but the usual explanation for the endo-selectivity requires consideration of atoms not involved in forming bonds…. Your energies and structures for 3 and 4 are also fine. What are the exact features in its structure that lead to 3 being higher in energy than 4?

1.2 Hard for me to judge your structures without being able to rotate them… Explanation for sterecontrol with 5 is basically correct. Your lowest energy structure for 7 is fine also – but what is the key mechanistic difference between its reaction and that of the Grignard with 5?

1.3 Energy for structure 10 is high – because the 6-ring is in a boat conformation? It is possible to find a carbonyl “up” structure with the 6-ring in a chair. Why (in structural terms) is the alkene “hyperstable”?

1.4 First structure looks like the rings are boats, not chairs. What about other conformations for 13 and 14?

1.5 You’ve given structures and orbitals, but unfortunately you haven’t calculated (or discussed) the IR stretching frequencies….

Mini-project: Yes, 1H NMR would tell you whether the “correct” alkene had been epoxidised…but HOW exactly? You haven’t calculated/compared the 13C for the isomers, unfortunately..

Overall – the first parts were mostly OK, although hard to judge because of the lack of rotatable (Jmol) structures). The mini-project is far from complete unfortunately – you’ve optimised the two structures, but not much else.