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Talk:Mod:SJN2511

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Q1

  • Correct energies for all compounds.
  • " 1.12 kcal.mol-1"
  • The second half could use some visual aid. I know what you're talking about, but a new reader would have struggled to follow.

Q2

  • "the "up" conformer (9) is less energetically favourable on account of inducing a higher-energy twist-boat conformation on the adjacent cyclohexane ring" the structure you showed actually is chair for the cyclohexane ring, as you pointed out later.
  • "Which may be due to strain on the carbonyl sp2 carbon: even assuming ideal C-Ccarbonyl-C bond angle of 120° (it's usually a bit less), compound (9) exhibits 126°, compared to 120° for compound (10). " It's hard to ignore the opposite trend for the C=C double bond here.
  • Comparing 10 and hydrogenated 10: you must balance the equation!
  • Good explanation of the hyperstability of the alkene.

Q3

  • Your MOs don't have the correct symmetry. There is an error in the software during optimisation process, which you're expected to spotted and rectify or discuss with us.
  • "the LUMO is located around the anti-alkene bond, meaning that this bond will more readily undergo nucleophilic attack instead of acting as an nucleophile. The LUMO+1 and LUMO+2 calculations serve to show that even the chlorine-carbon bond would undergo nucleophilic attack before the endo-alkene bond would" you need to read the reference included in the question.
  • Vibrational frequencies for 12 are slightly off. Again, this has to do with the optimisation process.
  • Bond length discussion missing. The discussion on the interaction between the anti double bond and the C-Cl anti-bonding orbital is too brief.

Q4

  • "diastereoisomery"
  • "the oxocarbenium and dioxolonium conjugated systems"
  • Correct choice of the Me group.
  • B' Jmols are wrong diastereomers. So are D and D'.
  • Much more analysis can be done here For example the difference between MM2 and PM6 results. The energies of intermediates and the diastereoselectivity of the reaction.

Mini project

  • Distinguishing between 5 and 6 is so trivial, it doesn't require computational chemistry. The diastereoselectivity of the reduction (to give either 5 or 6) is worth studying and you were meant to do that.
  • Optical rotation: what you have for 6a is the epimer of 6, not enantiomer. Hence the same sign of rotation for both compounds.
  • I'm not following your HOMO/LUMO argument here. In any case, modelling radical reactions, particularly the transition states, is extremely tricky and require much higher level of theory. Brave attempt though.