Question

(a) (6 pts) The MO energy diagram for cyclobutadiene is shown below. Fill in the electrons for the neutral compound. Does cyclobutadiene react like a cation, anion or radical in reactions? Explain your answer in 20 words or less. 12 — (b) (9 pts) For the compounds shown below, give the IUPAC names and explain how could you distinguish the two compounds using H and proton decoupled 13C NMR. and Compound A Compound B

Answer 1

a cyclobutadiene The mo energy diagrams for wyclobutadiene iz shown belons T - 74 E q 7 t Tz Am Its a Anti-unmatic systey and this is not its stable form. To gain stability it tengthening two of its opposite bond and beume the Non-arnatic system. Anti-aromatic Won-Aromatic The non onomastic tom is quite stable and will not react with the other compound. Thus it will not react readily under normal condition 1,2,3-trimethylbenzene HNMR: One 3H singlet One 6H singlet One 24 doublet One IH & triplet 1,3,5-trimethylbenzene One 3H singlet One 6H singlet One 34 singlet

- 13 HORT 136 NMR Two sp3-e peak at around f=70ppm One spucpeak at around &= 80 ppm for three methyl solod acolo s obitudalon groups sib your om all Timot olditz ti tonet bro oba stom-stroll out bris brod to go to arst procardipood tiptilidite amp - mod