Second Midterm. Ian R. Gould PRINTED FIRST NAME 1 / / / / / / /24... Extra Credit /5

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1 EM 234, Spring 2011 Second Midterm Ian R. Gould PRITE FIRST ME SWER PRITE LST ME KEY SU I or Posting I Person on your LEFT (or isle) PRIT YUR ME E PGE! RE TE IRETIS REFULLY! USE LK PGES S SRT PPER work on blank pages will not be graded... WRITE LERLY! MLEULR MELS RE LLWE T USE RE IK 'T ET, USE MM SESE! Li e F e a Mg e l Si P S l r K a Sc Ti V r Mn Fe o i u Zn Ga Ge s Se r Kr Rb Sr Y Zr b Mo Tc Ru Rh Pd g d In Sn Sb Te I Person on your RIGT (or isle) 1 /10... nomen peri3 2 /20... peri 1 3 /16... rxns 4 /23... / 5 /40 retro... 6 /24... peri 2 7 /18... orbital 8 /24... spect Extra redit /5 s a Lu f Ta W Re s Ir Pt u g Tl Pb i Po t Rn amine alcohol (δ, ppm) small range range of values broad peak R 2 R R R 3300 variable and condition dependent, ca. 2-6 δ peaks romatic r mainly usually strong R R 2 R Xe Infrared orrelation hart Total (incl Extra) / R Interaction Energies, kcal/mol Eclipsing / ~1.0 /Me ~1.4 Me/Me ~2.6 Me/Et ~ R broad with spikes ~ broad ~ R2 broad ~ (cm -1 ) MR orrelation harts 2 X R 2 R X Gauche Me/Me ~0.9 Et/Me ~0.95 i-pr/me ~1.1 t-u/me ~2.7 pproximate oupling onstants, J (z), for 1 MR Spectra lkyl 3 Y > 2 Y > 1 Y lkyl ~2 ~10 ~ ~8 ~2 ~7 3 Y > 2 Y > 1 Y 0 0 romatic R 2

2 EMISTRY 234, Spring 2011 MITERM #2-2 - ME Question 1 (10 pts.) Give the IUP name for the following compound. e sure to use cis/trans, E/Z or R/S where appropriate. r 4 3 Et Me bromo-3-ethoxytoluene Question 2 (20 pts) In this question you will be determining whether the provided reaction is allowed or forbidden heat F 3 F 3 F 3 F3 a) give the curved arrow-pushing that describes the bond-making and bond breaking b) does the RETI SW, proceed via a conrotatory or disrotatory ring-opening? answer conrotatory c) how many electrons are involved in the transition state for the provided reaction? answer 6 d) Give a justification for whether the RETI SW is allowed or forbidden. Your answer must include the following terms: uckel and/or Mobius, conrotatory and/or disrotatory, aromatic, low energy and high energy transition state the reaction shown has 6 electrons and proceeds via conrotatory ring-opening, which has a high energy Mobius transition state compared to the corresponding disrotatory transition state,which would be uckel and aromatic, the reaction is thus forbidden Extra redit Question (5 pts.) Which important type of biological molecule has this cis-enediyne been shown to damage? proteins lipids carbohydrates

3 EMISTRY 234, Spring 2011 MITERM #2-3 - ME Question 3 (16 pts) Give the major organic products of the following reactions, indicate both the relative and the absolute stereochemistry. 3 a) r / 3 (solvent) (thermodynamic control conditions) (±) 1. r 2 /hν 2. K - -t-u Et b) 3. MP 4. a - Et/Et (±) Question 4 (23 pts) a) Give the products of the following two iels-lder reactions (be sure to specify both absolute and relative stereochemistry as appropriate). 2 2 F 3 Δ (±) F 3 Δ (±) F 3 F 3 b) raw a reation energy diagram for these two reactions, clearly indicating which diagram refers to reaction and which to reaction. lealy indicate the activation energy for the reactions and. ssume both reactions have similar exothermicities, indicate the exothermicity. relative energy E a E a exothermicity reaction coordinate

4 - 4 - EMISTRY 234, Spring 2011 MITERM #2 ME Question 6 (24 pts). Give the LLWE product of the following cycloaddition reaction heat R a) Give the curved arrow-pushing that describes the bond-making and breaking. b) Redraw the cation and give a pictorial representation of the wavefunction of the M TP F TE STRUTURE bonding c) Redraw the dicyanoethylene and give a pictorial representation of the wavefunction of the LUM TP F TE STRUTURE bonding d) Give a brief justification for the structures of your allowed product, you must include the following terms in your justification: suprafacial and/or antarafacial, M, LUM, bonding and/or anti-bonding the LLWE product of the reaction must have two bonding interactions in the transition state, consideration of the wavefunctions of the M and the LUM indicates that suprafacial/suprafacial reaction is allowed, thus the 2 - groups start cisand are on the same side in the product, and the two Me-groups on the outside of the cation end on the same side in the product Question 7 (18 pts). For the provided structure: a) Give all reasonable resonance contributors and indicate the hybridization of the carbon and T nitrogen atoms sp2 sp sp b) Redraw the structure and draw a schematic representation of the wavefunction of the LUM on TP of your re-drawing of the structure

5 EMISTRY 234, Spring 2011 MITERM #2-5 - ME Question 5 (40 pts.) Show how you would make the target componds on the right from the starting compounds on the left. Show reagents and conditions where appropriate, and the structures of important intermediate compounds. o not show any (arrow pushing) mechanisms. two possible syntheses are shown here, there are others a) S, hν MP Ph Ph r Ph a 1. Ph a PhMgr 2. 3 Ph 1. g(c) 2 / 2 2. a 4 Ph P Ph b) 2 3 S/hν 2, Pd/ r K -t-u heat

6 M 234, Spring 2011, MITERM #2-6 - ME Question 8 (24 pts.) Provided are spectra for a compound with molecular formula a) Give the degrees of unsaturation 4 degrees of unsaturation b) n the infrared spectrum, indicate the peaks that identify the functional groups in the molecule (including (sp 3 )-). Indicate T the functional group, and where appropriate, the specific in the functional that corresponds to the peak sp sp 3 c) draw the structure and clearly indicate which hydrogens correspond to which signals in the proton nmr spectrum LY 6 3 peaks here doublet multiplet 2 doublet 1 multiplet

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