First Midterm. Ian R. Gould PRINTED FIRST NAME. noman 2 /17 1 /10. acidity 3 /39. reactions 4 /21. bonds 5 /12. acidity 2 6 /40. synth 7 /36.

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1 EM 234, Spring 2011 First Midterm Ian R. Gould PRITED FIRST AME ASWER PRITED LAST AME KEY ASU ID or Posting ID Person on your LEFT (or Aisle) PRIT YUR AME EA PAGE! READ TE DIRETIS AREFULLY! USE BLAK PAGES AS SRAT PAPER work on blank pages will not be graded. WRITE LEARLY! MLEULAR MDELS ARE ALLWED D T USE RED IK D'T EAT, USE MM SESE! Li Be B F e a Mg 1 /10 noman 2 /17 acidity 3 /39 reactions 4 /21 bonds 5 /12 acidity 2 6 /40 synth 7 /36 mxn Extra redit /5 e Al Si P S l Ar K a Sc Ti V r Mn Fe o i u Zn Ga Ge As Se Kr Rb Sr Y Zr b Mo Tc Ru Rh Pd Ag d In Sn Sb Te I s Ba Lu f Ta W Re s Ir Pt Au g Tl Pb Bi Po At 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 Aromatic Ar mainly usually strong R R 2 R Person on your RIGT (or Aisle) 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-bu/me ~2.7 Approximate oupling onstants, J (z), for 1 MR Spectra Alkyl 3 Y > 2 Y > 1 Y Alkyl ~2 ~10 ~ ~8 ~2 ~7 3 Y > 2 Y > 1 Y 0 0 Aromatic R 2

2 EMISTRY 234, Spring 2011 MIDTERM #1-2 - AME Question 1 (10 pts.) Give the IUPA name for the following compound. Be sure to use cis/trans, E/Z or R/S where appropriate. 3-methylhept-(3Z)-en-6-yn-(2S)-ol Question 2 (17 pts). Which is the stronger onsted acid, A or B (ignore keto-tautomers). Give a BRIEF explanation and support your assignment using appropriate drawings of the conjugate base anions A B B When deprotonated, the conjugate base alkoxide anion from A has fewer resonance contributors, the non-bonding electrons not as delocalized, they are higher in energy, the anion is less stable, this A is the weaker onsted acid. The conjugate base alkoxide from B has more resonance contributors, the non-bondong electrons are more delocalized/stabilized, B is thus a stronger onsted acid

3 EMISTRY 234, Spring 2011 MIDTERM #1-3 - AME Question 3 (first part, 18 pts.) For each reaction 1) Provide the missing major organic product, ignore sterochemistry at asymmetric centers 2) State whether each reaction is an Addition, Eimination, Substitution or Rearrangement 3) State whether each reaction is Reduction, xidation or either a) P/ 2 l 2 elimination and oxidation b) a/ 3 (l) addition and reduction Question 3 (second part, 7 pts.) Provide the missing reagents/conditions D T STATE whether the reaction is Addition/Eimination/Substitution/Rearrangement D T STATE whether each reaction is reduction/oxidation/neither c) gs 4 / 2 S 4 / 2 Question 3 (third part, 14 pts.) GIve the major organic product of the following reactions D T STATE whether the reaction is Addition/Eimination/Substitution/Rearrangement D T STATE whether each reaction is reduction/oxidation/neither c) l 1. Excess 3 2 Mg d) 1. /RR 2. Mg.TF

4 EMISTRY 234,Spring 2011 Midterm #1-4 - AME Question 4 (21 pts.) Several of the - bonds in the provided structure can be made in a Grignard reaction. Provide the structure of the Grignard reagent AD the structure it would react with (assume an acid workup step. i.e. do not include the 3 + ), and indicate LEARLY the - bond you are making in each reaction. Mg + Mg + + MeMg + MeMg Question 5 (12 pts). Which is the stronger onsted acid, A or B? Give a BRIEF explanation that includes a discussion of both the inductive and the resonance substituent effects. You do T need to draw any chemical structures or include any curved arrow-pushing unless you would like to, all points are for the explanation, words are sufficient to answer this question. A 2 withdrawing B donating onsted acidity is determined in this case by the stability of the conjugate base anions. The subsituent in A stabilizes the anion BT by the inductive effect and also by the resonance effect. The substituent in B stabilizes the base anion by the inductive effect, but destabilizes the anion via the resonance effect. The resonance effect dominates over the inductive effect, the bas anion from B is less stable, is harder to form, the acid B is weaker and the acid A is stronger. 5 pts Extra redit. The "slime" and "silly putty" polymers that are made by combining starch and white glue and similar compounds are held together by what kind of bonds? (circle one) hydrogen-bonds π-bonds σ-bonds multiple-bonds

5 EMISTRY 234, Spring 2011 MIDTERM #1-5 - AME Question 6 (40 pts.) Show how you would synthesize the target componds on the right from the starting compounds on the left. Show reagents and conditions, and the structures of important intermediate compounds. Do not show any (arrow pushing) mechanisms. a) 2 2 /Lindlar 1. Excess a 2 /heat a b) BS/hν Mg K + -t-bu /RR Mg.TF

6 EMISTRY 234, Spring 2011 MIDTERM #1-6 - AME Question 7 (36 pts). READ TIS QUESTI AREFULLY! For EA reaction, give a complete cuerved arrow pushing mechanism, and. 1) Show ALL important resonance contributors for all intermediates. 2) Add non-bonding electrons and - bonds to the line-angle structures as required. 3) Indicate the Lewis acid/lewis base (LA, LB) at each step as appropriate, and whether they are also ønsted acids/bases (LA/BA, LB,BB). LA/BA l cat. / 2 a) LB/BB 2 : : LB/BB LA/BA b) LB/BB 2 S 4 cat. 2 LA/BA LB/BB LA/BA