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MT2Key_Wi05 - NU Winter 2005 MTZ 2 1(20 pts For a gives the...

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Unformatted text preview: NU, Winter 2005, MTZ 2 1. (20 pts) For a, gives the IUPAC name of the structure shown, noting the correct stereochemistry in the name. For b-e, complete the following reactions, be careful to give all the major carbon-containing products, starting materials, or reagents. Clearly indicate any stereochemistry when relevant. If there is no reaction, say so. am ,. $0M _» P ”Vt/i?) baa/we 07L j’akw —/ qr ’NIL’o b a“ 0“. n ar:~m,a 4w: 7\ i "w ;\ b) > a L,g‘rt '71AJQ ill W: ,m (,7) mag/y 5i“; 9!) 110%, )A 71>Lot'3u)ll OM E0) 13’) Mom)“ (“at”); A Ho/>#OH \ ————-—————-———> O gilt, c) a) :rt\‘%/ 3A HofOH A) LU @k )1: 7’) NAME but»? 5’.) 03, (if, 32‘1””) <6?) Hygf mange, A.) KLJI/ r.[5 (W‘A‘l I 6> [\jL‘ F2 8”“ I} %> PIKLL; (ML 3) l*L\UQ Lent i 1) pin, g )‘l: V o 2 ) krit'll‘UA O 04. g—"Ww L'rm‘tv New? ON A «flow - (tr—W Mat/My“ OIL WW — 0 mm. W 0%’Ww / P—W Walter/“y“, OK \ f, ‘ 6t» 3 l1) _ —————— ) 2:) M ii )A, 2) 3 Kit 4) Katy,“ MAM s... F‘””\ ’[w‘ \M / l» ___x\ i/._— \\ ..—« \ ,._I v/‘W‘ NU, Winter 2005, MT2 _ 3 2. (20 pts) Draw the 7t molecular orbitals of 1,3,5-he4genyl dianion, complete with all the lobes and order them on the energy scales below. Fill the electron into the molecular orbital levels and show the HOMO and the LUMO of this molecule. Relative to 1,3,5-hextriene, how stable do you expect 1,3,5- hextrienyl dianion to be? Use this information and any necessary diagram to determine if the thermal [6 + 6] reaction between cis, cis, cis-l,3,5—hexatriene and cis, cis, cis-l,3,5-hexatriene can occur. What about the thermal [6 + 4] reaction between cis, cis, cis-1,3,5-hexatriene and furan? You can buy the structure of any of these molecules from the instructor for 1 pt each if you don’t know what they are. 1,3,5-hexatriene3fl oh‘m‘w iW~\\ 343‘ V QM) , me [6 <4] -_ Fatima» m (J94 H ocwrt kgtwcé’ . m t . .. ._ , . we NEW“ EVE) WM Hmaw \s c: {Liar ’1 Hi? '1 iiébf/f/TILM, 9 ’ TN Diets—m WMDQLW‘JA Does NAT TAM/5 TM? M770 “WWW Qx'J' NU, Winter 2005, MT2 4 3. a. (4 pts) Using Huckel’s rule only and assume that each compound will take the lowest energy conformation/resonance, classify the following molecules as likely to be planar or non planar. Write your answers below the molecule. If you cannot tell, say so. If a molecule will take an alternate conformation/resonance to be planar, draw that conformation/resonance. 06* Gr W WW\ a?» /"\ M N E 9 N , 1 i Pr wL MN {:QSQ E: j [:13] ‘ w CM'TWW PLMML CMS'TWCLL PLAWL b. (4 pts) Using HuCkel’s rule only, classify the following as—drawn planar molecules as being aromatic, antiaromatic, or neither. Write your answers below the molecule. If you cannot tell, say so. Q.‘ B OH P fl Ar“ r/ W boa; Mm, Mamet. Web Name/t c. (10 pts). Using the polygon rule, draw an energy diagram for the MO’s of the planar cyclopentadienyl radical and the planar cycloheptatrienyl anion. (There is no need to draw the lobes.) Fill the available electrons into the molecular orbital levels and show their HOMO and the LUMO. Are these molecules aromatic, antiaromatic, or neither? What is the mildest agent that you can use to make cyclopentadienyl anion from cyclopentadiene in one step? .,._ 1L MM kLinE Mao to CF 11% 1224+ on But u - @ F/ d 21¢ planar cyclopentadienyl radical "U 61 fi+€® planar cycloheptatrienyl anion ‘. W. WMWL p d) (2pts). Circle the most important resonance in the following pairs: / \\ ., «.\ 99$ NU, Winter 2005, MT2 4. (20 pts) Propose a curved arrow mechanism for the following reaction. Show all the proton transfer steps. 0 QH TsOH, heat / \\ “lpl 11C anionic: oxggCfl is (lHaClqu +he carbowlion 0&5 NU, Winter 2005, MT2 6 5. (20 pts) Suggest a sequence of reactions involving at least one Diels-Alder reaction for the synthesis of the molecule shown below. You may use s-cis—l,3—butadiene and any organic starting materials containing 3 C or less. However, you may not use acetylene as a starting material. You may also use the Swem reagent (dimethyl sulfoxide, N33, and oxalyl chloride), Og/MeZS, NBS, tosyl chloride, pyridine, PCC, mCPBA, peroxide, and any inorganic reagents. Hint: Your life can be a whole lot easier if you think Diels-Alder more than once. I go ‘. 1M4- ILM/ éia—fi 1W, L; vx’: 858‘, l :\ l”? f: a \ __._L——-9 l (C V 1% ,/ Etta \/ M?) In P1» JUL, A ,,|/\/’UOL l "l IL ,J 2 ll L U0), , \ i t 2% och€rg 13M, , Zrt \\ w ‘ (adj/,0 , ’) #8ka 4~ w/WL‘ 97% &/ Mfr, ' l l l! . é—d L/L [JUL Lin im\,~- , L g, arts - 3‘) l1, 3/X K) , ‘1.“ ,H , a f; L\§/f\ _ “1’: 3 B’L‘L—m—Q {1;\‘[/\}/ NW ; T/xme ’5) 2, wt?“ )1\ 1:: /l\ ’A Wt "-l‘P’t3 i, 24¢: ’ x .. bu‘ / ’1‘ - _ /l!\ [JUL 2 WVCAxLA //1\\\//l¢\» INC/hL l l / _~ L l [ [xxx z/L r/ \ “0;, d. l k\/ \ [Jug F l . '1 l I) / N/Malli m 7 NU, Winter 2005, MT2 6. (20 pts) Suggest a sequence of reactions involving at least one Diels-Alder reaction for the synthesis of the molecule shown below. You may use cyclohexene and any organic starting materials containing 4 C or less. However, you may not use acetylene as a starting material. You may also use the Swern reagent (dimethyl sulfoxide, NEt3, oxalyl chloride), Og/Mezs, NBS, tosyl chloride, pyridine, PCC, mCPBA, peroxide, and any inorganic reagents. cu ...
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