Chem 112B-Spring 2008-Midterm 1

Chem 112B-Spring 2008-Midterm 1 - Chemistry 1123: Midterm...

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Unformatted text preview: Chemistry 1123: Midterm 1, Thursday March 6, 2008 Name: KCé} U CSID .° ' GSI: Question 1 (35 points) Y Question 2 (25 points) Question 3 (25 points) Question 4 (25 points) Question 5 (30 points) Question 6 (35 points) Total —————————— —— —/175 points Question 1 (a) Propose reagents and reaction conditions for the following transformation, and a name for the functional group in the product. (5 points) HL/V/VHZ NH2 0 N’ New _ A | functlonal [,7de iont / H / H group. ———> ,N o ,N otsto ‘Sto (b) Propose reagents for the following transformation and a name for this type of reaction. (5 points) léoH, #20 A N/NHZ I CH3 ,” l“ O: ‘ 0: ~ [3‘0 ,S~o Ph Ph (c) Propose reagents for the following transformation and a name for this type of reaction. (5 points) Name (d) Provide reagents and conditions for the following reaction, and name the new functional group in the product. (5 points) 0 c 4/000 New 0 functional . 0 group “V'Qflll/Zt O (e) Propose reagents for the following transformation and provide a mechanism for this reaction (use R to abbreviate as necessary). (15 points). O O I” 0: ~ ,S~o Ph (700 Mechanism: Cl bfi Cl “‘30; (la 9 o l \ No! ~ c! /K'/"' c; - ’4 0 -———-> o a, K o H" r” I 0 AL) '0 A; C/ 0% p \O—H' R a a db w ’K/OH a an F #LCI + #C/ (x a'H ole K'kc/ + co; rco f6 ‘ v u I WW M v m. “’3? Ge 0 C] e L7 0 0/ lg‘c/ Te , C ' v H \7. L .4 I ‘3 3\ Cl \0 a ‘ L >5 @ h ' L0H 0‘” 016 H ._——7- x C] ,L + , 5‘01 0 ~ ¥ w x“ W \_ K/uxc/ + /+c/ C] (‘i v >\r 4 C l 0‘6 \P/U 0' cl 0 /—? 7 Ci 0’ ~ cl \/ BJLO [it/1 L)! ’L/‘J\ \cl o’r‘cl L“ Cl {L‘ ___1 Cl {C‘Lfl‘ earl” " T" ‘L if” T“ ‘ C‘ .1 EDGE Cle \l/ o Question 2 (a) Discodermolide (shown below) is a famous anti-cancer compound that succeeds in curbing cancer where many others fail. The aldol reaction and the aldol condensation are two reactions that may be applied in building discodermolide. Circle three examples of either one of these reactions in discodermolide. (Hint: the aldol or aldol condensation reactions may be followed by oxidation, reduction or protection reactions). (9 points) Discodermolide (b) Nature uses malonyl CoA (A) and acetyl CoA (B) to make the products of aldol reactions and aldol condensations using Claisen reactions. Propose how you would make C using A and B. (16 points) Multi Ie U i stelfs OH OH OH R-s OH Me SR MeWOH Malonyl CoA Acetyl CoA I (A) (B) c 1/ louse, 06 w [as/K ] ’r 7' a F'S’LK [I [414ng 2Jg1>+ Question 3 (a) Predict the products of the following reactions. (10 points) 0 (b O—MgBr 0 @firome (excess) l ’ Me @ (walkway) A o (D MgBr @OMe (excess) (@ WM I; W?) B (b) Explain using a mechanism why the expected products you indicated in part (a) for A and B were obtained (15 points). \/ bill/17115614 0% A 1%: :thdml im+crrwd44¥c ' m/rid 3M ¢Mtfiéfl 0% Gfioymrd Bqu’G , a \j g9 )k eg/Mj—O 2v [7% 0M “(j C’ / Gina 0 -—> F” A?) no AW 92/410?th 1/?) \Z Erma 0 £9 (/mgrk— Ur ) W‘fith occur: W 0H “‘50 Question 4 Propose a synthesis of C and give appropriate reagents starting from A and B given that an amide bond is formed first. (25 points) OMe Na H ( baSeB o: ‘ ~ u z N I 0M6 G o m 0,, Me I..— c 6*] E4126 We Question 5 Propose a mechanism for the formation of A below using a Robinson annulation. What is the identity of C? (30 points) 0 Ph 3 VLCH O A Ph :5 Cb W569 0"» r) o (\S/ I v... o (W CH5 9/ l/ (a yo Question 6 (a) Propose a synthesis of C from A and B using the following sequence of reactions: 1) Baeyer Villiger, 2) Claisen condensation, 3) ketal hydrolysis, 4) Retro aldol and 5) aldol condensation. You may use any other transformations you deem necessary. Indicate the necessary reagents and conditions (25 points). 0 O 0 Me Multiple 0 Steps ph ____._> 0 )L Ph {,0 Me O A B B c 6 WA M a (I; / CW’U U 0 a—— I h o H o ( M I (a . mm 7 u 1%“ 5...? ‘0 (us-Me) fits/er / aw: F“ 6 ° l a , , a 0 CWMUV'Sc! hm) I A (“in flag.) 0 (b) Explain with a mechanism using any intermediate from part (a) why D might be expected as a by-product of this reaction. (10 points) o a I 17;“:{14/ 3 bszf z I o C a 6 01* 5 1' 1 halo g’flml ———> a ——-> F9 0,79‘7 r“ ((7 r‘ »€I~ fl 3" (W 11/ b (on, 4' 3 0 d 0// o e o O ...
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Chem 112B-Spring 2008-Midterm 1 - Chemistry 1123: Midterm...

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