Homework 5 Organic Chemistry MCAT Review Summer 2012 Brent Iverson

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1 omework 5 rganic Chemistry MCAT Review Summer 2012 ent Iverson 1

2 1. For the following reactions, draw the predominant product or products. When a new chiral center is created, mark it with an asterisk () and if a racemic mixture is produced, you must write "racemic" under your structure. If an E,Z mixture is produced as the result of a dehydration step, write E,Z mixture, but you only have to draw one isomer, not both. These directions are different than you may have seen before, and are intended to make it easier for you. You should read them again so you know what we want. No dehydration here because no acid/heat treatment E,Z Mixture E,Z Mixture 1.0 eq. Na 1) 0.5 eq. LDA (No acid or heat) 1) catalytic Na 2) 3 / Δ 2) 3 / Δ N / N 1) 2) 3 1) 2) 3 2

3 2. For the following reactions, draw the predominant product or products. When a new chiral center is created, mark it with an asterisk () and if a racemic mixture is produced, you must write "racemic" under your structure. If an E,Z mixture is produced as the result of a dehydration step, write E,Z mixture, but you only have to draw one isomer, not both. These directions are different than you may have seen before, and are intended to make it easier for you. You should read them again so you know what we want. 1) 1.0 eq. LDA 2) 1.0 eq. LDA 3) 3 (Mild acid) no heat 1) 0.5 eq. NaEt 2) 3 (Mild acid) no heat 1,4 addition 1.0 eq. Na excess 2 Cr 4 (ot; thermodynamic control) (Cold; kinetic control) 1,2 addition cat. 2 S 4 excess 3

4 3. Fill in the boxes with the predominant product formed under the reaction conditions. If a new chiral center is formed in a racemic mixture, put an asterisk () next to it and write "racemic". If there is an aldol reaction on this page D NT DEYDRATE IT!!! racemic 1) NaB 4 2) 2 cat. Na 2 Cr 4 1) 2) mild 3 Mg racemic cat. Ph 3 P C Z product 4

5 4. Fill in the boxes with the predominant product formed under the reaction conditions. If a new chiral center is formed in a racemic mixture, put an asterisk () next to it and write "racemic". 0.5 eq. NaEt Mild 3 No heat 1) Strong 3 + C 2 2) eat (Δ) 1) Mg 2) 3 5

6 5. Fill in the box with the product or products that are missing from the following chemical reaction equations. When a racemic mixture is formed, you must write "racemic" under both structures EVEN TUG YU DREW BT STRUCTURES. C N 3 heat S 2 1) CuLi 2 2) 2 2 eq. N 1) Mg N 2) / 2 1) LiAl 4 2) 2 N 6

7 6. Fill in the box with the product or products that are missing from the following chemical reaction equations. When a racemic mixture is formed, you must write "racemic" under both structures EVEN TUG YU DREW BT STRUCTURES. Note: in principle, this could react on either side of the carbonyl, but due to accessibility, i.e. the methyl group is more accessible, reaction is always observed at the methyl group in these reactions. aloform reaction 1) Na / excess 2 Cu + Li 2) 3 + C 2 -P(Ph) 3 1. ( ) 2 CuLi 2. 2 S 2 C 2 2 / Pd (1st semester) 1) LiAl 4 2) 2 N 3 heat N 2 7

8 7. For the following reactions, draw the predominant product or products. When a new chiral center is created, mark it with an asterisk () and if a racemic mixture is produced, you must write "racemic" under your structure. If an E,Z mixture is produced as the result of a dehydration step, write "E,Z mixture", but you only have to draw one isomer, not both. These directions are different than you may have seen before, and are intended to make it easier for you. You should read them again so you know what we want. 1) 1.0 eq.naet 1) excess LiAl 4 2) 2 2) 3 (mild acid, no heat) 2 (racemic) 1) 1.0 eq.naet 2) 1) excess LiAl 4 3) 3 (stronger acid, with heat) (racemic) 2) 2 (racemic) ardest problem: ow many different stereoisomers are created in this reaction? 6 (There are two meso compounds) 8

9 8. Fill in the boxes with the predominant product formed under the reaction conditions. If a new chiral center is formed in a racemic mixture, put an asterisk () next to it and write "racemic". If ortho/para products are created, you must draw both. C 2 2 Cr 4 hν 2 Al 3 2 Fe 3 N 2 racemic N 3 2 S P 2 2 Ni N 2 NaN 2 N 2 KI KCN CuCN I CN 9

10 9. For the following reactions, fill in theboxes with the predominant product or products. When ortho/para products are both produced, you must draw both. When a new chiral center is produced, put an asterisk () next to it. If a racemic mixture is produced, you must write racemic. N 3 N 2 2 N 2 2 S 4 Ni 2 Fe 3 NaN 2 / CN KCN N 2 CuCN Mg / ether (yes, this works) 3 (strong with heat) 2 Cu Mg 1) C 2 C 2 2) 3 (mild) 1) 1.0 Eq. LDA 2) N 2 N 3 2 S 4 2 N 10

11 10. For the following reactions, fill in theboxes with the predominant product or products. When ortho/para products are both produced, you must draw both. When a new chiral center is produced, put an asterisk () next to it. If a racemic mixture is produced, you must write racemic. N 3 / 2 S 4 N 2 2 N 2 / hν C 2 S 3 N 3 / 2 S 4 2 N S 3 2 Fe 3 C 2 2 Cr 4 racemic C 2 2 Cr 4 11

12 11. For the following reactions, fill in theboxes with the predominant product or products. When ortho/para products are both produced, you must draw both. When a new chiral center is produced, put an asterisk () next to it. If a racemic mixture is produced, you must write racemic. N 2 2 / Fe 3 N 2 N 2 N 2 2 / Fe 3 N 2 N 2 2 / Fe 3 Assume only one atom adds 2 / Fe 3 12