Hour Test Three S12 hint key PDF

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Chemistry 354: Spring 2012 Hour Test Three March 26 2012 This test has 9 pages including this cover page. You have 50 minutes to complete this test When drawing structures you can use any convention (bond line, condensed etc) EXCEPT when specifically asked otherwise. Be consistent with the convention you choose and include resonance structures where necessary.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ I hereby pledge that I have neither given nor received unauthorized aid on this test.

________________________________ Signature ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Section I. Multiple Choice (10) II. Transformations (8 of 11) III. Mechanism (2 of 3) IV. Synthesis

10 48 30 12 Total 100

____ ____ ____ ____ ____

Section I: Multiple Choice – Choose the most appropriate answer for each question. (1pts each)(all 10) 1. What is the IUPAC name for the following compound?

O

A) B) C) D) E)

2-methyl-5-heptanone 7-methyl-4-octanone 6-isopropyl-4-octanone isobutyl propyl ketone 1,1-dimethyl-4-heptanone

2. Which reagent(s) could NOT be used to carry out the following transformation? O

A) B) C) D)

Zn(Hg), HCl LiAlH4, ether HSCH2CH2SH, BF3; then Raney Ni (H2) NH2NH2/KOH/heat

3. The 1H NMR spectrum of a compound with formula C 7H14O shows two signals. Which one of the following is a possible structure for this compound? A) 2-heptanone B) 3-heptanone C) 2,4-dimethyl-3-pentanone D) 2,2-dimethyl-3-pentanone E) Two of the above 4.

What is the common name for the following compound? F

O

OH

-fluorobutanoic acid B) β-fluorobutanoic acid C) β-fluorobutyric acid D) -fluorobutyric acid E) 3-fluorobutyric acid

5. What is the correct structure for succinic acid O OH

O

O

O

O

O OH

HO

OH

HO

OH

I

HO

II

III

O

IV

6. Which of the following is a hemiacetal?

7. Which of the following gives the greatest percentage of hydrate (gem-diol) when dissolved in water? A.

butanal B.

2,2-dichlorobutanal C.

3,3-dichlorobutanal

D.

4,4-dichlorobutanal

8. What is the IUPAC name for the following compound? O

Cl

A) -methylvaleryl chloride B) 2-methylpentanoyl chloride C) 3-methylhexanoyl chloride D) 3-methylpentanoyl chloride E) none of these 9. What is the name of the following compound?

A. C.

2-chlorohexyl ethanoate B. 1-chlorohexyl ethanoate ethyl 2-chlorohexanoate D. ethyl 1-chlorohexanoate

10. Reaction of acetic acid, CH3CO2H, with isotopically labeled CH318OH and catalytic sulfuric acid gives:

Section II: Transformations. Supply the missing starting material, reagent(s) or missing product(s) for 8 of the following 11 transformations. Include stereochemistry if needed. If more than one product is formed circle the major product. (6 points each) The first 8 will be graded if there is no indication which 3 are to be omitted. i)

The most efficient way to make an amide is via an acid chloride O CO2H

NH2

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ii) O

Wolff kishner would do it but it would take out both..

H H O O

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ iii) O

Ph

You did one of these in lab!

Me

Ph

H

Me

Ph

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

iv)

Unfortunately does not stop at one addition...

O

1) PhMgBr

2) H 2O O ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ v) Can you make an ester directly from an amide? O O

NH 2 OMe ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ vi) O Sledge hammer of a reducer!! 1) xs LiAlH4 O 2)

H 2O

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ There are several approaches: vii) -make Carboxylic acid derivative then reduce gently O O -reduce thoroughly then oxidize gently

OH

H

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ viii) All organic students should remember this one!! O

OH

H

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ix) O

HNEt2

, three syllables - ENAMINE! One word,

cat. H+

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

x)

O

Baeyer-Villiger consider migratory aptitude mCPBA

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ xi) thioacetals protect carbonyls but also allows for the O carbonyl carbon to be used as a nucleophile. S

S

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Section III: Mechanism 1. Suggest a detailed mechanism for any two (2) of the following transformations. Be sure to include all arrows and resonance structures where necessary. Use the following pages to write your mechanisms (30 pts) (a)

CN

OH

H+/H2O O

(b)

O

N H+ cat

N H

Dean-Stark

(c) O O

O

H 3O+ +

(d)

O H+ OH

O

EtOH OEt

OH HO

Extra page for Mechanism I

a) acid catalyzed hydrolysis of nitriles - keep track of proton transfers and remember your rules for acid conditions mechanisms b) enamine formation. c) hydrolysis of acetal to reveal protected carbonyl d) Fischer esterification

Extra page for Mechanism II

Section IV: Synthesis: Suggest a reasonable synthesis for one of the following products from the given starting material. You should include all intermediate compounds/products formed in your synthetic scheme. (15 pts) Partial credit will be given for retrosynthetic analysis. (a)

O

O N

(b)

O

OH Ph

H

H

a) convert to a carboxylic acid derivative ester, react CAD to obtain appropriate amide. b) attack with appropriate nucleophiles...make sure carbon is electrophilic enough each time...