Quiz 2 – Aldehydes and Ketones
1 Four C8H14O ketones are examined by 13Cnmr spectroscopy.
One of them has five distinct carbon signals. Which of the following fits this fact?
A) 4,4-dimethylcyclohexanone
B) 3,3-dimethylcyclohexanone
C) 2,2-dimethylcyclohexanone
D) 2,2,4,4-tetramethylcyclobutanone
2 Which of the following compounds could not be converted to pentanal in one or two steps?
A) 1-pentyne
B) trans-5-decene
C) 2-pentanone
D) 1-pentanol
3 Treatment of cyclohexanone with an excess of H218O produces 18O labeled cyclohexanone.
Which of the following is a likely intermediate in this isotope exchange? (the isotope is not named)
A) 1-cyclohexen-1-ol
B) 1,1-cyclohexanediol
C) 2-cyclohexen-1-one
D) 1,2-cyclohexanediol
4 Reaction of C6H5CHBr2 with NaOH in aqueous THF is likely to produce which product?
A) C6H5CHBrOH
B) C6H5CH(OH)2
C) C6H5CHO
D) C6H5CO2H
5 Which of the following carbonyl compounds reacts most rapidly with nucleophilic reagents?
A) benzaldehyde
B) 3,3-dimethylbutanal
C) acetophenone
D) 2,2-dimethylcyclohexanone
6 Which of the following amines would be best chosen for preparing an enamine derivative from
cyclohexanone?
A) dimethylamine
B) ethylamine
C) trimethylamine
D) hydroxylamine
7 Which reaction or sequence of reactions would best accomplish the following synthesis?
A) CH3NH2, acid catalyst & heat
B) CH2=NH, acid catalyst & heat
C) (i) NH3 acid catalyst & heat; (ii) CH2I2 & Zn(Cu)
D) (i) HCN & NaCN; (ii) LiAlH4 in ether
8 Heating cyclopentanone with either: I ethyl amine, or II diethylamine, together with an acid catalyst
leads to different results.
Which of the following best describes this difference?
A) I gives an imine & II fails to react
B) I gives an enamine & II fails to react
C) I gives an imine & II gives an enamine
D) I gives an enamine & II gives an imine
9 Which reaction or sequence of reactions would be best used to convert cyclohexanone to cis-1,2cyclohexanediol?
A) PCC in CH2Cl2 and base
B) (i) NaBH4; (ii) H3PO4 & heat; (iii) OsO4 in pyridine
C) (i) NaBH4; (ii) H3PO4 & heat; (iii) C6H5CO3H
D) (i) NaBH4; (ii) OsO4 in pyridine
10 A C9H10O compound has a strong absorption at 1686 -1cm in the infrared.
Which of the following compounds would be expected to display such an absorption band?
11 A C9H10O compound has a strong absorption at 1730 and two smaller but sharp absorption peaks at
2719 & 2818 -1cm in the infrared. The 1Hnmr has a strong doublet at δ1.0 ppm.
Which of the following compounds would be expected to display these features?
12 The Wittig reaction takes place between a carbonyl compound and a phosphorus ylid.
Which of the following represents the dipolar contributor to such an ylide?
A) I & II
B) II only
C) III only
D) I & IV
13 Which of the following reaction sequences would be best for converting cyclohexanol to
methylenecyclohexane, (CH2)5C=CH2 ?
A) (i) H3PO4 & heat; (ii) CH2I2 + Zn(Cu)
B) (i) PCC in CH2Cl2; (ii) CH3MgBr; (iii) H3PO4 & heat
C) PCC in CH2Cl2; (ii) (C6H5)3P=CH2
D) CH2N2 & heat
14 Which of the following Wittig reagents would be useful for converting R2C=O into R2CHCH=O?
A) (C6H5)3P=CH-OCH3
B) (C6H5)3P=CH-CH3
C) (C6H5)3P=Cl2
D) (C6H5)3P=CH-CH=CH2
15 Two equivalents of the Wittig reagent (CH3)2C=CH-CH=P(C6H5)3 were allowed to react with a C4H4O2
compound.
The chief product was 2,11-dimethyl-2,4,6,8,10-dodecapentaene, (CH3)2C=CH(CH=CH)3CH=C(CH3)2.
What was the C4H4O2 compound used in this reaction?
A) 2-butyne-1,4-diol
B) 1,2-cyclobutanedione
C) 1,3-butadien-2,3-diol
D) 2-butenedial