Question

Methylpent-1-ene how to prepare from alkynes via hydrogenation

Answer 1

(CH3)2C(CH2CH3)CCCH(CH3)2 2) HCCCH2CH2CH3 3) CH3CH=CHCH=CHCCCH3 4) BrCH2CH2CCCH2CH3
5) Draw acetylene 6) Draw (S)-5-phenyloct-2-yne 7) Draw hepta-3,6-dien-1-yne
8) The carbon-carbon triple bond of an alkyne is composed of
A) 3 s bonds B) 3 p bonds C) 2 s bonds and 1 p bond D) 1 s bond and 2 p bonds
9) Why are terminal alkynes more acidic than other hydrocarbons?
10) Provide the structure of the major organic product(s) in the reaction below.
CH3CH2C CH
1) NaNH2
2) PhCH2Br
11) Which of the species below is less basic than acetylide?
A) CH3Li
B) CH3ONa
C) CH3MgBr
D) both A and C
E) all of the above
12) Describe a chemical test for distinguishing terminal alkynes from internal ones.
13) 2-Methylhex-3-yne can be prepared by the reaction of an alkynide with an alkyl halide. Does the better
synthesis involve alkynide attack on bromoethane or on 2-bromopropane? Explain your reasoning.
14) Provide the structure of the major organic product(s) in the reaction below.
C C Na + Br
15) Provide the structure of the major organic product(s) in the reaction below.
C CH
NaNH2
O
H3O+
16) Provide the structure of the major organic product(s) in the reaction below.
H2
Lindlar's
catalyst
17) Provide the structure of the major organic product(s) in the reaction below.
CH3CH2 C C CH3
Na
NH3
18) Provide the structure of the major organic product(s) in the reaction below.
C CH
HBr (1 equivalent)
19) Provide the structure of the major organic product(s) in the reaction below.
C CH
HgSO4
H2SO4, H2O
20) Provide the structure of the major organic product(s) in the reaction sequence below.
C CH
Sia2BH H2O2
OH-
21) Provide the structure of the major organic product(s) in the reaction below.
1) O3
2) H2O
22) To a solution of propyne in diethyl ether, one molar equivalent of CH3Li was added and the resulting
mixture was stirred for 0.5 hour. After this time, an excess of D2O was added. Describe the major organic
product(s) of this reaction.
A) CH3CCD + CH4
B) CH3CCCH3
C) CD3CCD3
D) CH3CCCD3
E) CH3CCD + CH3D
23) Provide the structure of the major organic product(s) in the reaction below.
Ph Ph
D2
Pd / BaSO4 / quinoline
24) Which of the alkyne addition reactions below involve(s) an enol intermediate?
A) hydroboration/oxidation
B) treatment with HgSO4 in dilute H2SO4
C) hydrogenation
D) both A and B
E) none of the above
25) Draw the products which result when oct-3-yne is heated in basic potassium permanganate solution.
QUESTIONS 26-33 INVOLVE MULTISTEP SYNTHESES. PROVIDE THE STEPS BY WHICH THE
PRODUCT GIVEN CAN BE PREPARED FROM THE STARTING MATERIAL GIVEN.
26) Prepare racemic 2,3-dibromobutane from propyne 27) Prepare meso-2,3-dibromobutane from propyne
28) Prepare hept-1-yne from hept=1-ene. 29) Prepare butylbenzene from phenylacetylene
30) Prepare trans-pent-2-ene from propyne.
31) Prepare the compound shown below from acetylene.
OH
32) Prepare the compound shown below from acetylene.
O
H CH3
H3C H
33) How many distinct alkynes exist with a molecular formula of C4H6?
A) 0 B) 1 C) 2 D) 3 E) 4
34) Name the compound which results when pent-2-yne is subjected to catalytic hydrogenation using a
platinum catalyst.
35) Which of the following reagents should be used to convert hex-3-yne to (E)-hex-3-ene?
A) H2, Pt B) Na, NH3 C) H2, Lindlar's catalyst D) H2SO4, H2O E) HgSO4, H2O
36) Which of the following reagents should be used to convert hex-3-yne to (Z)-hex-3-ene?
A) H2, Pt B) Na, NH3 C) H2, Lindlar's catalyst D) H2SO4, H2O E) HgSO4, H2O
37) Draw the product that results when CH3CCLi reacts with CH3CH2COCH2CH3 followed by addition of H2O
38) Name the compound which results when pent-1-yne is treated with sodium in liquid ammonia.
39) Explain why the synthetic route shown below would be unsuccessful.
HC C Na
CH3CH2Br NaNH2
Br
40) Explain why the synthetic route shown below would be unsuccessful.
HC C Na
CH3CH2Br NaOCH3 CH3CH2Br
C C
41) Provide the major organic product of the reaction shown below.
C CH
NaNH2 Ph H
O
H3O+