Questions and answers, Solved Problems on Functional Group Synthesis - Organic Chemistry
PROBLEMS
7.1. Show how you
would prepare each of the following products from the given starting material.
For each overall transformation
indicate (1) the starting and ending functional group and (2) what change in
oxidation level (if any) must be accomplished. Where more than one step is
required, show each step distinctly, including reagents and conditions needed
to effect the conversion
Answer:
(a) 1◦ Alcohol → aldehyde, [O] = +2, PCC or Swern oxidation
(b) Ester →
ether, [H] = −4
i. LAH
ii. NaH, CH3l
(c) Acid →
amide, no change
i. SOCl2, DMF
ii. CH3NHCH2CH3
or
i. DCC, Et3N, CH3NHCH2CH3
(d) Ketone →
methylene compound, +2
→ 0 [H]
i. Ph3P=CH2 (Wittig) or Me3SiCH2-Li
(Peterson)
(e) 1◦
Alcohol → aldehyde, −1 → +1, PCC or Swern oxidation
(f) Lactone →
lactol (hemiacetal); +3
→ +1; DIBAH, toluene, −78◦
(g) 2◦
Alcohol → 2◦ amine, no change
i. H2CrO4, acetone
ii. CH3NH3, NaBH3CN, H+
(h) Acid →
ester, +3 → +3
i. DCC, Et3N, EtOH
or
i.
oxallyl chloride
ii. EtOH, py
(i) Alkene →
alcohol; 0, −2 → +1, −3 no change
i. HgOAc2, H2O
ii. NaBH4
(j) Alkene →
alcohol; −1, −2 → −2, −1 no change
i. BH3−THF
ii. NaOH, H2O2
(k) Ketone →
alcohol + cyclization, +2 → 0 [O]
i. NaBH4
ii. TsOH, benzene,
(l) Ketone →
acetal; no change; HOCH2CH2CH2OH, TsOH,
toluene,
(m) Acid →
alcohol → acetylation, +3 → −1 [H]
i. BH3-THF
ii. Ac2O, py, DMAP
(n) Alkene →
alcohol, no change
i. HgOAc2, H2O
ii. NaBH4, MeOH
(o) Ketone →
α, β -unsaturated ketone; −2, −3, → −1, −2, [O]
i. LDA
ii. PhSeSePh
iii. H2O2
or
i. py−H+ Br−3
ii. K2CO3
(p) 2◦
Alcohol → acetal, 0 → +2, [O]
i. H2CrO4
ii. CH3OH, H+, Δ
(q) trans-Alkene → alkyne; −1, −1 → 0, 0 [O]
i. Br2, CCl4
ii.
NaNH2
(r)
(s) Acid →
amide, no change
i. DCC, Et3N, NH2R
or
i. oxallyl chloride,
ii. NH2R
(t) Alcohol →
ester, no change
i. ClCH2CH2C(O)Cl, py
(u) Alkene →
alcohol, no change
i. BH3 –THF
ii. NaOH, H2O2
(v) Alkyl bromide → alkene, [H]
i. NaC2H
ii. BuLi
iii. PrBr
iv. H2, P-2 Ni
7.2. Show two different starting materials from
which you could obtain each of the following compounds. Show the reagents and
conditions necessary to convert each of the starting materials into the desired
product.
Answer:
7.3. Give the final
products of the following reaction sequences and show the intermediate products
as well. If mixtures are expected, indicate which will be the major product.
Answer:
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