answer

watching

views

11 Nov 2019

Overall Reaction:

Provide a full mechanism for a potential side reaction. Show all nonzero formal charges and intermediates. Please use arrows to clearly show bonds forming or breaking between atoms.

In this experiment, (2E,5E)-2,5-bis((E)-3-phenylallylidenejcyclopentan-1-one (BP is synthesized in an example of a crossed aldol condensation. Initially, (E)-2-((E)-3-phenylallylidene)cyclopentan-1-one (PC) is formed: dil. NaOH(aq) cinnamaldehyde cyclopentanone PC However, in the presence of excess cinnamaldehyde, PC rapidly undergoes a second condensation to form BPC: 0 dil. NaOH(aq) cinnamaldehyde PC BPC

answer

watching

319

views

For unlimited access to Homework Help, a Homework+ subscription is required.

You have 0 free answers left.
Get unlimited access to 3.8 million step-by-step answers.

Get unlimited access

Already have an account? Log in

Jean KeelingLv2

18 Jul 2019

Unlock all answers

Get 1 free homework help answer.

Already have an account? Log in

Join us on Discord

Chemistry Study Group

Join now

Related questions

Detailed Reaction Procedure:

Step 1: Cinnamaldehyde + Cyclopentanone (Mix for 1 min).

Step 2: Add 10% NaOH + Water to the mixture above (Mix for 3 min).

Step 3: Add Ethanol to the mixture above (Mix for 3 min). Precipitate will form.

Step 4: Collect precipitate by suction filtration and wash it with Glacial Acetic Acid + Water (Continue suction for 5 to 10 min).

Step 5: Transfer the crude product known as BPC (or (2E,5E)-2,5-bis((E)-3-phenylallylidene)cyclopentan-1-one)) into beaker with Ethanol and heat it up until it boils (or also known as "recrystallization").

Step 6: Collect the pure BPC (crystals) by suction filtration and wash it with Ice-Cold Ethanol (Continue suction for 5 min).

Overall Reaction:

a) Provide a full mechanism for the synthesis of BPC and a full mechanism for a potential side reaction. Include all nonzero formal charges and intermediates. Please use arrows to clearly show bonds forming or breaking between atoms. *The mechanism is already shown above, however. I would just like to know if it's correct, and please still show what the side reaction would be.*

b) Please explain the difference between a "self" aldol condensation and a "mixed" aldol condensation.

c) In order to have a successful mixed aldol condensation, describe two requirements of the reaction conditions that should be met?

d) Please explain why the Î±-hydrogen atoms of aldehydes and ketones are weakly acidic (enolizable). Also show the general reaction mechanism of the deprotonation of an aldehyde or ketone using NaOH.

Detailed Reaction Procedure:

Step 1: Cinnamaldehyde + Cyclopentanone (Mix for 1 min).

Step 2: Add 10% NaOH + Water to the mixture above (Mix for 3 min).

Step 3: Add Ethanol to the mixture above (Mix for 3 min). Precipitate will form.

Step 4: Collect precipitate by suction filtration and wash it with Glacial Acetic Acid + Water (Continue suction for 5 to 10 min).

Step 6: Collect the pure BPC (crystals) by suction filtration and wash it with Ice-Cold Ethanol (Continue suction for 5 min).

Overall Reaction:

a) There are 9 geometric isomers (i.e. âcisâ and âtransâ or âEâ and âZâ isomers) of BPC; however in this reaction, the product mixture is composed of one major geometric isomer of BPC. Clearly draw the major geometric isomer of BPC; then draw any two of the other 8 geometric isomers. Briefly describe why the formation of one geometric isomer predominates over the formation of the other 8 geometric isomers.

b) Ketones with Î±-hydrogens can undergo a process called, "keto-enol tautomerism". Please answer the following sub-parts regarding this process.

I) Draw the keto-enol tautomers of cyclopentanone.

II) Which of the two tautomers is more stable? Why is it more stable?

III) Please show the mechanism for the formation of keto-enol tautomers of cyclopentanone in the presence of an acid.

c) The last step of the formation of BPC involves dehydration of the aldol by elimination of a hydroxide ion; which is generally considered a poor leaving group. Please justify why the elimination of OH^â occurs in this reaction.

Weekly leaderboard

Home

Homework Help 3,900,000

Chemistry 830,000

Unlock all answers

Related textbook solutions

Basic Chemistry

Principles of Chemistry Molecular Approach

Principles of Chemistry Molecular Approach

Chemistry: Structure and Properties

Chemistry: A Molecular Approach

Chemistry: A Molecular Approach

Principles of Chemistry: A Molecular Approach

Chemistry: The Central Science

Related questions

Weekly leaderboard