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 α-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.
In this experiment, (2,SE)-2,5-bis(lE)-3-phenylallylidene)cyclopentan-1-one example of a crossed aldol condensation. (BPC) is synthesized in an Initially, ë°ë¬ë°3-phenylalylidene)cyclopentan-1-one (PC) is formed dil. NaOH(aq) cinnamaldehyde cyclopentanone However, in the presence of excess cinnamaldehyde, PC rapidly undergoes a second condensation to form BPC: dil. NaOH(aq) cinnamaldehyde PC BPC OH OH- cinnamaldehyde H. H cinnamaldehyde OH Oh The first step involves the acid-base reaction between a strong base such as hydroxide ion and a hydrogen located a carbon alpha to a carbonyl group. In the subsequent step (see Step 2), the enolate attacks the carbonyl group of aldehyde and followed by the loss of OH- as a leaving group to give an enal, which has the alkene and the ketone functional groups
