Question

This is a Solvent-Free Synthesis of Chalcones: Claisen-Schmidt Condensation

The Chalcone starting materials are:

p-bromoscetophenone (solid)

p-chlorobenzaldehyde (solid)

11. [3 points) Draw the curved-arrow mechanism for your chalcone from the starting materials that you used. Explain why this reaction produces only one chalcone and not a mixture.

Answer 1

Solution: claisen-Schmidt condensation The condensat of an aomatie alde hyde (without - With te aliphede o an aromate aldehyde or ketone Chainy (urtorp Fy hjdregen) in pauserie of delatively strang base to tom d,punsaturated adehrde ketone OY cH3 c IH BY CI BT chalione Mechunism cH 3 c CH Naoh (cat) Step- 1 BY BY Br cCH2 CI stap.r 13Y BY OH slep 3 Br chalcone ctan s) step-1: Enolate formation of P-bromoacttophenone in basic tandition s tep 2: Readtion of enolate with p-cl benzuldehde to gie B-hyday ketone.

step-3: Dehjdruhon in basie Condition to give nseturated ketone Solid state This aeaction curried oud without an Solvent geact ion This is example of green chimisty CAS U we use unsubsti tuted starting raur matemal tor ch ulcone 1othesis, thin we will get mixtuse ot product f we can avoid B uce ot substituted Side reation such as starting materiu multiple condensat ion, pulymnizetion and Yearrangemends The reuction produc on1 one ch alcone and not mixtux because hex we ued substituted starting muteri This stasting materinl give tran- chalcone major becuu ge of stabili Cis-chlcone to truns chlconc mor steme hindrance as compund