Textbook Question
Show how each of the following compounds can be prepared, using the given starting material:
e.
13. Alcohols and Carbonyl Compounds
Organometallic Cumulative Practice
6:20 minutesProblem 29c
Textbook Question
Show how you would accomplish the following syntheses. You may use whatever additional reagents you need.
(c) 
Verified step by step guidance1
Step 1: Analyze the starting material and the product. The starting material is a bromomethyl ketone, and the product is an α,β-unsaturated ketone with a phenyl group attached to the β-carbon. This suggests that the reaction involves a substitution followed by elimination.
Step 2: Perform a nucleophilic substitution reaction. Use a phenyl nucleophile, such as a phenyl Grignard reagent (PhMgBr) or phenyl lithium (PhLi), to replace the bromine atom with a phenyl group. This step generates an intermediate with a phenyl group attached to the α-carbon.
Step 3: Introduce conditions for elimination. Use a base, such as potassium tert-butoxide (KOtBu) or sodium hydride (NaH), to promote the elimination of a proton from the α-carbon and the formation of a double bond between the α- and β-carbons. This step results in the formation of the α,β-unsaturated ketone.
Step 4: Ensure stereochemistry and regioselectivity. Verify that the elimination occurs in the correct position to yield the desired conjugated system with the phenyl group attached to the β-carbon.
Step 5: Purify the product. Use techniques such as distillation or chromatography to isolate the α,β-unsaturated ketone with the phenyl group attached to the β-carbon.
Verified video answer for a similar problem:This video solution was recommended by our tutors as helpful for the problem above
Video duration:
6mKey Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Nucleophilic Substitution
Nucleophilic substitution is a fundamental reaction in organic chemistry where a nucleophile attacks an electrophilic carbon atom, replacing a leaving group. In this synthesis, the bromine atom in CH2Br acts as a leaving group, allowing the nucleophile to form a new bond with the carbon atom. Understanding this mechanism is crucial for predicting the outcome of the reaction.
Recommended video:
Guided course
01:47
Nucleophiles and Electrophiles can react in Substitution Reactions.
Aldol Condensation
Aldol condensation is a reaction between aldehydes or ketones that contain alpha-hydrogens, leading to the formation of β-hydroxy aldehydes or ketones, which can further dehydrate to form α,β-unsaturated carbonyl compounds. This process is essential in the synthesis shown, as it allows for the formation of the desired product through the coupling of two carbonyl compounds.
Recommended video:
Guided course
09:51Crossed Aldol
Electrophilic Aromatic Substitution
Electrophilic aromatic substitution is a reaction where an electrophile replaces a hydrogen atom on an aromatic ring. In the context of the provided synthesis, the phenyl group (Ph) can be introduced to the aromatic compound through this mechanism, allowing for the formation of the final product. Recognizing the role of aromaticity and the stability of the intermediates is key to understanding this step.
Recommended video:
Guided course
03:07EAS Review
Related Videos
Related Practice