Show two ways you could synthesize each of the following secondary alcohol by adding an appropriate Grignard reagent to an aldehyde.
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Verified step by step guidance

1. Step 1: Identify the target molecule, which is a secondary alcohol. The secondary alcohol shown has a cyclohexyl group, a hydroxyl group (-OH), and a prop-2-enyl group attached to the same carbon atom.
2. Step 2: Recall the general mechanism for synthesizing secondary alcohols using Grignard reagents. A Grignard reagent (R-MgX) reacts with an aldehyde to form a secondary alcohol after protonation.
3. Step 3: First synthesis route: Use cyclohexylmagnesium bromide (C6H11-MgBr) as the Grignard reagent and prop-2-enal (CH2=CH-CHO) as the aldehyde. The Grignard reagent will attack the carbonyl carbon of the aldehyde, forming the secondary alcohol after protonation.
4. Step 4: Second synthesis route: Use prop-2-enylmagnesium bromide (CH2=CH-CH2-MgBr) as the Grignard reagent and cyclohexanecarboxaldehyde (C6H11-CHO) as the aldehyde. The Grignard reagent will attack the carbonyl carbon of the aldehyde, forming the secondary alcohol after protonation.
5. Step 5: In both cases, ensure the reaction is carried out in an anhydrous environment to prevent the Grignard reagent from reacting with water. After the reaction, protonate the intermediate with a mild acid (e.g., HCl or H2O) to yield the secondary alcohol.

Key Concepts

Grignard Reagents

Grignard reagents are organomagnesium compounds represented as R-MgX, where R is an organic group and X is a halogen. They are highly reactive and act as nucleophiles, allowing them to attack electrophilic carbon centers, such as those found in carbonyl compounds. This property makes them essential for forming new carbon-carbon bonds in organic synthesis.

Aldehyde Reactivity

Aldehydes are carbonyl compounds characterized by the presence of a carbonyl group (C=O) bonded to at least one hydrogen atom. They are more reactive than ketones due to the presence of the hydrogen, which makes the carbonyl carbon more electrophilic. This reactivity allows Grignard reagents to effectively add to aldehydes, leading to the formation of secondary alcohols upon hydrolysis.

Synthesis of Secondary Alcohols

Secondary alcohols can be synthesized by the nucleophilic addition of Grignard reagents to aldehydes. When a Grignard reagent reacts with an aldehyde, it forms a tetrahedral intermediate, which upon protonation yields a secondary alcohol. Understanding the mechanism of this reaction is crucial for designing synthetic pathways in organic chemistry.