Propose a mechanism for each reaction.
(c)

Verified step by step guidance

1. Step 1: Recognize the reaction type. This reaction involves dehydration of an alcohol (CH2OH group) under acidic conditions (H2SO4 and heat). The goal is to remove water and form alkenes as products.
2. Step 2: Protonation of the alcohol group. The sulfuric acid (H2SO4) donates a proton (H+) to the hydroxyl group (-OH) of the alcohol, converting it into a better leaving group (H2O). This step increases the reactivity of the molecule.
3. Step 3: Formation of a carbocation intermediate. The water molecule leaves, generating a carbocation at the carbon where the alcohol group was attached. This carbocation is the key intermediate in the reaction.
4. Step 4: Rearrangement and elimination. The carbocation can undergo rearrangement to form more stable carbocations if possible. Then, elimination occurs where a proton is removed from a neighboring carbon atom, leading to the formation of double bonds (alkenes).
5. Step 5: Formation of multiple products. Depending on the position of the double bond and the stability of the resulting alkenes, multiple products can form. In this case, the products are cyclopentene, methylenecyclopentane, and 1-methylcyclopentene.

Key Concepts

Reaction Mechanism

A reaction mechanism is a step-by-step description of how reactants transform into products in a chemical reaction. It outlines the sequence of elementary steps, including bond breaking and formation, and the intermediates formed during the process. Understanding the mechanism is crucial for predicting the outcome of reactions and for designing new synthetic pathways.

Types of Organic Reactions

Organic reactions can be classified into several types, including substitution, addition, elimination, and rearrangement reactions. Each type has distinct characteristics and mechanisms. Recognizing the type of reaction helps in predicting the behavior of reactants and the nature of the products formed, which is essential for proposing accurate mechanisms.

Curved Arrow Notation

Curved arrow notation is a visual representation used in organic chemistry to illustrate the movement of electrons during a reaction. Arrows indicate the direction of electron flow, showing how bonds are broken and formed. Mastery of this notation is vital for accurately depicting reaction mechanisms and understanding the underlying electronic changes that occur.