What is the product of each of the following reactions?
b.

Verified step by step guidance

1. Step 1: Recognize the reaction type. This is a typical example of a cross-coupling reaction, specifically a Heck reaction. The Heck reaction involves the coupling of an aryl or vinyl halide (in this case, an aryl iodide) with an alkene in the presence of a palladium catalyst and a base.
2. Step 2: Identify the reactants. The aryl iodide is a substituted cyclopentene ring with an iodine atom attached. The alkene is a terminal alkene with a methyl group attached to the double bond.
3. Step 3: Understand the mechanism. In the Heck reaction, the palladium catalyst facilitates the oxidative addition of the aryl halide to form a palladium-aryl complex. The alkene then coordinates to the palladium center, followed by migratory insertion of the alkene into the palladium-aryl bond.
4. Step 4: Predict the regioselectivity. The alkene will couple with the aryl group at the less sterically hindered position, forming a new C-C bond. The product will be a substituted alkene where the aryl group is attached to the terminal carbon of the alkene.
5. Step 5: Consider stereochemistry. The Heck reaction typically proceeds with retention of the double bond geometry in the alkene. The final product will retain the E-configuration of the alkene unless otherwise specified.

Key Concepts

Organometallic Chemistry

Organometallic chemistry involves compounds containing metal-carbon bonds, where metals can be transition metals or main group elements. These compounds are crucial in various reactions, including cross-coupling reactions, where they facilitate the formation of carbon-carbon bonds. Understanding the role of organometallic reagents is essential for predicting the products of reactions involving these species.

Cross-Coupling Reactions

Cross-coupling reactions are a class of reactions in organic chemistry where two different organic groups are joined together using a metal catalyst. Common examples include the Suzuki and Heck reactions, which utilize palladium catalysts to couple aryl halides with alkenes or other nucleophiles. Recognizing the mechanism and conditions of these reactions is vital for determining the expected products.

Palladium Catalysis

Palladium catalysis is a key technique in organic synthesis, particularly in cross-coupling reactions. Palladium can exist in multiple oxidation states, allowing it to facilitate the transfer of groups between reactants. The choice of ligands and reaction conditions can significantly influence the efficiency and selectivity of the reaction, making it important to understand how these factors affect the outcome.