Draw a perspective structure or a Fischer projection for the products of the following S_N2 reactions.
(e)

Verified step by step guidance

1. Identify the type of reaction: This is an SN2 reaction, which involves a single-step mechanism where the nucleophile attacks the electrophilic carbon, displacing the leaving group in a backside attack. This results in inversion of configuration at the carbon center.
2. Analyze the reactants: The substrate is a secondary alkyl halide (2-bromobutane), and the nucleophile is methoxide ion (CH3O⁻) in methanol (CH3OH). Methoxide is a strong nucleophile, favoring the SN2 mechanism.
3. Determine the stereochemistry of the substrate: The carbon bonded to the bromine atom is a chiral center. In the given structure, the substituents are CH3, H, CH2CH2CH3, and Br. Assign the configuration (R or S) to this carbon using the Cahn-Ingold-Prelog priority rules.
4. Predict the product: In an SN2 reaction, the nucleophile (CH3O⁻) will attack the carbon from the side opposite to the leaving group (Br), leading to inversion of configuration. Draw the product with the methoxy group (OCH3) replacing the bromine atom and inverted stereochemistry at the chiral center.
5. Choose the representation: Draw the product as either a perspective structure (showing the 3D arrangement of groups) or a Fischer projection (a 2D representation where horizontal lines represent bonds coming out of the plane and vertical lines represent bonds going into the plane). Ensure the stereochemistry is correctly represented in the chosen format.

Key Concepts

S_N2 Mechanism

The S_N2 mechanism is a type of nucleophilic substitution reaction where a nucleophile attacks an electrophile, resulting in the simultaneous displacement of a leaving group. This reaction occurs in a single concerted step, leading to the inversion of configuration at the carbon center. It is favored by primary and some secondary substrates due to steric accessibility.

Fischer Projection

A Fischer projection is a two-dimensional representation of a three-dimensional organic molecule, particularly useful for depicting stereochemistry. In this format, vertical lines represent bonds that project away from the viewer, while horizontal lines represent bonds that project towards the viewer. Fischer projections are commonly used to illustrate the stereochemistry of carbohydrates and amino acids.

Nucleophiles and Electrophiles

Nucleophiles are species that donate an electron pair to form a chemical bond, while electrophiles are electron-deficient species that accept an electron pair. In S_N2 reactions, the nucleophile attacks the electrophile, leading to the substitution of the leaving group. Understanding the nature of these species is crucial for predicting the outcome of organic reactions.