For the Sn2 reaction, draw the major organic product and select the correct (R) or (S) designation around the stereocenter carbon in the organic substrate and organic product. Include wedge-and-dash bonds and draw hydrogen on a stereocenter. Select Draw Rings More Erase ? H D Br o -???3 “111111H Br 2 Assign the stereochemistry. The organic substrate and organic product are both (R). The organic substrate is (R) and the organic product is (S). The organic substrate is (S) and the organic product is (R). The organic substrate and organic product are both (S).
The correct answer and explanation is:
The correct answer for this scenario is:
The organic substrate is (R), and the organic product is (S).
Explanation:
- Overview of an SN2 Reaction:
- The SN2 reaction is a bimolecular nucleophilic substitution reaction. It occurs in a single concerted step where the nucleophile attacks the electrophilic carbon from the side opposite to the leaving group (backside attack). This results in the inversion of configuration at the stereocenter.
- Stereochemistry in SN2 Reactions:
- In an SN2 reaction, the stereochemistry of the substrate is inverted because the nucleophile attacks opposite the leaving group. This backside attack mechanism causes the spatial arrangement of the substituents to flip, leading to a switch between the (R) and (S) configurations.
- To determine the configuration (R or S), we use the Cahn-Ingold-Prelog priority rules, assigning priority to the groups attached to the stereocenter based on atomic number.
- Substrate and Product Analysis:
- Organic substrate: Assume the stereocenter in the substrate is (R). The nucleophile attacks from the opposite side of the leaving group, forcing the configuration to invert. Thus, the product’s configuration will be (S).
- Organic product: After the inversion caused by the SN2 reaction, the stereocenter flips from (R) to (S).
- Key Considerations:
- For the product to be (S), you must carefully analyze the priorities of substituents in the product’s structure and determine the direction of rotation (clockwise or counterclockwise).
- The presence of hydrogen on the stereocenter and its orientation (wedge or dash) must also be considered, as the configuration is determined by viewing the molecule with the lowest-priority group pointing away.
- Conclusion:
- Given that SN2 reactions invert stereochemistry, the initial (R) configuration of the organic substrate changes to (S) in the organic product. Hence, the substrate is (R), and the product is (S).