What is the product when (2R,3R)-2-bromo-3-methylpentane is reacted with NaOH?

Question

Quizplus · Accepted Answer

11ecba2d_12b9_222c_a3bf_99f0aa538f09_MD0008_00 An S_N2 reaction is a substitution reaction in which a nucleophile attacks an electrophile and displaces a leaving group in one step. If the electrophile is a chiral center, its stereochemistry will be inverted by the reaction. Each chiral center is designated as R or S based on the spatial arrangement of its substituents. Each substituent is prioritized by molecular weight, and the lowest priority group is positioned to point into the plane (dash). If the groups are arranged in a clockwise order, the chiral center has an R configuration, whereas counterclockwise corresponds to an S configuration. Conversely, if the lowest priority group is pointing out of the plane (wedge), then a clockwise arrangement corresponds to S and counterclockwise is R. In an S_N2 reaction, an electrophile that has an Rconfiguration before substitution will adopt an Sconfiguration after the reaction and vice versa, if the nucleophile has the same priority ranking as the leaving group. In this S_N2 reaction, ⁻OH (nucleophile) attacks carbon 2 in (2R,3R)-2-bromo-3-methylpentane, while bromide (leaving group) leaves. Because the electrophile (carbon 2) is chiral, its configuration is inverted from R to S. Carbon 3 is also chiral but retains the R configuration because it does not participate in the reaction. Choice B correctly shows carbon 2 in the S configuration and carbon 3 in the R configuration. (Choices A, C, and D) The configuration of carbon 2 should be S (wedge in this case) because it is the electrophile, so its configuration inverts in the S_N2 reaction. The configuration of carbon 3 should remain R (dash in this case) because it does not participate in the S_N2 reaction. Educational objective: An S_N2 reaction is a concerted substitution reaction where a nucleophile forms a bond with an electrophile while a leaving group is displaced. If the electrophile is a chiral center, its stereochemistry will be inverted in the product. Therefore, if the electrophilic carbon has an R configuration, it will adopt an S configuration after the reaction and vice versa, provided the priority ranking of the nucleophile is the same as the leaving group.

What Is the Product When (2R,3R)-2-Bromo-3-Methylpentane Is Reacted with NaOH