Identify the major product [B] in the following reaction sequence:

Step-by-step solution

The given reaction sequence involves two main steps: 1. Substitution Reaction ( S_N2 ): The first step is the reaction of the chiral alkyl bromide with NaN₃ in DMF. DMF (Dimethylformamide) is a polar aprotic solvent, which strongly favors the S_N2 mechanism. In an S_N2 reaction, the nucleophile ( N₃^- ) attacks the electrophilic carbon from the side opposite to the leaving group ( Br^- ), resulting in an inversion of configuration at that specific chiral center (C2). In the given Fischer projection, the -Br group i