Final answer:
The stereochemical outcome for a hydrohalogenation reaction can be explained by the mechanism of nucleophilic attack, resulting in inversion of stereochemistry through an unstable transition state.
Step-by-step explanation:
The stereochemical outcome for a hydrohalogenation reaction can be explained by the mechanism of nucleophilic attack. In this reaction, a nucleophile (N) attacks a carbon atom while a more electronegative group (X) leaves, resulting in inversion of stereochemistry through an unstable transition state.
For example, when a primary alkyl halide undergoes hydrohalogenation, a neutral protic nucleophile can deprotonate after the substitution. This concerted mechanism, typical of primary alkyl halides, results in the formation of a product with inverted stereochemistry.
One common example is the O-methylation reaction using methyl iodide. In this reaction, an oxygen atom (from an alcohol) acts as a nucleophile, substituting the iodide which is a good leaving group.