Now that we’ve covered alkyl halides, sulfonyl chlorides can be used to convert alcohols into another great leaving group: sulfonate esters.
Learning the mechanism of Sulfonyl Chlorides.
This conversion proceeds without the use of SN2, meaning that we expect retention of configuration.
Yes we know, there is an extra methyl in the original molecule in the video. However, we decided to remove it completely from the problem.
This allows for a backside attack to successfully take place in the last step (seen by the blue Nu-).