One of the best protecting group strategies to selectively protect an alcohol in the presence of an amino group in an organic molecule is to use a silyl ether protecting group, such as tert-butyldimethylsilyl TBS or triisopropylsilyl TIPS group. These protecting groups can be selectively introduced to the alcohol moiety without affecting the amino group due to the difference in reactivity between the two functional groups.A specific example would be the selective protection of an alcohol in the presence of an amino group using tert-butyldimethylsilyl chloride TBSCl and imidazole as a base.Here is the mechanism of the protecting group reaction:1. The imidazole base deprotonates the alcohol, generating an alkoxide ion.2. The alkoxide ion attacks the silicon atom of the TBSCl, displacing the chloride ion.3. The tert-butyldimethylsilyl TBS group is now attached to the oxygen atom of the alcohol, forming a silyl ether and protecting the alcohol moiety.The amino group remains unaffected during this reaction due to its lower nucleophilicity compared to the alkoxide ion. The TBS group can be later removed using mild acidic conditions e.g., TBAF or HF to regenerate the free alcohol.In summary, the use of silyl ether protecting groups, such as TBS or TIPS, is an effective strategy for selectively protecting an alcohol in the presence of an amino group in an organic molecule.