The silyl-based protecting groups such as TBS and triisopropylsilyloxymethyl (Tom) are widely used in organic synthesis, mainly for the protection of hydroxyl groups. They are stable under many reaction conditions including certain acidic and basic conditions, and can be removed with fluoride, which is compatible with almost all functionalities commonly found in organic compounds including electrophilic groups such as arylamides and esters. For RNA synthesis, because TBS and Tom are the standard groups for the protection of 2′-OH of nucleosides, if the exo-amino groups of nucleobases could also be protected with silyl-based groups, the resulting RNA synthesis method would not only be suitable for the synthesis of a wide range of sensitive RNAs but also simplify RNA deprotection, that is, removing both 2′-OH and exo-amino protecting groups with fluoride simultaneously. Unfortunately, silyl-based protecting groups are not suitable for the protection of amines due to the low stability of the N-Si bond in the presence of even very mild acids such as water.