Used as a protecting group reagent in organic synthesis, particularly for alcohols and phenols. It introduces the 2-(trimethylsilyl)ethoxymethyl (SEM) group, which is stable under a variety of reaction conditions and can be selectively removed using mild acid or fluoride ions. This makes it valuable in multi-step syntheses, especially in the preparation of complex molecules like natural products and pharmaceuticals where selective protection and deprotection are required. Commonly employed in peptide and nucleotide chemistry due to its compatibility with sensitive functional groups.