triisopropylsilyyli

Triisopropylsilyll (TIPS) is an organosilicon protecting group commonly employed in organic synthesis to shield alcohols or other nucleophilic heteroatoms from undesired reactions. The group is derived from triisopropylsilyl chloride, a silicon-based compound in which a silicon atom bears three isopropyl (C3H7) groups and one halogen or leaving group. The bulk and hydrophobic character of the isopropyl substituents render TIPS groups highly sterically demanding, providing strong protection against acid- or base-catalyzed cleavage and oxidation.

The installation of a TIPS group typically proceeds by reacting a free alcohol with triisopropylsilyl chloride in the presence of a base such as imidazole or pyridine. The reaction leads to the formation of a TIPS ether, with the concomitant expulsion of the halide. Because the resulting ether is resistant to many common reagents, it is valuable in multistep syntheses where selective deprotection of other protecting groups is required. Removal of the TIPS group usually requires fluoride ions, such as tetra-n-butylammonium fluoride (TBAF), which selectively cleave the Si–O bond while sparing many other protecting groups.

TIPS-protected alcohols are particularly useful in carbohydrate chemistry, peptide synthesis, and the preparation of complex natural products. Their large size can also accelerate chromatography separations by increasing hydrophobicity. Safety considerations include the handling of silicon halides and fluoride reagents, both of which can be hazardous and require standard laboratory precautions.