Issue Date: July 25, 2011
A More Stable Silyl Ether
Making more robust silyl ethers just got easier, thanks to a protecting group developed by Harvard University’s E. J. Corey, Huan Liang, and Lin Hu (Org. Lett., DOI: 10.1021/ol201640y). Because of its steric bulk, the new di-tert-butylisobutylsilyl protecting group, known as BIBS, can cling to alcohols in instances where other silyl protecting groups prove too labile. It’s particularly useful for protecting acidic hydroxyl moieties, such as those in phenols and carboxylic acids. Protected intermediates can be readily deprotected with tetrabutylammonium fluoride, the chemists report. BIBS triflate can also be used to protect primary amines directly, providing a new amino protecting group. Typically, N–Si bonds are prone to hydrolysis, but the bulky BIBS group resists such reaction and can be removed from the nitrogen by using hydrofluoric acid. The Harvard chemists report how to prepare BIBS triflate in two steps from inexpensive starting materials. But for those who like to simply crack open a bottle of protecting reagent, the researchers have teamed up with Gelest to make the material commercially available.
- Chemical & Engineering News
- ISSN 0009-2347
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