Just like boc protects amines, TBDMS protects alcohols.
TBDMS chloride will protect alcohols. The silicon-oxygen bond is pretty strong, and the silicon-fluorine bond is even better. This provides a protecting group that's pretty robust - fluoride reagents are typically used for removing the silyl ether. More on that shortly...
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The fluoride ion is important to synthetic chemistry, often because it can be used to cleave silyl ethers (the silicon analogue of a carbon ether). Fluoride is notorious for holding onto water (like any tiny ion - lithium is about as bad), so even an "anhydrous" solution of TBAF in (say) THF will…
There are a number of "strong" acids that are essentially completely dissociated in water - hydrochloric and sulfuric acid are two of the most common. Unfortunately, these are often volatile (as in HCl), insoluble, or otherwise ill-behaved in organic solvents. The organic sulfonic acids are quite…
One of my best friends in undergrad, upon learning about the use of acetal protecting groups for carbonyls, exclaimed, "they're like ketone condoms!" Indeed. Protecting groups are ubiquitous in organic synthesis, and another one you see all the time is Boc, which is used to protect amines:
Boc2O,…
The series of Breaking Bad chemicals continues (spoilers inside). Previously: phosphine, mercury fulminate. Today: hydrogen fluoride.
HF is just that, H-F, or a hydrogen bound to a fluorine. All the other acids in this group - HCl, HBr, HI - are gases. What we call "hydrochloric acid" is HCl in…
how to deprotect O-TBDMS????
It can also protect acetylenes, or at least make them more soluble and amenable to a little crystal engineering magic. Although...the awkward shape can also be sort of a hindrance there...you get a bit of disorder. :(
The magic fluoride reagent is [tetra-n-butyl] ammonium hydrogen bifluoride, (HF2)-. Whether you are dissolving stone or cleaving Si-O, it goes where mere F- lacks cooperation. Aqueous surface tensions can be high (dissolving stone). A drop of Dawn dishwashing liquid or a Fluorad surfactant helps.
Oh my god! I just did a TBDMS protection of a primary alcohol using this very reagent (like 4 minutes ago). So weird...
Also, it isn't that stable. Some 90% TFA or formic acid, or even 1% HCl in dry methanol will pop it right off. Convenient when you want to remove it with another acid-labile group, a pain in the butt for orthogonality!
Xuse me, but some of your post are too condensed for a non chemist to be of interest. Perhaps the compounds are really too arcane for use outside the lab...