Search results
Results From The WOW.Com Content Network
The classical protecting groups for alcohols are esters, deprotected by nucleophiles; triorganosilyl ethers, deprotected by acids and fluoride ions; and (hemi)acetals, deprotected by weak acids. In rarer cases, a carbon ether might be used.
tert-Butyloxycarbonyl protecting group. The tert-butyloxycarbonyl protecting group or tert-butoxycarbonyl protecting group [1] (BOC group) is an acid-labile protecting group used in organic synthesis. The BOC group can be added to amines under aqueous conditions using di-tert-butyl dicarbonate in the presence of a base such as sodium hydroxide:
This is useful because alcohols are poor leaving groups in S N 2 reactions, in contrast to the tosylate group. It is the transformation of alkyl alcohols to alkyl tosylates that allows an S N 2 reaction to occur in the presence of a good nucleophile. A tosyl group can function as a protecting group in organic synthesis. Alcohols can be ...
Silyl ethers are a group of chemical compounds which contain a silicon atom covalently bonded to an alkoxy group. The general structure is R 1 R 2 R 3 Si−O−R 4 where R 4 is an alkyl group or an aryl group. Silyl ethers are usually used as protecting groups for alcohols in organic synthesis.
The ease of installation of the protecting group follows the order: 1 o > 2 o > 3 o, allowing the least hindered hydroxyl group to be protected in the presence of more hindered hydroxyls. [ 4 ] Protection of equatorial hydroxyl groups can be achieved over axial hydroxyl groups by the use of a cationic silyl species generated by tert ...
Benzyl is commonly used in organic synthesis as a robust protecting group for alcohols and carboxylic acids. Treatment of alcohol with a strong base such as powdered potassium hydroxide or sodium hydride and benzyl halide (BnCl or BnBr) [9] [10]
The protection mechanism begins with the base deprotonating the alcohol group. Next, the deprotonated alcohol group attacks the silyl atom of the silyl halide compound. The halide acts as a leaving group and ends up in solution. A workup step follows to remove any excess base within the solution. The overall reaction scheme is as follows:
Thermolabile protecting groups; 2,2,2-Trichloroethoxycarbonyl chloride This page was last edited on 15 September 2015, at 12:37 (UTC). ...