Brosyl group
As Brosylgruppe is covalently bound radical of the p -Brombenzolsulfonsäure (Br-C 6 H 4 -SO 2 -) designates the most through an oxygen atom or a NR group in organic compounds is bound. They are therefore esters or amides of p -bromobenzenesulfonic acid. The esters are usually referred to as brosylates and should not be confused with the salts of the same name of p -bromobenzenesulfonic acid ( brosylates ). The amides are p -bromobenzenesulfonic acid amides. The tosyl group and the nosyl group are structurally related to the brosyl group.
properties
The brosyl group is electron-withdrawing, which is why the underlying p -bromobenzenesulfonic acid is a strong acid and the brosylate group is a good leaving group . This can easily be cleaved from the molecule with substitution by suitable nucleophiles . For this reason, brosyl compounds are very reactive and have a limited lifespan. This can be increased by storage in the absence of nucleophiles, for example water or alcohols.
use
Because of their property as a leaving group, brosylates are used in preparative organic chemistry . By converting alcohols into brosylates, the poor leaving group HO - is converted into a good leaving group, which enables substitution reactions at this position. The anion of p -bromobenzenesulfonic acid emerges as a leaving group . However, the esters of p -bromobenzenesulfonic acid (brosylates) are less reactive than the corresponding triflates .
Individual evidence
- ^ Siegfried Hauptmann : Organic Chemistry , 2nd edition, VEB Deutscher Verlag für Grundstoffindustrie, Leipzig, 1985, p. 482, ISBN 3-342-00280-8 .
- ↑ Entry on methylbenzenesulfonic acids. In: Römpp Online . Georg Thieme Verlag, accessed on September 29, 2014.
- ^ Author collective, Organikum , 21st edition, p. 217, Wiley-VCH, Weinheim, 2001, ISBN 3-527-29985-8 .