RSS-Feed abonnieren
DOI: 10.1055/s-2006-950446
Tetra-n-Butylammonium Tribromide
Publikationsverlauf
Publikationsdatum:
22. September 2006 (online)
Biographical Sketches
Introduction
Tetra-n-butylammonium tribromide (TBATB) is one of the most widely used organic ammonium tribromides (OATB’s) for bromination [1-3] of several organic substrates.
Because it is a stable crystalline solid, easy to handle and maintains the desired reaction stoichiometry it is looked at as a substitute of Br2. It can also be considered as a ‘greener’ brominating agent [4] as well as an in situ generator of anhydrous HBr.
Other types of reactions like acylation, oxidation and protection/deprotection of several functional groups can be performed with TBATB in catalytic amounts and under solvent-free conditions.
Preparation
Properties
Yellow-orange crystalline ionic solid, mp 75 °C (acetonitrile). IR bands at 170 and 190 cm-1. Monoclinic space group C2/c structure determined by X-ray.
Abstracts
(A) Preparation of a wide variety of flavones and aurones starting from 2′-acetoxychalcones 1 in high yields (36-55% and 65-85%, respectively) was accomplished in two steps, being the first selective bromination with TBATB (70-80% for 2 and 75-85% for 3). [5] |
|
(B) Direct condensation of various alcohols and carboxylic acids was efficiently achieved with a catalytic amount of TBATB under solvent-free conditions at reflux. Chemoselectivity for primary alcohols was observed when secondary and phenolic alcohols were also present. [6] |
|
(C) Selective protection of various carbonyl compounds to the corresponding 1,3-oxathiolanes was performed with catalytic amount of TBATB. Chemoselective deprotection of synthesized 1,3-oxathiolanes to the parent carbonyl compounds was also obtained with TBATB. No bromination on α-keto position, aromatic ring, allylic position or double bond was observed. [7] |
|
(D) Gosain and Sharma described the kinetics and mechanism for oxidation of vicinal and non-vicinal diols to the corresponding aldehydes and hydroxycarbonyl compounds, respectively. Excellent yields were obtained. [8] |
|
(E) Solvent-free, chemoselective diacylation of aldehydes was accomplished using a catalytic amount of TBATB, without side reaction yielding brominated products. Chemoselective cleavage of diacylates was also reported with TBATB when the reaction was performed in different conditions. [9] |
|
(F) TBATB promotes tetrahydropyranylation and detetrahydropyranylation of primary, secondary and tertiary alcohols when present in 10 mol%. Mild reaction conditions make both reactions compatible with other acid-sensitive groups such as OTs, nitro and Boc, among others. [10] |
|
- 1
Mondal E.Bose G.Khan AT. Synlett 2001, 785 - 2
Bose G.Li Y.Bhujarbarua PM.Kalita D.Khan AT. Chem. Lett. 2001, 30: 290 - 3
Bose U.Chaudhuri MK.Dey D.Dhar SS. Pure Appl. Chem. 2001, 73: 93 - 4
Bora U.Chaudhuri MK.Dehury SK. Curr. Sci. 2002, 82: 1427 - 5
Bose G.Mondal E.Khan AT.Bordoloi MJ. Tetrahedron Lett. 2001, 42: 8907 - 6
Naik S.Kavala V.Gopinath R.Patel BK. ARKIVOC 2006, (i): 119 - 7
Mondal E.Sahu PR.Bose G.Khan AT. Tetrahedron Lett. 2002, 43: 2843 - 8
Gosain J.Sharma PK. Indian Acad. Sci. (Chem. Sci.) 2003, 115: 135 - 9
Kavala V.Patel BK. Eur. J. Org. Chem. 2005, 441 - 10
Naik S.Gopinath R.Patel BK. Tetrahedron Lett. 2001, 42: 7679
References
- 1
Mondal E.Bose G.Khan AT. Synlett 2001, 785 - 2
Bose G.Li Y.Bhujarbarua PM.Kalita D.Khan AT. Chem. Lett. 2001, 30: 290 - 3
Bose U.Chaudhuri MK.Dey D.Dhar SS. Pure Appl. Chem. 2001, 73: 93 - 4
Bora U.Chaudhuri MK.Dehury SK. Curr. Sci. 2002, 82: 1427 - 5
Bose G.Mondal E.Khan AT.Bordoloi MJ. Tetrahedron Lett. 2001, 42: 8907 - 6
Naik S.Kavala V.Gopinath R.Patel BK. ARKIVOC 2006, (i): 119 - 7
Mondal E.Sahu PR.Bose G.Khan AT. Tetrahedron Lett. 2002, 43: 2843 - 8
Gosain J.Sharma PK. Indian Acad. Sci. (Chem. Sci.) 2003, 115: 135 - 9
Kavala V.Patel BK. Eur. J. Org. Chem. 2005, 441 - 10
Naik S.Gopinath R.Patel BK. Tetrahedron Lett. 2001, 42: 7679