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Synthesis of 1,2-dibromoalkanes (dibromination)
Recent Literature
The combination of DMSO and oxalyl bromide is a highly efficient
brominating reagent for various alkenes, alkynes and ketones. This bromination
offers mild conditions, low cost,
short reaction times, and provides dibromides and α-bromoketones in excellent yields.
R. Ding, J. Li, W. Jiao, M. Han, Y. Liu, H. Tian, B. Sun, Synthesis, 2018, 50,
4325-4335.
Stereoselective halogenations of alkenes and alkynes can be conducted in
room-temperature ionic liquids, 1-butyl-3-methylimidazolium hexafluorophosphate,
1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium
bromide, and 1-butyl-3-methylimidazolium chloride as "green" recyclable
alternatives to chlorinated solvents.
C. Chiappe, D. Capraro, V. Conte, D. Pieraccini,
Org. Lett., 2001, 3, 1061-1063.
The use of Selectfluor as an oxidant and tetrabutylammonium bromide/chloride
salts as a halogen source enables a metal-free and molecular halogen
reagent-free dihomohalogenation methodology. This effective strategy provides
various fluorine-free halogenated products easily in quantitative yields from
alkenes, alkynes, and natural products.
Z. Dağalan, R. Koçak, A. Daştan, B. Nişancı, Org. Lett., 2022, 24,
8261-8264.
Tetrapropylammonium nonabromide (Pr4NBr9) is a solid
reagent for rapid bromination reactions of various substrates. The reagent
exhibits reactivity similar to that of elemental bromine, but shows higher
selectivity and it is easier and safer to store and to handle.
T. M. Beck, H. Haller, J. Streuff, S. Riedel, Synthesis, 2014, 46,
740-747.
Organocatalytic stereospecific dibromination of various functionalized alkenes
was achieved using a simple thiourea catalyst and 1,3-dibromo
5,5-dimethylhydantoin as a stable, inexpensive halogen source at room
temperature. The procedure was extended to alkynes and aromatic rings and to
dichlorination reactions by using the 1,3-dichloro hydantoin derivative.
G. Hernández-Torres, B. Tan, C. F. Barbas III, Org. Lett., 2012,
14, 1858-1861.
Bromination of alkenes, alkynes, and anilines has efficiently been carried out
at room temperature in short reaction times using potassium bromide and
orthoperiodic acid in dichloromethane-water (1:1) to prepare the corresponding
brominated compounds with excellent yields.
A. Khazaei, M. A. Zolfigol, E. Kolvari, N. Koukabia, H. Soltania, F. Komakia, Synthesis, 2009,
3672-3676.
In an oxidative bromination of alkenes to 1,2-dibromo alkanes with HBr, dimethyl
sulfoxide serves as the oxidant as well as cosolvent. Whereas simple olefins are
brominated in very good yields, three of six styrene derivatives yielded
bromohydrins under the reaction conditions.
M. Karki, J. Magolan, J. Org. Chem.,
2015,
80, 3701-3707.
In bromination of alkenes by dibromine and dealkylation of aromatic ethers
by boron tribromide, a fluorous phase acts as a liquid membrane permitting
passive transport of the reagents at the bottom to the top layer involving
the substrates, thereby regulating the reactions.
I. Ryu, H. Matsubara, S. Yasuda, H. Nakamura, D. P. Curran, J. Am. Chem. Soc., 2002,
124, 12946-12947.
A Ph3P/I--promoted dihalogenation of epoxides provides
1,2-dihalides in the presence of XCH2CH2X (X = Cl or Br)
as the solvent and halogen source. All reagents are widely available and easy to
handle. The protocol offers mild conditions and operational simplicity.
J. Long, J. Chen, R. Li, Z. Liu, X. Xiao, J.-H. Ling, X. Zheng, J.-C. Xiao, Synlett, 2019,
30,
181-184.
An efficient two-step protocol that employs readily available terminal alkenes
as starting materials enables a highly regio- and stereoselective synthesis of
various allylic acetates. This method affords linear (E)-isomers and
tolerates several functional groups including halogen-containing molecules. For
other weak oxygen, carbon, nitrogen, and sulfur nucleophiles, adducts were
obtained in very good yields too.
X. Huang, B. Fulton, K. White, A. Bugarin, Org. Lett.,
2015,
17, 2594-2597.
Unsaturated compounds such as alkenes, alkynes, allenes, and
methylenecyclopropanes (MCPs) can be dibrominated within minutes by NBS and
lithium bromide in THF at room temperature in good to excellent yields under
mild conditions.
L.-X. Shao, M. Shi, Synlett,
2006, 1269-1271.
A direct 1,2-dibromination of alkenes with 1,3-dibromo-5,5-dimethylhydantoin
(DBDMH) as bromine source proceeds under mild reaction conditions without the
use of a catalyst and an external oxidant. Various sorts of alkene substrates
are transformed into the corresponding 1,2-dibrominated products in good to
excellent yields and exclusive diastereoselectivity.
L. Wang, L. Zhai, J. Chen, Y. Gong, P. Wang, H. Li, X. She, J. Org. Chem., 2022, 87,
3177-3183.
In an efficient one-pot method for the syntheses of di- and polybrominated
esters from readily available aldehydes starting with a Wittig reaction, the in
situ generated byproduct PPh3O mediates a subsequent bromination with
oxalyl bromide and greatly improves the efficiency of the cascade reaction.
T.-Y. Hu, H. Wei, Y.-C. Luo, Y. Wang, Z.-Y. Wang, P.-F. Xu, J. Org. Chem.,
2016,
81, 2730-2736.
Oxidative
bromination of different types of olefins using Selectfluor/KBr afforded addition,
monobromo-substituted, or Hunsdiecker-Borodin reaction products in good yields.
C. Ye, J. M. Shreeve, J. Org. Chem.,
2004,
69, 8561-8563.
An efficient method allows the construction of 2,6-cis-4,5-dibromo-tetrasubstituted
tetrahydropyran rings with well-controlled stereochemistry in good yields.
F. Liu, T.-P. Loh, Org. Lett., 2007,
9, 2063-2066.
The use of NaSO2CF3 and NaBrO3 enables a free-radical
bromotrifluoromethylation of olefins. Sodium bromate acts
not only as a single-electron oxidant but also as a bromine source.
Z.-Q. Liu, D. Liu, J. Org. Chem.,
2017, 82, 1649-1656.