A simple and efficient bromoformyloxylation and bromoacetoxylation reaction using TsNBr2

Article abstract of DOI:10.1016/j.tetlet.2011.11.138

Bromoformyloxylation and bromoacetoxylation of olefins proceed smoothly and instantaneously in the presence of N,N-dibromo-p-toluene sulfonamide without any catalyst. The one step reactions can be carried out with all kinds of olefins in high yield and hi

Full text of DOI:10.1016/j.tetlet.2011.11.138

Tetrahedron Letters 53 (2012) 758–761
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A simple and efficient bromoformyloxylation and bromoacetoxylation
reaction using TsNBr2
⇑
Indranirekha Saikia, Kamal Krishna Rajbongshi, Prodeep Phukan
Department of Chemistry, Gauhati University, Guwahati 781014, Assam, India
a r t i c l e i n f o
a b s t r a c t
Article history:
Bromoformyloxylation and bromoacetoxylation of olefins proceed smoothly and instantaneously in the
presence of N,N-dibromo-p-toluene sulfonamide without any catalyst. The one step reactions can be carried
out with all kinds of olefins in high yield and high regio and stereoselectivities.
Ó 2011 Elsevier Ltd. All rights reserved.
Received 27 September 2011
Revised 26 November 2011
Accepted 29 November 2011
Available online 7 December 2011
Keywords:
TsNBr2
Bromoformyloxylation
Bromoacetoxylation
Cohalogenation
The vicinal functionalizationof alkenes is an importantprocess in
synthetic organic chemistry. Among the several methodologies
found in the literature,1 halofunctionalization2 of alkenes toward
synthetically useful substrates attract much more attention. Such
type of reactions, also termed as ‘cohalogenation’ uses a combina-
tion of positive halogen source and appropriate nucleophile sources
such as water, alcohols, or acids.3 These reactions are attractive tools
to produce vicinal halo-functionalized compounds regioselectively,
which are useful intermediates for diverse organic transformations.
For example, chloroformyloxylation of olefins is synthetically useful
in order to obtain bifunctionalities with regioselectivity.4
Literature study reveals that limited attempts have been made
to explore this particular type of reaction. Using Vilsmeier reagent,
Ziegenbein et al. synthesised chloroformyloxylated product from
epoxides.5 Kim et al. synthesised chloroformylloxylated product
using HCl and DMF in the presence of an oxidant such as m-CPBA
or oxone.6 This procedure requires HCl gas in DMF besides hazard-
ous m-CPBA. N-halosuccinimides have also been used as halogen
source for such type of reactions.7 This reagent produces low yields
of the desired product after long reaction hours. Takemura studied
bromoformyloxylation using N,N-dibromobenzene sulfonamide in
the presence of 99% formic acid in chloroform at low temperarure.8
such as cinnamates and chalcones. Trichloroisocyanuric acid
(TCCA),9,10 I2/Fe(III) salts9,11 were also used by the same group
for the synthesis of other haloformates.
Another cohalogenation reaction is the bromoacetoxylation
reaction where vicinal bromo acetoxy products are synthesized.
This reaction also received scant attention in the literature. de Al-
meida et al. synthesised some compounds using tribromoisoc-
yanuric acid as the brominating agent.12 Yeung and co-workers
used NBS for bromoacetoxylation reaction in the presence of
molecular sieves as catalysts.13 A number of limitations such as
long reaction time, requirement of dark conditions, and high cata-
lyst loading make this procedure inconvenient. Using NaBr as bro-
mine source, Pandit isolated a few bromoacetoxylated products in
the presence of PhI(OAc)2 as oxidant in the presence of CTAB in
DCM.14 Negoro found that, vicinal bromo actoxy product forms
in low yields in a reaction of styrene with tetrabutyl ammonium
dichlorobromate in acetic acid.15 Other methods such as haloeste-
rification of diols16 and acetylation of corresponding vicinal halo-
hydrins17 were also reported. However, these methods require
the synthesis of precursor diols or halohydrins from corresponding
olefins.
We sought to develop a procedure for cohalogenation reaction
which is simple and trouble-free and can provide a better yield
in a shorter time period. In continuation of our investigations on
various organic transformations using N,N-dibromo-p-toluenesul-
fonamide (TsNBr2),18 we report herein the synthesis of formyloxy
bromides and acetyloxy bromides (Scheme 1).
This reaction was found to be very slow in case of a,b unsaturated
esters, which produces low yields of the product after several
hours of reaction. N-Bromosaccharin (NBSac) has been successfully
utilized by de Mattos for bromoformyloxylation of simple alkenes.9
However, efficacy of this reagent was not tested for other alkenes
To begin with, a study was carried out with styrene as a model
substrate. A reaction was carried out by adding TsNBr2 to the
solution of styrene in DMF. The whole process was carried out at
⇑
Corresponding author.
E-mail address: pphukan@yahoo.com (P. Phukan).
0040-4039/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2011.11.138

I. Saikia et al. / Tetrahedron Letters 53 (2012) 758–761
759
OCHO
Br
in 63% yields. Hence equimolar amount of TsNBr2 (based on the
substrate) was considered to be optimum for the reaction.
This process was extended to a variety of olefins.19 The reaction
was carried out using 1 mmol of olefin, 1 mmol of TsNBr2 in DMF
(2 mL) at room temperature followed by aqueous work-up. Results
are summarized in Table 1.
OCOCH3
R'
TsNBr2,
DMF, rt
TsNBr2
R'
R'
R
R
Aqueous
R
CH3COOH, rt
work up
Br
Scheme 1. Cohalogenation reaction using TsNBr2.
From Table 1 it is seen that not only the styrenes but also the ali-
phatic olefins react very smoothly to give the corresponding for-
myloxy bromides. Usually the a,b unsaturated compounds are not
room temperature under nitrogen atmosphere. The reaction was
studied by using 1 equiv of TsNBr2 (based on the olefinic sub-
strate). We observed that after addition; the olefin disappears
instantaneously in an exothermic process, which was confirmed
by monitoring the reaction by TLC. The reaction mixture was stir-
red for another 10 min. After usual aqueous work-up, and chro-
matographic purification, corresponding formyloxy bromide was
obtained in an 85% yield. When the reaction was further examined
using 0.5 equiv of TsNBr2 the corresponding product was obtained
so reactive species. In our case, cinnamate, chalcone as well as acry-
lates also gave encouraging results. From the NMR study, it was
confirmed that the reaction was highly regio and stereoselective.
After successful isolation of the formyloxy bromides, we chan-
ged the solvent of the model reaction, from DMF to acetic acid,
using styrene as substrate under the same reaction condition.19
We found pronounced effect on changing the media, where OAc
group is transferred along with the bromine and acetyloxy bro-
mide was isolated. We observed that the reaction produces the
Table 1
Bromoformyloxylation reaction using TsNBr2
Sl. No.
1
Substrate
Product
Yeilda
85
Ref.
8
OCHO
Br
OCHO
2
3
4
84
79
78
—
—
—
Cl
Br
Cl
Br
OCHO
Br
OCHO
Br
5
6
86
80
8,9
—
OCHO
Br
OCHO
OC2H5
O
OCHO
Br
O
7
86
—
OC2H5
OCHO
8
9
88
91
8,9
8
Br
O
OCHO O
OC2H
O
OC2H5
5
Br
OCHO
O
10
85
—
Cl
Cl
Br
a
isolated yield after chromatographic purification.

760
I. Saikia et al. / Tetrahedron Letters 53 (2012) 758–761
Table 2
Bromoacetoxylation reaction using TsNBr2
Sl. No.
11
Substrate
Product
Yielda
88
Ref.
13
OAc
Br
OAc
12
13
14
78
95
76
17a
15
Br
Br
Br
OAc
CH3
Br
OAc
13
Br
Br
15
75
16
OAc
OAc
16
17
76
86
13
14
Br
OAc
O
O
OC2H5
OC2H5
O
Br
OAc
O
OCH
OCH3
18
19
3
80
82
—
Br
OAc
Br
Br
O
O
OCH
OCH
3
3
17b
Br
H3CO
H3CO
a
Isolated yield after chromatographic purification.
corresponding bromo acetyloxy products instantaneously. After
initial success, attempts were made taking other olefins as subs-
rates and we were able to isolate different acetyloxy bromides in
excellent yields. Results are summarized in Table 2. In this case
also the reaction was found to be regio- and stereoselective.
In summary, we have developed a very efficient, quick, and sim-
ple procedure for the bromoformyloxylation as well as bromoacet-
oxylation of olefins. The procedure produces formyloxy bromides
and acetyloxy bromides instantaneously from olefins. All kinds of
olefins such as styrene, cinnamate, acrylate, chalcone, aliphatic ole-
fin etc. produce corresponding cohalogenated products in excellent
yields.
References and notes
1. Recent example. (a) Singh, S.; Singh, B. Ind. Eng. Chem. Res. 2007, 46, 983–986;
(b) Taber, D. F.; Liang, J.-I. J. Org. Chem. 2007, 72, 431–434; (c) Minakata, S.;
Yoneda, Y.; Oderaotoshi, Y.; Komatsu, M. Org. Lett. 2006, 8, 967–969; (d) Yeung,
Y.-Y.; Gao, X.; Corey, E. J. J. Am. Chem. Soc. 2006, 128, 9644–9645; (e) Urankar,
D.; Rutar, I.; Modec, B.; Dolenc, D. Eur. J. Org. Chem. 2005, 11, 2349–2353; (f)
Muñiz, K. New J. Chem. 2005, 29, 1371–1385.
2. (a) Damin, B.; Garapon, J.; Sillion, B. Synthesis 1981, 362–363; (b) Damin, B.;
Garapon, J.; Sillion, B. Tetrahedron Lett. 1980, 21, 1709–1710; (c) Rolston, J. H.;
Yates, K. J. Am. Chem. Soc. 1969, 91, 1469–1476; (d) Dewkar, G. K.; Narina, S. V.;
Sudalai, A. Org. Lett. 2003, 5, 4501–4504.
3. (a) Weber, F. C.; Hennion, G. F.; Vogt, R. R. J. Am. Chem. Soc. 1939, 61,
1457–1458; (b) Irwin, C. F.; Hennion, G. F. J. Am. Chem. Soc. 1941, 63,
858–860.
4. (a) Roocker, A.; Radzitzky, P. Bull. Soc. Chim. Belg. 1970, 79, 531; (b) Micev, I.;
Christova, N.; Pomakova, R.; Panajotova, B.; Iovchev, A. Z. Chem. 1975, 15, 191
(chem abstr. 83, 113285d); (c) Micev, I.; Christova, N.; Panajotova, B.;
Jovtscheff, A. Chem. Ber. 1973, 106, 606–610; (d) Kim, J. N.; Kim, H. R.; Ryu, E.
K. Synth. Commun. 1992, 22, 2521–2525.
Acknowledgments
Financial Support from DST (Grant No. SR/S1/RFPC-07/2006) is
gratefully acknowledged. IS thanks CSIR for senior research fellow-
ship. We are thankful to the reviewer for valuable suggestions.
5. Ziegenbein, W.; Franke, W. Chem. Ber. 1960, 93, 1681–1683.
6. (a) Kim, H. R.; Kim, J. N.; Park, H. J.; Ryu, E. K. Bull. Korean. Chem. Soc. 1997, 18,
110–111; (b) Kim, J. N.; Son, J. S.; Kim, H. R.; Ryu, E. K. Bull. Korean. Chem. Soc.
1998, 19, 812–813.
7. (a) Dalton, D. R.; Smith, R. C., Jr.; Jones, D. G. Tetrahedron 1970, 26, 575–581; (b)
Hamm, S.; Hennig, L.; Findeisen, M.; Müller, D.; Welzel, P. Tetrahedron 2000, 56,
1345–1348.
Supplementary data
8. (a) Niizato, H.; Ueno, Y.; Takemura, S. Chem. Pharm. Bull. 1972, 20, 2707–2709;
(b) Ueno, Y.; Yamasaki, A.; Terauchi, H.; Takemura, S. Chem. Pharm. Bull. 1974,
22, 1646–1651.
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.tetlet.2011.11.138.

I. Saikia et al. / Tetrahedron Letters 53 (2012) 758–761
761
9. de Souza, A. V. A.; Mendonça, G. F.; Bernini, R. B.; de Mattos, M. C. S. J. Braz.
Chem. Soc. 2007, 18, 1575–1579.
10. Mendonça, G. F.; Sanseverino, A. M.; de Mattos, M. C. S. Synthesis 2003, 45–48.
11. de Mattos, M. C. S.; Sanseverino, A. M. J. Chem. Res. 2004, 9, 638–639.
12. Almeida, L. S.; Esteves, P. M.; Marcio, C. S.; de Mattos, M. C. S. Synlett 2006, 10,
1515–1518.
13. Chen, F.; Jiang, X.; Cheng, Er. J.; Yeung, Y.-Y. Tetrahedron Lett. 2010, 51, 3433–
3435.
14. Pandit, P.; Gayen, K. S.; Khamarui, S.; Chatterjee, N.; Maiti, D. K. Chem. Commun.
2011, 47, 6933–6935.
15. Negoro, T.; Ikeda, Y. Bull. Chem. Soc. Jpn. 1986, 59, 3519–3522.
16. Oromí-Farrús, M.; Eras, J.; Villorbina, G.; Illorbina, M.; Torres, M.; Llops-Mestre,
V.; Welton, T.; Canela, R. Anal. Sci. 2008, 24, 1341–1345.
17. (a) Basavaiah, D.; Reddy, G. J.; Chandrashekar, V. Tetrahedron: Asymmetry 2001,
12, 685–689; (b) Anand, N.; Kapoor, M.; Koul, S.; Taneja, S. C.; Sharma, R. L.;
Qazi, G. N. Tetrahedron: Asymmetry 2004, 15, 3131–3138.
18. (a) Prodeep Phukan, P.; Chakraborty, P.; Kataki, D. J. Org. Chem. 2006, 71, 7533–
7537; (b) Saikia, I.; Phukan, P. Tetrahedron Lett. 2009, 50, 5083–5087; (c) Saikia,
I.; Chakraborty, P.; Phukan, P. ARKIVOC 2009, 8, 281–286; (d) Saikia, I.;
Kashyap, B.; Phukan, P. Synth. Commun. 2010, 40, 2647–2652; (e) Saikia, I.;
Kashyap, B.; Phukan, P. Chem. Commun. 2011, 47, 2967–2969.
19. Experimental procedure: To a solution of olefin (1 mmol) in 2 mL of DMF (or
acetic acid), TsNBr2 (1 mmol) was added under nitrogen atmosphere and
stirred. After 10 min of reaction, sodium thiosulfate (200 mg approx.) was
added followed by the addition of water (5 mL). The reaction mixture was
stirred for 15 min and taken up in ethyl acetate. Organic layer was separated,
washed with brine (saturated sodium bicarbonate solution and brine for
Bromoacetoxylation), and dried over anhydrous sodium sulfate, and
concentrated. The crude product was purified by flash chromatography on
silica gel (230–400 mesh) with petroleum ether/ethyl acetate as eluent.