α-Sulfonyloxylation of 1,3-dicarbonyl compounds utilizing hypervalent iodine(iii) reagent: Construction of quaternary carbon center

Article abstract of DOI:10.1080/00397911.2018.1472281

An efficient method for direct α-sulfonyloxylation of various sterically hindered 1,3-dicarbonyl compounds has been developed under mild reaction conditions. The yields of desired products is up to 90% and a plausible mechanism was accordingly proposed.

Full text of DOI:10.1080/00397911.2018.1472281

Synthetic Communications
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α-Sulfonyloxylation of 1,3-dicarbonyl compounds
utilizing hypervalent iodine(iii) reagent:
Construction of quaternary carbon center
Ruojuan Liu, Junzheng Wang, Wen Hu, Xiaohui Zhang & Yan Xiong
To cite this article: Ruojuan Liu, Junzheng Wang, Wen Hu, Xiaohui Zhang & Yan Xiong (2018): α-
Sulfonyloxylation of 1,3-dicarbonyl compounds utilizing hypervalent iodine(iii) reagent: Construction
of quaternary carbon center, Synthetic Communications, DOI: 10.1080/00397911.2018.1472281
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SYNTHETIC COMMUNICATIONSV
https://doi.org/10.1080/00397911.2018.1472281
a-Sulfonyloxylation of 1,3-dicarbonyl compounds utilizing
hypervalent iodine(iii) reagent: Construction of quaternary
carbon center
Ruojuan Liu, Junzheng Wang, Wen Hu, Xiaohui Zhang, and Yan Xiong
School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, China
ABSTRACT
ARTICLE HISTORY
Received 28 January 2018
An efficient method for direct a-sulfonyloxylation of various sterically
hindered 1,3-dicarbonyl compounds has been developed under mild
reaction conditions. The yields of desired products is up to 90% and
a plausible mechanism was accordingly proposed.
KEYWORDS
Dicarbonyl compounds;
hypervalent iodine; HTIB;
sulfonyloxy group;
a-sulfonyloxylation
GRAPHICAL ABSTRACT
Introduction
In past decades, hypervalent iodine compounds have been increasingly explored in
organic synthesis due to their efficient oxidizability and low toxicity.[1] Among them,
more “stabilized” iodine(III) reagents such as (diacetoxyiodo)benzene and [hydroxy(to-
syloxy)iodo]benzene (HTIB, Koser’s reagent) are widely employed in oxidation of
olefins,[2] ring contractions and expansions,[3] dearomatization of phenols,[4] synthesis of
iodonium salts,[5] and a-oxidation of carbonyl compounds.[6] On the basis of the high
utility of hypervalent iodine reagents, we have recently reported the efficient synthesis of
benzyl halides, cyanation of tertiary amine through oxidation-strecker reaction pathway
and silyl enol ethers by means of umpolung strategy, synthesis of benzoxazoles and
benzimidazoles via an oxidative rearrangement, intramolecular aminocyanation of
unactivated alkenes.[7] Meanwhile, the use of HTIB for the direct a-sulfonyloxylation of
enol derivatives and enolizable substrates has been reported extensively.[8] Moreover,
CONTACT Xiaohui Zhang
xiaohuizhang@cqu.edu.cn; Yan Xiong
Xiong@cqu.edu.cn
School of Chemistry and
Chemical Engineering, Chongqing University, Chongqing 400030, China.
Supplemental data for this article can be accessed on the publisher’s website.
ß 2018 Taylor & Francis

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R. LIU ET AL.
Scheme 1. a-Sulfonyloxylation of acetoacetate.
substituted versions of HTIB are used to vary the reactivity of the reagent.[9] The syn-
thetic route to HTIB is usually composed of two steps and high yields can be obtained
if performed the ligand exchange reaction under microwave irradiation or solvent-free
conditions.[10] And novel and efficient one-pot synthesis strategies have been reported
which ca avoid the need for expensive iodine(III) precursors and long reaction times.[11]
Togo and co-workers have carried out a study on the preparation of HTIBs bearing
other aromatics (thienyl, pyrazolyl, trifluoromethylphenyl, and bis(trifluoromethyl)-
phenyl) instead of a phenyl group.[12] Olofsson group has successfully prepared various
neutral and electron-rich HTIBs from iodine and arenes or from corresponding aryl
iodide via one-pot synthesis strategy.[13] However, there were very few studies about
obtaining HTIBs by using different sulfonyloxy groups instead of tosyloxy group which
provides alternative way to give new kind of iodine(III) reagents.[9]
Owing to the sulfonyloxy group as an effective leaving and protecting group can be
conveniently converted to other important functional groups,[14] a-sulfonyloxylation has
become increasingly important in organic synthetic chemistry. Among them, the most
widely studied is a-sulfonyloxylation of ketones, alcohol, and enol ether which provide a
one-pot convenient procedure for the synthesis of a wide range of heterocyclic com-
pounds like thiazoles, selenazoles, oxazoles, imidazoles avoiding the use of lachrymatory,
and toxic a-haloketones.[15] However, there were only a few in-depth researches about
a-sulfonyloxylation of 1,3-dicarbonyl compounds which also can be used for preparing
heterocyclic compounds and derivatives.[16] To our knowledge, the tautomerism of 1,3-
dicarbonyl compounds to enol would alter the spatial orientation of a-sulfonyloxyl
group at random after sulfonyloxylation.[17] Thus, we take the 2-substituted versions as
substrates instead of 1,3-dicarbonyl compounds to overcome this shortcoming. In the
literature search, a-tosyloxylation of 2-methyl-1,3-dicarbonyl compounds was reported
only in one case, which was assisted by microwave in 1988.[18] Therefore, it is highly
desirable to develop an efficient and convenient method for direct introduction of
sulfonyloxy groups of 2-methyl-1,3-dicarbonyl compounds. In our previous work,
nucleophilic imidoesterification of dicarbonyl compounds with cyanatobenzenes and
electrophilic a-cyanation of dicarbonyl compounds have been developed,[19] at the same

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Table 1. Optimization of reaction conditions.a
Entry HTIB (equiv)
Solvent
V (mL) T (oC) t (h) Yield (%)b
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
1.5
1.5
1.5
1.5
1.0
1.2
1.8
2.0
1.8
1.8
1.8
1.8
1.8
1.8
1.8
1.8
1.8
1.8
1.8
1.8
1.8
1.8
1.8
1.8
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
DCM
CHCl3
PhCH3
EtOAc
Et2O
DMSO
CH3OH
THF
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.0
2.0
1.5
1.5
1.5
1.5
1.5
1.5
0
25
40
60
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
1
4
6
8
4
4
17
83
85
81
73
81
85
82
75
67
48
37
12
trace
trace
c
-
83
80
58
90
85
81
trace
77
MeCN:H2O ¼ 9:1(v/v)
No Solvent
aConditions: ethyl 2-methyl-3-oxobutanoate (1a, 0.5mmol) and HTIB (2a, speci-
fied) in solvent (mL, specified).
bIsolated yields.
cComplex mixture.
Table 2. Screening of reaction additives.a
Entry
Additiveb
Yield (%)c
1
2
3
4
5
6
4 Å MS
NEt3
K2CO3
CH3COOH
BF3ꢀOEt2
Na2SO4
11
trace
d
-
53
81
79
aConditions: ethyl 2-methyl-3-oxobutanoate (0.5mmol) and HTIB (1.8 equiv) in MeCN
(1.5 mL) at room temperature for 4 h.
bAmount of additive: entry 1: 20 wt% of substrates; entries 2–6: 20 mol% of substrates.
cIsolated yields.
dComplex mixture.
time, taking our groups’ great interest of using hypervalent iodine reagents for synthesis
into account. Herein, we would like to investigate the a-sulfonyloxylation of 1,3-dicar-
bonyl compounds towards construction of quaternary carbon center with hypervalent
iodine(III) reagents containing different sulfonyloxy groups (Scheme 1).[20]

4
R. LIU ET AL.
Table 3. Preparations of different hypervalent iodine reagents.a
2a, 84%
2d, 52%
2b, 54%
2c, 76%
2e, 65%
2f, 56%
aConditions: iodobenzene (10.0 mmol), sulfonic acid (1.1 equiv) and m-CPBA (1.1 equiv)
in CHCl3 (10.0 mL) at room temperature for 2 h; isolated yields by filtration.
Results and discussion
The optimization studies on the a-sulfonyloxylation reaction were initiated by using
dicarbonyl compound ethyl 2-methyl-3-oxobutanoate 1a and hypervalent iodine reagent
[hydroxy(tosyloxy)iodo]benzene 2a in MeCN. As depicted in Table 1, the effect of tem-
perature was first examined; as a result, the reaction was found to be restrained seriously
at 0 ꢁC (Table 1, entry 1) and a continuous increase of yield was made when the tem-
perature was elevated to 60 ꢁC (Table 1, entries 2–4). Although the temperature of 40 ꢁC
resulted in the best yield (85%) by comparing with others, room temperature still gave a
competitive yield of 83% (Table 1, entry 2). The effect of the amount of HTIB were then
examined at room temperature, 1.0–2.0 equivalents were tested (Table 1, entries 2 and
5–8), and a satisfactory 85% yield was obtained when the loading of HTIB was increased
to 1.8 equivalents (Table 1, entry 7). Then, various strong polar and non-polar solvents
were screened subsequently. The results showed that MeCN, DCM, and CHCl3 gave the
products in 67%–85% yields, in which MeCN was the most suitable one (Table 1, entries
7, 9, and 10). Whereas toluene, EtOAc, and Et2O just gave moderate yields and only
trace desired product was observed in DMSO and CH3OH (Table 1, entries 11–15).
When THF was utilized as the solvent, the reaction went complex and the attempt to
separate the product failed (Table 1, entry 16). On testing the effect of the volume of
solvent, 1.5 mL of MeCN proved to be the most effective one. Nevertheless, either diluted
or concentrated reaction mixtures were not favorable and led to a lower yield (Table 1,
entries 7, 17, and 18). The effects of the reaction time were then investigated and the
results indicated that prolonging the reaction time to 4 h gave the best yield of 90%
(Table 1, entries 19–22). This reaction proved to be water-sensitive as well. When a

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Table 4. Preparation of a-sulfonyloxylation of dicarbonyl compounds.a
3a, 90%
3b, 89%
3c, 80%
3d, 67%
3g, 85%
3e, 64%
3h, 72%
3f, 86%
3i, 84%
3j, 30%
3k, 68%
aConditions: dicarbonyl compound (1, 0.5 mmol) and hypervalent iodine (2, 1.8 equiv)
in MeCN (1.5 mL) at room temperature for 4 h; isolated yields.
9:1(v/v) mixture of MeCN–H2O was used as the solvent at room temperature for 4 h, the
yield of the desired product 3a was sharply reduced to trace (Table 1, entry 23). In add-
ition, the reaction has been carried out under the solvent-free condition, the yield of the
target product was diminished to 77%. This observation suggested that solvent was
important to the a-sulfonyloxylation reaction (Table 1, entry 24).
To further improve the reactivity, varieties of common additives were examined and
the result revealed that the transformation procedure was heavily inhibited by 4 Å of
molecular sieves (Table 2, entry 1). Then, basic additives such as TEA and K2CO3 were
also examined and they were both ineffective (Table 2, entries 2–3). Using acid such as
acetic acid and BF3 ꢀ OEt2 as additives delivered lower yields of 53% and 81%,

6
R. LIU ET AL.
Figure 1. Reaction mechanism proposed for a-sulfonyloxylation.
respectively (Table 2, entries 4–5). Although our former study has demonstrated that
Na2SO4 was beneficial on the cyanation of a tertiary amine,[7b] the addition of Na2SO4
was not found to be favorable for the a-sulfonyloxylation reaction and led to a lower
yield of 79% (Table 2, entry 6). The attempt to improve the yields by the addition of
additives was unsuccessful.
Meanwhile, when iodobenzene was treated with m-CPBA in the presence of various
sulfonic acid in chloroform at room temperature for two hours, the corresponding
hypervalent iodine compounds 2a–f was successfully obtained in moderate to good
yields ranging from 52% to 84%. (Table 3) The synthesized compounds 2 were charac-
terized by comparing their spectral properties with those reported in the literature.
With the optimal conditions for a-sulfonyloxylation reaction in hand, different classes
of 1,3-dicarbonyl compounds were examined with compounds 2a–f as summarized in
Table 4. With regard to the effect of different hypervalent iodines, those bearing elec-
tron-donating substituents like mono- and di- methyl on the aromatic ring of sulfony-
loxy group gave the corresponding products excellent yields of 90% and 89%,
respectively (3a and 3b). As for non-substituted aromatic ring resulted in a lower yield
of 80% (3c). However, the aromatic ring with electron-withdrawing groups such as nitro
and chloro groups led to the yields at the level of about 60%, respectively (3d and 3e).
The methylsulfonyloxy group possessing electron-donating nature and small steric hin-
drance provided an excellent yield of 86% (3f). Next, we chose HTIB 2a as sulfonyloxy-
lation reagent for different dicarbonyl compounds. Linear (3g), branched (3h), and
cyclopropyl (3i) substituted substrates responded to a-sulfonyloxylation products in
85%, 72%, and 84% yield, respectively. To our delight, ketones having cyclic (3j) and
fused ring (3k) gave rise to corresponding sulfonate in yield of 30% and 68%.
Based on earlier studies of ketones, b-dicarbonyl compounds, and silyl enol ethers
reacted with iodine(III) sulfonate reagents,[6,8] a plausible mechanism pathway for the
a-sulfonyloxylation of 2-methyl-1,3-dicarbonyl compounds were depicted in Figure 1.

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7
Firstly, [hydroxyl (sulfonyloxy)]iodobenzene 2 combined with the enol form of dicar-
bonyl compound 1 to give a-iodine(III) substituted dicarbonyl intermediate accompa-
nied with the release of sulfonyloxy anion. Then, the intermediate was followed by the
nucleophilic attack of sulfonyloxy anion upon the a-carbon-bearing iodine (III) struc-
tural unit to yield the corresponding a-sulfonyloxylated products with the concomitant
reductive elimination of iodobenzene.
Conclusions
Utilization of various types of [hydroxyl (sulfonyloxy)]iodobenzene prepared from iodo-
benzene, sulfonic acids, and m-CPBA, we have developed an efficient method for direct
a-sulfonyloxylation of a wide range of sterically hindered 1,3-dicarbonyl compounds
under mild reaction conditions. A series of a-sulfonyloxy dicarbonyl compounds were
produced in yields of up to 90% and a plausible mechanism was proposed accordingly
to interpret the observed reactivities.
Experimental
NMR spectra were recorded on a Bruker Avance 500 MHz NMR spectrometer with
1
DMSO-d6 (d ¼ 39.2 ppm) or CDCl3 (d ¼ 77.2 ppm) as solvent at 20–25 ꢁC. H NMR
data are reported in parts per million (ppm) using TMS (d ¼ 0.00 ppm) as the internal
standard, as follows: chemical shift, multiplicity (s ¼ singlet, d ¼ double, t ¼ triplet,
q ¼ quartet, m ¼ multiplet), coupling constants (J, Hz) and integration. The data of 13C
NMR data are reported in parts per million. Melting points were measured with a
€
Kofler apparatus. IR spectra were recorded on Nicolet 550II spectrophotometer. HRMS
(ESI) data were measured on an Agilent 6510 Q-TOF mass spectrometer. Reactions
were monitored by TLC and column chromatography was performed using silica gel.
Commercially available reagents were used without further purification unless other-
wise specified.
General procedure for synthesis of hypervalent iodine compounds (2a–f)
In a round-bottom flask, iodine benzene (10.0 mmol), sulfonic acid (11.0 mmol), and
chloroform (10.0 mL) were added successively and the mixture was stirred for 5 minutes
at room temperature. Then m-CPBA (11.0 mmol) was put in slowly and the reaction
mixture was stirred at room temperature. After the reaction, the reaction mixture was
filtered, and the solid was washed with ether.
General procedure of a-sulfonyloxylation (3a–k)
In a round-bottom flask, hypervalent iodine 2 (0.9 mmol) and acetoacetate 1 (0.5 mmol)
were dissolved in CH3CN (1.5 mL). The reaction mixture was stirred at room tempera-
ture for 4h and the solvent was removed under reduced pressure. The products
were isolated by column chromatography of the residue on silica gel to give the
corresponding products 3a–k.

8
R. LIU ET AL.
Funding
We thank the National Natural Science Foundation of China (No. 21372265) for finan-
cial surport.
References
[1] (a) Varvoglis, A. Synthesis. 1984, 9, 709–726. (b) Moriarty, R. M.; Prakash, O. Acc. Chem.
Res. 1986, 19, 244–250. (c) Ochiai, M. Rev. Heteroat. Chem. 1989, 2, 92–111.
(d) Merkushev, E. B. Russ. Chem. Rev. (Eng. Transl.) 1987, 56, 826–845. (e) Stang, P. J.;
Zhdankin, V. V. Chem. Rev. 1996, 96, 1123–1178. (f) Umemoto, T. Chem. Rev. 1996, 96,
1757–1778. (g) Varvoglis, A. Tetrahedron 1997, 53, 1179–1255. (h) Zhdankin, V. V.;
Stang, P. J. Tetrahedron 1998, 54, 10927–10966. (i) Wirth, T.; Hirt, U. H. Synthesis 1999,
1271–1287. (j) Koser, G. F. Aldrichimica Acta 2001, 34, 89–102. (k) Zhdankin, V. V.;
Stang, P. J. Chem. Rev. 2002, 102, 2523–2584. (l) Wirth, T. Angew. Chem. Int. Chem.
2005, 44, 3656–3665. (m) Richardson, R. D.; Wirth, T. Angew. Chem. Int. Chem. 2006, 45,
4402–4404. (n) Dohi, T.; Morimoto, K.; Maruyama, A.; Kita, Y. Org. Lett. 2006, 8,
2017–2010. (o) Bose, D. S.; Idrees, M. J. Org. Chem. 2006, 71, 8261–8263. (p) Dohi, T.;
Morimoto, K.; Takenaga, Naoko., Goto, A.; Maruyama, A.; Kiyono, Y.; Kita, Y. J. Org.
Chem. 2007, 72, 109–116. (q) Ochiai, M.; Miyamoto, K. Eur. J. Org. Chem. 2008, 25,
4229–4239. (r) Uyanik, M.; Ishihara, K. Chem. Commun. 2009, 16, 2086–2099.
[2] (a) Koser, G. F.; Rebrovic, L.; Wettach, R. H. J. Org. Chem. 1981, 46, 4324–4326.
(b) Rebrovic, L.; Koser, G. F. J. Org. Chem. 1984, 49, 2462–2472. (c) Ochiai, M.; Ito, T.;
Takahashi, H.; Nakanishi, A.; Toyonari, M.; Sueda, T.; Goto, S.; Shiro, M. J. Am. Chem.
Soc. 1996, 118, 7716–7730. (d) Dauban, P.; Dodd, R. H. Synlett 2003, 11, 1571–1586.
[3] (a) Takata, T.; Tajima, R.; Ando, W. J. Org. Chem. 1983, 48, 4764–4766. (b) Kita, Y.; Egi,
M.; Ohtsubo, M.; Saiki, T.; Takada, T.; Tohma, H. Chem. Commun. 1996, 2225–2227.
(c) Akai, S.; Okuno, T.; Takada, T.; Tohma, H.; Kita, Y. Heterocycles 1996, 42, 47–51.
(d) Tohma, H.; Watanabe, H.; Takizawa, S.; Maegawa, T.; Kita, Y. Heterocycles 1999, 51,
1785–1788. (e) Kita, Y.; Egi, M; Takada, T.; Tohma, H. Synthesis 1999, 5, 885–897.
(f) Chen, L. C.; Wang, H. M.; Kang, I. J. Heterocycles 1999, 51, 1437–1441. (g) Justik, M.
W.; Koser, G. F. Molecules 2005, 10, 217–225.
[4] (a) Kita, Y.; Takada, T.; Mihara, S.; Whelan, B. A.; Tohma, H. J. Org. Chem. 1995, 60,
7144–7148. (b) Takada, T.; Arisawa, M.; Gyoten, M.; Hamada, R.; Tohma, H.; Kita, Y. J.
Org. Chem. 1998, 63, 7698–7706. (c) Krikorian, D.; Tarpanov, V.; Parushev, S.;
Mechkarova, P. Synthetic Commun. 2000, 30, 2833–2846.
[5] (a) Koser, G. F.; Wettach, R. H.; Smith, C. S. J. Org. Chem. 1980, 45, 1543–1544.
(b) Zhdankin, V. V.; Persichini III, P. J.; Cui, R.; Jin, Y. Synlett 2000, 5, 0719– 0721.
(c) Ochiai, M. J. Organometallic Chem. 2000, 611, 494–508. (d) Ren, K.; Malpert, J. H.;
Gu, H.; Li, H. Y.; Neckers, D. C. Tetrahedron 2002, 58, 5267–5273.
[6] (a) Moriarty, R. M.; Prakash, O.; Duncan, M. P. Synthesis 1985, 10, 943–944. (b) De Mico,
A.; Margarita, R.; Parlanti, L.; Vescovi, A.; Piancatelli, G. J. Org. Chem. 1997, 62,
6974–6977. (c) Tohma, H.; Takizawa, S.; Maegawa, T.; Kita, Y. Angew. Chem. Int. Ed.
2000, 39, 1306–1308. (d) Lee, J. C.; Lee, J. Y.; Lee, S.J. Tetrahedron Lett. 2004, 45,
4939–4941. (e) Karade, N. N.; Tiwari, G. B.; Huple, D. B. Synlett 2005, 13, 2039–2042.
(f) Guilbault, A. A., Legault, C. Y. ACS Catalysis 2012, 2, 219–222. (g) Guilbault, A. A.,
Basdevant, B., Wanie, V., Legault, C. Y. J. Org. Chem. 2012, 77, 11283–11295.
(h) Basdevant, B., Legault, C. Y. Organic letters, 2015, 17, 4918–4921.
[7] (a) Ling, X.; Xiong, Y.; Zhang, S.; Huang, R.; Zhang, X. Chin. Chem. Lett. 2013, 24, 45–48.
(b) Shen, H.; Zhang, X.; Liu, Q.; Pan, J.; Hu, W.; Xiong, Y.; Zhu, X. Tetrahedron Lett.
2015, 56, 5628–5631. (c) Shen, H.; Li, J.; Liu, Q.; Pan, J.; Huang, R.; Xiong, Y. J. Org.
Chem. 2015, 80, 7212–7218. (d) Zhang, X.; Huang, R.; Marrot, J.; Coeffard, V.; Xiong, Y.
Tetrahedron 2015, 71, 700–708. (e) Shen, H.; Deng, Q.; Liu, R.; F, Y.; Zheng, C.; Xiong, Y.
Org. Chem. Front. 2017, 4, 1806–1811.

R
SYNTHETIC COMMUNICATIONSV
9
[8] (a) Koser, G. F.; Wettach, R. H. J. Org. Chem. 1976, 41, 3609–3611. (b) Koser, G. F.;
Relenyi, A. G.; Kalos, A. N.; Rebrovic, L.; Wettach, R. H. J. Org. Chem. 1982, 47,
2487–2489. (c) Moriaraty, R. M.; Penmasta, R.; Awasthi, A. K.; Epa, W. R.; Prakash, I. J.
Org. Chem. 1989, 54, 1101–1104. (d) Bovonsombat, P.; Angara, G. J.; NcNelis, E.
Tetrahedron Lett. 1994, 35, 6787–6790. (e) Lee, J. C.; Park, H. J.; Park, J. Y. Tetrahedron
Lett. 2002, 43, 5661–5663. (f) Prakash, O.; Pannu, K.; Prakash, R.; Batra, A. Molecules
2006, 11, 523–527.
[9] (a) Koser, G. F.; Wettach, R. H. J. Org. Chem. 1977, 42, 1476–1578. (b) Yamamoto, Y.;
Togo, H. Synlett 2005, 16, 2486–2488. (c) Jalalian, N.; and Olofsson, B. Org. Synth. 2013,
90, 1–9.
[10] (a) Lee, J. C.; Choi, J. H. Synlett 2001, 2, 0234–0235. (b) Handy, S. T.; Okello, M. J. Org.
Chem. 2005, 70, 2874–2877. (c) Moroda, A.; Togo, H. Tetrahedron 2006, 62, 12408–12414.
[11] (a) Dohi, T.; Maruyama, A.; Yoshimura, M.; Morimoto, K.; Tohma, H.; Shiro, M.; Kita, Y.
Chem. Commun. 2005, 2205–2207. (b) Yu, J.; Cui, J.; Hou, X. S.; Liu, S. S.; Gao, W. C.;
Jiang, S.; Tian, J.; Zhang, C. Tetrahedron: Asymmetry 2011, 22, 2039–2055 (c) Zhang, B.;
Han, L.; Hu, J.; Yan, J. Tetrahedron Lett. 2014, 55, 5851–5854.
[12] Nabana, T.; Togo, H. J. Org. Chem. 2002, 67, 4362–4365.
[13] Merritt, E. A.; Carneiro, V. M. T.; Silva, L. F., Jr.; Olofsson, B. J. Org. Chem. 2010, 75,
7416–7419.
[14] (a) Moriarty, R. M.; Vaid, R. K.; Hopkins, T. E.; Vaid, B. K.; Prakash, O. Tetrahedron Lett.
1990, 31, 201–204. (b) Prakash, O.; Rani, N.; Sharma, P. K. Synlett 1994, 221–227.
(c) Prakash, O.; Saini, N.; Sharma, P. K. Heterocycles 1994, 38, 409–430. (d) Lee, J. C.; Jin,
Y. S. Synthetic commun. 1999, 29, 2769–2774. (e) Lee, J. C.; Kim, S.; Shin, W. C. Synthetic
Commun. 2000, 30, 4271–4275. (g) Uneno, M.; Togo, H. Synthesis 2004, 16, 2673–2677.
[15] (a) Moriarty, R. M.; Vaid, B. K.; Duncan, M. P.; Levy, S. G.; Prakash, O.; Goyal, S.
Synthesis 1992, 9, 845–846. (b) Prakash, O.; Goyal, S. Synthesis 1992, 7\, 629–630. (c) Kita,
Y.; Watanabe, H.; Egi, M.; Saiki, T.; Fukuoka, Y.; Tohma, H. J. Chem. Soc., Perkin Trans.
1, 1998, 635–636. (d) Kita, Y.; Egi, M.; Tohma, H. Chem. Commun. 1999, 2, 143–144.
[16] (a) Herrero, M. T.; Tellitu, I.; Domıꢀnguez, E.; Hernaꢀndez, S.; Moreno, I.; SanMartıꢀn, R.
Tetrahedron 2002, 58, 8581–8589. (b) John, O. R. S.; Killeen, N. M.; Knowles, D. A.; Yau,
S. C.; Bagley, M. C.; Tomkinson, N. C. O. Org. Lett. 2007, 9, 4009–4012. (c) Yamamoto,
Y.; Kawano, Y.; Toyb, P. H.; Togoa, H. Tetrahedron 2007, 63, 4680–4687.
[17] Ochiai, M.; Takeuchi, Y.; Katayama, T.; Sueda, T.; Miyamoto, K. J. Am. Chem. Soc. 2005,
127, 12244–12245.
[18] Lodaya, J. S.; Koser, G. F. J. Org. Chem. 1988, 53, 210–212.
[19] (a) Ma, H.; He, Y.; Huang, R. F.; Zhang, X. H.; Pan, J.; Li, J. Q.; He, C.; Ling, X. G.;
Wang, X. L.; Xiong, Y. Chin. Chem. Lett. 2014, 25, 1327–1330. (b) Akula, R.; Xiong, Y.;
Ibrahim, H. RSC Adv. 2013, 3, 10731–10735.
[20] The asymmetric version has been reported, and the racemic one keeps unreported until
now which utilizes isolated HTIBs as sulfonyloxylation reagents. For asymmetric version,
see: Feng, Y. Y.; Huang, R. F.; Hu, L. Z.; Xiong, Y.; Coeffard, V. Synthesis 2016, 48,
2637–2644.