Iodine-catalyzed α,β-dehydrogenation of ketones and aldehydes generating conjugated enones and enals

Article abstract of DOI:10.1039/d0nj01244k

A transition metal-free α,β-dehydrogenation of ketones and aldehydes was developed. This reaction was conducted in a facile I₂/KI/DMSO system to produce the corresponding unsaturated compounds in good to high yields. The gram-scale experiment also indicated the potential synthetic value of this new reaction in organic synthesis. In the reaction, DMSO acted as both solvent and mild oxidant.

Full text of DOI:10.1039/d0nj01244k

View Article Online
View Journal
NJC
New Journal of Chemistry
Accepted Manuscript
A journal for new directions in chemistry
This article can be cited before page numbers have been issued, to do this please use: Y. Cao, L. Liu, T.
Huang and T. Chen, New J. Chem., 2020, DOI: 10.1039/D0NJ01244K.
Volume 42
Number
March 2018
Pages 3963-4776
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
6
21
NJC
New Journal of Chemistry
rsc.li/njc
A journal for new directions in chemistry
Accepted Manuscripts are published online shortly after acceptance,
before technical editing, formatting and proof reading. Using this free
service, authors can make their results available to the community, in
citable form, before we publish the edited article. We will replace this
Accepted Manuscript with the edited and formatted Advance Article as
soon as it is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
Please note that technical editing may introduce minor changes to the
text and/or graphics, which may alter content. The journal’s standard
Terms & Conditions and the Ethical guidelines still apply. In no event
shall the Royal Society of Chemistry be held responsible for any errors
or omissions in this Accepted Manuscript or any consequences arising
from the use of any information it contains.
ISSN 1144-2546
PAPER
Chechia Hu, Tzu-Jen Lin et al.
Yellowish and blue luminescent graphene oxide quantum dots
prepared via a microwave-assisted hydrothermal route using
H2O2 and KMnO4 as oxidizing agents
rsc.li/njc

Please do not adjust margins
Page 1 of 4
New Journal of Chemistry
1
2
3
4
5
6
7
View Article Online
DOI: 10.1039/D0NJ01244K
COMMUNICATION
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Iodine-Catalyzed α,β-Dehydrogenation of Ketones and Aldehydes
Generating Conjugated Enones and Enals
Received 00th January 20xx,
Accepted 00th January 20xx
a
b
b
a,b
Yuanjie Cao, Long Liu , Tianzeng Huang and Tieqiao Chen*
DOI: 10.1039/x0xx00000x
A transition metal-free ,-dehydrogenation of ketones and the C-H iodination forming the corresponding C-I
1
0
aldehydes was developed. This reaction was conducted in a facile intermediate. We envision that if the C-I species generated in
I2/KI/DMSO system to produce the corresponding unsaturated situ would undergo -elimination, the ,-dehydrogenation
compounds in good to high yields. The gram-scale experiment also can be realized under a metal-free reaction condition. After
indicated a potential synthetic value of this new reaction in extensive studies, we achieved such a reaction with use of the
organic synthesis. In the reaction, DMSO acted as both solvent readily available I2/KI as a catalyst and DMSO as a mild oxidant
and mild oxidant.
(Scheme 1d). Under the reaction conditions, a variety of
conjugated enones and enals were produced in moderate to
good yields. Compared with previous one-pot methods, this
reaction not only greatly decreased the cost, but also
overcame the contamination and purification issues of
products due to the use of special oxidants and (or) transition
metal catalysts.

,-Unsaturated ketones and aldehydes are important
structural units occurring in many natural products, synthetic
1
drugs, and material functional molecules. They are also
versatile building blocks for organic reactions such as Heck
2
coupling, Diels-Alder addition, and Micheal addition. Thus,
their efficient synthesis attracts much attention. Among the
established transformations, the ,-dehydrogenation of
Ketones would be one of the most straightforward methods.
Conventionally, the strategy was achieved through two steps
involving -functionalization and subsequently -elimination
Scheme 1a). The Pd-catalyzed Saegusa-type reactions
3
(
(
dehydrosilylation of silyl enol ethers) are also extensively used
4
to synthesize these compounds (Scheme 1b). Despite their
wide application, synthesis and purification of the synthetic
intermediates greatly decreased the total reaction efficiency.
In contrast, the direct ,-dehydrogenation is more step-
economical and gradually appeals interest of chemists. Early
works usually used over-stoichiometric special oxidants such
5
6
7
as SeO2, transition metal salts and IBX (2-iodoxybenzoic acid)
Scheme 1c). Recently, transition metal-catalyzed aerobic
(
oxidative strategy was adopted to this field and a big
achievement has been made (Scheme 1c).
I2/DMSO is a powerful catalytic oxidative system for C-H
8
Scheme 1. ,-Dehydrogenation of Ketones and Aldehydes Forming Conjugated
Enones and Enals.
9
functionalization. The key step involved in those reactions is
We started our work with the choice of 1,3-diphenylpropan-
1-one (1a) as a model reactant. As shown in Table 1, a mixture
of 1a in DMSO was heated in the presence of 2.5 mol% I2 at
a.
State Key Laboratory of Chemo / Biosensing and Chemometrics, College of
o
Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan,
130 C for 16 h, the expected unsaturated product 2a was
4
10082, China. E-mail: chentieqiao@hnu.edu.cn.
b.
produced in 67% yield (Table 1, entry 1). No reaction was
observed in the absence of iodine (Table 1, entry 2). The yield
was also not enhanced with a higher loading of iodine (Table 1,
entry 3). To our delight, the yield was increased to 78% by
adding 10 mol% KI (Table 1, entry 4). The loading of KI was
Key Laboratory of Ministry of Education for Advanced Materials in Tropical Island
Resources, College of Chemical Engineering and Technology, Hainan University,
Haikou, Hainan 570228, China.
Electronic Supplementary Information (ESI) available: [details of any
supplementary information available should be included here]. See
†
DOI: 10.1039/x0xx00000x
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 2 of 4
COMMUNICATION
subsequently investigated with 10 mol% amounts being the
Journal Name
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
substituents on the double bond were generatedVireewaAdrtiicllye.OTnlhinee
best choice (Table 1, entries 4-6). It should be noted that KI high yield would be ascribed to the strDoOnI:g10a.1c0i3d9it/yD0oNfJ01-2C4-4HK
could not mediate the reaction without addition of I2 (Table 1, bond promoting formation of the product via -elimination. By
9
b
entry 7). NaI showed a similar positive effect, while KBr could slightly tuning the reaction conditions, the cyclic ketones could
not promote the reaction (Table 1, entries 8 and 9). The also be could also be dehydrogenated. For instance, when
positive results perhaps are attributed to the different cyclohex-2-en-1-one was used, phenol was produced in 60%
1
1
inhibitory effects of KI on the Kornblum oxidation and - yield (2u). Cyclohexyl(phenyl)methanone was also transformed
elimination reaction of the key intermediate iodide enolates into benzophenone in 83% yield (2v). Heterocyclic ketones
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
(
see below). It is found that DMSO is essential to this reaction, were also applicable to this reaction, furnishing the expected
since no or only a trace amount of 2a could be detected in products in good yields (2w and 2x).
other solvents such as toluene, dioxane and DMF (Table 1,
a
Table 2. Iodine-Catalyzed ,-Dehydrogenation of Ketones and Aldehydes.
entries 10-12). When the reaction was carried out under air
atmosphere, the yield slightly decreased (Table 1, entry 13).
Finally, the reaction temperature was screened. Elevating the
o
reaction temperature (140 C) did not improve the reaction’s
o
efficiency, while lowering the temperature to 120 C lead to a
slight decrease of the yield (Table 1, entries 14 and 15).
a
Table 1. Iodine-Catalyzed ,-Dehydrogenation of 1,3-Diphenylpropan-1-one.
a
Reaction conditions: a mixture of 1,3-diphenylpropan-1-one 1a (0.1 mmol),
2.5 mol% I
2
, 10 mol% additive was heated in 1.5 mL solvent at the indicated
b
temperature for 16 h. GC yield using dihexyl as an internal standard.
c
d
o
e
o
under air atmosphere. 140 C. 120 C.
With the optimal reaction conditions in hand, the substrate
scope was subsequently investigated. As shown in Table 2,
both electron-rich and electron-deficient ketones underwent

,-dehydrogenation readily under the reaction conditions to
produce the corresponding conjugated enones in good to high
yields. Thus, in addition to 1a, derivatives with electron-
donating groups like methoxy and methyl at varied positions
on the benzene ring served well and were transformed into
the expected enones (2b-2f, 2i-2k, 2s and 2t). Halo groups (F
and Cl) survived well in the current catalytic system, facilitating
further derivatization of the products via cross coupling ( 2g, 2l-
2
n and 2t). Following the strategy, substrate bearing an
electron-withdrawing CF3 group was also dehydrogenated
readily (2o). The -extended and acetal-containing ketones
also proved to be good substrates for this reaction ( 2h, 2p and atmosphere. isolated yield. DMSO (2 mL). 140 C. 120 C. 10 mol% I2
a
Reaction conditions: a mixture of ketone 1 (0.2 mmol), 2.5 mol% I
2
, 10
o
mol% additive was heated in 3 mL DMSO at 130 C for 16 h under N
2
b
c
d
o
e
o
f
o
g
2
q). To our delight, exemplified by 2r, enones with three and 150 C. DMSO (1.5 mL).
2
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
Page 3 of 4
New Journal of Chemistry
Journal Name
Notably, in addition to ketones, aldehydes could also
undergo ,-dehydrogenation smoothly under the current oxidation more significantly, thus promotDiOngI: 1t0h.e10p39ro/Dd0uNcJt0io12n44oKf
reaction conditions to produce the corresponding conjugated 2a. When eqn 2 was performed in toluene, 1a was almost fully
enals. For example, cinnamaldehyde was produced in 76% recovered. The result indicated that DMSO might play an
isolated yield with the strategy (2y). Methoxy and chloro important role to activate molecular I2 in the iodination of 1a
COMMUNICATION
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
slowing down the reaction. However, KI inhibits tVhieewKAortircnlebOlnulimne
1
2
substituted enealdehydes were also generated in high yields forming 4a.
2z and 2aa). Being similar to ketones, cyclic aldehydes
exemplified by cyclohex-3-ene-1-carbaldehyde and
(
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
cyclohexanecarbaldehyde also worked well, furnishing the fully
dehydrogenated benzaldehyde in good yields (2ab). However,
probably due to the low acidity of -C-H bonds leading to
difficulty of the -elimination, aliphatic ketone was not
applicable to this reaction (2ac). When 4-phenylbutan-2-one
was used, no 2ad was detected. The result might be ascribed
to the competing oxidation of methyl group. Under the
reaction conditions, ester was also not applicable (2ae).
Practically, this reaction could be scaled up without any
decrease of reaction efficiency, well demonstrating its
synthetic value in organic synthesis. As shown in Scheme 2, In
the presence of 2.5 mol% I2 and 10 mol% KI, a mixture of 1a (1
Scheme 3. Control Experiments and Suitable Explanation.
On the basis of experiments described above and previous
works, a plausible mechanism was proposed and illustrated in
o
mmol) in 10 mL DMSO was heated at 130 C for 16 h. After
wash with water and evaporation in vacuum, the residue was
13
Scheme 4. Compound 1a firstly was iodinated by molecular I2
passed through
a SiO2 chromatographic column using
activated by DMSO to produce alpha iodide 4a, which
subsequently underwent -elimination to yield the expected
unsaturated product 2a. The HI concomitantly generated
during the reaction was re-oxidized to I2 by DMSO, completing
the catalytic cycle. KI might work through different inhibitory
petroleum ether/ethyl acetate (50:1) as an elute to afford the
analytically pure 2a in 73% isolated yield. When the reaction
was conducted at 5 mmol scales, 75% yield of 2a was also
obtained.
1
1
effects on the kornblum oxidation and -elimination reaction
of the key intermediate iodide enolates.
Scheme 2. Scale-Up Experiments for ,-Dehydrogenation.
To gain some mechanistic information, control experiments
were performed. It was found that the reaction still proceeded
smoothly in the presence of 2 equivalent BHT (2,6-di-tert-
butyl-4-methylphenol), indicating that this reaction might not
be a radical process (Scheme 3, eqn 1). After reaction of 1a, a
trace amount of tricarbonyl compound 3a was usually
detected in the reaction mixture by GC and GC-Ms. When the
reaction was carried out with 1 equivalent I2 under similar
reaction conditions, 52% yield of 3a and 40% yield of 2a was
generated (Scheme 3, eqn 2). By further addition of 4
Scheme 4. Proposed Mechanism for the Metal-Free Catalytic Dehydrogenation
of Ketones and Aldehydes.
equivlent KI, 2a was generated in 65% yield, while only a trace Conclusions
amount of 3a was detected. We also noticed that 17% 1a
In summary, we disclosed a facile I2/KI/DMSO system achieving
,-dehydrogantion of both ketones and aldehydes in one pot.
remained in the reaction (Scheme 3, eqn 3). By survey of

1
0
literatures, it was deduced that 3a would be generated
This reaction took place under a neutral condition and avoided
use of special strong oxidants and (or) transition metal
catalysts. A variety of conjugated enones and enals were
produced in good to high yields in the current catalytic system.
The gram-scale experiment also well demonstrated the
synthetic value of this new reaction.
1
1
through successive iodination and Kornblum oxidation
involving sequential formation of 4a, 5a and 6a. Meanwhile, it
is known that 4a could undergo -elimination to generate 2a.
Thus, it is reasonable that 4a was proposed as the key
intermediate for this reaction.-Elimination of 4a could
1
1
produce 2a, while Kornblum oxidation of 4a would lead to
final generation of by-product tricarbonyl compound 3a. The
Partial financial supports from HNNSF (Grant No.
2
19MS005), NSFC (Grant Nos: 21871070, 21573064), and the
Fundamental Research Funds for the Central Universities
Hunan University) are gratefully acknowledged.
1
1
addition of KI could inhibit both Kornblum oxidation and ,-
elimination reaction of the key intermediate alpha iodide 4a,
(
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 4 of 4
COMMUNICATION
Journal Name
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
(
h) A. Bhattacharya, L. M. DiMichele, U. H. DVoielwlinArgti,cleAO. nWline.
Conflicts of interest
There are no conflicts to declare.
Douglas and E. J. J. Grabowski, J. Am. Chem. Soc., 1988, 110,
DOI: 10.1039/D0NJ01244K
3318-3319.
7
(a) K. C. Nicolaou, Y. L. Zhong and P. S. Baran, J. Am. Chem.
Soc., 2000, 122, 7596-7597; (b) S. Dutta, S. S. Kotha and G.
Sekar, RSC Adv., 2015, 5, 47265-47269. (c) K. C. Nicolaou, T.
Montagnon and P. S. Baran, Angew. Chem. Int. Ed., 2002, 41,
993-996; (d) K. C. Nicolaou, D. L. F. Gray, T. Montagnon and S.
T. Harrison, Angew. Chem. Int. Ed., 2002, 41, 996-1000; (e) K.
C. Nicolaou, T. Montagnon, P. S. Baran and Y.- L. Zhong, J.
Am. Chem. Soc., 2002, 124, 2245-2258; (f) M. Uyanik, M.
Akakura and K. Ishihara, J. Am. Chem. Soc., 2009, 131, 251-
262.
(a) A. V. Iosub and S. S. Stahl, J. Am. Chem. Soc., 2015, 137,
3454-3457; (b) G. F. Pan, X. Q. Zhu, R. L. Guo, Y. R. Gao and Y.
Q. Wang, Adv. Synth. Catal., 2018, 360, 4774-4783; (c) T.
Diao, D. Pun and S. S. Stahl, J. Am. Chem. Soc., 2013, 135,
8205-8212; (d) T. Diao, T. J. Wadzinski and S. S. Stahl, Chem.
Sci., 2012, 3, 887-891.
(a) H. P. Kalmode, K. S. Vadagaonkar and A. C. Chaskar, RSC.
Adv., 2014, 4, 60316-60326; (b) Y. F. Liang, X. Li, X. Wang, M.
Zou, C. Tang, Y. Liang, S. Song and N. Jiao, J. Am. Chem. Soc.,
2016, 138, 12271-12277; (c) P. A. Sathe, K. S. Vadagaonkar,
M. V. Vhatkar, L. Melone and A. C. Chaskar, ChemistrySelect,
2018, 3, 277-283; (d) V. Sareen, V. Khatri, D. Shinde, S. Chugh
and S. Sareen, Heterocyclic Commun., 2010, 16, 33-34; (e) R.
Deshidi, S. Devari and B. A. Shah, Eur J. Org. Chem., 2015,
2015, 1428-1432; (f) R. Deshidi, M. Kumar, S. Devari and B. A.
Shah, Chem. Commun., 2014, 50, 9533-9535; (g) Y. P. Zhu, M.
Lian, F. C. Jia, M. C. Liu, J. J. Yuan, Q. H. Gao and A. X. Wu,
Chem. Commun., 2012, 48, 9086-9088; (h) M. Chennapuram,
N. R. Emmadi, C. Bingi and K. Atmakur, RSC Adv., 2015, 5,
19418-19425.
Notes and references
1
For selected examples, see: (a) A. W. Schuppe and T. R.
Newhouse, J. Am .Chem. Soc., 2017, 139, 631-634; (b) A. W.
Schuppe, D. Huang, Y. Chen and T. R. Newhouse, J. Am.
Chem. Soc., 2018, 140, 2062-2066; (c) K. Hung, X. Hu and T. J.
Maimone, Nat. Prod. Rep., 2018, 35, 174-202; (d) H.- L. Qin, J.
Leng, C.- P. Zhang, I. Jantan, M. W. Amjad, M. Sher, M.
Naeem-ul-Hassan, M. A. Hussain and S. N. A. Bukhari, J. Med.
Chem., 2016, 59, 3549-3561; (e) A. M. Rodríguez, R. D. Enriz,
L. N. Santagata, E. A. Jáuregui, M. J. Pestchanker and O. S.
Giordano, J. Med. Chem., 1997, 40, 1827-1834; (f) A. Ortiz, T.
Benkovics, G. L. Beutner, Z. Shi, M. Bultman, J. Nye, C.
Sfouggatakis and D. R. Kronenthal, Angew. Chem. Int. Ed.,
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
8
9
2
015, 54, 7185-7188; (g) R. A. Hill and A. Sutherland, Nat.
Prod. Rep., 2017, 34, 1180-1184; (h) M. Chen, A. J. Rago and
G. Dong, Angew. Chem. Int. Ed., 2018, 57, 16205-16209; (i) A.
W. Schuppe, Y. Zhao, Y. Liu and T. R. Newhouse, J. Am. Chem.
Soc., 2019, 141, 9191-9196.
2
(a) H. Cao, H. Jiang, H. Feng, J. M. C. Kwan, X. Liu and J. Wu, J.
Am. Chem. Soc., 2018, 140, 16360-16367; (b) J. Le Bras and J.
Muzart, Chem. Rev., 2011, 111, 1170-1214; (c) S. Otto and
JBFN. Engberts, Tetrahedron Lett., 1995, 36, 2645-2648; (d) T.
Yamazaki, N. Shinohara, T. Kitazume and S. Satot, J. Org.
Chem., 1995, 60, 8140-8141; (e) K. C. Nicolaou, S. A. Snyder,
T. Montagnon and G. Vassilikogiannakis, Angew. Chem. Int.
Ed., 2002, 41, 1668-1698; (f) G. Desimoni, G. Faita and P.
Quadrelli, Chem. Rev., 2018, 118, 2080-2248; (g) J. LeBras
and J. Muzart, Adv. Synth. Catal., 2018, 360, 2411-2428; (h) A. 10 (a) M. Liu, T. Chen, Y. Zhou and S. F. Yin, Catal. Sci. Technol.,
Sarkar, S. R. Roy and A. K. Chakraborti, Chem. Commun.,
011, 47, 4538-4540; (i) S. Mahato, S. Santra, R. Chatterjee,
G. V. Zyryanov, A. Hajra and A. Majee, Green Chem., 2017, 19,
282-3295.
(a) A. D. Abell and J. M. Taylor, J. Org. Chem., 1993, 58, 14-15;
b) J. E. Resek and A. I. Meyers, Tetrahedron Lett., 1995, 36,
7051-7054; (c) B. M. Trost, T. N. Salzmann and K. Hiroi, J. Am.
Chem. Soc., 1976, 98, 4887-4902; (d) K. B. Sharpless, R. F.
Lauer and A. Teranishi, J. Am. Chem. Soc., 1973, 95, 6137- 12 Under N2 atmosphere, no or trace product 2a was detected
2016, 15, 5792-5796; (b) M. L. N. Rao and D. N. Jadhav,
Tetrahedron Lett., 2006, 47, 6883-6886; (c) C. A. Horiuchi, S.-
J. Ji, M. Matsushita and W. Chai, Synthesis, 2004, 2, 202-204.
11 Kornblum oxidation involves a SN2 substitution process of
DMSO with alkyl halides, which would be inhibited by
addition of halide ions. For Kornblum oxidation, see: (a) N.
Kornblum, W. J. Jones and G. J. Anderson, J. Am. Chem. Soc.,
1959, 81, 4113-4114.
2
3
3
4
(
6
139; (e) H. J. Reich, I. L. Reich and J. M. Renga, J. Am. Chem.
when the reaction of 1a was performed in the absence of
DMSO, even though 1 equiv I2 was added, indicating that
DMSO was pivotal for this transformation. It was deduced
that DMSO could activate I2 by forming a molecular complex
DMSO.I2. See: M. C. Giordano, J. C. Bazán and A. J. Arvia, J.
Inorg. Nucl. Chem., 1966, 28, 1209-1214.
Soc., 1973, 95, 5813-5815; (f) H. J. Reich and Acc. Y, Chem.
Res., 1979, 12, 22-30; (g) S. S. Stahl and T. Diao, Compr. Org.
Synth., 2014, 7, 178-212.
(a) Y. Ito, T. Hirao and T. Saegusa, J. Org. Chem., 1978, 43,
1
011-1013; (b) Y. Lu, P. L. Nguyen, N. Lévaray and H. Lebel, J.
Org. Chem., 2013, 78, 776-779; (c) J.-Q. Yu, H.-C. Wu and E. J. 13 It is known I2 can react with KI to form KI3. The equilibrium
Corey, Org. Lett., 2005, 7, 1415-1417; (d) R. J. Theissen, J.
Org. Chem., 1971, 36, 752-757; (e) R. C. Larock, T. R.
Hightower, G. A. Kraus, P. Hahn and D. Zheng, Tetrahedron
Lett., 1995, 36, 2423-2426; (f) Y. Ito, H. Aoyama, T. Hirao, A.
Mochizuki and T. Saegusa, J. Am. Chem. Soc., 1979, 101, 494-
seems not to affect the reaction. We conducted two control
experiments on the ,-dehydrogenation of 1a: 1) by using
KI3/KI (2.5 mol % KI3 + 7.5 mol % KI, aqueous solution, 46 uL)
instead of I2/KI, 56% yield of 2a was obtained; 2) by adding
46 uL water under the standard reaction conditions, 59%
yield of 2a was obtained. See: (a) I. Lengyel, J. Li, K. Kustin
and I. R. Epstein, J. Am. Chem. Soc., 1996, 118, 3708-3719; (b)
G. Lente, J. Kalmár, Z. Baranyai, A. Kun, I. Kék, D. Bajusz, M.
Takács, L. Veres and I. Fábián, Inorg. Chem., 2009, 48, 1763-
1773; (c) E. A. Wappes, S. C. Fosu, T. C. Chopko and D. A.
Nagib, Angew. Chem. Int. Ed., 2016, 55, 9974-9978; (d) M.
Uyanik, T. Kato, N. Sahara, O. Katade and K. Ishihara, ACS
Catal. 2019, 9, 11619-11626.
4
96.
S. Astin, A. C. C. Newman and H. L. Riley, J. Chem. Soc., 1933,
91-394.
5
6
3
(a) Y. Liu, Y. Hu, Z. Cao, X. Zhan, W. Luo, Q. Liu and C. Guo,
Adv. Synth. Catal., 2019, 361, 1084-1091; (b) E. J. Agnello and
G. D. Laubach, J. Am. Chem. Soc., 1957, 79, 1257-1258; (c) A.
E. Greene, M.-J. Luche and J.-P. Deprés, J. Am. Chem. Soc.,
1
983, 105, 2435-2439; (d) D. Walker and J. D. Hiebert, Chem.
Rev., 1967, 67, 153-195; (e) R. J. Theissen, J. Org. Chem.,
1971, 36, 752-757; (f) A. O. King, R. K. Anderson, R. F.
Shuman, S. Karady, N. L. Abramson and A. W. Douglas, J. Org.
Chem., 1993, 58, 3384-3386; (g) K. B. Sharpless, R. F. Lauer
and A. Y. Teranishi, J. Am. Chem. Soc., 1973, 95, 6137-6139;
4
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins