Decarboxylative Borylation of mCPBA-Activated Aliphatic Acids

Article abstract of DOI:10.1021/acs.orglett.9b04218

A decarboxylative borylation of aliphatic acids for the synthesis of a variety of alkylboronates has been developed by mixing m-chloroperoxybenzoic acid (mCPBA)-activated fatty acids with bis(catecholato)diboron in N,N-dimethylformamide (DMF) at room temperature. A radical chain process is involved in the reaction which initiates from the B-B bond homolysis followed by the radical transfer from the boron atom to the carbon atom with subsequent decarboxylation and borylation.

Full text of DOI:10.1021/acs.orglett.9b04218

Letter
pubs.acs.org/OrgLett
Cite This: Org. Lett. XXXX, XXX, XXX−XXX
Decarboxylative Borylation of mCPBA-Activated Aliphatic Acids
Dian Wei, Tu-Ming Liu, Bo Zhou, and Bing Han*
State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou
730000, People’s Republic of China
S
* Supporting Information
ABSTRACT: A decarboxylative borylation of aliphatic acids
for the synthesis of a variety of alkylboronates has been
developed by mixing m-chloroperoxybenzoic acid (mCPBA)-
activated fatty acids with bis(catecholato)diboron in N,N-
dimethylformamide (DMF) at room temperature. A radical
chain process is involved in the reaction which initiates from
the B−B bond homolysis followed by the radical transfer from the boron atom to the carbon atom with subsequent
decarboxylation and borylation.
Scheme 1. Strategies for the Decarboxylative Borylation
oron-containing compounds are widely used in many
Bfields due to their unique charge distribution and strong
transformation ability.1 For example, organoboron derivatives
have proven to be a powerful coupling agent with the
advancement of Suzuki−Miyaura cross-coupling reaction in
the synthesis of pharmaceuticals and organic functional
materials.2 In addition, organic boronic acids and boronic
esters also exhibit certain biological activities because they have
enough electrophilicity of binding to amino acid residues.3
This brings new opportunities for discovery of boron-
containing drugs such as Velcade,4 Dutogliptin,5 and An-
2690.6 Given the importance of organic boron compounds,
their efficient synthesis has attracted more and more attention
from chemists. Traditionally, sensitive organolithium reagents7
and Grignard reagents8 are used to synthesize organoborons.
To expand the applicability of borylation, a number of
methods, including borylation of alkenes,9 transition-metal-
catalyzed borylation of organohalides,10 and activation of C−X
(X = H, C, N, O, F)11−15 bonds, have been developed.
Although these strategies have yielded good results, harsh and
complex reaction conditions are still required. With the further
advancement of chemistry, it is urgent to solve the problems of
energy and ecological environment brought about by chemical
agents.16
Carboxylic acid, an important biomass platform compound,
has attracted the attention of chemists because of its abundant
reserves, wide sources, and low toxicity.17 Therefore, the
synthesis of boron derivatives using carboxylic acid derivatives
has boomed.18 Recently, phenol-, amine-, and mercaptan-
activated carboxylic acids have been transformed into boronic
esters through transition-metal-catalyzed oxidative addition
and reductive elimination (Scheme 1a).12d−g With the
development of base-promoted and photoinduced methods
in radical borylation reaction, some novel protocols for radical
decarboxylative borylation have also been explored by using
phthalimide-activated carboxylic acids.19,20 Baran’s group first
realized nickel- or copper-catalyzed radical decarboxylative
borylation under strong alkaline conditions.21 The Lewis base-
catalyzed protocol was developed under metal-free thermal
conditions by Fu’s group.19g Li’s group finished this trans-
formation utilizing a photoredox strategy under mild
conditions.20f Glorius’20i and Aggarwal’s20a groups independ-
ently developed ingenious protocols to construct C−B bonds
by combining Lewis base activation with optical excitation. In
these reported reactions, transition metal, high temperature,
light irradiation, or long reaction time are ineluctable (Scheme
1b). Inspired by Aggarwal’s work, we envisioned that diacyl
peroxides might be used as a substitute of phthalimide esters to
Received: November 24, 2019
© XXXX American Chemical Society
A
DOI: 10.1021/acs.orglett.9b04218
Org. Lett. XXXX, XXX, XXX−XXX

Organic Letters
Letter
a
realize the borylation without extra light irradiation on account
of the motif of sustainable chemistry. Compared with stable
carboxylic phthalimide esters, peroxides exhibit relative low
stability and more activity since the BDE of the O−O bond in
peroxides (∼34 kcal/mol)22a is weaker than that of the N−O
bond in carboxylic phthalimide esters (∼55−65 kcal/mol).22b
Such properties of peroxides provide the possibility of the
reaction. In addition, although diacyl peroxides have been
widely used as a radical initiator, employing them as the alkyl
radical precursors in organic transformations is still unappre-
ciated.23 Herein, we wish to report a metal- and light-free
protocol for the radical decarboxylative borylation of diacyl
peroxides under ambient temperature using m-chloroperox-
ybenzoic acid (mCPBA) as the activator of carboxylic acids
(Scheme 1c). These diacyl peroxides could be easily accessed
from the condensation of a variety of carboxylic acids with
cheap and commercially available mCPBA. This protocol not
only represents a new and efficient mode for carboxylic acid
activation but also realizes the decarboxylative borylation of
carboxylic acids in a more rapid and convenient mode.
We initiated this study by stirring peroxide 1a (0.3 mmol)
and organodiboron compound 2 (0.39 mmol) in DMAc (1
mL) under argon atmosphere for 20 min. Then pinacol and
Et3N were charged, and the corresponding mixture was stirred
for an additional 1 h. No reaction took place when B2pin2 2a
and B2(OH)4 2b were used (Table 1, entries 1−2).
Encouragingly, when B2cat2 2c was used as the borating
reagent, the desired product 3a was acquired in 83% yield
(Table 1, entry 3). By screening solvents such as DMF,
CH3CN, dioxane, THF, HMPA, and DMPU, we found that
amides were specific solvents for an efficient transformation.
The yield of 3a was further increased to 89% in DMF, whereas
the reaction was inert in CH3CN, dioxane, and THF (Table 1,
entries 4−9). Increasing or decreasing the usage amount of 2c
did not gave better results (Table 1, entries 10 and 11). When
this transformation was carried out under air, the yield of 3a
was significantly reduced to 76%, suggesting that this reaction
is sensitive to air (Table 1, entry 12). In addition, the reaction
was immune to light since the yield of 3a was not affected
neither by blue LED irradiation nor in the dark (Table 1,
entries 13 and 14). Moreover, when symmetric diacyl peroxide
1a′ was tested in reaction, the desired product 3a could be
produced in 80% yield as well (Table 1, entry 15).
Unfortunately, 3a could not be produced when perester 1a″
was used in the protocol (Table 1, entry 16).
With the optimal conditions in hand, we investigated the
reaction applicability by treating a variety of activated aliphatic
acids with B2cat2. As shown in Scheme 2, primary acid
derivatives were first explored. Both linear and branched
aliphatic peroxyanhydrides were efficiently converted to the
expected primary alkylboronates 3b−d in 58−96% yields.
Peroxides containing alkenyl and alkynyl groups were also
compatible in the reaction, giving rise to the corresponding
products 3e and 3f in medium yields. 5-Chloro- and 5-
bromopentanoic acid derivatives transformed smoothly in the
protocol, delivering haloalkyl boronates 3g and 3h in 74% and
84% yields, respectively. Peroxide containing an ester group, as
in the case of 1i, also participated well in the reaction,
producing 3i in 54% yield. When aliphatic peroxides
incorporating aromatic rings such as phenyl and indole were
involved, the reaction gave the corresponding alkylboronates
3j−l in good yields. Notably, heptanediacid bisperoxide
reacted very well in the reaction, affording 1,5-bis(boronic
Table 1. Optimization of the Reaction Conditions
h
i
b
entry
substrate
B2(OR′)4
solvent
yield (%)
1
2
3
4
5
6
7
8
9
10
11
12
13
1a
1a
1a
1a
1a
1a
1a
1a
1a
1a
1a
1a
1a
1a
1a’
1a”
B2Pin2 (2a)
B2(OH)4 (2b)
B2cat2 (2c)
B2cat2 (2c)
B2cat2 (2c)
B2cat2 (2c)
B2cat2 (2c)
B2cat2 (2c)
B2cat2 (2c)
B2cat2 (2c)
B2cat2 (2c)
B2cat2 (2c)
B2cat2 (2c)
B2cat2 (2c)
B2cat2 (2c)
B2cat2 (2c)
DMAc
DMAc
DMAc
DMF
CH3CN
dioxane
THF
HMPA
DMPU
DMF
DMF
DMF
DMF
DMF
DMF
DMF
0
0
83
89
0
0
0
64
78
83
87
76
89
87
80
0
c
d
e
f
g
14
15
16
a
All reactions were carried out by stirring 1a (0.3 mmol) and 2 (1.3
equiv) in solvent (1 mL) under argon atmosphere at room
temperature for 20 min. Then pinacol (4 equiv) and Et3N (0.6
mL) were added, and the reaction mixture was stirred for an
additional 1 h, except as noted. Isolated yield. 2c (1.2 equiv) was
used. 2c (1.4 equiv) was used. The reaction was carried out under
air. The reaction was stirred in dark. The mixture was stirred under
blue LED irradiation. B2pin2 = bis(pinacolato)diboron. B2cat2
bis(catecholato)diboron. DMF = N,N-dimethylformamide. DMAc =
N,N-dimethylacetamide. THF = tetrahydrofuran. HMPA = hexam-
ethyl phosphoryl triamide. DMPU = 1,3-dimethyltetrahydropyrimi-
din-2(1H)-one.
b
c
d
e
f
g
h
=
i
ester) 3m in 59% yield. Next, the tolerance of secondary
aliphatic acid derivatives was tested. Cycloalkyl acid peroxides
encompassing cyclopropyl, cyclopentyl, cyclopentenyl, cyclo-
hexyl, indene, as well as bridged hydrocarbon were all suitable
for the decarboxylative borylation, yielding the desired
secondary alkylboronates 3n−t in good yields. It is noteworthy
that the present decarboxylative borylation provided excellent
stereoselectivity in the cases of 3n, 3s, and 3t where new
stereoisomeric centers were produced. Decarboxylative bor-
ylation of peroxides bearing the gem-difluoro group and pyran
ring proceeded very well, delivering 3u and 3v in moderate
yields. In addition, open-chain secondary acid derivative α-
methyl-hydrocinnamic acid peroxide was also a good candidate
in the present tactics, producing the open-chain secondary
alkylboronate 3w in 83% yield. Regrettably, when mCPBA-
activated 1-adamantanecarboxylic acid was subjected to the
standard conditions, the reaction failed to deliver alkylboronate
3x, probably because such a kind of mixed tertiary diacyl
peroxide was unstable. Instead, unlike primary and secondary
peresters, which were ineffective in the reaction, tertiary
peresters 1x transformed smoothly under standard conditions,
generating tertiary alkylboronate 3x in 51% yield. The
aforementioned decarboxylative borylation only exhibited the
regioselectivity on the aliphatic moiety of peroxides, which is
probably because aliphatic acids were easier to decarboxylate
than aryl acids. To see if this method is suitable for the
B
DOI: 10.1021/acs.orglett.9b04218
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Organic Letters
Letter
a b
,
To investigate the reaction mechanism, some control
experiments were conducted as shown in Scheme 3. The
Scheme 2. Scope of Aliphatic Peroxides
Scheme 3. Mechanistic Studies
blank experiment revealed that no reaction took place, and 1a
was almost quantitatively recovered when B2cat2 was absent
under the standard conditions (Scheme 3a). This result
suggests that the alkyl radical is generated by the reaction of
peroxide 1 with DMF-ligated B2cat2 rather than the
spontaneous decomposition of 1 itself. In addition, radical
clock experiments were performed as shown in Scheme 3b.
When 6-heptenoic acid derivative 1ad was carried out under
the standard reaction conditions, the direct radical decarbox-
ylative borylation product 3ad and the tandem cyclized
borylation product 3ad′ were obtained as a mixture in 75%
yield in a ratio of 2.75:1. When cyclopropylacetic acid peroxide
1ae was subjected to this reaction, ring-opening product 3e
was obtained in 30% yield as a sole product. These results
clearly demonstrate that a free radical process was involved in
the reaction by the treatment of 1 with 2c in DMF.
Based on the pertinent work of decarboxylative boryla-
tion19d,20a and our experimental results, it is assumed that a
radical chain process is involved in this transformation as
shown in Figure 1. The reaction is initiated by the thermal
homolysis of the B−B bond, which is caused by the reaction of
peroxide 1 and DMF-ligated B2cat2 A, providing DMF-
stabilized boron-center radical C and carbon-center radical
a
A mixture of 1 (0.3 mmol) and 2c (1.3 equiv) in DMF (1 mL) was
stirred for 20 min under argon atmosphere at room temperature.
Then pinacol (4 equiv) and Et3N (0.6 mL) were added, and the
reaction mixture was stirred for an additional 1 h, except as noted.
b
c
d
Isolated yield. 1a (1 mmol) was used. 1k (4 mmol, 1.52 g) was
e
used. B2cat2 (3 equiv), pinacol (8 equiv), and Et3N (1.2 mL) were
f
used. tert-Butyl-adamantane-1-carboperoxoate (0.3 mmol) was used.
g
tert-Butyl peroxybenzoate (0.3 mmol) or dibenzoyl peroxide (0.3
mmol) were used.
decarboxylative borylation of aromatic acids, the standard
conditions were applied to dibenzoyl peroxide (BPO) and tert-
butyl peroxybenzoate (TBPB). However, neither of them gave
the desired product 3y, probably because the decarboxylation
of the benzoic acid radical was a thermodynamic adverse
process. In order to further demonstrate the applicability of the
strategy, several natural carboxylic acid derivatives including
monounsaturated and polyunsaturated fatty acids as well as
lithocholic acid were investigated in the reaction. Conse-
quently, the corresponding alkylboronates 3z−ac were
generated in excellent yields. In addition, the reaction could
also be conducted on a gram scale without any difficulty, as in
the case of 3k, promising the practicability and application of
this protocol.
Figure 1. Proposed mechanism.
C
DOI: 10.1021/acs.orglett.9b04218
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Organic Letters
Letter
D. Then, the unstable intermediate D resolves into an alkyl
radical E with the release of CO2 and F. The low strength of
the O−O bond makes the radical propagation process more
favorable and spontaneous so that no additional energy supply
is required. Radical E is trapped by DMF-ligated B2cat2 A to
yield product G and radical C. The latter can also react with
peroxide 1 to yield alkyl radical E, CO2, and F to realize the
propagation of radical species. On the other hand, radical C
can be initiated by the thermal homolysis of bi-DMF-ligated
B2cat2 H as well. Finally, product 3 is produced by the
replacement of the catechol moiety in unstable compound G
by pinacol. On the other hand, a single electron transfer (SET)
might be involved for the tertiary perester (see Supporting
Information).
With the preliminary cognition of reaction mechanism, we
tried to construct C−C bonds by utilizing the generated alkyl
radical in this protocol. It was gratifying to detect that
quinones 4 such as vitamin K3 4a and 2-chloro-1,4-
naphthoquinone 4b could be used in the protocol to produce
the desired C−C bond-forming products 5a and 5b in
moderate yields (Scheme 4). Apparently, this method
possesses the potential to construct C−C bonds under mild
conditions besides C−B bonds.
ACKNOWLEDGMENTS
■
We thank the National Natural Science Foundation of China
(Nos. 21873041, 21632001, and 21422205), the Fundamental
Research Funds for the Central Universities (Nos. lzujbky-
2016-ct02 and lzujbky-2016-ct08), Program for the Changjiang
Scholars and Innovative Research Team in University (IRT-
15R28), and the “111” Project for financial support.
REFERENCES
■
(1) (a) Miyaura, N. Top. Curr. Chem. 2002, 219, 11−59. (b) Kotha,
S.; Lahiri, K.; Kashinath, D. Tetrahedron 2002, 58, 9633−9640.
(2) (a) Suzuki, A. Angew. Chem., Int. Ed. 2011, 50, 6722−6737.
(b) Magano, J.; Dunetz, J. R. Chem. Rev. 2011, 111, 2177−2250.
(3) Hunter, P. EMBO Rep. 2009, 10, 125−128.
(4) (a) Hideshima, T.; Richardson, P.; Chauhan, D.; Palombella, V.
J.; Elliott, P. J.; Adams, J.; Anderson, K. C. Cancer Res. 2001, 61,
3071−3076. (b) Paramore, A.; Frantz, S. Nat. Rev. Drug Discovery
2003, 2, 611−612.
(5) Pattzi, H. M. R.; Pitale, S.; Alpizar, M.; Bennett, C.; O’Farrell, A.
M.; Li, J.; Cherrington, J. M.; Guler, H.-P. PHX1149-PROT202 Study
Group. Diabetes, Obes. Metab. 2010, 12, 348−355.
(6) Baker, S. J.; Zhang, Y. K.; Akama, T.; Lau, A.; Zhou, H.;
Hernandez, V.; Mao, W.; Alley, M. R.; Sanders, V.; Plattner, J. J. J.
Med. Chem. 2006, 49, 4447−4450.
(7) Andreas, M. Eur. Pat. Appl. EP1236730 (A2), 2001.
(8) Kabalka, G. W.; Sastry, U.; Sastry, K. A. R.; et al. J. Organomet.
Chem. 1983, 259, 269−274.
a b
,
Scheme 4. C−C Bond Formation
(9) For selected recent works of hydroboration of alkenes reactions,
see: (a) Lee, K. S.; Zhugralin, A. R.; Hoveyda, A. H. J. Am. Chem. Soc.
2009, 131, 7253−7255. (b) Schiffner, J. A.; Muther, K.; Oestreich, M.
̈
Angew. Chem., Int. Ed. 2010, 49, 1194−1196. (c) Logan, K. M.;
Sardini, S. R.; White, S. D.; Brown, M. K. J. Am. Chem. Soc. 2018, 140,
159−162. (d) Liu, Z.; Ni, H.−Q.; Zeng, T.; Engle, K. M. J. Am. Chem.
Soc. 2018, 140, 3223−3227.
a
Reaction conditions: the mixture of 1d (0.9 mmol), 4 (0.3 mmol),
and 2c (0.6 mmol) in DMF (1 mL) was stirred for 20 h at room
(10) For selected recent works of transition-metal-catalyzed cross-
couplings of organohalides with diborons, see: (a) Ishiyama, T.;
Murata, M.; Miyaura, N. J. Org. Chem. 1995, 60, 7508−7510.
(b) Ishiyama, T.; Itoh, Y.; Kitano, T.; Miyaura, N. Tetrahedron Lett.
1997, 38, 3447−3450. (c) Takagi, J.; Takahashi, K.; Ishiyama, T.;
Miyaura, N. J. Am. Chem. Soc. 2002, 124, 8001−8006. (d) Billingsley,
K. L.; Barder, T. E.; Buchwald, S. L. Angew. Chem., Int. Ed. 2007, 46,
5359−5363. (e) Molander, G. A.; Trice, S. L. J.; Dreher, S. D. J. Am.
b
temperature under an argon atmosphere. Isolated yield.
In conclusion, a new approach for decarboxylative borylation
has been developed by the treatment of mCPBA-activated fatty
acids with B2cat2. This strategy provides effective and handy
access for the synthesis of a variety of alkylboronates without
the need for metal, additive, and illumination. In addition, this
strategy can also be applied to the forging of C−C bonds. For
details of mechanism and applications of this reaction, further
in-depth studies are being conducted.
́
Chem. Soc. 2010, 132, 17701−17703. (f) Diner, C.; Szabo, K. J. J. Am.
Chem. Soc. 2017, 139, 976−984.
(11) For selected recent works of transition-metal-catalyzed C−H
borylation reactions, see: (a) Mkhalid, I. A. I.; Barnard, J. H.; Marder,
T. B.; Murphy, J. M.; Hartwig, J. F. Chem. Rev. 2010, 110, 890−931.
(b) Hartwig, J. F. Acc. Chem. Res. 2012, 45, 864−873. (c) Xu, L.;
Wang, G.; Zhang, S.; Wang, H.; Wang, L.; Liu, L.; Jiao, J.; Li, P.
Tetrahedron 2017, 73, 7123−7157. (d) Zou, X.; Zhao, H.; Li, Y.; Gao,
Q.; Ke, Z.; Xu, S. J. Am. Chem. Soc. 2019, 141, 5334−5342.
(e) Fukuda, K.; Iwasawa, N.; Takaya, J. Angew. Chem., Int. Ed. 2019,
58, 2850−2853. (f) Mihai, M. T.; Davis, H. J.; Genov, G. R.; Phipps,
R. J. ACS Catal. 2018, 8, 3764−3769. (g) Xue, C.; Luo, Y.; Teng, H.;
Ma, Y.; Nishiura, M.; Hou, Z. ACS Catal. 2018, 8, 5017−5022.
(h) Bisht, R.; Hoque, M. E.; Chattopadhyay, B. Angew. Chem., Int. Ed.
2018, 57, 15762−15766. (i) Mfuh, A. M.; Nguyen, V. T.; Chhetri, B.;
Burch, J. E.; Doyle, J. D.; Nesterov, V. N.; Arman, H. D.; Larionov, O.
V. J. Am. Chem. Soc. 2016, 138, 8408−8411.
ASSOCIATED CONTENT
■
S
* Supporting Information
The Supporting Information is available free of charge at
https://pubs.acs.org/doi/10.1021/acs.orglett.9b04218.
Experimental details and copies of spectra (PDF)
AUTHOR INFORMATION
■
Corresponding Author
*E-mail: hanb@lzu.edu.cn.
ORCID
(12) For selected recent works of transition-metal-catalyzed C−C
borylation reactions, see: (a) Tobisu, M.; Kinuta, H.; Kita, Y.;
́
Remond, E.; Chatani, N. J. Am. Chem. Soc. 2012, 134, 115−118.
(b) Tobisu, M.; Kita, Y.; Chatani, N. J. Am. Chem. Soc. 2006, 128,
8152−8153. (c) Tobisu, M.; Kita, Y.; Ano, Y.; Chatani, N. J. Am.
Chem. Soc. 2008, 130, 15982−15989. (d) Ochiai, H.; Uetake, Y.;
Niwa, T.; Hosoya, T. Angew. Chem., Int. Ed. 2017, 56, 2482−2486.
(e) Hu, J.; Zhao, Y.; Liu, J.; Zhang, Y.; Shi, Z. Angew. Chem., Int. Ed.
2016, 55, 8718−8722. (f) Guo, L.; Rueping, M. Chem. - Eur. J. 2016,
Bo Zhou: 0000-0002-8713-5906
Bing Han: 0000-0003-0507-9742
Notes
The authors declare no competing financial interest.
D
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Org. Lett. XXXX, XXX, XXX−XXX

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Letter
22, 16787−16790. (g) Pu, X.; Hu, J.; Zhao, Y.; Shi, Z. ACS Catal.
2016, 6, 6692−6698. (h) Dai, P.−F.; Ning, X.−S.; Wang, H.; Cui,
X.−C.; Liu, J.; Qu, J.−P.; Kang, Y. Angew. Chem., Int. Ed. 2019, 58,
5392−5395.
(13) For selected recent works of transition-metal-catalyzed C−N
borylation reactions, see: (a) Tobisu, M.; Nakamura, K.; Chatani, N.
J. Am. Chem. Soc. 2014, 136, 5587−5590. (b) Zhang, H.; Hagihara, S.;
Itami, K. Chem. - Eur. J. 2015, 21, 16796−16800. (c) Basch, C. H.;
Cobb, K. M.; Watson, M. P. Org. Lett. 2016, 18, 136−139. (d) Hu, J.;
Sun, H.; Cai, W.; Pu, X.; Zhang, Y.; Shi, Z. J. Org. Chem. 2016, 81,
14−24. (e) Hu, J.; Wang, G.; Li, S.; Shi, Z. Angew. Chem., Int. Ed.
2018, 57, 15227−15231. (f) Mo, F.; Jiang, Y.; Qiu, D.; Zhang, Y.;
Wang, J. Angew. Chem., Int. Ed. 2010, 49, 1846−1849.
(14) For selected recent works of transition-metal-catalyzed C−O
borylation reactions, see: (a) Huang, K.; Yu, D.−G.; Zheng, S.−F.;
Wu, Z.−H.; Shi, Z.−J. Chem. - Eur. J. 2011, 17, 786−791. (b) Kinuta,
H.; Tobisu, M.; Chatani, N. J. Am. Chem. Soc. 2015, 137, 1593−1600.
(15) For selected recent works of transition-metal-catalyzed C−F
borylation reactions, see: (a) Zhou, J.; Kuntze-Fechner, M. W.;
Bertermann, R.; Paul, U. S. D.; Berthel, J. H. J.; Friedrich, A.; Du, Z.;
Marder, T. B.; Radius, U. J. Am. Chem. Soc. 2016, 138, 5250−5253.
(b) Liu, X.−W.; Echavarren, J.; Zarate, C.; Martin, R. J. Am. Chem.
Soc. 2015, 137, 12470−12473. (c) Niwa, T.; Ochiai, H.; Watanabe,
Y.; Hosoya, T. J. Am. Chem. Soc. 2015, 137, 14313−14318. (d) Guo,
W.−H.; Min, Q.−Q.; Gu, J.−W.; Zhang, X. Angew. Chem., Int. Ed.
2015, 54, 9075−9078. (e) Bose, S. K.; Deißenberger, A.; Eichhorn,
A.; Steel, P. G.; Lin, Z.; Marder, T. B. Angew. Chem., Int. Ed. 2015, 54,
11843−11847. (f) Mfuh, A. M.; Doyle, J. D.; Chhetri, B.; Arman, H.
D.; Larionov, O. V. J. Am. Chem. Soc. 2016, 138, 2985−2988.
(g) Mfuh, A. M.; Schneider, B. D.; Cruces, W.; Larionov, O. V. Nat.
Protoc. 2017, 12, 604−610. (h) Tian, Y.-M.; Guo, X.-N.; Kuntze-
Fechner, M. W.; Krummenacher, I.; Braunschweig, H.; Radius, U.;
Steffen, A.; Marder, T. B. J. Am. Chem. Soc. 2018, 140, 17612−17623.
(16) (a) Clark, J. H. Green Chem. 1999, 1, 1−8. (b) Anastas, P. T.;
Warner, J. C. Green Chemistry: Theory and Practice; Oxford University
Press, 1998.
2018, 57, 15430−15434. (f) Hu, D.; Wang, L.; Li, P. Org. Lett. 2017,
19, 2770−2773. (g) Chen, K.; Zhang, S.; He, P.; Li, P. Chem. Sci.
2016, 7, 3676−3680. (h) Chen, K.; Cheung, M. S.; Lin, Z. Y.; Li, P.
Org. Chem. Front. 2016, 3, 875−879. (i) Candish, L.; Teders, M.;
Glorius, F. J. Am. Chem. Soc. 2017, 139, 7440−7443. (j) Sandfort, F.;
Strieth-Kalthoff, F.; Klauck, F. J. R.; James, M. J.; Glorius, F. Chem. -
Eur. J. 2018, 24, 17210−17214. (k) Cheng, Y.; Muck-Lichtenfeld, C.;
̈
Studer, A. J. Am. Chem. Soc. 2018, 140, 6221−6225. (l) Cheng, Y.;
Muck-Lichtenfeld, C.; Studer, A. Angew. Chem., Int. Ed. 2018, 57,
16832−16836. (m) Friese, F. W.; Studer, A. Angew. Chem., Int. Ed.
2019, 58, 9561−9564. (n) Zhang, J.−J.; Duan, X.−H.; Wu, Y.; Yang,
J.−C.; Guo, L.−N. Chem. Sci. 2019, 10, 161−166. (o) Liu, W.; Yang,
X.; Gao, Y.; Li, C. J. J. Am. Chem. Soc. 2017, 139, 8621−8627.
(p) Zhou, N.; Yuan, X.-A.; Zhao, Y.; Xie, J.; Zhu, C. Angew. Chem., Int.
Ed. 2018, 57, 3990−3994. (q) Zhang, L.; Jiao, L. J. Am. Chem. Soc.
2019, 141, 9124−9128. (r) Zhang, L.; Jiao, L. J. Am. Chem. Soc. 2019,
141, 9124−9128. (s) Mazzarella, D.; Magagnano, G.; Schweitzer-
Chaput, B.; Melchiorre, P. ACS Catal. 2019, 9, 5876−5880.
(21) (a) Li, C.; Wang, J.; Barton, L. M.; Yu, S.; Tian, M.; Peters, D.
S.; Kumar, M.; Yu, A. W.; Johnson, K. A.; Chatterjee, A. K.; Yan, M.;
Baran, P. S. Science 2017, 356, No. eaam7355. (b) Wang, J.; Shang,
M.; Lundberg, H.; Feu, K. S.; Hecker, S. J.; Qin, T.; Blackmond, D.
G.; Baran, P. S. ACS Catal. 2018, 8, 9537−9542.
(22) (a) Luo, Y.-R. Handbook of Bond Dissociation Energies in
Organic Compounds; CRC Press: Boca Raton, 2003. (b) Cremer, D.
The Chemistry of Peroxides; Patai, S., Ed.; Wiley: Chichester, 1983.
(23) Representative works on generation of alkyl radical by using
diacyl peroxide: (a) Jian, W.; Ge, L.; Jiao, Y.; Qian, B.; Bao, H. Angew.
Chem., Int. Ed. 2017, 56, 3650−3654. (b) Qian, B.; Chen, S.; Wang,
T.; Zhang, X.; Bao, H. J. Am. Chem. Soc. 2017, 139, 13076−13082.
(c) Zhu, N.; Zhao, J.; Bao, H. Chem. Sci. 2017, 8, 2081−2085.
(d) Zhu, X.; Deng, W.; Chiou, M.-F.; Ye, C.; Jian, W.; Zeng, Y.; Jiao,
Y.; Ge, L.; Li, Y.; Zhang, X.; Bao, H. J. Am. Chem. Soc. 2019, 141,
548−559. (e) Rueda-Becerril, M.; Chatalova Sazepin, C.; Leung, J. C.
T.; Okbinoglu, T.; Kennepohl, P.; Paquin, J.-F.; Sammis, G. M. J. Am.
Chem. Soc. 2012, 134, 4026−4029. (f) Ryzhkov, L. R. J. Org. Chem.
1996, 61, 2801−2808.
(17) (a) Holladay, J. E.; Bozell, J. J.; White, J. F.; Johnson, D. Top
Value Added Chemicals from Biomass. Vol. II: Results of Screening for
Potential Candidates from Biorefinery Lignin; PNNL and University of
the Tennessee, 2007. (b) Bozell, J. J.; Petersen, G. R. Green Chem.
2010, 12, 539−554.
(18) Xu, L. Eur. J. Org. Chem. 2018, 2018, 3884−3890.
(19) For selected recent works of base-promoted radical borylation
reaction, see: (a) Roberts, B. P. Chem. Soc. Rev. 1999, 28, 25−35.
(b) Curran, D. P.; Solovyev, A.; Makhlouf Brahmi, M.; Fensterbank,
L.; Malacria, M.; Lacote, E. Angew. Chem., Int. Ed. 2011, 50, 10294−
10317. (c) Shimoi, M.; Maeda, K.; Geib, S. J.; Curran, D. P.;
Taniguchi, T. Angew. Chem., Int. Ed. 2019, 58, 6357−6361. (d) Wang,
G.; Zhang, H.; Zhao, J.; Li, W.; Cao, J.; Zhu, C.; Li, S. Angew. Chem.,
Int. Ed. 2016, 55, 5985−5989. (e) Wang, G.; Cao, J.; Gao, L.; Chen,
W.; Huang, W.; Cheng, X.; Li, S. J. Am. Chem. Soc. 2017, 139, 3904−
3910. (f) Zhang, L.; Jiao, L. J. Am. Chem. Soc. 2017, 139, 607−610.
(g) Zhang, L.; Jiao, L. Chem. Sci. 2018, 9, 2711−2722. (h) Cheng, W.
M.; Shang, R.; Zhao, B.; Xing, W. L.; Fu, Y. Org. Lett. 2017, 19,
4291−4294. (i) Kischkewitz, M.; Okamoto, K.; Muck-Lichtenfeld, C.;
̈
Studer, A. Science 2017, 355, 936−938. (j) Hu, J.; Wang, G.; Li, S.;
Shi, Z. Angew. Chem., Int. Ed. 2018, 57, 15227−15231. (k) Ren, S. C.;
Zhang, F. L.; Qi, J.; Huang, Y. S.; Xu, A. Q.; Yan, H. Y.; Wang, Y. F. J.
Am. Chem. Soc. 2017, 139, 6050−6053. (l) Ren, S. C.; Zhang, F. L.;
Xu, A. Q.; Yang, Y.; Zheng, M.; Zhou, X.; Fu, Y.; Wang, Y. F. Nat.
Commun. 2019, 10, 1934.
(20) For selected recent works of photoinduced radical borylation
reaction, see: (a) Fawcett, A.; Pradeilles, J.; Wang, Y.; Mutsuga, T.;
Myers, E. L.; Aggarwal, V. K. Science 2017, 357, 283−286. (b) Wu, J.;
He, L.; Noble, A.; Aggarwal, V. K. J. Am. Chem. Soc. 2018, 140,
10700−10704. (c) Silvi, M.; Aggarwal, V. K. J. Am. Chem. Soc. 2019,
141, 9511−9515. (d) Silvi, M.; Sandford, C.; Aggarwal, V. K. J. Am.
Chem. Soc. 2017, 139, 5736−5739. (e) Shu, C.; Mega, R. S.;
Andreassen, B. J.; Noble, A.; Aggarwal, V. K. Angew. Chem., Int. Ed.
E
DOI: 10.1021/acs.orglett.9b04218
Org. Lett. XXXX, XXX, XXX−XXX