Photoinduced selective hydrophosphinylation of allylic compounds with diphenylphosphine oxide leading to γ-functionalized P-ligand precursors

Article abstract of DOI:10.1007/s11164-021-04433-7

A series of bifunctional phosphine compounds promising as γ-functionalized phosphine ligand precursors are conveniently synthesized by the radical addition of diphenylphosphine oxide (Ph₂P(O)H) to allylic compounds under photoirradiation. The p

Full text of DOI:10.1007/s11164-021-04433-7

Research on Chemical Intermediates
https://doi.org/10.1007/s11164-021-04433-7
Photoinduced selective hydrophosphinylation of allylic
compounds with diphenylphosphine oxide leading
to γ‑functionalized P‑ligand precursors
Dat Phuc Tran1 · Yuki Sato1 · Yuki Yamamoto1 · Shin‑ichi Kawaguchi2 ·
Shintaro Kodama1 · Akihiro Nomoto1 · Akiya Ogawa1
Received: 19 November 2020 / Accepted: 4 March 2021
© The Author(s), under exclusive licence to Springer Nature B.V. 2021
Abstract
A series of bifunctional phosphine compounds promising as γ-functionalized phos-
phine ligand precursors are conveniently synthesized by the radical addition of
diphenylphosphine oxide (Ph2P(O)H) to allylic compounds under photoirradiation.
The photoinduced addition proceeds regioselectively in an anti-Markovnikov man-
ner, and phosphines having hydroxy, alkoxy, aryloxy, acyloxy, and thio groups at
the γ-position can be prepared by simple operation. Interestingly, novel continuous
addition of Ph2P(O)H to two molecules of allylic ethers and related compounds is
also observed, although their yields are moderate. The substituent and steric efects
of the allylic substituents on the radical addition are discussed in detail.
Keywords Diphenylphosphine oxide · Allylic compound · Radical addition · Anti-
Markovnikov addition · Continuous addition
Introduction
Organophosphorus compounds are widely used in catalytic technologies, materials,
and pharmaceuticals, so the methods of forming of C–P bonds have received a great
deal of attention [1–5]. One of the simplest synthetic methods for C–P bond formation
*
*
*
Shin-ichi Kawaguchi
skawa@cc.saga-u.ac.jp
Shintaro Kodama
skodama@chem.osakafu-u.ac.jp
Akiya Ogawa
ogawa@chem.osakafu-u.ac.jp
1
2
Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture
University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka 599-8531, Japan
Center for Education and Research in Agricultural Innovation, Faculty of Agriculture, Saga
University, 152-1 Shonan-cho, Karatsu, Saga 847-0021, Japan
Vol.:(0123456789)
1 3

D. P. Tran et al.
Scheme 1 Photoinduced addition of Ph2P(O)H to alkenes
Scheme 2 Photoinduced hydrophosphinylation of allyl phenyl ether with diphenylphosphine oxide
[2–31] is the addition of the secondary phosphine oxides to alkenes [32, 33] due to
the low bond dissociation energy (BDEs) of P–H bonds [34]. The mechanism of these
reactions has been reported to include radical and/or ionic intermediates [35–40].
In our previous work, we reported the anti-Markovnikov addition of Ar2P(O)–H to
unsaturated bonds [41, 42]. Photoirradiation produces a phosphinoyl radical, which
attacks the terminal carbon of alkene [41, 42] to generate a carbon-centered radical.
Subsequent hydrogen abstraction from diphenylphosphine oxide yields a hydrophos-
phinylated product (Scheme 1).
This hydrophosphinylation is very advantageous, because this metal-free method
proceeds using no solvent and additives such as base and acid with simple operation.
If the photoinduced hydrophosphinylation is applied to allylic heteroatom compounds,
a series of 1,3-bidentate phosphorus ligand precursors can conveniently be synthesized
(Eq. 1).
We here report a metal-free photoinduced hydrophosphinylation of a series of allylic
compounds with diphenylphosphine oxide leading to γ-heteroatom-functionalized
phosphine oxides as 1,3-bidentate P-ligand precursors.
Furthermore, when allyl phenyl ether is used for the photoinduced hydrophosphi-
nylation, interestingly, in addition to the desired hydrophosphinylation product (56%
yield), namely [P]-monomer, a duplicate addition product, namely [P]-dimer, is also
formed in 28% yield (Scheme 2).
1 3

Photoinduced selective hydrophosphinylation of allylic…
This paper also deals with the insight into the mechanism for the formation of
[P]-dimer.
Results and discussion
Hydrophosphinylation of alkenes with diarylphosphine oxides is one of the most
straightforward methods for introducing phosphorus units into organic mole-
cules, because the addition reactions using air- and moisture-stable pentavalent
phosphorus reagents are highly atom-economical by avoiding troublesome treat-
ments of unstable phosphorus reagents [32, 33]. The hydrophosphinylation can
proceed via ionic, radical, and transition-metal-catalyzed processes. For ionic
hydrophosphinylation, acid- or base-catalyzed addition of Ar2P(O)H to electron-
defcient alkenes is frequently reported to proceed via a conjugate addition to
α,β-unsaturated carbonyl and cyano compounds [43–46]. The transition-metal-
catalyzed hydrophosphinylation is a powerful method for the synthesis of phos-
phorus compounds, because the regio- and stereoselectivity can be controlled by
the selection of catalysts and reaction conditions [47–61]. The radical hydrophos-
phinylation can be induced by the addition of radical initiators or upon photoir-
radiation, and it selectively afords anti-Markovnikov adducts [62–66]. Notably,
metal-free and additive-free procedures using the radical hydrophosphinylation
are much advantageous in view of environmental conservation. In the present
photoinduced hydrophosphinylation of allylic compounds, simple operations such
as photoirradiation in the absence of solvent have been successfully achieved.
When a mixture of diphenylphosphine oxide 1a (0.20 mmol) and allyl alcohol
2a (1.00 mmol) in a NMR tube (Pyrex) was irradiated with a Xe lamp (500 W)
at room temperature for 18 h, the desired diphenyl(3-hydroxypropyl)phosphine
oxide 3aa was successfully obtained in 88% yield (Table 1, entry 1). Similarly,
allyl methyl ether 2b underwent regioselective hydrophosphinylation to aford
diphenyl(3-methoxypropyl)phosphine oxide 3ab in 82% yield (entry 2). In the
case of allyl phenyl ether 2c, the corresponding hydrophosphinylation product
3ac was formed in 56% yield, and interestingly, the duplicate addition of 1a to
two molecules of 2c took place to give 4ac in 28% yield (entry 3). Allyl acetate
2d also exhibited a similar product selectivity, namely single adduct 3ad and
double adduct 4ad were obtained in 55% and 27% yields, respectively (entry 4).
The hydrophosphinylation of allyl aryl ethers 2e and 2f was tolerant the electron-
donating and electron-withdrawing groups (entries 5 and 6), and single adducts
3ae and 3af were formed as the major product along with double adducts 4ae and
4af as minor products. In contrast, allyl methyl sulfde 2g exclusively aforded
single adduct 3ag in good yield without formation of double adduct 4ag (entry
7). In the case of allyl phenyl sulfde 2h, adducts 3ah and 4ah were generated
in 14% and 10% yields, respectively (entry 8). On the other hand, allyl phenyl
selenide 2i did not aford the corresponding adducts 3ai and 4ai (entry 9). As PhS
and PhSe groups are good leaving groups, the photoinduced reaction of 1a with
2h and 2i might proceed via the elimination of PhS• and PhSe• to provide allyl
phosphine oxide and related compounds (Scheme 3).
1 3

D. P. Tran et al.
Table 1 Photoinduced hydrophosphinylation of allylic compounds
In the case of allylbenzene 2j, adduct 3aj was formed in 73% yield, but
there was no adduct 4aj (entry 10). The reactions of vinyl compounds such as
cyclohexyl vinyl ether 2k with 1a aforded 92% yield of 3ak along with small
amount of 4ak (entry 11). It was also acceptable to use a super-high pressure Hg
lamp as the light source, and the photoinduced addition of 1a to 2k aforded 3ak
1 3

Photoinduced selective hydrophosphinylation of allylic…
Scheme 3 Photoinduced substitution reaction between allyl phenyl chalcogenides and Ph2P(O)H
and 4ak in 84% and 16% yields, respectively (entry 12). Homoallyl phenyl ether
2l provided 3al and 4al in 78% and 13% yields, respectively (entry 13). Homoal-
lyl phenyl sulfde 2m was allowed to react with 1a to give only adduct 3am in
80% yield (entry 14).
As can be seen from Table 1, the photoinduced hydrophosphinylation of allylic
and related compounds successfully provided a series of 1,3-bidentate P-ligand
precursors, which can easily be converted to the corresponding trivalent phosphine
ligands by the reduction with DIBAL-H [67]1.
In particular, it has been found that allylic compounds bearing an oxygen atom at
the allylic position aford duplicate addition products 4 as byproducts. To get insight
into the formation of multiple addition products, the reaction of diphenylphos-
phine oxide 1a with allyl phenyl ether 2c was carried out varying the amounts of 2c
(Table 2).
As shown in Table 2, the reaction of 1a with 1 equiv. of 2c aforded [P]-monomer
(3ac), [P]-dimer (4ac), and [P]-polymers (5ac) in 67%, 6%, and 15% yields, respec-
tively (entry 1). When the amounts of 2c increased to 3 equiv., the yields of 3ac and
5ac decreased to 59% and 5%, respectively and the yield of 4ac increased to 29%
(entry 2). The photoirradiated reactions of 1a with 5 equiv. of 2c using a high-pres-
sure mercury lamp or a xenon lamp gave the similar results (entries 3 and 4). When
the reactions were conducted in 10 or 15 equiv. of 2c, the yields of both 3ac and 4ac
decreased and the yield of 5ac increased to 18% (entries 5–6). These results indicate
that the use of large amounts of allylic compounds resulted in decrease in the forma-
tion of [P]-monomer.
We next evaluated the infuence of P–H compounds on the single/multiple addi-
tion using 5 equiv. of 2c (Table 3).
The addition of diphenylphosphine (Ph2PH, 1b) and diphenylphosphine sulfde
(Ph2P(S)H, 1c) to allyl phenyl ether 2c produced only [P]-monomers 3bc and 3cc
in 62% and 89% yields, respectively (entries 2–3). In both cases, [P]-dimers 4bc
and 4cc were not produced under the condition. In the case of 1b, the less bulkiness
around the phosphorus group might accelerate the hydrogen abstraction of the gen-
erated carbon radical from 1b. The bond dissociation energy (BDE) [34] of the P–H
bonds of 1c is lower than that of 1a successfully improved the product selectivity to
1
Upon treating with DIBAL-H, γ-functionalized P-ligand precursors, Ph2P(O)–CH2CH2CH2–X, (X =
functional group), can be converted to the corresponding phosphines, Ph2P–CH2CH2CH2–X, which are
allowed to complex with Me2S•BH3, followed by purifcation of thus formed Ph2P(BH3)–CH2CH2CH2–
X by column chromatography. Then, deprotection using DABCO successfully afords γ-functionalized
P-ligands, Ph2P–CH2CH2CH2–X.
1 3

D. P. Tran et al.
Table 2 Infuence of amounts of allyl ether 2c on the formation of duplicate and multiplicate addition
products 4ac and 5ac
Entry
Amounts of 2c
Yielda (%)
3ac
4ac
5ac
1c
2c
3c
4
5
6
1 equiv.
3 equiv.
5 equiv.
5 equiv.
10 equiv.
15 equiv.
67
59
58
56
45
35
6
15
5
5
4
18
29
33
28
21
16
18
aDetermined by 1H NMR. bn≥3
cHigh-pressure Hg lamp, 25 h
Table 3 Single/multiple addition using several P–H compounds
Entry
P source
Yielda (%)
3
4
1
2
3
4
Ph2P(O)H, 1a
3ac, 56%
3bc, 62%
3cc, 89%
3dc, 96%
3ec, 36%
3fc, 44%
3gc 0%
4ac, 28%
4bc 0%
4cc, 0%
4dc, 4%
4ec, 27%
4fc, 9%
4gc 0%
Ph2PH, 1b
Ph2P(S)H, 1c
Ph2P(Se)H, 1d
(p-MeOC6H4)2P(O)H, 1e
(p-FC6H4)2P(O)H, 1f
(EtO)2P(O)H, 1g
5b
6b
7b
Bold values represents compound numbers
aDetermined by 1H NMR
bHigh-pressure Hg Lamp, 35 h
1 3

Photoinduced selective hydrophosphinylation of allylic…
Ph2P
O
OPh
OPh
ꢁ
h
ꢀ
(
> 300 nm)
neat
Ph2P
O
OPh
+
OPh
2c
5.0 equiv.
3ac
4ac
0.20 mmol
0%
Scheme 4 An attempted addition of 3ac to 2c under light
Scheme 5 A proposed mechanism of the radical addition of 1a to 2c
aford only 3cc in high yield, because the lower BDE of the P–H bond accelerates
the hydrogen abstraction of the generated carbon radical from the P–H compounds.
The photoinduced reaction of phosphine selenide (Ph2P(Se)H, 1d) with 2c aforded
the adduct 3dc in 96% yield along with only 4% of the adduct 4dc (entry 4). Two
other Ar2P(O)H, 1e and 1f were also investigated. While Ar2P(O)H with a meth-
oxy group as an electron-donating group gave 3ec and 4ec in 36% and 27% yields,
respectively (entry 5), Ar2P(O)H with a fuoro group as an electron-withdrawing
group gave the adducts 3fc and 4fc in 44% and 9% yields, respectively (entry 6).
However, the hydrophosphinylation with diethyl phosphonate (1g) did not produce
the corresponding adducts (entry 7). The above results show that the ratios of the
adducts 3 and 4 depend on the nature of substituents on the phosphorus atom.
To clarify whether 3ac is a precursor for 4ac, the photoinduced reaction of 2c and
3ac was conducted as shown in Scheme 4. As the result, no 4ac was formed, and
this fact indicates 3ac is not a precursor for 4ac.
A possible pathway is proposed in Scheme 5. Upon photoirradiation, 1a gener-
ates phosphinoyl radical (Ph2P(O)•), which adds to 2c to aford carbon-centered
radical A. Hydrogen abstraction by radical A from 1a produces anti-Markovnikov
adduct 3ac [41, 42]. The radical A also adds to another 2c to produce adduct 4ac.
To get some information about the formation of 4, we estimated the electronic
efect of the allylic substituents and the phosphorus substituents by using chemi-
1
cal shifts of allylic protons in H NMR spectra. Table 4 indicates the substituent
1 3

D. P. Tran et al.
Table 4 The reactivity of allylic compounds
O
Ph2P
O
R
R
l
h
n
( > 300 nm)
Ph2P
O
R
+
+
Ph2PH
R
neat, rt, 18 h
3
4
0.20 mmol
5.0 equiv.
Yieldb
[ppm]a
D
d
Entry
Allylic compound Corresponding alkane
4
3
OPh
1
0.53
0.39
0.33
56%
28%
OPh
H H
O
O
55%
82%
2
3
27%
8%
O
O
H H
O
O
H
H
H
H
OH
4
5
0.25
0
88%
99%
2%
0%
OH
nHex
nHex
H
H
aBasedon the chemical shift of n-octane
1
bDetermined by H NMR
chemical shift values (∆δ), which can be calculated by the shift values of allylic
methylene protons of functionalized alkenes toward the methylene chemical shift
of n-octane. An increase in the electron-withdrawing ability of the allylic substitu-
ents results in a downfeld shift of the allylic protons, and increasing the ∆δ values
resulted in increase of the yields of 4. By referring the ∆δ values, the reactivity of
the allylic compounds could be predicted. The more reactive allylic compounds led
to the higher yields of the adduct 4. In other words, as the electron-withdrawing
ability of the allylic substituent increased, the yield of 3 decreased and the yield of 4
increased.
Electronic efects of the photoinduced multiple addition of 1a to allylic com-
pounds 2 are summarized in Scheme 6. Scheme 6a indicates the structures of radical
intermediates A* and B*, which are generated from the single and duplicate addi-
tion, respectively. In these radical intermediates, the location of Ph2P(O) group
against the carbon radical center afects the stability of radical intermediates A* and
B*. Since the distance between the Ph2P(O) group and the carbon-centered radical
on the radical B* was longer than that on the radical A*, the radical B* was less
stable than the radical A*. The electron-withdrawing ability of the heteroatoms con-
tributed slightly to the stabilization of the radical species, as there was no signifcant
diference in the signal of the protons at the β positions of compounds 3ao, 3co, and
3eo (Scheme 6b). The stability of radical intermediates is afected by many factors
1 3

Photoinduced selective hydrophosphinylation of allylic…
(a)
(b)
Scheme 6 The substituent efect on the stability of the radicals
including the electronic efect of substituents on both allylic compounds and phos-
phorus reagents, the steric hindrance, and the distance between Ph2P(O) group and
the carbon radicals generated.
Conclusion
A series of γ-functionalized phosphine ligand precursors, Ph2P(O)–CH2CH2CH2–X,
(X=functional group), are conveniently synthesized by the radical addition of
diphenylphosphine oxide (Ph2P(O)H) to allylic compounds under photoirradiation.
The photoinduced addition proceeds regioselectively in an anti-Markovnikov man-
ner, and organophosphorus compounds having hydroxy, alkoxy, aryloxy, acyloxy,
and thio groups at the γ-position can be prepared by simple operation. The stabil-
ity of carbon radicals contribute to the selectivity of the single/duplicate addition,
and it is afected by the electron-withdrawing ability of allylic compounds, the steric
hindrance, the nature of phosphorus substituents, and the distance from carbon-cen-
tered radicals to Ph2P(O) group.
Experimental section
General methods
Unless otherwise state, materials were obtained from commercial supplies and
1
purifed by distillation. H NMR spectra were recorded on a JEOL JNM-ECS400
(400 MHz) system or JEOL JNM-ECX400 (400 MHz) FT system in CDCl3 as the
solvent with tetramethylsilane (TMS) as an internal standard. 13C NMR spectra
were taken mainly on a JEOL JNM-ECS400 (100 MHz) and JEOL JNM-ECX400
(100 MHz) FT spectrometers in CDCl3. 31P NMR spectra were recorded on JEOL
JNM-ECX400 (162 MHz) FT NMR in CDCl3 with 85% H3PO4 solution as an
external standard. IR spectra were recorded on JASCO FT/IR-680Plus instrument.
1 3

D. P. Tran et al.
High-resolution mass spectra (HRMS) were recorded on a Bruker micrOTOF II
ESI(+)/TOF instrument.
General procedure for hydrophosphinylation of alkenes
Under argon atmosphere, diphenylphosphine oxide 1a (0.20 mmol) and alkene 2
(1.00 mmol) were placed in a Schlenk tube in the absence of solvents. The reaction
was irradiated with a Xenon lamp (500 W) at room temperature for 18 h. The prod-
ucts were purifed by preparative TLC on silica gel or silica gel column chromatog-
raphy using iso-hexane/methyl acetate as an eluent.
(3‑Phenoxypropyl)diphenylphosphine oxide (3ac)
[CAS No. 14580–96-2] [41, 42]: 1H NMR (CDCl3) δ 7.80–7.70 (m, 4H), 7.56–7.43
(m, 6H), 7.26–7.20 (m, 2H), 6.92 (t, J=7.3 Hz, 1H), 6.83 (d, J=8.7 Hz, 2H), 3.99 (t,
J=6.0 Hz, 2H), 2.51–2.44 (m, 2H), 2.15–2.06 (m, 2H); 13C NMR (CDCl3) δ 158.6,
132.8 (d, J=98.7 Hz), 131.8, 130.7 (d, J=9.5 Hz), 129.4, 128.7 (d, J=11.5 Hz),
120.8, 114.4, 67.4 (d, J=14.1 Hz), 26.4 (d, J=72.7 Hz), 21.8; 31P NMR (CDCl3) δ
33.3.
(5‑Phenoxy‑2‑(phenoxymethyl)pentyl)diphenylphosphine oxide (4ac)
Colorless oil, 1H NMR (CDCl3) δ 7.80–7.73 (m, 4H), 7.50–7.35 (m, 6H), 7.28–7.20
(m, 4H), 6.92 (td, J=7.3, 3.2 Hz, 2H), 6.83 (d, J=7.8 Hz, 2H), 6.78 (d, J=7.8 Hz,
2H), 3.98–87 (m, 4H), 2.72–2.64 (m, 1H), 2.49–2.40 (m, 1H), 1.88–1.79 (m,
4H); 13C NMR (CDCl3) δ 158.9 (d, J=Hz), 133.5 (d, J=24.9 Hz), 131.8, 130.8
(dd, J=13.9, 9.6 Hz), 129.5 (d, J=3.8 Hz), 128.8 (dd, J=11.5, 7.7 Hz), 120.7 (d,
J=13.4 Hz), 114.6 (d, J=5.8 Hz), 69.5 (d, J=6.7 Hz), 67.7, 33.2 (d, J=2.9 Hz),
31.3 (d, J=70.9 Hz), 29.5 (d, J=8.6 Hz), 26.4; 31P NMR (CDCl3) δ 31.8; IR (KBr,
cm−1): 3420, 3057, 2927, 1586, 1496, 1437, 1243, 1173, 1105, 1036, 753, 692,
592, 510; HRMS (ESI+/TOF) m/z: [M+Na]+ Calcd. for C30H31NaO3P: 493.1909,
Found: 493.1918.
(2‑(Cyclohexyloxy)ethyl)diphenylphosphine oxide (3ak)
1
White solid, mp. 116–117 °C; H NMR (400 MHz, CDCl3): δ 7.75 (dt, J=11.8,
1.4 Hz, 2H), 7.73 (dd, J=11.8, 1.4 Hz, 2H), 7.52–7.42 (m, 6H), 3.80–3.74 (m,
2H), 3.19–3.14 (m, 1H), 2.66–2.59 (m, 2H), 1.74–1.73 (m, 2H), 1.64–1.61 (m,
2H), 1.48–1.43 (m, 1H), 1.18–1.12 (m, 5H, axial position); 13C NMR (100 MHz,
CDCl3): 133.3 (d, JC-P =99.2 Hz), 131.8 (d, JC-P =1.9 Hz), 130.8 (d, JC-P =9.5 Hz),
128.7 (d, JC-P =12.4 Hz), 77.8, 61.1, 32.1, 31.4 (d, JC-P =70.6 Hz), 25.8, 24.0; 31P
NMR (162 MHz, CDCl3): δ 29.8; HRMS (ESI+/TOF) m/z: [M+Na]+ Calcd. for
C20H25NaO2P: 351.1490, Found: 351.1490.
1 3

Photoinduced selective hydrophosphinylation of allylic…
Acknowledgements DPT is grateful for the support of the Ministry of Education, Culture, Sports, Sci-
ence and Technology (MEXT) Scholarship Program. This research was supported by JSPS KAKENHI
(B, 19H02791), (B, 19H02756), and (19K17746), from the Ministry of Education, Culture, Sports, Sci-
ence and Technology, Japan, and by Kyoto-NAIST Advanced Nanotechnology Network.
References
1. M. Dutartre, J. Bayardon, S. Jugé, Chem. Soc. Rev. 45, 5771 (2016)
2. W. Tang, X. Zhang, Chem. Rev. 103, 3029 (2003)
3. W. Cabro, I. Candiani, Acc. Chem. Rev. 95, 2457 (1995)
4. M.M. Abdou, R.A. El-Saeed, Bioorg. Chem. 90, 103039 (2019)
5. S.-i. Kawaguchi, A. Ogawa, Future trends in organophosphorus chemistry, in Organophosphorus
chemistry: from molecules to applications. ed. by V. Iaroshenko (Wiley, New Jersey, 2019)
6. A. Sato, H. Yorimitsu, K. Oshima, Angew. Chem. Int. Ed. 44, 1694 (2005)
7. L.-B. Han, C.-Q. Zhao, J. Org. Chem. 70, 10121 (2005)
8. S.-i. Kawaguchi, S. Nagata, T. Shirai, K. Tsuchii, A. Nomoto, A. Ogawa, Tetrahedron Lett. 47, 3919
(2006)
9. T. Shirai, S.-i. Kawaguchi, A. Nomoto, A. Ogawa, Tetrahedron Lett. 49, 4043 (2008)
10. T. Wada, A. Kondoh, H. Yorimitsu, K. Oshima, Org. Lett. 10, 1155 (2008)
11. S.-i. Kawaguchi, T. Shirai, T. Ohe, A. Nomoto, M. Sonoda, A. Ogawa, J. Org. Chem. 74, 1751
(2009)
12. S.-i. Kawaguchi, T. Ohe, T, Shirai, A. Nomoto, M. Sonoda, A. Ogawa, Organometallics 29, 312
(2010)
13. H. Yorimitsu, Beilstein J. Org. Chem. 9, 1269 (2013)
14. Y. Unoh, K. Hirano, T. Satoh, M. Miura, Angew. Chem. Int. Ed. 52, 12975 (2013)
15. Y.-R. Chen, W.-L. Duan, J. Am. Chem. Soc. 135, 16754 (2013)
16. J. Ke, Y. Tang, H. Yi, Y. Li, Y. Cheng, C. Liu, A. Lei, Angew. Chem. Int. Ed. 54, 6604 (2015)
17. Y. Sato, S.-i. Kawaguchi, A. Nomoto, A. Ogawa, Angew. Chem. Int. Ed. 55, 9700 (2016)
18. Y. Saga, Y. Mino, S-i. Kawaguchi, D. Han, A. Ogawa, L.-B. Han, Tetrahedron: Asymmetry 28, 84
(2017)
19. J. Yuan, W.-P. To, Z.-Y. Zhang, C.-D. Yue, S. Meng, J. Chen, Y. Liu, G.-A. Yu, C.-M. Che, Org.
Lett. 20, 7816 (2018)
20. Y. Sato, S.-i. Kawaguchi, A. Nomoto, A. Ogawa, Chem. Eur. J. 25, 2295 (2019)
21. Y. Sato, M. Nishimura, S.-i. Kawaguchi, A. Nomoto, A. Ogawa, Chem. Eur. J. 25, 6797 (2019)
22. F. Alonso, I.P. Beletskaya, M. Yus, Chem. Rev. 104, 3079 (2004)
23. Y. Okugawa, K. Hirano, M. Miura, Angew. Chem. Int. Ed. 55, 13558 (2016)
24. K. Hirano, M. Miura, Tetrahedron Lett. 58, 4317 (2017)
25. J. Yang, T. Chen, L.-B. Han, J. Am. Chem. Soc. 137, 1782 (2015)
26. I. Wauters, W. Debrouwer, C.V. Stevens, Beilstein J. Org. Chem. 10, 1064 (2014)
27. J. Xuan, T.-T. Zeng, J.-R. Chen, L.-Q. Lu, W.-J. Xiao, Chem. Eur. J. 21, 4962 (2015)
28. J.-S. Shu, T. Chen, J. Yang, L.-B. Han, Chem. Commun. 51, 7540 (2015)
29. Y. Liu, B. Ding, D. Liu, Z. Zhang, Y. Liu, W. Zhang, Res. Chem. Intermed. 43, 4959 (2017)
30. C.-J. Li, J. Lu, Z.-X. Zhang, K. Zhou, Y. Li, G.-H. Qi, Res. Chem. Intermed. 44, 4547 (2018)
31. R. Isshiki, K. Muto, J. Yamaguchi, Org. Lett. 20, 1150 (2018)
32. D. Enders, A. Saint-Dizier, M.-I. Lanou, A. Lenzen, Eur. J. Org. Chem. 2006, 29 (2006)
33. L. Coudray, J.-L. Montchamp, Eur. J. Org. Chem. 2008, 3601 (2008)
34. C. M. Jessop, A. F. Parsons, A. Routledge, D. J. Irivine, Eur. J. Org. Chem. 2006, 1547 (2006)
35. D. Semenzin, G. Etemad-Moghadam, D. Albouy, O. Diallo, M. Koenig, J. Org. Chem. 62, 2424
(1997)
36. T. Bunlaksananusorn, P. Knochel, Tetrahedron Lett. 43, 5817 (2002)
37. C.M. Jessop, A.F. Parsons, A. Routledge, D. Irvine, Tetrahedron Lett. 44, 479 (2003)
38. O. Tayama, A. Nakano, T. Iwahama, S. Sakaguchi, Y. Ishii, J. Org. Chem. 69, 5494 (2004)
39. C. Midrier, M. Lantsoght, J.-N. Volle, J.-L. Pirat, D. Virieux, C.V. Stevens, Tetrahedron Lett. 52,
6693 (2011)
40. L. Liu, D. Zhou, J. Dong, Y. Zhou, S.-F. Yin, L.-B. Han, J. Org. Chem. 83, 4190 (2018)
1 3

D. P. Tran et al.
41. S.-i. Kawaguchi, A. Nomoto, M. Sonoda, A. Ogawa, Tetrahedron Lett. 50, 624 (2009)
42. T. Huang, Y. Saga, H. Guo, A. Yoshimura, A. Ogawa, L.-B. Han, J. Org. Chem. 83, 8743 (2018)
43. M. Hatano, T. Horibe, K. Ishihara, Angew. Chem. Int. Ed. 52, 4549 (2013)
44. Y. Zhao, T. Chen, D. Han, C.-Q. Zhao, L.-B. Han, Org. Lett. 16, 6152 (2014)
45. T.-Z. Huang, T. Chen, Y. Saga, L.-B. Han, Tetrahedron 73, 7085 (2017)
46. A.V. Salin, A.V. Il;in, R.I. Faskhutdinow, V.I. Galkin, D.R. Islamov, O.N. Kataeva, Tetrahedron Lett
59, 1630 (2018)
47. L.-B. Han, N. Choi, M. Tanaka, Organometallics 15, 3259 (1996)
48. L.-B. Han, M. Tanaka, J. Am. Chem. Soc. 118, 1571 (1996)
49. L.-B. Han, R. Hua, M. Tanaka, Angew. Chem. Int. Ed. 37, 94 (1998)
50. L.-B. Han, M. Tanaka, Chem. Commun. 5, 395 (1999)
51. L.-B. Han, F. Mirzaei, C.-Q. Zhao, M. Tanaka, J. Am. Chem. Soc. 122, 5407 (2000)
52. L.-B. Han, C.-Q. Zhao, M. Tanaka, J. Org. Chem. 66, 5929 (2001)
53. C.-Q. Zhao, L.-B. Han, M. Goto, M. Tanaka, Angew. Chem. Int. Ed. 40, 1929 (2001)
54. S.I. Kawaguchi, S. Nagata, A. Nomoto, M. Sonoda, A. Ogawa, J. Org. Chem. 73, 7928 (2008)
55. Y. Gao, G. Wang, L. Chen, P. Xu, Y. Zhao, Y. Zhou, L.-B. Han, J. Am. Chem. Soc. 131, 7956
(2009)
56. Q. Xu, L.-B. Han, J. Organomet. Chem. 696, 130 (2011)
57. A. Yoshimura, Y. Saga, Y. Sato, A. Ogawa, T. Chen, L.-B. Han, Tetrahedron Lett. 57, 3382 (2016)
58. T. Chen, C.-Q. Zhao, L.-B. Han, J. Am. Chem. Soc. 140, 3139 (2018)
59. S.-Z. Nie, R.T. Davison, V.M. Dong, J. Am. Chem. Soc. 140, 16450 (2018)
60. Y.A. Rina, J.A.R. Schmidt, Organometallics 38, 4261 (2019)
61. S.-i. Kawaguchi, Y. Yamamoto, A. Ogawa, Mendeleev Commun. 30, 129 (2020)
62. T. Hirai, L.-B. Han, Org. Lett. 9, 53 (2007)
63. W.-J. Yoo, S. Kobayashi, Green Chem. 15, 1844 (2013)
64. B. Zhang, C.G. Daniliuc, A. Studer, Org. Lett. 16, 250 (2014)
65. Z. Li, F. Fan, Z. Zhang, Y. Xiao, D. Liu, Z.-Q. Liu, RSC Adv. 5, 27853 (2015)
66. H. Guo, A. Yoshimura, T. Chen, Y. Saga, L.-B. Han, Green Chem. 19, 1502 (2017)
67. Y. Yamamoto, S.-i. Kawaguchi, M. Nishimura, Y. Sato, Y. Shimada, A. Tabuchi, A. Nomoto, A.
Ogawa, J. Org. Chem. 85, 14684 (2020)
Publisher’s Note Springer Nature remains neutral with regard to jurisdictional claims in published
maps and institutional afliations.
1 3