Palladium-catalyzed R2(O)P-directed C(sp2)-H activation

Article abstract of DOI:10.1007/s11426-015-5382-1

In recent years, transition-metal-catalyzed inert C-H bond activation has developed rapidly and is a powerful protocol for the construction of new C-C or C-X bonds and the introduction of new functional groups. Our group has also developed a series of R₂(O)P-directed Pd-catalyzed C-H functionalizations involving olefination, hydroxylation, acetoxylation, arylation, and acylation through an uncommon seven-membered cyclo-palladium pretransition state. Unlike previously used directing groups, the R₂(O)P group acts as a directing group and is also involved in the construction of P,-hetero-ligands.

Full text of DOI:10.1007/s11426-015-5382-1

SCIENCE CHINA
Chemistry
• FEATURE ARTICLES •
doi: 10.1007/s11426-015-5382-1
· SPECIAL ISSUE · CH bond activation
Palladium-catalyzed R2(O)P-directed C(sp2)–H activation
Hongyu Zhang & Shangdong Yang*
State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, China
Received November 21, 2014; accepted December 5, 2014
In recent years, transition-metal-catalyzed inert C–H bond activation has developed rapidly and is a powerful protocol for the
construction of new C–C or C–X bonds and the introduction of new functional groups. Our group has also developed a series
of R2(O)P-directed Pd-catalyzed C–H functionalizations involving olefination, hydroxylation, acetoxylation, arylation, and ac-
ylation through an uncommon seven-membered cyclo-palladium pretransition state. Unlike previously used directing groups,
the R2(O)P group acts as a directing group and is also involved in the construction of P,-hetero-ligands.
C–H bond activation, Pd-catalyzed, R2(O)P-directed
ladium intermediate. In the last year, we have focused on
1 Introduction
establishing efficient and widespread catalytic systems and
have reported a series of R2(O)P-directed Pd-catalyzed C–H
functionalizations involving olefination [47], hydroxylation
[48], acetoxylation [49], arylation [50] and acylation [51]
(Scheme 1). These methods provide a concise and effective
route for the preparation of substituted chiral 2′-phosphoryl-
biphenyl compounds [52]. We expect that our results will
have a significant impact in this field.
Transition-metal-catalyzed directed selective C–H activa-
tion and functionalization has become a powerful tool in
organic synthesis because of its significance in basic studies
of inert C–H bond chemistry, and its broad substrate range
and high atom economy in potential synthetic applications.
[1–5]. Over the past ten years, much effort has been devoted
to this strategy and many directing groups such as heterocy-
cles [6–9], amides [10–14], imines [15–17], ketones
[18–23], esters [24–29], and carboxylic acid [30–33] have
been identified. Here, we report the use of the relatively
weak coordinating R2(O)P group as a new directing group
with great promise for improving catalytic turnovers and
broadening reaction scopes. Compared with previously re-
ported directing groups, R2(O)P has some useful features: (1)
organophosphorus molecules occur widely as structural mo-
tifs in the life sciences and pharmaceuticals [34–37]; (2) the
R2(O)P group acts as a directing group, and is also involved
in the construction of the desired products [38]; (3) unlike
previously reported syntheses involving C–H functionaliza-
tions directed by phosphoric acid or phosphate esters
[39–46], our reactions feature a seven-membered cyclopal-
Scheme 1 P(O)R2-directed C–H functionalization via seven-membered
cyclopalladium transition state.
*Corresponding author (email: yangshd@lzu.edu.cn)
© Science China Press and Springer-Verlag Berlin Heidelberg 2015
chem.scichina.com link.springer.com

2
Zhang et al. Sci China Chem June (2015) Vol.58 No.6
We evaluated various diphenylphosphine oxide deriva-
2 Results and discussion
tives and phosphate directing groups under the optimum
conditions. These compounds were also effective in this
transformation and corresponding products were obtained in
good yields. We discovered that styrenes were also
compatible with the C–H olefination reaction. Triphenyl-
phosphine oxide and (naphthalen-1-yl)diphenylphosphine
oxide failed to induce C–H olefination. These results imply
that a seven-membered cyclopalladium pre-transition state
may play a critical role in this transformation.
2.1 R2(O)P-directed Pd(II)-catalyzed C–H olefination
We first explored R2(O)P-directed Pd(II)-catalyzed C–H
olefination of structure C–C bonds via Heck reaction [53].
We chose this reaction for two reasons: (1) Heck coupling
reactions have become an indispensable strategic tool for
C–C bond formation and play a pivotal role in modern or-
ganic synthesis. The development of complementary meth-
ods for coupling inactivated C–H bonds with olefins is
therefore attractive; (2) the expected products are precursors
of olefin-phosphine hybrid ligands. 2-Diphenylphosphino-
2′-methylbiphenyl (1aa) and ethyl acrylate (1ac) were used
as the model substrates in the initial tests. The optimum
reaction conditions were found to be Pd(OAc)2 (5 mol%) as
the catalyst, Ac–Gly–OH (10 mol%) as the ligand, and
AgOAc (3.0 equiv.) as the oxidant, in CF3CH2OH (2.0 mL),
with 1aa (0.2 mmol) and ethyl acrylate (3.0 equiv.) at
100 °C in air (Table 1).
2.2 R2(O)P-directed Pd(II)-catalyzed C–H hydroxyla-
tion
Inspired by these results, we extended this method to
R2(O)P-directed Pd(II)-catalyzed C–H hydroxylation, these
products are important precursors in syntheses of various
P,-O-ligands. Also, phenols function as important building
blocks for common subunits in biomolecules and drug mol-
ecules [54]. We found that the best conditions were Pd(CF3-
COO)2/PhI(CF3COO)2 as the catalytic system, CH3NO2 as
the solvent, 60 °C, and an air atmosphere (Table 2).
Table 1 R2(O)P-directed Pd(II)-catalyzed C–H olefination a)
Table 2 R2(O)P-directed Pd(II)-catalyzed C–H hydroxylation a)
Yield
(%) b)
Yield
(%) b)
Entry
Product
Entry
Product
Yield
(%) b)
Yield
(%) b)
Entry
Product
Entry
Product
1ab
87
62
54
1bb
67
31
2ab
85
2bb
76
1cb
1eb
1gb
1ib
1db
1fb
2cb
2eb
87 c)
2db
2fb
93 c)
60
90 c)
73 d)
68 c) 1hb
67 c)
2gb
2ib
83
66
2hb
2jb
81
37
58
0
1jb
1lb
87
P(O)Ph2
HO
1kb
0
a) All reactions were carried out in the presence of 0.3 mmol of 2aa–2ja
in 2.0 mL CH3NO2; b) isolated yield; c) 10 mol% Pd(CF3COO)2 was used
at 80 °C; d) 1.4 equiv. of PhI(CF3COO)2 was used.
a) All reactions were carried out in the presence of 0.2 mmol of 1aa–1ja
in 2.0 mL CF3CH2OH; b) isolated yield; c) 10 mol% Pd(OAc)2 was used.

Zhang et al. Sci China Chem June (2015) Vol.58 No.6
3
The reaction had good functional-group tolerance and
substrates scope. Electron-withdrawing substituents such as
F, Cl, and CF3 at the 4′-position gave the corresponding
products in excellent yields in the presence of 10 mol%
Pd(CF3COO)2 at 80 °C (2cb–2eb). However, for a methoxy
substituent at this position, the oxidant loading had to be
decreased to 1.4 equiv. (2fb). When diethylbiphenyl-2-
ylphosphonate was used, only phosphoryl lactone 2jb was
obtained, in 37% yield.
functional groups to proceed smoothly, and the correspond-
ing products were obtained in good yields (Table 3).
2.4 R2(O)P-directed Pd(II)-catalyzed C–H arylation
In the meantime, similar hypervalent iodine reagents were
used to synthesize a series of polyaromatic monophospho-
rus compounds via R2(O)P-directed Pd(II)-catalyzed C–H
arylation. These compounds can be easily reduced to triva-
lent phosphorus by trichlorosilane, which are useful ligands
for transition-metal-catalyzed cross-coupling reactions [55].
After systematic studies, we concluded that the cheap PdCl2
catalyst with pivalic acid/Ag2CO3 as an additive was the
best choice. Under the optimized conditions, various poly-
aromatic monophosphorus compounds were obtained in
moderate to good yields. Hypervalent iodine arylation rea-
gents also reacted smoothly to give various substituted
products (Table 4).
2.3 R2(O)P-directed Pd(II)-catalyzed C–H acetoxylation
The above results suggest that using more moderately active
PhI(OAc)2 as the oxidant might lead to acetoxylation under
a similar catalytic system, because the phenol products of
hydroxylation might derive from the labile corresponding
trifluoroacetation. We obtained the desired acetoxylation
products using Pd(OAc)2 as the catalyst and PhI(OAc)2 as
the oxidant in CF3CH2OH. The moderate oxidant enabled
the reactions of compounds with some useful and sensitive
2.5 R2(O)P-directed Pd(II)-catalyzed C–H acylation
Based on these results, we have developed an efficient
Table 3 R2(O)P-directed Pd(II)-catalyzed C–H acetoxylation a)
Table 4 R2(O)P-directed Pd(II)-catalyzed C–H arylation a)
Yield
(%) b)
Yield
(%) b)
Entry
Product
Entry
Product
Yield
(%) b)
Yield
(%) b)
Entry
Product
Entry
Product
3ab
87
3bb
82
4ab
83
4bb
67
3cb
3eb
77
3db
3fb
79
4cb
4eb
72
4db
66
P(O)Ph2
OAc
O
PiPr2
O
PiPr2
45
43
63 c) 4fb
70 c)
COOEt
Cl
4gb
4ib
56 c) 4hb
60 c)
3gb
3ib
55
58
3hb
3jb
64
80
67 c) 4jb
62 c)
a) All reactions were carried out in the presence of 0.2 mmol of 4aa–4ja,
4ac–4jc (2.5 equiv.), PdCl2 (10 mol%), Ag2CO3 (0.2 equiv.), PivOH (2.0
equiv.), DMF (4.0 mL); b) isolated yield; c) PdCl2 (20 mol%), Ag2CO3 (0.4
equiv.) was used.
a) All reactions were carried out in the presence of 3aa–3ja (0.2 mmol),
PhI(OAc)2 (3.0 equiv.), Pd(OAc)2 (10 mol%), CF3CH2OH (2.0 mL), air
atmosphere, 100 oC; b) isolated yields of products.

4
Zhang et al. Sci China Chem June (2015) Vol.58 No.6
Table 6 R2(O)P-directed Pd(II)-catalyzed C–H acylation of alcohols a)
method for the synthesis of 2-phosphorylbiphenyl ketones
by Pd-catalyzed C–H acylation with -oxocarboxylic acids.
After systematic screening, the desired product was ob-
tained in 72% yield in the presence of Pd(OAc)2 (10 mol%)
and phenylglyoxylic acid (2.0 equiv.) at 130 °C in CH3CN
using K2S2O8 (2.5 equiv.) as the oxidant. We then investi-
gated the reactions of various substituted 2-phosphorylbi-
phenyl derivatives and -oxocarboxylic acids; the reactions
gave the mono-acylation products in all cases (Table 5).
We then performed these reactions using cheaper and
readily available benzyl alcohols. After screening various
oxidants and solvents, the desired acylated product was ob-
tained in 80% yield with a good ratio (10:1) of mono-
acylation to diacylation. The aliphatic alcohol ethanol was
also compatible with this reaction, but the yield was low
(6jb, Table 6).
Yield
(%) b)
Yield
Entry
Product
Entry
Product
(%) b)
6ab
&
6ad
80
(10:1)
6bb
50
6db
&
6dd
74
(8:1)
6cb
50
6eb
&
6ed
6fb
&
6fd
68
(8:1)
67
(8:1)
2.6 Preparation of substituted chiral 2′-phosphorylbi-
phenyl compounds
6gb
&
6gd
6hb
&
6hd
75
(7:1)
76
(7:1)
Phosphorus ligands play important roles in many metal-
catalyzed organic transformations, including many asym-
metric reactions [56,57]. The specific characteristics of
these ligands are particularly in enhancing the metal catalyst
efficiency and controlling chiral induction. The development
6ib
&
6id
76
(12:1)
6jb
27
a) All reactions were carried out in the presence of 0.3 mmol of 6aa–6ja
and 6ac–6jc (4.0 equiv.) in 1.5 mL DCE at 60 ºC; b) isolated yield.
Table 5 R2(O)P-directed Pd(II)-catalyzed C–H acylation a)
of concise and efficient ways to construct various ligands is
desirable. We easily synthesized various substituted chiral
2′-phosphorylbiphenyl compounds using the commercially
available chiral binaphthyl-based diphenylphosphine oxide
(R)-1 as the substrate. The ease of this reaction is largely
thanks to our R2(O)P-directed Pa-catalyzed C–H function-
alization (Table 7).
Yield
(%) b)
Yield
(%) b)
Entry
Product
Entry
Product
O
P(O)iPr2
5ab
72 5bb
50 5db
54
68
2.7 Proposed mechanisms
Ph
Finally, we discuss the reaction mechanism, using R2(O)P-
directed Pd(II)-catalyzed C–H olefination as an example. A
plausible mechanistic pathway based on our experimental
results and previous reports [58,59] is shown in Scheme 2.
Pd(OAc)2 first coordinates with the Ac–Gly–OH ligand to
form the activate Pd catalyst, which reacts with substrate 1a
by electronic substitution to produce the cyclopalladium
intermediate 1A. This active pretransition intermediate then
undergoes olefin insertion with ethyl acrylate to form com-
plex 1B, which then undergoes Heck-type olefination to
give the intermediate 1C. Finally, the product 2a is pro-
duced by reductive elimination, and the catalyst reinitiates
the catalytic cycle.
5cb
5eb
O
P(O)tBuPh
77
5fb
62
5gb
5ib
68 5hb
58
64
O
P(O)tBuPh
52
5jb
MeO
3 Conclusions and outlook
a) All reactions were carried out in the presence of 0.3 mmol of 5aa–5ja
and 5ac–5jc (2.0 equiv.) in 3 mL CH3CN at 130 ºC; b) isolated yield.
We developed original and efficient R2(O)P-directed Pd-

Zhang et al. Sci China Chem June (2015) Vol.58 No.6
5
Table 7 Preparation of substituted chiral 2′-phosphorylbiphenyl com-
axially chiral oxygen-phosphine or olefin-phosphine ligands.
Further studies on axially asymmetric induction are ongoing
in our laboratory.
pounds a)
This work was supported by the Natural Science Foundation of Gansu
Province (1208RJZA216).
1
2
Li BJ, Shi ZJ. From C(sp2)–H to C(sp3)–H: systematic studies on
transition metal-catalyzed oxidative C–C formation. Chem Soc Rev,
2012, 41: 5588–5598
Engle KM, Mei TS, Wasa S, Yu JQ. Weak coordination as a power-
ful means for developing broadly useful C–H functionalization reac-
tions. Acc Chem Res, 2012, 45: 788–802
3
4
Wencel-Delord J, Droge T, Liu F, Glorius F. Towards mild metal-
catalyzed C–H bond activation. Chem Soc Rev, 2011, 40: 4740–4761
Arockiam PB, Bruneau C, Dixneuf PH. Ruthenium(II)-catalyzed
C–H bond activation and functionalization. Chem Rev, 2012, 112:
5879–5918
5
6
Lyons TW, Sanford MS. Palladium-catalyzed ligand-directed C−H
functionalization reactions. Chem Rev, 2010, 110: 1147–1169
Brasse M, Cámpora J, Ellman JA, Bergman RG. Mechanistic study
of the oxidative coupling of styrene with 2-phenylpyridine deriva-
tives catalyzed by cationic rhodium(III) via C–H activation. J Am
Chem Soc, 2013, 135: 6427–6430
7
8
9
Kalyani D, Deprez NR, Desai LV, Sanford MS. Oxidative C−H acti-
vation/C−C bond forming reactions: synthetic scope and mechanistic
insights. J Am Chem Soc, 2005, 127: 7330–7331
Li Y, Li BJ, Wang WH, Huang WP, Zhang XS, Chen K, Shi ZJ.
Rhodium-catalyzed direct addition of aryl C–H bonds to N-sulfonyl
aldimines. Angew Chem Int Ed, 2011, 50: 2115–2119
Yan Y, Feng P, Zheng QZ, Liang YF, Lu JF, Cui Y, Jiao N. PdCl2
and N-hydroxyphthalimide co-catalyzed Csp2–H hydroxylation by
dioxygen activation. Angew Chem Int Ed, 2013, 52: 5827–5831
a) The yield was isolated and the ee value was determined by HPLC; b)
7aa–7ca, 7ia (0.3 mmol), 7ac–7cc, 7ic (0.9 mmol), Pd(OAc)2 (10 mol%),
Ac-Gly–OH (20 mol%), AgOAc (0.9 mmol), CF3CH2OH (3.0 mL), 100 °C,
24 h, air atmosphere; c) 7da–7ea (0.3 mmol), Pd(CF3COO)2 (10 mol%),
PhI(CF3COO)2 (0.45 mmol), CH3NO2 (3.0 mL), 60 °C, 24 h, air atmos-
phere; d) 7fa–7ga (0.3 mmol), Pd(OAc)2 (10 mol%), PhI(OAc)2 (0.9
mmol), CF3CH2OH (3.0 mL), 100 °C, 24 h, air atmosphere (0.2 mmol); e)
7ha (0.3 mmol), benzyl alcohol (0.75 mmol), Pd(CF3COO)2 (10 mol%),
TBHP (1.2 mmol), DCE (3.0 mL), at 60 °C, air atmosphere.
10 Zhao XD, Yeung CS, Dong VM. Palladium-catalyzed ortho-arylation
of O-phenylcarbamates with simple arenes and sodium persulfate. J
Am Chem Soc, 2010, 132: 5837–5844
11 Wasa M, Engle KM, Yu JQ. Pd(II)-catalyzed olefination of sp3 C−H
bonds. J Am Chem Soc, 2010, 132: 3680–3681
12 Shi ZZ, Cui YX, Jiao N. Synthesis of -and -carbolinones via
Pd-catalyzed direct dehydrogenative annulation (DDA) of indole-
carboxamides with alkynes using air as the oxidant. Org Lett, 2010,
12: 2908–2911
13 Yang F, Ackermann L. Ruthenium-catalyzed C−H oxygenation on
aryl weinreb amides. Org Lett, 2013, 15: 718–720
14 Yang SD, Li BJ, Wan XB, Shi ZJ. Ortho arylation of acetanilides via
Pd(II)-catalyzed C−H functionalization. J Am Chem Soc, 2007, 129:
6066
15 Sun CL, Liu N, Li BJ, Yu DG, Wang Y, Shi ZJ. Pd-catalyzed C−H
functionalizations of O-methyl oximes with arylboronic acids. Org
Lett, 2010, 12: 184–187
16 Neufeldt SR, Sanford MS. O-acetyl oximes as transformable direct-
ing groups for Pd-catalyzed C−H bond functionalization. Org Lett,
2010, 12: 532–535
17 Liu B, Fan Y, Gao Y, Sun C, Xu C, Zhu J. Rhodium(III)-catalyzed
N-nitroso-directed C–H olefination of arenes. High-yield, versatile
coupling under mild conditions. J Am Chem Soc, 2013, 135: 468–473
18 Shi XY, Li CJ. Synthesis of indene frameworks via rhodium-
catalyzed cascade cyclization of aromatic ketone and unsaturated
carbonyl compounds. Org Lett, 2013, 15: 1476–1479
Scheme 2 Proposed Mechanisms of R2(O)P-directed Pd(II)-catalyzed
C–H olefination.
19 Thirunavukkarasu VS, Ackermann L. Ruthenium-catalyzed C−H
bond oxygenations with weakly coordinating ketones. Org Lett, 2012,
14: 6206–6209
20 Shan G, Yang X, Ma L, Rao Y. Pd-catalyzed C−H oxygenation with
TFA/TFAA: expedient access to oxygen-containing heterocycles and
late-stage drug modification. Angew Chem Int Ed, 2012, 51: 13070–
13074
catalyzed C–H functionalizations to synthesize various sub-
stituted 2′-phosphorylbiphenyl compounds. We expect the
methods described in this paper to have significant practical
applications, especially in the synthesis of substituted

6
Zhang et al. Sci China Chem June (2015) Vol.58 No.6
21 Mo F, Trzepkowski LJ, Dong G. Synthesis of ortho-acylphenols
through the palladium-catalyzed ketone-directed hydroxylation of
arenes. Angew Chem Int Ed, 2012, 51: 13075–13079
22 Gandeepan P, Parthasarathy K, Cheng CH. synthesis of phenanthrone
derivatives from sec-alkyl aryl ketones and aryl halides via a palla-
dium-catalyzed dual C−H bond activation and enolate cyclization. J
Am Chem Soc, 2010, 132: 8569–8571
23 Shan G, Han X, Lin Y, Yu S, Rao Y. Broadening the catalyst and re-
action scope of regio- and chemoselective C−H oxygenation: a con-
venient and scalable approach to 2-acylphenols by intriguing Rh(II)
and Ru(II) catalysis. Org Biomol Chem, 2013, 11: 2318–2322
24 Yang Y, Lin Y, Rao Y. Ruthenium(II)-catalyzed synthesis of hy-
droxylated arenes with ester as an effective directing group. Org Lett,
2012, 14: 2874–2877
25 Zhang YH, Shi BF, Yu JQ. Pd(II)-catalyzed olefination of electron-
deficient arenes using 2,6-dialkylpyridine ligands. J Am Chem Soc,
2009, 131: 5072–5074
phoric acid directing group. Chem Commun, 2013, 49: 4682–4684
41 Unoh Y, Hashimoto Y, Takeda D, Hirano K, Satoh T, Miura M.
Rhodium(III)-catalyzed oxidative coupling through C–H bond cleavage
directed by phosphinoxy groups. Org Lett, 2013, 15: 3258–3261
42 Zhao D, Nimphius C, Lindale M, Glorius F. Phosphoryl-related di-
recting groups in rhodium(III) catalysis: a general strategy to diverse
P-containing frameworks. Org Lett, 2013, 15: 4504–4507
43 Jeon WH, Lee TS, Kim EJ, Moon B, Kang J. Palladium(II)-catalyzed
ortho-arylation via phosphate-group-directed C–H activation. Tetra-
hedron, 2013, 69: 5152–5159
44 Guan J, Wu GJ, Han FS. PdII-catalyzed mild C−H ortho arylation and
intramolecular amination oriented by a phosphinamide group. Chem
Eur J, 2014, 20: 3301–3305
45 Gwon D, Lee D, Kim J, Park S, Chang S. Iridium(III)-catalyzed C−H
amidation of arylphosphoryls leading to a P-stereogenic center. Chem
Eur J, 2014, 20: 12421–12425
46 Liu L, Wu Y, Wang T, Gao X, Zhu J, Zhao Y. Mechanism, reactivity,
and selectivity in Rh(III)-catalyzed phosphoryl-directed oxidative
C−H activation/cyclization: a DFT study. J Org Chem, 2014, 79:
5074–5081
26 Park SH, Kim JY, Chang S. Rhodium-catalyzed selective olefination
of arene esters via C−H bond activation. Org Lett, 2011, 13: 2372–
2375
27 Gong TJ, Xiao B, Liu ZJ, Wan J, Xu J, Luo DF, Fu Y, Liu L. Rho-
dium-catalyzed selective C–H activation/olefination of phenol car-
bamates. Org Lett, 2011, 13: 3235–3237
47 Wang HL, Hu RB, Zhang H, Zhou AX, Yang SD. Pd(II)-catalyzed
Ph2(O)P-directed C–H olefination toward phosphine-alkene ligands.
Org Lett, 2013, 15: 5302–5305
28 Graczyk K, Ma W, Ackermann L. Oxidative alkenylation of aromatic
esters by ruthenium-catalyzed twofold C–H bond cleavages. Org Lett,
2012, 14: 4110–4113
48 Zhang HY, Yi HM, Wang GW, Yang B, Yang SD. Pd(II)-catalyzed
C(sp2)–H hydroxylation with R2(O)P-coordinating group. Org Lett,
2013, 15: 6186–6189
29 Xiao B, Fu Y, Xu J, Gong TJ, Dai JJ, Yi J, Liu L. Pd(II)-catalyzed
C−H activation/aryl-aryl coupling of phenol esters. J Am Chem Soc,
2010, 132: 468–469
49 Zhang H, Hu RB, Zhang XY, Li SX, Yang SD. Palladium-catalyzed
R2(O)P directed C(sp2)–H acetoxylation. Chem Commun, 2014, 50:
4686–4689
30 Chiong HA, Pham QN, Daugulis O. Two methods for direct ortho-
arylation of benzoic acids. J Am Chem Soc, 2007, 129: 9879–9884
31 Wang DH, Mei TS, Yu JQ. Versatile Pd(II)-catalyzed C−H
activation/aryl-aryl coupling of benzoic and phenyl acetic acids. J Am
Chem Soc, 2008, 130: 17676–17677
32 Shi BF, Zhang YH, Lam JK, Wang DH, Yu JQ. Pd(II)-catalyzed en-
antioselective C−H olefination of diphenylacetic acids. J Am Chem
Soc, 2010, 132: 460–461
33 Cheng XF, Li Y, Su YM, Yin F, Wang JY, Sheng J, Vora HU, Wang
XS, Yu JQ. Pd(II)-catalyzed enantioselective C–H activation/C–O
bond formation: synthesis of chiral benzofuranones. J Am Chem Soc,
2013, 135: 1236–1239
50 Hu RB, Zhang H, Zhang XY, Yang SD. Palladium-catalyzed P(O)R2
directed C–H arylation to synthesize electron-rich polyaromatic
monophosphorus ligands. Chem Commun, 2014, 50: 2193–2195
51 Ma YN, Tian QP, Zhang HY, Zhou AX, Yang SD. P(O)R2 directed
Pd(II)-catalyzed C(sp2)–H acylation. Org Chem Front, 2014, 1: 284–
288
52 Hu RB, Wang HL, Zhang HY, Zhang H, Yang SD. P(O)R2-directed
Pd-catalyzed C–H functionalization of biaryl derivatives to synthe-
size chiral phosphorous ligands. Beilstein J Org Chem, 2014, 10:
2071–2076
53 Martin O. The Mizoroki-Heck Reaction. Weinheim: John Wiley &
Sons, Ltd., 2009
34 Jeught SV, Stevens CV. Direct phosphonylation of aromatic azahet-
erocycles. Chem Rev, 2009, 109: 2672–2702
54 Rappoport Z. The Chemistry of Phenols. Weinheim: Wiley-VCH,
2003
35 George A, Veis A. Phosphorylated proteins and control over apatite
nucleation, crystal growth, and inhibition. Chem Rev, 2008, 108:
4670–4693
36 Mathey F. Phospha-organic chemistry: panorama and perspectives.
Angew Chem Int Ed, 2003, 42: 1578–1604
37 Johansson T, Stawinski J. Studies towards synthesis of dinucleoside
arylphosphonates with metal complexing properties. Nucleos Nucleot
Nucl, 2003, 22: 1459–1461
38 Obara N, Yoshida I, Tanaka K, Kan T, Morimoto T. Copper-
catalyzed enantioselective conjugate addition of diethylzinc using
axially chiral aminoethyloxy-phosphine ligands. Tetrahedron Lett,
2007, 48: 3093–3095
55 Rutherford JL, Rainka MP, Buchwald SL. An annulative approach to
highly substituted indoles: unusual effect of phenolic additives on the
success of the arylation of ketone enolates. J Am Chem Soc, 2002,
124: 15168–15169
56 Minnaard AJ, Feringa BL, Lefort L, Vries JG. Asymmetric hydro-
genation using monodentate phosphoramidite ligands. Acc Chem Res,
2007, 40: 1267–1277
57 Martin R, Buchwald SL. Palladium-catalyzed Suzuki-Miyaura
cross-coupling reactions employing dialkylbiaryl phosphine ligands.
Acc Chem Res, 2008, 41: 1461–1473
58 Engle KM, Thuy-Boun PS, Dang M, Yu JQ. Ligand-accelerated
cross-coupling of C(sp2)–H bonds with arylboron reagents. J Am
Chem Soc, 2011, 133: 18183–18193
39 Meng X, Kim S. Palladium(II)-catalyzed ortho-olefination of ben-
zylic phosphonic monoesters. Org Lett, 2013, 15: 1910–1913
40 Chan LY, Kim S, Ryu T, Lee PH. Palladium-catalyzed ortho-
alkenylation of aryl hydrogen phosphates using a new mono-phos-
59 Li G, Leow D, Wan L, Yu JQ. Ether-directed ortho-C–H olefination
with a palladium(II)/monoprotected amino acid catalyst. Angew
Chem Int Ed, 2013, 52: 1245–1247