Ni-Catalyzed C-P Coupling of Aryl, Benzyl, or Allyl Ammonium Salts with P(O)H Compounds

Article abstract of DOI:10.1021/acs.joc.8b02926

A methodology that allows for the construction of C-P bonds via the nickel-catalyzed cross-coupling of organoammonium salts with appropriate phosphorus nucleophiles has been developed. Aryl-, pyridyl-, benzyl-, and allyl-ammonium triflates can be employed as the electrophiles. The employed phosphorus-based nucleophiles included diaryl/dibutyl phosphine oxide, dialkyl phosphonates, and ethyl phenylphosphinate. Functional groups OMe, CN, CF₃, F, Cl, C(O)NMe₂, and C(O)tBu were tolerated.

Full text of DOI:10.1021/acs.joc.8b02926

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Article
Ni-Catalyzed C-P Coupling of Aryl, Benzyl or
Allyl Ammonium Salts with P(O)H Compounds
Bo Yang, and Zhong-Xia Wang
J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.8b02926 • Publication Date (Web): 10 Jan 2019
Downloaded from http://pubs.acs.org on January 11, 2019
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Ni-Catalyzed C-P Coupling of Aryl, Benzyl or Allyl
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Ammonium Salts with P(O)H Compounds
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Bo Yang† and Zhong-Xia Wang*,†,‡
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† CAS Key Laboratory of Soft Matter Chemistry and Department of Chemistry, University of
Science and Technology of China, Hefei, Anhui 230026, P. R. China.
E-mail: zxwang@ustc.edu.cn
‡
Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin
300072, P. R. China.
Abstract: A methodology that allows for the construction of C-P bonds via the
nickel-catalyzed cross-coupling of organoammonium salts with appropriate phosphorus
nucleophiles has been developed. Aryl-, pyridyl-, benzyl- and allyl-ammonium triflates can
be employed as the electrophiles. The employed phosphorus-based nucleophiles included
diaryl/dibutyl phosphine oxide, dialkyl phosphonates, and ethyl phenylphosphinate.
Functional groups OMe, CN, CF3, F, Cl, C(O)NMe2, and C(O)tBu were tolerated.
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Introduction
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Organophosphorus compounds have found wide applications in the fields of organic
synthesis, coordination chemistry, medicinal chemistry and photoelectric materials.1
Traditional methods to construct C-P bond such as radical methods, anionic methods and the
Arbuzov reaction are well known.2 In the 1980s, Hirao and co-workers reported the
palladium-catalyzed C-P bond construction via reaction of aryl or alkenyl halides with dialkyl
phosphites.3 Since then, a range of organic or organometallic compounds including
organohalides,4 alcohol or phenol derivatives,5 diazonium salts,6 arylhydrazines,7 boronic
acids,8 silanes,9 organobismuth compounds,10 sulfides,11 aryl nitriles,12 aryl or alkenyl
carboxylic acids,13 acylphosphines,14 amides15 and aromatic esters16 were employed as the
coupling partners. Considering the importance of organophosphorus compounds and the
drawbacks of the reported methods such as harsh reaction conditions and limited substrate
scope, developing new synthetic methods and searching for alternative coupling partners are
still highly desirable.
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Organoammonium salts as readily accessible and stable coupling substrates for C-C and
C-heteroatom bond construction were reported by us and other groups.17,18 For example,
nickel-catalyzed reaction of aryl- and benzyltrimethylammonium salts with B2pin2 afforded
organoboronates via the C-N bond cleavage.18b Nickel-catalyzed cross-coupling of
aryltrimethylammonium triflates with amines resulted in the formation of new aromatic
amines.18c It is of great interest to apply organoammonium salts as electrophilic partners to
construct C-P bond via cross-coupling with P(O)H compounds. Herein we report the results.
Results and discussion
The reaction of 1-naphthyltrimethylammonium triflate (1a) with diphenylphosphine oxide
(2a) was employed to scan the catalysts and optimize the reaction conditions (Table 1).
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According to the reports before, nickel catalysts were effective for C-P bond fomation.11,14,16
We found that several nickel complexes were able to drive current reaction in MeCN in the
presence of K2CO3 and NiCl2(dppf) was superior to NiCl2(dppp), NiCl2(dppe), NiCl2(PPh3)2
and NiCl2(PCy3)2 (Table 1, entries 1-5). Next, the base was surveyed. Both NaOtBu and
KOtBu were noneffective and N,N-diisopropylethylamine (DIPEA) was less effective than
K2CO3 (Table 1, entries 6-8). Na2CO3 exhibited a similar effect to K2CO3 (Table 1, entry 9).
Further tests showed that both K3PO4 and Cs2CO3 were superior to K2CO3. Reaction
employing either K3PO4 or Cs2CO3 as a base gave almost quantitative yields (Table 1, entries
10 and 11). When 1.2 equiv of Cs2CO3 was employed, the reaction gave the same product
yield as that employing 1.5 equiv of Cs2CO3. However, use of 1.0 equiv of Cs2CO3 resulted
in a yield decrease (Table 1, entries 12 and 13). A combination of Ni(cod)2 (10 mol%) and
dppf (10 mol%) exhibited the same catalytic effect as NiCl2(dppf) (10 mol%). This implies
that the reaction might be initiated by a Ni(0) species. Ni(cod)2 also catalyzed the reaction,
but displayed a lower activity than the Ni(cod)2/dppf combination (Table 1, entries 14 and 15).
The reaction cannot occur without a nickel catalyst (Table 1, entries 16 and 17). 5 Mol% of
NiCl2(dppf) loading resulted in a decrease of the product yield (Table 1, entry 18). The
reaction was also sensitive to the reaction temperature. Lower reaction temperature than
100 °C led to markedly yield decrease (Table 1, entries 19 and 20). We also examined other
solvents involing 1,4-dioxane, THF, toluene and DMF. Each of these solvents was less
effective than MeCN (Table 1, entries 21-24). Finally, we found that the reaction was able to
reach completion in 6 h, achieving the product in 99% NMR yield and 93% isolated yield
(Table 1, entry 25).
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Table 1. Optimization of Reaction Conditionsa
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Entry [Ni] (mol %)
Base (equiv)
Solvent
Yield (%)b
1
NiCl2(dppp) (10)
NiCl2(dppf) (10)
NiCl2(dppe) (10)
NiCl2(PPh3)2 (10)
NiCl2(PCy3)2 (10)
NiCl2(dppf) (10)
NiCl2(dppf) (10)
NiCl2(dppf) (10)
NiCl2(dppf) (10)
NiCl2(dppf) (10)
NiCl2(dppf) (10)
NiCl2(dppf) (10)
NiCl2(dppf) (10)
Ni(cod)2 (10), dppf (10)
Ni(cod)2 (10)
K2CO3 (1.5)
K2CO3 (1.5)
K2CO3 (1.5)
K2CO3 (1.5)
K2CO3 (1.5)
NaOtBu (1.5)
KOtBu (1.5)
DIPEA (1.5)
Na2CO3 (1.5)
K3PO4 (1.5)
Cs2CO3 (1.5)
Cs2CO3 (1.2)
Cs2CO3 (1.0)
Cs2CO3 (1.2)
Cs2CO3 (1.2)
Cs2CO3 (1.2)
Cs2CO3 (1.2)
Cs2CO3 (1.2)
Cs2CO3 (1.2)
Cs2CO3 (1.2)
Cs2CO3 (1.2)
Cs2CO3 (1.2)
Cs2CO3 (1.2)
Cs2CO3 (1.2)
Cs2CO3 (1.2)
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
63
88
78
84
76
<2
<2
75
86
96
99
99
84
99
70
0
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18
19c
20d
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22
23
24
25e

dppf (10)
0
NiCl2(dppf) (5)
NiCl2(dppf) (10)
NiCl2(dppf) (10)
NiCl2(dppf) (10)
NiCl2(dppf) (10)
NiCl2(dppf) (10)
NiCl2(dppf) (10)
NiCl2(dppf) (10)
94
82
60
1,4-dioxane 77
THF
77
toluene
DMF
23
trace
99 (93f)
MeCN
a Unless otherwise specified, the reactions were carried out on a 0.2 mmol scale according to
b
the conditions indicated by the above equation; 0.3 mmol HP(O)Ph2 was employed. NMR
c
d
e
yield. The reaction temperature was 80 °C. The reaction temperature was 60 °C. The
reaction time was 6 h. f Isolated yield.
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With the optimized conditions in hand, we tested reaction of 1-naphthyltrimethyl-
ammonium triflate (1a) with various phosphorus-based nucleophiles (Table 2).
Diarylphosphine oxides exhibited good reactivity. Their reaction with 1a produced
1-naphthyldiarylphosphine oxides in good to excellent yields. Among the nucleophiles
diarylphosphine oxides with electron-rich substituents such as OMe and Me on the aromatic
rings led to better results than those with electron-poor groups such as F and CF3 (Table 2,
3b-3f). Dibutylphosphine oxide showed low reactivity under current reaction conditions. Its
reaction with 1a gave the desired product in only 11% yield (Table 2, 3g). Some ammonium
salt remained. Meanwhile, we observed formation of N,N-dimethylnaphthalen-1-amine via
demethylation of the ammonium salt. The low reactivity of dibutylphosphine oxide was also
seen in the nickel-catalyzed P–H/C–CN cross coupling reactions.12b Dialkyl phosphonates
were also demonstrated to react with 1a. Reactivity of the dialkyl phosphonates was
markedly under the influence of the alkyl groups. Reaction of dimethyl phosphonate, diethyl
phosphonate and dibutyl phosphonate gave good to excellent product yields. However,
reaction of diisopropyl phosphonate resulted in much lower product yield (Table 2, 3h-3k).
This might be because of steric hindrance of the isopropyl groups. Reaction of ethyl
phenylphosphinate was also tested and resulted in ethyl 1-naphthyl(phenyl)phosphinate in 79%
yield (Table 2, 3l).
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Table 2. Reaction of 1-naphthyltrimethylammonium triflate with various
phosphorous-based nucleophilesa
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a Unless otherwise specified, the reactions were carried out on a 0.2 mmol scale according to
b
the conditions indicated by the above equation; isolated yields were reported. 1.0 equiv of
base and 1.0 equiv of phosphorus nucleophile were used. c 1.5 equiv of base and 1.5 equiv of
phosphorus nucleophile were used.
Furthermore, we examined the scope of ammonium salts (Table 3). Interestingly, for the
substrates of aryltrimethylammonium triflates, only π-extended arylammonium salts were
shown to be suitable coupling partners in the reaction. Phenyltrimethylammonium triflate and
substituted phenyltrimethylammonium triflates were almost fully converted to the
corresponding N,N-dimethylphenylamine derivatives under current reaction conditions.
Reaction of N,N-dimethyl-N-phenyl-1-naphthylammonium triflate with Ph2P(O)H gave 3a in
91% yield along with N,N-dimethylaniline in 74% yield (Table 3, 3a). This further proves
that the naphthyl C-N bond is easier to break than the phenyl C-N bond. Both methoxy and
cyanide-substituted 1-naphthyltrimethylammonium triflates and 2-naphthyltrimethyl-
ammonium triflate showed good reactivity. Their reaction gave the desired products in high
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yields (Table 3, 3m-3o). Other π-extended aromatic ammonium salts such as
2-anthryltrimethylammonium triflate and 4-pyrenyltrimethylammonium triflate exhibited a
similar reactivity to the naphthyl-based ammonium salts. Unlike phenyltrimethylammonium
salt, 2-pyridyltrimethylammonium triflate as a non-extended arylammonium salt showed
good reactivity. Its reaction with 2a afforded diphenyl(2-pyridyl)phosphine oxide (3r) in 89%
yield. A series of benzyltrimethylammonium salts were also demonstrated to be suitable
electrophilic substrates. Their reaction required a longer time to reach completion. Various
(para- and ortho-substituted benzyl)trimethylammonium triflates were tested and the
reactions gave the corresponding (para- and ortho-substituted benzyl)diphenylphosphine
oxides in moderate to good yields in most cases (Table 3, 4a-4i). However, when the
substituted groups were p-Cl and o-C(O)tBu groups the reaction gave poor product yields (4e
and 4i, respectively). Reaction of the former led to unidentified by-products and reaction of
the latter was incomplete due to steric hindrance of the C(O)tBu group. Other groups such as
MeO, CF3, F, C(O)NMe2, and CN groups can be tolerated. Both (1-naphthylmethyl)
trimethylammonium triflate and (4-methoxy-1-naphthylmethyl)trimethylammonium triflate
showed comparable reactivity to benzyltrimethylammonium triflate and (4-methoxyphenyl-
methyl)trimethylammonium triflate (Table 3, 4j and 4k). Whereas (2-naphthylmethyl)
trimethylammonium triflate and (6-methoxy-2-naphthylmethyl)trimethylammonium triflate
exhibited markedly higher reactivity than the 1-naphthylmethylammonium salts for unclear
reason (Table 3, 4l and 4m). We also demonstrated that secondary benzylic ammonium salts
were not suitable substrates for this coupling reaction. Reaction of
[(1R)-1-phenylethyl]trimethylammonium triflate with HP(O)Ph2 under the same conditions
resulted in only trace amount of product. In addition, allyltrimethylammonium triflate was
found to have excellent reactivity. Its reaction with HP(O)Ph2 under the standard conditions
gave the cross-coupling product in 98% yield. The 1H NMR spectral analysis showed that the
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product
was
a
mixture
of
allyldiphenylphosphine
oxide
and
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(E)-diphenyl(prop-1-en-1-yl)phosphine oxide in 87 to 13 ratio. The latter was thought to form
via the isomerization of the former. If the reaction was run at 80 °C, the isomerization can be
avoided and 94% yield of allyldiphenylphosphine oxide was achieved (Table 3, 5).
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Table 3. Scope of the ammonium saltsa
NiCl2(dppf) (10 mol%)
+
HP(O)Ph2
R NMe3OTf
R P(O)Ph2
Cs2CO3 (1.2 equiv)
MeCN (2 mL)
100 °C, 6 h
3-5
1
2a
R = aryl, benzyl, allyl
Ph
NMe2OTf
MeO
CN
3a, 91% (74%b)
3m, 99%
3n
, 85%
3o, 84%
3p, 82%
3q, 99%c
4a, R = H, 64%d
4b, R = OMe, 54%d
4c, R = CF3, 40%d
4d, R = F, 59%d
N
R
4e, R = Cl, 21%d
3r, 89%
4f, R = CONMe2, 85%d
4g, R = CN, 50%d
R
4h, R = F, 74%d
4i, R = COtBu, 21%d
R
R
5, 94%d,e
4l, R = H, 85%
4m, R = OMe, 88%
4j, R = H, 58%
4k, R = OMe, 50%
a Unless otherwise specified, the reactions were carried out on a 0.2 mmol scale according to
b
the conditions indicated by the above equation; isolated yields were reported. By-product:
c
d
N,N-dimethylaniline. 1.5 equiv of Cs2CO3 and 1.5 equiv of 2a were used. The reaction
time was 18 h. e The reaction was run at 80 °C.
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We also examined reaction of benzylammonium salts in the presence of other counter
anions including OTs, OMs, I, Br and Cl (Scheme 1). The result showed that the counter
anions play a relatively small role in the reaction. The reaction gave comparable yields when
OMs, Br or Cl was employed to replace OTf as the counter anion. When OTs and I
were employed as the counter anions a little lower yields were achieved. Those facts further
shows wide substrate applicability of this protocol from the angle of counterions.
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Scheme 1. Counterion effect in the reaction of benzylammonium salts with HP(O)Ph2
To demonstrate the utility of the protocol, we performed the reaction by employing a larger
scale of reactants. Thus, 2 mmol of 1-naphthyltrimethylammonium triflate was reacted with
1.2 equiv of HP(O)Ph2 under the standard conditions to afford the desired product in 87%
yield (Scheme 2a). 1-Naphthyltrimethylammonium triflate can also be prepared in situ by
reaction of N,N-dimethylnaphthalen-1-amine with MeOTf. Reaction of the in situ-formed
ammonium salt with HP(O)Ph2 gave the product in 88% overall yield (Scheme 2b). Similarly,
reaction of in situ-prepared benzyltrimethylammonium triflate with HP(O)Ph2 on 2 mmol
scale resulted in the desired product in 61% yield (Scheme 2c).
Scheme
2.
Reaction
of
1-naphthyltrimethylammonium
triflate
or
benzyltrimethylammonium triflate with HP(O)Ph2 on 2 mmol scale
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Preliminary experiments to evaluate the plausible reaction mechanism were performed. In
the absence of
a
nickel catalyst the reaction of HP(O)Ph2 with either
1-naphthyltrimethylammonium triflate or (2-naphthylmethyl)trimethylammonium triflate
cannot occur, which rules out the possibility of a direct nucleophilic substitution.
Ni(cod)2/dppf system exhibited almost the same catalytic activity as NiCl2(dppf) (Table 1,
entry 14). The reaction of HP(O)Ph2 with either 1-naphthyltrimethylammonium triflate or
(2-naphthylmethyl)trimethylammonium triflate in the presence of stoichiometric
Ni(cod)2/dppf gave also excellent product yields (Scheme 3a). These experimental facts
imply that the reaction might proceed via a Ni(0)/Ni(II) process. In an earlier study, Watson et
al. isolated complex 6 via reaction of (2-pivaloylphenylmethyl)trimethylammonium triflate
with Ni(cod)2/PPh2Cy.17d That we attempted to isolate similar intermediate via reaction of
(2-pivaloylphenylmethyl)trimethylammonium triflate with Ni(cod)2/dppf was unsuccessful.
However, we found that Ni(cod)2/PPh2Cy was able to catalyze the coupling of HP(O)Ph2
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with either 1-naphthyltrimethylammonium triflate or (2-naphthylmethyl)trimethyl ammonium
triflate (Scheme 3b). Hence in our research a similar reaction intermediate was still believed
to form during the reaction process. We demonstrated that reaction of complex 6 with 1.2
equiv of HP(O)Ph2 in the presence of 1 equiv of dppf and 1.2 equiv of Cs2CO3 in MeCN
afforded the corresponding coupling product in 56% yield (Scheme 3c). Complex 6 also
catalyzed the coupling reaction of 1-naphthyltrimethylammonium triflate or
(2-naphthylmethyl)trimethyl ammonium triflate with HP(O)Ph2 (Scheme 3d). On the basis of
the above experimental facts and the reported results in the literature,5e,11,12b a plausible
catalytic cycle is outlined in Scheme 4. Thus, the Ni(II) complex is reduced to Ni(0) species
A by the phosphorus compounds.4d Oxidative addition of the Ni(0) species with an
ammonium salt results in intermediate B along with release of NMe3. Subsequently, the
ligand exchange of B with CsOPPh2 generated from the reaction of HP(O)R1R2 with Cs2CO3
forms intermediate C, which undergoes reductive elimination to give product R-P(O)R1R2
along with regeneration of Ni(0) complex A.
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Scheme 3. Mechanistic studies
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(a)
NMe3OTf
P(O)Ph2
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8
9
H(O)PPh2 (1.2 equiv)
Ni(COD)2 (1.0 equiv)
4l, 87%
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P(O)Ph2
dppf (1.0 equiv)
or
NMe3OTf
or
Cs2CO3 (1.2 equiv)
MeCN, 100 °C
3a, 92%
(b)
P(O)Ph2
NMe3OTf
H(O)PPh2 (1.2 equiv)
Ni(COD)2 (10 mol %)
PPh2Cy (20 mol %)
4l, 66%
P(O)Ph2
NMe3OTf
or
or
Cs2CO3 (1.2 equiv)
MeCN, 100 °C
3a, 79%
(c)
PPh2Cy
H(O)PPh2 (1.2 equiv)
dppf (1.0 equiv)
Ni OTf
O
P(O)Ph2
O
Cs2CO3 (1.2 equiv)
MeCN, 100 °C
tBu
6
tBu
4i, 56%
(d)
NMe3OTf
NMe3OTf
P(O)Ph2
H(O)PPh2
6 (10 mol %)
PPh2Cy (10 mol %)
4l, 61%
P(O)Ph2
Cs2CO3 (1.2 equiv)
MeCN, 100 °C
or
or
3a, 70%
Scheme 4. Proposed catalytic cycle
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Conclusions
We developed a method of constructing C-P bonds via nickel-catalyzed cross-coupling of
aryl-, benzyl- and allyl-ammonium triflates with phosphorus-based nucleophiles including
diaryl/dibutyl phosphine oxide, dialkyl phosphonates, and ethyl phenylphosphinate. Through
the reaction a series of phosphonylation products of the ammonium salts were synthesized in
reasonable to excellent yields in most cases. The method suits for a wide scope of substrates
and tolerates a range of functional groups such as OMe, CN, CF3, F, Cl, C(O)NMe2, and
C(O)tBu. We believe that this study would provide a valuable complement to the construction
of C-P bonds in organic synthesis.
Experimental section
All reactions were performed under nitrogen atmosphere using standard Schlenk and vacuum
line techniques. All chemicals were purchased as reagent grade and used without further
purification unless otherwise noted. Toluene and tetrahydrofuran were purified by JC Meyer
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Phoenix Solvent Systems. 1,4-Dioxane and cyclohexane were distilled under nitrogen over
sodium and degassed prior to use. DMF was dried over 4 Å molecular sieves, fractionally
distilled under reduced pressure, and stored under nitrogen atmosphere. MeCN was dried
over 4 Å molecular sieve, then fractionally distilled, and stored under nitrogen atmosphere.
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PhCH2NMe3 Cl–, PhCH2NMe3 Br–, and PhCH2NMe3 I– were purchased from Innochem,
Ark, and Alpha Chemicals, respectively. The known ammonium triflates were prepared
according to the reported procedure.17d,17g,19 HP(O)(OR)2 (R = Me, Et, iPr, nBu) and
HP(O)(OEt)Ph were purchased from commercial vendors. HP(O)R2 (R = Ph, p-MeOC6H4,
p-MeC6H4, p-FC6H4, 3,5-Me2C6H3, nBu) were prepared according to the literature
procedures.20 NMR spectra were recorded on a Bruker av400 spectrometer at ambient
1
temperature. The chemical shifts of the H NMR spectra were referenced to TMS and the
chemical shifts of the C{1H} NMR spectra were referenced to internal solvent resonances.
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The chemical shifts of 19F{1H} NMR spectra were referenced to external trifluoroacetic acid
and the chemical shifts of 31P{1H} NMR spectra were referenced to external phosphoric acid.
High-resolution mass spectra (HRMS) were acquired in the ESI mode using an Orbitrap mass
analyzer.
Preparation of 5-cyano-N,N,N-trimethylnaphthalen-1-ammonium triflate. To a Schlenk
tube was charged 5-(dimethylamino)-1-naphthonitrile (0.73 g, 3.7 mmol) and CH2Cl2 (7 mL)
under nitrogen. MeOTf (0.84 mL, 7.4 mmol) was added dropwise to the stirred solution at
0 °C. The resultant solution was allowed to warm to room temperature and stirred overnight.
Volatiles were removed in vacuum. The residual solid was washed with Et2O (3  10 mL),
and dried under vacuum to give the ammonium triflates (1.27 g, 95%) as a light green solid.
1H NMR (400 MHz, DMSO-d6): δ 9.04 (d, J = 8.8 Hz, 1H), 8.43–8.31 (m, 3H), 8.01–7.89
(m, 2H), 3.95 (s, 9H). C{1H} NMR (101 MHz, DMSO-d6): δ 142.2, 134.0, 133.8, 128.9,
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128.5, 128.2, 127.6, 123.9, 122.3, 120.7 (q, J = 323.3 Hz), 117.2, 111.4, 57.6. 19F NMR (376
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MHz, DMSO-d6): δ –77.8. HRMS (ESI-TOF) m/z: [M-OTf]+ Calcd for C14H15N2 211.1230;
Found 211.1228.
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General procedure for the preparation of other ammonium triflates. To a Schlenk tube
was charged aryl- (or arylmethyl)dimethylamine and Et2O. To the stirred solution was added
dropwise MeOTf (1.2 equiv) at 0 °C. A precipitate formed immediately. After complete
addition, the mixture was stirred at 0 °C for 15 min and then at room temperature for 2 h. The
precipitate was collected by filtration and washed with Et2O for 3 times. The resulting solid
was dried under vacuum to give the ammonium triflates.
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N,N-Dimethyl-N-phenylnaphthalen-1-ammonium triflate. Blue solid (89%). H NMR (400
MHz, DMSO-d6): δ 8.43 (d, J = 7.9 Hz, 1H), 8.30 (d, J = 8.2 Hz, 1H), 8.15 (d, J = 8.1 Hz,
1H), 7.83 (t, J = 8.1 Hz, 1H), 7.69 (d, J = 7.3 Hz, 2H), 7.63–7.51 (m, 4H), 7.45–7.38 (m, 1H),
7.26 (d, J = 8.8 Hz, 1H), 4.25 (s, 6H). 13C{1H} NMR (101 MHz, DMSO-d6): δ 148.7, 141.3,
135.4, 132.6, 130.6, 130.2, 130.1, 127.9, 126.6, 125.0, 123.6, 122.8, 121.0, 120.7 (q, J =
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322.2 Hz), 120.6, 58.7. F NMR (376 MHz, DMSO-d6): δ –77.7. HRMS (ESI-TOF) m/z:
[M-OTf]+ Calcd for C18H18N 248.1434; Found 248.1425.
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N,N,N-Trimethylpyren-4-ammonium triflate. White solid (93%). H NMR (400 MHz,
DMSO-d6): δ 8.92 (d, J = 9.6 Hz, 1H), 8.65 (d, J = 8.9 Hz, 1H), 8.58–8.47 (m, 4H), 8.39 (d,
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J = 8.9 Hz, 1H), 8.32 (d, J = 9.0 Hz, 1H), 8.25 (t, J = 7.7 Hz, 1H), 4.09 (s, 9H). C{1H}
NMR (101 MHz, DMSO-d6): δ 138.8, 132.4, 130.6, 129.7, 129.4, 129.0, 127.39, 127.37,
126.8, 126.7, 125.5, 125.1, 123.5, 122.2, 121.6, 120.8 (q, J = 322.2 Hz), 119.2, 57.8. 19F
NMR (376 MHz, DMSO-d6): δ –77.8. HRMS (ESI-TOF) m/z: [M-OTf]+ Calcd for C19H18N
260.1434; Found 260.1429.
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7-Methoxy-N,N,N-trimethylnaphthalen-1-ammonium triflate. White solid (95%). H NMR
(400 MHz, DMSO-d6): δ 8.23–8.04 (m, 3H), 7.60–7.48 (m, 2H), 7.43 (d, J = 9.0 Hz, 1H),
4.05 (s, 3H), 3.92 (s, 9H). 13C{1H} NMR (101 MHz, DMSO-d6): δ 158.4, 139.9, 132.4,
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132.1, 130.8, 124.9, 122.4, 120.8, 120.7 (q, J = 322.2 Hz), 118.5, 103.1, 56.9, 55.8. 19F NMR
(376 MHz, DMSO-d6): δ –77.8. HRMS (ESI-TOF) m/z: [M-OTf]+ Calcd for C14H18ON
216.1383; Found 216.1376.
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1-(4-Chlorophenyl)-N,N,N-trimethylmethanammonium triflate. White solid (95%). H NMR
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(400 MHz, DMSO-d6) δ 7.65–7.49 (m, 4H), 4.53 (s, 2H), 3.03 (s, 9H). C{1H} NMR (101
MHz, DMSO-d6): δ 135.4, 134.6, 129.1, 127.3, 120.7 (q, J = 322.1 Hz), 66.9, 51.8. 19F NMR
(376 MHz, DMSO-d6): δ –77.8. HRMS (ESI-TOF) m/z: [M-OTf]+ Calcd for C10H15NCl
184.0888; Found 184.0884.
1-(4-(Dimethylcarbamoyl)phenyl)-N,N,N-trimethylmethanammonium triflate. White solid
(96%). 1H NMR (400 MHz, DMSO-d6): δ 7.59 (d, J = 8.1 Hz, 2H), 7.52 (d, J = 8.1 Hz, 2H),
4.55 (s, 2H), 3.05 (s, 9H), 2.99 (s, 3H), 2.90 (s, 3H). 13C{1H} NMR (101 MHz, DMSO-d6): δ
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169.4, 138.3, 132.8, 129.2, 127.4, 120.7 (q, J = 322.1 Hz), 67.4, 51.8, 34.7. F NMR (376
MHz, DMSO-d6): δ –77.8. HRMS (ESI-TOF) m/z: [M-OTf]+ Calcd for C13H21ON2 221.1648;
Found 221.1641.
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1-(2-Fluorophenyl)-N,N,N-trimethylmethanammonium triflate. White solid (97%). H NMR
(400 MHz, DMSO-d6): δ 7.68–7.56 (m, 2H), 7.44–7.31 (m, 2H), 4.60 (s, 2H), 3.08 (s, 9H).
13C{1H} NMR (101 MHz, DMSO-d6): δ 161.6 (d, J = 249.3 Hz), 135.2 (d, J = 2.4 Hz), 133.3
(d, J = 8.8 Hz), 125.1 (d, J = 3.4 Hz), 120.7 (q, J = 322.1 Hz), 116.3 (d, J = 21.9 Hz), 115.6
(d, J = 14.3 Hz), 61.6, 52.0. 19F NMR (376 MHz, DMSO-d6): δ –77.8, –112.8. HRMS
(ESI-TOF) m/z: [M-OTf]+ Calcd for C10H15NF 168.1183; Found 168.1177.
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N,N,N-Trimethyl-1-(naphthalen-1-yl)methanammonium triflate. White solid (96%). H NMR
(400 MHz, DMSO-d6): δ 8.50 (d, J = 8.5 Hz, 1H), 8.14 (d, J = 8.2 Hz, 1H), 8.05 (d, J = 8.0
Hz, 1H), 7.80 (d, J = 6.8 Hz, 1H), 7.72–7.57 (m, 3H), 5.06 (s, 2H), 3.11 (s, 9H). C{1H}
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NMR (101 MHz, DMSO-d6): δ 133.7, 133.6, 132.8, 131.4, 129.1, 127.4, 126.3, 125.3, 124.5,
124.0, 120.7 (q, J = 323.3 Hz), 63.9, 52.3. 19F NMR (376 MHz, DMSO-d6): δ –77.7. HRMS
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(ESI-TOF) m/z: [M-OTf]+ Calcd for C14H18N 200.1434; Found 200.1429.
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1-(4-Methoxynaphthalen-1-yl)-N,N,N-trimethylmethanammonium triflate. White solid (94%).
1H NMR (400 MHz, DMSO-d6): δ 8.42 (d, J = 8.6 Hz, 1H), 8.28 (d, J = 8.4 Hz, 1H), 7.73 (d,
J = 8.1 Hz, 1H), 7.69 (t, J = 7.8 Hz, 1H), 7.63–7.53 (m, 1H), 7.13 (d, J = 8.1 Hz, 1H), 4.97 (s,
2H), 4.03 (s, 3H), 3.07 (s, 9H). 13C{1H} NMR (101 MHz, DMSO-d6): δ 156.8, 134.6, 133.7,
127.7, 125.6, 125.2, 124.0, 122.3, 120.7 (q, J = 323.2 Hz), 116.3, 104.0, 64.1, 55.9, 51.9. 19F
NMR (376 MHz, DMSO-d6): δ –77.8. HRMS (ESI-TOF) m/z: [M-OTf]+ Calcd for
C15H20ON 230.1539; Found 230.1531.
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1-(6-Methoxynaphthalen-2-yl)-N,N,N-trimethylmethanammonium triflate. White solid (92%).
1H NMR (400 MHz, CDCl3): δ 7.88 (s, 1H), 7.72 (d, J = 9.0 Hz, 1H), 7.69 (d, J = 8.5 Hz,
1H), 7.45 (dd, J = 8.4, 1.7 Hz, 1H), 7.15 (dd, J = 9.0, 2.5 Hz, 1H), 7.05 (d, J = 2.4 Hz, 1H),
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4.71 (s, 2H), 3.91 (s, 3H), 3.17 (s, 9H). C{1H} NMR (101 MHz, CDCl3): δ 159.2, 135.5,
133.3, 130.1, 129.3, 128.4, 128.0, 121.9, 120.9 (q, J = 321.0 Hz), 120.2, 105.6, 69.9, 55.5,
52.6. 19F NMR (376 MHz, CDCl3): δ –78.3. HRMS (ESI-TOF) m/z: [M-OTf]+ Calcd for
C15H20ON 230.1539; Found 230.1538.
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N,N,N-Trimethylprop-2-en-1-ammonium triflate. White solid (97%). H NMR (400 MHz,
DMSO-d6): δ 6.12–5.96 (m, 1H), 5.68–5.55 (m, 2H), 3.94 (d, J = 7.3 Hz, 2H), 3.02 (s, 9H).
13C{1H} NMR (101 MHz, DMSO-d6): δ 127.7, 126.0, 120.7 (q, J = 321.7 Hz), 67.4–67.0 (m),
51.9 (d, J = 3.8 Hz). 19F NMR (376 MHz, DMSO-d6): δ –77.9. HRMS (ESI-TOF) m/z:
[M-OTf]+ Calcd for C6H14N 100.1121; Found 100.1117.
Preparation of benzyltrimethylammonium 4-methylbenzenesulfonate. To a Schlenk tube
was charged N,N-dimethyl-1-phenylmethanamine (0.9 mL, 6.0 mmol) and Et2O (10 mL)
under nitrogen. MeOTs (1.1 mL, 7.2 mmol) was added dropwise to the stirred solution at
0 °C. The resultant mixture was allowed to warm to room temperature and stirred for 24 h.
Volatiles were removed in vacuo. The residual solid was washed with Et2O (3  10 mL), and
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then dried under vacuum to give benzyltrimethylammonium 4-methylbenzenesulfonate as a
white solid (1.8 g, 96%). 1H NMR (400 MHz, CDCl3): δ 7.76 (d, J = 8.0 Hz, 2H), 7.50–7.43
(m, 2H), 7.42–7.35 (m, 1H), 7.34–7.27 (m, 2H), 7.12 (d, J = 8.0 Hz, 2H), 4.71 (s, 2H), 3.18 (s,
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9H), 2.31 (s, 3H). C NMR (101 MHz, CDCl3): δ 144.0, 139.5, 133.1, 130.4, 129.0, 128.8,
127.8, 125.8, 68.7, 52.2, 21.3.. HRMS (ESI-TOF) m/z: [M-OTs]+ Calcd for C10H16N
150.1277; Found 150.1275.
Preparation of benzyltrimethylammonium methanesulfonate. The same procedure as for
the preparation of benzyltrimethylammonium 4-methylbenzenesulfonate was employed but
MeOMs (0.6 mL, 7.2 mmol) was used to replace MeOTs. After workup,
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benzyltrimethylammonium methanesulfonate was obtained as a white solid (1.1 g, 75%). H
NMR (400 MHz, DMSO-d6): δ 7.64–7.44 (m, 5H), 4.55 (s, 2H), 3.03 (s, 9H), 2.33 (s, 3H).
13C NMR (101 MHz, DMSO-d6): δ 132.9, 130.3, 128.9, 128.5, 67.6, 51.7, 39.8. HRMS
(ESI-TOF) m/z: [M-OMs]+ Calcd for C10H16N150.1277; Found 150.1272.
General Procedure for the Ni-catalyzed cross-coupling of the ammonium triflates with
phosphorus-based nucleophiles. Ammonium salts (0.2 mmol), P-sources (0.2 or 0.3 mmol
depending on the substrates), NiCl2(dppf) (10 mol%), Cs2CO3 (0.2 or 0.3 mmol depending on
the substrates) and MeCN (2 mL) were charged to a dry Schlenk tube under nitrogen. The
mixture was stirred at room temperature for 5 min and then stirred at 100 °C for 6 h or 18 h
depending on the reaction. The mixture was diluted with CH3COOEt (5 mL) and filtered
through a plug of silica gel, which was rinsed with CH3COOEt (20 mL). The filtrate was
concentrated and then purified by column chromatography on silica gel to give the desired
products.
In situ preparation of 1-naphthyltrimethylammonium triflate and its reaction with
HP(O)Ph2 on a submillimolar scale. N,N-Dimethylnaphthalen-1-amine (0.33 mL, 2 mmol)
and Et2O (5 mL) were added to a Schlenk tube under nitrogen. To the stirred solution MeOTf
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(0.27 mL, 2.4 mmol) was added dropwise at 0 °C. The resultant solution was stired at 0 °C
for 15 min and then at room temperature for 2 h. Volatiles were removed in vacuo. HP(O)Ph2
(485 mg, 2.4 mmol), NiCl2(dppf) (137 mg, 0.2 mmol), Cs2CO3 (782 mg, 2.4 mmol) and
MeCN (8 mL) were successively added to the Schlenk tube under nitrogen. The mixture was
stirred at room temperature for 5 min and then at 100 °C for 6 h. The resultant mixture was
cooled to room temperature, diluted with CH3COOEt (10 mL) and filtered through a plug of
silica gel which was rinsed with CH3COOEt (40 mL). The filtrate was concentrated and then
purified by column chromatography on silica gel (elution with petroleum ether/ethyl acetate
1:1 (v/v)) to give naphthalen-1-yldiphenylphosphine oxide as a white solid (580 mg, 88%).
Naphthalen-1-yldiphenylphosphine oxide (3a).5e Elution with petroleum ether/ethyl acetate
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1:1 (v/v), white solid (61.3 mg, 93%). H NMR (400 MHz, CDCl3): δ 8.59 (d, J = 8.4 Hz,
1H), 8.00 (d, J = 8.1 Hz, 1H), 7.88 (d, J = 8.1 Hz, 1H), 7.75–7.63 (m, 4H), 7.57–7.51 (m, 2H),
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7.51–7.40 (m, 6H), 7.37 (dt, J = 7.2, 2.8 Hz, 1H), 7.33–7.27 (m, 1H). C{1H} NMR (101
MHz, CDCl3): δ 133.9, 133.86 (d, J = 26.9 Hz), 133.8 (d, J = 2.1 Hz), 133.4 (d, J = 2.4 Hz),
132.3, 132.1 (d, J = 9.8 Hz), 132.0 (d, J = 2.8 Hz), 129.0 (d, J = 102.1 Hz), 128.9 (d, J = 1.1
Hz), 128.7 (d, J = 12.2 Hz), 127.7 (d, J = 5.8 Hz), 127.4, 126.6, 124.2 (d, J = 14.3 Hz).
31P{1H} NMR (162 MHz, CDCl3): δ 32.4.
Bis(4-methoxyphenyl)(naphthalen-1-yl)phosphine oxide (3b). Elution with petroleum
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ether/ethyl acetate 1:1 (v/v), colorless oil (66.1 mg, 85%). H NMR (400 MHz, CDCl3): δ
8.59 (d, J = 8.4 Hz, 1H), 7.98 (d, J = 8.1 Hz, 1H), 7.87 (d, J = 8.1 Hz, 1H), 7.59 (d, J = 8.8
Hz, 2H), 7.56 (d, J = 8.8 Hz, 2H), 7.51–7.39 (m, 2H), 7.39–7.33 (m, 1H), 7.32–7.25 (m, 1H),
6.94 (dd, J = 8.9, 2.2 Hz, 4H), 3.82 (s, 6H). 13C{1H} NMR (101 MHz, CDCl3): δ 162.4 (d, J
= 2.8 Hz), 133.9 (d, J = 11.1 Hz), 133.8, 133.7 (d, J = 2.4 Hz), 133.1 (d, J = 2.8 Hz), 129.7 (d,
J = 102.7 Hz), 128.8, 127.8 (d, J = 5.8 Hz), 127.3, 126.5, 124.8, 124.2 (d, J = 14.3 Hz), 123.7,
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114.2 (d, J = 13.2 Hz), 55.4. P{1H} NMR (162 MHz, CDCl3): δ 32.3. HRMS (ESI-TOF)
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m/z: [M + Na]+ Calcd for C24H21O3NaP 411.1121; Found 411.1105.
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Naphthalen-1-yldi-p-tolylphosphine oxide (3c). Elution with petroleum ether/ethyl acetate 1:1
(v/v), white solid (69.0 mg, 97%), mp 159-161 °C. 1H NMR (400 MHz, CDCl3): δ 8.62 (d, J
= 8.3 Hz, 1H), 7.96 (d, J = 7.7 Hz, 1H), 7.84 (d, J = 7.9 Hz, 1H), 7.58 (d, J = 8.0 Hz, 2H),
7.55 (d, J = 8.0 Hz, 2H), 7.49–7.37 (m, 2H), 7.37–7.26 (m, 2H), 7.23 (dd, J = 8.1, 2.4 Hz,
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4H), 2.36 (s, 6H). C{1H} NMR (101 MHz, CDCl3): δ 142.2 (d, J = 2.8 Hz), 133.8 (d, J =
8.9 Hz), 133.7 (d, J = 8.1 Hz), 133.6 (d, J = 11.7 Hz), 133.1 (d, J = 2.8 Hz), 132.0 (d, J =
10.2 Hz), 129.7 (d, J = 106.8 Hz), 129.4 (d, J = 101.9 Hz), 129.3 (d, J = 12.6 Hz), 128.7 (d, J
= 0.9 Hz), 127.7 (d, J = 5.8 Hz), 127.2, 126.4, 124.1 (d, J = 14.2 Hz), 21.6 (d, J = 1.1 Hz).
31P{1H} NMR (162 MHz, CDCl3): δ 32.6. HRMS (ESI-TOF) m/z: [M + Na]+ Calcd for
C24H21ONaP 379.1222; Found 379.1209.
Bis(4-fluorophenyl)(naphthalen-1-yl)phosphine oxide (3d). Elution with petroleum
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ether/ethyl acetate 1:1 (v/v), white solid (51.2 mg, 70%), mp 153-155 °C. H NMR (400
MHz, CDCl3): δ 8.53 (d, J = 8.4 Hz, 1H), 8.04 (d, J = 8.2 Hz, 1H), 7.90 (d, J = 8.1 Hz, 1H),
7.73–7.61 (m, 4H), 7.52 (t, J = 7.1 Hz, 1H), 7.49–7.43 (m, 1H), 7.40 (dt, J = 7.4, 2.4 Hz, 1H),
7.31–7.23 (m, 1H), 7.17 (dt, J = 8.6, 2.0 Hz, 4H). 13C{1H} NMR (101 MHz, CDCl3): δ 165.2
(dd, J = 254.8, 3.2 Hz), 134.6 (dd, J = 11.3, 8.8 Hz), 134.0 (d, J = 9.1 Hz), 133.8 (d, J = 6.7
Hz), 133.7 (d, J = 2.2 Hz), 133.6 (d, J = 8.4 Hz), 129.2 (d, J = 3.4 Hz), 129.0 (d, J = 0.9 Hz),
128.4 (d, J = 104.1 Hz), 128.1 (d, J = 3.4 Hz), 127.4 (d, J = 5.8 Hz), 127.2 (d, J = 88.8 Hz),
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124.3 (d, J = 14.5 Hz), 116.2 (dd, J = 21.4, 13.4 Hz). F{1H} NMR (376 MHz, CDCl3): δ
31
106.35, 106.36. P{1H} NMR (162 MHz, CDCl3): δ 31.0. HRMS (ESI-TOF) m/z: [M +
Na]+ Calcd for C22H15OF2NaP 387.0721; Found 387.0707.
Naphthalen-1-ylbis(4-(trifluoromethyl)phenyl)phosphine oxide (3e). Elution with petroleum
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ether/ethyl acetate 1:1 (v/v), colorless oil (35.3 mg, 38%). H NMR (400 MHz, CDCl3): δ
8.48 (d, J = 8.4 Hz, 1H), 8.09 (d, J = 8.2 Hz, 1H), 7.94 (d, J = 8.1 Hz, 1H), 7.88–7.79 (m, 4H),
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7.78–7.70 (m, 4H), 7.55 (t, J = 7.5 Hz, 1H), 7.52–7.47 (m, 1H), 7.44 (dt, J = 2.7, 7.8 Hz, 1H),
7.33–7.24 (m, 1H). 13C NMR (101 MHz, CDCl3): 137.2, 136.2, 134.4, 134.34, 134.31, 134.1
(d, J = 9.3 Hz), 134.05, 134.02, 133.9 (d, J = 12.1 Hz), 133.5 (d, J = 8.6 Hz), 132.7 (d, J =
10.2 Hz), 129.2, 127.6 (d, J = 98.8 Hz), 127.2 (d, J = 6.0 Hz), 127.1 (d, J = 105.1 Hz), 125.9
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(q, J = 3.7 Hz), 125.7 (q, J = 3.7 Hz), 123.6 (q, J = 273.4 Hz). F{1H} NMR (376 MHz,
CDCl3): δ –63.19. 31P{1H} NMR (162 MHz, CDCl3): δ 30.17. HRMS (ESI-TOF) m/z:
[M+H]+ Calcd for C24H16OF6P 465.0838; Found 465.0830.
Bis(3,5-dimethylphenyl)(naphthalen-1-yl)phosphine oxide (3f). Elution with petroleum
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ether/ethyl acetate 1:1 (v/v), white solid (74.7 mg, 97%), mp 181-183 °C. H NMR (400
MHz, CDCl3): δ 8.61 (d, J = 8.3 Hz, 1H), 7.98 (d, J = 8.1 Hz, 1H), 7.86 (d, J = 7.9 Hz, 1H),
7.50–7.40 (m, 2H), 7.40–7.34 (m, 1H), 7.34–7.25 (m, 5H), 7.15 (s, 2H), 2.29 (s, 12H).
13C{1H} NMR (101 MHz, CDCl3): δ 138.2 (d, J = 12.8 Hz), 133.89 (d, J = 15.5 Hz), 133.88
(d, J = 1.3 Hz), 133.7 (d, J = 3.0 Hz), 133.5 (d, J = 70.6 Hz), 133.1 (d, J = 2.8 Hz), 132.1,
129.6 (d, J = 9.8 Hz), 129.4 (d, J = 101.1 Hz), 128.7 (d, J = 0.9 Hz), 127.8 (d, J = 5.7 Hz),
127.3, 126.4, 124.2 (d, J = 14.3 Hz), 21.4. 31P{1H} NMR (162 MHz, CDCl3): δ 33.0. HRMS
(ESI-TOF) m/z: [M + Na]+ Calcd for C26H25ONaP 407.1535; Found 407.1520.
Dibutyl(naphthalen-1-yl)phosphine oxide (3g). Elution with petroleum ether/ethyl acetate 1:1
to 2:1 (v/v), colorless oil (6.5 mg, 11%). 1H NMR (400 MHz, CDCl3): δ 8.60 (d, J = 8.2 Hz,
1H), 8.12–7.84 (m, 3H), 7.69–7.44 (m, 3H), 2.31–2.03 (m, 4H), 1.75–1.29 (m, 8H), 0.84 (t, J
= 7.1 Hz, 6H). C{1H} NMR (101 MHz, CDCl3): δ 133.8 (d, J = 8.8 Hz), 133.3 (d, J = 8.7
13
Hz), 132.7 (d, J = 2.7 Hz), 132.3 (d, J = 8.0 Hz), 129.4, 128.8 (d, J = 87.7 Hz), 127.3, 126.3,
125.7 (d, J = 3.8 Hz), 124.8 (d, J = 12.3 Hz), 30.5 (d, J = 68.2 Hz), 24.2 (d, J = 14.8 Hz),
23.9 (d, J = 4.0 Hz), 13.7. 31P{1H} NMR (162 MHz, CDCl3): δ 42.5. HRMS (ESI-TOF) m/z:
[M + Na]+ Calcd for C18H26OP: 289.1716; Found 289.1707.
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Dimethyl naphthalen-1-ylphosphonate (3h).5c Elution with petroleum ether/ethyl acetate 1:1
(v/v), colorless oil (33.7 mg, 71%). 1H NMR (400 MHz, CDCl3): δ 8.46 (d, J = 8.4 Hz, 1H),
8.24 (ddd, J = 16.4, 7.1, 1.2 Hz, 1H), 8.06 (d, J = 8.2 Hz, 1H), 7.91 (d, J = 8.1 Hz, 1H), 7.67–
7.60 (m, 1H), 7.60–7.51 (m, 2H), 3.80 (d, J = 11.3 Hz, 6H). 13C{1H} NMR (101 MHz,
CDCl3): δ 135.1 (d, J = 9.2 Hz), 134.0 (d, J = 3.4 Hz), 133.7 (d, J = 12.8 Hz), 132.8 (d, J =
11.0 Hz), 129.0 (d, J = 1.9 Hz), 127.8 (d, J = 0.5 Hz), 126.6, 126.5 (d, J = 4.3 Hz), 124.5 (d, J
= 16.7 Hz), 123.3 (d, J = 183.7 Hz), 52.8 (d, J = 5.4 Hz). 31P{1H} NMR (162 MHz, CDCl3):
δ 22.4.
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Diethyl naphthalen-1-ylphosphonate (3i).9 Elution with petroleum ether/ethyl acetate 1:1
(v/v), colorless oil (49.6 mg, 94%). 1H NMR (400 MHz, CDCl3): δ 8.52 (d, J = 8.5 Hz, 1H),
8.26 (ddd, J = 16.3, 7.0, 1.2 Hz, 1H), 8.04 (d, J = 8.2 Hz, 1H), 7.89 (d, J = 8.1 Hz, 1H), 7.61
(ddd, J = 8.5, 6.9, 1.4 Hz, 1H), 7.58–7.49 (m, 2H), 4.28–4.02 (m, 4H), 1.31 (t, J = 7.1 Hz,
6H). 13C{1H} NMR (101 MHz, CDCl3): δ 134.8 (d, J = 9.2 Hz), 133.7 (d, J = 3.4 Hz), 133.6,
132.8 (d, J = 10.9 Hz), 128.9 (d, J = 1.8 Hz), 127.5, 126.7 (d, J = 4.2 Hz), 126.4, 124.7 (d, J
= 182.5 Hz), 124.6 (d, J = 16.6 Hz), 62.2 (d, J = 5.2 Hz), 16.4 (d, J = 6.6 Hz). 31P{1H} NMR
(162 MHz, CDCl3): δ 19.2.
Diisopropyl naphthalen-1-ylphosphonate (3j).5d Elution with petroleum ether/ethyl acetate
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1:1 (v/v), colorless oil (17.2 mg, 29%). H NMR (400 MHz, CDCl3): δ 8.53 (d, J = 8.5 Hz,
1H), 8.28 (dd, J = 16.3, 7.0 Hz, 1H), 8.02 (d, J = 8.2 Hz, 1H), 7.88 (d, J = 8.0 Hz, 1H), 7.64–
7.47 (m, 3H), 4.80–4.67 (m, 2H), 1.41 (d, J = 6.2 Hz, 6H), 1.28 (d, J = 6.2, Hz, 6H). 13C{1H}
NMR (101 MHz, CDCl3): δ 134.6 (d, J = 9.3 Hz), 133.7 (d, J = 12.6 Hz), 133.5 (d, J = 3.4
Hz), 132.8 (d, J = 10.7 Hz), 128.8 (d, J = 1.8 Hz), 127.21, 127.18, 126.3, 125.4, 124.6 (d, J =
16.6 Hz), 71.1 (d, J = 5.4 Hz), 24.3 (d, J = 3.8 Hz), 23.9 (d, J = 5.0 Hz). 31P{1H} NMR (162
MHz, CDCl3): δ 16.7.
Dibutyl naphthalen-1-ylphosphonate (3k). Elution with petroleum ether/ethyl acetate 1:1
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(v/v), brown oil (59.7 mg, 93%). H NMR (400 MHz, CDCl3): δ 8.51 (d, J = 8.5 Hz, 1H),
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8.25 (ddd, J = 16.3, 7.0, 0.9 Hz, 1H), 8.03 (d, J = 8.2 Hz, 1H), 7.89 (d, J = 8.1 Hz, 1H), 7.65–
7.58 (m, 1H), 7.58–7.48 (m, 2H), 4.14 (dq, J = 10.0, 6.7 Hz, 2H), 4.00 (dq, J = 10.0, 6.7 Hz,
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2H), 1.70–1.60 (m, 4H), 1.42–1.30 (m, 4H), 0.86 (t, J = 7.4 Hz, 6H). C{1H} NMR (101
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MHz, CDCl3): δ 134.7 (d, J = 9.1 Hz), 133.7 (d, J = 3.4 Hz), 133.6 (d, J = 12.6 Hz), 132.8 (d,
J = 10.9 Hz), 128.8 (d, J = 1.8 Hz), 127.4, 126.8 (d, J = 4.2 Hz), 126.4, 124.7 (d, J = 182.8
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Hz), 124.6 (d, J = 16.6 Hz), 65.9 (d, J = 5.5 Hz), 32.5 (d, J = 6.7 Hz), 18.8, 13.6. P{1H}
NMR (162 MHz, CDCl3): δ 19.4. HRMS (ESI-TOF) m/z: [M + Na]+ Calcd for C18H25O3NaP
343.1434; Found 343.1420.
Ethyl naphthalen-1-yl(phenyl)phosphinate (3l).21 Elution with petroleum ether/ethyl acetate
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1:1 to 2:1 (v/v), colorless oil (46.7 mg, 79%). H NMR (400 MHz, CDCl3): δ 8.59–8.48 (m,
1H), 8.23 (dd, J = 14.7, 7.1 Hz, 1H), 8.02 (d, J = 8.2 Hz, 1H), 7.91–7.76 (m, 3H), 7.55 (dt, J
= 8.3, 2.3 Hz, 1H), 7.51–7.44 (m, 3H), 7.44–7.37 (m, 2H), 4.27–4.08 (m, 2H), 1.38 (t, J = 7.0
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Hz, 3H). C{1H} NMR (101 MHz, CDCl3): δ 134.2 (d, J = 8.4 Hz), 133.8 (d, J = 10.9 Hz),
133.6 (d, J = 3.0 Hz), 133.1 (d, J = 14.8 Hz), 132.4 (d, J = 111.2 Hz), 132.1 (d, J = 2.8 Hz),
131.4 (d, J = 10.6 Hz), 128.7, 128.5, 127.5, 127.3 (d, J = 132.3 Hz), 126.5 (d, J = 4.8 Hz),
126.4, 124.7 (d, J = 14.1 Hz), 61.3 (d, J = 5.8 Hz), 16.6 (d, J = 6.7 Hz). 31P{1H} NMR (162
MHz, CDCl3): δ 32.2.
(7-Methoxynaphthalen-1-yl)diphenylphosphine oxide (3m). Elution with petroleum
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ether/ethyl acetate 1:1 (v/v), white solid (71.0 mg, 99%), mp 117-119 °C. H NMR (400
MHz, CDCl3): δ 7.93 (d, J = 8.0 Hz, 1H), 7.87 (s, 1H), 7.80–7.67 (m, 5H), 7.55 (t, J = 7.0 Hz,
2H), 7.51–7.42 (m, 4H), 7.37–7.21 (m, 2H), 7.13 (dd, J = 9.0, 2.2 Hz, 1H), 3.62 (s, 3H).
13C{1H} NMR (101 MHz, CDCl3): δ 158.4, 135.3 (d, J = 8.1 Hz), 134.2 (d, J = 11.8 Hz),
133.1 (d, J = 2.7 Hz), 132.8 (d, J = 104.1 Hz), 132.1 (d, J = 9.8 Hz), 132.0 (d, J = 2.7 Hz),
130.2 (d, J = 0.6 Hz), 129.4 (d, J = 9.0 Hz), 128.7 (d, J = 12.1 Hz), 127.2 (d, J = 103.3 Hz),
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122.1 (d, J = 14.2 Hz), 119.6, 106.0 (d, J = 6.1 Hz), 55.3. 31P{1H} NMR (162 MHz, CDCl3):
δ 31.8. HRMS (ESI-TOF) m/z: [M + Na]+ Calcd for C23H19O2NaP 381.1015; Found
381.0999.
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5-(Diphenylphosphoryl)-1-naphthonitrile (3n). Elution with petroleum ether/ethyl acetate 1:1
(v/v), colorless oil (60.4 mg, 85%). 1H NMR (400 MHz, CDCl3): δ 8.99 (dd, J = 8.7, 0.7 Hz,
1H), 8.46 (d, J = 8.4 Hz, 1H), 7.95 (dd, J = 7.2, 0.9 Hz, 1H), 7.71–7.62 (m, 4H), 7.62–7.56
(m, 3H), 7.54–7.45 (m, 5H), 7.39 (ddd, J = 15.4, 7.1, 1.0 Hz, 1H). 13C{1H} NMR (101 MHz,
CDCl3): δ 135.1 (d, J = 11.5 Hz), 133.7 (d, J = 8.4 Hz), 133.3, 133.2 (d, J = 9.2 Hz), 133.1 (d,
J = 5.7 Hz), 132.5 (d, J = 2.8 Hz), 132.14 (d, J = 9.9 Hz), 132.13 (d, J = 105.3 Hz), 130.8 (d,
J = 100.6 Hz), 130.2 (d, J = 2.7 Hz), 128.9 (d, J = 12.3 Hz), 127.0 (d, J = 13.9 Hz), 126.6,
117.6 (d, J = 0.8 Hz), 111.2 (d, J = 1.7 Hz). 31P{1H} NMR (162 MHz, CDCl3): δ 32.2.
HRMS (ESI-TOF) m/z: [M + Na]+ Calcd for C23H16ONNaP 376.0862; Found 376.0848.
Naphthalen-2-yldiphenylphosphine oxide (3o).5e Elution with petroleum ether/ethyl acetate
1:1 (v/v), light yellow solid (55.2 mg, 84%). 1H NMR (400 MHz, CDCl3): δ 8.29 (d, J = 14.0
Hz, 1H), 7.94–7.83 (m, 3H), 7.78–7.68 (m, 4H), 7.64 (ddd, J = 9.9, 8.5, 1.4 Hz, 1H), 7.61–
7.50 (m, 4H), 7.50–7.41 (m, 4H). 13C{1H} NMR (101 MHz, CDCl3): δ 134.7 (d, J = 2.3 Hz),
134.0 (d, J = 9.3 Hz), 132.5 (d, J = 104.2 Hz), 132.4 (d, J = 13.3 Hz), 132.2 (d, J = 9.9 Hz),
132.1 (d, J = 2.8 Hz), 129.5 (d, J = 104.3 Hz), 129.0, 128.6 (d, J = 12.1 Hz), 128.4, 128.3,
127.9, 127.0, 126.8 (d, J = 10.7 Hz). 31P{1H} NMR (162 MHz, CDCl3): δ 29.3.
Anthracen-2-yldiphenylphosphine oxide (3p).22 Elution with petroleum ether/ethyl acetate 1:1
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(v/v), white solid (62.2 mg, 82%). H NMR (400 MHz, CDCl3): δ 8.52–8.39 (m, 3H), 8.07–
7.95 (m, 3H), 7.81–7.71 (m, 4H), 7.61–7.53 (m, 3H), 7.52–7.43 (m, 6H). 13C{1H} NMR (101
MHz, CDCl3): δ 135.5 (d, J = 9.1 Hz), 133.1, 132.5 (d, J = 103.6 Hz), 132.3 (d, J = 9.9 Hz),
132.1 (d, J = 2.7 Hz), 132.04 (d, J = 2.3 Hz), 132.01, 130.3 (d, J = 13.9 Hz), 129.1 (d, J =
103.5 Hz), 128.9, 128.7 (d, J = 12.1 Hz), 128.5, 128.3 (d, J = 3.2 Hz), 126.6, 126.5 (d, J = 0.4
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Hz), 126.1, 125.3 (d, J = 10.7 Hz). 31P{1H} NMR (162 MHz, CDCl3): δ 29.3.
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Diphenyl(pyren-4-yl)phosphine oxide (3q). Elution with petroleum ether/ethyl acetate 1:1
(v/v), white solid (79.6 mg, 99%), mp 216-218 °C. 1H NMR (400 MHz, CDCl3): δ 8.93 (dd, J
= 9.3, 0.5 Hz, 1H), 8.21 (t, J = 7.2 Hz, 2H), 8.15 (d, J = 8.9 Hz, 1H), 8.10–7.97 (m, 4H),
7.80–7.66 (m, 5H), 7.58–7.51 (m, 2H), 7.50–7.41 (m, 4H). 13C{1H} NMR (101 MHz, CDCl3):
δ 134.3 (d, J = 2.6 Hz), 134.2 (d, J = 8.1 Hz), 133.4 (d, J = 104.4 Hz), 132.3 (d, J = 9.8 Hz),
132.0 (d, J = 2.8 Hz), 131.3 (d, J = 12.2 Hz), 131.1 (d, J = 0.8 Hz), 130.5, 129.5 (d, J = 95.5
Hz), 128.7 (d, J = 12.2 Hz), 127.2 (d, J = 0.7 Hz), 126.6, 126.4 (d, J = 6.5 Hz), 126.3, 125.7,
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125.2 (d, J = 10.3 Hz), 124.7, 124.3 (d, J = 0.9 Hz), 123.7 (d, J = 13.7 Hz). P{1H} NMR
(162 MHz, CDCl3): δ 32.9. HRMS (ESI-TOF) m/z: [M + Na]+ Calcd for C28H19ONaP
425.1066; Found 425.1050.
Diphenyl(pyridin-2-yl)phosphine oxide (3r).11 Elution with petroleum ether/ethyl acetate 1:1
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(v/v), white solid (49.5 mg, 89%). H NMR (400 MHz, CDCl3): δ 8.78 (d, J = 4.6 Hz, 1H),
8.31 (t, J = 6.7 Hz, 1H), 7.96–7.78 (m, 5H), 7.57–7.49 (m, 2H), 7.49–7.42 (m, 4H), 7.42–7.35
(m, 1H). 13C{1H} NMR (101 MHz, CDCl3): δ 156.4 (d, J = 131.6 Hz), 150.3 (d, J = 19.2 Hz),
136.3 (d, J = 9.3 Hz), 132.24 (d, J = 9.5 Hz), 132.23 (d, J = 104.1 Hz), 132.0 (d, J = 2.8 Hz),
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128.6, 128.5 (d, J = 12.1 Hz), 125.4 (d, J = 3.1 Hz). P{1H} NMR (162 MHz, CDCl3): δ
21.0.
Benzyldiphenylphosphine
oxide
(4a).23
Elution
with
petroleum
ether/ethyl
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acetate/dichloromethane 2:2:1 (v/v), white solid (37.5 mg, 64%). H NMR (400 MHz,
CDCl3): δ 7.75–7.64 (m, 4H), 7.55–7.48 (m, 2H), 7.47–7.38 (m, 4H), 7.24–7.14 (m, 3H),
7.14–7.06 (m, 2H), 3.65 (d, J = 13.7 Hz, 2H). 13C{1H} NMR (101 MHz, CDCl3): δ 132.5 (d,
J = 99.5 Hz), 131.9 (d, J = 2.7 Hz), 131.3 (d, J = 9.1 Hz), 130.3 (d, J = 5.3 Hz), 128.6 (d, J =
31
11.7 Hz), 128.5 (d, J = 2.5 Hz), 126.9 (d, J = 3.0 Hz), 38.3 (d, J = 66.6 Hz). P{1H} NMR
(162 MHz, CDCl3): δ 29.5.
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acetate/dichloromethane 2:2:1 (v/v), white solid (34.9 mg, 54%). H NMR (400 MHz,
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CDCl3): δ 7.76–7.60 (m, 4H), 7.55–7.47 (m, 2H), 7.47–7.38 (m, 4H), 7.02 (dd, J = 8.6, 2.0
Hz, 2H), 6.73 (d, J = 8.6 Hz, 2H), 3.74 (s, 3H), 3.60 (d, J = 13.3 Hz, 2H). 13C{1H} NMR (101
MHz, CDCl3): δ 158.6 (d, J = 2.8 Hz), 132.5 (d, J = 98.5 Hz), 131.9 (d, J = 2.7 Hz), 131.3 (d,
J = 9.0 Hz), 131.2, 128.6 (d, J = 11.6 Hz), 123.0 (d, J = 8.1 Hz), 114.0 (d, J = 2.5 Hz), 55.3,
37.2 (d, J = 67.4 Hz). 31P{1H} NMR (162 MHz, CDCl3): δ 29.6.
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Diphenyl(4-(trifluoromethyl)benzyl)phosphine oxide (4c).5i Elution with petroleum
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ether/ethyl acetate/dichloromethane 2:2:1 (v/v), white solid (28.9 mg, 40%). H NMR (400
MHz, CDCl3): δ 7.74–7.66 (m, 4H), 7.58–7.50 (m, 2H), 7.50–7.38 (m, 6H), 7.23 (d, J = 7.0
Hz, 2H), 3.70 (d, J = 13.7 Hz, 2H). 13C{1H} NMR (101 MHz, CDCl3): δ 135.6 (dd, J = 8.0,
1.1 Hz), 132.2 (d, J = 2.8 Hz), 131.9 (d, J = 99.9 Hz), 131.2 (d, J = 9.3 Hz), 130.5 (d, J = 5.1
Hz), 129.1 (dd, J = 32.4, 3.0 Hz), 128.8 (d, J = 11.8 Hz), 125.5–125.2 (m), 124.2 (q, J =
272.0 Hz), 38.1 (d, J = 65.2 Hz). 19F{1H} NMR (376 MHz, CDCl3): δ –62.50, –62.51. 31P{1H}
NMR (162 MHz, CDCl3): δ 29.0.
(4-Fluorobenzyl)diphenylphosphine oxide (4d).5i Elution with petroleum ether/ethyl
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acetate/dichloromethane 2:2:1 (v/v), white solid (36.8 mg, 59%). H NMR (400 MHz,
CDCl3): δ 7.76–7.62 (m, 4H), 7.56–7.48 (m, 2H), 7.48–7.38 (m, 4H), 7.12–7.01 (m, 2H),
6.87 (t, J = 8.7 Hz, 2H), 3.62 (d, J = 13.4 Hz, 2H). 13C{1H} NMR (101 MHz, CDCl3): δ
162.0 (dd, J = 245.3, 3.2 Hz), 132.2 (d, J = 99.4 Hz), 132.0 (d, J = 2.7 Hz), 131.7 (dd, J = 8.0,
5.3 Hz), 131.2 (d, J = 9.1 Hz), 128.7 (d, J = 11.7 Hz), 126.9 (dd, J = 8.0, 3.3 Hz), 115.4 (dd, J
= 21.5, 2.5 Hz), 37.3 (d, J = 66.8 Hz). 19F{1H} NMR (376 MHz, CDCl3): δ –115.9 (d, J = 4.8
Hz). 31P{1H} NMR (162 MHz, CDCl3): δ 29.3 (d, J = 4.8 Hz).
(4-Chlorobenzyl)diphenylphosphine oxide (4e).5i Elution with petroleum ether/ethyl
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acetate/dichloromethane 2:2:1 (v/v), white solid (13.9 mg, 21%). H NMR (400 MHz,
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CDCl3): δ 7.74–7.64 (m, 4H), 7.58–7.50 (m, 2H), 7.49–7.40 (m, 4H), 7.16 (d, J = 8.3 Hz, 2H),
7.04 (dd, J = 8.4, 1.9 Hz, 2H), 3.61 (d, J = 13.5 Hz, 2H). 13C{1H} NMR (101 MHz, CDCl3):
δ 133.0 (d, J = 3.6 Hz), 132.11 (d, J = 2.7 Hz), 132.09 (d, J = 99.6 Hz), 131.5 (d, J = 5.2 Hz),
131.2 (d, J = 9.2 Hz), 129.8 (d, J = 8.1 Hz), 128.74 (d, J = 11.6 Hz), 128.67, 37.6 (d, J = 66.2
Hz). 31P{1H} NMR (162 MHz, CDCl3): δ 29.2.
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4-((Diphenylphosphoryl)methyl)-N,N-dimethylbenzamide (4f). Elution with petroleum
ether/ethyl acetate/dichloromethane 2:2:1 (v/v), white solid (62.0 mg, 85%), mp 187-189 °C.
1H NMR (400 MHz, CDCl3): δ 7.71 (d, J = 7.6 Hz, 2H), 7.68 (d, J = 7.6 Hz, 2H), 7.52 (t, J =
7.3 Hz, 2H), 7.48–7.40 (m, 4H), 7.25 (d, J = 8.0 Hz, 2H), 7.19–7.11 (m, 2H), 3.67 (d, J =
13
13.8 Hz, 2H), 3.07 (s, 3H), 2.92 (s, 3H). C{1H} NMR (101 MHz, CDCl3): δ 171.4 (d, J =
0.8 Hz), 134.8 (d, J = 3.1 Hz), 133.1 (d, J = 8.0 Hz), 132.3 (d, J = 99.4 Hz), 132.1 (d, J = 2.7
Hz), 131.2 (d, J = 9.2 Hz), 130.2 (d, J = 5.3 Hz), 128.7 (d, J = 11.8 Hz), 127.4 (d, J = 2.5 Hz),
39.7, 38.2 (d, J = 65.9 Hz), 35.5. 31P{1H} NMR (162 MHz, CDCl3): δ 29.1. HRMS
(ESI-TOF) m/z: [M + Na]+ Calcd for C22H22O2NNaP 386.1280; Found 386.1260.
4-((Diphenylphosphoryl)methyl)benzonitrile (4g).24 Elution with petroleum ether/ethyl
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acetate/dichloromethane 2:2:1 (v/v), white solid (31.9 mg, 50%). H NMR (400 MHz,
CDCl3): δ 7.70 (d, J = 7.9 Hz, 2H), 7.67 (d, J = 7.8 Hz, 2H), 7.54 (t, J = 7.2 Hz, 2H), 7.50–
7.40 (m, 6H), 7.22 (d, J = 7.3 Hz, 2H), 3.69 (d, J = 13.7 Hz, 2H). 13C{1H} NMR (101 MHz,
CDCl3): δ 137.2 (d, J = 8.1 Hz), 132.3 (d, J = 2.7 Hz), 132.1 (d, J = 9.0 Hz), 131.1 (d, J = 9.2
Hz), 130.9 (d, J = 5.1 Hz), 128.8 (d, J = 11.9 Hz), 118.9 (d, J = 1.6 Hz), 110.8 (d, J = 3.1 Hz),
38.5 (d, J = 64.2 Hz). 31P{1H} NMR (162 MHz, CDCl3): δ 28.7.
(2-Fluorobenzyl)diphenylphosphine oxide (4h).25 Elution with petroleum ether/ethyl
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acetate/dichloromethane 2:2:1 (v/v), white solid (46.0 mg, 74%). H NMR (400 MHz,
CDCl3): δ 7.78–7.68 (m, 4H), 7.54–7.48 (m, 2H), 7.48–7.39 (m, 5H), 7.19–7.10 (m, 1H),
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7.03 (t, J = 7.5 Hz, 1H), 6.88 (t, J = 9.1 Hz, 1H), 3.70 (d, J = 13.7 Hz, 2H). C{1H} NMR
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(101 MHz, CDCl3): δ 160.7 (dd, J = 245.6, 6.2 Hz), 132.2 (d, J = 99.8 Hz), 132.3–132.2 (m),
132.0 (d, J = 2.8 Hz), 131.2 (d, J = 9.3 Hz), 128.8 (dd, J = 8.3, 3.0 Hz), 128.6 (d, J = 11.8 Hz),
124.3 (t, J = 3.2 Hz), 118.8 (dd, J = 15.3, 7.8 Hz), 115.3 (dd, J = 22.3, 2.4 Hz), 30.3 (dd, J =
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67.5, 2.1 Hz). F{1H} NMR (376 MHz, CDCl3): δ –117.2 (d, J = 3.1 Hz). P{1H} NMR
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(162 MHz, CDCl3): δ 29.5 (d, J = 3.0 Hz).
1-(2-((Diphenylphosphoryl)methyl)phenyl)-2,2-dimethylpropan-1-one (4i). Elution with
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petroleum ether/ethyl acetate/dichloromethane 2:2:1 (v/v), colorless oil (15.9 mg, 21%). H
NMR (400 MHz, CDCl3): δ 7.78–7.65 (m, 4H), 7.55–7.38 (m, 7H), 7.35–7.29 (m, 1H), 7.24–
7.14 (dd, J = 6.1, 3.3 Hz, 2H), 3.73 (dd, J = 14.0, 2.0 Hz, 2H), 1.27 (d, J = 2.6 Hz, 9H).
13C{1H} NMR (101 MHz, CDCl3): δ 214.3, 140.7 (d, J = 6.8 Hz), 132.6 (d, J = 99.6 Hz),
131.9 (d, J = 2.7 Hz), 131.5 (d, J = 4.9 Hz), 131.2 (d, J = 9.3 Hz), 129.3 (d, J = 2.2 Hz),
129.2 (d, J = 7.4 Hz), 128.7 (d, J = 11.8 Hz), 125.9 (d, J = 2.2 Hz), 125.8 (d, J = 1.6 Hz), 45.1,
34.2 (d, J = 67.1 Hz), 28.1. 31P{1H} NMR (162 MHz, CDCl3): δ 30.1. HRMS (ESI-TOF) m/z:
[M + Na]+ Calcd for C24H25O2NaP 399.1484; Found 399.1467.
(Naphthalen-1-ylmethyl)diphenylphosphine oxide (4j).5i Elution with petroleum ether/ethyl
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acetate/dichloromethane 2:2:1 (v/v), white solid (39.6 mg, 58%). H NMR (400 MHz,
CDCl3): δ 7.92 (d, J = 8.2 Hz, 1H), 7.78 (d, J = 7.5 Hz, 1H), 7.74–7.64 (m, 5H), 7.48 (dt, J =
7.3, 1.0 Hz, 2H), 7.44–7.34 (m, 6H), 7.31–7.21 (m, 2H), 4.13 (d, J = 14.0 Hz, 2H). 13C{1H}
NMR (101 MHz, CDCl3): δ 133.9 (d, J = 2.1 Hz), 132.6 (d, J = 4.4 Hz), 132.4 (d, J = 98.8
Hz), 131.9 (d, J = 2.5 Hz), 131.3 (d, J = 9.1 Hz), 128.8 (d, J = 6.2 Hz), 128.6, 128.58 (d, J =
11.7 Hz), 127.9, 127.8 (d, J = 3.5 Hz), 126.1, 125.7, 125.3 (d, J = 3.2 Hz), 124.4 (d, J = 1.2
Hz), 35.0 (d, J = 66.9 Hz). 31P{1H} NMR (162 MHz, CDCl3): δ 29.5.
((4-Methoxynaphthalen-1-yl)methyl)diphenylphosphine oxide (4k). Elution with petroleum
ether/ethyl acetate/dichloromethane 2:2:1 (v/v), white solid (37.2 mg, 50%), mp 197-199 °C.
1H NMR (400 MHz, CDCl3): δ 8.23 (d, J = 7.7 Hz, 1H), 7.80 (d, J = 8.0 Hz, 1H), 7.69 (dd, J
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= 11.2, 7.6 Hz, 4H), 7.51–7.31 (m, 8H), 7.22 (dd, J = 7.9, 3.0 Hz, 1H), 6.65 (d, J = 8.0 Hz,
1H), 4.04 (d, J = 13.7 Hz, 2H), 3.95 (s, 3H). 13C{1H} NMR (101 MHz, CDCl3): δ 154.9 (d, J
= 2.9 Hz), 133.2 (d, J = 4.4 Hz), 132.6 (d, J = 98.3 Hz), 131.8 (d, J = 2.7 Hz), 131.3 (d, J =
9.1 Hz), 128.7 (d, J = 6.4 Hz), 128.5 (d, J = 11.6 Hz), 126.4, 125.9 (d, J = 1.8 Hz), 124.9,
124.1, 122.3, 119.3 (d, J = 8.4 Hz), 103.4 (d, J = 3.0 Hz), 55.5, 34.2 (d, J = 68.0 Hz). 31P{1H}
NMR (162 MHz, CDCl3): δ 29.4. HRMS (ESI-TOF) m/z: [M + Na]+ Calcd for C24H21O2NaP
395.1171; Found 395.1157.
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(Naphthalen-2-ylmethyl)diphenylphosphine oxide (4l).5i Elution with petroleum ether/ethyl
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acetate/dichloromethane 2:2:1 (v/v), white solid (58.4 mg, 85%). H NMR (400 MHz,
CDCl3): δ 7.79–7.62 (m, 7H), 7.57 (s, 1H), 7.53–7.46 (m, 2H), 7.46–7.33 (m, 6H), 7.23 (d, J
= 8.4 Hz, 1H), 3.81 (d, J = 13.8 Hz, 2H). 13C{1H} NMR (101 MHz, CDCl3): δ 133.4 (d, J =
2.7 Hz), 132.4 (d, J = 99.0 Hz), 132.3 (d, J = 2.1 Hz), 132.2 (d, J = 9.9 Hz), 132.0 (d, J = 2.7
Hz), 131.3 (d, J = 9.1 Hz), 129.1 (d, J = 6.7 Hz), 128.9 (d, J = 8.2 Hz), 128.6 (d, J = 11.7 Hz),
128.3 (d, J = 4.3 Hz), 128.0 (d, J = 2.0 Hz), 127.7 (dd, J = 8.1, 1.0 Hz), 126.1, 125.8 (d, J =
1.0 Hz), 38.4 (d, J = 66.4 Hz). 31P{1H} NMR (162 MHz, CDCl3): δ 29.5.
((6-Methoxynaphthalen-2-yl)methyl)diphenylphosphine oxide (4m). Elution with petroleum
ether/ethyl acetate/dichloromethane 2:2:1 (v/v), white solid (65.6 mg, 88%), mp 184-186 °C.
1H NMR (400 MHz, CDCl3): δ 7.76–7.66 (m, 4H), 7.55 (d, J = 8.6 Hz, 2H), 7.53–7.46 (m,
3H), 7.45–7.37 (m, 4H), 7.19 (d, J = 8.4 Hz, 1H), 7.07 (dd, J = 8.9, 2.4 Hz, 1H), 7.04 (d, J =
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2.2 Hz, 1H), 3.87 (s, 3H), 3.77 (d, J = 13.7 Hz, 2H). C{1H} NMR (101 MHz, CDCl3): δ
157.6 (d, J = 1.0 Hz), 133.4 (d, J = 2.1 Hz), 132.4 (d, J = 98.8 Hz), 132.2 (d, J = 9.9 Hz),
131.9 (d, J = 2.7 Hz), 131.3 (d, J = 9.1 Hz), 129.2 (d, J = 0.5 Hz), 128.9 (dd, J = 4.7, 1.9 Hz),
128.8 (d, J = 4.3 Hz), 128.6 (d, J = 11.7 Hz), 126.9 (d, J = 2.0 Hz), 126.3 (d, J = 8.3 Hz),
118.9, 105.6 (d, J = 0.8 Hz), 55.4, 38.2 (d, J = 66.7 Hz). 31P{1H} NMR (162 MHz, CDCl3): δ
29.5. HRMS (ESI-TOF) m/z: [M + Na]+ Calcd for C24H21O2NaP: 395.1171; Found 395.1166.
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