Copper-catalyzed synthesis of unsymmetrical triarylphosphines

Article abstract of DOI:10.1021/jo0343376

Various triarylphosphines have been prepared by coupling diphenylphosphine with aryl iodides with catalytic amounts of CuI in the presence of either K₂CO₃ or CS₂CO₃, in good yields. This method can tolerate a variety of functional groups and does not require the use of expensive additives, or harsh reaction conditions, and is palladium free.

Full text of DOI:10.1021/jo0343376

In recent years, the DV group,22-27 Buchwald group,28-33
and others34-38 have been developing copper-catalyzed
cross-coupling reactions. These methods have demon-
strated increased functional group tolerance and im-
provement over the traditional Ullmann-type reaction
conditions.39 In addition, there exists an economic at-
tractiveness to develop copper-based methods, since they
are the methods of choice for large and industrial scale
reactions. We now report the extension of copper-
catalyzed cross-coupling reactions for the formation of
unsymmetrical triarylphosphines.
Cop p er -Ca ta lyzed Syn th esis of
Un sym m etr ica l Tr ia r ylp h osp h in es†
Derek Van Allen and D. Venkataraman*
Department of Chemistry,
University of Massachusetts Amherst,
710 North Pleasant Street,
Amherst, Massachusetts 01003
dv@chem.umass.edu
To establish the efficacy of copper-based catalysts for
the formation of triarylphosphines, we first studied the
cross-coupling reaction between iodobenzene and di-
phenylphosphine using [Cu(PPh3)3Br], [Cu(Phen)PPh3Br],
[Cu(Neocup)PPh3Br], and [Cu(Neocup)2Br‚H2O] as cata-
lysts, toluene as the solvent, and K2CO3 as the base. We
also studied the efficacy of the copper halides alone, as
well as with ligands as additives, to catalyze this reaction
(Table 1). We were pleased to find that both well-defined
catalysts and copper halides with additives were found
to catalyze this reaction. Moreover, we found that tri-
phenylphosphine was formed in quantitative yields using
Received March 13, 2003
Abstr a ct: Various triarylphosphines have been prepared
by coupling diphenylphosphine with aryl iodides with cata-
lytic amounts of CuI in the presence of either K2CO3 or
Cs2CO3, in good yields. This method can tolerate a variety
of functional groups and does not require the use of
expensive additives, or harsh reaction conditions, and is
palladium free.
Arylphosphine ligands are extremely important for
many reactions catalyzed by transition metals and are
ubiquitous in organometallic chemistry.1-3 Triarylphos-
phine ligands are well-known for their use in asymmetric
catalysis as well as general metal-catalyzed procedures
for aryl-carbon and aryl-heteroatom bond-forming
reactions.4-8 The classical methods of preparation of
arylphosphines often involve reactions of aryl-Grignard
or aryl-lithium reagents with phosphine halides, and are
therefore intolerant to a wide variety of functional
groups.1,3 Many of these methods suffer the disadvantage
of significant, if not exclusive oxidation to the phosphine
oxide, often requiring an additional reductive step. More
recently, palladium- and nickel-catalyzed procedures
have emerged as a more tolerant method of preparing
arylphosphines. However, in contrast to the volume of
literature that exists for the formation of aryl-nitrogen
and aryl-oxygen bonds using cross-coupling reactions
with palladium catalysts, only a very few reports exist
for the formation of arylphosphines, particularly unsym-
metrical phosphines.9-21
(13) Gilbertson, S. R.; Starkey, G. W. J . Org. Chem. 1996, 61, 2922-
2923.
(14) Herd, O.; Hessler, A.; Hingst, M.; Tepper, M.; Stelzer, O. J .
Organomet. Chem. 1996, 522, 69-76.
(15) Lipshutz, B. H.; Buzard, D. J .; Yun, C. S. Tetrahedron Lett.
1999, 40, 201-204.
(16) Tunney, S. E.; Stille, J . K. J . Org. Chem. 1987, 52, 748-753.
(17) Martorell, G.; Garcias, X.; J anura, M.; Saa, J . M. J . Org. Chem.
1998, 63, 3463-3467.
(18) Brauer, D. J .; Hingst, M.; Kottsieper, K. W.; Liek, C.; Nickel,
T.; Tepper, M.; Stelzer, O.; Sheldrick, W. S. J . Organomet. Chem. 2002,
645, 14-26.
(19) Oshiki, T.; Imamoto, T. J . Am. Chem. Soc. 1992, 114, 3975-
3977.
(20) Imamoto, T. Pure Appl. Chem. 1993, 65, 655-660.
(21) Imamoto, T.; Oshiki, T.; Onozawa, T.; Kusumoto, T.; Sato, K.
J . Am. Chem. Soc. 1990, 112, 5244-5252.
(22) Bates, C.; Gujadhur, R.; Venkataraman, D. Org. Lett. 2002, 4,
2803-2806.
(23) Bates, C.; Saejueng, P.; Murphy, J . M.; Venkataraman, D. Org.
Lett. 2002, 3, 4727-4729.
(24) Gujadhur, R.; Bates, C.; Venkataraman, D. Org. Lett. 2001, 3,
4315-4317.
(25) Gujadhur, R.; Venkataraman, D. Synth. Commun. 2001, 2001,
2865-2879.
(26) Gujadhur, R.; Venkataraman, D. Tetrahedron Lett. 2003, 44,
81-84.
† Dedicated to the memory of Prof. William E. McEwen.
(1) Kosolapoff, G. M.; Maier, L. Organic Phosphorous Compounds,
2nd ed.; Wiley-Interscience: New York, 1972; Vol. 1.
(2) Beletskaya, I. P.; Kazankova, M. A. Russ. J . Org. Chem. 2002,
38, 1391-1430.
(27) Gujadhur, R.; Venkataraman, D.; Kintigh, J . Tetrahedron Lett.
2001, 42, 4791-4793.
(28) Marcoux, J . F.; Doye, S.; Buchwald, S. L. J . Am. Chem. Soc.
1997, 119, 10539-10540.
(29) Wolter, M.; Nordmann, G.; J ob, G. E.; Buchwald, S. L. Org. Lett.
2002, 4, 973-976.
(3) Organophosphorous Chemistry; The Royal Society of Chemis-
try: London, UK, 1969-1983; Vols. 1-15.
(30) Klapars, A.; Huang, X. H.; Buchwald, S. L. J . Am. Chem. Soc.
2002, 124, 7421-7428.
(4) Ojima, I. Catalytic Asymmetric Synthesis; VCH: New York, 1993.
(5) Ojima, I.; Clos, N.; Bastos, C. Tetrahedron 1989, 45, 6901-6939.
(6) Wolfe, J . P.; Wagaw, S.; Marcoux, J .-F.; Buchwald, S. L. Acc.
Chem. Res. 1998, 31, 805-818.
(31) Kwong, F. Y.; Klapars, A.; Buchwald, S. L. Org. Lett. 2002, 4,
581-584.
(32) Klapars, A.; Antilla, J . C.; Huang, X. H.; Buchwald, S. L. J .
Am. Chem. Soc. 2001, 123, 7727-7729.
(7) Hartwig, J . F. Acc. Chem. Res. 1998, 31, 852-860.
(8) Heck, R. F. Palladium Reagents in Organic Syntheses; Academic
Press: London, UK, 1985.
(33) Hennessy, E. J .; Buchwald, S. L. Org. Lett. 2002, 4, 269-272.
(34) Zhang, S.; Zhang, D.; Liebeskind, L. S. J . Org. Chem. 1997,
62, 2312-2313.
(9) Ager, D. J .; East, M. B.; Eisenstadt, A.; Laneman, S. A. Chem.
Commun. 1997, 2359-2360.
(35) Ma, D.; Zhang, Y.; Yao, J .; Wu, S.; Tao, F. J . Am. Chem. Soc.
1998, 120, 12459-12467.
(10) Baranano, D.; Mann, G.; Hartwig, J . F. Curr. Org. Chem. 1997,
1, 287-305.
(36) Goodbrand, H. B.; Hu, N.-X. J . Org. Chem. 1999, 64, 670-674.
(37) Fagan, P. J .; Hauptman, E.; Shapiro, R.; Casalnuovo, A. J . Am.
Chem. Soc. 2000, 122, 5043-5051.
(11) Bitterer, F.; Herd, O.; Kuhnel, M.; Stelzer, O.; Weferling, N.;
Sheldrick, W. S.; Hahn, J .; Nagel, S.; Rosch, N. Inorg. Chem. 1998,
37, 6408-6417.
(38) Kalinin, A. V.; Bower, J . F.; Riebel, P.; Snieckus, V. J . Org.
Chem. 1999, 64, 2986-2987.
(12) Cai, D.; Payack, J . F.; Bender, D. R.; Hughes, D. L.; Verhoeven,
T. R.; Reider, P. J . J . Org. Chem. 1994, 59, 7180-7181.
(39) Lindley, J . Tetrahedron 1984, 40, 1433-1456.
10.1021/jo0343376 CCC: $25.00 © 2003 American Chemical Society
Published on Web 05/02/2003
4590
J . Org. Chem. 2003, 68, 4590-4593

TABLE 1. A Com p a r ison of Well-Defin ed Cop p er (I)
TABLE 2. Op tim iza tion of Ba se for Cou p lin g of
Iod oben zen e w ith Dip h en ylp h osp h in e, Usin g Cu I a s th e
Ca ta lyst
Com p lexes, Ad d itives, a n d Cop p er (I) Sa lts
catalyst
GC yield
base
GC yield
well-defined catalysts
Cu(PPh3)3Br
Cu(neocup)PPh3Br
Cu(phen)PPh3Br
Cu(neocup)2Br‚H2O
additives
CuI/phenanthroline
CuI/neocuproine
CuI/DMAP
83
69
61
68
K2CO3
K3PO4
99
94
88
63
52
43
23
0
Cs2CO3
NaOMe
NaOt-Bu
NaOAc
KOt-Bu
NEt3
99
60
54
copper(I) salts
CuI
CuBr
99
34
58
TABLE 3. Syn th esis of Un sym m etr ica l
Tr ia r ylp h osp h in es
CuCl
SCHEME 1. P r otocol for Cop p er (I)-Ca ta lyzed
Cou p lin g of Su bstitu ted Iod oben zen es to
Dip h en ylp h osp h in e
CuI alone as the catalyst. This was contrary to our
observation in other copper-catalyzed coupling reactions
where there were substantial rate accelerations due to
the ligands. We surmised that the product triphenylphos-
phine might form copper-phosphine complexes in situ,
which in turn can accelerate the rate. If this were true,
then we should observe substantial differences between
reactions catalyzed by Cu(PPh3)3Br and CuBr in the rate
of formation of the product during the initial stages of
the reaction. However, we found no differences in the rate
of formation of triphenylphosphine in these reactions.
Hence, we speculate that instead of triphenylphosphine,
diphenylphosphine may be acting as a ligand throughout
the reaction, contributing to the catalytic species.40-44
Among the copper salts, we found CuI to be the most
active catalyst (Table 1). Surprisingly, we have found no
reports on the use of copper halides for the coupling of
diphenylphosphine to aryl halides in the literature. In
the absence of aryl halide, base, or catalyst there is no
observed phosphine product as determined by GC.
We then screened various bases using CuI as the
catalyst for the cross-coupling of iodobenzene with di-
phenylphosphine (Table 2). We found that K2CO3, K3PO4,
and Cs2CO3 were the most effective bases while NEt3,
KOt-Bu, NaOMe, and NaOAc were less effective and
often resulted in little or no observed triphenylphosphine
by GC. However, we found that for several other aryl
iodides, a significant amount of triarylphosphine oxide
was observed when K2CO3 was used as the base. In these
cases, we found that the amount of triarylphosphine
oxide was minimized if Cs2CO3 was used as the base.
Hence, we decided to use CuI (10 mol %) as the catalyst,
Cs2CO3 as the base, and toluene as the solvent as a
standard protocol for the formation of triarylphosphines.
With use of our protocol various electron-withdrawing
and electron-donating aryl iodides were successfully
coupled to diphenylphosphine in good yields (Table 3).
Base-sensitive functional groups such as methyl ketones
(entry 11) and methyl esters (entry 9) are tolerated by
this method. Ortho-substituted iodides also coupled well
with this protocol (entries 3, 4, and 8), as well as bulky
groups and multiple substitutions of the aryl iodide. In
the case of entry 5, although the GC indicated the
(40) A few copper-diphenylphosphine clusters have indeed been
reported in the literature. However, they have not been studied for
their reactivity in cross-coupling reactions. For structures of these
compounds see refs 41-44.
(41) Abel, E. W.; McLean, R. A. N.; Sabherwal, I. H. J . Chem. Soc.
1968, 2371-2373.
(42) Eaborn, C.; Odell, K. J .; Pidcock, A. J . Organomet. Chem. 1979,
170, 105-115.
(43) Eichhofer, A.; Fenske, D.; Holstein, W. Angew. Chem., Int. Ed.
1993, 32, 242-244.
(44) Meyer, C.; Grutzmacher, H.; Pritzkow, H. Angew. Chem., Int.
Ed. 1997, 36, 2471-2473.
J . Org. Chem, Vol. 68, No. 11, 2003 4591

title product. Purification by flash chromatography (pentane/
dichloromethane [3:1] as the eluent) gave the analytically pure
product as a white solid (232 mg, 42% yield). 1H NMR (300 MHz,
CDCl3) δ 7.31-7.14 (m, 14 H), 2.34 (s, 3H; methyl protons).
13C{1H} NMR (75 MHz, CDCl3) δ 138.8, 137.6, 137.5, 134.0,
133.8, 133.7, 133.5, 133.5, 133.4, 129.8, 129.4, 129.3, 128.6, 128.5,
128.4, 128.2, 128.2, 128.1, 21.3. 31P NMR (121 MHz, CDCl3) δ
-5.87 (s). Anal. Calcd for C19H17P: C, 82.59; H, 6.20; P, 11.21.
Found: C, 82.62; H, 6.37; P, 11.4.
complete consumption of the starting materials our
isolated yield of product was moderate. Since the boiling
point (68 °C) of this compound is low, we believe that we
incur loss of the product during isolation of the product
(see Supporting Information). We also found that bromo-
benzene can be coupled with diphenylphosphine under
the same conditions to form triphenylphosphine, but only
in 10% yield.
In conclusion, we have reported a synthetic protocol
for unsymmetrical triarylphosphines starting from aryl
iodides and diphenylphosphine, using CuI as the catalyst
and Cs2CO3 and K2CO3 bases. Our protocol tolerates a
variety of functional groups, including base-sensitive
groups. This method is palladium free and has shown a
dramatic improvement in overall yields, and the reaction
conditions are much less harsh than similar protocols
based on phosphination.
Dip h en yl-o-tolylp h osp h a n e (5).47 The general procedure
was used to convert 2-iodotoluene and diphenylphosphine to the
title product. Purification by flash chromatography (pentane/
dichloromethane [3:1] as the eluent) gave the analytically pure
product as a white solid (420 mg, 76% yield). 1H NMR (300 MHz,
CDCl3) δ 7.32-7.21 (m, 12 H), 7.09-7.04 (t, 1H), 6.79-6.75 (m,
1H), 2.39 (s, 3H; methyl protons). 13C{1H} NMR (75 MHz, CDCl3)
δ 142.3, 142.0, 136.3, 136.2, 135.9, 134.1, 133.9, 132.7, 130.1,
130.0, 128.7, 128.6, 128.5, 126.0, 21.1. 31P NMR (121 MHz,
CDCl3) δ -13.23 (s). Anal. Calcd for C19H17P: C, 82.59; H, 6.20;
P, 11.21. Found: C, 82.44; H, 6.11; P, 11.1.
(4-Bu tylp h en yl)d ip h en ylp h osp h a n e (6). The general pro-
cedure was used to convert 1-butyl-4-iodo-benzene and di-
phenylphosphine to the title product. Purification by flash
chromatography (hexane/dichloromethane [10:1] as the eluent)
gave the analytically pure product as a colorless oil (443 mg,
70% yield). 1H NMR (300 MHz, CDCl3) δ 7.29-7.12 (m, 14 H),
2.59 (t, 2H), 1.59 (t, 2H), 1.34 (m, 2H), 0.91 (t, 3H). 13C{1H} NMR
(75 MHz, CDCl3) δ 143.2, 137.1, 137.0, 133.4, 133.2, 133.1, 133.0,
128.5, 128.2, 128.1, 128.0, 127.9, 127.8, 127.7, 124.8, 34.9, 32.9,
22.1, 13.6. 31P NMR (121 MHz, CDCl3) δ -16.73 (s). Anal. Calcd
for C22H23P: C, 82.99; H, 7.28. Found: C, 82.72; H, 7.30.
(3,5-Dim eth ylp h en yl)d ip h en ylp h osp h a n e (7).14 The gen-
eral procedure was used to convert 1-Iodo-3,5-dimethylbenzene
and diphenylphosphine to the title product. Purification by flash
chromatography (pentane/dichloromethane [3:1] as the eluent)
gave the analytically pure product as a colorless oil (447 mg,
77% yield). 1H NMR (300 MHz, CDCl3) δ 7.31-7.30 (m, 10 H),
6.96-6.92 (m, 3 H), 2.24 (s, 6H; methyl protons). 13C{1H} NMR
(75 MHz, CDCl3) δ 138.0, 137.9, 137.5, 137.4, 136.7, 136.6, 133.8,
133.6, 131.6, 131.4, 130.6, 128.5, 128.3, 128.4. 31P NMR (121
MHz, CDCl3) δ -5.20 (s). Anal. Calcd for C20H19P: C, 82.74; H,
6.60. Found: C, 82.55; H, 6.69.
Exp er im en ta l Section
Gen er a l P r oced u r e. In an argon-filled glovebox, a Pyrex
glass tube (2.5 cm in diameter) equipped with a Teflon stir bar
was charged with cesium carbonate (3.0 mmol) and CuI (10 mol
% with respect to diphenylphosphine), sealed with a rubber
septum, and taken out of the box and toluene (5 mL), the aryl
halide (2.4 mmol), and diphenylphosphine (2.0 mmol) were
injected into the tube through the septum. The reaction mixture
was then heated at 110 °C for 24 h. The reaction mixture was
then cooled to room temperature and filtered with dichloro-
methane to remove any insoluble residues. The filtrate was
concentrated in vacuo; the residue was purified by flash chro-
matography on silica to obtain the analytically pure product.
Tr ip h en ylp h osp h in e (1). The general procedure was used
to convert iodobenzene and diphenylphosphine to the title prod-
uct. Purification by flash chromatography (pentane/dichloro-
methane [2:1] as the eluent) gave the analytically pure product
as a white solid (435 mg, 83% yield). 1H NMR (300 MHz, CDCl3)
δ 7.34-7.22 (m, 15 H). 13C{1H} NMR (75 MHz, CDCl3) δ 137.2,
137.1, 133.8, 133.9, 128.8, 128.5, 128.4. 31P NMR (121 MHz,
CDCl3) δ -4.96 (s). Anal. Calcd for C18H15P: C, 82.43; H, 5.76;
P, 11.81. Found: C, 82.13; H, 5.78.
Dip h en yl(2,4,6-t r im et h ylp h en yl)p h osp h a n e (8).48 The
general procedure was used to convert 2-iodo-1,3,5-trimethyl-
benzene and diphenylphosphine to the title product. Purification
by flash chromatography (pentane/dichloromethane [3:1] as the
eluent) gave the analytically pure product as a colorless oil (432
Na p h th a len -1-yld ip h en ylp h osp h a n e (2).45 The general
procedure was used to convert 1-iodonaphthanlene and di-
phenylphosphine to the title product. Purification by flash
chromatography (dichloromethane as the eluent) gave the
analytically pure product as a white solid (567 mg, 91% yield).
1H NMR (300 MHz, CDCl3) δ 7.51-7.28 (m, 15 H), 7.85 (t, 2H).
13C{1H} NMR (75 MHz, CDCl3) δ 134.3, 134.1, 133.4, 133.4,
132.0, 129.5, 128.8, 128.7, 128.6, 128.5, 126.3, 126.0, 125.9, 125.5.
31P NMR (121 MHz, CDCl3) δ -16.66 (s). Anal. Calcd for
1
mg, 71% yield). H NMR (300 MHz, CDCl3) δ 7.37-7.20 (m, 10
H), 6.90 (s, 2 H), 2.27 (s, 3H; methyl protons), 2.18 (s, 6H; methyl
protons). 13C{1H} NMR (75 MHz, CDCl3) δ 145.6, 145.4, 140.0,
139.9, 136.7, 136.5, 131.6, 131.3, 129.9, 129.9, 129.0, 128.3, 128.3,
127.4, 23.8, 23.6, 21.1. 31P NMR (121 MHz, CDCl3) δ -16.39
(s). Anal. Calcd for C21H21P: C, 82.87; H, 6.95. Found: C, 82.70;
H, 7.25.
C
22H17P: C, 84.60; H, 5.49. Found: C, 84.35; H, 5.49.
(2-Meth oxyp h en yl)d ip h en ylp h osp h a n e (3).46 The general
4-Dip h en ylp h osp h a n ylben zoic Acid Meth yl Ester (9).49
The general procedure was used to convert 4-Iodobenzoic acid
methyl ester and diphenylphosphine to the title product. Puri-
fication by flash chromatography (pentane/ethyl acetate [3:1] as
the eluent) gave the analytically pure product as a white solid
(448 mg, 70% yield). 1H NMR (300 MHz, CDCl3) δ 7.98-7.95
(d, 2 H), 7.36-7.32 (m, 12 H), 3.89 (s, 3H; methyl protons).
13C{1H} NMR (75 MHz, CDCl3) δ 166.8, 144.1, 143.9, 136.2,
136.1, 134.1, 133.8, 133.3, 133.0, 130.0, 129.3, 129.2, 129.1, 128.7,
128.6, 52.1. 31P NMR (121 MHz, CDCl3) δ -5.04 (s). Anal. Calcd
for C20H17OP: C, 74.99; H, 5.35; P, 9.67. Found: C, 74.99; H,
5.46, P, 9.7.
procedure was used to convert 2-iodoanisole and diphenylphos-
phine to the title product. Purification by flash chromatography
(dichloromethane as the eluent) gave the analytically pure
product as a white solid (373 mg, 64% yield). 1H NMR (300 MHz,
CDCl3) δ 7.35-7.26 (m, 11 H), 6.90-6.82 (m, 2 H), 6.69-6.65
(t, 1 H), 3.73 (s, 3H; methyl protons). 13C{1H} NMR (75 MHz,
CDCl3) δ 161.2, 161.0, 136.7, 136.6, 134.0, 133.7, 133.6, 130.3,
128.6, 128.4, 128.3, 125.6, 125.5, 121.0, 110.2, 110.2, 55.6. 31P
NMR (121 MHz, CDCl3)
δ -16.35 (s). Anal. Calcd for
C
19H17OP: C, 78.07; H, 5.86; P, 10.60, O, 5.47. Found: C, 78.19;
H, 6.03; P, 10.4.
Dip h en yl-p-tolylp h osp h a n e (4).14 The general procedure
was used to convert 4-iodotoluene and diphenylphosphine to the
1,4-Bis(d ip h en ylp h osp h a n yl)ben zen e (10).16 The general
procedure was used to convert p-diiodobenzene and diphenyl-
(47) Budnikova, Y.; Kargin, Y.; Ne´de´lec, J .-Y.; Pe´richon, J . J .
Organomet. Chem. 1999, 575, 63-66.
(48) Blount, J . F.; Camp, D.; Hart, R. D.; Healy, P. C.; Skelton, B.
W.; White, A. H. Aust. J . Chem. 1994, 47, 1631-1640.
(49) Danjo, H.; Tanaka, D.; Hayashi, T.; Uozumi, Y. Tetrahedron
1999, 55, 14341-14352.
(45) Carre’, F. H.; Chuit, C.; Corriu, R. J . P.; Douglas, W. E.; Guy,
D. M. H.; Reye’, C. Eur. J . Inorg. Chem. 2000, 647-653.
(46) McEwen, W. E.; Shiau, W.-I.; Yeh, Y.-I.; Schulz, D. N.; Pagi-
lagan, R. U.; Levy, J . B.; Courtland Symmes, J .; Nelson, G.; Granothlc,
I. J . Am. Chem. Soc. 1975, 97, 1787-1794.
4592 J . Org. Chem., Vol. 68, No. 11, 2003

phosphine to the title product. Purification by flash chromatog-
raphy (pentane/dichloromethane [2:1] as the eluent) gave the
title product as an off-white solid (634 mg, 71% yield). 1H NMR
(300 MHz, CDCl3) δ 7.36-7.31 (m, 24 H). 13C{1H} NMR (75 MHz,
CDCl3) δ 138.0, 136.8, 136.7, 136.5, 134.0, 133.7, 133.3, 133.2,
128.9, 128.6, 128.5. 31P NMR (121 MHz, CDCl3) δ -5.20 (s).
HRMS EI calcd for C30H24P2 446.1353, found 446.1353.
1-(4-(Dip h en ylp h osp h a n yl)p h en yl)eth a n on e (11).16 The
general procedure was used to convert 4-iodoacetophenone and
diphenylphosphine to the title product. Purification by flash
chromatography (pentane/dichloromethane [1:6] as the eluent)
gave the title product as an off-white solid (409 mg, 67% yield).
1H NMR (300 MHz, CDCl3) δ 7.29-7.38 (m, 12 H), 7.86-7.89
(dd, 2 H; J ) 1.51 and 6.97 Hz), 3.89 (s, 3H; methyl protons).
13C{1H} NMR (75 MHz, CDCl3) δ 197.8, 144.5, 144.3, 136.8,
136.1, 136.0, 134.1, 133.8, 133.4, 133.2, 129.2, 129.0, 128.8, 128.7,
128.0, 127.9, 26.6. 31P NMR (121 MHz, CDCl3) δ -3.81 (s). Anal.
Calcd for C20H17OP: C, 78.93; H, 5.63; P, 10.18. Found: C, 78.73;
H, 5.70, P, 10.0.
NMR (300 MHz, CDCl3) δ 7.58-7.10 (m, 13 H). 13C{1H} NMR
(75 MHz, CDCl3) δ 138.0, 137.8, 136.5, 136.2, 133.2, 132.9, 132.0,
128.8, 128.6, 128.5, 128.4, 128.1, 127.9. 31P NMR (121 MHz,
CDCl3) δ -19.49 (s). Anal. Calcd for C16H13PS: C, 71.62; H, 4.88;
P, 11.54. Found: C, 71.71; H, 5.00; P, 11.6.
Ack n ow led gm en t. The University of Massachu-
setts, Amherst start-up funds provided the financial
support for this research. D.V. gratefully acknowledges
a Camille and Henry Dreyfus New Faculty Award and
an NSF career Award (CHE-0134287). We thank the
X-ray Structural Characterization Laboratory, sup-
ported by National Science Foundation grant CHE-
9974648, for assistance with the crystallographic analy-
ses.
Su p p or tin g In for m a tion Ava ila ble: General experimen-
tal procedures and the synthesis of well-defined copper(I)
complexes and a crystallographic information file (CIF) for 2.
This material is available free of charge via the Internet at
http://pubs.acs.org.
Dip h en ylth iop h en ylp h osp h a n e (12).16 The general pro-
cedure was used to convert 4-iodoanisole and diphenylphosphine
to the title product. Purification by flash chromatography
(pentane/dichloromethane [3:1] as the eluent) gave the analyti-
1
cally pure product as an off-white solid (338 mg, 63% yield). H
J O0343376
J . Org. Chem, Vol. 68, No. 11, 2003 4593