Convenient and direct preparation of tertiary phosphines via nickel-catalysed cross-coupling

Article abstract of DOI:10.1039/a705106i

Nickel-catalysed cross-coupling of aryl sulfonates and aryl halides with chlorodiphenylphosphine and a reductant directly affords tertiary phosphines, which have application in a wide variety of asymmetric catalysis.

Full text of DOI:10.1039/a705106i

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Convenient and direct preparation of tertiary phosphines via nickel-catalysed
cross-coupling
David J. Ager, Michael B. East, Amihai Eisenstadt and Scott A. Laneman*
NSC Technologies, A unit of Monsanto Company, 601 East Kensington Road, Mt. Prospect, Illinois 60056, USA
Table 1 Examples of nickel-catalysed cross couplings
Nickel-catalysed cross-coupling of aryl sulfonates and aryl
halides with chlorodiphenylphosphine and a reductant
Substrate
Product
Yield (%)
directly affords tertiary phosphines, which have application
in a wide variety of asymmetric catalysis.
4
6
7
5
5
8
89
78
95
84
46
67
46
90a
80
45
52
Tertiary phosphines are extremely useful ancillary ligands in
homogeneous catalysis, especially as chiral ligands in asym-
metric homogeneous catalysis as exemplified by 1–3.1–8 The
preparations of tertiary phosphines can be divided into four
major categories: Friedel–Crafts reactions,9,10 the reaction of
halophosphines with organometallic reagents11,12 and the
reaction of phosphides13–15 or diarylphosphine compounds16–18
in the presence of a transition metal catalyst with aryl halides or
sulfonate esters. All of the methods have drawbacks ranging
from limitations due to incompatabilities with other functional
groups, the necessity for a separate step to reduce the phosphine
oxide, to the use of pyrophoric reagents. We report here a
convenient and direct route to tertiary phosphines by transition
metal cross-coupling reaction that eliminates these problems.
9
10
10
13
15
17
19
21
1
11
12
14
16
18
20
22
a Isolated as the phosphine oxide by air oxidation during work up.
halides and sulfonates that contain ortho-substitution. Benzylic
halides are extremely active substrates and reactions are
completed in minutes. Surprisingly, the coupling reaction
tolerates the presence of amides while carboxylic acid inhibit
reaction.
R
O
N
PPh2
PPh2
O
R′
R′
PPh2
R
R
1
2
9 R = OTf, R′ = OMe
10 R = PPh2, R′ = OMe
11 R = Br, R′ = OMe
4 R = OTf, R′ = H
5 R = PPh2, R′ = H
6 R = Br, R′ = H
O
O
12 R = OTf, R′ = NHBn
7 R = OTf, R′ = CO2Me
8 R = PPh2, R′ = CO2Me
NH
HN
13 R = PPh2, R′ = NHBn
14 R = Br, R′ = (S)-NHCHMePh
15 R = PPh2, R′ = (S)-NHCHMePh
PPh2 Ph2P
3
CO2Me
R
R
Ph
R
CO2Me
OTf
OTf
We have determined that tertiary phosphines can be prepared
from aryl trifluoromethanesulfonates by nickel-catalysed cross-
coupling with Ph2PCl in the presence of zinc in DMF at 110 °C
(Scheme 1). Ph2PCl has the advantage that it is not pyrophoric,
inexpensive and readily available for large scale usage. For
example, 2-diphenylphosphinonaphthalene 5 is prepared from 4
via nickel-catalysed cross-coupling with Ph2PCl in 89% yield.†
The zinc plays a dual role in the reaction. It reduces NiII to Ni0
as well as providing Ph2PZnCl for transmetallation.
This methodology appears to be quite general for the
preparation of other tertiary phosphines (Table 1). The nickel-
catalysed cross-coupling procedure successfully produces phos-
phines in good yields directly from aromatic sulfonates,
aromatic halogens, benzylic bromides and vinyl bromides and
iodides. Also, the cross-coupling can occur with aromatic
Ph
16 R = Br
17 R = PPh2 19 R = PPh2
18 R = OTf
20 R = Br
21 R = PPh2
22
(Tf = CF3SO2)
Trifluoromethanesulfonate substrates give higher yields
compared to the corresponding bromide substrate due to
hydrodehalogenation side reaction. Double cross-coupling of
the S-isomer of the bis(trifluoromethanesulfonate) 22 can be
achieved to form S-BINAP 1 without any racemisation of the
axial chirality.‡
This methodology is a convenient procedure to prepare a
wide variety of tertiary phosphines. The use of a cheap
phosphorus reagent coupled with the tolerance of the reaction to
a wide variety of functional groups as well as direct access to
phosphorus(iii) products makes this a useful, versatile approach
to phosphorus ligands.
PPh2Cl, NiCl2(dppe), Zn
Ar
X
Ar PPh2
Solvent, 110 °C
Scheme 1
Chem. Commun., 1997
2359

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5 S. Akutagawa, Appl. Catal. A, 1995, 128, 171.
6 R. Noyori, Science, 1990, 248, 1194.
7 R. Noyori and H. Takaya, Acc. Chem. Res., 1990, 23, 345.
8 H. Takaya, T. Ohta and R. Noyori, in Asymmetric Hydrogenation, ed. I.
Ojima, New York, NY, 1993.
Footnotes and References
* E-mail: salane@monsanto.com
† Typical reaction procedure: to a solution of 4 (10.6 g, 40 mmol),
NiCl2(dppe) [dppe
= ethylenebis(diphenylphosphine)] (0.315 g, 0.60
mmol) and Ph2PCl (8.85 g, 40 mmol) in anhydrous DMF (25 ml) was added
Zn (4.10 g, 63 mmol) portionwise at 5–10 °C. The mixture was heated to
100–110 °C and monitored by GC. The reaction mixture was cooled to
80 °C, filtered and rinsed with a minimal amount of DMF. The combined
filtrate was cooled to 5 °C and the product crystallised overnight. The solids
were filtered, rinsed with MeOH and dried at room temp. under vacuum to
give 11.21 g (89%) of 5 as an off-white solid. Satisfactory 1H and 31P NMR
and mass spectral data were obtained on all the products.
9 W. Ude, S. Besecke, A. Riemann and G. Schroeder, Ger. Offen., 1986,
DE 3425282 A1.
10 I.-Y. Wan, J. E. McGrath and T. Kashiwagi, ACS Symp. Ser., 1995, 599,
29.
11 E. P. Kyba, M. C. Kerby and S. P. Rines, Organometallics, 1986, 5,
1189.
12 F. Langer, K. Puntener, R. Sturmer and P. Knochel, Tetrahedron:
Asymmetry, 1997, 8, 715.
‡ Optical purities of substrates and products were determined by optical
rotation.
13 S. J. Coote, G.J. Dawson, C. G. Frost and J. M. J. Williams, Synlett,
1993, 509.
14 M. D. Fryzuk and B. Bosnich, J. Am. Chem. Soc., 1977, 99, 6262.
15 M. D. Fryzuk and B. Bosnich, J. Am. Chem. Soc., 1978, 100, 5491.
16 D. Cai, J. F. Payack, D. R. Bender, D. L. Hughes, T. R. Verhoeven and
P. J. Reider, J. Org. Chem., 1994, 59, 7180.
17 S. E. Tunney and J. K. Stille, J. Org. Chem., 1987, 52, 748.
18 S. R. Gilbertson and G. W. Starkey, J. Org. Chem., 1996, 61, 2922.
1 D. J. Ager and M. B. East, Asymmetric Synthetic Methodology, CRC
Press, Boca Raton, FL, 1995.
2 P. von Matt and A. Pfaltz, Angew. Chem., Int. Ed. Engl., 1993, 32,
566.
3 P. von Matt, O. Loiseleur, G. Koch, A. Pfaltz, C. Lefeber, T. Feucht and
G. Helmchen, Tetrahedron: Asymmetry, 1994, 5, 573.
4 B. M. Trost and R. C. Bunt, Angew. Chem., Int. Ed. Engl., 1996, 35,
99.
Received in Corvallis, OR, USA, 16th July 1997; 7/05106I
2360
Chem. Commun., 1997