organic layers were combined, dried over MgSO4, filtered and
evaporated under reduced pressure. Purification of the crude
product by flash chromatography on silica gel afforded 1070 mg
Experimental
All reactions and workup procedures were performed under an
inert atmosphere of argon using conventional vacuum-line and
glasswork techniques. Solvents were dried and freshly distilled
under argon. All other materials were obtained from commercial
suppliers and used as received. Water (deionized) was degassed
by sparging with nitrogen. Chromatography was performed on
neutral silica gel. NMR spectra were recorded on a Bruker
instrument operating at 400.13 MHz for proton, 100.62 MHz for
carbon, and 161.96 MHz for phosphorus.
1
of 4-acetyl-4¢-methoxybiphenyl (91%) as white solid. H NMR
(400.13 MHz, CDCl3): d 7.95 (d, J = 8.8 Hz, 2H), 7.58 (d, J = 8.8
Hz, 2H), 7.52 (d, J = 8.8 Hz, 2H), 6.94 (d, J = 8.8 Hz, 2H), 3.79
(s, 3H), 2.56 (s, 3H). 13C NMR (125 MHz, CDCl3): d 197.7, 159.9,
145.3, 135.3, 132.2, 128.9, 128.3, 126.6, 114.4, 55.4, 26.6.
Acknowledgements
The authors acknowledge Ayoub Hassine for experimental work
during his Master’s training and the Re´gion Picardie for their
financial support.
Synthesis of 1,5-diphenyl-3,7-dicyclohexyl-1,5-diaza-3,7-
diphosphacyclooctane 1
A Schlenk flask was charged with cyclohexylphosphine (10% in
hexane, 14.6 mL, 8.3 mmol) and degassed aqueous formaldehyde
(37%, 1.92 mL, 25.8 mmol) in degassed CH3CN (20 mL). After
stirring for 30 min at room temperature, the solvent was removed
under vacuum and the resulting oil was combined with aniline
(773 mg, 8.3 mmol) in degassed EtOH (20 mL) and the solution
was refluxed overnight. The solution was allowed to cool down
to room temperature. A white precipitate was filtered and washed
with EtOH and dried under vacuum to give a white powder (3.28 g,
Notes and references
1 N. Miyaura, T. Yanagi and A. Suzuki, Synth. Commun., 1981, 11, 513.
2 N. Miyaura and A. Suzuki, Chem. Rev., 1995, 95, 2457.
3 N. Miyaura, Cross-Coupling Reactions: A Practical Guide, Springer,
New York, 2002.
4 J. H. Clark, Green Chem., 2006, 8, 17–21.
5 C. J. Li and L. Chen, Chem. Soc. Rev., 2006, 35, 68–82.
6 M. Poliakoff and P. Licence, Nature, 2007, 450, 810–812.
7 (a) M. C. Pirrung, Chem.–Eur. J., 2006, 12, 1312; (b) A. Chanda and V.
V. Fokin, Chem. Rev., 2009, 109, 725; (c) R. N. Butler and A. G. Coyne,
Chem. Rev., 2010, 110, 6302.
1
7.1 mmol, 85%). 31P{ H} NMR (CDCl3, 161.96 MHz, d in ppm):
1
- 40.9 ppm (s). H NMR (CDCl3, 400.13 MHz): 7.18–7.27 (m,
10H, NC6H5), 4.47 (d, 2H, 2JHH = 12.8 Hz, NCH2P), 4.50 (d, 2H,
8 D. L. Severance and W. L. Jorgensen, J. Am. Chem. Soc., 1992, 114,
10966.
9 R. Breslow, Science, 1982, 218, 532.
10 A. J. Kirby, Angew. Chem., Int. Ed. Engl., 1996, 35, 706.
11 A. Heine, G. Desantis, J. G. Luz, M. Mitchell, C.-H. Wong and I. A.
Wilson, Science, 2001, 294, 369.
12 Aqueous Microwave Assisted Chemistry: Synthesis and Catalysis”, ed.
V. Polshettiwar and R. S. Varma, 2010, Royal Society of Chemistry
(Green Chemistry Series), Cambridge, UK.
13 (a) V. Polshettiwar and R. S. Varma, Chem. Soc. Rev., 2008, 37, 1546;
(b) D. Dallinger and C. O. Kappe, Chem. Rev., 2007, 107, 2563; (c) C. J.
Li and T. H. Chan, Organic Reactions in Aqueous Media, John Wiley &
Sons, New York, 1997; (d) C.-J. Li, T.-H. Chan, Comprehensive organic
reactions in aqueous Media, Wiley and sons, New York,2007.
14 V. Polshettiwar, A. Decottignies, C. Len and A. Fihri, Chem. Sus.
Chem., 2010, 3, 502.
2
2JHH = 12.8 Hz, NCH2P), 4.83 (d, 2H, JHH = 12.8 Hz, NCH2P),
2
4.86 (d, 2H, JHH = 12.8 Hz, NCH2P), 1.82–0.88 (m) (22H total,
1
C6H11). 31C{ H} NMR (CDCl3, 100.62 MHz): 15.21 (d, 4JCP = 1.2
2
1
Hz, CCy), 25.41 (d, JCP = 10.7 Hz, CCy), 28.07 (d, JCP = 14.5
Hz, CCy), 29.66 (d, 3JCP = 9.4 Hz, CCy),45.4 (d, 1JCP = 19.8 Hz,
NCP), 115.8 (s, C6H5), 118.8 (s, C6H5), 128.3 (s, C6H5), 149.6 (s,
C6H5).
Synthesis of 1,5-diphenyl-3,7-dicyclohexyl-1,5-diaza-3,7-
diphosphacyclooctane palladium complex 2
To a 20 mL dichloromethane solution of 0.1 g (0.22 mmol) of 1,5-
diphenyl-3,7-dicyclohexyl-1,5-diaza-3,7-diphosphacyclooctane
was dropwise added a solution of 0.05 g (0.22 mmol) of Pd(OAc)2
in 10 mL of the same solvent. After stirring 2 h at room
temperature, the solvent was removed under vacuum to give a
solid that was washed with cold pentane and dried under vacuum
15 For a discussion, see: (a) V. V. Grushin and H. Alper, in Activation of
Unreactive Bonds and Organic Synthesis, ed. S. Murai, Springer, Berlin,
1999, p. 193; (b) V. V. Grushin and H. Alper, Chem. Rev., 1994, 94,
1047.
16 (a) V. Polshettiwar and R. S. Varma, J. Org. Chem., 2008, 73, 7417;
(b) V. Polshettiwar and R. S. Varma, J. Org. Chem., 2007, 72, 7420;
(c) V. Polshettiwar and R. S. Varma, Tetrahedron Lett., 2008, 49, 397;
(d) V. Polshettiwar and R. S. Varma, Tetrahedron Lett., 2007, 48, 8735;
(e) V. Polshettiwar and R. S. Varma, Tetrahedron Lett., 2007, 48, 5649;
(f) V. Polshettiwar and R. S. Varma, Tetrahedron Lett., 2007, 48, 7343;
(g) Y. Ju and R. S. Varma, J. Org. Chem., 2006, 71, 135.
17 (a) V. Polshettiwar and R. S. Varma, Tetrahedron Lett., 2008, 49, 7165;
(b) V. Polshettiwar and R. S. Varma, Tetrahedron, 2008, 64, 4637; (c) V.
Polshettiwar and R. S. Varma, Tetrahedron Lett., 2008, 49, 879; (d) V.
Polshettiwar and R. S. Varma, Tetrahedron Lett., 2008, 49, 2661.
18 (a) V. Polshettiwar, M. N. Nadagouda and R. S. Varma, Chem.
Commun., 2008, 6318; (b) V. Polshettiwar, B. B. Baruwati and R. S.
Varma, ACS Nano, 2009, 3, 728.
19 (a) V. Polshettiwar and R. S. Varma, Chem.–Eur. J., 2009, 15, 1582;
(b) V. Polshettiwar and R. S. Varma, Org. Biomol. Chem., 2009, 7, 37;
(c) V. Polshettiwar, B. B. Baruwati and R. S. Varma, Green Chem.,
2009, 11, 127; (d) M. N. Nadagouda, V. Polshettiwar and R. S. Varma,
J. Mater. Chem., 2009, 19, 2026; (e) V. Polshettiwar, B. B. Baruwati and
R. S. Varma, Chem. Commun., 2009, 1837.
1
to yield complex 2 as a brown solid (129 mg, 85%). 31P{ H} NMR
(CDCl3, 161.96 MHz, d in ppm): 31.9 ppm (s).1H NMR (CDCl3,
400.13 MHz): 1.5 (s, 6H, CH3), 2.1–0.9 (22 H total, C6H11), 4.13
(d, 2JHH = 13.2 Hz, PCH2N), 4.42 (dd, 2JHH = 14.2 Hz, 2JPH = 5.7
Hz, PCH2N), 4.18 (d, 2JHH = 12.8 Hz, PCH2N), MS (ES): m/z (%):
707.37 (100) [M - NH4]+.
A general procedure for the cross-coupling reaction is as
follows: to a solution of 4-methoxyphenylboronic acid (1.14 g,
7.5 mmol), 4¢-bromoacetophenone (995.25 mg, 5 mmol), K2CO3
(1.38 g, 10 mmol), 1,5-diphenyl-3,7-dicyclohexyl-1,5-diaza-3,7-
diphosphacyclooctane (2.34 mg, 5 10-3 mmol, 0.1 mol%) and
Pd(OAc)2 (1.2 mg, 5 10-3 mmol, 0.1 mol%) in 5 mL water was
flushed with nitrogen and capped. The reaction mixture was heated
and stirred in the oil bath at reflux for 2 h and the reaction mixture
was extracted with dichloromethane (3 ¥ 5 mL). The combined
dichloromethane phase was dried with anhydrous MgSO4. The
20 K. Kellner and A. Tzschach, Z. Chem., 1984, 24, 365.
21 B. A. Arbuzov and G. N. Nikonov, Adv. Heterocycl. Chem., 1994, 61,
60.
3120 | Dalton Trans., 2011, 40, 3116–3121
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