S. López-Cortina et al. / Tetrahedron 66 (2010) 6188e6194
6193
immediately treated with 2.9 g (10.6 mmol, 1.0 mL) of phosphorus
tribromide at 0 ꢀC. When the addition was completed, the ice bath
was removed and the reaction mixture was stirred overnight at
room temperature. The resulting mixture was treated with 30.0 mL
of distilled water and the reddish solid formed removed by filtration.
The filtrate was extracted with dichloromethane, the organic layers
were combined, dried over anhydrous sodium sulfate, and the sol-
phosphine oxide 10a were dissolved in 25.0 mL of dichloro-
methane. To this solution was added solution of 0.26 g
a
(1.77 mmol) of trimethyloxonium tetrafluoroborate in 25.0 mL of
dichloromethane, and the resulting mixture was stirred at room
temperature under nitrogen for 6 h. When the reaction was com-
pleted, the solvent was evaporated and 0.33 g (83%) of the product
11a were isolated as a white solid, mp 100e102 ꢀC. 1H NMR (CDCl3,
vent evaporated to give 2.37 g (98%) of 8 as a colorless oil. 1H NMR
200 MHz) d 1.78 (m, 4H, H2,6), 2.11(m, 4H, H3,5), 2.75e3.14 (m, 1H,
3
(CDCl3, 400 MHz)
d
2.2 (m, 4H, H2,4
,
3JH2,4-H3¼8.0, JH2,4-H1,5¼6.0),
H4, 3JH4eH3,5¼12.6), 3.91 (d, 3H, OCH3, 3JOCH3eP¼12.6), 7.06e7.12 (m,
3.0e3.1 (m, 3H, H1,3), 3.2e3.3 (m, 2H, H5), 7.2e7.4 (m, 5H, Harom); 13
C
2H, Harom), 7.17e7.29 (m, 3H, Harom), 7.66e8.08(m, 5H, Harom); 31P
NMR (CDCl3,100 MHz)
(s, Cpara), 127.8 (s, Cortho), 129.0 (s, Cmeta), 141.5 (s, Cipso). HRMS (EI)
calcd for C11H14Br2: 306.0369; found: 305.9445.
d
31.7 (s, C2,4), 39.4 (s, C1,5), 42.9 (s, C3), 127.2
NMR(CDCl3, 81 MHz)
372.1395; found: 372.1419. Compound 11b was obtained in a simi-
d
þ79.05. HRMS (EI) calcd for C18H22BF4OP:
lar manner yielding 0.23 g (80%) of the product as a white solid, mp
148e150 ꢀC. 1H NMR (CDCl3, 200 MHz)
d 1.14e1.30 (m, 2H, H2,6ax,
4.1.2. 1,1,4-Triphenylphosphorinanium bromide (9). A mixture of
2.37 g (7.70 mmol) of 3-phenyl-1,5-dibromopentane and 1.37 mL
(10.2 mmol) of trimethylsilyl (diphenylphosphine) in 25.0 mL of
anhydrous toluene was heated under reflux for 30 h period. The
mixture was cooled to room temperature, and the white precipitate
formed was collected by filtration, the process yielded 1.78 g (56%)
of 9 as a white solid, mp 174e176 ꢀC. 1H NMR (CD3OD, 400 MHz)
3JH2,6axeH3,5ax¼15.0), 2.00e2.30 (m, 4H, H2,6,3,5eq), 2.35e2.60 (m,
3
2H, H3,5ax), 2.78e2.81 (m, 1H, H4, JH4eH3,5ax¼15.0), 3.88 (d, 3H,
3
OCH3, JOCH3eP¼12.6), 7.18e7.40 (m, 5H, Harom), 7.43e7.75 (m, 3H,
Harom), 7.80e8.00 (m, 2H, Harom); 31P NMR (CDCl3, 81 MHz)
d
þ79.44. HRMS (EI) calcd for C18H22BF4OP: 372.1395; found:
372.1403.
d
1.86e1.98 (m, 2H, H2,6), 2.38e2.50 (dd, 2H, H2,6, 3JH2,6-H3,5¼15.0),
4.1.5. Base-induced substitution reaction of 1-methoxy-cis-1,4-di-
phenylphosphorinanium
3
3.10e3.20 (m, 3H, H3,5,4), 3.46e3.53 (t, 2H, H3,5 JH3,5eH2,6¼15.0),
7.14e7.30 (m, 5H, Harom), 7.66e7.97 (m, 8H, Harom), 8.15e8.20
tetrafluoroborate
(11a). To
0.30 g
(0.81 mmol) of salt 11a was added a 1.0 M solution of sodium hy-
droxide at room temperature. The mixture was stirred at room
temperature for 1 h and then refluxed for an additional 2 h. The
mixture was allowed to cool to room temperature and then
extracted with dichloromethane. The organic layers were com-
bined, dried over sodium sulfate and the solvent evaporated to
yield 0.19 g of a mixture of the corresponding phosphorinane
oxides. Analysis of the 31P NMR signals of the mixture showed 62%
of 10a and 38% of 10b, both compounds previously characterized.
The same procedure was used as for the reaction of the 11b isomer
with similar results, yielding 0.12 g of a mixture of the corre-
sponding phosphorinane oxides. Analysis of the 31P NMR signals of
the mixture showed a 75% of 10b and 25% of 10a, both compounds
previously characterized.
(m, 2H, Harom); 13C NMR (CD3OD, 100 MHz)
d 20.21 (d, C2,6,
1JC2,6eP¼50.1), 30.11 (d, C3,5, 2JC3,5eP¼6.1), 43.65 (d, C4, 3JC4eP¼6.1),
127.61 (s, Cortho), 128.10 (s, Cmeta), 129.86 (s, Cpara), 131.30 (d, Cortho
,
,
2JCeP¼12.2), 132.05 (d, Cmeta
,
3JCmetaeP¼12.2), 132.94 (d, Cpara
4JCparaeP¼10.6), 136.12 (d, Cipso, 1JCipsoeP¼45.6), 145.60 (s, Cipso); 31P
NMR (CD3OD, 81 MHz)
d
þ29.4. HRMS (EI) calcd for C23H24BrP:
411.3212; found: 411.3372.
4.1.3. 1-Oxo-1,4-diphenylphosphorinane(10). Exactly 1.7 g (4.13
mmol) of the bromide phosphorinanium salt 9 and 15.0 mL of
a 20% solution of sodium hydroxide were heated under reflux
overnight. The reaction mixture was allowed to cool to room
temperature and was extracted with dichloromethane; the com-
bined organic layers were dried over sodium sulfate and the solvent
evaporated to afford 1.2 g (95%) as a 70:30 isomeric mixture of the
4.1.6. Base substitution reaction of 1-methoxy-trans-1,4-diphenyl-
phosphorinanium 11b with 17O-enriched sodium hydroxide. Exactly
0.03 mL of a 1.0 M solution of Na17OH (prepared by adding 7.00 mg
of Naꢀ to 6.0 mg of 35% H217O) was added to 0.047 g (0.125 mmol) of
salt 11b as previously described for base-induced substitution re-
actions of 11a and 11b. The reaction was finished and 0.024 g (71%)
product. 31P NMR (CDCl3):
d
þ34.1,
d
þ31.1. The diastereomeric
mixture of 10a and 10b were separated through a chromatographic
column (silica gel) using a 95:5 mixture of dichloromethane/iso-
propanol as eluent. Compound (10a): 0.62 g (52%), mp 125e127 ꢀC.
1H NMR (CDCl3, 400 MHz)
d 1.70e1.85 (m, 2H, H3,5ax), 2.14e2.42 (m,
4H, H3,5,2,6eq), 2.67 (dd, 2H, H2,6ax, 3JH2,6ax-3,5ax¼15.6), 2.82 (dd, 1H,
4ax, 3JH4axeH3,5ax¼11.6), 7.09e7.12 (m, 1H, H16para), 7.17e7.29 (m, 4H,
H14,18ortho, H15,17meta), 7.55e7.62 (m, 3H, H8,12ortho, H10para), 7.80e7.85
of the 17O-enriched oxide products 10a and 10b were obtained. 17
O
NMR (CDCl3, 40 MHz)
d 28.08, d 55.44. HRMS (EI) calcd for
C17H1917OP: 271.1248; found: 271.1285.
(m, 2H, H9,11meta); 13C NMR (CDCl3 100 MHz)
d 26.9 (d, C2,6,
1JCeP¼63.5), 31.1 (d, C3,5
,
2JCeP¼3.0), 43.7 (d, C4, JCeP¼6.0), 126.7
3
Acknowledgements
(s, C16para), 126.9 (s, C14,18ortho), 128.8 (s, C9,11,15,17meta), 129.5 (d,
C8,12ortho
,
2JCeP¼11.0), 130.2 (d, C7ipso,1JCeP¼9.0), 132.6 (s, C10para),
The authors thank CONACyT of México (82129) for financial
support of this work. Araceli Medina Arreguin thanks PROMEP
(UAEMOR-CA-33) for a Graduate Scholarship. Susana López Cortina
thanks Karla Treviño Romero for her technical help in some syn-
thetic experiments.
144.7 (s, C13ipso); 31P NMR (CDCl3, 81 MHz)
d
þ34.60. Anal. Calcd for
C17H19OP: C, 75.53; H, 7.08. Found: C, 75.81; H, 7.17. Compound
(10b): 0.41 g (35%), mp 183e186 ꢀC. 1H NMR (CDCl3, 400 MHz)
d
1.95e2.06 (m, 2H, H2,6ax), 2.10e2.30 (m, 4H, H2,6,3,5eq), 2.38e2.51
3
(m, 2H, H3,5ax), 2.74 (dd, 1H, H4, JH4axeH3,5ax¼12.0), 7.20e7.36
(m, 5H, H14,18ortho, H16para, H15,17meta,), 7.50e7.60 (m, 3H, H8,12ortho,
Supplementary data
H10para), 7.70e7.90 (m, 2H, H9,11meta); 13C NMR (CDCl3, 400 MHz)
1
d
28.35 (d, C2,6, JCeP¼65.3), 28.95 (d,C3,5
,
2JCeP¼4.5), 45.26 (s, C4),
Supplementary data associated with this article can be found in
126.79 (s, C16para), 126.86 (s, C14,18ortho), 128.78 (s, C9,11,15,17meta),
2
1
128.90 (d, C8,12ortho JCeP¼12.1), 130.34 (d, C7ipso JCeP¼36.4), 132.39
(s, C10para), 145.58 (s, C13ipso); 31P NMR (CDCl3, 81 MHz)
d
þ31.99.
References and notes
Anal. Calcd for C17H19OP: C, 75.53; H, 7.08. Found: C, 75.77, H, 7.11.
1. Kumara Swamy, K. C.; Satish Kumar, N. Acc. Chem. Res. 2006, 39, 324.
2. (a) Ye, L. W.; Zhou, J.; Tang, Y. Chem. Soc. Rev. 2008, 37, 1140; (b) Martin, R.;
Buchwald, S. L. Acc. Chem. Res. 2008, 41, 1461; (c) Trost, B. M.; Machacek, M. R.;
4.1.4. cis- and trans-1-Methoxy-1,4-diphenylphosphorinanium tet-
rafluoroborates, (11a and 11b). Exactly 0.287 g (1.06 mmol) of