1,2-Oxaphosphinines as Ligands in Homogeneous Catalysis
1
6
-Chloro-6H-dinaphtho[c,e][1,2]oxaphosphinine (7a): Lithium
0.2); yield 0.51 g (71%). H NMR (300 Hz, CDCl
m, 3 H, BH ), 2.33 (s, 3 H, CH ), 2.37 (s, 3 H, CH
4 H, Ar), 7.33–7.54 (m, 4 H, Ar), 7.78–8.01 (m, 4 H, Ar) ppm.
NMR (125 Hz, CDCl ): δ = 120.2 (q, d, J = 10.5 Hz), 120.3, 125.5,
3
): δ = 1.17 (br.
(0.054 g, 7.7 mmol) was added to a solution of dinaphtho[2,1-b;
3
3
3
), 7.01–7.28 (m,
1
3
1
Ј,2Ј-d]furan (5, 0.537 g, 2.00 mmol) in diethyl ether (30 mL) and
C
the reaction mixture was stirred for 48 h at room temperature. The
resulting red-brown suspension was filtered and the solution was
added dropwise at 0 °C to a solution of PCl (0.288 g, 2.10 mmol)
3
in diethyl ether (10 mL). The reaction mixture was stirred for 2 h
at room temperature and the solvent was then evaporated under
reduced pressure. The residue was transferred into toluene (10 mL),
and the solution was filtered through a short column of celite to
give 6-chloro-6H-dinaphtho[c,e][1,2]oxaphosphinine (6) as a light
yellow foam (0.57 g, 85%). H NMR (300 Hz, CDCl
7
3
125.7, 126.3, 126.5, 126.7, 127.1, 128.3, 128.6, 128.8, 128.9, 129.4,
129.6, 130.3 (q), 131.3 (q), 131.5 (q), 131.9, 134.9 (q), 135.9 (q),
3
1
138.2 (q), 150.1 (d, J = 12.9 Hz, q, C–O) ppm. P NMR (121 Hz,
CDCl ): δ = 94.7 (br. m) ppm. MS (EI, 70 eV): m/z (%) = 343 (55)
[M – BH
3
+
+
3
3 2
] , 299 (100) [M – BH – NMe ] . C22H21BNOP (M =
357.19): calcd. C 74.00, H 5.93, N 3.92, P 8.67; found C 75.00, H
6.12, N 2.73, P 8.01.
1
3
): δ = 7.17–
6
-Phenyl-6H-dinaphtho[c,e][1,2]oxaphosphinine–Borane Complex
.28 (m, 3 H, Ar), 7.34–7.69 (m, 5 H, Ar), 7.75–7.98 (m, 4 H,
13
8c: A suspension of lithium (0.10 g, 14.3 mmol) was added to a
solution of dinaphtho[2,1-b:1Ј,2Ј-d]furan (5, 1.00 g, 3.73 mmol) in
diethyl ether (60 mL). The resulting red-brown suspension was
stirred for 48 h at room temperature. The solution was then added
Ar) ppm. C NMR (125 Hz, CDCl
3
): δ = 119.0, 120.5, 124.8,
1
1
25.6, 126.2, 126.5, 127.7, 128.0, 128.4, 128.7, 128.8, 128.9, 129.0,
3
1
31.2, 131.4, 131.6, 136.4, 149.5 (d, J = 6.5 Hz, q, C–O) ppm.
): δ = 131.7 ppm. MS (CI, isobutane): m/z
%) = 299 (43) [M – Cl], 271 (100), 207 (39).
P
NMR (121 Hz, CDCl
(
3
dropwise at 0 °C to a solution of PhPCl
diethyl ether (30 mL). The reaction mixture was stirred at room
(7b): temperature for 12 h, a solution of BH ·Me S (2 in toluene,
2.5 mL, 4.96 mmol) was added, and the resulting solution was
2
(0.51 mL, 3.76 mmol) in
6
-Dimethylamino-6H-dinaphtho[c,e][1,2]oxaphosphinine
3
2
DABCO (1,4-diazabicyclo[2,2,2]octane, 0.083 g, 0.74 mmol) was
added to a solution of 6-dimethylamino-6H-dinaphtho[c,e][1,2]oxa-
phosphinine–borane complex 8b (0.20 g, 0.56 mmol) in THF
stirred for an additional 3 h at room temperature. The solvent was
evaporated, and the residue was dried under vacuum. The crude
product was purified by column chromatography (silica gel, tolu-
(
(
15 mL). The mixture was stirred at room temperature for 11 h
progress of the reaction was monitored by P NMR). The solvent
31
f
ene/n-heptane 1:2; R = 0.3). Compound 8c was isolated as a white
1
was evaporated and the product was purified on a short column of
celite (toluene) to give pure compound 7c (131 mg, 68%) as a
colourless oil. H NMR (300 Hz, CDCl
solid (1.15 g, 80%). H NMR (300 Hz, CDCl
H, BH ), 7.02–7.36 (m, 5 H, Ar), 7.39–7.46 (m, 3 H, Ar), 7.50–7.58
(m, 2 H, Ar), 7.68–7.73 (m, 2 H, Ar), 7.94–8.07 (m, 3 H, Ar) ppm.
3
): δ = 1.18 (br. m, 3
3
1
3
): δ = 2.88 (s, 3 H, CH
), 7.05–7.28 (m, 4 H, Ar), 7.34–7.52 (m, 4 H, Ar),
.78–8.01 (m, 4 H, Ar) ppm. 13C NMR (125 Hz, CDCl
): δ = 120.1, 126.6, 127.0, 127.2, 127.3, 128.5, 128.7, 128.8, 128.9, 129.0, 129.2,
3
),
1
3
2
7
1
1
1
.93 (s, 3 H, CH
3
3
C NMR (125 Hz, CDCl ): δ = 120.1, 120.5, 120.6, 125.5, 126.3,
3
20.2, 125.4, 125.6, 126.3, 126.4, 126.6, 127.1, 128.2, 128.6, 128.8,
28.9, 129.4, 129.6, 130.4 (q), 131.5 (q), 131.5 (q), 131.9, 134.9 (q),
129.6, 129.8, 130.3, 130.4, 131.3, 131.7, 131.8, 132.0, 132.7, 134.3,
3
1
136.5, 136.6, 150.3 (d, J = 14.1 Hz, q, C–O) ppm. P NMR
): δ (121 Hz, CDCl ): δ = 98.4 (br. d, J = 62 Hz) ppm. MS (EI, 70 eV):
m/z (%) = 376 (100) [M – BH +
H12] , 149
35.9 (q), 139.3 (q), 151.2 (q) ppm. 31P NMR (121 Hz, CDCl
3
3
+
=
92.6 ppm.
3
] , 297 (60), 252 (50) [C20
10). MS (CI, isobutane): m/z (%) = 389 (40) [M – H], 377 (90)
M – BH ], 299 (100) [M – BH – Ph]. HRMS (EI) calcd. for
20OBP [M – BH 376.1012; found 376.1017.
(
[
C
6-Phenyl-6H-dinaphtho[c,e][1,2]oxaphosphinine (7c): DABCO (1,4-
2
3
diazabicyclo[2,2,2]octane, 0.04 g, 0.35 mmol) was added to a solu-
tion of 6-phenyl-6H-dinaphtho[c,e][1,2]oxaphosphinine–borane
complex 8c (0.10 g, 0.26 mmol) in THF (10 mL). The mixture was
stirred at room temperature for 12 h (the progress of the reaction
was monitored by 31P NMR). The solvent was evaporated and the
product was purified on a short column of celite (toluene) to give
+
26
H
3
]
6-Phenoxy-6H-dinaphtho[c,e][1,2]oxaphosphinine (9a): A mixture of
phenol (0.071 g, 0.75 mmol) and triethylamine (0.114 g, 0.157 mL,
1.123 mmol), dissolved in toluene (8 mL), was added dropwise at
0 °C to a stirred solution of 6-chloro-6H-dinaphtho[c,e][1,2]oxa-
phosphinine (7a, 0.250 g, 0.75 mmol) in toluene (8 mL). The reac-
tion mixture was allowed to warm to room temperature, stirred for
12 h and then filtered. The solvent was evaporated in vacuo and
1
pure compound 7c (60 mg, 60%) as a colourless foam. H NMR
(300 Hz, CDCl
3
): δ = 6.88–7.01 (m, 3 H, Ar), 7.08–7.30 (m, 6 H,
Ar), 7.37–7.51 (m, 3 H, Ar), 7.56–7.65 (m, 2 H, Ar), 7.76–7.97 (m,
3
6
1
1
1
H, Ar) ppm. 13C NMR (125 Hz, CDCl
3
): δ = 120.2 (q, d, J =
the residue was purified by column chromatography (silica gel, tol-
1
Hz), 120.4, 124.1, 125.5, 125.6, 126.8, 127.6, 127.8, 127.9, 128.1,
28.4, 128.6, 129.6, 130.0, 130.2 (q), 130.6 (q), 130.6 (q), 131.1 (q),
31.5, 131.8, 134.2 (q), 134.4 (q), 135.3 (q), 136.4 (q), 136.8 (q),
uene; R
CDCl
f
= 0.93) to give 9a (0.179 g, 61%). H NMR (250.1 MHz,
): δ = 6.54–6.64 (m, 1 H, arom. H), 6.79 (d, J = 8.7 Hz, 2
H, arom. H), 6.84–7.37 (m, 8 H, arom. H), 7.48 (d, J = 8.1 Hz, 2
H, arom. H), 7.63 (d, J = 8.7 Hz, 1 H, arom. H), 7.75–7.95 (m, 3
3
53.2 (d, J = 9.4 Hz, q, C–O) ppm. 31P NMR (121 Hz, CDCl
): δ
3
1
3
=
92.0 ppm.
H, arom. H) ppm. C NMR (62.9 MHz, CDCl
3
): δ = 118.9 (q),
19.8, 120.2, 121.2 (q), 123.7, 124.5, 125.5, 125.6, 126.3, 126.4,
27.2, 127.4, 128.1–128.3 (2ϫarom. C), 128.4, 128.7, 129.3–129.4
1
1
6
-Dimethylamino-6H-dinaphtho[c,e][1,2]oxaphosphinine–Borane
Complex 8b: Lithium (0.054 g, 7.70 mmol) was added to a solution
of dinaphtho[2,1-b;1Ј,2Ј-d]furan (5, 0.537 g, 2.00 mmol) in diethyl
ether (30 mL). The resulting red-brown suspension was stirred for
(
(
1
2ϫarom. C), 130.0 (q), 130.2 (q), 130.5, 133.4 (q), 133.6 (q), 135.8
q), 149.2 (q), 155.3 (q) ppm. P NMR (125 Hz, CDCl
25.5 ppm. MS (EI, 70 eV): m/z (%) = 392 (28) [M] , 299 (100)
31
3
): δ =
+
4
8 h at room temperature. The mixture was added dropwise at 0 °C
to a solution of Me NPCl (prepared by the procedure of Nöth
0.150 g, 2.10 mmol) in diethyl ether (10 mL). The
reaction mixture was stirred at room temperature for 2 h, a solution
of BH ·Me S (2 in toluene, 2.60 mmol, 1.30 mL) was then added,
+
6 4
[M – OC H ] , 252 (33).
2
2
[
19]
and Vetter,
6-[2,4-Bis(tert-butyl)phenoxy]-6H-dinaphtho[c,e][1,2]oxaphosphinine
(9b): A mixture of 2,4-bis(tert-butyl)phenol (0.155 g, 0.75 mmol)
and triethylamine (0.114 g, 0.157 mL, 1.123 mmol), dissolved in
toluene (10 mL), was added dropwise at 0 °C to a stirred solution
of the 6-chlorooxaphosphinine 7a (0.250 g, 0.75 mmol) in toluene
(8 mL). The reaction mixture was allowed to warm to room tem-
perature, stirred overnight at ambient temperature and then fil-
3
2
and the resulting solution was stirred for a further 2 h at room
temperature. The solvent was evaporated, and the residue was dried
under vacuum. The product 8b (light yellow solid) was purified by
f
column chromatography (silica gel, toluene/n-heptane 1:1, R =
Eur. J. Org. Chem. 2010, 1669–1680
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
1677