(10R,11R)-10,11-Dimethoxy-10,11-dihydro-5-propyl-5H-
dibenzo[b,f ]phosphepine 5-oxide 34. (1R,2R)-1,2-Bis(2-bromo-
phenyl)-1,2-dimethoxyethane 17 (408 mg, 1.02 mmol) was
reacted by method C. A solution of 1:1 hexane–Et2O was used
as eluent for purification of the phosphine, Rf(hexane–Et2O,
1:1) 0.49. Flash chromatography, eluting with 5% methanol in
EtOAc yielded the phosphine oxide (15.1 mg, 5%) as an oil,
Rf(methanol–EtOAc, 1:19) 0.37; νmax (CHCl3)/cmϪ1 2826
31.8Ϫ (1JPC 72.0), 27.4ϩ (CMeA), 26.7ϩ (CMeB), 15.5ϩ (3JPC 15.6,
PCH2CH2Me) and 15.0Ϫ (PCH2CH2).
(10R,11R)-10,11-Bis[(1,1-dimethylethyl)dimethylsiloxy]-
10,11-dihydro-5-propyl-5H-dibenzo[b,f ]phosphepine 5-oxide 39.
(1R,2R)-1,2-Bis(2-bromophenyl)-1,2-bis[(1,1-dimethylethyl)-
dimethylsiloxy]ethane 13 (587 mg, 0.978 mmol) was reacted by
method C. A solution of 9:1 hexane–Et2O was used as eluent
for purification of the phosphine, Rf(hexane–Et2O, 9:1) 0.61.
Flash chromatography, eluting with EtOAc yielded the phos-
phine oxide (127 mg, 24%) as waxy plates, mp 103–105 ЊC (from
hexane), Rf(EtOAc) 0.51; νmax (CHCl3)/cmϪ1 1592 (Ar), 1578
(O–Me), 1602 (Ar), 1158 (P᎐O) and 1101 (C–O); δ (400 MHz;
᎐
H
3
CDCl3) 8.36 (1 H, ddd, JPH 12.2, J 5.2 and 3.8, 4 or 6-ArH),
8.31–8.26 (1 H, m, 4 or 6-ArH), 7.54–7.48 (4 H, m), 7.41–7.34
(2 H, m), 4.76 (d, J 7.7, ArCHACHBAr), 4.73 (d, J 7.7, ArCHA-
CHBAr), 3.23 (3 H, s, OMeA), 3.04 (3 H, s, OMeB), 2.07–1.97
(2 H, m, PCH2), 1.63–1.59 (1 H, m, PCH2CHA), 1.30–1.24 (1 H,
(Ar), 1256 (P᎐O) and 1094 (C–O); δ (400 MHz; CDCl ) 8.32
᎐
H
3
(1 H, ddd, JPH 12.3, J 6.4 and 2.6, 4 or 6-ArH), 8.25 (1 H, ddd,
JPH 12.2, J 6.5 and 2.5), 7.50–7.42 (4 H, m), 7.28–7.22 (2 H, m),
5.07 (1 H, d, J 7.7, ArCHACHBAr), 5.04 (1 H, d, J 7.7, ArCHA-
CHBAr), 2.08–1.95 (2 H, m, PCH2), 1.60–1.47 (1 H, m, PCH2-
CHAHB), 1.29–1.14 (1 H, m, PCH2CHAHB), 0.82 (3 H, td, J 7.3
and JPH 1.1, CH2Me), 0.69 (9 H, s, SiACMe3), 0.42 (9 H, s,
SiBCMe3), Ϫ0.02 (3 H, s, SiMeA), Ϫ0.04 (3 H, s, SiMeB), Ϫ0.05
(3 H, s, SiMeC) and Ϫ0.40 (3 H, s, SiMeD); δC(100.6 MHz;
CDCl3) 141.0Ϫ (JPC 9.8, 9a or 11a-ArC), 140.8Ϫ (JPC 10.6, 9a or
11a-ArC), 134.1ϩ (JPC 5.9), 133.8ϩ (JPC 6.9), 133.1Ϫ (JPC 94.5, 4a
or 5a-ArC), 132.7Ϫ (JPC 91.9, 4a or 5a-ArC), 131.9ϩ (JPC 11.9),
131.3ϩ (JPC 2.4, 2 or 8-ArC), 131.2ϩ (JPC 2.2, 2 or 8-ArC),
131.0ϩ (JPC 12.4), 127.8ϩ (JPC 11.0), 127.3ϩ (JPC 10.8), 80.1ϩ
(ArCAHCBHAr), 78.0ϩ (ArCAHCBHAr), 38.4Ϫ (1JPC 72.5,
PCH2), 25.7ϩ (SiACMe3), 25.2ϩ (SiBCMe3), 18.2Ϫ (SiACMe3),
17.6Ϫ (SiBCMe3), 15.6Ϫ (2JPC 4.2, PCH2CH2), 15.3ϩ (3JPC
16.8, PCH2CH2Me), Ϫ4.5 (SiMeA), Ϫ4.6 (SiMeB) and Ϫ4.9
(SiMeC ϩ SiMeD, 2 × intensity implies 2 signals); m/z 530
(6.6%, Mϩ) and 473 (79, M Ϫ tBu) (Found: Mϩ, 530.2780.
C29H47O3PSi2 requires M, 530.2801); [α]D17 Ϫ165 (c 1.00 in
CHCl3).
4
m, PCH2CHB) and 0.86 (3 H, td, J 7.2 and JPH 1.1, CH2Me);
δC(100.6 MHz; CDCl3) 138.4Ϫ (2JPC 10.4, 9a or 11a-ArC),
137.3Ϫ (2JPC 9.7, 9a or 11a-ArC), 134.3ϩ (JPC 5.7), 133.7ϩ (JPC
6.6), 133.5Ϫ (1JPC 94.1, 4a or 5a-ArC), 132.48Ϫ (1JPC 95.4, 4a or
5a-ArC), 132.45ϩ (JPC 11.7), 131.9ϩ (JPC 12.0), 131.3ϩ (4JPC 2.3,
2 or 8-ArC), 131.1ϩ (4JPC 2.3, 2 or 8-ArC), 128.4ϩ (JPC 10.8),
128.2ϩ (JPC 10.7), 86.3ϩ (ArCAHCBHAr), 84.1ϩ (ArCAHCB-
HAr), 56.78ϩ (OMeA), 56.74ϩ (OMeB), 37.7Ϫ (1JPC 72.7, PCH2),
15.9Ϫ (2JPC 3.9, PCH2CH2) and 15.6ϩ (3JPC 16.8, CH2Me); m/z
330 (35%, Mϩ), 315 (100, M Ϫ Me) and 287 (13, M Ϫ Pr)
(Found: Mϩ, 330.1385. C19H23O3P requires M, 330.1385); [α]D17
Ϫ195 (c 1.01 in CHCl3).
(10R,11R)-10,11-Isopropylidenedioxy-10,11-dihydro-5-
propyl-5H-dibenzo[b,f ]phosphepine 5-oxide 40. (4R,5R)-2,2-
Dimethyl-4,5-bis(2-bromophenyl)-1,3-dioxolane 15 (274 mg,
0.665 mmol) was reacted by a modified method C; THF (25 ml)
was used as solvent. A solution of 9:1 hexane–Et2O was used as
eluent for purification of the phosphine, Rf(hexane–Et2O, 9:1)
0.49. Flash chromatography, eluting with EtOAc, gave the
phosphine oxide (84 mg, 37%) as an oil, Rf(EtOAc) 0.25; νmax
(CHCl3)/cmϪ1 1593 (Ar), 1166 (P᎐O) and 1133 (C–O); δ (400
᎐
H
Reactions of phosphepine oxides
MHz; CDCl3) 8.27–8.20 (2 H, m, 4 and 6-ArH), 7.81 (1 H,
dd, J 7.6 and 4.4, 1 or 9-ArH), 7.71 (1 H, dd, J 7.7 and 4.7,
1 or 9-ArH), 7.60 (1 H, tt, J 7.6, JHH 1.2 and JPH 1.2), 7.53 (1 H,
tt, J 7.5, JHH 1.4 and JPH 1.4), 7.48 (2 H, td, J 7.6 and 1.4),
5.29 (1 H, d, J 8.8, ArCHACHBAr), 4.84 (1 H, d, J 8.8, Ar-
CHACHBAr), 2.04–1.86 (2 H, m, PCH2), 1.58 (3 H, s, OMeA),
1.57 (3 H, s, OMeB), 1.58–1.48 (1 H, m, PCH2CHA), 1.34–1.26
(1 H, m, PCH2CHB), 0.85 (3 H, td, J 7.2 and 4JPH 0.9, CH2Me);
δC(62.9 MHz; CDCl3) 140.2Ϫ (2JPC 11.1, 9a or 11a-ArC),
139.3Ϫ (2JPC 9.9, 9a or 11a-ArC), 133.6ϩ (JPC 5.5), 132.70ϩ
(JPC 6.7), 132.68ϩ (2 or 8-ArC), 131.9ϩ (JPC 2.3, 2 or 8-ArC),
130.1Ϫ (1JPC 90.1, 4a or 5a-ArC), 128.0Ϫ (1JPC 89.8, 4a or
5a-ArC), 127.8ϩ (JPC 10.5), 127.7ϩ (JPC 10.5), 126.8ϩ (JPC 10.5),
123.2ϩ (JPC 10.6), 109.9Ϫ (OCO), 80.7ϩ (3JPC 0.9, 10 or 11-ArC),
79.5 (3JPC 2.3, 10 or 11-ArC), 37.6Ϫ (1JPC 71.8, PCH2), 27.1ϩ
(CMeA), 26.5ϩ (CMeB), 15.6Ϫ (2JPC 4.1, PCH2CH2) and
15.3ϩ (3JPC 15.9, CH2Me); m/z 342 (2%, Mϩ), 300 (10,
(10R,11R)-10,11-Dihydro-10,11-dihydroxy-5-phenyl-5H-
dibenzo[b,f ]phosphepine 5-oxide 41. The acetal 32 (155 mg,
0.412 mmol) and toluene-p-sulfonic acid (156 mg, 0.907 mmol)
were stirred together overnight in water (1 ml) and ethylene
glycol (5 ml) at 82 ЊC in a flask fitted with an air condenser.
Water (5 ml) was added and the mixture extracted with dichloro-
methane (5 × 5 ml). Methanol (5 ml) was added to the extract
which was dried (MgSO4) and evaporated under reduced pres-
sure. The solid was purified by flash chromatography, eluting
with EtOAc to give the diol as prisms (97 mg, 70%), mp
>130 ЊC (dec.) (from EtOH); Rf(EtOAc) 0.18; νmax (KBr)/cmϪ1
3288 (O–H), 1590 (Ar), 1437 (Ph–P) and 1159 (P᎐O);
᎐
δH(400MHz; CDCl3) 8.16 (1 H, td, J 7.8 and 1.3, 4 or 6-ArH),
8.13 (1 H, td, J 7.6 and 1.2, 4 or 6-ArH), 7.85 (1 H, dd, J 7.8 and
4.7, 1 or 9-ArH), 7.77 (1 H, dd, 7.8 and 4.8, 1 or 9-ArH), 7.63–
7.56 (2 H, m), 7.51–7.43 (3 H, m), 7.38–7.35 (2 H, m), 5.00 (1 H,
dd, J 9.7 and 3.1, HOCHACHBOH), 4.84 (1 H, dd, J 9.7 and
4.6, HOCHACHBOH), 3.54 (1 H, d, J 4.7, HOCHACHBOH)
and 3.49 (1 H, d, J 3.3, HOCHACHBOH); δC(100.6 MHz;
CD3OD)¶¶¶¶ 145.1Ϫ (JPC 11.3), 144.9Ϫ (JPC 11.8), 135.8Ϫ (1JPC
106.1), 134.2ϩ (JPC 1.7), 133.9ϩ (JPC 2.1), (133.5–133.4)ϩ,
133.2ϩ (JPC 12.2), 132.9ϩ (JPC 12.2), 131.8ϩ (JPC 11.0), 130.1Ϫ
(1JPC 102.2), 130.0ϩ (JPC 12.6), 129.1Ϫ (1JPC 98.9), 128.8ϩ (JPC
10.6), 128.6ϩ (JPC 11.1), 128.2ϩ (JPC 11.5), 77.3ϩ (CAOH) and
73.2ϩ (3JPC 2.8, CBOH); m/z 336 (11%, Mϩ), 318 (95,
M Ϫ H2O), 165 (100) and 77 (36, C6H5ϩ) (Found: Mϩ,
336.0913. C20H17O3P requires M, 336.0915); [α]D20.5 ϩ87.4
(c 0.835 in MeOH).
M Ϫ MeCH᎐CH), 299 (11, M Ϫ Pr), 284 (47, M Ϫ Me CO)
᎐
2
and 242 (100, M Ϫ MeCH᎐CH Ϫ Me CO) (Found: Mϩ,
᎐
2
342.1396. C20H23O3P requires M, 342.1385); [α]D26 ϩ90.8 (c 0.85
in CHCl3).
Phosphepine oxide 40 was also prepared by hydrolysis of the
corresponding phosphonium salt 52. Sodium hydroxide (1 ml
of a 2 solution) was added to phosphepinium iodide 52 (126
mg, 0.238 mmol) suspended in EtOH (2 ml). The mixture was
refluxed for 18 h. Ethanol was evaporated under reduced pres-
sure, water (5 ml) added and the mixture extracted with CH2Cl2
(3 × 15 ml). The combined extracts were dried (MgSO4), evap-
orated under reduced pressure and the products separated by
flash chromatography, eluting with EtOAc, to give the desired
phosphine oxide 40 (40 mg, 49%) and, from endocyclic cleav-
age, phosphine oxide 53 (10 mg, 11%), Rf(EtOAc) 0.31; δC(62.9
MHz; CDCl3) 138.9Ϫ, 136.1Ϫ, 133.4–126.5 (ϩ, several lines),
109.1Ϫ (OCO), 85.2ϩ (ArCAHCBHAr), 79.7ϩ (ArCAHCBHAr),
In another experiment, the diol 41 was prepared by the
desilylation of bis(silyl ether) 50. Tetrabutylammonium fluoride
¶¶¶¶ Data compared with 50.3 MHz spectrum to determine coupling
constants.
J. Chem. Soc., Perkin Trans. 1, 2001, 279–297
295