Phosphine 10: [α]D = ϩ15.6 (c = 0.5, CHCl3); anal. calcd for
organic layers were washed with brine. After drying over
C30H33NO4PReSi: C, 50.26; H, 4.64; N, 1.95; found: C, 50.16;
MgSO4 and evaporation of the solvent, the residue was purified
by column chromatography (silica gel). Elution with petroleum
ether–diethyl ether (9 : 1) afforded phosphine 5 (135 mg, 70%)
as a white solid.
H, 4.66; N, 1.71%; IR (CHCl3): ν˜
/cmϪ1 = 3055, 2958, 2025,
1
1934, 1660; H NMR: δ 0.24 (s, 9H, CH3), 0.51 (s, 9H, CH3),
3.81 (dd, 1H, J = 7.5 and 10.3 Hz, CH2), 3.92–4.01 (m, 2H, CH
and CH2), 4.70 (m, 1H, Cp–H), 5.19 (m, 1H, Cp–H), 7.16–7.39
(m, 10H, Ph–H); 13C NMR: δ 0.00 (SiCH3), 24.64 (CH3), 28.90
(C), 32.73 (C), 67.52 (CH2), 75.46 (CH), 91.39 (Cp–CH), 92.50
(d, J = 4.8 Hz, Cp–CH), 95.95 (Cp–C), 101.36 (d, J = 14.4 Hz,
Cp–C), 102.71 (d, J = 28.2 Hz, Cp–C), 127.30 (d, J = 7.1 Hz,
Ph–CH), 127.35 (Ph–CH), 127.53 (d, J = 7.2 Hz, Ph–CH),
128.46 (Ph–CH), 131.10 (d, J = 19.8 Hz, Ph–CH), 134.17
(d, J = 21.5 Hz, Ph–CH), 135.59 (d, J = 14.4 Hz, Ph–C), 137.73
(d, J = 10.7 Hz, Ph–C), 157.56 (d, J = 3.6 Hz, C), 192.22 (CO);
31P NMR: δ Ϫ15.66; MS m/z (rel%) = 717 (Mϩ, 41), 689 (81),
660 (100), 605 (74).
Method B: removal of TMS group from compound 10. Com-
pound 5 (249 mg, 68%) was also prepared by removing the
TMS group from compound 10 (408 mg, 0.57 mmol), using the
same method as described above for the transformation from 11
to 12. The analytical data of 5 from the two methods are in
accordance.
Mp: 151 ЊC (dec.); [α]D = ϩ63.4 (c = 0.5, CHCl3); anal. calcd
for C27H25NO4PRe: C, 50.30; H, 3.91; N, 2.17; found: C, 50.50;
H, 4.04; N, 2.00%; IR (KBr): ν˜
/cmϪ1 = 3438, 2956, 2028, 1926,
1
1664; H NMR: δ 0.54 (s, 9H, CH3), 3.78 (dd, 1H, J = 8.6 and
8.3 Hz, CH2), 3.92–4.02 (m, 2H, CH and CH2), 4.61 (m,
1H, Cp–H), 5.16 (m, 1H, Cp–H), 6.01 (m, 1H, Cp–H), 7.22–
7.34 (m, 10H, Ph); 13C NMR: δ 25.82 (CH3), 34.21 (C), 69.04
(CH2), 76.35 (CH), 82.92 (Cp–CH), 90.49 (Cp–CH), 92.42
(d, J = 5.3 Hz, Cp–CH), 94.41 (Cp–C), 101.66 (d, J = 10.7 Hz,
Cp–C), 128.59 (Ph–CH), 128.71 (d, J = 4.2 Hz, Ph–CH),
128.87 (d, J = 6.6 Hz, Ph–CH), 129.69 (Ph–CH), 132.65 (d,
J = 19.7 Hz, Ph–CH), 133.65 (d, J = 20.3 Hz, Ph–CH), 136.10
(d, J = 12.0 Hz, Ph–C), 138.28 (d, J = 11.4 Hz, Ph–C), 159.13
(C), 192.72 (CO); 31P NMR: δ Ϫ15.99; MS m/z (rel%) =
645 (Mϩ, 46), 617 (100), 560 (19), 483 (20).
Phosphine oxide 11: mp 62 ЊC; [α]D = Ϫ38.4 (c = 0.5, CHCl3);
anal. calcd for C30H33NO5PReSi: C, 49.17; H, 4.54; N, 1.91;
found: C, 49.74; H, 5.07; N, 1.65%; IR (KBr): ν˜
/cmϪ1 = 3420,
1
2956, 2028, 1929, 1665; H NMR: δ 0.01 (s, 9H, CH3), 0.44
(s, 9H, CH3), 3.15 (dd, 1H, J = 10.1 and 10.1 Hz, CH2), 3.42–
3.54 (m, 2H, CH and CH2), 5.08 (m, 1H, Cp–H), 5.38 (m,
1H, Cp–H), 7.10–7.27 (m, 6H, Ph–H), 7.45–7.52 (m, 2H,
Ph–H), 7.62–7.70 (m, 2H, Ph–H); 13C NMR: δ 0.00 (CH3),
25.25 (CH3), 26.18 (C), 32.51 (C), 67.95 (CH2), 75.89 (CH),
91.33 (d, J = 10.8 Hz, Cp–CH), 94.18 (d, J = 13.2 Hz, Cp–C),
95.54 (d, J = 11.3 Hz, Cp–CH), 100.10 (d, J = 10.77 Hz, Cp–C),
103.69 (d, J = 36.9 Hz, Cp–C), 127.01 (d, J = 13.2 Hz, Ph–CH),
127.36 (d, J = 12.5 Hz, Ph–CH), 130.69 (d, J = 3.0 Hz, Ph–CH),
130.92 (d, J = 3.0 Hz, Ph–CH), 131.30 (d, J = 5.3 Hz, Ph–CH),
131.43 (d, J = 6.0 Hz, Ph–CH), 133.59 (d, J = 32.7 Hz, Ph–C),
135.67 (d, J = 28.1 Hz, Ph–C), 155.16 (C), 191.02 (CO); 31P
NMR: δ 23.64; MS m/z (rel%) = 733 (Mϩ, 62), 705 (100).
(S,Sp)-2-[2-(Diphenylselenophosphinoyl)ferrocenyl]-4-tert-butyl-
4,5-dihydro-1,3-oxazole (13)
Compound 13 was prepared by stirring ferrocenylphosphine 2
(119 mg, 0.2 mmol) with selenium (158 mg, 2 mmol) in CHCl3
(2 mL) at room temperature for 10 min. After filtration of the
excess of selenium under Ar, the solvent was removed under
vacuum. The resulting product (yellow solid) was directly used
for the spectroscopical analysis. Mp: 172 ЊC (dec.); [α]D = ϩ52.0
(c = 0.25, CHCl3); anal. calcd for C29H30FeNOPSe: C, 60.65; H,
5.26; N, 2.44; found: C, 58.89; H, 5.50; N, 2.16%; IR (KBr):
(S,Rp)-2-[2-(Diphenylphosphinoyl)cyrhetrenyl]-4-tert-butyl-4,5-
dihydro-1,3-oxazole (12)
To a solution of 11 (700 mg, 0.95 mmol) in THF (5 mL) was
added TBAF (5 mL of a 1 M solution in THF), the resulting
mixture was stirred at room temperature for 5 min. After
removal of the solvent in vacuo, the residue was purified by
column chromatography (silica gel). Elution with petroleum
ν˜
/cmϪ1 = 3449, 2955, 1664; 1H NMR: δ 0.70 (s, 9H, CH3), 3.57
(br m, 2H, CH2), 3.97 (br m, 2H, CH and Cp–H), 4.41 (br s, 6H,
Cp–H), 5.00 (m, 1H, Cp–H), 7.24–7.40 (m, 6H, Ph), 7.66–7.79
(m, 4H, Ph); 13C NMR: δ 26.33 (CH3), 33.97 (C), 68.58 (CH2),
72.44 (5 Cp–CH), 76.54 (CH), 82.92 (Cp–CH), 90.49 (Cp–
CH), 92.42 (d, J = 5.3 Hz, Cp–CH), 94.41 (Cp–C), 101.66
(d, J = 10.7 Hz, Cp–C), 129.02 (d, J = 12.6 Hz, Ph–CH), 128.23
(d, J = 11.9 Hz, Ph–CH), 131.05 (Ph–CH), 131.06 (Ph–CH),
132.43 (d, J = 10.2 Hz, Ph–CH), 132.83 (d, J = 10.8 Hz,
Ph–CH), 136.10 (d, J = 12.0 Hz, Ph–C), 138.28 (d, J = 11.4 Hz,
Ph–C), 159.13 (C), 192.72 (CO); 31P NMR: δ 35.26 (J = 325.0
Hz); MS m/z (rel%) = 574 (Mϩ, 14), 511 (100), 454 (23), 410
(68).
ether–ethyl acetate (1 : 1
0 : 1) afforded compound 12
(251 mg, 40%) as a white solid. Mp: 158 ЊC (dec.); [α]D = Ϫ21.7
(c = 0.52, CHCl3); anal. calcd for C27H25NO5PRe: C, 49.08; H,
3.81; N, 2.12; found: C, 49.19; H, 3.67; N, 2.00%; IR (KBr):
ν˜
/cmϪ1 = 3438, 2956, 2028, 1926, 1664; 1H NMR: δ 0.62 (s, 9H,
CH3), 3.55–3.65 (m, 2H, CH and CH2), 3.88 (dd, 1H, J = 7.1
and 7.7 Hz, CH2), 5.26 (m, 1H, Cp–H), 5.45 (m, 1H, Cp–H),
5.95 (m, 1H, Cp–H), 7.35–7.48 (m, 6H, Ph), 7.67–7.73 (m, 2H,
Ph), 7.76–7.82 (m, 2H, Ph); 13C NMR: δ 25.96 (CH3), 34.13 (C),
69.30 (CH2), 76.39 (CH), 83.08 (d, J = 9.2 Hz, Cp–CH), 89.87
(d, J = 6.9 Hz, Cp–CH), 94.23 (Cp–C), 97.29 (d, J = 10.7 Hz,
Cp–C), 97.39 (d, J = 10.7 Hz, Cp–CH), 128.29 (d, J = 13.0 Hz,
Ph–CH), 128.62 (d, J = 12.2 Hz, Ph–CH), 132.01 (d, J = 9.9 Hz,
Ph–CH), 132.03 (d, J = 19.8 Hz, Ph–C), 132.05 (d, J = 3.8 Hz,
Ph–CH), 132.23 (d, J = 3.1 Hz, Ph–CH), 132.47 (d, J = 13.7 Hz,
Ph–CH), 133.10 (d, J = 25.2 Hz, Ph–C), 157.29 (C), 191.26
(CO); 31P NMR: δ 23.21; MS m/z (rel%) = 661 (Mϩ, 74),
632 (100), 575 (50), 520 (19).
(S,Sp)-2-[2-(Diphenylselenophosphinoyl)cyrhetrenyl]-4-tert-
butyl-4,5-dihydro-1,3-oxazole (14)
Compound 14 was obtained as a white solid in the same way as
compound 13, except for a higher excess of selenium (50 equiv.)
and longer reaction time (3 h). Mp: 82 ЊC (dec.); [α]D = Ϫ11.0
(c = 1.0, CHCl3); anal. calcd for C27H25NO4PReSe: C, 44.81; H,
3.48; N, 1.94; found: C, 45,92; H, 4.27; N, 1.61%; IR (KBr):
1
ν˜
/cmϪ1 = 3449, 2958, 2013, 1894; H NMR (d8-toluene): δ 0.44
(S,Rp)-2-[2-(Diphenylphosphino)cyrhetrenyl]-4-tert-butyl-4,5-
dihydro-1,3-oxazole (5)
(s, 9H, CH3), 3.05 (dd, 1H, J = 9.2 and 9.2 Hz, CH2), 3.18 (dd,
1H, J = 9.2 and 8.4 Hz, CH), 3.31 (dd, 1H, J = 8.4 and 8.2 Hz,
CH2), 4.00 (m, 1H, Cp–H), 4.95 (m, 1H, Cp–H), 5.13 (m, 1H,
Cp–H), 6.70–6.85 (m, 6H, Ph), 7.61–7.80 (m, 4H, Ph); 13C
NMR (d8-toluene): δ 25.87 (CH3), 33.44 (C), 68.74 (CH2), 76.45
(CH), 82.11 (d, J = 9.0 Hz, Cp–CH), 88.33 (d, J = 5.9 Hz,
Cp–CH), 98.38 (d, J = 12.0 Hz, Cp–C), 100.19 (Cp–C), 106.00
(Cp–C), 127.06 (d, J = 13.8 Hz, Ph–CH), 127.30 (d, J = 12.0 Hz,
Ph–C), 127.47 (d, J = 13.0 Hz, Ph–CH), 127.80 (d, J = 12.2 Hz,
Method A: reduction of phosphine oxide 12. To a solution of
phosphine oxide 12 (198 mg, 0.3 mmol) in THF (2 mL) were
added PMHS (1.4 mL) and Ti(OiPr)4 (0.8 mL). The solution
was degassed and refluxed for 30 min. After cooling to
room temperature, the reaction mixture was poured into water
(20 mL) and the organic layer was separated. The aqueous layer
was extracted with hexane (3 × 50 mL), and the combined
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 4 5 – 1 5 2
150