25.3); lmax (hexane)/nm (log e) 210 (4.40), 240 (4.18), 300 (3.07); m/z 304
(M+, 100); Found: 304.2317. Calc. for C20H33P: 304.2320. For (Z)-8:
colourless crystals, mp 37–39 °C; dH (200 MHz) 1.28 (3 H, dd, 3JPH 18.1,
3JHH 7.8, Me), 1.33 (9 H, s, p-But), 1.49 (18 H, d, 5JPH 0.6, o-But), 7.23 (1
Ar
Ar
Br
Ar
Ar
H
i, iii
P
P
C
C
P C
i, ii
Me
Me
Ar
Br
Br
(E)-8
P
C
2
3
4
H, dq, JPH 39.0, JHH 7.8, PNCH), 7.40 (2 H, d, JPH 1.0, m-Ar); dC (50
MHz) 19.7 (d, J 19.2, Me), 31.3 (p-CMe3), 32.5 (d, J 7.5, o-CMe3), 34.9
(p-CMe3), 37.9 (d, J 1.1, o-CMe3), 121.5 (d, J 1.0, m-Ar), 149.5 (p-Ar),
150.0 (d, J 62.6, i-Ar), 153.7 (d, J 1.6, o-Ar), 167.2 (d, J 41.3, PNC); dP
250.3 (dq, 2JPH 39.0, 3JPH 18.1); lmax (hexane)/nm (log e) 213 (4.39), 240
(4.20), 300 (2.92). For 9: colourless crystals, mp 280 °C (decomp.); dH (200
MHz) 1.31 (9 H, s, But), 1.39 (6 H, s, CMe2), 1.64 (9 H, s, But), 2.0–2.3 (4
H, m, CH2CH2), 2.6–4.5 (OH),†† 7.34 (1 H, dd, 4JPH 5.2, 4JHH 2.0, arom.),
7.55 (1 H, dd, 4JPH 3.7, 4JHH 2.0, arom.); dP 44.6 [t, JPH 20.6 when dH(OH)
4.5], 45.0 [br, when dH(OH) 2.6];‡‡ nmax(KBr)/cm21 1173 (PNO), 941
(P–O); m/z 322 (M+, 43), 307 (M+ 2 Me, 100). For 10: colourless oil; dH
(600 MHz) 1.30 (9 H, s, But), 1.36 (3 H, s, Me), 1.40 (3 H, s, Me), 1.61 (9
H, s, But), 1.90 (1 H, m, PCH), 2.05–2.21 (3 H, m, CHHCH2), 3.70 (3 H, d,
3JPH 10.9, OMe), 7.35 (1 H, dd, 4JPH 5.0, 4JHH 1.9, arom.), 7.55 (1 H, dd,
Br
H
Me
H
i, iii
i, ii
6
P
C
(Z)-8
Scheme 3 Reagents and conditions: i, BunLi, THF, 278 °C; ii, MeI,
278 °C; iii, MeOH, –78 °C
O
O
i
ii
4
P
OH
P OMe
4
4JPH 3.8, JHH 1.9, arom.); dC (150 MHz) 22.1 (PCH2CH2), 31.0 (CMe3),
32.3 (Me), 32.8 (CMe3), 33.3 (Me), 34.6 (d, J 5.6, PCH2), 35.1 (CMe3), 37.9
(d, J 7.3, CMe2), 38.6 (d, J 3.2, CMe3), 50.2 (d, J 6.4, OMe), 122.7 (d, J
58.0, arom., CP), 123.3 (d, J 12.0, arom., CH), 124.0 (d, J 11.5, arom., CH),
153.3 (d, J 12.1, arom.), 153.6 (arom.), 155.2 (d, J 6.3, arom.); dP 42.7; nmax
(KBr)/cm21 1213 (PNO), 1032 (P–O); m/z 336 (M+, 54), 307 (M+ 2 Me,
100); Found: 336.2216. Calc. for C20H33O2P: 336.2218.
¶ The conversion of (E)-1 to 2 might proceed in a concerted fashion
involving elimination of the chlorine atom accompanied with the migration
of the Ar group.
9
10
Scheme 4 Reagents and conditions: i, 1 m HCl aq., Et2O–EtOH (5:1), air,
room temp.; ii, CH2N2, Et2O, room temp.
(E)- and (Z)-8, shows that the phosphorus–carbon double bonds
for those are nearly perpendicular to the aromatic rings of the Ar
groups to avoid steric congestion.11 Attempted X-ray analyses
of 4, however, have been unsuccessful because of difficulties in
obtaining a suitable single crystal.
When compound 4 was allowed to react with hydrochloric
acid in Et2O–EtOH, phosphinic acid 9 was obtained in 30%
yield (Scheme 4),§ indicating that there is enough room around
the phosphorus atom for the approach of water or oxygen.††
However, attempted reaction of 4 with M(CO)5(thf) (M = Cr,
W) in THF at room temperature resulted in the decomposition
of 4, which may indicate that the end-on coordination site in 4
is blocked by the o-tert-butyl groups. Furthermore, attempted
reaction of 4 with either PtCl2(PPh3)2 and N2H4·H2O at 60 °C
for side-on coordination or Cr(CO)6 in refluxing dioxane for
p-complex formation was not successful and resulted in the
decomposition of 4.
∑ Compound 8 has already been described by Ma¨rkl and Bauer as a mixture
of (E)- and (Z)-isomers (ref. 12).
†† Compound 9 was further converted to the corresponding methyl
phosphinate 10 by the addition of a diazomethane–diethyl ether solution
(91% yield).§
‡‡ Both 31P and 1H NMR chemical shifts vary depending on the moisture
in the sample solution. In dry CDCl3, dP 44.6 and dH(OH) 4.5, whereas in
wet CDCl3, dP 45.0 and dH(OH) 2.6.
1 M. Regitz and O. J. Scherer, Multiple Bonds and Low Coordination in
Phosphorus Chemistry, Georg Thieme Verlag, Stuttgart, 1990.
2 M. Yoshifuji, I. Shima, N. Inamoto, K. Hirotsu and T. Higuchi, J. Am.
Chem. Soc., 1981, 103, 4587; 1982, 104, 6167.
3 M. Yoshifuji, K. Toyota, K. Shibayama and N. Inamoto, Tetrahedron
Lett., 1984, 25, 1809; M. Yoshifuji, K. Toyota and N. Inamoto, J. Chem.
Soc., Chem. Commun., 1984, 689. See also: H. H. Karsch, F. H. Ko¨hler
and H.-U. Reisacher, Tetrahedron Lett., 1984, 25, 3687; R. Appel,
P. Fo¨lling, B. Josten, M. Siray, V. Winkhaus and F. Knoch, Angew.
Chem., Int. Ed. Engl., 1984, 23, 619.
4 M. Yoshifuji, T. Niitsu and N. Inamoto, Chem. Lett., 1988, 1733;
M. Yoshifuji, H. Kawanami, Y. Kawai, K. Toyota, M. Yasunami,
T. Niitsu and N. Inamoto, Chem. Lett., 1992, 1053. See also: R. Appel
and M. Immenkeppel, Z. Anorg. Allg. Chem., 1987, 553, 7.
5 M. Yoshifuji, S. Ito, K. Toyota and M. Yasunami, Bull. Chem. Soc. Jpn.,
1995, 68, 1206; S. Ito, K. Toyota and M. Yoshifuji, Chem. Lett., 1995,
747; M. van der Sluis, F. Bickelhaupt, N. Veldman, H. Kooijman,
A. L. Spek, W. Eisfeld and M. Regitz, Chem. Ber., 1995, 128, 465.
6 R. Appel, C. Casser and M. Immenkeppel, Tetrahedron Lett., 1985, 26,
3551.
This work was supported in part by a Grant-in-Aid for
Scientific Research (No. 08454193) from the Ministry of
Education, Science, Sports and Culture, Japan.
Footnotes and References
* E-mail: yoshifj@mail.cc.tohoku.ac.jp
† Recipient of a Japanese Junior Scientist Fellowship from the Japan
Society for the Promotion of Science.
Attempted selective generation of (E)-3 by deprotonation of
(E)-ArPNC(H)Br with butyllithium resulted in bromine–lithium exchange
to give ArPNCH2 after quenching with water.
§ Selected spectroscopic data for 4: colourless crystals, mp 122–125 °C
(decomp.); dH (600 MHz, CDCl3) 1.34 (9 H, s, But), 1.35 (6 H, s, CMe2),
1.63 (9 H, br s, But), 2.47 (2 H, dd, 3JPH 16.9, 3JHH 6.4, CH2), 7.40 (1 H, d,
4JHH 2.0, arom.), 7.42 (1 H, dd, 4JPH 2.2, 4JHH 2.0, arom.), 8.03 (1 H, dt, 2JPH
‡
7 M. van der Sluis, J. B. M. Wit and F. Bickelhaupt, Organometallics,
1996, 15, 174; H. Ramdane, H. Ranaivonjatovo, J. Escudie´, S. Mathieu
and N. Knouzi, Organometallics, 1996, 15, 3070.
8 S. J. Goede and F. Bickelhaupt, Chem. Ber., 1991, 124, 2677.
9 R. H. Fischer, M. Baumann and G. Ko¨brich, Tetrahedron Lett., 1974,
1207.
3
36.7, JHH 6.4, PNCH); dC (150 MHz, CDCl3) 28.8 (CMe2), 31.2 (CMe3),
33.2 (d, JPC 14.4, CMe3), 35.2 (CMe3), 35.9 (d, J 3.2, CMe2), 37.7 (CMe3),
41.8 (d, J 12.7, CH2), 119.2 (arom., CH), 121.4 (d, J 7.2, arom., CH), 131.6
(d, J 53.9, arom., CP), 148.8 (d, J 4.3, arom.), 152.2 (d, J 2.9, arom.), 153.1
(d, J 16.5, arom.), 168.3 (d, J 34.1, PNC); dP (81 MHz, CDCl3) 210.8 (dt,
2JPH 36.7, 3JPH 16.9); nmax(KBr)/cm21 1597; lmax(hexane)/nm (log e) 240
(3.86), 301 (3.84); m/z (70 eV) 288 (M+, 100), 273 (M+ 2 Me, 25), 57 (Bu+,
16); Found: 288.2011. Calc. for C19H29P: 288.2007. For (E)-8: colourless
crystals, mp 62–65 °C; dH (200 MHz) 1.33 (9 H, s, p-But), 1.50 (18 H, d,
5JPH 0.6, o-But), 2.14 (3 H, dd, 3JPH 25.3, 3JHH 8.4, Me), 7.39 (2 H, d, 4JPH
1.2, m-Ar), 7.44 (1 H, dq, 2JPH 25.4, 3JHH 8.4, PNCH); dC(50 MHz) 19.9 (d,
J 30.8, Me), 31.4 (p-CMe3), 32.5 (d, J 7.4, o-CMe3), 34.9 (p-CMe3), 38.2 (d,
J 0.7, o-CMe3), 121.5 (d, J 1.4, m-Ar), 139.9 (d, J 55.3, i-Ar), 149.2 (p-Ar),
153.5 (d, J 1.7, o-Ar), 175.1 (d, J 33.4, PNC); dP 250.3 (dq, 2JPH 25.4, 3JPH
10 M. T. Nguyen and T.-K. Ha, J. Mol. Struct: THEOCHEM, 1986, 139,
145.
11 M. Yoshifuji, K. Toyota, N. Inamoto, K. Hirotsu and T. Higuchi,
Tetrahedron Lett., 1985, 26, 6443; M. Yoshifuji, K. Toyota, I. Matsuda,
T. Niitsu, N. Inamoto, K. Hirotsu and T. Higuchi, Tetrahedron, 1988,
44, 1363; R. Appel, J. Menzel, F. Knoch and P. Volz, Z. Anorg. Allg.
Chem., 1986, 534, 100.
12 G. Ma¨rkl and W. Bauer, Angew. Chem., Int. Ed. Engl., 1989, 28,
1695.
Received in Cambridge, UK, 22nd May 1997; 7/03554C
1638
Chem. Commun., 1997