been utilised in asymmetric catalysis.10 Note these reaction
conditions are not optimised and the results represent only a
first glance at the catalytic potential of these ligands.
We thank the European Union (Erasmus Undergraduate
Exchange for I.M.-B.) and Newcastle University for
funding. We also thank the EPSRC for a Career Acceleration
Fellowship (L.J.H.), a Studentship (A.F.), an equipment grant
(W.C.), and its National Mass Spectrometry Service Centre,
Swansea, UK.
Notes and references
1 Reviews: (a) F. Mathey, Chem. Rev., 1990, 90, 997; (b) L. D. Quin,
in A Guide to Organophosphorus Chemistry, ed. L. D. Quin, John
Wiley Sons, New York, 2000, pp. 234-241; (c) F. Mathey and
M. Regitz, in Phosphorus–Carbon Heterocyclic Chemistry:
The Rise of a New Domain, ed. F. Mathey, Elsevier Science,
Amsterdam, 2001, pp. 17–55.
Fig. 3 View of the molecular structure of 4b. Hydrogen atoms have
been omitted for clarity. Selected average bond distances [A] and
angles [1]: Pt–Cl 2.338(3), Pt–P 2.204(3), P–C1 1.799(7), P–C2 1.811(7),
P–C3 1.802(7), C1–C2 1.550(10); Cl–Pt–Cl0 90.42(15), Cl–Pt–P
87.28(7), P–Pt–P 96.92(14), Pt–P–C3 115.3(2), C1–P–C3 110.6(3),
C2–P–C3 106.0(3), C1–P–C2 50.9(3); C3–C12–C13–C22 ꢀ94.7(8). A
prime indicates a symmetry-equivalent atom.
2 Phosphirane decomposes completely within 24
h at 25 1C:
R. I. Wagner, L. D. Freeman, H. Goldwhite and D. G. Rowsell,
J. Am. Chem. Soc., 1967, 89, 1102.
3 (a) Y. B. Kang, M. Pabel, A. C. Willis and S. B. Wild, J. Chem.
Soc., Chem. Commun., 1994, 475; (b) D. C. R. Hockless,
Y. B. Kang, M. A. McDonald, M. Pabel, A. C. Willis and
S. B. Wild, Organometallics, 1996, 15, 1301.
4 X. Li, K. D. Robinson and P. P. Gaspar, J. Org. Chem., 1996,
61, 7702.
5 M. Baudler and J. Germeshausen, Chem. Ber., 1985, 118, 4285.
6 T. Oshikawa and M. Yamashita, Synthesis, 1985, 290.
7 (a) J. Liedtke, S. Loss, G. Alcaraz, V. Gramlich and
4a of ꢀ81.8(10) and ꢀ88.5(9)1. These values compare well with
the related complex cis-dichlorobis[1-(9-anthracene)phosphirane]-
platinum(II)11b which exhibits slightly longer Pt–P bond
lengths of 2.235(4) and 2.256(4) A. This anthracenylphosphirane
derivative has a slightly higher strain within its heterocyclic
ring and is more pyramidalised at phosphorus (C–P–C bond
angles: 49.7(8)–49.8(8)1) than 4a or 4b.
Having established that the thermal and air-stability of our
phosphiranes does not infringe on their ability to coordinate to
a late transition metal, we sought to extend the research to
include a pilot study of the potential of these ligands for
H. Grutzmacher, Angew. Chem., 1999, 111, 1724 (Angew. Chem.,
¨
Int. Ed., 1999, 38, 1623); (b) J. Liedtke, S. Loss, C. Widauer and
H. Grutzmacher, Tetrahedron, 2000, 56, 143; (c) J. Liedtke,
¨
H. Ruegger, S. Loss and H. Grutzmacher, Angew. Chem., 2000,
¨
112, 3596 (Angew. Chem., Int. Ed., 2000, 39, 2478); (d) C. Laporte,
¨
G. Frison, H. Grutzmacher, A. C. Hillier, W. Sommer and
¨
asymmetric catalysis. As
a benchmark, the asymmetric
S. P. Nolan, Organometallics, 2003, 22, 2202.
8 (a) S. Maurer, C. Burkhart and G. Maas, Eur. J. Org. Chem.,
2010, 2504; (b) T. Jikyo and G. Maas, Chem. Commun., 2003,
2794.
9 R. M. Hiney, L. J. Higham, H. Muller-Bunz and D. G. Gilheany,
¨
Angew. Chem., 2006, 118, 7406 (Angew. Chem., Int. Ed., 2006,
45, 7248).
10 Phosphiranes with chirality on the heterocycle have been used in
asymmetric hydrogenations: A. Marinetti, F. Mathey and
L. Ricard, Organometallics, 1993, 12, 1207 and references therein.
11 (a) N. Mezailles, P. E. Fanwick and C. P. Kubiak, Organo-
´
metallics, 1997, 16, 1526; (b) F. Yang, P. E. Fanwick and
C. P. Kubiak, Organometallics, 1999, 18, 4222.
12 H. R. Hudson, in The Chemistry of Organophosphorus Compounds,
ed. F. R. Hartley, Wiley, New York, 1990, vol. 1, pp. 438–439 and
references therein.
13 B. Stewart, A. Harriman and L. J. Higham, submitted to
Organometallics, om-2011-00070a.
´
14 P. P. Gaspar, H. Qian, A. M. Beatty, D. Andre d’Avignon,
induction capabilities of (S)-2a and (R)-2b were investigated
in the catalytic hydrosilylation of styrene (Scheme 3).18 The
reaction is required to be both highly regio- and enantioselective;
oxidation of the initially formed trichlorosilane proceeds
with retention of configuration and chiral 1-phenylethanol is
produced (Scheme 3). Our catalysts were prepared in situ by
reacting the chiral phosphirane ligand with [PdCl(Z3-C3H5)]2.
The results obtained with the two ligands differ significantly.
The hydrogen substituent in the 20-position of the binaphthyl
backbone seems to promote the activity as well as the
enantioselectivity of the catalyst. A similar trend was found
for the related parent MOP ligands when used in this trans-
formation.19 The full conversion obtained with (S)-2a coupled
with attaining an enantiomeric excess of 80% indicates the
potential applications of this neglected class of ligand. To the
best of our knowledge this is the first time that phosphiranes
with the chirality located solely on the ligand backbone have
J. L.-F. Kao, J. C. Watt and N. P. Rath, Tetrahedron, 2000,
56, 105.
15 (a) D. C. R. Hockless, M. A. McDonald, M. Pabel and S. B. Wild,
J. Chem. Soc., Chem. Commun., 1995, 257; (b) D. C. R. Hockless,
M. A. McDonald, M. Pabel and S.B. Wild, J. Organomet. Chem.,
1997, 529, 189.
16 P. S. Pregosin, Annu. Rep. NMR Spectrosc., 1986, 17, 285.
17 C. M. Haar, S. P. Nolan, W. J. Marshal, K. G. Moloy, A. Prock
and W. P. Giering, Organometallics, 1999, 18, 474.
18 See e.g. J. W. Han and T. Hayashi, Tetrahedron: Asymmetry, 2010,
21, 2193 and references therein.
19 K. Kitayama, Y. Uozumi and T. Hayashi, J. Chem. Soc., Chem.
Commun., 1995, 1533; at 0 1C (S)-H-MOP gave full conversion in 12 h
with 93% ee, (R)-MOP required 24 h for full conversion (14% ee).
Scheme 3 The asymmetric hydrosilylation of styrene gives the chiral
trichlorosilane, subsequent oxidation of which gives 1-phenylethanol.
c
8276 Chem. Commun., 2011, 47, 8274–8276
This journal is The Royal Society of Chemistry 2011