Synthesis and X-ray crystal structures of bis(oxazolinyl)phenyl-derived chiral palladium(II) and platinum(II) and -(IV) complexes and their use in the catalytic asymmetric aldol-type condensation of isocyanides and aldehydes

Article abstract of DOI:10.1021/om020274q

The transmetalation of (Phebox)SnMe₃ (3; Phebox = 2,6-bis(oxazolinyl)phenyl) with PdCl₂(PhCN)₂ or K[PtCl₃(C₂H₄)](H₂O) gave (Phebox)M^IICl complexes (4, M = Pd; 5, M = Pt) in modest to good yields. The (Phebox)Pt^IvCl₃ complexes 8 were also synthesized by the reaction of 5 with CuCl₂(H₂O)₂ as an oxidant. These chloride complexes, 4, 5, and 8, were in turn converted to the cationic complexes by treatment with the corresponding silver salts (AgX: X = BF₄, OTf, OCOCF₃). X-ray structure studies revealed that the octahedral structure of (Phebox)Pt^IVCl₂ fragment G is isosteric with the (Phebox)Rh^IIICl₂ fragment D, and the (Phebox)M^II fragment H (M = Pd, Pt) is almost the same configuration with a square-planar structure. In these complexes, the cationic BF₄ aqua complexes (9, M = Pd^II; 10, M = Pt^II; 11, M = Pt^Iv) were found to act as chiral catalysts for the aldol-type condensation of isocyanides and aldehydes in the presence of i-Pr₂NEt. Excellent trans diastereoselectivities and modest to good enantioselectivities were obtained in the reaction of tosylmethyl isocyanide (TosMIC, 1) by the use of [(i-Pr-Phebox)Pt^II(H₂O)](BF₄) (i-Pr-10).

Full text of DOI:10.1021/om020274q

3408
Organometallics 2002, 21, 3408-3416
Syn th esis a n d X-r a y Cr ysta l Str u ctu r es of
Bis(oxa zolin yl)p h en yl-Der ived Ch ir a l P a lla d iu m (II) a n d
P la tin u m (II) a n d -(IV) Com p lexes a n d Th eir Use in th e
Ca ta lytic Asym m etr ic Ald ol-Typ e Con d en sa tion of
Isocya n id es a n d Ald eh yd es
Yukihiro Motoyama,* Hidekazu Kawakami, Kayoko Shimozono,
Katsuyuki Aoki, and Hisao Nishiyama
School of Materials Science, Toyohashi University of Technology,
Tempaku-cho, Toyohashi, Aichi 441-8580, J apan
Received April 5, 2002
The transmetalation of (Phebox)SnMe3 (3; Phebox ) 2,6-bis(oxazolinyl)phenyl) with PdCl2-
(PhCN)2 or K[PtCl3(C2H4)](H2O) gave (Phebox)MIICl complexes (4, M ) Pd; 5, M ) Pt) in
modest to good yields. The (Phebox)PtIVCl3 complexes 8 were also synthesized by the reaction
of 5 with CuCl2(H2O)2 as an oxidant. These chloride complexes, 4, 5, and 8, were in turn
converted to the cationic complexes by treatment with the corresponding silver salts (AgX:
X ) BF4, OTf, OCOCF3). X-ray structure studies revealed that the octahedral structure of
(Phebox)PtIVCl2 fragment G is isosteric with the (Phebox)RhIIICl2 fragment D, and the
(Phebox)MII fragment H (M ) Pd, Pt) is almost the same configuration with a square-planar
structure. In these complexes, the cationic BF4 aqua complexes (9, M ) PdII; 10, M ) PtII;
11, M ) PtIV) were found to act as chiral catalysts for the aldol-type condensation of
isocyanides and aldehydes in the presence of i-Pr2NEt. Excellent trans diastereoselectivities
and modest to good enantioselectivities were obtained in the reaction of tosylmethyl
isocyanide (TosMIC, 1) by the use of [(i-Pr-Phebox)PtII(H2O)](BF4) (i-Pr-10).
Sch em e 1
In tr od u ction
The aldol-type condensation of aldehydes and isocya-
nides containing an electron-withdrawing group (EWG)
at the R-carbon atom provides an important method for
access to synthetically useful 4,5-disubstituted 2-oxazo-
line compounds (Scheme 1).1 Since an asymmetric
version of the condensation with a chiral Au(I) catalyst
was disclosed in 1986 by Ito and Hayashi,2 several
groups have studied the catalytic systems based on the
use of chiral AuI,3 AgI,4 PdII,5 and PtII 5 complexes.
Nevertherless, there are only three types of chiral
(1) Reviews: (a) Ugi, I. Isonitrile Chemistry; Academic Press: New
York, 1971. (b) Hoppe, D. Angew. Chem., Int. Ed. Engl. 1974, 13, 789.
(c) Scho¨llkopf, U. Angew. Chem., Int. Ed. Engl. 1977, 16, 339. Also
see: (d) Scho¨llkopf, U.; Gerhart, F. Angew. Chem., Int. Ed. Engl. 1968,
7, 805. (e) Saegusa, T.; Ito, Y.; Kinoshita, H.; Tomita, S. J . Org. Chem.
1971, 36, 3316. (f) Hoppe, D.; Scho¨llkopf, U. J ustus Liebigs Ann. Chem.
1972, 763, 1. (g) Ito, Y.; Matsuura, T.; Saegusa, T. Tetrahedron Lett.
1985, 26, 5781. (h) Grigg, R.; Lansdell, M. I.; Thornton-Pett, M.
Tetrahedron 1999, 55, 2025.
(2) (a) Ito, Y.; Sawamura, M.; Hayashi, T. J . Am. Chem. Soc. 1986,
108, 6405. (b) Ito, Y.; Sawamura, M.; Shirakawa, E.; Hayashizaki, K.;
Hayashi, T. Tetrahedron Lett. 1988, 29, 235. (c) Sawamura, M.; Ito,
Y.; Hayashi, T. Tetrahedron Lett. 1989, 30, 2247. (d) Ito, Y.; Sawamura,
M.; Hamashima, H.; Emura, T.; Hayashi, T. Tetrahedron Lett. 1989,
30, 4681. (e) Hayashi, T.; Sawamura, M.; Ito, Y. Tetrahedron 1992,
48, 1999. (f) Soloshonok, V. A.; Kacharov, A. D.; Hayashi, T. Tetrahe-
dron 1996, 52, 245.
catalysts (A,2-4 B,5b C5c) with good to high enantio-
selectivities. These reported asymmetric catalysts have
deep chiral surroundings as a common structural unit,
because the enantioselective carbon-carbon bond for-
mation is accomplished at the R-carbon atom, very
distant from the metal center.
Previously, we designed an anionic “N-C-N pincer”
ligand,6 2,6-bis(oxazolinyl)phenyl (abbreviated as Phe-
box), and synthesized chiral rhodium(III) aqua com-
plexes, (Phebox)RhIIICl2(H2O), as new types of transition-
metal Lewis acids.7,8 During the course of our studies
(3) (a) Pastor, S. D.; Togni, A. J . Am. Chem. Soc. 1989, 111, 2333.
(b) Togni, A.; Ha¨usel, R. Synlett 1990, 633. (c) Togni, A.; Pastor, S. D.;
Rihs, G. J . Organomet. Chem. 1990, 381, C21. (d) Togni, A.; Pastor, S.
D. J . Org. Chem. 1990, 55, 1649. (e) Pastor, S. D.; Togni, A. Helv. Chim.
Acta 1991, 74, 905. (f) Zhou, X.-T.; Lin, Y.-R.; Dai, L.-X. Tetrahedron:
Asymmetry 1999, 10, 855.
(5) (a) Nesper, R.; Pregosin, P. S.; Pu¨ntener, K.; Wo¨rle, M. Helv.
Chim. Acta 1993, 76, 2239. (b) Gorla, F.; Togni, A.; Venanzi, L. M.;
Albinati, A.; Lianza, F. Organometallics 1994, 13, 1607. (c) Longmire,
J . M.; Zhang, X.; Shang, M. Organometallics 1998, 17, 4374.
(4) Sawamura, M.; Hamashima, H.; Ito, Y. J . Org. Chem. 1990, 55,
5935.
10.1021/om020274q CCC: $22.00 © 2002 American Chemical Society
Publication on Web 07/03/2002

Bis(oxazolinyl)phenyl-Derived Pd and Pt Complexes
Organometallics, Vol. 21, No. 16, 2002 3409
Sch em e 2
Sch em e 3
structure studies of Phebox-derived chiral PdII, PtII, and
PtIV complexes11 and asymmetric aldol-type condensa-
tions of isocyanides and aldehydes with these cationic
palladium and platinum complexes (Scheme 3).
Resu lts a n d Discu ssion
1. Syn th esis a n d X-r a y Cr ysta l Str u ctu r es of
P h ebox-P d II, -P tII, a n d -P tIV Com p lexes. The
complexes (Phebox)PdIICl (4) and (Phebox)PtIICl (5)
were synthesized by transmetalation of (Phebox)SnMe3
(3) with PdCl2(PhCN)2 or Zeise’s salt, K[PtCl3(C2H4)]-
(H2O), in dichloromethane at 0 °C in 40-96% yields
(Scheme 4).12 (Phebox)PtIVCl3 complexes 8 were pre-
pared from the corresponding PtII chloride complexes 5
by treatment of CuCl2(H2O)2 as an oxidant in dichloro-
ethane at 40 °C in almost quantitative yields.13 These
chloride complexes, 4, 5, and 8, were in turn converted
to the trifluoromethanesulfonate (OTf; 6), trifluoro-
acetate (OCOCF3; 7), and tetrafluoroborate (BF4; 9-11)
complexes with the corresponding silver salts in satis-
factory yields (62-99%), except in the cases of the Bn-
Phebox- and t-Bu-Phebox-derived PtIV complexes. Bn-
and t-Bu-11 are unstable in solution and decomposed
into metallic platinum and unidentified organic prod-
ucts.
The complexes (i-Pr-Phebox)PdIICl (i-Pr-4), (t-Bu-
Phebox)PtIVCl3 (t-Bu-8), [(i-Pr-Phebox)PdII(H2O)](BF4)
(i-Pr-9), and (s-Bu-Phebox)RhIIICl2(H2O) were charac-
terized by single-crystal X-ray structure studies (Figure
1). Including the (i-Pr-Phebox)PtCl complex (i-Pr-5) and
[(i-Pr-Phebox)Pt(H2O)](BF4) complex (i-Pr-10), which
have been reported previously,11 the structural features
of all PdII, PtII, and PtIV complexes are almost identical.
A summary of selected data is given in Table 1. The
coordination geometries around the metal centers
are distorted-square-planar or octahedral structures:
on the Phebox-RhIII systems, containing deep chiral
pockets, we have found that isocyanide compounds can
bind to the rhodium atom, forming stable isocyanide
complexes (Scheme 2, E), and these isocyanide compo-
nents on the (Phebox)RhIIICl2 fragment D readily
reacted with aldehydes in the presence of t-BuOK as a
base to afford the corresponding aldol adducts as chiral
Fischer carbene complexes F with high trans diaste-
reoselectivities and modest to good diastereofacial se-
lectivities, even in a stoichiometric manner.9 These
results clearly show that the chiral environment con-
structed by an octahedral structure of the (Phebox)RhIII
-
Cl2 fragment D is effective for the aldol-type condensa-
tion of isocyanides and aldehydes. We also succeeded
in the isolation of 2-oxazoline derivatives from these
carbene complexes F by treatment with AgBF4. This
phenomenon encouraged us to use Phebox-derived cat-
ionic complexes,10 such as Phebox-PtIV (G) and Phe-
box-PtII and -PdII complexes (H), for the catalytic
asymmetric version of the present reaction because the
(Phebox)PtIVCl2 fragment G may be isosteric with the
(Phebox)RhIIICl2 fragment D, and the (Phebox)MII frag-
ment H (M ) Pd, Pt) is thought to be a similar type of
chiral assembly with a square-planar structure. Now
we wish to report herein the synthesis and X-ray
(6) Reviews: (a) Bianchini, C.; Meli, A.; Peruzzini, M.; Vizza, F.;
Zanobini, F. Coord. Chem. Rev. 1992, 120, 193. (b) Cotton, F. A.; Hong,
B. Prog. Inorg. Chem. 1992, 40, 179. (c) Mayer, H. A.; Kaska, W. C.
Chem. Rev. 1994, 94, 1239. (d) Rietveld, M. H. P.; Grove, D. M.; van
Koten, G. New J . Chem. 1997, 21, 751. (e) Rybtchinski, B.; Milstein,
D. Angew. Chem., Int. Ed. 1999, 38, 870. (f) J ensen, C. M. Chem.
Commun. 1999, 2443. (g) Albrecht, M.; van Koten, G. Angew. Chem.,
Int. Ed. 2001, 40, 3750.
(7) (a) Motoyama, Y.; Makihara, N.; Mikami, Y.; Aoki, K.; Nishi-
yama, H. Chem. Lett. 1997, 951. (b) Motoyama, Y.; Narusawa, H.;
Nishiyama, H. Chem. Commun. 1999, 131. (c) Motoyama, Y.; Koga,
Y.; Nishiyama, H. Tetrahedron 2001, 53, 853. (d) Motoyama, Y.; Okano,
H.; Narusawa, H.; Makihara, N.; Aoki, K.; Nishiyama, H. Organome-
tallics 2001, 20, 1580.
(8) Phebox-coordinated palladium(II) complexes were reported;
see: (a) Denmark, S. E.; Stavenger, R. A.; Faucher, A.-M.; Edwards,
J . P. J . Org. Chem. 1997, 62, 3375. (b) Stark, M. A.; Richards, C. J .
Tetrahedron Lett. 1997, 38, 5881. (c) Stark, M. A.; J ones, G.; Richards,
C. J . Organometallics 2000, 19, 1282. Recently, a similar type of ligand,
2,6-bis(oxazolylmethyl)-4,6-dimethylbenzene (BenboxMe2), and its co-
ordinated rhodium(II) and rhodium(III) complexes were reported;
see: (d) Gerisch, M.; Krumper, J . R.; Bergman, R. G.; Tilley, T. D. J .
Am. Chem. Soc. 2001, 123, 5818.
(10) van Koten reported that the cationic PdII complexes bearing
N-C-N pincer ligands acted as efficient catalysts for the reaction of
methyl isocyanoacetate and aldehydes; see: (a) Schlenk, C.; Kleij, A.
W.; Frey, H.; van Koten, G. Angew. Chem., Int. Ed. 2000, 39, 3445. (b)
Kleij, A. W.; Klein Gebbink, R. J . M.; van den Nieuwenhuijzen, P. A.
J .; Kooijman, H.; Lutz, M.; Spek, A. L.; van Koten, G. Organometallics
2001, 20, 634. (c) Meijer, M. D.; Ronde, N.; Vogt, D.; van Klink, G. P.
M.; van Koten, G. Organometallics 2001, 20, 3993. (d) Albrecht, M.;
Kocks, B. M.; Spek, A. L.; van Koten, G. J . Organomet. Chem. 2001,
624, 271. (e) Rodriguez, G.; Lutz, M.; Spek, A. L.; van Koten, G. Chem.
Eur. J . 2002, 8, 46.
(11) We have previously reported the synthesis of i-Pr-Phebox-
derived PdII, PtII, and PtIV complexes (i-Pr-4, i-Pr-5, i-Pr-6, and i-Pr-
8); see: Motoyama, Y.; Mikami, Y.; Kawakami, H.; Aoki, K.; Nishiya-
ma, H. Organometallics 1999, 18, 3584. See also ref 7a.
(12) The N-C-N pincer-ligand-coordinated PdII complexes prepared
by the transmetalation of stannane or silane derivatives were reported
by van Koten; see: Steenwinkel, P.; J astrzebski, J . T. B. H.; Deelman,
B.-D.; Grove, D. M.; Kooijman, H.; Veldman, N.; Smeets, W. J . J .; Spek,
A. L.; van Koten, G. Organometallics 1997, 16, 5486.
(13) The PtIV complexes [PtX3(C6H3(CH2NMe2)2-o,o′] (X ) Cl, Br)
were formed in the reaction of the square-planar PtII complex [PtX-
(C6H3(CH2NMe2)2-o,o′] (X ) Cl, Br) with CuIIX2 (X ) Cl, Br); see:
Terheijden, J .; van Koten, G.; de Booys, J . L.; Ubbels, H. J . C.; Stam,
C. H. Organometallics 1983, 2, 1882.
(9) Motoyama, Y.; Shimozono, K.; Aoki, K.; Nishiyama, H. Organo-
metallics 2002, 21, 1684.

3410 Organometallics, Vol. 21, No. 16, 2002
Motoyama et al.
Sch em e 4a
a
Legend: (i) PdCl2(PhCN)2/CH2Cl2/0 °C; (ii) K[PtCl3(C2H4)](H2O)/CH2Cl2/0 °C; (iii) CuCl2(H2O)2/dichloroethane/40 °C; (iv) AgBF4/
acetone-H2O/room temperature; (v) AgX (X ) OTf, OCOCF3)/CH2Cl2/room temperature.
F igu r e 1. Molecular structures of i-Pr-4‚H2O, i-Pr-5, t-Bu-8, i-Pr-9, i-Pr-10, and (s-Bu-Phebox)RhIIICl2(H2O).
N-M-N (M ) Pd, Pt, Rh) angles are 158.6-159.6°. The
M-N bond and the σ-bonded M-C1 distances are
2.032-2.071 and 1.90-1.96 Å, respectively. According
to our expectation, these results show that the (Phebox)-
% of the (S,S)-Phebox-derived PtIV, PtII, and PdII com-
plexes as chiral catalysts in the presence of 10 mol % of
base at 0 °C (Table 2). First of all, the i-Pr-Phebox-
derived cationic aqua complexes 9-11 gave the desired
2-oxazoline product 12a in good to high yields, but only
trace amounts of 12a were obtained with the neutral
species such as triflate (OTf) and trifluoroacetate
(OCOCF3) complexes (i-Pr-6 and i-Pr-7) (entries 1-5).
These results indicated that the OTf and OCOCF3
ligands might coordinate strongly to the metal center;
therefore, ligand exchange reaction from these anionic
ligands to the isocyanide 1 could hardly occur. Although
diastereoselectivities of the reactions with complexes
PtIVCl2 fragment G is isosteric with the (Phebox)RhIII
-
Cl2 fragment D, and both the (Phebox)PdII and (Phebox)-
PtII fragments have almost the same configuration with
square-planar structures.
2. Asym m etr ic Ald ol-Typ e Con d en sa tion of Iso-
cya n id es a n d Ald eh yd es. (i) Rea ction of TosMIC
a n d Ben za ld eh yd e. The optimization of the aldol-type
condensation conditions employed tosylmethyl isocya-
nide (TosMIC; 1) and benzaldehyde by the use of 2 mol

Bis(oxazolinyl)phenyl-Derived Pd and Pt Complexes
Organometallics, Vol. 21, No. 16, 2002 3411
Ta ble 1. Selected Bon d Len gth s (Å) a n d An gles (d eg) for (i-P r -P h ebox)P d Cl‚H2O (i-P r -4‚H2O),
(i-P r -P h ebox)P tCl (i-P r -5), (t-Bu -P h ebox)P tCl3 (t-Bu -8), (s-Bu -P h ebox)Rh Cl2(H2O),
[(i-P r -P h ebox)P d (H2O)](BF 4) (i-P r -9), a n d [(i-P r -P h ebox)P t(H2O)](BF 4) (i-P r -10)
i-Pr-4‚H2O
i-Pr-5a
t-Bu-8
(s-Bu-Phebox)RhCl2(H2O)b
i-Pr-9
i-Pr-10a
M-C1
1.92(1)
1.928(10)
2.032(10)
2.035(10)
2.379(3)
1.96(1)
1.90(1)
1.95(1)
2.069(10)
2.069(10)
1.96(3)
2.04(2)
2.04(2)
M-N1
2.053(9)
2.053(9)
2.391(3)
2.065(8)
2.065(8)
2.417(3)
2.312(3)
2.314(3)
2.033(9)
2.071(1)
2.326(3)
2.326(4)
M-N2(N1*)
M-Cl1
M-Cl2
M-Cl3
M-O
2.273(8)
159.1(4)
2.15(1)
158.8(5)
2.15(2)
159(1)
N1-M-N2(N1*)
159.6(5)
158.6(5)
159.3(3)
a
b
Reference 11 (i-Pr-5, CCDC-179828; i-Pr-10, CCDC-179829). One of the two independent crystal structures.
Ta ble 2. Asym m etr ic Ald ol-Typ e Con d en sa tion of
TosMIC (1) a n d Ben za ld eh yd e w ith Va r iou s
P h ebox Com p lexesa
Ta ble 3. Asym m etr ic Ald ol-Typ e Con d en sa tion of
TosMIC (1) a n d Va r iou s Ald eh yd es w ith i-P r -10a
entry complex
amine
% yield % transb % eec
1
2
3
4
5
6d
7
8
9
i-Pr-11
i-Pr-10
i-Pr-9
i-Pr-6
i-Pr-7
i-Pr-10
Ph-10
Bn-10
s-Bu-10 i-Pr2NEt
t-Bu-10 i-Pr2NEt
i-Pr-10
i-Pr-10
i-Pr-10
i-Pr-10
i-Pr2NEt
99
99
58
6
>99
>99
>99
>99
>99
>99
>99
>99
>99
25
68
57
i-Pr2NEt
i-Pr2NEt
i-Pr2NEt
i-Pr2NEt
i-Pr2NEt
i-Pr2NEt
i-Pr2NEt
5
99
92
85
87
<2
99
99
95
99
53
<3
23
32
10
11
12
13
14
n-Bu3N
Et3N
pyrrolidine-N-Me
DABCO
>99
>99
>99
>99
57
46
46
41
a
All reactions were carried out using 0.01 mmol of Phebox
complex, 0.05 mmol of amine, 0.5 mmol of TosMIC (1), and 0.6
mmol of benzaldehyde in 2 mL of THF at 0 °C for 24 h.
b
1
Determined by H NMR analysis. c Determined by HPLC analy-
d
sis using Daicel CHIRALCEL OD-H. At -20 °C for 24 h.
9-11 were perfectly trans, enantiomeric excesses of the
obtained 12a with square-planar PtII and PdII complexes
(68% ee for i-Pr-10 and 57% ee for i-Pr-9) were higher
than that with i-Pr-11 of octahedral geometry (25% ee),
which is isosteric with the (Phebox)RhCl2 fragments D.
The enantioselectivity of the reaction with i-Pr-10 did
not improve at -20 °C (entry 6). The substituent on the
oxazoline rings had a great effect on the chemical yields
and percent ee’s (entry 2 vs entries 6-9). The reaction
with the t-Bu-Phebox-derived complex (t-Bu-10) afforded
only trace amounts of 12a . The enantioselectivities
using Ph-, Bn-, and s-Bu-10 were remarkably decreased.
We also examined the effect of amine on enantioselec-
tivity and found that the sterically hindered Hu¨nig base
showed higher selectivity (entries 2 and 10-13).
(ii) Rea ction of TosMIC a n d Oth er Ald eh yd es.
Table 3 summarizes the results obtained for the aldol-
type condensation of TosMIC (1) and a variety of
aldehydes with 2 mol % of the complex i-Pr-10 in THF
in the presence of 10 mol % of i-Pr2NEt at 0 °C for 24 h.
All reactions resulted in good to high yields with
thorough trans diastereoselectivities. Despite the elec-
tronic factors, the enantioselectivities of the reaction
with para-substituted benzaldehydes were significantly
decreased (entries 2 and 3). In the reaction with ortho-
substituted benzaldehydes, enantiomeric excesses of the
corresponding 2-oxazolines 12d ,e were almost the same
degrees as that of the benzaldehyde-derived product 12a
(entries 4 and 5). Using bulky pivalaldehyde as an
aliphatic aldehyde, the enantioselectivity in the reaction
a
All reactions were carried out using 0.01 mmol of i-Pr-10, 0.05
mmol of i-Pr2NEt, 0.5 mmol of TosMIC (1), and 0.6 mmol of
aldehyde in 2 mL of THF at 0 °C for 24 h. Determined by 1H
b
NMR analysis. c Determined by HPLC analysis using Daicel
d
CHIRALCEL OD-H or CHIRALPAK AD. Assignment by com-
parison of the sign of optical rotation with the reported value; see
the Experimental Section.
reached 75% ee (entry 7). In all of the cases, the absolute
stereochemistry of the obtained 2-oxazolines 12 is 4S,5S.
(iii) R ea ct ion of Met h yl Isocya n oa cet a t e a n d
Ben za ld eh yd e. We also examined the reaction of
methyl isocyanoacetate 2 and benzaldehyde catalyzed
by Phebox-PdII and -PtII aqua complexes 9 and 10
(Table 4). Both of the i-Pr-Phebox-derived PdII and PtII
complexes i-Pr-9 and i-Pr-10 showed remarkably low
enantioselectivities (∼14% ee; entries 1 and 2). The
reaction with [(Bn-Phebox)PtII(H2O)](BF4) (Bn-10) af-
forded the oxazoline 13 in almost quantitative yield with
a trans/cis ratio of 87:13 (entry 3). The trans isomer
proved to be 36% ee with an 4R,5S configuration,2a
which is the same π-face selectivity at the carbonyl
group as in the case of TosMIC (1). The enantiomeric
excess of the product 13 was slightly increased (41% ee)
when the reaction temperature was lowered to 0 °C
(entry 4). In comparison to TosMIC (1), however, both
the diastereo- and enantioselectivity are at low levels
in the reaction of 2.

3412 Organometallics, Vol. 21, No. 16, 2002
Motoyama et al.
Ta ble 4. Asym m etr ic Ald ol-Typ e Con d en sa tion of
Meth yl Isocya n oa ceta te (2) a n d Ben za ld eh yd e
w ith P h ebox-P d II a n d -P tII Aqu a Com p lexes 9
a n d 10a
entry complex
conditions
% yield trans/cisb (% ee)c
1
2
3
4
i-Pr-9
i-Pr-10
Bn-10
Bn-10
room temp, 4 h
room temp, 5 h
room temp, 5 h
0 °C, 6 h
>99
99
99
80 (<3):20
86 (14):14
87 (36):13
87 (41):13
91
F igu r e 2. Antiperiplanar transition states J and K.
a
All reactions were carried out using 0.01 mmol of Phebox
complex, 0.05 mmol of i-Pr2NEt, 0.6 mmol of methyl isocyano-
acetate (2), and 0.5 mmol of benzaldehyde in 2 mL of THF.
b Determined by 1H NMR analysis. c Determined by capillary GLC
analysis using Astec Chiraldex G-TA (30M) and by HPLC analysis
using Daicel CHIRALCEL OD-H.
Sch em e 5
F igu r e 3. Structures of the enolate complexes L (left) and
M (right).
selectively with aldehydes. This trans-selective reaction
of the enolate I with aldehydes can be attributed to the
gauche interaction between the R groups of aldehydes
and the isocyano moiety bound to the bulky (i-Pr-
Phebox)PtII fragment H′ in antiperiplanar transition
states (Figure 2, J vs K).
3. Mech a n istic Stu d ies. (i) NMR Stu d ies of th e
Rea ction In ter m ed ia te. To obtain information about
the reaction intermediate, we first checked the com-
plexation between [(i-Pr-Phebox)PtII(H2O)](BF4) (i-Pr-
1
10) and TosMIC (1) (Scheme 5).14 The H NMR spec-
The possible structures of the TosMIC-derived PtII-
enolate complexes are shown in Figure 3. The observed
4S,5S stereochemistry of the obtained 2-oxazolines 13
using (S,S)-[(i-Pr-Phebox)PtII(H2O)](BF4) complex (i-Pr-
10) can be unambiguously explained by the intermedi-
ate L, whose structure is similar to that of the Phebox-
RhIII system with the octahedral geometry.9 The enolate
plane bound to the PtII atom is perpendicular to the
Phebox plane, and the re face of the enolate is masked
by one i-Pr substituent on the oxazoline rings. The
aldehydes attacked the exposed si face of the bound
enolate; therefore, the 4S,5S product was obtained. If
the bound enolate plane was placed almost parallel to
the Phebox plane (M), the opposite 4R,5R product would
be obtained as the major isomer.
trum of the 1:1 mixture of i-Pr-10 (0.017 mmol) and
TosMIC (0.017 mmol) in THF-d8 (0.7 mL) showed
formation of the isocyanide complex 14 (>98%). Because
of its potentially diastereotopic environments, the sig-
nals for the R-methylene protons of bound TosMIC to
the chiral (Phebox)PtII fragment H′ can be observed as
two nonequivalent AB patterns.9,14 However, the 1H
NMR spectrum for 14 shows the equivalent CH2SO2-
Tol signal at lower field with 197Pt-1H coupling (δ 5.72
ppm, J Pt-H ) 10.3 Hz) than the uncomplexed (free) one
(δ 5.01 ppm). These results suggested that the rotation
along the CR-Nisocyanide bond is faster than the NMR
time scale for the TosMIC complex 14. Addition of
aldehydes to this mixture did not cause a detectable
1
change of the H NMR spectrum, indicating that alde-
The reason the square-planar PtII complex shows
much higher enantioselectivity than does the octahedral
PtIV complex is unclear. Considering the effect of
Hu¨nig’s bases on the enantioselectivities, we assumed
that the location of an ammonium salt forming depro-
tonation from the isocyanide is playing a key role in the
stereoselection by interaction with the formed enolate.
A similar hypothesis is described in the ferrocenylphos-
phine-derived Au(I) system by Hayashi and Ito; the
amino group is located close to the isocyanide bound to
the metal, and therefore, the arrangement of the enolate
is controlled (Scheme 1, A).2e,14
hyde is hardly coordinated to the platinum atom. While
i-Pr2NEt was added to the catalyst-TosMIC solution,
the signals due to the formed isocyanide complex 14
gradually faded and the resulting spectrum showed a
complicated mixture. It is known that the R-isocyano
carbanion species are thermolabile and easily decom-
posed between -60 and 0 °C.1 Therefore, we assumed
that an enolate complex such as I is formed immediately
via deprotonation of TosMIC’s R-proton bound to the
(Phebox)Pt fragment H′ by Hu¨nig’s base.
(ii) Tr a n sition Sta te Assem bly. Since the relative
stereochemistry of the obtained 2-oxazolines 13 is trans,
the chiral enolates I bound to the PtII atom react trans
Con clu sion
(14) Similar NMR studies of chiral isocyanide complexes were
reported; see: Sawamura, M.; Ito, Y.; Hayashi, T. Tetrahedron Lett.
1990, 31, 272. See also refs 3d and 5a.
On the basis of our previous work using the Phebox-
RhIII system, we have sought to adopt the Phebox-

Bis(oxazolinyl)phenyl-Derived Pd and Pt Complexes
Organometallics, Vol. 21, No. 16, 2002 3413
132.7, 163.0. Anal. Found for C20H27N2O2Br: C, 59.02; H, 6.61;
N, 6.93. Calcd: C, 58.97; H, 6.68; N, 6.88.
derived cationic palladium(II) and platinum(II) and -(IV)
complexes for the catalytic asymmetric aldol-type con-
densation of isocyanides and aldehydes. We have de-
scribed the synthesis of a series of Phebox-PdII, -PtII,
and -PtIV complexes, and X-ray structure studies
including the (Phebox)RhIIICl2(H2O) complex revealed
that the octahedral structure of the (Phebox)PtIVCl2
fragment is isosteric with the (Phebox)RhIIICl2 frag-
ment, and the (Phebox)MII fragment (M ) Pd, Pt) is
almost the same configuration with a square-planar
structure. We have found that the cationic aqua com-
plexes, especially the [(i-Pr-Phebox)PtII(H2O)](BF4) com-
plex with a square-planar structure, acted as efficient
asymmetric catalysts for the aldol-type condensation of
isocyanides and aldehydes. We also elucidated that the
obtained 4S,5S stereochemistry of the 2-oxazolines can
be attributed to the perpendicular conformation of both
the enolate and the (S,S)-Phebox planes of the TosMIC-
derived enolate intermediate.
(s-Bu -P h ebox)Sn Me3 (s-Bu -3). This compound was pre-
pared from (s-Bu-Phebox)Br and Me3SnCl according to our
method.7d Colorless oil. IR (neat): ν 2963, 1651, 1459, 1351,
1248, 1131, 979, 770 cm-1. 1H NMR (400 MHz, CDCl3): δ 0.20
(s, satellite J Sn-H ) 55.5, 53.0 Hz, 9H), 0.87 (d, J ) 6.7 Hz,
6H), 0.95 (t, J ) 7.3 Hz, 6H), 1.25 (m, 2H), 1.61-1.75 (m, 4H),
4.07 (dd, J ) 9.1, 7.7 Hz, 2H), 4.14 (ddd, J ) 9.2, 9.1, 6.6 Hz,
2H), 4.43 (dd, J ) 9.2, 7.7 Hz, 2H), 7.35 (t, J ) 7.7 Hz, satellite
J Sn-H ) 5.7 Hz, 1H), 7.89 (d, J ) 7.7 Hz, satellite J Sn-H ) 12.0
Hz, 2H). 13C NMR (100 MHz, CDCl3): δ -3.6 (satellite J Sn-C
) 386.5, 368.8 Hz), 11.4, 14.9, 26.2, 39.5, 70.8, 71.9, 127.8
(satellite J Sn-C ) 8.2 Hz), 130.8 (satellite J Sn-C ) 31.5 Hz),
136.2 (satellite J Sn-C ) 19.1 Hz), 147.3 (satellite J Sn-C ) 465.1,
443.4 Hz), 165.3 (satellite J Sn-C ) 14.5 Hz). Anal. Found for
C
23H36N2O2Sn: C, 56.26; H, 7.37; N, 5.66. Calcd: C, 56.23; H,
7.39; N, 5.70.
(s-Bu -P h ebox)Rh Cl2(H2O). This compound was prepared
from (s-Bu-Phebox)SnMe3 (s-Bu-3) and [RhCl(c-octene)2]2 ac-
cording to our method.7e Single crystals for the X-ray diffrac-
tion study were obtained from hexane-ether at room temper-
ature. Pale yellow solid. Mp: 134 °C dec. IR (KBr): ν 3763,
Exp er im en ta l Section
1
2962, 2925, 1620, 1487, 1397, 962 cm-1. H NMR (400 MHz,
CDCl3): δ 0.89 (d, J ) 6.8 Hz, 6H), 0.98 (t, J ) 7.3 Hz, 6H),
1.22 (m, 2H), 1.31 (m, 2H), 2.41 (m, 2H), 2.89 (bs, 2H), 4.37
(ddd, J ) 10.1, 6.8, 2.9 Hz, 2H), 4.67 (dd, J ) 8.8, 6.8 Hz, 2H),
4.74 (dd, J ) 10.1, 8.8 Hz, 2H), 7.28 (t, J ) 7.7 Hz, 1H), 7.57
(d, J ) 7.7 Hz, 2H). 13C NMR (100 MHz, CDCl3): δ 12.0, 12.5,
27.0, 36.0, 66.1, 71.2, 123.4, 128.1, 131.5, 170.7 (J Rh-C ) 3.8
Hz), 179.4 (J Rh-C ) 22.8 Hz). Anal. Found for C20H29N2O3Cl2-
Rh: C, 46.33; H, 5.54; N, 5.32. Calcd: C, 46.26; H, 5.63; N,
5.39.
Gen er a l Meth od s. Anhydrous dichloromethane and tet-
rahydrofuran were purchased from Kanto Chemical Co. (p-
Tolylsulfonyl)methyl isocyanide (TosMIC) was purchased from
Tokyo Chemical Industry Co., Ltd. Methyl isocyanoacetate,
silver triflate, silver trifluoroacetate, and silver tetrafluorobo-
rate were purchased from Aldrich Chemical Co. Dichloroet-
hane was freshly distilled from CaH2. 1H and 13C NMR spectra
were measured on a Varian Inova-400 (400 MHz) spectrom-
eter. 1H NMR chemical shifts were described in parts per
million downfield from tetramethylsilane as an internal
standard (δ 0) in CDCl3, unless otherwise noted. 13C NMR
chemical shifts were expressed in parts per million in CDCl3
as an internal standard (δ 77.1), unless otherwise noted. IR
spectra were measured on a J ASCO FT/IR-230 spectrometer.
Melting points were measured on a Yanaco MP-J 3 apparatus.
Elemental analyses were measured on a Yanaco CHN CORDER
MT-6 instrument. High-performance liquid chromatography
(HPLC) analyses were performed with a J ASCO PU-980 HPLC
pump, UV-975 and 980 UV/VIS detector, and CO-966 column
thermostat (at 25 °C) using Daicel CHIRALCEL OD-H and
CHIRALPAK AD columns. Optical rotations were measured
on a J ASCO DIP-140 polarimeter. Column chromatography
was performed with silica gel (Merck, Art. No. 7734) and with
Al2O3 (Merck, Art. No. 1097). Analytical thin-layer chroma-
tography (TLC) was performed on glass plates and aluminum
sheets precoated with silica gel (Merck, Kieselgel 60 F254, layer
thicknesses 0.25 and 0.2 mm, respectively). Visualization was
accomplished by UV light (254 nm), anisaldehyde, and phos-
phomolybdic acid. All reactions were carried out under a
nitrogen or argon atmosphere. (Phebox)SnMe3 (3) was pre-
pared by our method.7d
(i-P r -P h ebox)P d Cl (i-P r -4). White solids. Mp: 244-246
°C dec. IR (KBr): ν 2954, 1614, 1483, 1398, 1149, 957 cm-1
.
1H NMR (400 MHz, CDCl3): δ 0.83 (d, J ) 6.8 Hz, 6H), 0.94
(d, J ) 7.2 Hz, 6H), 2.83 (dqq, J ) 3.6, 7.2, 6.8 Hz, 2H), 4.36
(ddd, J ) 8.0, 7.6, 3.6 Hz, 2H), 4.64 (d, J ) 7.6 Hz, 2H), 4.65
(d, J ) 8.0 Hz, 2H), 7.16 (t, J ) 8.0 Hz, 1H), 7.31 (d, J ) 8.0
Hz, 2H). 13C NMR (100 MHz, CDCl3): δ 14.3, 19.0, 29.1, 67.0,
71.2, 124.0, 127.0, 129.6, 168.0, 173.9. Anal. Found for
C
18H23N2O2ClPd: C, 48.90; H, 5.18; N, 6.37. Calcd: C, 48.99;
H, 5.25; N, 6.35. Single crystals for the X-ray diffraction study
were obtained as (i-Pr-Phebox)PdCl•(H2O) from dichloro-
methane-hexane at room temperature. Anal. Found for
C
18H23N2O2ClPd‚H2O: C, 46.95; H, 5.49; N, 6.07. Calcd: C,
47.08; H, 5.49; N, 6.10.
(i-P r -P h ebox)P tCl (i-P r -5). Yellow solids. Single crystals
for the X-ray diffraction study were obtained from ethyl acetate
at room temperature. Mp: 261-263 °C dec. IR (KBr): ν 2956,
1
1603, 1484, 1401, 1330, 1148, 959 cm-1. H NMR (400 MHz,
CDCl3): δ 0.79 (d, J ) 6.8 Hz, 6H), 0.96 (d, J ) 7.2 Hz, 6H),
2.90 (dqq, J ) 7.2, 6.8, 3.6 Hz, 2H), 4.42 (dt, J ) 7.8, 3.6 Hz,
2H), 4.76 (d, J ) 7.8 Hz, 4H), 7.18 (t, J ) 7.6 Hz, 1H), 7.38 (d,
J ) 7.6 Hz, satellite J Pt-H ) 8.0 Hz, 2H). 13C NMR (100 MHz,
CDCl3): δ 13.9, 18.8, 28.9, 67.0 (satellite, J Pt-C ) 34.0 Hz),
73.1 (satellite, J Pt-C ) 22.0 Hz), 126.0 (satellite, J Pt-C ) 38.5
Hz), 126.8, 131.0 (satellite, J Pt-C ) 23.2 Hz), 158.7 (sate-
llite, J Pt-C ) 734.9 Hz), 176.8. Anal. Found for C18H23N2O2-
ClPt: C, 40.73; H, 4.31; N, 5.37. Calcd: C, 40.80; H, 4.37; N,
5.29.
PdCl(PhCN)215 and K[PtCl3(C2H4)](H2O)16 were prepared by
the literature methods.
(s-Bu -P h ebox)Br . This compound was prepared from
(2S,3S)-2-amino-3-methylpentan-1-ol and 2-bromo-m-xylene
according to our method.7d Colorless oil. [R]D20 ) -76.4° (c 1.06,
CHCl3). IR (neat): ν 2962, 2876, 1664, 1584, 1460, 1363, 1131,
1
971, 730 cm-1. H NMR (400 MHz, CDCl3): δ 0.93 (d, J ) 6.8
(P h -P h ebox)P tCl (P h -5). Yellow solids. Mp: >295 °C. IR
(KBr): ν 2950, 1605, 1580, 1490, 1400, 1330, 1150, 960 cm-1
.
Hz, 6H), 0.96 (t, J ) 7.4 Hz, 6H), 1.27 (m, 2H), 1.61 (m, 2H),
1.77 (m, 2H), 4.18 (dd, J ) 8.0, 7.9 Hz, 2H), 4.28 (ddd, J )
9.6, 8.0, 5.8 Hz, 2H), 4.43 (dd, J ) 9.6, 7.9 Hz, 2H), 7.37 (t, J
) 7.6 Hz, 1H), 7.64 (d, J ) 7.6 Hz, 2H). 13C NMR (100 MHz,
CDCl3): δ 11.6, 14.5, 26.1, 39.0, 70.1, 71.6, 121.4, 127.0, 132.4,
1H NMR (400 MHz, CDCl3): δ 4.79 (dd, J ) 8.8, 5.6 Hz, 2H),
5.11 (dd, J ) 10.0, 8.8 Hz, 2H), 5.39 (dd, J ) 10.0, 5.6 Hz,
2H), 7.18 (t, J ) 7.6 Hz, 1H), 7.24-7.34 (m, 10H), 7.43 (d, J )
7.6 Hz, satellite, J Pt-H ) 7.5 Hz, 2H). 13C NMR (100 MHz,
CDCl3): δ 65.6 (satellite, J Pt-C ) 34.9 Hz), 79.7 (satellite, J Pt-C
) 25.8 Hz), 122.2, 127.3, 127.6, 127.7, 128.4, 128.8, 139.7,
162.5, 179.8. Anal. Found for C24H19N2O2ClPt: C, 47.98; H,
3.09; N, 4.58. Calcd: C, 48.21; H, 3.20; N, 4.68.
(15) Doyle, J . R.; Slade, P. E.; J onassen, H. B. Inorg. Synth. 1960,
6, 218.
(16) Chatt, J .; Searle, M. L. Inorg. Synth. 1957, 5, 210.

3414 Organometallics, Vol. 21, No. 16, 2002
Motoyama et al.
(Bn -P h ebox)P tCl (Bn -5). Yellow solids. Mp: 292 °C dec.
176.7 (satellite, J Pt-C ) 105.2 Hz). Anal. Found for C18H23N2O2-
Cl3Pt: C, 35.97; H, 3.92; N, 4.65. Calcd: C, 35.98; H, 3.86; N,
4.66.
1
IR (KBr): ν 2921, 1654, 1561, 1491, 1405, 973, 671 cm-1. H
NMR (400 MHz, CDCl3): δ 3.04 (dd, J ) 13.6, 8.0 Hz, 2H),
3.73 (dd, J ) 13.6, 3.2 Hz, 2H), 4.68-4.85 (m, 6H), 7.13 (t, J
) 7.2 Hz, 1H), 7.18-7.39 (m, 12H). 13C NMR (100 MHz,
CDCl3): δ 39.9, 63.4 (satellite, J Pt-C ) 34.5 Hz), 75.7 (satellite,
J Pt-C ) 27.4 Hz), 122.3, 126.9, 127.4 (satellite, J Pt-C ) 40.2
Hz), 127.8 (satellite, J Pt-C ) 37.8 Hz), 128.7, 129.8, 136.3, 161.5
(satellite, J Pt-C ) 861.1 Hz), 179.5 (satellite, J Pt-C ) 192.4 Hz).
Anal. Found for C26H23N2O2ClPt: C, 49.96; H, 3.85; N, 4.48.
Calcd: C, 49.88; H, 3.70; N, 4.47.
(Bn -P h ebox)P tCl3 (Bn -8). Yellow solids. Mp: 149 °C dec.
IR (KBr): ν 2923, 1610, 1415, 942, 738 cm-1 1H NMR (400
.
MHz, CDCl3): δ 2.82 (dd, J ) 13.9, 10.8 Hz, 2H), 4,36 (dd, J
) 13.9, 3.0 Hz, 2H), 4.48-5.00 (m, 6H), 7.24-7.37 (m, 10H),
7.51 (t, J ) 7.7 Hz, 1H), 7.72 (d, J ) 7.7 Hz, 2H). 13C NMR
(100 MHz, CDCl3): δ 39.9, 63.3, 77.5, 126.1, 127.0, 127.2,
129.1, 129.4, 131.3 (satellite, J Pt-C ) 20.0 Hz), 136.2, 159.1
(satellite, J Pt-C ) 559.5 Hz), 177.1 (satellite, J Pt-C ) 105.5 Hz).
Anal. Found for C26H23N2O2Cl3Pt: C, 44.76; H, 3.31; N, 3.96.
Calcd: C, 44.81; H, 3.33; N, 4.02.
(s-Bu -P h ebox)P tCl (s-Bu -5). Yellow solids. Mp: 131 °C
dec. IR (KBr): ν 2957, 1607, 1579, 1489, 1404, 1331, 1146,
1
958, 731 cm-1. H NMR (400 MHz, CDCl3): δ 0.76 (d, J ) 6.9
(t-Bu -P h ebox)P tCl3 (t-Bu -8). Yellow solids. Single crystals
for the X-ray diffraction study were obtained from chloroform-
ether-hexane at room temperature. IR (KBr): ν 2962, 1608,
Hz, 6H), 0.99 (t, J ) 7.4 Hz, 6H), 1.16-1.38 (m, 4H), 2.71 (m,
2H), 4.51 (ddd, J ) 9.6, 6.1, 3.3 Hz, 2H), 4.71 (dd, J ) 9.0, 6.1
Hz, 2H), 4.75 (dd, J ) 9.6, 9.0 Hz, 2H), 7.14 (t, J ) 7.6 Hz,
1H), 7.35 (d, J ) 7.6 Hz, satellite, J Pt-H ) 7.4 Hz, 2H). 13C
NMR (100 MHz, CDCl3): δ 11.6, 11.9, 26.3, 35.6, 65.6 (satellite,
J Pt-C ) 34.3 Hz), 72.0 (satellite, J Pt-C ) 28.1 Hz), 122.2, 127.1
(satellite, J Pt-C ) 40.3 Hz), 128.0 (satellite, J Pt-C ) 39.2 Hz),
1
1492, 1415, 1250, 967, 738 cm-1. H NMR (400 MHz, CDCl3):
δ 1.16 (s, 18H), 4.22 (dd, J ) 9.4, 3.0 Hz, 2H), 4.95 (dd, J )
9.4, 9.2 Hz, 2H), 5.14 (dd, J ) 9.2, 3.0 Hz, 2H), 7.49 (t, J ) 7.7
Hz, 1H), 7.70 (d, J ) 7.7 Hz, 2H). 13C NMR (100 MHz,
CDCl3): δ 26.6, 35.5, 70.9 (satellite, J Pt-C ) 18.8 Hz), 76.6
(satellite, J Pt-C ) 18.3 Hz), 126.0, 126.7, 131.2 (satellite, J Pt-C
) 20.4 Hz), 157.2 (satellite, J Pt-C ) 557.6 Hz), 178.8 (satellite,
J Pt-C ) 101.6 Hz). Anal. Found for C20H27N2O2Cl3Pt: C, 38.14;
H, 4.32; N, 4.43. Calcd: C, 38.20; H, 4.33; N, 4.45.
[(i-P r -P h ebox)P d(H2O)](BF4) (i-P r -9). White solids. Single
crystals for the X-ray diffraction study were obtained from
benzene-acetone at room temperature. Mp: 244-246 °C dec.
IR (KBr): ν 3438, 2925, 1618, 1487, 1403, 1137, 1057, 736
cm-1. 1H NMR (400 MHz, CD3OD): δ 0.97 (d, J ) 6.8 Hz, 6H),
1.05 (d, J ) 7.1 Hz, 6H), 2.17 (qqd, J ) 7.1, 6.8, 3.8 Hz, 2H),
4.34 (ddd, J ) 8.7, 6.9, 3.8 Hz, 2H), 4.84-4.89 (m, 4H), 7.36
(t, J ) 7.6 Hz, 1H), 7.46 (d, J ) 7.6 Hz, 2H). 13C NMR (100
MHz, CDCl3): δ 14.9, 18.5, 31.4, 68.0, 73.1, 126.7, 128.9, 130.9,
163.8, 175.4. Anal. Found for C18H25N2O3B1F4Pd: C, 42.01; H,
4.81; N, 5.45. Calcd: C, 42.34; H, 4.93; N, 5.49.
161.2 (satellite, J Pt-C ) 864.8 Hz), 178.9 (satellite, J Pt-C
)
193.8 Hz). Anal. Found for C20H27N2O2ClPt: C, 42.97; H, 4.88;
N, 4.95. Calcd: C, 43.05; H, 4.88; N, 5.02.
(t-Bu -P h ebox)P tCl (t-Bu -5). Yellow solids. Mp: 283-285
°C dec. IR (KBr): ν 2925, 1579, 1489, 1403, 1249, 965, 670
1
cm-1. H NMR (400 MHz, CDCl3): δ 1.04 (s, 18H), 4.11 (dd, J
) 8.4, 2.0 Hz, 2H), 4.67 (dd, J ) 9.2, 8.4 Hz, 2H), 4.95 (dd, J
) 9.2, 2.0 Hz, 2H), 7.18 (t, J ) 7.6 Hz, 1H), 7.38 (d, J ) 7.6
Hz, 1H). 13C NMR (100 MHz, CDCl3): δ 26.5, 35.5, 70.2
(satellite, J Pt-C ) 34.2 Hz), 74.4 (satellite, J Pt-C ) 26.2 Hz),
122.2, 127.4 (satellite, J Pt-C ) 38.7 Hz), 127.6 (satellite, J Pt-C
) 35.6 Hz), 159.7 (satellite, J Pt-C ) 852.4 Hz), 186.2 (satellite,
J Pt-C ) 186.2 Hz). Anal. Found for C20H27N2O2ClPt: C, 43.06;
H, 5.07; N, 5.05. Calcd: C, 43.05; H, 4.88; N, 5.02.
(i-P r -P h ebox)P t(OTf) (i-P r -6). Yellow solids. Mp: 223-
224 °C dec. IR (KBr): ν 2975, 1610, 1550, 1490, 1390, 1280,
[(i-P r -P h ebox)P t (H2O)](BF 4) (i-P r -10). Yellow solids.
Single crystals for the X-ray diffraction study were obtained
from benzene-acetone at room temperature. Mp: 197-199
°C dec. IR (KBr): ν 3401, 2960, 1612, 1582, 1490, 1407, 1127,
1
1250, 1040, 650 cm-1. H NMR (400 MHz, CDCl3): δ 0.80 (d,
J ) 7.1 Hz, 6H), 0.96 (d, J ) 7.1 Hz, 6H), 2.52 (dsept, J ) 7.1,
3.3 Hz, 2H), 4.47 (ddd, J ) 9.8, 9.1, 3.3 Hz, 2H), 4.78 (dd, J )
9.1, 6.6 Hz, 2H), 4.80 (dd, J ) 9.8, 6.6 Hz, 2H), 7.19 (t, J ) 7.7
Hz, 1H), 7.33 (d, J ) 7.7 Hz, 2H). 13C NMR (100 MHz,
CDCl3): δ 13.9, 18.5, 29.1, 66.8 (satellite, J Pt-C ) 31.5 Hz),
72.2 (satellite, J Pt-C ) 25.8 Hz), 120 0 (q, J C-F ) 317.1 Hz),
123.4, 127.5 (satellite, J Pt-C ) 46.3 Hz), 128.0 (satellite, J Pt-C
) 40.1 Hz), 151.7 (satellite, J Pt-C ) 991.0 Hz), 178.1 (satellite,
J Pt-C ) 214.7 Hz). Anal. Found for C19H23N2O5SF3Pt: C, 35.43;
H, 3.77; N, 4.25. Calcd: C, 35.46; H, 3.60; N, 4.35.
1
1063, 965, 738 cm-1. H NMR (400 MHz, CD3OD): δ 0.83 (d,
J ) 6.8 Hz, 6H), 0.97 (d, J ) 7.2 Hz, 6H), 2.17 (qqd, J ) 7.2,
6.8, 3.2 Hz, 2H), 4.30 (dt, J ) 3.2, 7.6 Hz, 2H), 4.77-4.92 (m,
4H), 7.25 (t, J ) 7.6 Hz, 1H), 7.39 (d, J ) 7.6 Hz, 2H). 13C
NMR (100 MHz, CD3OD): δ 14.3, 18.3, 31.1, 68.0 (satellite,
J Pt-C ) 34.0 Hz), 73.7 (satellite, J Pt-C ) 27.0 Hz), 125.2, 128.7
(satellite, J Pt-C ) 42.0 Hz), 129.3, 152.8, 180.1 (satellite, J Pt-C
) 207.0 Hz). Anal. Found for C18H25N2O3BF4Pt: C, 36.13; H,
4.26; N, 4.69. Calcd: C, 36.08; H, 4.20; N, 4.67.
[(P h -P h ebox)P t(H2O)](BF 4) (P h -10). Yellow solids. Mp:
175 °C dec. IR (KBr): ν 3494, 3032, 1609, 1490, 1407, 1331,
1060, 933, 701 cm-1. Anal. Found for C24H21N2O3BF4Pt: C,
43.26; H, 3.27; N, 4.26. Calcd: C, 43.20; H, 3.17; N, 4.20.
[(Bn -P h ebox)P t(H2O)](BF 4) (Bn -10). Yellow solids. Mp:
193-194 °C dec. IR (KBr): ν 3213, 2929, 1609, 1491, 1408,
1084, 951, 735 cm-1. Anal. Found for C26H25N2O3BF4Pt: C,
44.92; H, 3.78; N, 3.89. Calcd: C, 44.91; H, 3.62; N, 4.03.
[(s-Bu -P h ebox)P t(H2O)](BF 4) (s-Bu -10). Yellow solids.
Mp: 92 °C dec. IR (KBr): ν 3404, 2961, 1659, 1611, 1584, 1490,
1406, 1300, 1064, 738 cm-1. Anal. Found for C20H29N2O3BF4-
Pt: C, 38.45; H, 4.68; N, 4.48. Calcd: C, 38.29; H, 4.66; N,
4.47.
(i-P r -P h ebox)P t(OCOCF 3) (i-P r -7). Yellow solids. Mp:
273 °C dec. IR (KBr): ν 2956, 1604, 1485, 1404, 1331, 1149,
1
737 cm-1. H NMR (400 MHz, CDCl3): δ 0.83 (d, J ) 7.0 Hz,
6H), 0.93 (d, J ) 7.10 Hz, 6H), 2.23 (qqd, J ) 7.1, 7.0, 3.7 Hz,
2H), 4.42 (ddd, J ) 9.7, 6.0, 3.7 Hz, 2H), 4.74 (dd, J ) 9.2, 6.0
Hz, 2H), 4.78 (dd, J ) 9.7, 9.2 Hz, 2H), 7.16 (t, J ) 7.7 Hz,
1H), 7.34 (d, J ) 7.7 Hz, 2H). 13C NMR (100 MHz, CDCl3): δ
14.5, 18.5, 29.7, 67.4 (satellite, J Pt-C ) 31.8 Hz), 72.4 (satellite,
J Pt-C ) 27.3 Hz), 117.2 (q, J C-F ) 290.7 Hz), 122.7, 127.3
(satellite, J Pt-C ) 41.0 Hz), 128.2 (satellite, J Pt-C ) 38.3 Hz),
157.0 (satellite, J Pt-C ) 900.3 Hz), 162.6 (J C-F ) 35.7 Hz), 178.9
(satellite, J Pt-C ) 201.0 Hz). Anal. Found for C20H23N2O4F3Pt:
C, 39.63; H, 3.87; N, 4.64. Calcd: C, 39.54; H, 3.82; N, 4.61.
(i-P r -P h ebox)P t Cl3 (i-P r -8). Yellow solids. Mp: 133 °C
dec. IR (KBr): ν 2925, 1614, 1493, 1415, 924, 737 cm-1 1H
.
[(t-Bu -P h ebox)P t(H2O)](BF 4) (t-Bu -10). Yellow solids.
Mp: 197 °C dec. IR (KBr): ν 3414, 2969, 1585, 1492, 1414,
1332, 1262, 1064, 971, 742 cm-1. Anal. Found for C20H29N2O3-
BF4Pt: C, 38.29; H, 4.69; N, 4.51. Calcd: C, 38.29; H, 4.66; N,
4.47.
[(i-P r -P h ebox)P tCl2(H2O)](BF 4) (i-P r -11). Yellow solids.
Mp: 106-108 °C dec. IR (KBr): ν 3486, 2965, 1615, 1496,
1419, 1258, 1082, 923, 740 cm-1. Anal. Found for C18H25N2O3-
NMR (400 MHz, CDCl3): δ 0.99 (d, J ) 6.7 Hz, 6H), 1.00 (d,
J ) 7.2 Hz, 6H), 3.03 (dqq, J ) 2.9, 7.2, 6.7 Hz, 2H), 4.57 (ddd,
J ) 10.3, 6.6, 2.90 Hz, 2H), 4.94 (dd, J ) 9.1, 6.6 Hz, 2H),
5.00 (dd, J ) 10.3, 9.1 Hz, 2H), 7.48 (t, J ) 7.7 Hz, 1H), 7.68
(d, J ) 7.7 Hz, 2H). 13C NMR (100 MHz, CDCl3): δ 14.8, 19.3,
28.1, 66.8 (satellite, J Pt-C ) 20.1 Hz), 73.1 (satellite, J Pt-C
)
21.5 Hz), 126.0 (satellite, J Pt-C ) 8.5 Hz), 126.8, 131.1
(satellite, J Pt-C ) 21.7 Hz), 158.6 (satellite, J Pt-C ) 569.8 Hz),

Bis(oxazolinyl)phenyl-Derived Pd and Pt Complexes
Organometallics, Vol. 21, No. 16, 2002 3415
BCl2F4Pt‚H2O: C, 31.55; H, 4.08; N, 3.82. Calcd: C, 31.41; H,
3.95; N, 4.07.
4-p-Tolu en esu lfon yl-5-m esityl-2-oxa zolin e (12e). trans
isomer: white solid. Mp: 98 °C. [R]D22-112.6° (c 1.00, THF)
for 71% ee. IR (KBr): ν 2965, 2874, 1616, 1315, 1150, 659 cm-1
.
Gen er a l P r oced u r e for th e Asym m etr ic Ald ol-Typ e
Con d en sa tion of Ald eh yd es a n d TosMIC Ca ta lyzed w ith
[(P h ebox)P tII(H2O)](BF 4) Com p lexes. To a solution of the
[(Phebox)PtII(H2O)](BF4) complex 10 (0.01 mmol), aldehyde (0.6
mmol), and TosMIC (1; 97.6 mg, 0.5 mmol) in THF (2 mL)
was added N,N-diisopropylethylamine (8.7 µL, 0.05 mmol) at
0 °C. After it was stirred for 24 h at that temperature, the
reaction mixture was filtered through a pad of Celite and
Florisil, and then the filtrate was concentrated under reduced
pressure. Purification by silica gel chromatography (benzene
in 1% of triethylamine) gave the 2-oxazoline: the trans/cis ratio
was determined by 1H NMR analysis, and the enantioselec-
tivity was determined by chiral HPLC analysis.
1H NMR (400 MHz, CDCl3): δ 2.28 (s, 3H), 2.33 (s, 6H), 2.46
(s, 3H), 5.06 (dd, J ) 8.2, 1.6 Hz, 1H), 6.42 (d, J ) 8.2 Hz,
1H), 6.89 (s, 1H), 7.10 (d, J ) 1.6 Hz, 1H), 7.38 (d, J ) 8.2 Hz,
2H), 7.84 (d, J ) 8.2 Hz, 2H). 13C NMR (100 MHz, CDCl3): δ
20.1, 21.0, 21.8, 76.9, 91.0, 129.6, 129.7, 129.9, 130.6, 133.6,
137.8, 139.3, 145.7, 159.3. Anal. Found for C19H21NO3S: C,
66.40; H, 6.16; N, 3.99. Calcd: C, 66.45; H, 6.16; N, 4.08%.
Daicel CHIRALPAK AD, UV detector 254 nm, 5:1 hexane-i-
PrOH, flow rate 1.0 mL/min. tR ) 8.5 min (major), 11.7 min
(minor).
4-(p-Tolylsu lfon yl)-5-(r-n aph th yl)-2-oxazolin e (12f). Data
are as follows for the trans isomer. White solid. Mp: 107 °C.
19
[R]D ) -19.2° (c 0.91, THF) for 53% ee. IR (KBr): ν 3047,
4-(p-Tolylsu lfon yl)-5-p h en yl-2-oxa zolin e (12a ). Data are
2977, 1616, 1511, 1305, 1113, 794, 663 cm-1 1H NMR (400
.
27
as follows for the trans isomer. White solid. Mp: 122 °C. [R]D
) -137.8° (c 0.75, THF) for 68% ee; lit.4 [R]D20 ) +212° (c 1.0-
1.1, THF) for 86% ee (4R,5R). IR (KBr): ν 3079, 2956, 1612,
MHz, CDCl3): δ 2.44 (s, 3H), 5.20 (dd, J ) 5.1, 1.5 Hz, 1H),
6.80 (d, J ) 5.1 Hz, 1H), 7.34-7.42 (m, 4H), 7.46 (dd, J ) 8.1,
7.3 Hz, 1H), 7.58 (dd, J ) 8.2, 7.0 Hz, 1H), 7.65 (dd, J ) 8.4,
7.0 Hz, 1H), 7.86 (d, J ) 8.4 Hz, 2H), 7.89 (d, J ) 8.1 Hz, 1H),
7.92 (d, J ) 8.2 Hz, 1H), 8.35 (d, J ) 8.4 Hz, 1H). 13C NMR
(100 MHz, CDCl3): δ 21.8, 77.8, 91.4, 122.9, 123.9, 125.2,
126.4, 127.3, 129.2, 129.6 (2C), 129.9, 130.1, 132.1, 133.4,
134.0, 145.7, 160.1. Anal. Found for C20H17NO3S: C, 68.17;
H, 5.06; N, 3.95. Calcd: C, 68.36; H, 4.88; N, 3.99. Daicel
CHIRALPAK AD, UV detector 254 nm, 5:1 hexane-i-PrOH,
flow rate 1.0 mL/min: tR ) 15.8 min (major), 24.8 min (minor).
4-(p-Tolylsu lfon yl)-5-(ter t-bu tyl)-2-oxazolin e (12g). Data
are as follows for the trans isomer. White solid. Mp: 120 °C.
1494, 1311, 1154, 1113, 948, 702 cm-1 1H NMR (400 MHz,
.
CDCl3): δ 2.45 (s, 3H), 5.04 (dd, J ) 5.9, 1.6 Hz, 1H), 6.05 (d,
J ) 5.9 Hz, 1H), 7.22 (d, J ) 1.6 Hz, 1H), 7.28-7.46 (m, 7H),
7.85 (d, J ) 8.4 Hz, 2H). 13C NMR (100 MHz, CDCl3): δ 21.9,
79.4, 92.6, 125.3, 129.1, 129.2, 129.6, 130.0, 133.2, 137.8, 145.8,
159.6. Daicel CHIRALCEL OD-H, UV detector 254 nm, 5:1
hexane-i-PrOH, flow rate 0.5 mL/min: tR ) 19.1 min (4R,5R),
1
25.5 min (4S,5S). Data are as follows for the cis complex. H
NMR (400 MHz, CDCl3): δ 2.42 (s, 3H), 5.37 (dd, J ) 10.2,
1.9 Hz, 1H), 5.89 (d, J ) 10.2 Hz, 1H), 7.28-7.46 (m, 8H), 7.61
(d, J ) 8.2 Hz, 2H).
[R]D ) -251.1° (c 0.8, THF) for 75% ee; lit.4 [R]D ) +321°
(c 1.0-1.1, THF) for 86% ee (4R,5R). IR (KBr): ν 2964, 1672,
22
20
4-p -Tolu en esu lfon yl-5-(p -ch lor op h en yl)-2-oxa zolin e
(12b). Data are as follows for the trans isomer. White solid.
1615, 1472, 1308, 1153, 1129, 960, 707 cm-1 1H NMR (400
.
Mp: 42 °C. [R]D21 ) -86.3° (c 1.00, THF) for 25% ee, lit.4 [R]D
20
MHz, CDCl3): δ 0.94 (s, 9H), 2.46 (s, 3H), 4.76 (dd, J ) 5.5,
0.4 Hz, 1H), 4.83 (dd, J ) 5.5, 1.5 Hz, 1H), 7.03 (dd, J ) 1.5,
0.4 Hz, 1H), 7.38 (d, J ) 8.3 Hz, 2H), 7.83 (d, J ) 8.3 Hz, 2H).
13C NMR (100 MHz, CDCl3): δ 21.8, 24.5, 34.1, 86.3, 86.5,
129.6, 129.9, 133.4, 145.5, 159.9. Daicel CHIRALCEL OD-H,
UV detector 254 nm, 5:1 hexane-i-PrOH, flow rate 1.0 mL/
min: tR ) 17.3 min (4R,5R), 19.6 min (4S,5S).
) +200° (c 1.0-1.1, THF) for 89% ee (4R,5R). IR (KBr): ν 1681,
1
1622, 1564, 1495, 1401, 1315, 1145, 1089, 819, 650 cm-1. H
NMR (400 MHz, CDCl3): δ 2.45 (s, 3H), 4.98 (dd, J ) 6.0, 2.0
Hz, 1H), 6.02 (d, J ) 6.0 Hz, 1H), 7.21 (d, J ) 2.0 Hz, 1H),
7.27 (d, J ) 8.8 Hz, 2H), 7.37 (d, J ) 8.8 Hz, 2H), 7.38 (d, J )
8.0 Hz, 2H), 7.84 (d, J ) 8.0 Hz, 2H). 13C NMR (100 MHz,
CDCl3): δ 21.8, 78.7, 92.6, 126.6, 129.4, 129.6, 130.0, 133.0,
135.0, 136.3, 145.9, 159.3. Daicel CHIRALCEL OD-H, UV
detector 254 nm, 5:1 hexane-i-PrOH, flow rate 0.5 mL/min:
tR ) 19.5 min (4R,5R), 26.0 min (4S,5S).
4-(Ca r bom et h oxy)-5-p h en yl-2-oxa zolin e
(13).
IR
(KBr): ν 2954, 1742, 1626, 1438, 1205, 1106, 951, 756, 700
cm-1. Data are as follows for the trans isomer. [R]D22 ) -73.3°
(c 1.2, THF) for 36% ee; lit.2a [R]D ) +297° (c 1.2, THF) for
20
4-(p -Tolylsu lfon yl)-5-(p -m et h oxyp h en yl)-2-oxa zolin e
96% ee (4S,5R). 1H NMR (400 MHz, CDCl3): δ 3.84 (s, 3H),
4.63 (dd, J ) 7.9, 2.4 Hz, 1H), 5.69 (d, J ) 7.9 Hz, 1H), 7.10
(d, J ) 2.4 Hz, 1H), 7.30-7.44 (m, 5H). 13C NMR (100 MHz,
CDCl3): δ 53.0, 75.5, 82.3, 125.7, 128.9, 129.1, 139.0, 156.4,
171.0. Daicel CHIRALPAK AD, UV detector 254 nm, 9:1
hexane-i-PrOH, flow rate 1.0 mL/min: tR ) 11.7 min (4R,5S),
16.1 min (4S,5R). Astec Chiraldex G-TA (30 M), column
temperature 145 °C, detection FID: tR ) 30.2 min (4S,5R),
31.5 min (4R,5S). Data are as follows for the cis isomer. 1H
NMR (400 MHz, CDCl3): δ 3.20 (s, 3H), 5.09 (dd, J ) 11.2,
2.0 Hz, 1H), 5.74 (d, J ) 11.2 Hz, 1H), 7.18-7.42 (m, 6H). 13C
NMR (100 MHz, CDCl3): δ 51.8, 72.6, 82.0, 126.3, 128.4, 128.9,
135.2, 157.6, 169.0. Daicel CHIRALPAK AD, UV detector 254
nm, 9:1 hexane-i-PrOH, flow rate 1.0 mL/min: tR ) 14.8 min
(major), 19.4 min (minor).
X-r a y Str u ctu r e Deter m in a tion a n d Deta ils of Refin e-
m en t. X-ray-quality crystals of i-Pr-4, t-Bu-8, i-Pr-9, and (s-
Bu-Phebox)RhIIICl2(H2O) were obtained directly from the
preparations described above and mounted in glass capillaries.
Diffraction experiments were performed on a Rigaku AFC-7R
four-circle diffractometer equipped with graphite-monochro-
mated Mo KR radiation; λ ) 0.710 69 Å. The lattice parameters
and orientation matrixes were obtained and refined from 25
machine-centered reflections with 29.20 < 2θ < 29.94° for i-Pr-
4, from 25 machine-centered reflections with 29.73 < 2θ <
29.99° for t-Bu-8, from 24 machine-centered reflections with
29.24 < 2θ < 29.93° for i-Pr-9, and from 25 machine-centered
(12c). Data are as follows for the trans isomer. White solid.
Mp: 128 °C. [R]D ) -163.7° (c 1.04, THF) for 31% ee; lit.4
22
20
[R]D ) +239° (c 1.0-1.1, THF) for 79% ee (4R,5R). IR (KBr):
ν 2939, 1617, 1514, 1300, 1259, 1146, 1101, 823, 708, 661 cm-1
.
1H NMR (400 MHz, CDCl3): δ 2.35 (s, 3H), 3.71 (s, 3H), 4.93
(dd, J ) 6.0, 1.6 Hz, 1H), 5.89 (d, J ) 6.0 Hz, 1H), 6.81 (d, J
) 8.8 Hz, 2H), 7.10 (d, J ) 1.6 Hz, 1H), 7.14 (d, J ) 8.8 Hz,
2H), 7.28 (d, J ) 8.0 Hz, 2H), 7.74 (d, J ) 8.0 Hz, 2H). 13C
NMR (100 MHz, CDCl3): δ 21.8, 55.4, 79.5, 92.4, 114.6, 127.0,
129.6, 129.8, 129.9, 133.2, 145.7, 159.6, 160.3. Daicel CHIRAL-
CEL OD-H, UV detector 254 nm, 5:1 hexane-i-PrOH,
flow rate 0.5 mL/min: tR ) 16.7 min (4R,5R), 24.7 min
(4S,5S).
4-(p -Tolylsu lfon yl)-5-(o-m et h oxyp h en yl)-2-oxa zolin e
(12d ). Data are as follows for the trans isomer. White solid.
22
Mp: 32-38 °C. [R]D ) -166.3° (c 0.95, THF) for 70% ee. IR
(KBr): ν 3074, 2945, 1614, 1494, 1148, 1117, 814, 758 cm-1
.
1H NMR (400 MHz, CDCl3): δ 2.45 (s, 3H), 3.80 (s, 3H), 5.17
(dd, J ) 6.2, 1.6 Hz, 1H), 6.11 (d, J ) 6.2 Hz, 1H), 6.91 (d, J
) 8.4 Hz, 1H), 6.97 (td, J ) 7.5, 1.1 Hz, 1H), 7.11 (d, J ) 1.6
Hz, 1H), 7.24 (dd, J ) 7.5, 1.7 Hz, 1H), 7.35-7.39 (m, 3H),
7.85 (d, J ) 8.2 Hz, 2H). 13C NMR (100 MHz, CDCl3): δ 21.8,
55.5, 77.9, 90.9, 111.2, 120.9, 124.7, 129.2, 129.7, 129.9, 131.2,
133.6, 145.5, 157.5, 159.3. Anal. Found for C17H17NO4S: C,
61.70; H, 5.26; N, 4.16. Calcd: C, 61.61; H, 5.17; N, 4.23. Daicel
CHIRALPAK AD, UV detector 254 nm, 5:1 hexane-i-PrOH,
flow rate 1.0 mL/min: tR ) 22.9 min (major), 29.7 min (minor).

3416 Organometallics, Vol. 21, No. 16, 2002
Motoyama et al.
Ta ble 5. Cr ysta llogr a p h ic Da ta for i-P r -4‚H2O, t-Bu -8, i-P r -9, a n d (s-Bu -P h ebox)Rh IIICl2(H2O).
i-Pr-4‚H2O
t-Bu-8
i-Pr-9
(s-Bu-Phebox)RhCl2(H2O)
formula
fw
C9H12.50NO1.50Cl0.50Pd0.50
229.63
C20H27N2O2Cl3Pt
628.89
C18H25N2O3BF4Pd
510.61
C40H58N4O6Cl4Rh2
1038.54
cryst syst
space group
cell constants
a, Å
b, Å
c, Å
orthorhombic
P21212
monoclinic
P21
orthorhombic
P21212
monoclinic
P21
14.536(2)
5.947(2)
10.954(3)
96.26(1)
947.0(6)
4
7.538(2)
15.881(1)
9.6968(9)
103.01(2)
1154.0(3)
2
14.711(2)
6.093(2)
11.719(2)
12.440(4)
14.824(4)
12.761(3)
â, deg
V, Å3
1050.4(6)
2
1.614
2292.9(9)
2
1.504
Z
D
calcd, g cm-3
1.611
1.810
F(000)
468
11.40
Mo KR; 0.710 69
23.0
612
64.20
Mo KR; 0.710 69
23.0
516
9.40
Mo KR; 0.710 69
23.0
1064
9.98
Mo KR; 0.710 69
23.0
µ(Mo KR), cm-1
radiation; λ, Å
temp, °C
2θmax, deg
55.0
ω-2θ
55.1
ω-2θ
55.0
ω-2θ
1.31 + 0.30 tanθ
1428
55.1
ω-2θ
scan type
scan width, deg
total no. of data collected
no. of unique data
no. of obsd rflns
no. of variables
residuals: R; Rw
1.31 + 0.30 tan θ
1.10 + 0.30 tan θ
0.94 + 0.30 tan θ
1447
2951
5735
1298 (Rint ) 0.731)
854 (I > 3σ)
116
2754 (Rint ) 0.017)
2555 (I > 3σ)
252
5493 (Rint ) 0.028)
3727 (I > 3σ)
504
1257 (I > 3σ)
134
0.052; 0.069
0.040; 0.047
0.026; 0.033
0.043; 0.048
reflections with 29.56 < 2θ < 29.99° for (s-Bu-Phebox)RhIII
-
were drawn with ORTEP using 30% probability ellipsoids.
Crystallographic data (excluding structure factors) for the
structures reported in this paper have been deposited with the
Cambridge Crystallographic Data Centre as supplementary
publication Nos. CCDC-121108 (i-Pr-4), CCDC-178928 (i-Pr-
5), CCDC-180035 (t-Bu-8), CCDC-180036 (i-Pr-9), CCDC-
178929 (i-Pr-10), and CCDC-180663 ((s-Bu-Phebox)RhCl2-
(H2O)). Copies of the data can be obtained free of charge on
application to the CCDC, 12 Union Road, Cambridge CB21EZ,
U.K. (fax, (+44)1223-336-033; e-mail, deposit@ccdc.cam.ac.uk).
Cl2(H2O). Intensity data were collected using a ω-2θ scan
technique, and three standard reflections were recorded every
150 reflections. The data were corrected for Lorentz and
polarization effects. Relevant crystal data are given in Table
5. The structure was solved by heavy-atom Patterson meth-
ods17 and expanded using Fourier techniques.18 The non-
hydrogen atoms were refined anisotropically. Hydrogen atoms
were included but not refined. The final cycle of full-matrix
least-squares refinement was based on 854 observed reflections
(I > 3σ(I)) and 116 variable parameters for i-Pr-4, on 2555
observed reflections (I > 3σ(I)) and 252 variable parameters
for t-Bu-8, on 1257 observed reflections (I > 3σ(I)) and 134
variable parameters for i-Pr-9, and on 3727 observed reflec-
tions (I > 3σ(I)) and 504 variable parameters for (s-Bu-
Phebox)RhIIICl2(H2O). Neutral atom scattering factors were
taken from Cromer and Waber.19 All calculations were per-
formed using the teXsan20 crystallographic software package.
Final refinement details are collected in Table 5 and the
numbering schemes employed are shown in Figure 1, which
Ack n ow led gm en t. This work was partly supported
by a Grant-in-Aid for Scientific Research from the
Ministry of Education, Culture, Sports, Science and
Technology of J apan.
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal
structure parameters and details of data collection, bond
angles and distances, and atomic positional and thermal
parameters for i-Pr-4, t-Bu-8, i-Pr-9, and (s-Bu-Phebox)RhIII
-
(17) Fan, H. F. SAPI91: Structure Analysis Programs with Intel-
ligent Control; Rigaku Corp., Tokyo, J apan, 1991.
(18) DIRDIF92: Beurskens, P. T.; Admiraal, G.; Beurskens, G.;
Bosman, W. P.; Garcia-Granda, S.; Gould, R. O.; Smits, J . M. M.;
Smykalla, C. The DIRDIF Program System; Technical Report of the
Crystallography Laboratory; University of Nijmegen, Nijmegen, The
Netherlands, 1992.
Cl2(H2O). This material is available free of charge via the
Internet at http://pubs.acs.org.
OM020274Q
(19) Cromer, D. T.; Waber, J . T. International Tables for X-ray
Crystallography; Kynoch Press: Birmingham, U.K., 1974; Vol. 4.
(20) teXane: Crystal Structure Analysis Package; Molecular Struc-
ture Corp., The Woodlands, TX, 1985, 1992.