Chiral phosphinooxathiane ligands for catalytic asymmetric Diels-Alder reaction

Article abstract of DOI:10.1021/jo0201474

Chiral cationic palladium-phosphinooxathiane complexes have been found to be effective catalysts for enantioselective Diels-Alder (DA) reaction of cyclopentadiene with acyl-1,3-oxazolidin-2-ones to give the corresponding DA adducts in good yield and high enantioselectivity up to 93% ee.

Full text of DOI:10.1021/jo0201474

POT ligands in the enantioselective DA reactions. In this
paper, we report a detailed investigation of DA reactions
of cyclopentadiene with acryloyl- and fumaroyl-1,3-ox-
azolidin-2-ones (6a and 6b) using cationic Pd(II)- and
Pt(II)-POT complexes 12a -g and 14. Especially, it is
important that the more conformationally constrained
cationic complexes 12e-g (M ) Pd, X ) SbF6) that were
derived from newly modified ligands 2-4 gave fairly good
results for enantioselectivity (Scheme 1).
Ch ir a l P h osp h in ooxa th ia n e Liga n d s for
Ca ta lytic Asym m etr ic Diels-Ald er
Rea ction
Hiroto Nakano,*,† Yuichiro Suzuki,† Chizuko Kabuto,‡
Reiko Fujita,† and Hiroshi Hongo†
Tohoku Pharmaceutical University, 4-4-1 Komatsushima,
Aoba-ku, Sendai 981-8558, J apan and Instrumental
Analysis Center for Chemistry, Graduate School of Science,
Tohoku University, Aoba, Aramaki,
Aoba-ku, Sendai 980-8578, J apan
Resu lts a n d Discu ssion
hnakano@tohoku-pharm.ac.jp
Received March 4, 2002
Syn th esis of P h osp h in ooxa th ia n e Liga n d s. Three
new chiral ligands 2-4 bearing 3-tolyl, 3,5-xylyl, and
1-naphthyl moieties were synthesized by the palladium-
catalyzed cross-coupling type reaction as shown in Scheme
2. The reactions of 2-bromobenzaldehyde 8 with (3-
CH3C6H4)2P(O)H, [3,5-(CH3)2C6H4]2P(O)H, and (1-C10H4)2P-
(O)H using Pd(OAc)2, a catalytic amounts of dppp [1,3-
bis(diphenylphosphino)propane], and i-Pr2NEt in DMSO
at 150 °C9 gave the phosphine oxides 9a -c, respectively.
And then the condensations of commercially available
(1S)-(-)-10-mercaptoisoborneol with 9a -c in refluxing
benzene afforded the products 10a -c in 91, 85, and 87%
yields. The products 10a -c were reduced with HSiCl3
and Et3N9 to give the desired chiral ligands 2-4 in 78,
83, and 65% yields.
Asym m et r ic Diels-Ald er R ea ct ion . The chiral
PdCl2-, PtCl2-POT complexes 11a -e and 13 were easily
prepared by the reactions of Scheme 3 in good yields. For
catalytic DA reactions, we first examined the reaction of
cyclopentadiene and acryloyl-1,3-oxazolidin-2-one 6a in
the presence of 20 mol % of catalysts 11a and 13 at -78
°C; however, these reactions provided the DA adduct 7a
in low chemical isolated yields (11a : 18%, 13: 15%) and
no enantioselectivity. To increase the reactivity of com-
plexes, various counterion effects were tested using the
complex 11a (Scheme 3). The catalysts 12a -c (X ) OTf,
ClO4, SbF6) were prepared by the reaction of 11a (1 equiv)
and the corresponding AgX (2 equiv) in dry CH2Cl2 at rt
for 1 h under argon.
Abstr a ct: Chiral cationic palladium-phosphinooxathiane
complexes have been found to be effective catalysts for enan-
tioselective Diels-Alder (DA) reaction of cyclopentadiene
with acyl-1,3-oxazolidin-2-ones to give the corresponding DA
adducts in good yield and high enantioselectivity up to 93%
ee.
The asymmetric Diels-Alder (DA) reaction is an im-
portant and versatile reaction in synthetic organic chem-
istry for preparation of an optically active compound,1
for which many groups have reported2 an enantioselective
version of this reaction with a chiral catalyst formed from
chiral ligands and Lewis acids. Of the successful ligands
to give high enantioselectivity for the DA reaction, C2-
symmetricalbis-oxazolines,3 phosphinooxazolines,4 BINOL,5
and BINAP6 ligands have been so far reported. Most
recently, we developed S-P type, chiral phosphinoox-
athiane (POT) ligands 1 and 5 and found that the Pd
complex of ligand 1 works as an effective catalyst of Pd-
catalyzed asymmetric allylic alkylation and amination.8
These results prompted us to investigate the utility of
† Tohoku Pharmaceutical University.
‡ Tohoku University.
(1) (a) Corey, E. J .; Weinshenker, N. M.; Schaaf, T. K.; Huber, W.
J . Am. Chem. Soc. 1969, 91, 5675-5677. (b) Oppolzer, W. Ang. Chem.,
Int. Ed. Engl. 1984, 23, 876-889. (c) Ohfune, Y.; Tomita, M. J . Am.
Chem. Soc. 1991, 104, 3511-3513. (d) Matsuo, G.; Miki, Y.; Nakata,
M.; Matsumura, S.; Toshima, K. J . Chem. Soc., Chem. Commun. 1996,
225-226.
(2) (a) Kagan, H. B.; Riant, O. Chem. Rev. 1992, 92, 1007-1019. (b)
Diaz, L. C. J . Braz. Chem. Soc. 1997, 8, 289-332. (c) Evans, D. A.;
J ohnson, J . S. In Comprehensive Asymmetric Catalysis; J acobsen, E.
N.; Pfaltz, A.; Yamamoto, H., Eds.; Springer-Verlag: Heidelbelg, 1999;
Vol. 3, pp 1178-1235.
(3) (a) Corey, E. J .; Imai, N.; Zhang, H.-Y. J . Am. Chem. Soc. 1991,
113, 728-729. (b) Corey, E. J .; Ishihara, K. Tetrahedron Lett. 1992,
33, 6807-6810. (c) Kanemasa, S.; Oderaotoshi, Y.; Yamamoto, H.;
Tanaka, J .; Wada, E. J . Org. Chem. 1997, 62, 6454-6455. (d) Ghosh,
A. K.; Mathivanan, P.; Cappiello, J . Tetrahedron: Asymmetry 1998,
9, 1-45. (e) Ghosh, A. K.; Cho, H.; Cappiello, J . Tetrahedron: Asym-
metry 1998, 9, 3687-3691. (f) Evans, D. A.; Miller, S. J .; Lectka, T.;
Matt, P. V. J . Am. Chem. Soc. 1999, 121, 7559-7573. (g) Evans, D.
A.; Barnes, D. M.; J ohnson, J . S.; Lectka, T.; Matt, P. V.; Miller, S. J .;
Murry, J . A.; Norcross, R. D.; Shaughnessy, E. A.; Campos, K. R. J .
Am. Chem. Soc. 1999, 121, 7582-7594.
The DA reactions of cyclopentadiene (5 equiv) with
dienophile 6a (1 equiv) using the prepared catalysts
12a -c (20 mol %) in dry CH2Cl2 at a low temperature
gave the DA adduct. The absolute configuration of DA
adduct 7a (2R-configuration)10 was determined on basis
of comparison of the optical rotations with the literature.
The results are summarized in Table 1. The reaction
catalyzed by 12a (X ) OTf) gave the DA adduct 7a in
(7) (a) Barbaro, P.; Currao, A.; Herrmann, J .; Nesper, R.; Pregosin,
P.; Salzmann, R. Organometallics 1996, 15, 1879-1888. (b) Albinati,
A.; Pregosin, P.; Wick, K. Organometallics 1996, 15, 2419-2421. (c)
Albinati, A.; Eckert, J .; Pregosin, P.; Ruegger, H.; Salzmann, R.;
Stossel, C. Organometallics 1997, 16, 579-590. (d) Hiraoka, M.;
Nishikawa, A.; Morimoto, T.; Achiwa, K. Chem. Pharm. Bull. 1998,
46, 704-706. (e) Hauptman, E.; Shapiro, R.; Marshall, W. Organome-
tallics 1998, 17, 4976-4982. (f) Evans, D. A.; Campos, K. R.; Tedrow,
J . S.; Micheal, F. E.; Gagne, M. R. J . Org. Chem. 1999, 64, 2994-
2995. (g) Evans, D. A.; Campos, K. R.; Tedrow, J . S.; Micheal, F. E.;
Gagne, M. R. J . Am. Chem. Soc. 2000, 122, 7905-7920.
(8) (a) Nakano, H.; Okuyama, Y.; Hongo, H. Tetrahedron. Lett. 2000,
41, 4615-4618. (b) Nakano, H.; Okuyama, Y.; Hongo, H. J . Org. Chem.
2001, 66, 620-625.
(9) (a) Uozumi, Y.; Tanahashi, A.; Lee, S. Y.; Hayashi, T. J . Org.
Chem, 1993, 58, 1945-1948. (b) Doucet, H.; Brown, J . M. Tetrahe-
dron: Asymmetry 1997, 9, 3775-3784.
(4) Ingo, S.; Helmchen, G. Tetrahedron Lett. 1998, 39, 261-264.
(5) (a) Maruoka, K.; Murase, N.; Yamamoto, H. J . Org. Chem. 1993,
58, 2938-2939. (b) Ishihara, K.; Yamamoto, H. J . Am. Chem. Soc.
1994, 116, 1561-1562. (c) Kobayashi, S.; Araki, M.; Hachiya, I. J . Org.
Chem. 1994, 59, 3758-3759. (d) Kobayashi, S.; Ishitani, H. J . Am.
Chem. Soc. 1994, 116, 4083-4084. (e) Ishihara, K.; Kurihara, H.;
Yamamoto, H. J . Am. Chem. Soc. 1996, 118, 3049-3050. (f) Kobayashi,
S.; Hachiya, I.; Ishitani, H.; Araki, M. Tetrahedron Lett. 1997, 38,
3193-3194.
(6) (a) Oi, S.; Kashiwagi, K.; Inoue, Y. Tetrahedron Lett. 1998, 39,
6253-6256. (b) Ghosh, A. K.; Matsuda, H. Org. Lett. 1999, 13, 2157-
2159.
10.1021/jo0201474 CCC: $22.00 © 2002 American Chemical Society
Published on Web 06/11/2002
J . Org. Chem. 2002, 67, 5011-5014
5011

SCHEME 1
SCHEME 3
SCHEME 2
TABLE 1. En a n tioselective Diels-Ald er Rea ction s of
Cyclop en ta d ien e w ith Dien op h iles 6a ,b
catalyst
temp
% eec
entry dienophile (mol %) (time, h) % yielda endo/exob (config)
1
6a
6a
6a
6a
6a
6a
6a
6a
6a
6a
6a
6a
6a
6b
12a (20) -45 °C(10) 82(7a )
12b(20) -45 °C(20) 95(7a )
91:9
89:11
89:11
93:7
91:9
93:7
92:8
96:4
96:4
96:4
94:6
91:9
92:8
75:25
36(2R)
37(2R)
69(2R)
85(2R)
81(2R)
25(2R)
16(2R)
87(2R)
90(2R)
90(2R)
88(2R)
93(2R)
93(2R)
86(2S)d)
82% isolated yield and endo selectivity (36% ee) (entry
1), whereas the use of the catalyst 12b (X ) ClO4) led to
almost complete conversion, but the endo adduct was
obtained in only 37% ee (entry 2). However, the reaction
by Pd(II)-POT catalyst 12c (X ) SbF6) gave the DA
adduct 7a in 90% isolated yield and endo enantioselec-
tivity (69% ee) (entry 3). Furthermore, the reaction at
the lower temperature of -78 °C afforded the endo adduct
7a in the higher enantiomeric excess (85% ee) (entry 4).
Even the use of 10 mol % of chiral complex 12c, the
reaction is no less effective than the use of 20 mol %
(entry 5). These results indicated that the SbF6 counte-
rion was more effective than OTf and ClO4. We also
tested the catalytic ability of 14 (M ) Pd, X ) SbF6)
derived from the isomeric ligand 5 of 1, but did not give
satisfactory results (77%, 25% ee) (entry 6). To test the
nature of the metal, we prepared the catalyst 12d (M )
Pt, X ) SbF6), but did not afford good results in the
chemical yield and enantioselectivity (30%, 16% ee) (entry
7). Continuously, we attempted to use the calatysts
12e-g (M ) Pd, X ) SbF6) that were derived from the
modified ligands 2-4 of 1. The DA reaction using chiral
ligand 12e under the similar reaction conditions to 12c
gave good results for both chemical yield and enantiose-
2
3
12c(20) -45 °C(1)
12c(20) -78 °C(4)
90(7a )
74(7a )
4
5
12c(10) -78 °C(32) 61(7a )
6
14(20)
-78 °C(3)
77(7a )
7
12d (20) -78 °C(24) 30(7a )
8
12e(10) -78 °C(15) 88(7a )
9
12f(5)
-78 °C(15) 70(7a )
10
11
12
13
14
12f(2.5) -78 °C(15) 50(7a )
12g(10) -78 °C(3)
12g(5) -78 °C(5)
93(7a )
92(7a )
12g(2.5) -78 °C(24) 80(7a )
12g(5) -78 °C(92) 61(7b)
a
b
Isolated yields. Endo/exo ratios were determined by HPLC
or 1H NMR. c ee of endo isomers were determined by chiral HPLC
using a Daicel OD-H column (6c: 0.5mL/min, hexane:2-propanol
d
) 9:1). After conversion to the corresponding iodolactone, the
absolute configuration was determined by comparison with known
optical rotation.3e
lectivity (88%, 87%ee) (entry 8). The DA reaction using
more conformationally constrained catalyst 12f than 12e
also proceeded in good enantioselectivity (90% ee) when
using 5 mol % and also 2.5 mol % (entry 9-10). Our
attempt using the most conformationally constrained
catalyst 12g (10, 5 and 2.5 mol %) proved to give fairly
good results (entry 11-13), in which gave the best results
for the chemical yield (92%) and enantioselectivity (93%
ee) when using 5 mol % of 12g, and importantly the less
molar use of 12g (2.5 mol %) also gave the same result
(93% ee). In addition, the DA reaction with fumaroyl-
(10) Narasaka, K.; Iwasawa, N.; Inoue, M.; Yamada, T.; Nakashima,
M.; Sugimori, J . J . Am. Chem. Soc. 1989, 111, 5340-5345.
5012 J . Org. Chem., Vol. 67, No. 14, 2002

SCHEME 4
Exp er im en ta l Section
Gen er a l P r oced u r e for th e Syn th esis of P h osp h in e Ox-
id es (10a -c). (1S)-(-)-10-mercaptoisoborneol (1.17 mmol), the
corresponding (2-formylphenyl)(diaryl)phosphine oxides 9a -c
(1.17 mmol), p-toluenesulfonic acid monohydrate (0.12 mmol),
and benzene (10 mL) were placed in a flask equipped with a
Dean-Stark trap. The mixture was refluxed for 6 h. The solvent
was evaporated under a reduced pressure, and the residue was
purified by column chromatography on silica gel (elution with
AcOEt: hexane ) 1:2) to afford 10a -c.
(1R,3R,5R,8S)-11,11-Dim eth yl-4-oxa -5-[2-d i(m-tolyl)ph os-
p h in yl]p h en yl-6-th ia tr icyclo[6.2.1.0]u n d eca n e (10a ): yield,
91% ; white solid; mp 70-74 °C. [R]23 ) -106.2 (c 2.1, CHCl3).
D
IR (KBr) cm-1: 1181, 751, 712, 697. 1H NMR (CDCl3) δ: 0.72-
0.82 (m, 1H), 0.88-0.99 (m, 4H), 1.34-1.53 (m, 4H), 1.59-1.68
(m, 2H), 1.77 (m, 1H), 1.89 (brs, 1H), 2.37 (d, J ) 0.7, 6H), 2.63
(d, J ) 14.2 Hz, 1H), 3.01 (d, J ) 14.4 Hz, 1H), 3.19 (m, 1H),
6.35 (s, 1H), 7.13-7.41 (m, 8H), 7.52-7.59 (m, 3H), 7.84 (m, 1H).
13C NMR (CDCl3) δ: 20.44, 21.41, 21.46, 23.38, 27.23, 30.00,
34.18, 37.79, 41.68, 45.52, 46.66, 80.82, 85.50, 127.80, 127.98,
128.12, 128.14, 128.31, 128.33, 129.11, 129.27, 129.43, 129.69,
132.51, 132.58, 132.63, 132.67, 132.72, 138.22, 138.43, 143.79,
143.90. HRMS m/z: Calcd for C31H35O2PS (M+): 502.2095. Found:
502.2051.
(1R,3R,5R,8S)-11,11-Dim et h yl-4-oxa -5-[2-d i(3,3-xylyl)-
p h osp h in yl]p h en yl-6-th ia tr icyclo[6.2.1.0]u n d eca n e (10b):
a
X-ray structure of 11a . Selected bond lengths and angles: Pd-
yield, 85% ; white solid; mp 67-70 °C. [R]23 ) -121.6 (c 1.6,
D
Cl1: 2.305(3), Pd-Cl2: 2.349(4), Pd-S: 2.257(3), Pd-P: 2.234(3)
Å, Cl1-Pd-Cl2: 91.9(1), Cl1-Pd-P: 89.1(1), Cl2-Pd-S: 85.5(1),
S-Pd-P: 93.7(1), Cl1-Pd-S: 176.0(1), Cl2-Pd-P: 175.4(2)°.
Short nonbonding distances of Cl atoms are drawn in the above
structure. 3.93 Å is the distance between the Cl atom and the
center of an equatorial phenyl ring.
CHCl3). IR (KBr) cm-1: 1180, 851, 754, 692. 1H NMR (CDCl3)
δ: 0.75 (m, 1H), 0.89-0.99 (m, 4H), 1.33-1.53 (m, 5H), 1.59-
1.64 (m, 2H), 1.78 (m, 1H), 2.31 (d, J ) 0.50, 12H), 2.63 (d, J )
14.2 Hz, 1H), 2.97 (d, J ) 14.2 Hz, 1H), 3.16 (m, 1H), 6.27 (s,
H), 7.17 (m, 2H), 7.22-7.30 (m, 6H), 7.55 (m, 1H), 7.83 (m, 1H).
13C NMR (CDCl3) δ: 20.45, 21.30, 21.32, 23.38, 27.25, 29.97,
34.18, 37.85, 41.63, 45.52, 46.65, 80.97, 85.46, 127.81, 127.99,
129.60, 129.65, 129.74, 129.79, 129.88, 132.33, 132.37, 133.40,
133.44, 133.51, 137.93, 137.95, 138.12, 138.14, 143.63, 143.74.
HRMS m/z: Calcd for C33H39O2PS (M+): 530.2408. Found:
530.2425.
1,3-oxazolidin-2-one 6b using the catalysts 12g also gave
good enantioselectivity (86% ee),3e although the moderate
chemical yield (61%).
To gain structural information about the palladium
species coordinated with the POT ligand, the crystal
structure of PdCl2-POT 11a was determined by X-ray
study. As shown in Scheme 4, the complex 11a has a
square-planar geometry, being coordinated with S and
P atoms of POT and one of the phenyl groups of PdCl2-
POT 11a is oriented axially and the other equatorially
with respect to the square-plane of the complex. In addi-
tion, there is also shown no space between the POT lig-
and and two Cl atoms since their nonbonding distances
approach the sum of van der Waals radii. Based on the
X-ray structure of 11a , a model of the enantioselective
reaction with dienophile 6a and Pd(II)-POT complex was
proposed (Scheme 4). It is thought that dienophile 6a is
L2-coordinated to the Pd(II)-POT complex via the two
carbonyl oxygen atoms affording the square-planar com-
plex in the intermediate A. Probably, intermediate B,
having a different orientation of the dienophile, may be
less favored to form due to the steric interaction of di-
methyl groups on the norbornane ring and the olefin part
on dienophile. Furthermore, the attack of diene at the
si-face of the acryloyl group of 6a is favored to afford the
observed (2R)-cycloadduct, since the attack at the re-face
would be hindered by the equatorial phenyl group of the
ligand.
(1R,3R,5R,8S)-11,11-Dim eth yl-4-oxa -5-[2-d i(1-n a p h th yl)-
p h osp h in yl]p h en yl-6-th ia tr icyclo[6.2.1.0]u n d eca n e (10c):
yield, 87%; white solid. mp 135-138 °C. [R]20 ) -89.9 (c 2.6,
D
CHCl3). IR (KBr) cm-1: 1179, 802, 775, 753. 1H NMR (CDCl3) δ:
0.71 (m, 1H), 0.83-0.98 (m, 4H), 1.25-1.36 (m, 2H), 1.42-1.45
(m, 3H), 1.62-1.91 (m, 3H), 2.57 (d, J ) 14.0, 1H), 2.95 (d, J )
13.9 Hz, 1H), 3.39 (brs, 1H), 6.75 (brs, 1H), 7.11-7.16 (m, 2H),
7.31-7.39 (m, 4H), 7.42-7.58 (m, 5H), 7.89-8.03 (m, 5H), 8.83
(d, J ) 8.08 Hz, 2H). 13C NMR (CDCl3) δ: 19.51, 20.37, 23.39,
27.11, 29.86, 33.92, 37.65, 41.69, 45.46, 46.67, 85.25, 124.04,
124.16, 124.26, 124.37, 126.44, 127.37, 127.92, 128.10, 128.19,
128.39, 128.64, 129.60, 129.74, 130.14, 132.51, 132.98, 133.12,
133.16, 133.47, 133.64, 133.83, 133.97, 134.09, 134.20. HRMS
m/z: Calcd for C37H35O2PS (M+): 574.2095. Found: 574.2087.
Gen er a l P r oced u r e for th e Syn th esis of P h osp h in oox-
a th ia n e Liga n d s (2-4). To a mixture of 10a -c (0.82 mmol)
and Et3N (10a ,b: 16.3 mmol, 10c: 24.6 mmol) in toluene (10a ,b:
20 mL, 10c: 2 mL) was added trichlorosilane (10a ,b: 8.16 mmol,
10c: 16.4 mmol) at 0 °C. The reaction mixture was stirred at
150 °C for 24 h. After being cooled to room temperature, the
reaction mixture was diluted with Et2O and quenched with small
amount of saturated NaHCO3. The resulting suspension was
filtered through Celite, and solid was washed with Et2O. The
combined organic layer was dried over anhydrous MgSO4 and
concentrated under a reduced pressure. The residue was purified
by column chromatography on silica gel (elution with AcOEt:
hexane ) 1:4) to afford 2-4.
(1R,3R,5R,8S)-11,11-Dim eth yl-4-oxa -5-[2-d i(m-tolyl)ph os-
p h in o]p h en yl-6-th ia tr icyclo[6.2.1.0]u n d eca n e (2): yield,
In conclusion, we have shown the first example using
S-P type, phosphinooxathiane ligand for enantioselective
DA reaction. The explored cationic Pd(II)-phosphinoox-
athiane complex 12g, obtained from the reactions of chi-
ral phosphinooxathiane ligand 4, PdCl2, and AgSbF6, was
an efficient chiral catalyst for the reaction. Further stud-
ies including modification to the dienes, dienophiles, lig-
ands design, and mechanistic investigation are in progress.
78% ; white solid. mp 38 °C. [R]24 ) -89.3 (c 2.2, CHCl3). IR
D
(KBr) cm-1: 777, 747, 696. 1H NMR (CDCl3) δ: 0.86-1.06 (m,
5H), 1.41-1.51 (m, 4H), 1.58-1.74 (m, 3H), 1.90 (m, 1H), 2.29
(s, 6H), 2.71 (d, J ) 14.2 Hz, 1H), 3.20 (d, J ) 14.4 Hz, 1H),
3.59 (m, 1H), 6.39 (d, J ) 7.8 Hz, 1H), 6.93 (m, 1H), 7.02-7.08
(m, 2H), 7.12-7.23 (m, 7H), 7.37 (m, 1H), 7.71 (m, 1H). 13C NMR
(CDCl3) δ: 20.47, 21.43, 21.46, 23.41, 27.28, 29.98, 34.32, 37.92,
41.85, 45.58, 46.77, 81.16, 85.63, 127.28, 127.35, 128.20, 128.30,
J . Org. Chem, Vol. 67, No. 14, 2002 5013

128.48, 129.30, 129.43, 129.49, 130.45, 130.70, 131.05, 133.88,
134.10, 134.42, 137.82, 137.93, 143.97, 144.31. HRMS m/z: Calcd
for C31H35OPS (M+): 486.2146. Found: 486.2063.
139.76, 139.94. Anal. Calcd for C31H35Cl2OPSPd: C, 56.08; H,
5.31. Found: C, 56.09; H, 5.30. MS m/z: 662 (M+).
Dich lor o[(1R,3R,5R,8S)-11,11-d im eth yl-4-oxa -5-[2-d i(3,3-
xylyl)p h osp h in o]p h en yl-6-th ia tr icyclo[6.2.1.0]u n d eca n e]-
p a lla d iu m (11d ): yield, 91%; yellow crystals. mp 209-210 °C.
(1R,3R,5R,8S)-11,11-Dim et h yl-4-oxa -5-[2-d i(3,3-xylyl)-
ph osph in o]ph en yl-6-th iatr icyclo[6.2.1.0]u n decan e (3): yield,
83% ; white solid. mp 38-42 °C. [R]23 ) -84.8 (c 2.1, CHCl3).
[R]20 ) -109.7 (c 2.2, CHCl3). IR (KBr) cm-1: 847, 732, 688. 1H
D
D
IR cm-1: 847, 747, 693. H NMR (CDCl3) δ: 0.86-1.06 (m, 5H),
1
NMR (CDCl3) δ: 0.89-1.09 (m, 5H), 1.30 (s, 3H), 1.71-1.83 (m,
4H), 2.11 (m, 1H), 2.32(d, J ) 16.0 Hz, 12H), 3.56 (m, 1H), 3.64
(d, J ) 14.2 Hz, 1H), 4.12 (d, J ) 14.2 Hz, 1H), 5.41 (s, 1H),
6.69 (m, 1H), 7.02 (d, J ) 13.7 Hz, 2H), 7.12 (s, 1H), 7.25 (s,
1H), 7.34 (t, J ) 7.7 Hz, 1H), 7.48 (d, J ) 13.4 Hz, 2H), 7.61 (t,
J ) 7.7 Hz, 1H), 7.89 (m, 1H). 13C NMR (CDCl3) δ: 20.19, 21.39,
21.45, 23.01, 27.10, 33.68, 37.40, 39.94, 45.49, 45.72, 47.13, 81.91,
86.46, 125.49, 125.62, 129.22, 129.35, 131.98, 132.08, 132.11,
133.64, 133.68, 133.81, 133.87, 134.85, 137.86, 138.05, 138.79,
138.91, 139.25, 139.43. HRMS m/z: Calcd for C33H39Cl2OPSPd
(M+): 690.0871. Found: 690.0944.
1.41-1.54 (m, 4H), 1.60-1.71 (m, 3H), 1.91 (m, 1H), 2.24 (s,
12H), 2.71 (d, J ) 14.4 Hz, 1H), 3.20 (d, J ) 14.4 Hz, 1H), 3.59
(m, 1H), 6.37 (d, J ) 7.75 Hz, 1H), 6.89-6.98 (m, 7H), 7.18 (m,
1H), 7.37 (m, 1H), 7.71 (m, 1H). 13C NMR (CDCl3) δ: 20.22,
21.43, 21.48, 23.04, 27.13, 30.93, 33.71, 37.43, 39.98, 45.52, 45.75,
47.17, 81.95, 86.50, 127.21, 127.29, 128.42, 129.41, 130.26,
130.40, 131.06, 131.35, 131.39, 131.67, 133.91, 137.62, 137.72,
143.95, 144.29. HRMS m/z: Calcd for C33H39OPS (M+): 514.2459.
Found: 514.2485.
(1R,3R,5R,8S)-11,11-Dim eth yl-4-oxa -5-[2-d i(1-n a p h th yl)-
ph osph in o]ph en yl-6-th iatr icyclo[6.2.1.0]u n decan e (4): yield,
Dich lor o[(1R,3R,5R,8S)-11,11-d im et h yl-4-oxa -5-[2-d i(1-
n a p h t h y l)p h o s p h i n o ]p h e n y l-6-t h i a t r i c y c lo [6.2.1.0]-
u n d eca n e]p a lla d iu m (11e): yield, 85%; yellow crystals. mp
65%; white solid. mp 71-74 °C. [R]24 ) -40.8 (c 1.3, CHCl3).
D
IR (KBr) cm-1: 798, 774, 746. H NMR (CDCl3) δ: 0.76-0.97(m,
1
204-208 °C. [R]22 ) -97.5 (c 2.4, CHCl3). IR (KBr) cm-1: 800,
D
5H), 1.33-1.46 (m, 4H), 1.54 (s, 1H), 1.65-1.68 (m, 2H), 1.81
(m, 1H), 2.67 (d, J )14.2 Hz, 1H), 3.08 (d, J ) 14.2 Hz, 1H),
3.53 (brs, 1H), 6.49 (d, J ) 7.42 Hz, 1H), 6.84 (m, 1H), 6.94-
7.11 (m, 3H), 7.28-7.51 (m, 7H), 7.75-7.89 (m, 5H), 8.40-8.51
(m, 2H). 13C NMR (CDCl3) δ: 20.44, 23.41, 27.20, 29.95, 34.16,
37.81, 41.86, 45.53, 46.75, 81.33, 85.58, 125.66, 125.68, 125.78,
125.92, 126.24, 126.37, 126.46, 126.76, 126.85, 127.46, 127.53,
128.56, 128.59, 128.71, 129.47, 129.51, 129.82, 133.12, 133.17,
133.42, 133.43, 133.49, 134.63, 135.51, 144.06, 144.42. HRMS
m/z: Calcd for C37H35OPS (M+): 558.2146. Found: 558.2196.
Gen er a l P r oced u r e for P r ep a r a tion of P d Cl2- a n d
P tCl2-P h osp h in ooxa th ia n e Com p lexes (11a -e, 13). PdCl2
(0.035 mmol) or PtCl2 (0.035 mmol) and phosphinooxathianes
1-5 (0.035 mmol) were suspended in 1,2-dichloroethane (2 mL)
under Ar. The mixture was refluxed for 6h and the resulting
yellow solution was cooled and filtered. The filtrate was con-
densed under a reduced pressure and the residue was recrystal-
lized from hexane: CH2Cl2 to afford 11a -e and 13.
1
772, 746. H NMR (CDCl3) δ: 0.83-1.06 (m, 5H), 1.25-1.47 (m,
3H), 1.58-1.78 (m, 4H), 1.99 (d, J ) 13.4 Hz, 1H), 3.22 (m, 1H),
3.64 (d, J ) 14.0 Hz, 1H), 4.18 (d, J ) 14.0 Hz, 1H), 5.08 (s,
1H), 7.18-8.18 (m, 15H), 8.25 (d, J ) 8.4 Hz, 1H), 8.69 (d, J )
7.8 Hz, 1H), 10.01 (dd, J ) 6.9 Hz, 20.0 Hz, 1H). 13C NMR
(CDCl3) δ: 20.22, 22.99, 27.05, 33.94, 37.22, 40.38, 45.46, 45.84,
47.13, 82.09, 86.92, 124.41, 124.60, 124.52, 125.79, 125.90,
125.95, 126.80, 127.53, 127.62, 128.81, 128.94, 129.06, 129.36,
129.81, 130.89, 132.13, 132.46, 133.28, 133.62, 133.75, 134.25,
134.34, 134.91, 135.38, 138.75, 143.64.
Dich lor o[(1R,3S,5S,8S)-11,11-dim eth yl-4-oxa-5-(2-diph en -
ylphosphino)phenyl-6-thiatricyclo[6.2.1.0]undecane]palladium
(13): yield, 91%; yellow crystals. mp 204-207 °C. [R]20 ) 74.8
D
(c 2.5, CHCl3). IR (KBr) cm-1: 769, 750, 694. 1H NMR (CDCl3)
δ: 0.95 (d, J ) 13.4 Hz, 6H), 1.24 (m, 1H), 1.38 (m, 1H), 1.54 (m,
1H), 1.81-1.82 (m, 2H), 2.21-2.43 (m, 2H), 3.68-3.79 (m, 2H),
3.93 (d, J ) 12.7 Hz, 1H), 5.66 (s, 1H), 6.68 (m, 1H), 7.35-7.57
(m, 8H), 7.63-7.70 (m, 2H), 7.90-8.05 (m, 3H). 13C NMR (CDCl3)
δ: 18.62, 19.52, 24.83, 27.95, 33.94, 44.27, 45.31, 46.21, 48.73,
84.32, 85.75, 124.99, 125.95, 126.83, 128.44, 128.63, 129.54,
129.72, 129.81, 131.83, 132.58, 132.94, 133.65, 134.30, 134.46,
Dich lor o[(1R,3R,5R,8S)-11,11-dim eth yl-4-oxa-5-(2-diph en -
ylph osph in o)ph en yl-6-th iatr icyclo[6.2.1.0]u n decan e]palladi-
u m (11a ): yield, 95%; yellow crystals. mp 238-241 °C. [R]23
)
D
-159.2 (c 2.5, CHCl3). IR (KBr) cm-1: 747, 710, 692. 1H NMR
(CDCl3) δ: 0.88-1.09 (m, 5H), 1.29 (s, 3H), 1.59-1.83 (m, 4H),
2.12 (m, 1H), 3.53 (m, 1H), 3.64 (d, J ) 14.4, 1H), 4.13 (d, J )
14.2, 1H), 5.40 (s, 1H), 6.70 (m, 1H), 7.32-7.64 (m, 10H), 7.93
(m, 3H). 13C NMR (CDCl3) δ: 20.17, 22.99, 27.07, 33.65, 37.33,
40.02, 45.45, 45.73,47.11, 82.01, 86.59, 125.84, 125.97, 128.40,
128.59, 129.53, 129.62, 129.79, 131.79, 131.83, 132.43, 132.46,
132.95, 133.00, 134.34, 134.50, 134.80, 134.97, 139.02. Anal.
Calcd for C29H31Cl2OPSPd: C, 54.77; H, 4.91. Found: C, 54.65;
H, 4.89. MS m/z: 634 (M+).
134.92, 135.09, 138.63, 138.75. HRMS m/z: Calcd for C29H31
-
Cl2OPSPd: 634.0245. Found: 634.0153.
Gen er a l P r oced u r e for En a n tioselective P d (II) a n d P t-
(II)-Ca ta lyzed Diels-Ald er Rea ction s. PdCl2-POT com-
plexes 11a , 11c-e, 13 (1 equiv) or PtCl2-POT complex 11b (1
equiv) and appropriate silver salt (2 equiv) in CH2Cl2 (1 mL)
were stirred at room temperature under Ar for 1 h. The catalyst
complex was then cooled to the temperature as shown in Table
1, and acryloyl-1,3-oxazolidin-2-one 6a (50 mg, 0.36 mmol) or
fumaroyl-1,3-oxazolidin-2-one 6b (77 mg, 0.36 mmol) in CH2Cl2
(1 mL) followed by cyclopentadiene (117 mg, 1.77 mmol) was
added. The reaction mixture was stirred for the specified amount
of time and quenched with sat. aq NaHCO3. The mixture was
extracted with CHCl3, and the organic layer was washed with
brine and dried over MgSO4. Evaporation of the solvent under
a reduced pressure afforded a crude residue that was purified
by column chromatograpy on silica gel (elution with AcOEt:
hexane ) 1:4) to give the cycloadducts 7a ,b. The ee of 7a was
determined by HPLC (Chiralcel OD-H, 1.0 mL/min, hexane:2-
propanol ) 90:10). The ee of 7b was determined by comparison
of the known optical rotation of iodolactonization product derived
from 7b.3e
Dich lor o[(1R,3R,5R,8S)-11,11-dim eth yl-4-oxa-5-(2-diph en -
ylph osph in o)ph en yl-6-th iatr icyclo[6.2.1.0]u n decan e]platin -
u m (11b): yield, 90%; colorless crystals. mp 211-214 °C. [R]23
D
) -122.4 (c 2.0, CHCl3). IR (KBr) cm-1: 748, 713, 696. 1H NMR
(CDCl3) δ: 0.86-1.09 (m, 5H), 1.29 (s, 3H), 1.62-1.82 (m, 4H),
2.13 (m, 1H), 3.57-3.62 (m, 2H), 4.11 (d, J ) 14.0, 1H), 5.45 (s,
1H), 6.62-6.70 (m, 1H), 7.32-7.65 (m, 10H), 7.81-7.94 (m, 3H).
13C NMR (CDCl3) δ: 20.24, 22.91, 27.11, 33.51, 37.36, 39.99,
45.49, 45.86, 47.13, 81.29, 86.61, 125.62, 125.74, 128.23, 128.41,
129.19, 129.33, 129.49, 131.73, 131.77, 132.17, 132.20, 132.60,
132.64, 134.46, 134.49, 134.61, 134.66, 138.44. HRMS m/z: Calcd
for C29H31Cl2OPSPt: 723.0858. Found: 723.0629.
Dich lor o[(1R,3R,5R,8S)-11,11-d im eth yl-4-oxa -5-[2-d i(m -
tolyl)p h osp h in o]p h en yl-6-th ia tr icyclo[6.2.1.0]u n d eca n e]-
X-r a y Cr ysta l Str u ctu r e of P d Cl2-P OT (11a ). X-ray
crystallographic data of PdCl2-POT (11a ) have been deposited
at the Cambridge Crystallographic Data Center (CCDC 186659)
in CIF format.
p a lla d iu m (11c): yield, 95%; yellow crystals. mp 203-205 °C.
1
[R]20 ) -127.1 (c 2.2, CHCl3). IR (KBr) cm-1: 780, 706,691. H
D
NMR (CDCl3) δ: 0.89-1.09(m, 5H), 1.29 (s, 3H), 1.61-1.83 (m,
4H), 2.11 (m, 1H), 2.38(d, J ) 19.5 Hz, 6H), 3.54 (m, 1H), 3.65
(d, J ) 14.4 Hz, 1H), 4.13 (d, J ) 14.4 Hz, 1H), 5.42 (s, 1H),
6.69 (m, 1H), 7.17 (m, 1H), 7.29-7.47 (m, 6H), 7.50-7.65 (m,
2H), 7.85-7.92 (m, 2H). 13C NMR (CDCl3) δ: 20.22, 21.55, 21.63,
23.04, 27.12, 33.70, 37.40, 40.01, 45.50, 45.76, 47.16, 82.00, 86.56,
125.68, 125.81, 129.26, 129.44, 132.27, 132.31, 132.67, 133.77,
133.83, 133.85, 133.89, 134.88, 138.21, 138.40, 138.86, 138.99,
Su p p or tin g In for m a tion Ava ila ble: Experimental in-
formation including structural data for compounds 9a -c, and
1H and 13C NMR spectra data of compounds 2-4, 9a -c, 10a -
c, 11a -e, and 13. This material is available free of charge
via the Internet at http://pubs.acs.org.
J O0201474
5014 J . Org. Chem., Vol. 67, No. 14, 2002