A practical method for the large-scale synthesis of diastereomerically pure (2R,5S)-3-phenyl-2-(8-quinolinoxy)-1,3-diaza-2-phosphabicyclo-[3.3.0]- octane Ligand (QUIPHOS). Synthesis and X-ray structure of its corresponding chiral π-allyl palladium complex

Full text of DOI:10.1021/jo990205u

8
940
J . Org. Chem. 1999, 64, 8940-8942
A P r a ctica l Meth od for th e La r ge-Sca le
Syn th esis of Dia ster eom er ica lly P u r e
2R,5S)- 3-P h en yl-2-(8-qu in olin oxy)-
,3-d ia za -2-p h osp h a bicyclo-[3.3.0]-octa n e
Liga n d (QUIP HOS). Syn th esis a n d X-r a y
Str u ctu r e of Its Cor r esp on d in g Ch ir a l
π-Allyl P a lla d iu m Com p lex
chiral P-pyridine and quinoline phosphine ligands and
their successful use in asymmetric palladium-catalyzed
allylic substitution reactions leading to enantiomeric
excesses (ee) up to 96%.9 Thus, one of these (ligand 7)
has particularly focused our attention as a result of its
easy access and its stability to air and moisture. This
P,N ligand presents a chiral diazaphospholidine ring
and a quinoloxy group bound to a stereogenic phos-
phorus atom; we propose the acronym QUIPHOS for 7.
Herein, we report an efficient, highly optimized procedure
for the preparation of this ligand involving only three
steps from commercial inexpensive precursors and the
X-ray structure of its corresponding chiral π-allyl pal-
ladium complex 8 to prove unequivocally the stereochem-
istry of the P(III) atom and the ability of QUIPHOS to
serve as a bidentate P, N ligand and to describe the sense
of asymmetric induction observed in Pd(0) allylic substi-
tution.
(
,10
1
J ean Michel Brunel, Thierry Constantieux, and
G e´ rard Buono*
E.N.S.S.P.I.C.A.M., UMR 6516 CNRS,
Facult e´ de St J e´ r oˆ me, Av. Escadrille Normandie Niemen,
1
3397 Marseille, Cedex 20, France
Received February 3, 1999
(Revised Manuscript Received May 28, 1999)
The use of catalytic asymmetric reactions for the
The first key step deals with the synthesis of chiral
synthesis of highly enantiomerically enriched chiral
compounds is of growing importance in organic chemistry
(S)-5-oxopyrrolidine-2-carboxanilide 2 from (L)-glutamic
acid 1 and aniline according to a modified reported
procedure.11 This step has been improved on a large-scale
synthesis (0.4 mol) using a Dean-Stark apparatus to
eliminate the water produced during the reaction, in-
creasing the chemical yield from 46% to 85% (69 g) after
crystallization in methanol. The second significant im-
provement affecting the ligand synthesis was tied to the
reduction of the previously mentioned diamide 2. This
reduction was conducted on a 0.35 mol scale. The
hydrolysis step was controlled using the minimum re-
quired amount of 30% KOH solution (i.e., 4 equiv of water
1
and in the chemical industry at large. In this area, the
practical utility of a catalytic asymmetric method is
closely tied to the accessibility of the catalyst and can be
severely undermined if the process for preparation of the
catalyst proves too costly or technically difficult for large-
scale production. Over the past 30 years, a wide variety
of organophosphorus ligands have been described and
2
successfully used in various asymmetric reactions. Nev-
ertheless, few of these ligands have found industrial
3
applications; the most famous of them are DIOP, BI-
4
5
6
NAP, DIPAMP, or DuPHOS. In the past few years, the
use of phosphine oxazoline ligands in palladium asym-
with respect to 1 equiv of LiAlH
4
), leading after distilla-
tion of the crude product to a chemical yield up to 92%
7
metric reactions has attracted great interest. However,
(57 g). Thus, this two-step sequence provides pure chiral
the preparation of stable chiral ligands possessing a
stereogenic phosphorus center via a large-scale synthesis
(
S)-2-anilinomethyl pyrrolidine 3 in a total 78% yield with
1
2
respect to L-glutamic acid (Scheme 1).
8
has appeared to be difficult to envision. Recently, we
The synthesis of ligand 7 was accomplished under
argon by exchange reaction in refluxing toluene between
tris(dimethylamino)phosphine 4 (9.25 g, 56.8 mmol) and
(S)-3 (10 g, 56.8 mmol) for 2 h followed by addition of
have described the straightforward synthesis of new
(1) (a) Ojima, I. Catalytic Asymmetric Synthesis; VCH Publishers:
New York, 1993. (b) Noyori, R. Asymmetric Catalysis in Organic
Synthesis; J ohn Wiley: New York, 1993. (c) Nugent, W. A.; RajanBabu,
T. V.; Burk, M. J . Science 1993, 259, 479. (d) Dawson, G. J .; Bower, J .
F.; Williams, J . M. J . Contemp. Org. Synth. 1996, 3, 277. (e) Tonks,
L.; Williams, J . M. J . Contemp. Org. Synth. 1997, 4, 353.
8
-hydoxyquinoline (8.23 g, 56.8 mmol). The reflux was
maintained for 2 h, and crystallization overnight in
toluene afforded diastereoselectively pure ligand 7 as a
white solid stable to air and moisture in 98% yield (19.5
g) (Scheme 2).13
(
2) (a) Brunner, H.; Zeittlmeir, W. Handbook of Enantioselective
Catalysis, Vol. Products and Catalysts and Vol, II Ligands-
I
References; VCH: Weinheim, 1993. (b) Kagan, H. B.; Sasaki, M. The
Chemistry of Organophosphorus Compounds; Hartley, F. R., Ed.; J ohn
Wiley and Sons: New York, 1990; pp 51-102.
The synthesis of complex 8 was achieved by mixing an
equimolar amount of bis(µ-chloro)bis(π-allyl)dipalladium
(
3) Kagan, H. B.; Dang, T. P. J . Am. Chem. Soc. 1972, 94, 6429.
(4) Miyashita, A.; Yasuda, A.; Takaya, H.; Totiumi, K.; Ito, T.;
Souchi, T.; Noyori, R. J . Am. Chem. Soc. 1980, 102, 7932.
5) Knowles, W. S.; Sabacky, M. J .; Vineyard, B. D.; Weinkauff, D.
J . J . Am. Chem. Soc. 1975, 97, 2567.
(
(9) (a) Brunel, J . M.; Constantieux, T.; Labande, A.; Lubatti, F.;
Buono, G. Tetrahedron Lett. 1997, 38, 5971. (b) Constantieux, T.;
Brunel, J . M.; Labande, A.; Buono, G. Synlett 1998, 49. (c) Muchow,
G.; Brunel, J . M.; Maffei, M.; Pardigon, O.; Buono, G. Tetrahedron
1998, 54, 10435.
(
6) Burk, M. J . J . Am. Chem. Soc. 1991, 113, 8518.
(7) (a) von Matt, P.; Pfaltz, A. Angew. Chem., Int. Ed. Engl. 1993,
3
2, 566. (b) Sprinz, J .; Helmchen, G. Tetrahedron 1993, 34, 1769. (c)
(10) It is noteworthy that compound 7 has been successfully used
as ligand in an enantioselective copper-catalyzed Diels-Alder reaction
of 3-acryloyl-1,3-oxazolidine-2-one with cyclopentadiene, leading to
enantioselectivities up to 99%. Brunel, J . M.; Del Campo, B.; Buono,
G. Tetrahedron Lett. 1998, 39, 9663.
Asymmetry 1995, 2535. (g) Togni, A.; Venanzi, L. M. Angew. Chem.,
Int. Ed. Engl. 1994, 33, 497. (h) Trost, B. M.; van Vranken, D. L. Chem.
Rev. 1996, 96, 395. (i) Williams, J . M. J . Synlett 1996, 705.
(11) (a) Iriiuchijima, S. Synthesis 1978, 684. (b) Schmidt, U.; Sch o¨ lm,
R. Synthesis 1978, 752.
(12) Optical purity of 3 has been verified by 31P NMR spectroscopy
using (-)-dichloromenthyloxyphosphinite as chiral derivatizing agent.
Thus, only one diastereomer was detected, indicating that no racem-
ization about the stereogenic center occurred during the synthesis. For
the method used, see: Brunel, J . M.; Faure, B. Tetrahedron: Asymmetry
1995, 6, 2353.
(8) Although myriad examples of phosphines possessing carbon-
centered chirality have been synthesized and applied in asymmetric
catalysis, few P-chiral ligands have been investigated because of their
inaccessibility. For a recent review, see: Petrusiewicz, K. M.; Zablocka,
M. Chem. Rev. 1994, 94, 1375.
1
0.1021/jo990205u CCC: $18.00 © 1999 American Chemical Society
Published on Web 11/06/1999

Notes
J . Org. Chem., Vol. 64, No. 24, 1999 8941
Sch em e 1
Sch em e 2
F igu r e 1. Structure of 8, showing labeling scheme. Selected
bond distances (Å): Pd1-P2, 2.216(2); Pd1-N7, 2.125(6); Pd1-
C28, 2.05(1); Pd1-C29, 2.230(9); Pd1-C30, 2.09(2); P2-O4,
1
.648(4); N7-C25, 1.32(2); N7-C14, 1.384(8); P2-N6, 1.62-
Sch em e 3
(5); P2-N5, 1.686(5); C17-O4, 1.393(8); C29-C30, 1.17(3);
C30-C28, 1.20(3). Selected bond angles (deg): P2-Pd1-N7,
9
1.3(2); P2-Pd1-C28, 101.5(3); P2-Pd1-C29, 164.7(3); P2-
Pd1-C30, 134.6(6); N7-Pd1-C28, 167.0(3); N7-Pd1-C29,
02.6(3); N7-Pd1-C30, 133.9(6); C28-Pd1-C29, 65.0(4);
C28-Pd1-C30, 33.8(7); C29-Pd1-C30, 31.3(6); Pd1-P2-O4,
03.4(2); Pd1-P2-N5, 123.7(2); Pd1-P2-N6, 124.8(2); O4-
1
1
P2-N5, 99.6(3); O4-P2-N6, 107.3(3); N5-P2-N6, 94.8(3);
C29-C28-C30, 13.6(7); Pd1-C30-C328, 71.6(8); Pd1-C29-
C30, 81.2(8).
4
and ligand 7 in methanol, followed by addition of LiClO .
This mixture was stirred for 1 h, and water was added
to afford a yellow precipitate. Crystallization from pe-
Sch em e 4
3
troleum ether/CHCl afforded the expected palladium
complex 8 in 92% yield as pale yellow crystals stable to
air and moisture (Scheme 3).14 X-ray diffraction analysis
led unambiguously to the determination of the proposed
structure for 7 with R absolute configuration at the
phosphorus (III) atom (Figure 1).15 In comparison, com-
plex 8 clearly demonstrates the bidentate chelating
ability of ligand 7 toward Pd metal through, respectively,
phosphorus and nitrogen atoms of the quinoline ring
displaying the expected longer distance (Pd(1)-C(29) )
2.230(9) Å) as compared to its partner trans to nitrogen
(Pd(1)-C(28) ) 2.05(1) Å). This is an expression of the
1
6
(
distance Pd(1)-P(2) ) 2.22 and Pd(1)-N(7) ) 2.13 Å).
higher trans influence of the phosphine ligand. The
plane of the allyl ligand is tilted 29.4° from the perpen-
dicular to the plane Pd-N-P. The sums of angles around
The Pd-C bond lengths are significantly different from
one another, the carbon atom trans to phosphorus
5 6
N and N atoms (respectively 351.4° and 346.8°) showed
in both cases a nonplanar configuration. Furthermore,
the observed torsion angle C9-N5-C8-C11 of 13.8°
suggests a reduced electronic interaction by decreasing
the overlap of the nitrogen lone pair orbital with the
π-aromatic system. The efficiency of this ligand in asym-
metric palladium-catalyzed reactions (Scheme 4) could
result from the unique conformation adopted by the
allylic system as a result of the steric hindrance of the
pyrrolidine ring. Thus, the asymmetric induction ob-
served could be apprehended from the transition state
(
13) The synthesis of the (2S,5R) enantiomer of ligand 7 may be
envisionned according to the same experimental procedure using
commercially available D-glutamic acid. For application of L- and
D-glutamic acid in asymmetric synthesis, see: Coppola, G. M.; Shuster,
H. F. Asymmetric Synthesis; Wiley-Interscience: New York, 1987; p
2
16.
14) Ligand 7 is not prone to oxidation, and a sample has been stored
(
for 1 year at room temperature in air without any alteration of the
product.
(
15) X-ray structure of palladium complex 8. A pale yellow crystal
3
(
0.4 × 0.3 × 0.2 mm ) grown from petroleum ether and chloroform by
a diffusion method was used for data collection. C23 Pd ‚ClO
) 561.85; orthorhombic; space group P2 ; a ) 8.918(1), b )
5.531(1), c ) 17.569(1) Å; R ) 90.000(1)°, â ) 90.000(1)°, γ ) 90.000-
H
2 2
1 1 1
26
O
5
N
3
P
1
1
4
;
M
1
(
r
1
1 in which the nucleophilic attack may occur predomi-
3
-3
1)°; V ) 2433.4(6) Å ; dcalcd ) 1.250 g cm . All of the measurements
nantly at the alkyl terminus trans to the better p-
acceptor (P . N) (Scheme 5).
In conclusion, we have reported a practical procedure
for the large-scale synthesis (up to 0.5 mol) of an efficient
chiral quinoline diazaphospholidine ligand 7 (QUIPHOS),
as well as the first X-ray structure of the corresponding
were made on a Rigaku diffractometer with Mo KR radiation. Cell
constants and the orientation matrix for data collection were obtained
from a least-squares refinement using setting angles of 30 reflections
in the range θ ) 1-25° for Z ) 4. A total of 2695 reflections were
collected at T ) 298 K and R ) 0.052 for the refined structure. The
standards were measured after every 120 reflections. Among the first
2
00 pairs of reflections, the signs of the corresponding calculated
differences established that the molecule is described with the correct
absolute configuration R at the phosphorus atom. Moreover, it has been
verified that crystallization does not occur to provide individual crystals
of different stereoisomers of complex 8.
(16) For a review, see: Appleton, T. G.; Clark, H. C.; Manzer, L. E.
Coord. Chem. Rev. 1973, 10, 335-422.

8
942 J . Org. Chem., Vol. 64, No. 24, 1999
Notes
Sch em e 5
(2R ,5S )-3-P h e n yl-2-(8-q u in olin oxy)-1,3-d ia za -2-p h os-
p h a bicyclo[3.3.0]octa n e (7) (QUIP HOS). To a 250 mL two-
necked round-bottomed flask containing 100 mL of dry toluene
were added under argon tris(dimethylamino)phosphine (4) (9.25
g, 56.8 mmol) and (S)-2-anilinomethyl pyrrolidine (3) (10.0 g,
5
6.8 mmol). The solution was heated to reflux, and the reaction
3
1
was monitored by P NMR spectroscopy. After 2 h and cooling
to room temperature, 8-hydroxyquinoline (8.23 g, 56.8 mmol)
was introduced under argon. The solution was then heated to
reflux, and this temperature maintained for 2 h. After comple-
tion of the reaction, the solution was allowed to rise to room
temperature overnight. White needles stable to air and moisture
were obtained after crystallization affording 16.3 g of the
expected ligand. Evaporation of the solvent and a second
crystallization of the crude residue in toluene led to another 3.2
chiral π-allyl palladium complex 8. Further studies to use
ligand 7 in various catalytic asymmetric reactions are
currently under investigation.
2
0
g of ligand 7, 98% yield (19.5 g): mp 135 °C; [R] -45.6 (c 1.0,
1
CH
6
1
2
Cl
2
); H NMR (400 MHz, CDCl
3
) δ 1.54 (dq, 1H, J ) 11.5,
.7 Hz), 1.84 (dtt, 2H, J ) 7.3, 7.3, 6.5 Hz), 1.93 (dq, 1H, J )
1.5, 6.5 Hz), 3.28 (ddd, 1H, J ) 8.7, 6.5 Hz, J P-H ) 5.9 Hz),
Exp er im en ta l Section
3.45 (ddd, 1H, J ) 10.2, 7.3 Hz, J P-H ) 7.3 Hz), 3.78 (dd, 1H, J
)
1
8.7, 6.5 Hz), 3.83 (m, 1H), 3.90 (q, 1H, J ) 6.5 Hz), 6.86 (t,
Ma ter ia ls a n d Meth od s. H, 13C, and 31P NMR spectra were
1
H, J ) 7.3 Hz), 7.13 (d, 2H, J ) 7.8 Hz), 7.18 (d, 1H, J ) 7.5
recorded on Bruker AC100, AC200, and AC400 spectrometers.
Hz), 7.22 (dd, 2H, J ) 7.8, 7.3 Hz), 7.35 (dd, 1H, J ) 8.3, 4.1
The chemical shifts (ppm) were determined relative to Me
4
Si
Hz), 7.37 (t, 1H, J ) 7.5 Hz), 7.46 (d, 1H, J ) 7.5 Hz), 8.12 (dd,
1
13
31
(
H and C) and 85% H
3
PO
4
( P). IR spectra were recorded on
13
1
(
J
1
1
H, J ) 8.3, 1.6 Hz), 8.89 (dd, 1H, J ) 4.1, 1.6 Hz); C NMR
a Perkin-Elmer 1720X FT-IR spectrometer. Toluene and tet-
rahydrofuran (THF) were distilled from sodium/benzophenone
ketyl immediately prior to use.
3
100.33 MHz, CDCl ) δ 26.6 (d, J P-C ) 5.0 Hz), 32.0, 48.0 (d,
P-C ) 33.2 Hz), 53.7, 65.6 (d, J P-C ) 9.1 Hz), 115.5 (d, J P-C )
4.1 Hz), 119.1, 119.6, 121.2, 121.9, 126.9, 129.1, 129.7, 135.8,
(
S)-5-Oxop yr r olid in e-2-ca r boxa n ilid e (2). In a 500 mL
31
42.2, 145.7 (d, J P-C ) 15.1 Hz), 148.9, 151.8; P NMR (40.5
MHz, CDCl ) δ 128.6. Anal. Calcd for C20H N OP: C, 72.07; H,
3 20 3
round-bottomed flask fitted with a Dean-Stark apparatus, a
mixture of L-glutamic acid (60 g, 0.4 mol) and aniline (350 mL)
was stirred at 195-200 °C. After 30 min, the mixture became
clear, and the water formed was removed by azeotropic distil-
lation. Stirring was maintained for 4 h. Excess of aniline was
then recovered at 60-70 °C under reduced pressure distillation.
The hot oily residue was swirled with acetone (250 mL) to lead
to the formation of a brown solid, which was collected by
filtration and dissolved in hot methanol (200 mL). The solution
was slowly cooled to room temperature to afford crystalline
optically pure (S)-5-oxopyrrolidine-2-carboxanilide as white
0
9
.6.00; N, 12.61; P, 9.30. Found: C, 72.0; H, 5.93; N, 12.44; P,
.40.
4
P d (7)(π-a llyl)]ClO (8). A mixture of bis(µ-chloro)bis(π-
[
allyl)dipalladium (558 mg, 1.52 mmol) and ligand 7 (1.10 g, 3.06
mmol) was placed in anhydrous MeOH (30 mL) under argon in
a 50 mL two-necked round-bottomed flask. The solution was
stirred at room temperature, and the solids almost dissolved
after 1 h, giving an orange solution. After small amount of
insoluble solids was filtered off, LiClO
4
2
‚3H O (1.62 g, 15.3 mmol)
in 6 mL of methanol was added, and the mixture was kept
stirring at room temperature for 2 h. Water (100 mL) was added
until no more yellow precipitates were formed. [Pd(7)(π-allyl)]-
2
0
needles in 85% yield (69 g): mp 189.0 °C; [R]
D
+18.0 (c 1.0,
) δ 2.00 (tdd, 1H, J ) 9.7,-
2.3, 4.3 Hz), 2.18 (td, 2H, J ) 9.7, 14.4 Hz), 2.31 (tdd, 1H, J )
.7, 12.3, 8.5 Hz), 4.19 (dd, 1H, J ) 8.5, 4.3 Hz), 7.06 (t, 1H, J
7.5 Hz), 7.32 (t, 2H, J ) 7.5 Hz), 7.63 (d, 2H, J ) 7.5 Hz),
.92 (s, 1H, D O exchangeable), 10.06 (s, 1H, D O exchangeable);
C NMR (25.18 MHz, DMSO-d ) δ 25.3, 29.3, 56.4, 119.3, 123.5,
28.8, 138.8, 171.3, 177.5. Anal. Calcd for C11 : C, 64.70;
1
MeOH); H NMR (400 MHz, DMSO-d
6
1
9
ClO
in vacuo. For a single-crystal X-ray analysis, the product was
recrystallized from petroleum ether/CHCl giving 8 as pale
yellow crystals in 92% yield: mp 142 °C; H NMR (400 MHz,
CDCl ) δ 1.88 (dq, J ) 11.5, 6.7 Hz, 1H, H18a), 1.94 (dtt, J ) 7.3,
.3, 6.5 Hz, 2H, H24), 2.15 (dq, J ) 11.5, 6.5 Hz, 1H, H18b), 2.74
br s, 1H, H28a), 2.93 (ddd, J ) 10.2, 7.3 Hz, J P-H ) 7.3 Hz, 1H,
19a), 3.13 (d, J ) 11.8 Hz, 1H, H28b), 3.61 (dd, J ) 8.7, 6.5 Hz,
4
(8) was obtained by filtration, washed with water, and dried
)
3
7
2
2
1
1
3
6
3
1
12 2 2
H N O
7
(
H
H, 5.88; N, 13.72. Found: C, 64.85; H, 5.74; N, 13.46.
(
S)-2-An ilin om eth yl P yr r olid in e (3). In a 1 L glass reactor
under argon fitted with a condenser and mechanical stirrer was
slowly added in dry THF (500 mL) at -10 °C 40.0 g of lithium
aluminum hydride (1.05 mol). This suspension was allowed to
rise to 0 °C and (S)-5-oxopyrrolidine-2-carboxanilide (71.4 g, 0.35
mol) was slowly added in portions to maintain a gentle bubbling.
After stirring overnight at room temperature, the suspension
was heated for 1 h under reflux. After the mixture cooled to 0
1
4
6
5
7
H, H9a), 3.80 (m, 1H, H19b), 4.02 (dd, J ) 8.7, 6.5 Hz, 1H, H9b),
.28 (dd, J ) 12.5 Hz, J P-H ) 14.4 Hz, 1H, H29a), 4.47 (q, J )
.5 Hz, 1H, H21), 5.00 (dd, J ) 7.6 Hz, J P-H ) 7.3 Hz, 1H, H29b),
.81 (tt, J ) 12.5, 7.6 Hz, 1H, H30), 6.98 (t, J ) 7.3 Hz, 1H, H13),
.08 (d, J ) 7.9 Hz, 2H, H16, H12), 7.28 (dd, J ) 7.9, 7.3 Hz, 2H,
H
H
10, H16), 7.34 (d, J ) 7.5 Hz, 1H, H20), 7.65 (t, J ) 7.5 Hz, 1H,
26), 7.74 (dd, J ) 8.3, 4.1 Hz, 1H, H23), 7.82 (d, J ) 7.5 Hz, 1H,
27), 8.56 (d, J ) 8.3 Hz, 1H, H15), 9.58 (d, J ) 4.1 Hz, 1H, H25);
°
C, the excess of lithium aluminum hydride was decomposed by
H
careful addition of 30% KOH solution (75 mL). This solution was
then stirred overnight at room temperature. The inorganic salts
13
C NMR (100.33 MHz, CDCl ) δ 26.7 (d, J P-C ) 4.0 Hz, C24),
3
3
(
)
1
1.1 (s, C18), 48.9 (d, J P-C ) 22.0 Hz, C19), 49.5 (br s, C28), 54.5
s, C ), 61.7 (s, C21), 87.7 (d, J P-C ) 38.1 Hz, C29), 116.9 (d, J P-C
8.1 Hz, C11, C12), 122.4 (s, C16), 122.8 (s, C26), 123.8 (s, C23),
were filtered off and washed with CH
solvents were removed under vaccuum, and the oily residuewas
2
Cl
2
(2 × 50 mL). The
9
purified by distillation to afford the desired (S)-2-anilinomethyl
24.7 (d, J P-C ) 10.0 Hz, C30), 125.8 (s, C20), 128.3 (s, C26), 129.4
2
0
pyrrolidine in 92% yield (56.6 g): bp 92.0 °C (0.1 mmHg); [R]
D
(s, C10, C13), 131.2 (s, C22), 136.0 (s, C15), 141.4 (s, C14), 141.7 (d;
1
+
19.2 (c 1.0, MeOH); H NMR (400 MHz, CDCl
3
) δ 1.43 (tdd,
31
J
P-C ) 12.0 Hz, C
MHz, CDCl ) δ 128.05. Anal. Calcd for C23
6.30; H, 4.19; N, 7.04; Cl, 5.95; P, 5.20; Pd, 17.85. Found: C,
6.82; H, 4.17; N, 7.40; Cl, 6.02; P, 5.18; Pd, 18.1.
8
), 145.9 (s, C25), 162.3 (s, C17); P NMR (40.5
1
1
1
H, J ) 8.9, 12.3, 6.7 Hz), 1.72 (m, 3H), 1.89 (dddd, 1H, J )
2.3, 8.9, 6.7, 5.3 Hz), 2.91 (td, 2H, J ) 6.5, 1.9 Hz), 2.94 (br dd,
H, J ) 11.9, 7.7 Hz), 3.15 (br dd, 1H, J ) 11.9, 4.5 Hz), 3.35
3
25 3 5
H N O
ClPPd: C,
4
4
(dddd, 1H, J ) 7.7, 6.7, 5.3, 4.5 Hz), 4.10 (br s, 1H), 6.62 (dd,
2
2
2
H, J ) 8.6, 1.0 Hz,), 6.62 (tt, 1H, J ) 7.3, 1.0 Hz), 7.16 (ddt,
H, J ) 8.6, 7.3, 2.1 Hz); 13C NMR (25.18 MHz, CDCl
) δ 25.7,
9.5, 46.5, 48.6, 57.6, 112.9, 117.2, 129.1, 148.5. Anal. Calcd for
: C, 74.00; H, 9.09; N, 15.90. Found: C, 75.08; H, 9.12;
Ack n ow led gm en t. We thank Dr. Michel Giorgi and
Pr. M. Pierrot for their kind assistance with X-ray
analysis of complex 8.
3
11 16 2
C H N
N, 15.81.
J O990205U