Synthesis of Chiral Rhenium Complexes Containing Functionalized Thiolate Ligands

Article abstract of DOI:10.1002/(SICI)1099-0682(199812)1998:12<2055::AID-EJIC2055>3.0.CO;2-2

Chiral racemic rhenium thiolate complexes [CpRe-(NO)(PPh₃)(SR)] were obtained under either acidic or basic conditions. Thus, when [CpRe(NO)(PPh₃)(CH₃)] (1) was treated with etheral HBF₄ and HSR the thiolate complexes [CpRe(NO)(PPh₃)(SR)] [SR = SCH₂(2-furyl) (2), SCH₂C-(O)OEt (3)] were obtained after chromatographic workup. Ligand exchange reactions between [CpRe(NO)(PPh₃)-(OC₄H₈)]BF₄ (4) and sodium thiolates yielded analogous complexes with SR = SH (5), SCH₂CH₂Ph (6), SCH₂CH=CH₂ (7). SR groups which tolerate strongly alkaline conditions may be introduced by treatment of 4 with HSR in the presence of sodium ethoxide as demonstrated by the highyield synthesis of 2 as well as of complexes with SR = SCH₂CH₂NHAc (8), SCH₂CH₂C(O)OH (9). A milder synthesis using hydrated sodium carbonate as a base provided 8 and compounds with SR = SCH₂CH₂C(O)OMe (10), SCH₂CH₂C(O)NHCH₂Ph (11) in high yields. Using similar methods, thiolate complexes of (R)-N-acetylcysteine (13), its methyl ester (14), (R)-N-phthaloylcysteine (16), and N-[(S)-3-mercapto-2-methylpropionyl]-S-proline (Captopril) (17) were obtained as diastereomeric pairs. The formation of 13 was preceded by the O-bonded isomer 12 which slowly rearranges in solution. 13 can be converted under acidic conditions into its methyl (14) or ethyl (15) esters. The diastereomers of 16 were separated by crystallization, and the structure of the (R,R)-isomer 16a determined.

Full text of DOI:10.1002/(SICI)1099-0682(199812)1998:12<2055::AID-EJIC2055>3.0.CO;2-2

FULL PAPER
Enantioselective Organic Syntheses Using Chiral Transition Metal Complexes, 7[᭛]
Synthesis of Chiral Rhenium Complexes Containing Functionalized Thiolate
Ligands
Nicolai Burzlaff and Wolfdieter A. Schenk*
Institut für Anorganische Chemie der Universität,
Am Hubland, D-97074 Würzburg, Germany
Fax: (internat.) ϩ 49(0)931/888-4605
E-mail: wolfdieter.schenk@mail.uni-wuerzburg.de
Received July 21, 1998
Keywords: N-Acetylcysteine / Amino acids / Captopril / Rhenium / S ligands
Chiral racemic rhenium thiolate complexes [CpRe-
(NO)(PPh3)(SR)] were obtained under either acidic or basic
conditions. Thus, when [CpRe(NO)(PPh3)(CH3)] (1) was
treated with etheral HBF4 and HSR the thiolate complexes
SCH2CH2NHAc (8), SCH2CH2C(O)OH (9).
synthesis using hydrated sodium carbonate as
A
milder
base
a
provided 8 and compounds with SR = SCH2CH2C(O)OMe
(10), SCH2CH2C(O)NHCH2Ph (11) in high yields. Using
similar methods, thiolate complexes of (R)-N-acetylcysteine
(13), its methyl ester (14), (R)-N-phthaloylcysteine (16), and
N-[(S)-3-mercapto-2-methylpropionyl]-S-proline (Captopril)
(17) were obtained as diastereomeric pairs. The formation of
13 was preceded by the O-bonded isomer 12 which slowly
rearranges in solution. 13 can be converted under acidic
conditions into its methyl (14) or ethyl (15) esters. The
diastereomers of 16 were separated by crystallization, and
the structure of the (R,R)-isomer 16a determined.
[CpRe(NO)(PPh3)(SR)] [SR
= SCH2(2-furyl) (2), SCH2C-
(O)OEt (3)] were obtained after chromatographic workup.
Ligand exchange reactions between [CpRe(NO)(PPh3)-
(OC4H8)]BF4 (4) and sodium thiolates yielded analogous
complexes with SR = SH (5), SCH2CH2Ph (6), SCH2CH=CH2
(7). SR groups which tolerate strongly alkaline conditions
may be introduced by treatment of 4 with HSR in the
presence of sodium ethoxide as demonstrated by the high-
yield synthesis of 2 as well as of complexes with SR =
Thiolate ligands have some remarkable properties which conditions. Treatment of the racemic methylrhenium com-
are exploited by nature in a number of important metallo- plex 1[13] with a twofold excess of etheral HBF4 and 2-(mer-
enzymes.[2] SR groups being soft donors bind strongly to captomethyl)furan or ethyl mercaptoacetate followed by
most of the transition metal ions. Due to their high polariz- chromatography over silica gave the corresponding rhenium
ability and π-donor capacity,[3] they are able to stabilize thiolate complexes 2 and 3 in fair to good yields (Eq. 1).
various oxidation states of the metal and to promote the
formation of clusters[2][4] which can function as electron
reservoirs for redox processes. Enzymatic reactions which
lead to the transformation of coordinated thiolate ligands
seem to be comparatively rare. One of the few prominent
examples is the penicillin biosynthesis[5] whose first step in-
volves the oxidative dehydrogenation of an iron-coordi-
nated, cysteine-containing tripeptide to a thioaldehyde in-
termediate.[6] We have recently described a similar oxidative
route for the synthesis of stable thioaldehyde complexes of
ruthenium[7][8] and rhenium.[9] In order to further exploit
the characteristic reactivity of coordinated thioaldehydes in
nucleophilic additions and cycloadditions[8][10][11][12] we de-
cided to investigate thiolate complexes bearing various
functional groups on the SR ligand.
Since the strongly acidic conditions of this route may not
be compatible with a number of functional groups, a syn-
thesis based on a nucleophilic substitution at rhenium was
sought. The tetrahydrofuran complex [CpRe(NO)(P-
Ph3)(OC4H8)]BF4 (4) which is easily obtained through acid
cleavage of 1[14] seemed to be an appropriate starting mate-
rial. Although 4 was noted to be labile[14] it has found only
sporadic use in ligand exchange reactions.[15] When 4 was
treated with isolated sodium thiolates in THF/ethanol, the
corresponding thiolate complexes 5–7 were formed in good
Results
Achiral Thiolates
Two synthetic strategies were chosen in which the rhe-
nium–sulfur bond is formed under either acidic[8] or basic
[᭛]
Part 6: Ref.[1]
.
Eur. J. Inorg. Chem. 1998, 2055Ϫ2061
WILEY-VCH Verlag GmbH, D-69451 Weinheim, 1998
1434Ϫ1948/98/1212Ϫ2055 $ 17.50ϩ.50/0
2055

N. Burzlaff, W. A. Schenk
FULL PAPER
Chiral, Enantiomerically Pure Thiolates
yields (Eq. 2). The thiolate anions may also be generated in
situ from thiol and sodium ethoxide. This was demon-
strated by the high-yield synthesis of 2, 8, and 9 (Eq. 3).
Reaction of the THF complex 4 with (R)-N-acetylcyst-
eine and sodium ethoxide initially gave the orange-brown
carboxylate complex 12a, b as a 1:1 mixture of diastereoiso-
mers. Upon prolonged storage in solution or refluxing in
acetone, 12a, b converts almost quantitatively into the yel-
low S-bonded isomer 13a, b (Eq. 5) which, after one crystal-
lization, was obtained in 17% de. Conversely, solutions of
13a, b revert back to an equilibrium mixture containing ap-
proximately 5% 12a, b.
The use of ethoxide as a base may, however, cause prob-
lems when chiral thiolates are to be employed which would
racemize under strongly alkaline conditions. Hydrated so-
dium carbonate, which finds some use in peptide synth-
eses,[16] was expected to be mild enough to circumvent this
obstacle. Indeed, simple stirring of a mixture of 4,
Na2CO3 • 10 H2O, and a thiol produced the expected thiol-
ate complexes 8, 10, and 11 in high purity and yield (Eq. 4).
For a further elaboration of the thiolate side chain it may
be desirable to have the carboxylate group protected as es-
The new thiolate complexes are yellow, slightly air-sensi- ter. To this end, the diastereomeric complexes 13a, b were
tive crystalline solids which are more or less readily soluble treated with alcohol and acid (Eq. 6). This reaction was
in all common organic solvents. Typical spectroscopic fea- also intended to be an additional test of the stability of the
tures include low NO stretching frequencies in the infrared rhenium complex. The expected esters 14a, b and 15a, b
spectra which hint at the high donor ability of the SR li- were indeed obtained, albeit in less than satisfactory yields.
gand. In the 1H NMR spectra, all methylene protons of the Spectroscopic analysis of the crude reaction mixtures indi-
SR group are diastereotopic; those in α position give widely cated that the losses were primarily due to the chromatog-
separated signals which are easily analyzed. The SH com- raphic workup which was necessary to remove the acid,
plex 5 exhibits a high-field signal at δ ϭ 0.09 which is split rather than destruction of the rhenium complex. Obviously
into a doublet due to coupling with phosphorus. In the 13C- it is advisable to convert amino acids to their esters before
NMR spectra the α carbon signal is shifted by approxi- coordinating them to the transition metal. Thus, 4 was re-
mately 15 ppm to lower field compared to the uncoordi- acted with the methyl esters of (R)-N-acetylcysteine, (R)-N-
nated thiol, and split into a doublet due to coupling with phthaloylcysteine, and N-[(S)-3-mercapto-2-methylpropi-
phosphorus. In cases of doubt such as 7–11 this serves as onyl]-S-proline in the presence of sodium carbonate (Eq.
unambiguous proof that the SR ligand is indeed coordi- 7). The three products were isolated as 1:1 mixtures of dia-
nated through the sulfur atom.
stereoisomers. 17a, b was partially enriched by crystalliza-
2056
Eur. J. Inorg. Chem. 1998, 2055Ϫ2061

Enantioselective Organic Syntheses Using Chiral Transition Metal Complexes, 7
FULL PAPER
tion to 15% de while diastereomerically pure 16a crys- Figure 1. Molecular structure (R,R)-[CpRe(NO)(PPh3)(SCH2CH-
(NC8H4O2)COOMe)] (16a) (without H atoms)[a]
tallized from an acetone solution.
The physical properties of the diastereomeric thiolate [a] Selected distances [pm] and angles[°] (standard deviations in pa-
rentheses): Re(1)–S(1) 239.45(10), Re(1)–P(1) 235.44(12), Re(1)–
complexes 13a,b–17a,b closely resemble those of the other
N(1) 176.3(4), N(1)–O(1) 119.7(5), S(1)–C(1) 182.2(5), S(1)–Re(1)–
members of this series. As expected, they give double sets
P(1) 87.31(6), S(1)–Re(1)–N(1) 102.35(11), P(1)–Re(1)–N(1)
1
of signals in their H-, 13C-, and 31P-NMR spectra. Coordi-
92.80(13),
167.4(2).
Re(1)–S(1)–C(1) 106.2(2),
P(1)–Re(1)–S(1)–C(1)
nation to rhenium via the sulfur atom is unequivocally in-
ferred from the large coupling of the α carbon with the
phosphorus atom. This clearly distinguishes 13a, b from
their carboxylate-bound isomers 12a, b whose 13C-NMR
spectra exhibit doublet resonances for the carboxylate car-
bon atom.
conditions were developed in order to ensure tolerance for
a range of functional groups. Acid cleavage of the methyl
complex 1 produces the solvent-stabilized 16-electron spe-
cies [CpRe(NO)(PPh3)]ϩ which immediately picks up any
stronger Lewis base present in the solution.[19] The thiol
complexes [CpRe(NO)(PPh3)(HSR)]BF4 thus formed elim-
inate HBF4 simply upon chromatography over silica.[9] This
route produces thiolate complexes in good yields but is lim-
ited of course to SR groups which tolerate strongly acidic
conditions.
Crystal and Molecular Structure of 16a
From an acetone solution of 16a, b diastereomerically
pure 16a was obtained by slow crystallization. A suitable
single crystal was analyzed by X-ray diffraction. It belonged
to the enantiomorphic space group P21 which immediately
showed that it is an enantiomerically pure compound. The
stereocenters at both rhenium and carbon have the (R) con-
figuration (Figure 1) which is in line with the Flack param-
eter. Bond distances and angles are well within the normal
range for complexes of the type [CpRe(NO)(PPh3)-
(SR)].[17][18]
The angle S–Re–N(1) [102.35(11)°] is surprisingly large
for both 16a and the (diarylmethyl)thiolate complex investi-
gated by Gladysz.[18] As there are not any obvious steric
interactions between the NO and SR ligands, the driving
force of this distortion must be electronic in origin.[1] Also
of note is the transoid arrangement of the groups at rhe-
nium and sulfur [dihedral angle P–Re–S–C(1) ϭ 167.4ο]
which simultaneously minimizes steric interactions as well
as the repulsion between the lone pairs at sulfur and the
HOMO of the [CpRe(NO)(PPh3)] complex fragment.[1]
Gladysz et al., in their seminal work on chiral rhenium
complexes,[20] made extensive use of the dichloromethane
[21]
complex [CpRe(NO)(PPh3)(ClCH2Cl)]BF4
in ligand ex-
change reactions. With the strongly nucleophilic thiolate
ions this compound, in addition to ligand exchange, un-
dergoes nucleophilic substitution at carbon which leads to
the formation of (chloromethyl)thioether complexes in size-
able quantities.[9] The tetrahydrofuran complex 4 whose
synthesis[14] can easily be scaled up to multigram quantities,
finally proved to be the starting material of choice.
For potentially ambidentate ligands such as allyl thiolate
or the anions of cysteine and its derivatives, coordination
through sulfur is favored thermodynamically. Nevertheless,
for cysteine itself, which under the conditions of equation
5 exists in solution in its doubly deprotonated form, the
carboxylate isomer is formed as the kinetic product. A simi-
lar observation was not made in the case of the 3-mercapto-
propionic acid complex 9 (Eq. 3), due probably to the ab-
sence of bulky groups around the sulfur atom. Bond forma-
tion between the chiral rhenium complex and the various
SR ligands was not expected to be accompanied by kinetic
Discussion
This work was aimed at the synthesis of chiral racemic resolution. Nevertheless it is gratifying that partial or even
rhenium thiolate complexes [CpRe(NO)(PPh3)(SR)]. Three full diastereomer separation could easily be effected by sim-
routes proceeding under acidic, basic, or close to neutral ple crystallization.
Eur. J. Inorg. Chem. 1998, 2055Ϫ2061
2057

N. Burzlaff, W. A. Schenk
FULL PAPER
Conclusions
2J(H,H) ϭ 12.1 Hz, 2 H; SCH2], 4.07, 4.12 [AB system of quartets,
3
2J(H,H) ϭ 10.8 Hz, J(H,H) ϭ 7.1 Hz, 2 H; OCH2], 5.35 (s, 5 H;
C5H5). – 13C NMR (100 MHz, [D6]acetone, 20 °C): δ ϭ 14.5 (s;
CH3), 43.6 [d, 3J(P,C) ϭ 9 Hz; SCH2], 60.6 (s; OCH2), 92.6 (s;
C5H5), 174.0 (s; CO). – 31P NMR (162 MHz, [D6]acetone, 20 °C):
δ ϭ 19.5 (s). – IR (CH2Cl2) ν˜ ϭ 1721 (CO), 1653 cm–1 (NO). –
C27H27NO3PReS (662.8) calcd C 48.93, H 4.11, N 2.11, S 4.84;
found C 48.91, H 4.01, N 1.97, S 5.08.
It has been shown here that the chiral Lewis acid
[CpRe(NO)(PPh3)]ϩ can be efficiently connected to simple
thiolates as well as those derived from biologically relevant
molecules such as the amino acid (R)-cysteine or N-[(S)-3-
mercapto-2-methylpropionyl]-S-proline, an ACE (angio-
tensin converting enzyme) inhibitor which under the brand
name “Captopril” is used as an antihypertension drug.
Apart from the more classical use of the rhenium complex
fragment as a protective group for the thiolate function and
a chiral auxiliary[20] for stereoselective addition reactions,
one can also envisage that compounds such as 13–17 might
find uses as specific “organometallic markers” in biochem-
istry[22] or as carriers of heavy atoms for protein crystal-
lography.[23]
[ CpRe( NO) ( PPh3) ( SH) ] (5): A solution of 4 (281 mg, 0.40
mmol) and NaSH (28 mg, 0.50 mmol) in THF (20 ml) and ethanol
(20 ml) was stirred 1 h at 20 °C. The mixture was taken to dryness,
and the residue dissolved in benzene and filtered over Celite. The
filtrate was partially evaporated and the product precipitated by
adding pentane. Yield 178 mg (77%), m.p. 60 °C (dec). – 1H NMR
(400 MHz, C6D6, 20 °C): δ ϭ 0.09 [d, 3J(P,H) ϭ 12.6 Hz, 1 H;
SH], 4.77 (s, 5 H; C5H5). – 13C NMR (100 MHz, C6D6, 20 °C):
δ ϭ 91.4 (s; C5H5). – 31P NMR (162 MHz, C6D6, 20 °C): δ ϭ 23.0
(s). – IR (CH2Cl2): ν˜ ϭ 1655 cm–1 (NO). – C23H21NOPReS (567.7)
calcd C 47.91, H 3.67, N 2.43, S 5.56; found C 47.91, H 3.75, N
2.25, S 5.41.
This work has been supported by the Deutsche Forschungsge-
meinschaft (SFB 344 “Selektive Reaktionen Metall-aktivierter Mo-
leküle”).
[ CpRe( NO) ( PPh3) ( SCH2CH2Ph) ] (6): This compound was
prepared analogously from 4 and sodium 2-phenylethanethiolate.
Yield 237 mg (87%), m.p. 168 °C. – 1H NMR (400 MHz, C6D6, 20
°C): δ ϭ 2.88–3.34 (m, 4 H; CH2CH2), 4.80 (s, 5 H; C5H5). – 13C
NMR (100 MHz, C6D6, 20 °C): δ ϭ 42.1 (s; CH2), 45.1 [d,
3J(P,C) ϭ 8 Hz; SCH2], 91.1 (s; C5H5). – 31P NMR (162 MHz,
C6D6, 20 °C): δ ϭ 20.2 (s). – IR (CH2Cl2): ν˜ ϭ 1644 cm–1 (NO). –
C31H29NOPReS (680.8) calcd C 54.69, H 4.29, N 2.06, S 4.71;
found C 54.39, H 4.30, N 2.05, S 4.66.
Experimental Section
All experiments were carried out in Schlenk tubes under an
atmosphere of nitrogen using suitably purified solvents. – IR: Per-
kin-Elmer 283, Bruker IFS 25. – 1H NMR: Bruker AMX 400, δ
values relative to TMS. – 13C NMR: Bruker AMX 400, δ values
relative to TMS; assignments were routinely checked by DEPT; in
some cases the 13C-NMR signals of quarternary carbon atoms
were too weak to be detected. – 31P NMR: Bruker AMX 400, δ
values relative to 85% H3PO4. The 1H- and 13C-NMR signals of
the PPh3 ligand are very similar for all compounds and have there-
fore been omitted from the lists of spectral data. – Elemental analy-
ses: Analytical Laboratory of the Institut für Anorganische
Chemie. The following starting materials were obtained as de-
scribed in the literature: [CpRe(NO)(PPh3)(CH3)] (1),[13] [CpRe(N-
O)(PPh3)(OC4H8)]BF4 (4),[14] NaSH,[24] other sodium thiolates,[25]
HSCH2CH2C(O)NHCH2Ph,[26] (R)-N-phthaloylcysteine.[16] All
other reagents were used as purchased.
[ CpRe( NO) ( PPh3) ( SCH2CHϭCH2) ] (7): This compound was
prepared analogously from 4 and sodium allylthiolate. Yield 210
mg (85%), m.p. 202 °C. – 1H NMR (400 MHz, CDCl3, 20 °C): δ ϭ
2
3
3.02, 3.39 [AB system of doublets, J(H,H) ϭ 13.0 Hz, J(H,H) ϭ
2
3
7.2 Hz, 2 H; SCH2], 4.87 [ddd, J(H,H) ϭ 2.0 Hz, J(H,H) ϭ 9.9
Hz, J(H,H) ϭ 1.0 Hz, 1 H; ϭCH2], 4.95 [dd, J(H,H) ϭ 1.9 Hz,
3J(H,H) ϭ 16.9 Hz, 1 H; ϭCH2], (s, 5 H; C5H5), 5.87 [ddt,
3J(H,H) ϭ 16.9 Hz, J(H,H) ϭ 9.8 Hz, J(H,H) ϭ 7.2 Hz, 1 H; ϭ
CH] . – 13C NMR (100 MHz, CDCl3, 20 °C): δ ϭ 45.3 [d, 3J(P,C) ϭ
7 Hz; SCH2], 91.3 (s; C5H5), 113.2 (s; ϭCH2), 141.2 (s; ϭCH). –
31P NMR (162 MHz, CDCl3, 20 °C): δ ϭ 19.0 (s). – IR (CH2Cl2):
ν˜ ϭ 1645 (NO), 1608 cm–1 (CϭC). – C26H25NOPReS (616.7) calcd
C 50.64, H 4.09, N 2.27, S 5.20; found C 50.99, H 4.31, N 2.20,
S 4.50.
4
2
3
3
[ CpRe( NO) ( PPh3) ( SCH2C4H3O) ] (2): To a solution of 1 (225
mg, 0.40 mmol) and 2-(mercaptomethyl)furan (115 mg, 1.00 mmol)
in toluene (15 ml) was added at –70 °C a solution of HBF4 in
diethyl ether (1.00 mmol). The mixture was allowed to warm up to
20 °C, and all volatiles were removed under vacuum. The semi-
solid residue was chromatographed with THF/ether over a short
silica column and further purified by crystallization from dichloro-
methane/pentane. Yield 137 mg (52%), m.p. 153 °C. – 1H NMR
(400 MHz, [D6]acetone, 20 °C): δ ϭ 3.73, 3.77 [AB system,
2J(H,H) ϭ 14.2 Hz, 2 H; SCH2], 5.28 (s, 5 H; C5H5), 6.13 [dd,
3J(H,H) ϭ 3.2 Hz, 4J(H,H) ϭ 0.8 Hz, 1 H; CH], 6.28 [dd,
3J(H,H) ϭ 3.1 Hz, 3J(H,H) ϭ 1.9 Hz, 1 H; CH], 7.36 [dd,
[ CpRe( NO) ( PPh3) ( SCH2C4H3O) ] (2): To a solution of 4 (281
mg, 0.40 mmol) and 2-(mercaptomethyl)furan (57 mg, 0.50 mmol)
in THF (20 ml) and ethanol (20 ml) was added at 20 °C a solution
of sodium ethoxide in ethanol (0.50 mmol). After 1 h the mixture
was taken to dryness, and the residue dissolved in benzene and
filtered over Celite. The filtrate was partially evaporated and the
product precipitated by adding pentane. Yield 257 mg (94%).
4
3J(H,H) ϭ 1.8 Hz, J(H,H) ϭ 0.9 Hz, 1 H; CH]. – 13C NMR (100
[ CpRe( NO) ( PPh3) ( SCH2CH2NHAc) ] (8): This compound
was prepared analogously from 4 and N-acetylcysteamine. Yield
MHz, [D6]acetone, 20 °C): δ ϭ 39.4 [d, 3J(P,C) ϭ 9 Hz; SCH2],
92.3 (s; C5H5), 106.2 (s; CH), 111.1 (s; CH), 141.2 (s; CH), 158.9
(s; CH). – 31P NMR (162 MHz, [D6]acetone, 20 °C): δ ϭ 19.6 (s). –
1
209 mg (79%), m.p. 154 °C. – H NMR (400 MHz, C6D6, 20 °C):
δ ϭ 1.71 (s, 3 H; CH3), 2.48 (m, 1 H; CH2), 2.96 (m, 1 H; CH2),
3.37 (m, 1 H; SCH2), 3.95 (m, 1 H; SCH2), 4.87 (s, 5 H; C5H5),
5.77 (s, br, 1 H; NH). – 13C NMR (100 MHz, C6D6, 20 °C): δ ϭ
IR (CH2Cl2): ν˜
28H25NO2PReS (656.8) calcd C 51.21, H 3.84, N 2.13, S 4.88;
found C 50.90, H 3.88, N 1.98, S 5.16.
ϭ
1654 (NO), 1606 cm–1 (CϭC).
–
C
3
23.2 (s; CH3), 40.3 [d, J(P,C) ϭ 8 Hz; SCH2], 43.3 (s; CH2), 91.5
[ CpRe( NO) ( PPh3) ( SCH2C( O) OEt) ] (3): This compound was
prepared analogously from 1 and ethyl mercaptoacetate. Yield 149
mg (94%), m.p. 106 °C. – 1H NMR (400 MHz, [D6]acetone, 20 °C):
(s; C5H5), 168.9 (s; CO). – 31P NMR (162 MHz, C6D6, 20 °C): δ ϭ
20.2 (s). – IR (CH2Cl2): ν˜ ϭ 1650 (NO), 1513 cm–1 (CONH). –
C27H28N2O2PReS (661.8) calcd C 49.00, H 4.26, N 2.23, S 4.85;
found C 49.14, H 4.51, N 3.98, S 4.65.
3
δ ϭ 1.24 [t, J(H,H) ϭ 7.1 Hz, 3 H; CH3], 3.07, 3.45 [AB system,
2058
Eur. J. Inorg. Chem. 1998, 2055Ϫ2061

Enantioselective Organic Syntheses Using Chiral Transition Metal Complexes, 7
FULL PAPER
[ CpRe( NO) ( PPh3) ( SCH2CH2COOH) ] (9): This compound
was prepared analogously from 4 and 3-mercaptopropionic acid.
Yield 239 mg (92%), m.p. 205 °C (dec). – 1H NMR (400 MHz,
C6D6, 20 °C): δ ϭ 2.56 (m, 1 H; CH2), 2.27–2.89 (m, 2 H; CH2),
3.09 (m, 1 H; CH2), 4.77 (s, 5 H; C5H5). – 13C NMR (100 MHz,
dichloromethane/pentane. Yield 50 mg (25%), dec. 163 °C. – Both
diastereoisomers 1H NMR (400 MHz, CDCl3, 20 °C): δ ϭ 1.98 (s,
3 H; CH3), 2.02 (s, 3 H; CH3), 2.67 [dd, 2J(H,H) ϭ 13.6 Hz,
3J(H,H) ϭ 3.6 Hz, 1 H; SCH2], 2.86 [dd, 2J(H,H) ϭ 13.2 Hz,
3J(H,H) ϭ 6.0 Hz, 1 H; SCH2], 3.21–3.27 (m, 2 H; SCH2), 3.67 (s,
3 H; OCH3), 3.76 (s, 3 H; OCH3), 4.58–4.64 (m; 2 ϫ 1 H; CH),
3
C6D6, 20 °C): δ ϭ 37.5 [d, J(P,C) ϭ 8 Hz; SCH2], 39.6 (s; CH2),
91.2 (s; C5H5), 177.8 (s; CO). – 31P NMR (162 MHz, C6D6, 20 °C): 5.19 (s, 5 H; C5H5), 5.22 (s, 5 H; C5H5), 6.44 [d, 3J(H,H) ϭ 7.2 Hz,
δ ϭ 19.5 (s). – IR (CH2Cl2): ν˜ ϭ 1742 (COOH), 1661 cm–1 (NO). – 1 H; NH], 6.74 [d, J(H,H) ϭ 5.6 Hz, 1 H; NH]. – 13C NMR (100
3
C26H25NO3PReS (648.7) calcd C 48.14, H 3.88, N 2.16, S 4.94; MHz, CDCl3, 20 °C): δ ϭ 23.0 (s; CH3), 23.2 (s; CH3), 42.0 [d,
found C 48.23, H 3.95, N 2.01, S 4.77.
3J(P,C) ϭ 8 Hz ; SCH2], 45.0 [d, 3J(P,C) ϭ 8 Hz; SCH2], 52.1 (s;
OCH3), 52.3 (s; OCH3), 54.7 (s; CH), 55.3 (s; CH), 91.5 [d,
2J(P,C) ϭ 1 Hz; C5H5], 91.6 (s; C5H5), 169.8, 170.1, 172.1, 172.2
(s; HNCO and COOMe). – 31P NMR (162 MHz, CDCl3, 20 °C):
δ ϭ 18.6 (s), 18.7 (s). – IR (CH2Cl2): ν˜ ϭ 1748 (COOMe), 1651
cm–1 (NO). – C29H30N2O4PReS (719.8) calcd C 48.39, H 4.20, N
3.89, S 4.45; found C 48.32, H 4.12, N 3.75, S 4.32.
[ CpRe( NO) ( PPh3) ( OCOCH( NHAc) CH2SH) ] (12a, b): This
compound was prepared analogously from 4 and (R)-N-acetylcyst-
eine. Yield 237 mg (84%), orange-brown crystalline solid, dec. 57
1
°C. – Both diastereoisomers: H NMR (400 MHz, [D6]acetone, 20
3
3
°C): δ ϭ 1.33 [t, J(H,H) ϭ 8.5 Hz, 1 H; SH], 1.40 [dd, J(H,H) ϭ
3
9.0 Hz, J(H,H) ϭ 7.8 Hz, 1 H; SH], 1.78 (s, 3 H; CH3), 1.84 (s, 3
H; CH3), 2.39, 2.56 [AB system of dd, 2J(H,H) ϭ 13.3 Hz,
3J(H,H) ϭ 8.9 Hz, 3J(H,H) ϭ 8.3 Hz, 3J(H,H) ϭ 4.8 Hz,
3J(H,H) ϭ 4.0 Hz, 2 H; SCH2], 2.39, 2.66 [AB system of dd,
2J(H,H) ϭ 13.3 Hz, 3J(H,H) ϭ 8.9 Hz, 3J(H,H) ϭ 7.2 Hz,
3J(H,H) ϭ 4.8 Hz, 3J(H,H) ϭ 4.2 Hz, 2 H; SCH2], 4.10 [dt,
3J(H,H) ϭ 6.4 Hz, 3J(H,H) ϭ 4.3 Hz, 1 H; CH], 4.18 [dt,
[ CpRe( NO) ( PPh3) ( SCH2CH( NHAc) COOEt) ] (15a, b): This
compound was prepared analogously by refluxing a solution of
13a, b (200 mg, 0.28 mmol) in ethanol (10 ml) in the presence of
HBF4. Yield 49 mg (24%), 19% de (by NMR), dec. 197 °C. – Major
diastereoisomer: 1H NMR (400 MHz, [D6]acetone, 20 °C): δ ϭ
3
1.24 [t, J(H,H) ϭ 7.1 Hz, 3 H; CH3], 1.92 (s, 3 H; CH3), 2.75 [dd,
3
3J(H,H) ϭ 6.6 Hz, J(H,H) ϭ 4.5 Hz, 1 H; CH], 5.40 (s, 2 ϫ 5 H;
3
2J(H,H) ϭ 13.3 Hz, J(H,H) ϭ 6.9 Hz, 1 H; SCH2], 2.99–3.06 (m,
C5H5), 6.62 [d, 3J(H,H) ϭ 6.1 Hz, 1 H; NH], 6.69 [d, 3J(H,H) ϭ
5.7 Hz, 1 H; NH]. – 13C NMR (100 MHz, [D6]acetone, 20 °C): δ ϭ
22.9 (s; CH3), 23.0 (s; CH3), 27.8 (s; SCH2), 27.9 (s; SCH2), 55.1
1 H; SCH2), 4.15 [q, 3J(H,H) ϭ 7.2 Hz, 2 H; OCH2], 4.53 [dt,
3J(H,H) ϭ 7.6 Hz, 3J(H,H) ϭ 6.6 Hz, 1 H; CH], 5.35 (s, 5 H;
C5H5), 7.01 [d, 3J(H,H) ϭ 7.0 Hz, 1 H; NH]. – 13C NMR (100
MHz, CDCl3, 20 °C): δ ϭ 14.2 (s; CH3), 23.2 (s; CH3), 45.2 [d,
3J(P,C) ϭ 8 Hz ; SCH2], 55.0 (s; CH), 61.3 (s; OCH2), 91.6 (s;
C5H5), 169.9, 170.7 (s; HNCO and COOEt). – 31P NMR (162
MHz, [D6]acetone, 20 °C): δ ϭ 19.4 (s). – Minor diastereoisomer:
(s; CH), 55.3 (s; CH), 91.9 (s; C5H5), 169.1 (s; HNCO), 177.2 [d,
3
3J(P,C) ϭ 3 Hz, COORe], 177.3 [d, J(P,C) ϭ 2 Hz, COORe]. – 31
P
NMR (162 MHz, [D6]acetone, 20 °C): δ ϭ 21.2 (s), 21.4 (s). – IR
(CH2Cl2): ν˜ ϭ 1674 cm–1 (NO). – C28H28N2O4PReS (705.8) calcd
C 47.65, H 4.00, N 3.97, S 4.54; found C 47.52, H 4.00, N 3.65,
S 4.46.
3
1H NMR (400 MHz, [D6]acetone, 20 °C): δ ϭ 1.19 [t, J(H,H) ϭ
7.1 Hz, 3 H; CH3], 1.93 (s, 3 H; CH3), 2.71 [dd, 2J(H,H) ϭ 13.2
Hz, 3J(H,H) ϭ 4.1 Hz, 1 H; SCH2], 2.99–3.06 (m, 1 H; SCH2),
[ CpRe( NO) ( PPh3) ( SCH2CH( NHAc) COOH) ] (13a, b): The
material from the above reaction was dissolved in acetone and
stirred for 3 d at 20 °C. The product was isolated by evaporation
and crystallization from benzene/pentane. NMR analysis revealed
13a, b in 17% de and some residual 12a,b which does not disappear
even after refluxing. Yield 229 mg (81%, based on 4), dec. 216 °C. –
3
4.09 [q, J(H,H) ϭ 7.0 Hz, 2 H; OCH2], 4.43 (m, 1 H; CH), 5.35
3
(s, 5 H; C5H5), 6.90 [d, J(H,H) ϭ 5.5 Hz, 1 H; NH]. – 13C NMR
(100 MHz, CDCl3, 20 °C): δ ϭ 14.2 (s; CH3), 23.0 (s; CH3), 42.0
3
[d, J(P,C) ϭ 11 Hz ; SCH2], 55.3 (s; CH), 61.0 (s; OCH2), 91.6 (s;
C5H5), 170.2, 171.6 (s; HNCO and COOEt). – 31P NMR (162
MHz, [D6]acetone, 20 °C): δ ϭ 18.9 (s). – IR (CH2Cl2): ν˜ ϭ 1748
(COOMe), 1651 cm–1 (NO). – C30H32N2O4PReS (733.8) calcd C
49.10, H 4.40, N 3.82, S 4.37; found C 49.54, H 4.95, N 3.46,
S 4.20.
1
Major diastereoisomer: H NMR (400 MHz, [D6]acetone, 20 °C):
δ ϭ 1.96 (s, 3 H; CH3), 2.76, 3.07 [AB system of d, 2J(H,H) ϭ 13.1
Hz, 3J(H,H) ϭ 8.1 Hz, 3J(H,H) ϭ 4.2 Hz, 2 H; SCH2], 4.44 [dd,
3J(H,H) ϭ 8.1 Hz, 3J(H,H) ϭ 4.2 Hz, 1 H; CH], 5.35 (s, 5 H;
C5H5), NH and OH signals not detected. – 13C NMR (100 MHz,
[D6]acetone, 20 °C): δ ϭ 22.8 (s; CH3), 43.0 [d, 3J(P,C) ϭ 8 Hz;
SCH2], 56.4 (s; CH), 92.5 [d, 2J(P,C) ϭ 1 Hz; C5H5], 170.4 (s;
HNCO), 173.1 (s; COOH). – 31P NMR (162 MHz, C6D6, 20 °C):
δ ϭ 19.4 (s). – Minor diastereoisomer: 1H NMR (400 MHz, [D6]a-
cetone, 20 °C): δ ϭ 1.97 (s, 3 H; CH3), 2.71, 2.86 [AB system of d,
2J(H,H) ϭ 12.8 Hz, 3J(H,H) ϭ 9.3 Hz, 3J(H,H) ϭ 5.5 Hz, 2 H;
[ CpRe( NO) ( PPh3) ( SCH2CH2NHAc) ] (8): A suspension of
Na2CO3 • 10 H2O (286 mg, 1.00 mmol) and N-acetylcysteamine
(60 mg, 0.50 mmol) in THF (40 ml) was stirred 1 h at 20 °C. To
this, a solution of 4 (281 mg, 0.40 mmol) in THF (20 ml) and
ethanol (20 ml) was added and the mixture stirred again for 1 h. All
volatiles were then removed under vacuum, the residue dissolved in
benzene and filtered over Celite, and the product precipitated by
adding pentane. Yield 249 mg (94%).
3
3
SCH2), 4.60 (dd, J(H,H) ϭ 9.3 Hz, J(H,H) ϭ 5.6 Hz, 1 H; CH],
5.45 (s, 5 H; C5H5), NH and OH signals not detected. – 13C NMR
(100 MHz, [D6]acetone, 20 °C): δ ϭ 22.8 (s; CH3), 41.7 (d,
3J(P,C) ϭ 8 Hz; SCH2), 55.6 (s; CH), 92.8 (s; C5H5), 169.9 (s;
HNCO), 172.9 (s; COOH). – 31P NMR (162 MHz, C6D6, 20 °C):
δ ϭ 19.3 (s). – IR (CH2Cl2): ν˜ ϭ 1749 (COOH), 1657 (NO), 1607
cm–1 (CONH).
[ CpRe( NO) ( PPh3) ( SCH2CH2COOMe) ] (10): This compound
was prepared analogously from 4 and ethyl (3-mercapto)propion-
1
ate. Yield 241 mg (91%), dec. 69 °C (dec). – H NMR (400 MHz,
C6D6, 20 °C): δ ϭ 2.74–2.82 (m, 1 H; CH2), 2.93 (m, 2 H; CH2),
3.24–3.33 (m, 1 H; CH2), 3.37 (s, 3 H; OCH3), 4.83 (s, 5 H; C5H5). –
3
[ CpRe( NO) ( PPh3) ( SCH2CH( NHAc) COOMe) ] (14a, b): To a
solution of 13a, b (200 mg, 0.28 mmol) in methanol (10 ml) a few
droplets of HBF4 (54% in ether) were added. The mixture was CO). – 31P NMR (162 MHz, C6D6, 20 °C): δ ϭ 20.0 (s). – IR
13C NMR (100 MHz, C6D6, 20 °C): δ ϭ 38.1 [d, J(P,C) ϭ 8 Hz;
SCH2], 40.1 (s; CH2), 50.9 (s; OCH3), 91.3 (s; C5H5), 173.3 (s;
stirred 3 d at 20 °C. After evaporation to dryness the residue was (CH2Cl2): ν˜
ϭ
1736 (COOMe), 1646 cmϪ1 (NO).
–
chromatographed over silica using THF/ether as an eluent. The
product zone was evaporated and the residue recrystallized from
C27H27NO3PReS (662.8) calcd C 48.93, H 4.11, N 2.11, S 4.84;
found C 49.16, H 4.16, N 2.07, S 4.59.
Eur. J. Inorg. Chem. 1998, 2055Ϫ2061
2059

N. Burzlaff, W. A. Schenk
FULL PAPER
3
[ CpRe( NO) ( PPh3) ( SCH2CH2C( O) NHCH2Ph) ] (11): This
compound was prepared analogously from 4 and (3-mercaptopro-
pionyl)benzylamine. Yield 221 mg (75%), m.p. 39 °C. – H NMR
Hz, J(H,H) ϭ 4.2 Hz, 1 H; CH], 4.88 (s, 5 H; C5H5). – 13C NMR
(100 MHz, C6D6, 20 °C): δ ϭ 17.6 (s; CH3), 25.0 (s; CH2), 29.3 (s;
CH2), 43.4 (s; CH), 47.0 (s; CH2), 47.1 [d, J(P,C) ϭ 8 Hz; SCH2],
1
3
(400 MHz, [D6]acetone, 20 °C): δ ϭ 2.39–2.47 (m, 1 H; CH2), 2.51– 51.4 (s; OCH3), 59.1 (s; CH), 91.7 (s; C5H5), 173.3, 175.1 (s; CO). –
3
2.65 (m, 2 H; CH2), 2.90–2.97 (m, 1 H; CH2), 4.40 [d, J(H,H) ϭ 31P NMR (162 MHz, C6D6, 20 °C): δ ϭ 20.3 (s). – IR (CH2Cl2):
5.6 Hz, 2 H; NCH2], 5.30 (s, 5 H; C5H5), 7.60 [t, 3J(H,H) ϭ 5.6
ν˜ ϭ 1744 (COOMe), 1633 cmϪ1 (NO). – C33H36N2O4PReS (773.9)
Hz, 1 H; NH]. – 13C NMR (100 MHz, [D6]acetone, 20 °C): δ ϭ calcd C 51.22, H 4.69, N 3.62, S 4.14; found C 50.93, H 4.48, N
3
38.3 [d, J(P,C) ϭ 8 Hz; SCH2], 42.1 (s; CH2), 43.2 (s; CH2), 92.5
(s; C5H5), 173.0 (s; CO). – 31P NMR (162 MHz, [D6]acetone,
20°C): δ ϭ 19.5 (s). – IR (CH2Cl2) nu(tilde) ϭ 1654 cm–1 (NO). –
C33H32N2O2PReS (737.9) calcd C 53.72, H 4.37, N 3.80, S 4.35;
found C 53.76, H 4.64, N 3.77, S 4.67.
3.56, S 4.10.
X-Ray Structure Determination of ( R,R) -[ CpRe( NO) ( PPh3) -
( SCH2CH( NC8H4O2) COOMe) ] (16a): C35H30N2O5PReS, molec-
ular mass 807.9, crystal size 0.6 ϫ 0.3 ϫ 0.1 mm, obtained from a
saturated acetone solution; monoclinic crystal system, space group
˚
[ CpRe( NO) ( PPh3) ( SCH2CH( NC8H4O2)COOMe)] (16a, b):
(R)-N-Phthaloylcysteine (200 mg, 0.80 mmol) was dissolved in
ether (15 ml) and treated at 20 °C with a slight excess of diazometh-
ane. After 15 min all volatiles were removed under vacuum and the
residue treated with hydrated sodium carbonate and 4 as described
above. After chromatography over silica using dichloromethane/
acetone (10 lon1) as an eluent and subsequent crystallization from
benzene/pentane the product was isolated as a 1:1 mixture of dia-
stereoisomers. Yield 181 mg (56%), dec. 214 °C. From a concen-
trated solution in acetone the pure (R,R) form separates as orange
crystals. – (R,R) Diastereoisomer 16a: 1H NMR (400 MHz, CDCl3,
P21 (No. 4), a ϭ 8.594(2), b ϭ 17.566(4), c ϭ 10.801(3) A, β ϭ
3
95.269(12)°; V ϭ 1623.8(7) A , Z ϭ 2, dcalcd ϭ 1.652 g cmϪ3; µ(Mo-
˚
Kα) ϭ 2.05 cm–1. Data were collected at 293 K in the range 2° <
Θ < 27° from one fourth of the reflection sphere (Enraf-Nonius
CAD4 diffractometer, graphite monochromator, Mo-Kα radiation,
˚
λ ϭ 0.70930 A). Of the 3877 measured reflections 3641 were sym-
metry-independent and 3456 classified as observed [IO > 2σ(IO)].
The structure was solved by the Patterson method by using the
program package SHELXS 86[27] with hydrogen atoms included in
their calculated positions. Refinement using the program package
SHELXL 93[28] gave R1 ϭ 0.017, wR2 ϭ 0.040, Flack param-
eter lon –0.002(6). The 5 highest maxima of a final difference
Fourier map were below 0.28 e A–3. Further details of the structure
˚
determination may be obtained from the Fachinformationszentrum
Karlsruhe, D-76344 Eggenstein-Leopoldshafen, on quoting the de-
pository number 408461.
2
3
20 °C): δ ϭ 3.05 [dd, J(H,H) ϭ 13.6 Hz, J(H,H) ϭ 3.6 Hz, 1 H;
SCH2], 3.72 (s, 3 H; OCH3), 3.89 [ddd, 2J(H,H) ϭ 13.6 Hz,
3J(H,H) ϭ 11.6 Hz, 4J(P,H) ϭ 1.0 Hz, 1 H; SCH2], 5.21 [dd,
3J(H,H) ϭ 11.6 Hz, 3J(H,H) ϭ 3.6 Hz, 1 H; CH], 5.22 (s, 5 H;
C5H5). – 13C NMR (100 MHz, CDCl3, 20 °C): δ ϭ 41.2 [d,
3J(P,C) ϭ 9 Hz ; SCH2], 52.6 (s; OCH3), 56.2 (s; CH), 91.5 (s;
C5H5), 167.5, 170.2 (s; CO). – 31P NMR (162 MHz, CDCl3, 20°C):
δ ϭ 18.9 (s). – (S,R) Diastereoisomer 16b: 1H NMR (400 MHz,
[1]
N. Burzlaff, M. Hagel, W. A. Schenk, Z. Naturforsch., B 1998,
53, 893Ϫ899.
2
3
[2]
CDCl3, 20 °C): δ ϭ 3.35 [dd, J(H,H) ϭ 13.2 Hz, J(H,H) ϭ 11.2
E. Block, J. Zubieta in Advances in Sulfur Chemistry (Ed.: E.
2
3
Hz, 1 H; SCH2], 3.68 [dd, J(H,H) ϭ 13.2 Hz, J(H,H) ϭ 4.8 Hz,,
1 H; SCH2], 3.69 (s, 3 H; OCH3), 4.98 [dd, 3J(H,H) ϭ 11.0 Hz,
3J(H,H) ϭ 4.6 Hz, 1 H; CH], 5.19 (s, 5 H; C5H5). – 13C NMR (100
MHz, CDCl3, 20 °C): δ ϭ 41.8 [d, 3J(P,C) ϭ 9 Hz ; SCH2], 52.5
Block), JAI Press, London, 1994, pp. 133–193.
[3]
M. T. Ashby, Comments Inorg. Chem. 1990, 10, 297–313.
[4]
B. Krebs, G. Henkel, Angew. Chem. 1991, 103, 785–804; Angew.
Chem. Int. Ed. Engl. 1991, 30, 769–788.
[5]
J. E. Baldwin, M. Bradley, Chem. Rev. 1990, 90, 1079–1088.
(s; OCH3), 56.3 (s; CH), 91.5 (s; C5H5), 167.9, 169.5 (s; CO). – 31
P
P. L. Roach, I. J. Clifton, C. M. H. Hensgens, N. Shibata, C. J.
[6]
Schofield, J. Hajdu, J. E. Baldwin, Nature 1997, 387, 827–830.
NMR (162 MHz, CDCl3, 20 °C): δ ϭ 19.0 (s). – IR (CH2Cl2):
ν˜ ϭ 1777, 1720 (phthalimide), 1743 (COOMe), 1649 cm–1 (NO). –
C35H30N2O5PReS (807.9) calcd C 52.04, H 3.74, N 3.47, S 3.97;
found C 51.74, H 4.00, N 3.37, S 3.97.
[7]
W. A. Schenk, T. Stur, E. Dombrowski, Inorg. Chem. 1992, 31,
723–724.
[8]
W. A. Schenk, T. Stur, E. Dombrowski, J. Organomet. Chem.
1994, 472, 257–273.
[9]
W. A. Schenk, N. Burzlaff, H. Burzlaff, Z. Naturforsch. B 1994,
[ CpRe( NO) ( PPh3) ( SCH2CH ( M e) C( O) NC4H 7COOMe) ]
(17a, b): N-[(S)-3-mercapto-2-methylpropionyl]-S-proline (174 mg,
0.80 mmol) was converted to its methyl ester and reacted with 4 as
described above. After chromatography over silica using dichloro-
methane/acetone (4:1) as an eluent and subsequent crystallization
from benzene/pentane the product was isolated as a 1:1 mixture
of diastereoisomers. Yield 229 mg (74%), m.p. 162 °C. A further
crystallization from benzene/pentane yielded a sample with 15%
49, 1633–1639.
[10]
H. Fischer, U. Gerbing, K. Treier, J. Hofmann, Chem. Ber. 1990,
123, 725–732.
[11]
H. Fischer, C. Kalbas, U. Gerbing, J. Chem. Soc. Chem. Com-
mun. 1992, 563–564.
[12]
H. Fischer, A. Ruchay, R. Stumpf, C. Kalbas, J. Organomet.
Chem. 1993, 459, 249–255.
[13]
W. Tam, G. Y. Lin, W. K. Wong, W. A. Kiel, V. K. Wong, J. A.
Gladysz, J. Am. Chem. Soc. 1982, 104, 141–152.
[14]
S. K. Agbossou, J. M. Fernandez, J. A. Gladysz, Inorg. Chem.
1
de. – Major diastereoisomer: H NMR (400 MHz, C6D6, 20 °C):
1990, 29, 476–480.
δ ϭ 1.19–1.40 (m, 2 H; CH2), 1.32 [d, 3J(H,H) ϭ 6.8 Hz, 3 H;
S. K. Agbossou, C. Roger, A. Igau, J. A. Gladysz, Inorg. Chem.
[15]
1992, 31, 419–424.
CH3], 1.45–1.70 (m, 3 H; CH2, and CH), 2.83 (m, 1 H; CH2), 2.92
[16]
S. Wolfe, J. C. Godfrey, C. T. Holdrege, Y. G. Perron, Can. J.
3
3
[dd, J(H,H) ϭ 11.6 Hz, J(H,H) ϭ 4.0 Hz, 1 H; CH2], 3.34 (s, 3
Chem. 1968, 46, 2549–2559.
3
[17]
H; OCH3), 3.45–3.55 (m, 2 H; CH2), 4.64 [t, J(H,H) ϭ 5.6 Hz, 1
H; CH], 4.95 (s, 5 H; C5H5). – 13C NMR (100 MHz, C6D6, 20 °C):
δ ϭ 18.6 (s; CH3), 24.9 (s; CH2), 29.2 (s; CH2), 43.4 (s; CH), 46.9
P. C. Cagle, A. M. Arif, J. A. Gladysz, J. Am. Chem. Soc. 1994,
116, 3655–3656.
[18]
P. C. Cagle, O. Meyer, D. Vichard, K. Weickhardt, A. M. Arif,
J. A. Gladysz, Organometallics 1996, 15, 194–204.
3
(s; CH2), 49.0 [d, J(P,C) ϭ 8 Hz ; SCH2], 51.4 (s; OCH3), 58.9 (s;
[19]
J. J. Kowalczyk, S. K. Agbossou, J. A. Gladysz, J. Organomet.
CH), 91.7 (s; C5H5), 173.2, 175.0 (s; CO). – 31P NMR (162 MHz,
C6D6, 20 °C): δ ϭ 21.0 (s). – Minor diastereoisomer: 1H NMR
(400 MHz, C6D6, 20 °C): δ ϭ 1.19–1.40 (m, 2 H; CH2), 1.50 [d,
3J(H,H) ϭ 6.8 Hz, 3 H; CH3], 1.45–1.70 (m, 2 H; CH2), 1.77–1.85
(m, 1 H; CH), 2.99 (m, 1 H; CH2), 3.20–3.27 (m, 1 H; CH2), 3.37
Chem. 1990, 397, 333–346.
[20]
J. A. Gladysz, B. J. Boone, Angew. Chem. 1997, 109, 566–602;
Angew. Chem. Int. Ed. Engl. 1997, 36, 550–583.
[21]
J. M. Fernandez, J. A. Gladysz, Organometallics 1989, 8, 207–
219.
[22]
G. Jaouen, A. Vessieres, I. S. Butler, Acc. Chem. Res. 1993, 26,
3
(s, 3 H; OCH3), 3.61–3.69 (m, 2 H; CH2), 4.80 [dd, J(H,H) ϭ 8.6
361–369.
2060
Eur. J. Inorg. Chem. 1998, 2055Ϫ2061

Enantioselective Organic Syntheses Using Chiral Transition Metal Complexes, 7
FULL PAPER
[23]
[26]
[27]
[28]
C. Giacovazzo, H. L. Monaco, D. Viterbo, F. Scordari, G. Gilli,
G. Zanotti, M. Catti, Fundamentals of Crystallography, Oxford
University Press, Oxford, 1992, pp. 538–541.
T. Kametani, K. Kigasawa, M. Hiiragi, N. Wagatsuma, T. Ko-
hagizawa, H. Inoue, Heterocycles 1978, 9, 831–840.
G. M. Sheldrick, SHELXS 86, Program for Crystal Structure
Solution, Universität Göttingen, Germany, 1986.
G. M. Sheldrick, SHELXL 93, Program for Crystal Structure
Refinement, Universität Göttingen, Germany, 1993.
[I98241]
[24]
[25]
R. E. Eibeck, Inorg. Synth. 1963, 7, 128–131.
A. Schöberl, A. Wagner in Methoden der Organischen Chemie
( Houbel-Weyl) , 4th Edition, Vol. 9, Thieme, Stuttgart, 1955,
p. 45.
Eur. J. Inorg. Chem. 1998, 2055Ϫ2061
2061