Unique tripodal chiral tertiary amine, 2,6-trans-1,2,6-trisubstituted piperidine with pyridine and bis(phenol) donor groups: Its stereoselective coordination to titanium(IV) ion

Article abstract of DOI:10.1016/j.jorganchem.2006.07.045

A new optically active functionalized tertiary amine, (2R,6R)-2,6-bis(2-hydroxyphenyl)-1-(2-pyridylmethyl)piperidine {(R,R)-1}, was synthesized and its complexation behavior as a tripodal ligand was elucidated with titanium(IV) ion. Protonolysis of Ti(OPr

Full text of DOI:10.1016/j.jorganchem.2006.07.045

Journal of Organometallic Chemistry 692 (2007) 645–653
www.elsevier.com/locate/jorganchem
Unique tripodal chiral tertiary amine, 2,6-trans-1,2,6-
trisubstituted piperidine with pyridine and bis(phenol) donor groups:
Its stereoselective coordination to titanium(IV) ion
*
Tohru Okamatsu, Ryo Irie , Tsutomu Katsuki
Department of Chemistry, Faculty of Science, Graduate School, Kyushu University, 33, Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
Received 31 March 2006; received in revised form 24 July 2006; accepted 25 July 2006
Available online 1 September 2006
Abstract
A new optically active functionalized tertiary amine, (2R,6R)-2,6-bis(2-hydroxyphenyl)-1-(2-pyridylmethyl)piperidine {(R,R)-1}, was
synthesized and its complexation behavior as a tripodal ligand was elucidated with titanium(IV) ion. Protonolysis of Ti(OPr-i)
R,R)-1 and H O in a stepwise manner led to the formation of C -symmetric tris(l-oxo)trititanium(IV,IV,IV) complex [Ti (l-O)
L = diphenolato anion of (R,R)-1} with unified chiralities induced at the metal center (A) and by the conformations of the N O chelate
loops (k) as well as the six-membered non-planner chair-like (Ti-l-O) ring core as defined by X-ray crystallography. These stereochem-
4
with
(
{
2
3
3
L
3
3
]
ꢀ
3
ical issues are principally regulated by the stereogenic centers on the ligand and a chair conformation of the piperidine skeleton, which
settle an enantiotopos-differentiating cis(Ophenolato–Ophenolato) binding mode by unequivocally locating one Ophenolato in an axial position
and the other Ophenolato in an equatorial plane.
ꢁ
2006 Elsevier B.V. All rights reserved.
Keywords: Chiral tetradentate tripodal ligand; Chiral piperidine; Tris(l-oxo)trititanium complex; Chirality-at-metal
1
. Introduction
to endow the metal complexes with unique catalytic prop-
erties. Thus, asymmetric catalyses of transition metal com-
plexes coordinated with an optically active tripodal tertiary
amine ligand should be of potential interest [6]. In fact, cis-
b complexes possessing the same topological alignment of
the ligating atoms but another connectivity for the chelate
loops, have been demonstrated to catalyze a variety of
characteristic asymmetric reactions in the past a few years
[7,8]. In this context, we have been involved in the studies
on asymmetric catalyses by octahedral metal complexes
Tripodal ligands, which are characterized by a facial
coordination to metal ions, have recently gained consider-
able attention and found applications in various fields of
research such as bioinorganic chemistry [1] and catalytic
olefin polymerization [2]. As among the most reliable tac-
tics to construct tetradentate ligands with a tripodal nature,
trialkyl amine platforms have been long utilized as re-
0
presented by tris(2-pyridylmethyl)amine [3], N,N -bis(2-
ꢀ
ꢀ
ꢀ
hydroxybenzyl)-2-picolylamine [4], and tris{2-(R)-4-phe-
nyl-1,3-oxazolinylmethyl}amine [5] (Fig. 1). When these
compounds are coordinated to transition metal ions with
an octahedral geometry, the arylmethyl side donor atoms
are aligned facially on the coordination sphere to leave
mutually cis-disposed two active sites, which are supposed
with tripodal ligands of {A (N B) A}-type such as bis(2-
hydroxybenzyl)-2-picolylamine, which are capable of
adopting two different symmetries, either C or C , upon
1
s
coordination (Scheme 1) [9]. The C -isomer is of particular
1
note because it is intrinsically chiral at the metal center (A
or C) and the chirality (k or d) is also induced by the che-
late-ring conformation [10], as in the case of cis-b com-
plexes [7,8]. Since the isomers in Scheme 1 can be
generally all accessible, an effective method to select an
*
Corresponding author.
E-mail address: irie.scc@mbox.nc.kyushu-u.ac.jp (R. Irie).
0
022-328X/$ - see front matter ꢁ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.07.045

646
T. Okamatsu et al. / Journal of Organometallic Chemistry 692 (2007) 645–653
O
Ph
Ph
OH
N
N
O
N
N
N
L
N
N
N
N
N
O
N
L
M
L
HO
Ph
Fig. 1. Representative tetradentate tripodal ligands and an illustration for their facial coordination mode (L = donor group).
enantiomer with the desired C -symmetry is required. To
1
OH
this end, chiral 2,6-trans-1,2,6-trisubstituted piperidine
derivatives should be promising because they should favor
a chair-like ring conformation for the piperidine backbone
to dispose the substituent at C2(6) in axial and the other
one at C6(2) in equatorial positions, leading to the desired
6
2
N
M
O
N
N
O
X
OH
X
N
ꢀ
cis(O O)- and enantio-selective binding to the metal center
homochiral
1
(
Fig. 2). Hence, we set 2,6-trans-bis(2-hydroxyphenyl)-1-(2-
pyridylmethyl)amine 1 as a prototypical ligand to meet the
criteria described above [11]. It should be noted that the
two phenol groups in 1 are homotopic in a dynamical sense
owing to the rapid ring flipping of the piperidine and the
inversion of the amine nitrogen atom so that 1 would bind
to an octahedral metal center with a uniformed chirality
and topicity. We were rather surprised to realize that opti-
cally active trialkyl amines of {A (N B) A} type had not
been sufficiently qualified as chiral tripodal ligands in
metal-catalyzed asymmetric organic transformations in
Fig. 2. Optically active tripodal ligand 1 based on 2,6-trans-1,2,6-
trisubstituted piperidine platform for a cis(O O)- and enantio-selective
binding to the metal center.
ꢀ
2. Results and discussion
ꢀ
ꢀ
ꢀ
2.1. Synthesis of (R,R)-1
Commercially available dicoumarol was converted to
1,5-pentanedione 2 quantitatively by hydrolysis and subse-
quent decarboxylation according to the literature proce-
dure (Scheme 2) [14]. After the phenol hydroxy groups of
2 were protected as the corresponding methanesulfonates,
we first attempted various catalytic asymmetric reduction
contrast to the recent investigations on the C -symmetric
3
families [12,13].
To shed light on the structural feature of this unique chi-
ral tripodal ligand 1 and its metal complex, we herein
report our studies on its synthesis, characterization, and
stereoselective coordination to titanium(IV) ion.
of 3 and found that (ꢀ)-(Ipc) BCl gave optically active 4
2
with excellent enantio- and diastereo-selectivities, and good
chemical yield (99% ee, anti/syn P 99:1, 68%) [15]. How-
ever, the methanesulfonylation of 4 followed by the treat-
ment with 2-picolylamine led to a 1:2 mixture of dl- and
meso-2,6-disubstituted piperidine derivative 5. The loss of
the stereochemistry in this ring formation was inevitably
LB
LA
LB
LA
N
LA
N
LA
attributed to an S 1-type displacement of the methanesulf-
N
onates at the benzylic positions, which are highly prone to
generate a carbocation intermediate. Although this stereo-
chemical problem has not been overcome, we found that
the dl- and meso-forms of 1 were readily separable by col-
umn chromatography on silica gel. Thus, we performed
[
MX2]
[MX2]
B
B
M
A
B
N
N
N
A
NaBH reduction of 3 to a dl- and meso-mixture of diol
4
X
M
A
A
X
A
M
4, the former of which was separated by column chroma-
tography and transformed to 5 as mentioned above fol-
lowed by alkaline methanolysis of the methanesulfonyl
groups to 1 [16]. The diastereomeric mixtures were sepa-
rated to isolate dl-1 in 66% yield from 3. Recrystallization
of dl-1 from ethyl acetate afforded single crystals suitable
for X-ray crystallography, which unambiguously deter-
mined its molecular structure (Fig. 3). Interestingly, the
X
X
X
A
X
C1
C1
Cs
chiral-at-metal
achiral
Scheme 1. Two possible symmetries of octahedral metal complex coor-
dinated with tetradentate tripodal ligand of {A (N B) A} type (the
connectivity for the ligating atoms is symbolized by ). Pre-coordinating
groups in the ligand are denoted by LA,B, their specific ligating atoms by A
and B, and ancillary ligands by X.
ꢀ
ꢀ
ꢀ
ꢀ
˚
short O–N distances, 2.787 A for the O(1)ꢁ ꢁ ꢁN(1) and
˚
2.662 A for the O(2)ꢁ ꢁ ꢁN(2), apparently indicated hydrogen

T. Okamatsu et al. / Journal of Organometallic Chemistry 692 (2007) 645–653
647
OH
O
OH
O
OR
O
O
OR
OMs OH OH OMs
ref.10
b
3
3
O O
4
2
3
: R = H
: R = Ms
a
R
R
OH
OH
c, d, e
N
N
f, g
N
N
5
: R = Ms
(R,R)-1
a
dl-1: R = H
Scheme 2. Reaction conditions: (a) MsCl (2.1 equiv), Et
and meso-forms by column chromatography on silica gel (50%); (c) MsCl (2.5 equiv), Et
3
N (2.1 equiv), CH
2
Cl
2
, rt, 1.5 h (99%); (b) NaBH
N (2.5 equiv), CH
9.5 equiv), rt, overnight (70%); (d) KOH, MeOH, 1,4-dioxane, 50 ꢂC (94%); (e) separation of the diastereomers by column chromatography on silica gel;
4
(2.1 equiv), EtOH, rt, then separation of the dl-
3
2
Cl
2
, ꢀ20 ꢂC, 2.5 h, then 2-picolylamine
(
(
0
3
f) (R,R)-O,O -dibenzoyltartric acid (1 equiv), AcOEt, recrystallization; (g) satd. NaHCO , AcOEt (46% for two steps).
CH Cl at room temperature to produce an octahedral
2
2
titanium complex [TiL(OPr-i) ] {L = diphenolato anion
2
1
of (R,R)-1} (6) as was evident by H NMR analysis
(Scheme 3). Interestingly, 6 was found to slowly undertake
further protonolysis with H O in CDCl to grow single
2
3
crystals
of
tris(l-oxo)trititanium(IV,IV,IV)complex
[
Ti L (l-O) ] Æ 4CDCl (7), whose virtually C -symmetric
3
3
3
3
3
structure was unequivocally evaluated by X-ray crystallog-
raphy as shown in Fig. 4a. Additionally, refinement of the
flack parameter of 7 established its absolute configuration
to be (2R,6R) for the ligand part. Each Ti(IV) center
adopts a distorted octahedral geometry surrounded by
the Npiperidine, the Npyridine, and the two Ophenolato of
(R,R)-1 and the two l-O atoms (Fig. 5a, Table 1). One
Fig. 3. An ORTEP diagram for the X-ray structure of dl-1 with thermal
ellipsoids at 50% probability. The hydrogen atoms except for those at O(1)
and O(2) are omitted for clarity. The hydrogen bonding interactions
between the phenolic hydroxyls and the amine nitrogen atoms are
indicated by dashed lines.
of the most striking aspects noted in the crystal structure
ꢀ
of 7 is that (R,R)-1 in fact adopts a cis(Ophenolato Ophenolato
)
coordination to render the metal center chiral (A, Fig. 5b).
ꢀ
Furthermore, it was also indicated that the two N O chelate
rings in the ligand favored k chiral conformation upon
coordination (Fig. 5c). These stereochemical regulations
are mainly attained by the fact that the piperidine backbone
of (R,R)-1 is fixed at a chair conformation to discreetly
locate the N-pyridylmethyl and one of the phenolato groups
in axial, and the other one in equatorial positions, which is
supposed to strongly direct the Npiperidine and one Ophenolato
in the equatorial coordination plane in a cis-fashion and the
Npyridine and the other Ophenolato in either apical site,
respectively (Fig. 5a). The analogous achiral tripodal
ligands to (R,R)-1 have been demonstrated to adopt
either C {cis(Ophenolato–Ophenolato)}- [4g,19] or C {trans-
bonding interaction between the phenolic hydroxyls and
the amine nitrogen atoms to create a chiral concave sphere
around the Npiperidine [17]. Finally, the optical resolution of
dl-1 was performed by its derivation to a 1:1 salt with
0
(
R,R)-O,O -dibenzoyltartaric acid and recrystallization of
the diastereomeric salt from ethyl acetate. The absolute
configuration of 1 thus obtained was determined to be
(
2R,6R) by refinement of the Flack parameter of its
tris(l-oxo)trititanium complex (vide infra).
1
s
2.2. Synthesis and structure of the titanium(IV) complexes
of 1
(Ophenolato–Ophenolto)}-symmetry [4a,4e,19c,19f,20] upon
Ti(OPr-i)4, CH2Cl2, rt
i-PrOH (X2)
H O, CDCl , rt
2
3
With (R,R)-1 in hand, we next examined the synthesis
(R,R)-1
[TiL(OPr-i)2]
[TiL(μ-O)]3
and characterization of its titanium(IV) complex to gain
some insights into the stereoselectivity in the complexation
of (R,R)-1 with transition metal ions. Protonolysis of
Ti(OPr-i)4 with (R,R)-1 proceeded quantitatively in
6
7
i-PrOH (X2)
L = diphenolate anion of (R,R)-1
Scheme 3. Successive protonolysis of Ti(OPr-i) with (R,R)-1 and H O.
2

648
T. Okamatsu et al. / Journal of Organometallic Chemistry 692 (2007) 645–653
a
b
O(3)
Ti(B)
O(3)
Ti(B)
O(4)
Ti(A)
O(5)
Ti(C)
O(4)
O(5)
Ti(C)
Ti(A)
Fig. 4. (a) An ORTEP diagram for the X-ray structure of 7 and (b) its [Ti
3
(l-O)
3
] ring core with thermal ellipsoids at 30% probability. Hydrogen atoms
and the solvates (CDCl
3
) are omitted for clarity.
a
c
b
[
1]
(
1A)
O(2A)
O(2A)
N
Ti
μ
-O
[2]
N(1A)
O(1A)
N(2A)
[3]
N(1A)
O
Ti(A)
O(5)
O(3)
μ
-O
Ti
(1A)
or
2A)
C2(6)
[1]
(
N(2A)
O(1A)
Fig. 5. (a) An ORTEP diagram for the mono nuclear unit of 7 with thermal ellipsoids at 50% probability, (b) a schematic representation for an
anticlockwise (A) sense of the steering-wheel defined by the priority rankings of the ligating atoms in the equatorial plane viewed from the O(2A) side
ꢀ
[
10,18], and (c) an illustration for the chiral k conformation induced at the Ti(N O) chelate ring. The numbers in the bracket in (b) stand for the priority
rankings of the ligating atoms.
Table 1
˚
Selected bond lengths (A) and angles (ꢂ) in 7
[
Ti(A)L(l-O
2
)] part
[Ti(B)L(l-O
2
)] part
2
[Ti(C)L(l-O )] part
Ti(A)–N(1)
Ti(A)–N(2)
Ti(A)–O(1)
Ti(A)–O(2)
Ti(A)–O(3)
Ti(A)–O(5)
2.398(5)
2.187(5)
1.962(4)
1.854(4)
1.761(4)
1.916(4)
Ti(B)–N(1B)
Ti(B)–N(2B)
Ti(B)–O(1B)
Ti(B)–O(2B)
Ti(B)–O(3)
Ti(B)–O(4)
2.370(5)
2.209(5)
1.937(4)
1.875(4)
1.758(4)
1.897(4)
Ti(C)–N(1C)
Ti(C)–N(2C)
Ti(C)–O(1C)
Ti(C)–O(2C)
Ti(C)–O(4)
2.393(5)
2.171(5)
1.931(4)
1.859(4)
1.769(4)
1.945(4)
Ti(C)–O(5)
\
\
\
\
\
\
\
\
\
N(1)TiN(2)
N(1)TiO(1)
N(1)TiO(2)
N(1)TiO(5)
O(1)TiO(3)
O(3)TiO(5)
N(1)TiO(3)
N(2)TiO(2)
O(1)TiO(5)
76.52(19)
81.68(18)
83.71(19)
80.99(18)
99.73(19)
97.64(18)
172.86(18)
160.2(2)
\N(1)TiN(2)
\N(1)TiO(1)
\N(1)TiO(2)
\N(1)TiO(3)
\O(1)TiO(4)
\O(3)TiO(4)
\N(1)TiO(4)
\N(2)TiO(2)
\O(1)TiO(3)
93.55(19)
83.26(18)
83.11(19)
80.83(18)
97.44(19)
96.75(19)
172.73(19)
159.1(2)
\N(1)TiN(2)
\N(1)TiO(1)
\N(1)TiO(2)
\N(1)TiO(5)
\O(1)TiO(5)
\O(4)TiO(5)
\N(1)TiO(5)
\N(2)TiO(2)
\O(1)TiO(4)
74.61(19)
80.9(2)
85.8(2)
82.29(18)
96.4(2)
98.12(19)
168.85(19)
160.4(2)
160.0(2)
156.13(19)
159.56(18)
coordination to transition metal ions depending on natures
of the central metals and the ancillary ligating atoms
former C -complexes possessed the same relative stereo-
1
chemical relationship (kd,AC) between the chiralities for
the ligand conformation and at the metal center, respec-
tively [4g,19]. However, to our best knowledge, (R,R)-1 is
(
Scheme 1). The survey on the X-ray structures in the Cam-
bridge Structural Database (CSD) demonstrated that the

T. Okamatsu et al. / Journal of Organometallic Chemistry 692 (2007) 645–653
649
tallography disclosed that (R,R)-1 formed a unique asym-
metric concave site, which might show a unique organo-
catalysis [17]. It was demonstrated that (R,R)-1 reacted
a
(
b
(
4)
O
(4)
O
C)Ti
Ti(B)
(B)Ti
Ti(C)
Ti O(5)
(5)O
Ti
A)
O(3)
(3)O
(
(B)
with Ti(OPr-i) to form primarily an octahedral mono-
4
meric complex [TiL(OPr-i) ] (6) quantitatively as evaluated
by H NMR analysis. In a preliminary study, 6 was demon-
2
observed
not observed
1
Fig. 6. (a) A schematic representation of the six-membered chair-like
conformation of tris(l-oxo)trititainium core structure with a C -symmetry
in 7 and (b) a mirror image, which is not superimposable on the original
one in (a). The longer Ti–O bond in trans to the Ophenolato is shown in a
bold line and the shorter one in cis to the Npiperidine in a solid line.
strated to catalyze asymmetric oxidation of methyl phenyl
sulfide using hydrogen peroxide or its inclusion compound
in urea (UHP) as a terminal oxidant, though the chemical
yield and the enantioselectivity were both insufficient. The
insufficient catalytic turnover number of 6 was in a large
3
part attributed to its gradual protonolysis with H O to a
2
the first enantio- and cis(O
ral tripodal ligand of {A (N B) A} type in the formation of
an octahedral complex.
–Ophenolato)-selective chi-
phenolato
ꢀ
tris(l-oxo)trititanium(IV,IV,IV) complex [Ti L (l-O) ],
3
3
3
ꢀ
ꢀ
which was shown to be catalytically inactive. The unique
virtually C -symmetric trinuclear structure of 7, where each
3
Another characteristic point of view in the crystal struc-
ture of 7 is the Ti and the l-O atoms are deviated up and
titanium atom is coordinated with (R,R)-1 in a tripodal
fashion, was unambiguously determined by X-ray crystal-
lography and its absolute configuration was defined by
refinement of the flack parameter. Notably, (R,R)-1
induced unified multiple chiralities at the metal center
˚
˚
down by 0.46 A and 0.37 A on average, respectively, from
the basal mean plane defined by the rest two Ti and two l-
O atoms to constitute a very shallow six-membered chair-
like conformation for the (Ti-l-O)3 ring (Fig. 6). The
analogous tris(l-oxo)trititanium complexes have been syn-
thesized before predominantly with cyclopentadienyl
anions and its derivatives as supporting ligands [21].
However, it should be noted that, in contrast to these
precedents, the two l-O atoms are unequivalent and the
Ti-l-O bond in trans to the Ophenolato atom is apparently
longer than the one in trans to the Npiperidine atom in a
reflection of a stronger trans influence of the former ligat-
ing atom than the latter one on titanium(IV) ion [19e].
Accordingly, the two different Ti-l-O bonds in length are
ꢀ
(A), the chelate N O rings (k), and the six-membered
non-planner chair-like (Ti-l-O) cycle upon coordination.
3
These configurations are principally regulated by the stere-
ogenic centers on the ligand and a chair conformation of
the piperidine skeleton, which unequivocally locates one
phenolato group in axial and the other in equatorial posi-
tions. The difference in the trans influences of the tertiary
amine nitrogen and the phenolato oxygen atoms, which
unequally affect the Ti-l-O bond lengths in trans to each
atom, is also a key factor to render the six-membered
chair-like conformation of the (Ti-l-O) cycle C -symmet-
3
3
alternately aligned in the (Ti-l-O) cycle in 7 to induce a
3
ric (chiral), biased from C -symmetry (achiral) like cyclo-
3h
chiral conformation with an almost C -symmetry (Fig. 6).
This stereochemical outcome is also ascribed to the charac-
teristic chiral topology of (R,R)-1.
3
hexane. Further studies on asymmetric catalyses by
transition metal complexes of (R,R)-1 and its derivatives
are currently under way in our laboratory.
In conjunction with great success in asymmetric oxida-
tion of sulfides catalyzed by chiral Ti(salen) complex with
a cis-b geometry [22], we examined the same reactions with
mononuclear complex 6. In a preliminary study, 6 (5 mol
4
. Experimental
4.1. General
%
) was demonstrated to catalyze asymmetric oxidation of
1
methyl phenyl sulfide using hydrogen peroxide or its inclu-
sion compound in urea (UHP) as a terminal oxidant, albeit
with an insufficient level of chemo- and enantio-selectivi-
H NMR spectra were recorded at 400 MHz on a JEOL
JNM-AL-400 instrument. IR spectra were obtained with a
SHIMADZU FTIR-8400 instrument. Optical rotations
were measured with a JASCO P-1020 polarimeter. Column
chromatography was conducted on silica gel 60N (spheri-
cal, neutral), 63–210 lm, available from Kanto Chemical
Co. (Japan) and preparative thin-layer chromatography
was performed on 0.5 nm · 20 cm · 20 cm E. Merck silica
gel plate (60 F-254). Enantiomeric excesses were deter-
mined by HPLC (high performance liquid chromatogra-
phy) analysis using SHIMADZU LC-10AT-VP equipped
with an appropriate optically active column, as described
in the footnotes of the corresponding tables. Anhydrous
organic solvents were purchased from Kanto Chemical
Co. (Japan) and used as received. Cyclic meso anhydrides
ties, and chemical yield (with H O : 53% yield, sulfoxide/
2
2
sulfone = 6.9/1, 12% ee for sulfoxide; with UHP: 66%
yield, sulfoxide/sulfone = 1.4/1, 40% ee for sulfoxide).
Under the conditions, 6 underwent protonolysis to 7 that
was proven to be catalytically inactive in a separate reac-
tion, which should account for the low yielding in the
sulfoxidation.
3
. Conclusion
In summary, we synthesized a new chiral tetradentate
ꢀ
ꢀ
ꢀ
tripodal ligand (R,R)-1 of {O (N N) O}-type character-
ized by 2,6-trans-1,2,6-trisubstituted piperidine scaffold
appended with pyridine and phenol groups. Its X-ray crys-
8
and 11 were available from Aldrich and 9 [23] and 10
[
24] were prepared according to the literature procedures.

650
T. Okamatsu et al. / Journal of Organometallic Chemistry 692 (2007) 645–653
4
4
.2. Synthesis of (R,R)-1
(KBr): 3404, 3022, 2948, 2365, 1487, 1450, 1362, 1342,
184, 1151, 1074, 1065, 976, 925, 878, 849, 785, 775,
525 cm . Anal. Calc. for C H O S : C, 51.34; H,
19 24 8 2
1
ꢀ1
.2.1. 1,5-Bis(2-hydroxyphenyl)-1,5-pentanedione (2) [14]
Commercially available dicoumarol (8.45 g, 25.1 mmol)
5.44. Found: C, 51.36; H, 5.44%.
was stirred with aq. KOH (20%, 200 mL) at reflux for 4 h.
The reaction mixture was neutralized with conc. HCl
4.2.4. (ꢀ)-1,5-anti-Bis(2-methanesulfonyloxyphenyl)-1,5-
pentanediol (4)
(
60 mL) and extracted with AcOEt (3 · 200 mL). The com-
bined organic layer was washed with brine, dried over
To a round bottomed flask containing (Ipc) BCl (8.0 g,
2
Na SO , and concentrated to dryness in vacuo to give 2
25 mmol) and 2 (5.2 g, 12 mmol) immersed in a cooling
bath at ꢀ78 ꢂC (methanol–dry ice), was slowly added
anhydrous THF (60 mL) under nitrogen atmosphere.
The mixture was stirred at the temperature for 2 h and
additional 15 h at room temperature. After cooled to
0 ꢂC, the reaction mixture was treated with a suspension
of bis(hydroxyethyl)amine (2.88 mL, 27.4 mmol) in anhy-
2
4
(
7.0 g, 98%). The crude product was used in the next reac-
1
tion without further purification. H NMR (400 MHz): d
2.27 (s, 2H), 7.80 (dd, J = 1.5 and 8.1 Hz, 2H), 7.47
ddd, J = 1.5, 7.1, and 8.4 Hz, 2H), 6.99 (dd, J = 1.0 and
1
(
8
3
.4 Hz, 2H), 6.91 (ddd, J = 1.0, 8.1, and 8.4 Hz, 2H),
.16 (t, J = 7.0 Hz, 4H), 2.22 (qt, J = 7.0 Hz, 2H).
drous Et O (60 mL) and then allowed to warm to room
2
4.2.2. 1,5-Bis(2-methanesulfonyloxyphenyl)-1,5-
pentanedione (3)
temperature with stirring overnight. The resulting white
precipitates were removed by filtration through a pad of
Celite and the filtrate was evaporated. The residue (anti/
syn P 99:1, >99% ee) was subjected to column chroma-
tography on silica gel (hexane/AcOEt/acetic acid = 4/6/
0.1) to obtain 4 (3.6 g, 69%). The enantiomeric excess
was determined by HPLC analysis using an optically
active column (DAICEL CHIRALCELL OD-H, hex-
To a solution of 2 (70.0 g, 246 mmol) in anhydrous
CH Cl (600 mL) were added Et N (72.0 mL, 517 mmol)
2
2
3
and MsCl (40.0 mL, 517 mmol) and the mixture was stirred
at room temperature for 1.5 h under nitrogen atmosphere.
The volatiles were evaporated and the resulting residue was
partitioned into AcOEt (600 mL) and H O (300 mL). The
2
23
two phases were separated and the aqueous layer was
extracted with AcOEt (2 · 600 mL). The combined organic
layer was washed with brine, dried over Na SO , and evap-
ane/2-propanol = 80/20, 0.5 mL/min). ½aꢂ ꢀ61.2 (c 0.1,
D
EtOH). Mp 104–105 ꢂC.
2
4
orated to give 3 as crystals (107 g, 98.7%). The product was
used for the next reaction without further purification. The
physical properties were collected for a sample purified by
4.2.5. (2RS,6RS)-2,6-Bis(2-hydroxyphenyl)-1-
pyridylmethylpiperadine (dl-1)
To a solution of MsCl (8.70 mL, 113 mmol) in CH Cl
2
2
1
TLC (hexane/AcOEt 4:1). Mp 68–69 ꢂC. H NMR
(150 mL) at ꢀ20 ꢂC was dropwise added a solution of 4
(
(
400 MHz): d 7.71 (dd, J = 1.1 and 7.7 Hz, 2H), 7.54
ddd, J = 1.1, 8.3, and 8.8 Hz, 2H), 7.43 (d, J = 8.8 Hz,
(20.0 g, 45 mmol) and Et N (15.7 mL, 113 mmol) in anhy-
3
drous CH Cl (150 mL) under nitrogen atmosphere. The
2
2
2
6
H), 7.40 (ddd, J = 1.1, 7.7, and 8.3 Hz, 2H), 3.24 (s,
H), 3.08 (t, J = 6.9 Hz, 4H), 2.14 (qt, J = 6.9 Hz, 4H).
mixture had been stirred at the temperature for 2.5 h
before 2-picolylamine (44.1 mL, 428 mmol) was loaded
and then was allowed to warm to room temperature with
stirring overnight. The solvent was evaporated in vacuo
and the residue was partitioned into AcOEt (300 mL)
IR (KBr): 3074, 3044, 3024, 3009, 2959, 2941, 2893, 2882,
2
1
8
866, 1697, 1603, 1483, 1442, 1421, 1406, 1366, 1333,
315, 1290, 1227, 1188, 1151, 1113, 1099, 991, 972, 881,
60, 800, 787, 748, 718, 698, 646, 604, 577, 536,
and H O (200 mL). After phase separation, the aqueous
2
ꢀ
1
5
13 cm . Anal. Calc. for C H O S : C, 51.81; H, 4.58.
layer was extracted with AcOEt (2 · 300 mL). The com-
bined organic layer was washed with brine, dried over
Na SO , and concentrated in vacuo. The residue was
1
9
20
8 2
Found: C, 51.73; H, 4.59%.
2
4
4
1
.2.3. (1RS,5SR)-1,5-Bis(2-methanesulfonyloxyphenyl)-
,5-pentanediol (4)
To a solution of 3 (107 g, 243 mmol) in dist. EtOH
chromatographed on silica gel (hexane/AcOEt = 4/6) to
give a 1:2 mixture of dl- and meso-5 (16.3 g, 70.1%) as col-
orless oil. Further purification by column chromatogra-
phy under the same conditions described above raised
the ratio of dl- and meso-isomers up to 69:31 (8.0 g,
34%). During this procedure, dl- and meso-5 were par-
(
1 L) at 0 ꢂC was added NaBH (20.0 g, 490 mmol) and
4
the mixture was stirred for 2 h at room temperature.
The reaction was quenched with conc. HCl (50 mL) fol-
1
lowed by extraction with CHCl (3 · 1 L). The combined
organic layer was washed with brine, dried over Na SO ,
and evaporated to give the crude product with a 1:1
ratio of dl- and meso-forms. The residue was purified
twice by column chromatography (SiO , hexane/AcOEt/
acetic acid = 4/6/0.1) to obtain dl-4 (53.6 g, 50%) as vis-
cous oil. H NMR (400 MHz): d 7.61–7.54 (m, 2H),
tially separated. H NMR (400 MHz): dl-5: d 8.37 (d,
3
J = 4.9 Hz, 1H), 7.91–7.89 (m, 2H), 7.63 (ddd, J = 1.7,
7.5, and 7.6 Hz, 1H), 7.43 (br d, J = 7.6 Hz, 1H), 7.43–
7.23 (m, 6H), 7.05 (dd, J = 4.9 and 7.5 Hz, 1H), 4.89
(dd, J = 4.9 and 6.4 Hz, 2H), 3.73 and 3.52 (ABq,
J = 6.2 Hz, 2H), 2.93 (s, 6H), 2.16 and 1.86 (ABm, 4H),
1.73 (m, 2H). meso-5: d 8.22 (br d, 1H), 7.83 (br d,
J = 6.8 Hz, 2H), 7.40–7.25 (br dd, J = 7.6 Hz, 2H), 7.24
(d, J = 2.4 Hz, 1H), 7.20–7.12 (m, 4H), 6.88 (br dd,
2
4
2
1
7
.39–7.24 (m, 6H), 5.04 (m, 2H), 3.24 (s, 6H), 2.43 (br
s, 2H), 1.94 and 1.79 (ABm, 4H), 1.52 (m, 2H). IR

T. Okamatsu et al. / Journal of Organometallic Chemistry 692 (2007) 645–653
651
J = 5.2 and 7.6 Hz, 1H), 6.79 (d, J = 8.0 Hz, 1H), 4.26 (br
d, J = 8.8 Hz, 2H), 3.54 (s, 2H), 3.25 (s, 6H), 1.97 and
J = 4.8 Hz, 1H), 3.72 (br m, 1H), 2.56–2.27 (br m, 2H),
2.18–1.96 (br m, 2H), 182–1.52 (br m, 2H), 1.48 (d,
J = 6.0 Hz, 3H), 1.45 (d, J = 6.0 Hz, 3H), 0.48 (d,
J = 6.0 Hz, 3H), 0.38 (d, J = 6.0 Hz, 3H).
1
6
.85 (ABm, 2H), 1.75-1.52 (m, 2H). To a solution of a
9:31 mixture of dl- and meso-5 (8.00 g, 15.5 mmol)in
MeOH (300 mL) and 1,4-dioxane (75 mL) was added
aq. KOH (3 M, 300 mL) and the mixture was stirred at
4.3.2. [Ti L (l-O) ]
3
3
3
5
0 ꢂC overnight. The reaction mixture was neutralized
Yellow single crystals of [Ti L (l-O) ] ꢁ 4CDCl (7) suit-
3
3
3
3
with conc. HCl and extracted with AcOEt (3 · 600 mL).
The combined organic layer was washed with brine, dried
over Na SO , and concentrated in vacuo. The residue was
chromatographed on silica gel with a 4:1 mixture of hex-
ane and AcOEt as eluent to afford dl-1 (3.6 g, 64%) as col-
orless crystals and meso-1 (1.6 g, 30%) as white powder.
Recrystallization of dl-1 from AcOEt gave single crystals
of suitable seize, one of which was submitted to X-ray
analysis to define its relative stereochemistry. dl-1: Mp
able for X-ray crystallography grew up from a solution of 6
in CDCl upon standing at room temperature. IR (KBr):
3
3423, 3059, 2951, 2868, 1593, 1481, 1447, 1304, 1283,
1153, 1111, 1047, 1030, 922, 800, 770, 735, 660,
2
4
ꢀ1
606 cm . Anal. Calc. for C H N O Ti Æ 0.6CDCl : C,
6
9
66
6
9
3
3
62.42; H, 5.06; N, 6.28. Found: C, 62.40; H, 5.23; N,
6.47%. This compound was hardly dissolved in common
organic solvents so that spectroscopic analyses conducted
for the solution of 7 were not applied.
2
05–206 ꢂC.
4.4. X-ray crystallographic data for dl-1
4.2.6. (2R,6R)-2,6-Bis(2-hydroxyphenyl)-1-
pyridylmethylpiperadine {(R,R)-1}
C H N O , M = 360.45, monoclinic, space group P2 /
2
3
24
2
2
1
˚
0
˚
˚
A mixture of dl-1 (1.20 g, 3.30 mmol) and (R,R)-O,O -
dibenzoyltartaric acid (1.19 g, 3.30 mmol) was dissolved
in AcOEt (600 mL) and the solution was allowed to stand
at room temperature overnight. The salt precipitated was
collected by suction filtration and dissolved in a two-phase
n, a = 14.2686(10) A, b = 7.8428(6) A, c = 16.4607(16) A,
3
˚
b = 94.007(4)ꢂ, V = 1837.5(3) A , T = ꢀ90 ꢂC, Z = 4,
3
ꢀ1
D = 0.1303 g/cm , l(Mo-Ka) = 0.834 cm , R = 0.0798
c
1
[I > 2rI], Rw = 0.2152 (all data) for 4152 reflections and
2
247 variables, GOF = 0.928, residual electron density
ꢀ
3
˚
mixture of AcOEt (300 mL) and satd. NaHCO (200 mL).
0.30/ꢀ0.27 e A , programs: SIR97 [25] and SHELXL-97 [26]
linked to CrystalStructure [27,28] crystallographic software
package. The ORTEP diagram in Fig. 3 was drawn by
Ortep-3 for Windows [29]. Full listings of the atomic coor-
dinates, bond lengths and angles have been deposited with
Cambridge Crystallographic Data as supplementary publi-
cation no. CCDC 603209.
3
The organic layer was evaporated to afford an enantio-
enriched free base of 1 (650 mg, 80% ee), which was recrys-
tallized from AcOEt (200 mL) to obtain optically pure 1
2
D
5
(
550 mg, 46%). ½aꢂ +78.8 (c 0.1, CHCl ). Mp 205–
3
1
2
7
6
06 ꢂC. H NMR (400 MHz): d 8.62 (d, J = 5.1 Hz, 1H),
.65 (ddd, J = 1.7, 7.6, and 7.8 Hz, 1H), 7.52–6.50 (br s,
H) 7.23 (dd, J = 5.2 and 7.2 Hz, 1H), 7.05 (d,
J = 8.0 Hz, 1H), 6.82 (dd, J = 7.2 and 8.6 Hz, 2H), 4.64–
4.5. X-ray crystallographic data for 7
4
2
1
1
.22 (br s, 2H), 4.28 and 3.96 (ABq, J = 17.6 Hz, 2H),
.45–1.80 (br m, 6H). IR (KBr): 3038, 2941, 2868, 1599,
578, 1585, 1487, 1375, 1354, 1277, 1236, 1204, 1184,
C H D N O Ti Cl ,
M = 1928.26,
monoclinic,
7
0
66
4
6
9
3
12
˚
˚
space group P2 , a = 13.2185(5) A, b = 21.5572(9) A,
1
ꢀ
1
3
˚
˚
V = 3912.1(3) A ,
153, 1097, 1082, 1045, 1011, 972, 926, 847, 752 cm
.
c = 13.7694(5) A,
b = 94.3930(8)ꢂ,
3
Anal. Calc. for C H N O : C, 76.64; H, 6.71; N, 7.77.
Found: C, 76.46; H, 6.73; N, 7.74%.
T = ꢀ90 ꢂC, Z = 2, D = 1.450 g/cm , l(Mo-Ka) =
2
3
24
2
2
c
ꢀ
1
7.650 cm , R = 0.0803 [I > 2rI], Rw = 0.1988 (all data)
1 2
for 17,153 reflections and 931 variables, GOF = 0.928,
ꢀ
3
˚
4
.3. Preparation of titanium(IV) complexes of (R,R)-1
residual electron density 0.80/ꢀ0.72 e A , Flack param-
eter = 0.006, programs: SIR97 [25] and SHELXL-97 [26]
linked to CrystalStructure [27,28] crystallographic soft-
ware package. The ORTEP diagram in Fig. 3 was drawn
by Ortep-3 for Windows [29]. Full listings of the atomic
coordinates, bond lengths and angles have been depos-
ited with Cambridge Crystallographic Data Centre as
supplementary publication no. CCDC 603208.
i
.3.1. [TiL(O Pr) ] (L = diphenolato anion of (R,R)-1)
4
2
(
6)
To a solution of (R,R)-1 (36 mg, 0.10 mmol) in anhy-
i
drous CH Cl (1 mL) was added Ti(O Pr)4 (30 lL,
0
ture for 1 h under nitrogen atmosphere. The solvent was
2
2
.10 mmol) and the mixture was stirred at room tempera-
evaporated in vacuo to dryness to give 6 (52 mg, quantita-
1
tive) as yellow solid. H NMR (400 MHz): d 9.29 (br d,
Acknowledgement
J = 8.0 Hz, 1H), 7.77 (dd, J = 7.6 and 8.0 Hz, 1H), 7.43–
7
.32 (m, 2H), 7.28 (d, J = 8.0 Hz, 1H), 7.16 (dd, J = 7.2
This work was supported by Grant-in-Aid for Scien-
tific Research on Priority Areas (No. 14078101, ‘‘Reac-
tion Control of Dynamic Complexes’’) from Ministry
of Education, Culture, Sports, Science and Technology,
Japan.
and 7.6 Hz, 1H), 7.10 (d, J = 8.0 Hz, 1H), 7.03 (dd,
J = 6.8 and 8.0 Hz, 1H), 6.76 (d, J = 7.6 Hz, 1H), 6.71–
6
.64 (m, 3H), 5.08 (br m, 1H), 4.62 and 4.34 (ABq,
J = 14.8 Hz, 2H), 4.46 (d, J = 9.9 Hz, 1H), 3.82 (d,

652
T. Okamatsu et al. / Journal of Organometallic Chemistry 692 (2007) 645–653
References
(b) Z. Dai, G. Proni, D. Mancheno, S. Karimi, N. Berova, J.W.
Canary, J. Am. Chem. Soc. 126 (2004) 11760;
c) Z. Dai, X. Xu, J.W. Canary, Chirality 17 (2005) S227.
12] For reviews regarding asymmetric catalyses by metal complexes with
-symmetric chiral tripodal ligands, see: C. Moberg, Angew. Chem.,
(
[
1] J.A. McCleverty, T.J. Meyer, L. QueJr., W.B. Tolman (Eds.),
Comprehensive Coordination Chemistry II, vol. 8, Elsevier Perg-
amon, Amsterdam, 2004.
[
C
3
Int. Ed. 37 (1998) 248;
See also: S.P. Hajela, A.R. Johnson, J. Xu, C.J. Sunderland,
S.M. Cohen, D.L. Caulder, K.N. Raymond, Inorg. Chem. 40
[
[
[
2] H. Kawaguchi, T. Matsuo, J. Organomet. Chem. 689 (2004)
4
228.
3] L.F. Szczepura, L.M. Witham, K.J. Takeuchi, Coord. Chem. Rev.
74 (1998) 5.
(
2001) 3208.
1
[
13] (a) B. Hammes, D. Ramos-Maldonado, G.P.A. Yap, P.A. Glenn, L.
Liable-Sands, A.L. Rheingold, V.G.J. Young, A.S. Borovik, Inorg.
Chem. 36 (1997) 3210;
4] (a) C.J. Hinshaw, G. Peng, R. Singh, J.T. Spence, J.H. Enemark, M.
Bruck, J. Kristofzski, S.L. Merbs, R.B. Ortega, P.A. Wexler, Inorg.
Chem. 28 (1989) 4483;
(
(
(
(
(
b) J.M. Castagnetto, X. Xu, N.D. Berova, J.W. Canary, Chirality 9
1997) 616;
c) J.M. Castagnetto, J.W. Canary, Chem. Commun. (1998) 203;
d) S. Zahn, J.W. Canary, Angew. Chem., Int. Ed. 37 (1998) 305;
e) J.W. Canary, Y. Wang, R. Roy Jr., L. Que Jr., H. Miyake, Inorg.
(
b) I. Vencato, A. Neves, A.S. Ceccato, A. Horn Jr., Acta Crystal-
logr., Sect. C: Cryst. Struct. Commun. C52 (1996) 949;
c) D. Zurita, C. Scheer, J.-L. Pierre, E. Saint-Aman, J. Chem. Soc.,
Dalton Trans. (1996) 4331;
d) S. Menage, G. Gellon, J.-L. Pierre, D. Zurita, E. Saint-Aman,
Bull. Soc. Chim. Fr. 134 (1997) 785;
e) Y.-L. Wong, Y. Yan, E.S.H. Chan, Q. Yang, T.C.W. Mak,
D.K.P. Ng, J. Chem. Soc., Dalton Trans. (1998) 3057;
f) M. Hirotsu, M. Kojima, W. Mori, Y. Yoshikawa, Bull. Chem.
Soc. Jpn. 71 (1998) 2873;
g) A. Abrahams, A.R. Cowley, T.I.A. Gerber, C. Imrie, P. Mayer,
J. Coord. Chem. 56 (2003) 1299;
h) A. Mondal, S. Sarkar, D. Chopra, T.N. Row, R. Guru, K. Kajal,
(
(
Synth. 32 (1998) 70;
f) J.W. Canary, C.S. Allen, J.M. Castagnetto, Y.-H. Chiu, P.J.
Toscano, Y. Wang, Inorg. Chem. 37 (1998) 6255;
(
(
(
(
g) S. Zahn, J.W. Canary, Org. Lett. 1 (1999) 861;
h) Y.-H. Chiu, O. Dos Santos, J.W. Canary, Tetrahedron 55 (1999)
(
1
2069;
(
(
(
i) S. Zahn, J.W. Canary, Science 288 (2000) 1404;
j) J.W. Canary, S. Zahn, Y.-H. Chiu, O. Dos Santos, J. Liu, L. Zhu,
(
Enantiomer 5 (2000) 397;
k) X. Xu, K.J. Maresca, D. Das, S. Zahn, J. Zubieta, J.W. Canary,
Chem. Eur. J. 8 (2002) 5679;
Dalton Trans. (2004) 3244.
5] (a) K. Kawasaki, S. Tsumura, T. Katsuki, Synlett (1995) 1245;
(
[
[
(
(
b) K. Kawasaki, T. Katsuki, Tetrahedron 53 (1997) 6337;
c) Y. Kohmura, K. Kawasaki, T. Katsuki, Synlett (1997) 1456.
(
(
(
(
l) Canary S. Zahn, J.W. Canary, J. Am. Chem. Soc. 124 (2002) 9204;
m) S.H. Barcena, A.E. Holmes, S. Zahn, J.W. Canary, Org. Lett. 5
2003) 709;
6] (a) M.C. Keyes, W.B. Tolman, Adv. Catal. Proc. 2 (1997) 189;
(
(
b) C. Moberg, Angew. Chem., Int. Ed. 37 (1998) 248;
c) M. Mikulas, K. Ruck-Braun, Org. Synth. Highlights IV (2000)
n) T. Yamada, S. Shinoda, H. Sugimoto, J.-I. Uenishi, H. Tsukube,
Inorg. Chem. 42 (2003) 7932–7937;
187;
(
(
(
o) H. Tsukube, T. Yamada, S. Shinoda, J. Alloys Compd. 374
2004) 40;
p) H.S. Barcena, B.M. Liu, V. Michael, J.W. Canary, Inorg. Chem.
(
(
d) H.A. McManus, P.J. Guiry, Chem. Rev. 104 (2004) 4151;
e) J. Zhou, Y. Tang, Chem. Soc. Rev. 34 (2005) 664.
[
[
7] (a) P.D. Knight, P. Scott, Coord. Chem. Rev. 242 (2003) 125;
4
4 (2005) 7652;
q) J. Zhang, K. Siu, C.H. Lin, J.W. Canary, New J. Chem. 29 (2005)
147;
r) A.E. Holmes, S.A. Simpson, J.W. Canary, Monatshefte Chem.
36 (2005) 461;
s) M. Royzen, Z. Dai, J.W. Canary, J. Am. Chem. Soc. 127 (2005)
612.
14] M. Cornia, L. Merlini, A. Zanarotti, Gazz. Chim. Itali. 107 (1977)
99.
(
(
(
b) C.-M. Che, J.-S. Huang, Coord. Chem. Rev. 242 (2003) 97;
c) T. Katsuki, Synlett (2003) 281;
d) T. Katsuki, Chem. Soc. Rev. 33 (2004) 437.
(
1
(
1
(
1
8] (a) For the recent progress on asymmetric reactions catalyzed by
chiral cis-b metal complexes, see: A. Watanabe, T. Uchida, R. Irie,
T. Katsuki, Proc. Natl. Acad. Sci. U.S.A. 101 (2004) 5737;
(
b) P.D. Knight, I. Munslow, P.N. O’Shaughnessy, P. Scott, Chem.
Commun. (2004) 894;
c) Y.N. Belokon, M. North, V.I. Maleev, N.V. Voskoboev, M.A.
[
[
[
2
(
15] S. Pache, C. Botuha, R. Franz, E.P. Kundig, J. Einhorn, Helv. Chim.
Acta 83 (2000) 2436.
16] S. Yonezawa, T. Komurasaki, K. Kawada, T. Tsuri, M. Fuji, A.
Kugimiya, N. Haga, S. Mitsumori, M. Inagaki, T. Nakatani, Y.
Tamura, S. Takechi, T. Taishi, M. Ohtani, J. Org. Chem. 63 (1998)
Moskalenko, A.S. Peregudov, A.V. Dmitriev, N.S. Ikonnikov, H.B.
Kagan, Angew. Chem., Int. Ed. 43 (2004) 4085;
(d) P.N. O’Shaughnessy, K.M. Gillespie, P.D. Knight, I.J. Munslow,
P. Scott, Dalton Trans. (2004) 2251;
(
(
e) B. Saito, T. Katsuki, Angew. Chem., Int. Ed. 44 (2005) 4600;
f) K. Matsumoto, Y. Sawada, B. Saito, K. Sakai, T. Katsuki,
5
831.
[
17] Accordingly, it is implied that a helical chirality (C, clockwise) [30] is
induced around the piperidyl nitrogen atom of (R,R)-1 and the
tertiary amine site is set deep inside the chiral screw created by the
three aromatic side arms. This structural feature has prompted us to
examine the potentiality of (R,R)-1 as a chiral base catalyst in
asymmetric methanolytic desymmetrization of cyclic meso-anhydrides
to hemiesters, demonstrating a good level of enantioselectivities (up to
Angew. Chem., Int. Ed. 44 (2005) 4935;
g) Y. Sawada, K. Matsumoto, S. Kondo, H. Watanabe, T. Ozawa,
K. Suzuki, B. Saito, T. Katsuki, Angew. Chem., Int. Ed. 45 (2006)
478.
(
3
[
9] (a) R. Burth, A. Stange, M. Schaefer, H. Vahrenkamp, Eur. J. Inorg.
Chem. 37 (1998) 1759;
(
3
(
1
b) U. Knof, A. Von Zelewsky, Angew. Chem., Int. Ed. 38 (1999)
03;
c) N. Niklas, O. Walter, R. Alsfasser, Eur. J. Inorg. Chem. 39 (2000)
723.
7
8% ee) with catalyst loadings unprecedentedly as low as 1 mol% [31].
[
18] The view is determined by the ligating atom with the highest priority
ranking to the trans-ligating atom with a lower priority through the
metal center. In order to avoid the inconvenience that the chirality
description varies with the priority rankings of the ancillary ligating
atoms irrespective to the absolute configuration, herein we take only
the ligating atoms in the ligand into account and the l-O atoms are
not concerned to define the configuration at the metal center.
[
[
10] A. von Zelewsky, Stereochemistry of Coordination Compounds, John
Wiley & Sons, Chichester, 1996.
11] (a) Analogous optically active tripodal tertiary amines, 2,6-trans-
1,2,6-trisubstituted piperidine with tris(pyridine) pendants or its
quinoline variant were reported and used for studies on asymmetric
recognition and metal sensing. Z. Dai, X. Xu, J.W. Canary, Chem.
Commun. (2002) 1414;
[
19] (a) M. Merkel, F.K. Muller, B. Krebs, Inorg. Chim. Acta 337 (2002)
3
08;

T. Okamatsu et al. / Journal of Organometallic Chemistry 692 (2007) 645–653
653
(
(
(
b) H. Adams, D. Bradshaw, D.E. Fenton, Inorg. Chem. Commun. 5
2002) 12;
c) T. Toupance, S.R. Dubberley, N.H. Rees, B.R. Tyrrell, P.
(o) J.I. Amor, T. Cuenca, M. Galakhov, P. Gomez-Sal, A. Manzan-
ero, P. Royo, J. Organomet. Chem. 535 (1997) 155;
(p) M. Bjoergvinsson, S. Halldorsson, I. Arnason, J. Magull, D.
Fenske, J. Organomet. Chem. 544 (1997) 207;
(q) R. Andres, M. Galakhov, M.P. Gomez-Sal, A. Martin, M. Mena,
C. Santamaria, Chem. Eur. J. 4 (1998) 1206;
(r) M. Galakhov, P. Gomez-Sal, A. Martin, M. Mena, C. Yelamos,
Eur. J. Inorg. Chem. (1998) 1319;
Mountford, Organometallics 21 (2002) 1367;
d) N. Reddig, D. Pursche, B. Krebs, A. Rompel, Inorg. Chim. Acta
57 (2004) 2703;
e) C.L. Boyd, T. Toupance, B.R. Tyrrell, B.D. Ward, C.R. Wilson,
A.R. Cowley, P. Mountford, Organometallics 24 (2005) 309;
f) R. Jovito, A. Neves, A.J. Bortoluzzi, M. Lanznaster, V. Drago,
(
3
(
(
(s) , For other examples, see:M. Sato, A. Mori, M. Aizawa, Jpn.
Kokai Tokkyo Koho (1989) 13;
W. Haase, Inorg. Chem. Commun. 8 (2005) 323.
[
20] (a) A. Neves, M.A. de Brito, I. Vencato, V. Drago, K. Griesar, W.
Haase, Y.P. Mascarenhas, Inorg. Chim. Acta 214 (1993) 5;
(t) M. Sato, A. Mori, M. Aizawa, Jpn. Kokai Tokkyo Koho (1989)
13;
(
b) B. Krebs, K. Schepers, B. Bremer, G. Henkel, E. Althaus, W.
Muller-Warmuth, K. Griesar, W. Haase, Inorg. Chem. 33 (1994) 1907;
c) M.A. de Brito, A. Neves, I. Vencato, C. Zucco, V. Drago, K.
Griesar, W. Haase, J. Braz. Chem. Soc. 8 (1997) 443;
d) I.M. Atkinson, Jy.D. Chartres, G.W. Everett, X.-K. Ji, L.F.
(u) M. Aizawa, A. Mori, M. Sato, Jpn. Kokai Tokkyo Koho (1989)
9;
(v) A. Voigt, R. Murugavel, M.L. Montero, H. Wessel, F.-Q. Liu,
H.W. Roesky, I. Uson, T. Albers, E. Parisini, Angew. Chem., Int.
Ed. 36 (1997) 1001;
(
(
Lindoy, O.A. Matthews, G.V. Meehan, B.W. Skelton, G. Wei, A.H.
White, J. Chem. Soc., Dalton Trans. (2000) 1191;
(w) N.M. Laptash, M.A. Fedotov, I.G. Maslennikova, J. Struct.
Chem. 45 (2004).
(
(
(
(
2
(
e) H. Adams, D. Bradshaw, D.E. Fenton, Supramol. Chem. 13 (2001) 513;
f) H. Adams, D. Bradshaw, D.E. Fenton, J. Chem. Soc., Dalton Trans.
2001) 3407;
g) E.Y. Tshuva, I. Goldberg, M. Kol, Z. Goldschmidt, Organometallics
0 (2001) 3017;
h) P. Karsten, A. Neves, A.J. Bortoluzzi, M. Lanznaster, V. Drago, Inorg.
Chem. 41 (2002) 4624;
i) M. Lanznaster, A. Neves, A.J. Bortoluzzi, B. Szpoganicz, E. Schwingel,
Inorg. Chem. 41 (2002) 5641;
j) P. Karsten, A. Neves, A.J. Bortoluzzi, J. Strahle, C. Maichle-Mossmer,
Inorg. Chem. Commun. 5 (2002) 434;
k)M.E.G.Skinner,B.R.Tyrrell,B.D.Ward,P.Mountford,J.Organomet.
Chem. 647 (2002) 145;
l) S.C. Batista, A. Neves, A.J. Bortoluzzi, I. Vencato, R.A. Peralta, B.
[22] (a) B. Saito, T. Katsuki, Tetrahedron Lett. 42 (2001) 3873;
(b) B. Saito, T. Katsuki, Tetrahedron Lett. 42 (2001) 8333;
(c) T. Tanaka, B. Saito, T. Katsuki, Tetrahedron Lett. 43 (2002)
3259;
(d) B. Saito, T. Katsuki, Chirality 15 (2003) 24.
[23] C.F. Huebner, P.L. Strachan, E.M. Donoghue, N. Cahoon, L.
Dorfman, R. Margerison, E. Wenkert, J. Org. Chem. 32 (1967)
1126.
[24] Y. Peter, E. Philip, J. Am. Chem. Soc. 82 (1960) 4436.
[25] A. Altomare, M. Burla, M. Camalli, G. Cascarano, C. Giacovazzo,
A. Guagliardi, A. Moliterni, G. Polidori, R. Spagna, J. Appl. Cryst.
32 (1999) 115.
(
(
(
[26] Sheldrick, G. M. SHELX97; 1997.
(
[27] CrystalStructure 3.7.0: Crystal Structure Analysis Package, Rigaku
and Rigaku/MSC (2000–2005). 9009 New Trails Dr. The Woodlands,
TX 77381, USA.
Szpoganicz, V.V.E. Aires, H. Terenzi, P.C. Severino, Inorg. Chem.
Commun. 6 (2003) 1161;
(
3
m) H. Adams, D.E. Fenton, P.E. McHugh, Inorg. Chim. Acta 357 (2004)
641.
21] (a) H. Koepf, S. Grabowski, R. Voigtlaender, J. Organomet. Chem.
16 (1981) 185;
b) S.G. Blanco, S.M.P. Gomez, C.S. Martinez, M. Mena, P. Royo,
R. Serrano, J. Chem. Soc., Chem. Commun. (1986) 1572;
c) L.M. Babcock, V.W. Day, W.G. Klemperer, J. Chem. Soc.,
Chem. Commun. (1987) 858;
d) R. Serrano, J.C. Flores, P. Royo, M. Mena, M.A. Pellinghelli, A.
Tiripicchio, Organometallics 8 (1989) 1404;
[28] D.J. Watkin, C.K. Prout, J.R. Carruthers, P.W. Betteridge, CRYS-
TALS Issue 10, Chemical Crystallography Laboratory, Oxford, UK,
1996.
[29] L.J. Farrugia, J. Appl. Cryst. 30 (1990) 565.
[30] I. Katsuki, Y. Motoda, Y. Sunatsuki, N. Matsumoto, T. Nakashima,
M. Kojima, J. Am. Chem. Soc. 124 (2002) 629.
[31] (a) J. Hiratake, Y. Yamamoto, J. Oda, J. Chem. Soc., Chem.
Communi (1985) 1717;
[
2
(
(
(
(b) J. Hiratake, M. Inagaki, Y. Yamamoto, J. Oda, J. Chem. Soc.,
Perkin Trans. 1 (1987) 1053;
(
(
(
(
e) L.M. Babcock, W.G. Klemperer, Inorg. Chem. 28 (1989) 2003;
f) S.I. Troyanov, V. Varga, K. Mach, J. Organomet. Chem. 402
1991) 201;
(c) R.A. Aitken, J. Gopal, J.A. Hirst, J. Chem. Soc., Chem. Commun.
(1998) 632;
(d) C. Bolm, A. Gerlach, C.L. Dinter, Synlett (1999) 195;
(e) Y. Chen, S.-K. Tian, L. Deng, J. Am. Chem. Soc. 122 (2000)
9542;
(f) C. Bolm, I. Schiffers, C.L. Dinter, A. Gerlach, J. Org. Chem. 65
(2000) 6984;
(g) C. Bolm, I. Atodiresei, I. Schiffers, M. Kanai, M. Shibasaki, Org.
Synth. 82 (2005) 120;
(h) H.S. Kim, Y.-M. Song, J.S. Choi, J.W. Yang, H. Han,
Tetrahedron 60 (2004) 12051;
(i) Y.-M. Song, J.S. Choi, J.W. Yang, H. Han, Tetrahedron Lett. 45
(2004) 3301;
g) S.I. Troyanov, V.B. Rybakov, V. Varga, P. Sedmera, K. Mach,
Metalloorg. Khim. 4 (1991) 1004;
h) T. Carofiglio, C. Floriani, A. Sgamellotti, M. Rosi, A. Chiesi-
Villa, C. Rizzoli, J. Chem. Soc., Dalton Trans. (1992) 1081;
i) A. Martin, M. Mena, C. Yelamos, R. Serrano, P.R. Raithby, J.
Organomet. Chem. 467 (1994) 79;
j) R. Andres, M.V. Galakhov, A. Martin, M. Mena, C. Santamaria,
Organometallics 13 (1994) 2159;
k) R. Andres, M. Galakhov, A. Martin, M. Mena, C. Santamaria,
J. Chem. Soc., Chem. Commun. (1995) 551;
(
(
(
(
(
(
(
l) A. Abarca, A. Martin, M. Mena, P.R. Raithby, Inorg. Chem. 34
1995) 5437;
m) P. Gomez-Sal, A. Martin, M. Mena, C. Yelamos, Inorg. Chem.
(j) F. Bigi, S. Carloni, R. Maggi, A. Mazzacani, G. Sartori, G.
Tanzi, J. Mol. Catal. A: Chem. 182–183 (2002) 533;
(k) Y. Chen, S.-K. Tian, L. Deng, J. Am. Chem. Soc. 122 (2000)
9542;
(l) Y. Uozumi, K. Yasoshima, T. Miyachi, S.-I. Nagai, Tetrahedron
Lett. 42 (2001) 411.
3
5 (1996) 242;
n) R. Andres, M. Galakhov, M.P. Gomez-Sal, A. Martin, M. Mena,
C. Santamaria, J. Organomet. Chem. 526 (1996) 135;
(