P-chirogenic phosphines supported by calix[4]arene: New Insight into palladium-catalyzed asymmetric allylic substitution

Article abstract of DOI:10.1021/om400229p

The first P-chirogenic mono- and diphosphine ligands supported on the upper rim of a calix[4]arene moiety were synthesized using the ephedrine methodology. The lithiated calix[4]arene mono- and dianions both react with the oxazaphospholidine-borane, prepared from ephedrine, to afford regio- and stereoselectively the corresponding calix[4]arenyl aminophosphine-boranes, by cleavage of the heterocyclic ring at the P-O bond position. Subsequent reactions with HCl and then organolithium reagent and finally decomplexation with DABCO lead to the corresponding calix[4]arenyl mono- or diphosphines. Both enantiomers of the calix[4]arenyl phosphines were obtained either by using (+)- or (-)-ephedrine or by changing the addition order of the organolithium reagents during the synthesis. The enantiomeric excesses of the phosphines were determined either by HPLC on a chiral column of their borane complexes or by ³¹P NMR in the presence of a chiral palladium complex. The absolute configurations of the mono- and diphosphinocalix[4]arenes were assigned by X-ray analysis of their crystalline borane complexes. The P-chirogenic calix[4]arenyl phosphines were tested for asymmetric palladium-catalyzed allylic substitution of (E)-1,3-diphenylprop-2-en-1-yl acetate, by dimethyl malonate or benzylamine. When the bis-methylphenylphosphino calix[4]arene was used, the allylic products were obtained with 82% and 79% ee, respectively. In both cases, the use of a diphosphine affords better results than using 2 equivalents of monophosphine. Despite the C₂ symmetry of the P-chirogenic diphosphine calix[4]arene ligand, computer modeling of the corresponding Pd(allyl) complex shows a clear dissymmetry of the LUMO, which is in good agreement with a complexed η¹-allyl moiety and with the regio- and enantioselectivity of the Pd-catalyzed allylations.

Full text of DOI:10.1021/om400229p

Article
pubs.acs.org/Organometallics
P‑Chirogenic Phosphines Supported by Calix[4]arene: New Insight
into Palladium-Catalyzed Asymmetric Allylic Substitution
Naima Khiri-Meribout,†,§ Etienne Bertrand,†,‡ Jerome Bayardon,† Marie-Joelle Eymin,† Yoann Rousselin,†
́
̂
̈
Helene Cattey,† Daniel Fortin,‡ Pierre D. Harvey,*,‡ and Sylvain Juge*,†
́
̀
́
†Institut de Chimie Molec
21078 Dijon Cedex, France
‡Dep
artement de Chimie, Universite
́
ulaire de l’Universite
́
de Bourgogne, Ster
́
eo
́
chIM, UMR CNRS 6302, 9 avenue Alain Savary BP 47870,
́
́
de Sherbrooke, Sherbrooke, Queb
́
ec, Canada J1K2R1
S
* Supporting Information
ABSTRACT: The first P-chirogenic mono- and diphosphine ligands supported on the upper rim of a calix[4]arene moiety were
synthesized using the ephedrine methodology. The lithiated calix[4]arene mono- and dianions both react with the
oxazaphospholidine−borane, prepared from ephedrine, to afford regio- and stereoselectively the corresponding calix[4]arenyl
aminophosphine−boranes, by cleavage of the heterocyclic ring at the P−O bond position. Subsequent reactions with HCl and
then organolithium reagent and finally decomplexation with DABCO lead to the corresponding calix[4]arenyl mono- or
diphosphines. Both enantiomers of the calix[4]arenyl phosphines were obtained either by using (+)- or (−)-ephedrine or by
changing the addition order of the organolithium reagents during the synthesis. The enantiomeric excesses of the phosphines
were determined either by HPLC on a chiral column of their borane complexes or by 31P NMR in the presence of a chiral
palladium complex. The absolute configurations of the mono- and diphosphinocalix[4]arenes were assigned by X-ray analysis of
their crystalline borane complexes. The P-chirogenic calix[4]arenyl phosphines were tested for asymmetric palladium-catalyzed
allylic substitution of (E)-1,3-diphenylprop-2-en-1-yl acetate, by dimethyl malonate or benzylamine. When the bis-
methylphenylphosphino calix[4]arene was used, the allylic products were obtained with 82% and 79% ee, respectively. In
both cases, the use of a diphosphine affords better results than using 2 equivalents of monophosphine. Despite the C2 symmetry
of the P-chirogenic diphosphine calix[4]arene ligand, computer modeling of the corresponding Pd(allyl) complex shows a clear
dissymmetry of the LUMO, which is in good agreement with a complexed η1-allyl moiety and with the regio- and
enantioselectivity of the Pd-catalyzed allylations.
reactions with various C−Y (Y = H, C, N, B) bond
formation.6−8
INTRODUCTION
■
Chiral phosphorus ligands play a central role in transition-
metal-catalyzed asymmetric reactions, and these processes are
now commonly used for the enantioselective synthesis of chiral
substances, including those that are industrially commercial-
ized.1,2 Recently, among the numerous types of reported chiral
ligands described, phosphines bearing the chirality on the P
center (P-chirogenic) have received a growing interest, due to
the development of efficient methods for their stereoselective
synthesis.3 The interest in these ligands is due to the P-chirality
that is positioned in close proximity to the reaction center,
which favors a more sterically and electronically defined
architecture about the metal atom.4,5 So far, many P-chirogenic
ligands allow high enantioselectivities in catalyzed asymmetric
Over the past decades, calix[4]arene-containing phosphine
ligands have led to an extremely rich coordination chemistry
and have been extensively studied in transition-metal
catalysis.9,10 The use of a phosphorus ligand containing a
calix[4]arene moiety in catalysis has been more recently
recognized for its potential applications and has already been
evaluated in olefin hydroformylation,11 oligomerization and
polymerization reactions,12 hydrogenation,13 carbon−carbon
bond forming reactions,14 and allylic alkylation.15 So far, many
Received: March 18, 2013
© XXXX American Chemical Society
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Scheme 1. Synthesis of the P-Chirogenic Calix[4]arenyl Monophosphines 5
Figure 1. ORTEP19 view of the P-chirogenic monophosphine borane (S)-4c. Thermal ellipsoids are shown at the 50% probability level. The
hydrogen and disordered atoms have been omitted for clarity. Selected bond lengths (Å) and angles (deg): P1−B1 = 1.909(7), P1−C1 = 1.803(5),
P1−C41 = 1.827(6), P1−C47 = 1.806(6); C1−P1−C47 = 105.3(2), C1−P1−C41 = 104.9(3), C47−P1−C41 = 105.0(3), C1−P1−B1 = 114.9(3),
C47−P1−B1 = 115.2(3), C41−P1−B1 = 110.5(3).
chiral organophosphorus ligands derived from calix[4]arene are
known,9−15 but only few asymmetric catalysis have been
described.13 Recently, we reported the first synthesis of a P-
chirogenic AMP*P ligand with a calix[4]arenyl substituent on
the aminophosphine moiety and its uses in rhodium-catalyzed
asymmetric hydrogenation reactions.16a The preparation of
chiral calix[4]arene-based phosphorus ligands is of continuing
interest, and we report the first stereoselective synthesis of P-
chirogenic mono- and diphosphines supported on the upper
rim of a calix[4]arene moiety and their use as ligands in
palladium-catalyzed asymmetric allylic substitution.
prepared respectively from (−)- or (+)-ephedrine (Scheme
1).17
The reaction of the complex (+)-1 with (25,26,27,28-
tetrapropoxycalix[4]aren-5-yl)lithium16b as the R1Li reagent
stereospecifically affords the aminophosphine−borane 2a (R1 =
CX) in 84% yield, by P−O bond cleavage and retention at the
P center (Scheme 1a). Evidence for the stereochemistry of the
ring-opening reaction has been provided by an X-ray structure
determination of the previously described P-chirogenic calix[4]-
arenyl aminophosphine−phosphinite (AMPP*) ligand, derived
from 2a.16 After acidolysis of the aminophosphine−borane 2a
with dry HCl, the resulting chlorophosphine−borane 3a
reacted with organolithium reagents to provide the correspond-
ing P-chirogenic monophosphine−boranes (S)-4a−c with
yields ranging from 46 to 62% (Scheme 1a). The enantiomeric
excesses of the phosphine−boranes 4a−c were determined by
HPLC on a chiral column, with 99% and 84% ee, respectively.
RESULTS AND DISCUSSION
■
The P-chirogenic calix[4]arenyl monophosphines 5a−c have
been synthesized according to the methodology starting from
the (+)- or (−)-oxazaphospholidine borane complex 1,
B
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Figure 2. ORTEP19 view of the P-chirogenic phosphine−borane (R)-4b. Thermal ellipsoids are shown at the 30% probability level. The hydrogen
and disordered atoms have been omitted for clarity. Selected bond lengths (Å) and angles (deg): C1−P1 = 1.808(3), C7−P1 = 1.820(3), C14−P1 =
1.812(3), P1−B1 = 1.893(4); C1−P1−C14 = 107.95(14), C1−P1−C7 = 108.84 (15), C14−P1−C7 = 106.12(14), C1−P1−B1 = 109.5(2), C14−
P1−B1 = 113.0(2), C7−P1−B1 = 111.23(17).
Scheme 2. Synthesis of the P-Chirogenic Calix[4]arene Diphosphines 9a−c
However, an analytically pure sample of the P-chirogenic
calix[4]arenyl phosphine−borane (S)-4c has been obtained as
single crystals by slow diffusion of methanol into dichloro-
methane, and its structure was established by X-ray analysis
(Figure 1). The crystallographic unit cell of the crystal contains
two independent molecules with similar conformations. Thus,
the X-ray structure of 4c shows the calix[4]arene moiety with a
flattened cone conformation, due to the presence of the
propoxy groups in the lower rim, and the ferrocenyl substituent
outside of the cavity. In addition, the structure proves the
absolute configuration (S) of the phosphorus atom, which is in
good agreement with the stereochemistry with inversion of
configuration previously established for the acidolysis with HCl
of aminophosphine−borane derivatives and for the stereo-
selective synthesis of P-chirogenic phosphine−boranes.17,18
It is worth noting that the synthesis of the phosphine−
borane enantiomers 4 can also be achieved from the starting
complex (−)-1, derived from (+)-ephedrine, by inverting the
introduction order of the lithium reagents during the synthesis
(Scheme 1b). Thus, subsequent reactions of the (−)-oxaza-
phospholidine−borane complex 1 with the o-anisyllithium
reagent, acidolysis with HCl, and then trapping of the resulting
chlorophosphine 3′b (R2 = o-An) with (calix[4]arenyl)lithium
(R1= CX) affords the phosphine−borane (R)-4b in 60% yield
and with 99% ee (Scheme 1b). The enantiomeric phosphine−
borane (R)-4b was thus obtained using this second strategy, but
starting from the complex (+)-1, derived from (−)-ephedrine
(Scheme 1a). A single crystal of (R)-4b has been obtained, and
its structure was established by X-ray analysis.
This structure exhibits a flattened cone conformation for the
calix[4]arene ring, notably due to the presence of the
phosphine−borane moiety on the upper ring, and the R
absolute configuration is established for the P center (Figure 2).
Finally, the decomplexation of phosphine−boranes 4a−c was
achieved with retention of configuration on the phosphorus
atom, upon heating with the 1,4-diazabicyclo[2.2.2]octane
C
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Figure 3. ORTEP19 representation of P-chirogenic diphosphine−diborane (S,S)-8c. Thermal ellipsoids are shown at the 50% probability level.
Selected bond lengths (Å) and angles (deg): P1−B1 = 1.914(5), C11−P1 = 1.831(4), C1−P1 = 1.799(5), C17−P1 = 1.818(4); C1−P1−C17 =
104.9(2), C17−P1−C11 = 103.8(2), C1−P1−B1 = 114.9(2), C17−P1−B1 = 115.2(2), C11−P1−B1 = 111.0(2).
Scheme 3. Synthesis of the P-Chirogenic Calix[4]arene Diphosphine (S,S)-8b from the Chlorophosphine−Borane (S)-3′b
(DABCO) in toluene at 50 °C. After a short filtration on
neutral alumina free uncoordinated P-chirogenic monophos-
phines 5a−c were obtained in yields >97% (Scheme 1).
Concurrently, the synthesis of P-chirogenic diphosphines
9a−c supported on the upper rim of a calix[4]arene moiety was
achieved according to a similar methodology as described above
for the monophosphines 5, but using the calix[4]arene
dilithium reagent 6 (Scheme 2).
Thus, the reaction of the (25,26,27,28-tetrapropoxycalix[4]-
arene)dilithium reagent 6 with 2 equiv of the starting complex
(+)-1 leads to the bis(aminophosphine)−borane product 7 in
73% yield, from ring opening of the heterocycle at the P−O
bond. After acidolysis of compound 7 with dry HCl in toluene,
the resulting bis(chlorophosphine)−borane intermediate reacts
with 2 equivalents of organolithium reagents to afford the
corresponding P-chirogenic diphosphine diboranes 8a−c in
43−46% isolated yields. Crystals of diphosphine−diborane 8c
suitable for X-ray structure analysis have been obtained from
methanol, and the X-ray structure is depicted in Figure 3.
Compound 8c crystallizes with two half molecules in its unit
cell, showing a clear C2 symmetry. Thus, the diphosphine−
diborane 8c crystallizes in the noncentrosymmetric C2 space
group, establishing the S,S absolute configuration for the P
center, supported by refinement of the Flack parameter.20
The P-chirogenic diphosphine−diborane 8b was also
synthesized according to a second strategy, which consists of
reacting 2 equiv of the chlorophosphine−borane (S)-3′b (R2 =
o-An), previously prepared from (−)-1, with the (25,26,27,28-
tetrapropoxycalix[4]arene)dilithium reagent 6 (Schemes 2 and
3). However, in this case the diphosphine−diborane 8b was
obtained with a lower yield with respect to the former synthetic
route (40%). This is, in fact, due to the formation of byproducts
such as the monophosphine−borane (S)-4b (25%) and the 17-
chlorocalix[4]arene phosphine−borane (S)-11 (25%) (Scheme
3). The formation of these compounds is explained either by
the protonation of the unreacted monanion 10 derived from
the monophosphine−borane or by metal−halogen exchange
with the chlorophosphine−borane 3′b (Scheme 3). We
previously described the reaction of a bulky organolithium
reagent with the chlorophosphine−borane 3′b, to prepare the
D
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corresponding P-chirogenic phosphide−borane lithium salt, by
metal halide exchange.3,17 The structure of the 17-
chlorocalix[4]arene phosphine−borane (S)-11 was confirmed
by X-ray analysis, after extracting crystals issued from a
recrystallization in a mixture of methanol and dichloromethane
(Figure 4).
Table 1. Results of Pd-Catalyzed Allylation of Dimethyl
Malonate in the Presence of P-Chirogenic Mono- and
a
Diphosphines 5a and 9a−c
b
cd
,
entry
ligand
base
solvent
conversn (%)
ee (%)
1
2
3
(S)-5a
BSA/KOAc
BSA/KOAc
BSA/KOAc
BSA/KOAc
BSA/LiOAc
BSA/NaOAc
BSA/KOAc
n-BuLi
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
THF
100
100
100
100
100
100
100
100
5
70
16
40
69
69
73
82
(S,S)-9a
(S,S)-9b
(S,S)-9c
(S,S)-9a
(S,S)-9a
(S,S)-9a
(S,S)-9a
e
4
5
6
f
7
f
8
a
Reaction conditions: 0.008 mmol of [Pd(η3-C3H5)Cl]2, 0.016 mmol
of ligand 9a−c (or 0.032 mmol 5a), 0.8 mmol of (E)-( )-1,3-
diphenylprop-2-en-1-yl acetate (13), 1.6 mmol of dimethyl malonate,
and 1.6 mmol of base (and a catalytic amount of acetate if necessary)
b
in 6 mL of dry solvent. Reaction times: 1−20 h. Conversion was
c
determined by 1H NMR of the crude mixture. Determined by HPLC
d
e
with a Chiralpak AD column. S absolute configuration. Ligand 9c
f
with 84% ee was used. The reaction was performed at 0 °C.
Table 2. Results of Pd-Catalyzed Allylation of Benzylamine
in the Presence of P-Chirogenic Mono- and Diphosphines
5a,b and 9a,b
Figure 4. ORTEP19 representation of the 17-chloro-5-o-anisylphenyl-
{25,26,27,28-tetrapropoxy calix[4]arene}phosphine−borane (S)-11.
Thermal ellipsoids are shown at the 30% probability level. Selected
bond lengths (Å) and angles (deg): C1−P = 1.819(2), C7−P =
1.812(3), C14−P = 1.818(3), P−B = 1.851(4); C7−P−C14 =
107.91(14), C7−P−C1 = 108.81(1), C14−P−C1 = 106.37(14), C7−
P−B = 110.55(19), C14−P−B = 112.23(19), C1−P−B = 110.81(17).
a
b
cd
,
entry
1
ligand
conversn (%)
ee (%)
(S)-5a
100
100
100
100
100
100
24
76
58
0
e
2
(S)-5b
3
4
5
(S)-5b
(S,S)-9b
(S,S)-9a
(S,S)-9a
Finally, the free P-chirogenic diphosphines 9a−c were
obtained in excellent yields after decomplexation of their
borane complexes with DABCO in toluene at 50 °C, followed
by filtration on neutral alumina. The enantiomeric excesses of
the diphosphines 9a−c were determined by 31P NMR in the
presence of the chiral palladium complex (R)-12 (Figure 5).21
75
e
6
79
a
Reaction conditions: 0.005 mmol of [Pd(η3-C3H5)Cl]2, 0.012 mmol
of ligand 9a,b or 0.024 mmol of ligand 5a,b, 0.5 mmol of (E)-( )-1,3-
diphenylprop-2-en-1-yl acetate (13), and 1.45 mmol of benzylamine in
b
6 mL of dry CH2Cl2. Reaction times: 19−48 h. Conversion was
c
determined by 1H NMR of the crude mixture. Determined by HPLC
d
e
with a Chiralcel OD-H column. R absolute configuration. Reaction
performed at 0 °C.
Scheme 4. Pd-Catalyzed Allylation of Dimethyl Malonate in
the Presence of P-Chirogenic Calix[4]arene Phosphines 5a
and 9a−c
Figure 5. Structure of the chiral palladium NMR reagent used to check
the enantiomeric purity of the calix[4]arene diphosphines 9a−c.
All of these diphosphines were obtained with enantioselec-
tivities superior to 98% ee, except in the case of the
diphosphine 9c, bearing a ferrocenyl substituent on the
phosphorus center (87% ee).
The use of P-chirogenic mono- and diphosphines 5a−c (and
9a−c) as chiral ligands was evaluated in the palladium-catalyzed
asymmetric allylic alkylation of dimethyl malonate and
benzylamine by (E)-( )-1,3-diphenylprop-2-en-1-yl acetate
(13). The results are summarized in Tables 1 and 2,
respectively.
In the first case, the alkylation of malonate was performed in
the presence of an (allyl)palladium complex generated in situ
from [Pd(η3-C3H5)Cl]2 (1 mol %) and monophosphine 5a (4
mol %) or diphosphines 9a−c (2 mol %) (Scheme 4). The
nucleophile was generated from dimethyl malonate in the
presence of a base (N,O-bis(trimethylsilyl)acetamide (BSA) or
n-BuLi). With reaction times ranging from 1 to 20 h at room
temperature or 0 °C, full conversions were obtained for all
phosphine ligands. The chemoselectivity toward the malonate
derivative 14 was excellent for all runs, and no isomerized cis
product was observed in the crude reaction mixture. The use of
the P-chirogenic mono- and diphosphines 5a and 9b,c and
BSA/KOAc as base leads to the (S)-alkylated product 14 in
dichloromethane with modest enantioselectivities: i.e., 5−40%
ee (Table 1, entries 1, 3, and 4). Conversely, when the reaction
was performed with the calix[4]arene diphosphine 9a under the
same conditions, higher asymmetric induction was obtained
(70% ee; Table 1, entry 2). When the mixtures BSA/LiOAc
and BSA/NaOAc were used for the base of the catalysis, the
diphosphine 9a afforded similar enantioselectivities (69% ee,
E
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Table 1, entries 5 and 6). In the case where the reaction was
carried out at 0 °C with BSA/KOAc as the base in
dichloromethane, a slight increase of the ee value was observed
(73% ee, Table 1, entry 7). Finally, the best result was obtained
when the catalyzed reaction was performed in the presence of
diphosphine 9a as ligand, with n-BuLi as base in THF at 0 °C,
leading to the (S)-alkylated malonate 14 with 82% ee (Table 1,
entry 8).
In the case of the allylation of the benzylamine, the reaction
was performed in the presence of an (allyl)palladium complex
generated in situ from [Pd(η3-C3H5)Cl]2 (1 mol %) and
monophosphine 5a (4.8 mol %) or diphosphines 9a−c (2.4
mol %) (Scheme 5).
Figure 6. Drawings of the HOMO (a) and LUMO (b) of the
calix[4]arenyl-diphosphine (S,S)-9a/Pd(allyl) complex.
finally in good agreement with a complexed η1-allyl moiety to
the Pd center. Although the η3 bonding mode is expected, a few
Pd complexes containing η1-allyl ligands have been described in
the literature and their stabilization was notably explained by
the presence of a rigid ligand environment in the sphere of
coordination.22 Consequently, the nucleophilic attack occurs
more favorably on the allylic carbon linked to the palladium,
which shows a very large atomic contribution to the LUMO
precisely at this carbon atom. This regioselectivity of the
nucleophilic attack explains the formation of products 14 and
15 with S and R configurations, respectively, whether the
reagent is dimethyl malonate or benzylamine (Scheme 6).
Scheme 5. Pd-Catalyzed Allylation of Benzylamine in the
Presence of P-Chirogenic Mono- and Diphosphines 5a−c
and 9a−c
All calix[4]arene mono- and diphosphine ligands carry out
the allylation with excellent conversions to give products with
the R configuration (Scheme 5; Table 2). As observed using
dimethyl malonate, the chemoselectivity of the reaction was
excellent and no isomerized cis product was formed during the
reaction. Initial experiments were carried out using the P-
chirogenic monophosphines 5a,b with a 2.4/1 ligand/palladium
ratio in dichloromethane. When the catalysis was achieved in
the presence of the P-chirogenic monophosphine (S)-5a, the
reaction required 48 h to be complete and the allylated amine
(R)-15 was obtained with 24% ee (Table 2, entry 1). In the
presence of the monophosphine ligand (S)-5b, the asymmetric
induction reaches 58% ee, but when the reaction temperature
decreased to 0 °C, the enantiomeric excesses grow up to 76%
ee (Table 2, entries 2 and 3). On the other hand, surprisingly,
when the reaction was performed in dichloromethane in the
presence of P-chirogenic diphosphines (S,S)-9b, the allylated
amine 15 was unexpectedly obtained in racemic form (Table 2,
entry 4). In contrast, the use of the calix[4]arene diphosphine
(S,S)-9a under the same conditions afforded the product (R)-
15 with 75% ee (Table 2, entry 5). Finally, when catalysis with
the diphosphine (S,S)-9a was carried out at 0 °C, the
asymmetric induction reached 79% ee (Table 2, entry 6).
In order to provide an explanation for the enantioselectivity
of the catalyzed allylation affording the products (S)-14 and
(R)-15 from dimethyl malonate and benzylamine, respectively,
computer modelings were examined in the case of the
calix[4]arenediphosphine 9a. This is exemplified in Figure 6,
showing the HOMO and LUMO of the calix[4]arenyl-
diphosphine (S,S)-9a/Pd(allyl) complex, for which an opti-
mized geometry was computed.
Scheme 6. Stereochemical Nucleophilic Approach of the Pd-
Catalyzed Allylation in the Presence of P-Chirogenic
Diphosphine 9a
CONCLUSION
■
The first synthesis of P-chirogenic mono- and diphosphine
ligands located on the upper rim of a calix[4]arene moiety was
achieved in three steps starting from the (+)- or (−)-ox-
azaphospholidine−borane complex 1, derived from ephedrine.
These ligands were tested with standard Pd-catalyzed
asymmetric allylic substitutions of racemic (E)-1,3-diphenyl-
prop-2-en-1-yl acetate with dimethyl malonate and benzyl-
amine. The reaction of (E)-1,3-diphenylprop-2-en-1-yl acetate
with dimethyl malonate catalyzed by [Pd(η3-C3H5)Cl]2 and
diphosphine 9 resulted in high enantioselectivity (82% ee)
using n-BuLi as base. In the case of the allylic amination of (E)-
1,3-diphenylprop-2-en-1-yl acetate with benzylamine the N-
benzyl-1,3-diphenyl-2-propenylamine 15 was obtained in high
yields and with asymmetric inductions up to 79% ee using the
mono- or diphosphines derived from calix[4]arenes 5a and 9a.
Computer modeling of the calix[4]arenyl diphosphine (S,S)-
9a/Pd(allyl) complex indicates a clear dissymmetry of both the
HOMO and LUMO, in good agreement with a complexed η1-
allyl moiety. The dissymmetry of the LUMO is particularly
determinant in the regio- and enantioselectivity with respect to
attack by the C- or N-nucleophiles. The complexation of
substrate to this palladium complex explains why the C2
symmetry of the P-chirogenic calixarene diphosphine plays a
Surprisingly, despite the C2 symmetry of the calix[4]arene
diphosphine ligand 9a, the two molecular orbitals show a high-
level dissymmetry of the complexed allyl moiety (Figure 6).
The dissymmetry of the molecular orbitals is induced by the
complexation of the diphenylpropenyl group in a W
conformation and with an inclination with respect to the
median plane crossing via the palladium and the two
phosphorus atoms. As the Pd−C bonds with the allyl moiety
are 2.156, 2.925, and 3.810 Å, respectively, the structure is
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basis sets assigned for different atom types. C, H, O, and P were
described by 3-21G*;34−39 palladium was described by SBKJC ECP
and VDZ.40−43
key role in the enantioselectivity of these Pd-catalyzed
allylations.
Synthesis of the Aminophosphine−Boranes 2 and 7. (Sp)-
(−)-N-Methyl[(1S,2R)(2-hydroxy-1-phenyl)ethyl]amino{25,26,27,28-
tetrapropoxycalix[4]arene}phenylphosphine−Borane (2a). A solu-
tion of sec-butyllithium (1.4 M in hexane, 1.8 mL, 2.5 mmol) was
added under argon at −78 °C to a solution of 5-bromo-25,26,27,28-
tetrapropoxycalix[4]arene (1.5 g, 2.2 mmol) in THF (3 mL). After 45
min, the mixture was added slowly to a solution of (+)-oxazaphos-
pholidine−borane 1 (0.7 g, 2.5 mmol) in THF (3 mL). The reaction
mixture was warmed to room temperature. When the starting complex
1 was totally consumed (TLC), the mixture was hydrolyzed with water
and then extracted with CH2Cl2. The organic layers were dried with
anhydrous MgSO4, and the solvent was removed. The residue was
purified by column chromatography on silica gel using toluene/ethyl
acetate 9/1 as eluent to afford the aminophosphine− borane 2a, which
was recrystallized with methanol (1.62 g, yield 84%): white solid; mp
EXPERIMENTAL SECTION
■
General Procedures. All reactions were carried out under an
argon atmosphere in dried glassware with magnetic stirring. Solvents
were dried prior to use. Tetrahydrofurane (THF) and toluene were
distilled from sodium/benzophenone and stored under argon.
Dichloromethane (CH2Cl2) was distilled from CaH2. Hexane and
propan-2-ol for HPLC were of chromatographic grade and were used
without further purification. sec-Butyllithium (1.4 M in cyclohexane),
tert-butyllithium (1.6 M in pentane), methyllithium (1.6 M in Et2O),
1,4-diazabicyclo[2.2.2]octane (DABCO), ferrocene, 2-bromoanisole,
BH3.SMe2, and (R)-(+)-1-phenylethylamine were purchased from
Aldrich, Acros, or Alfa Aesar and used as received. (+)- and
(−)-ephedrine were purchased from Aldrich and dried by an
azeotropic shift of toluene on a rotary evaporator. [PdCl(η3-C3H5)]2
was purchased from Strem. 5-Bromo-25, 26, 27, 28-
tetrapropoxycalix[4]arene and 5,17-dibromo-25,26,27,28-
tetrapropoxycalix[4]arene10a were prepared according to literature
procedures. (2R,4S,5R)-(+)-3,4-dimethyl-2,5-diphenyl-1,3,2-oxaza-
phospholidine-2-borane (1) and its enantiomer (2S,4R,5S)-(−)-1
were prepared from the appropriate (−)- or (+)-ephedrine, as
previously described.18 (Sp)-(+)-N-methyl-N-[(1S,2R)(1-hydroxy-2-
methyl-1-phenyl-2-propyl)]aminomethylphenyl phosphine−borane
2′a, (Rp)-(+)-N-methyl-N-[(1S,2R)(1-hydroxy-2-methyl-1-phenyl-2-
propyl)]amino-o-anisylphenylphosphine−borane (2′b) and (Rp)-
(+)-N-methyl-N-[(1S,2R)(1-hydroxy-2-methyl-1-phenyl-2-propyl)]-
aminoferrocenylphosphine−borane (2′c) were prepared from
(+)-ephedrine according to the published procedure.18 (R)-(+)-di-μ-
chlorobis[2[1-(dimethylamino)ethyl]phenyl-C,N]dipalladium (12)
was prepared from (R)-(+)-1-phenylethylamine according to literature
procedures.21 The toluene/HCl solution was obtained by bubbling
HCl gas, and the resulting solution was titrated before use. Reactions
were monitored by thin-layer chromatography (TLC) using 0.25 mm
E. Merck precoated silica gel plates. Visualization was accomplished
with UV light and/or appropriate staining reagents. Flash chromatog-
raphy was performed with the indicated solvents using silica gel 60
(particle size 35−70 μm; Acros) or aluminum oxide 90 standardized
(Merck). NMR spectra (1H, 13C and 31P) were recorded on Bruker
500 MHz Avance DRX, 300 MHz Avance, and 600 MHz Avance II
spectrometers at ambient temperature. Data are reported as follows: s
= singlet, d = doublet, t = triplet, q = quartet, m = multiplet, br s =
broad singlet; integration, coupling constant(s) in Hz. Melting points
were measured on a Kofler bench melting point apparatus and are
uncorrected. Optical rotation values were determined at 25 °C on a
Perkin-Elmer 341 polarimeter, using a 10 cm quartz vessel. Mass
spectral analyses were performed on the Bruker Daltonics microTOF-
Q apparatus at Burgundy University.
25
106−109 °C. Rf = 0.20 (AcOEt/toluene 1/9). [α]D = −8.0 (c 1.0,
CHCl3). 1H NMR (CDCl3, 300 MHz): δ 7.30−6.93 (m, 10H,
CHarom), 6.75−6.50 (m, 8H, CHarom), 6.17 (m, 3H, CHarom), 4.56 (d,
1H, J = 5.1 Hz, CHO), 4.34 (AX system, 4H, J = 13.1, 12.9 Hz,
ArCH2Ar), 3.95 (m, 5H, CHCH3 and CH2O), 3.64 (m, 4H, CH2O,
OPr), 3.11 (AX system, 4H, J = 13.5, 12.6 Hz, ArCH2Ar), 1.97 (m,
4H, CH2CH3, OPr), 1.83 (m, 4H, CH2CH3, OPr), 1.52 (d, 3H, J = 7.2
Hz, CH3N), 1.10 (d, 3H, J = 6.9 Hz, CH3CH), 1.02 (m, 6H, CH3,
OPr), 0.86 (m, 6H, CH3, OPr). 13C NMR (CDCl3, 75 MHz): δ 157.7
(d, J = 3.0 Hz, Carom), 157.1 (d, J = 18.0 Hz, Carom), 155.6 (s, Carom),
142.6 (s, Carom), 137.9 (s, Carom), 136.5 (d, J = 5.3 Hz, Carom), 136.3 (d,
J = 12.8 Hz, Carom), 134.4 (d, J = 12.8 Hz, Carom), 134.2 (d, J = 12.8 Hz,
Carom), 133.8 (d, J = 15.8 Hz, Carom), 132.4 (d, J = 12.8 Hz, CHarom),
132.3 (d, J = 10.5 Hz, CHarom), 131.7 (d, J = 9.8 Hz, CHarom), 130.5 (d,
J = 32.4 Hz, CHarom), 130.1 (d, J = 32.4 Hz, CHarom), 129.1 (s,
CHarom), 128.8 (d, J = 7.5 Hz, CHarom), 128.7 (s, CHarom), 128.3 (d, J =
4.5 Hz, CHarom), 128.0 (d, J = 10.6 Hz, CHarom), 127.6 (d, J = 9.8 Hz,
CHarom), 126.3 (s, CHarom), 125.3 (s, CHarom), 122.7 (s, CHarom), 122.3
(d, J = 5.3 Hz, CHarom), 78.6 (d, J = 3.8 Hz, CHO), 77.5 (s, CH2O,
OPr), 77.4 (s, CH2O, OPr), 76.7 (s, CH2O, OPr), 76.6 (s, CH2O,
OPr), 58.0 (d, J = 10.6 Hz, CHCH3), 30.9 (s, ArCH2Ar), 30.8 (s,
ArCH2Ar), 28.0 (d, J = 3.8 Hz, CH3N), 23.5 (s, CH2CH3, OPr), 23.1
(s, CH2CH3, OPr), 23.0 (s, CH2CH3, OPr), 13.0 (d, J = 3.8 Hz,
CH3CH), 10.7 (s, CH3, OPr), 10.6 (s, CH3, OPr), 10.2 (s, CH3, OPr),
10.0 (s, CH3, OPr). 31P NMR (CDCl3, 121 MHz): δ +69.5. HRMS
(ESI-Q-TOF): calcd for C56H69BNO5PNa [M + Na]+ 900.49078,
found 900.49334. Anal. Calcd for C56H69BNO5P (877.95): C, 76.61;
H, 7.92; N, 1.60. Found: C, 76.91; H, 7.62; N, 1.69.
(Sp,Sp)-5,17-Bis[(−)-N-methyl[(1S,2R)(2-hydroxy-1-phenyl)ethyl]-
a m i n o ] { 2 5 , 2 6 , 2 7 , 2 8 - t e t r a p r o p o x y c a l i x [ 4 ] a r e n e } -
diphenylphosphine−Diborane (7). This compound was prepared
according to a procedure similar to that for 2a, using 5,17-dibromo-
25,26,27,28-tetrapropoxycalix[4]arene (3.3 g, 4.1 mmol) and sec-
butyllithium (1.4 M in hexane, 9.7 mL, 13.5 mmol) to generate the
corresponding (25,26,27,28-tetrapropoxycalix[4]arene-5,17-yl)-
dilithium reagent and (+)-oxazaphospholidine−borane 1 (2.4 g, 8.3
mmol): yield 3.48 g, 73%; white solid; mp 236−238 °C. Rf = 0.26
Crystal Structure Determination. Diffraction data were collected
on a Nonius Kappa CCD or Nonius Kappa APEX II diffractometer
equipped with a nitrogen jet stream low-temperature system (Oxford
Cryosystems). The X-ray source was graphite-monochromated Mo Kα
radiation (λ = 0.71073 Å) from a sealed tube. The lattice parameters
were obtained by a least-squares fit to the optimized setting angles of
the entire set of collected reflections. No significant temperature drift
was observed during the data collections. Data were reduced by using
DENZO23 software without applying absorption corrections; the
missing absorption corrections were partially compensated by the data
scaling procedure in the data reduction. The structures were solved by
direct methods using the SIR9224 program. Refinements were carried
out by full-matrix least squares on F2 using the SHELXL9725 program
on the complete set of reflections. Absolute configurations of all
compounds were determined reliably from anomalous scattering, using
the Flack method.20
25
(AcOEt/toluene 1/9). [α]D = −33.0 (c 1, CHCl3). 1H NMR
(CDCl3, 300 MHz): δ 7.41−7.09 (m, 26H, CHarom), 6.12 (t, 2H, J =
7.5 Hz, CHarom), 5.90 (d, 4H, J = 7.8 Hz, CHarom), 4.80 (d, 2H, J = 3.9
Hz, CHO), 4.34 (AX system, 6H, J = 13.5 Hz, ArCH2Ar and CHCH3),
4.00 (t, 4H, J = 8.1 Hz, CH2O, OPr), 3.54 (t, 4H, J = 6.6 Hz, CH2O,
OPr), 3.05 (AX system, 4H, J = 14.4 Hz, ArCH2Ar), 2.46 (d, 6H, J =
7.8 Hz, CH3N), 1.87 (m, 4H, CH2CH3, OPr), 1.76 (m, 4H, CH2CH3,
OPr), 1.24 (d, 6H, J = 6.6 Hz, CH3CH), 1.00 (t, 6H, J = 7.3 Hz, CH3,
OPr), 0.84 (t, 6H, J = 7.5 Hz, CH3, OPr). 13C NMR (CDCl3, 75
MHz): δ 160.8 (d, J = 2.2 Hz, Carom), 155.2 (s, Carom), 142.7 (s, Carom),
137.4 (d, J = 11.4 Hz, Carom), 137.2 (d, J = 10.6 Hz, Carom), 133.6 (d, J
= 12.4 Hz, CHarom), 133.4 (d, J = 11.0 Hz, CHarom), 132.7 (d, J = 3.5
Hz, Carom), 132.6 (d, J = 10.2 Hz, CHarom), 131.8 (s, Carom), 130.8 (s,
Carom), 130.6 (d, J = 2.3 Hz, CHarom), 128.7 (s, CHarom), 128.3 (d, J =
10.4 Hz, CHarom), 128.0 (s, CHarom), 127.4 (d, J = 5.0 Hz, CHarom),
Computations. The optimization was calculated with Gaussian
09,26 at the Universite
́
de Sherbrooke’s Mammouth supercomputer,
eau Quebecois de Calcul de Haute Performance.
DFT27−30 was calculated by the B3LYP31−33 method with specific
supported by the Res
́
́
́
G
dx.doi.org/10.1021/om400229p | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
126.9 (s, CHarom), 123.5 (s, Carom), 122.6 (s, Carom), 122.3 (s, CHarom),
78.9 (d, J = 8.2 Hz, CHO), 77.2 (s, CH2O, OPr), 76.7 (s, CH2O, OPr),
64.5 (s, CHCH3), 31.5 (br.s, ArCH2Ar), 30.5 (d, J = 3.8 Hz, CH3N),
23.5 (s, CH2CH3, OPr), 23.2 (s, CH2CH3, OPr), 13.6 (s, CH3CH),
10.9 (s, CH3, OPr), 9.8 (s, CH3, OPr). 31P NMR (CDCl3, 121 MHz):
δ +69.8. HRMS (ESI-Q-TOF): calcd for C72H90B2O6P2N2Na [M +
Na]+ 1185.6352, found 1185.6376. Anal. Calcd for C72H90B2O6P2N2 +
CH3OH (1195.12): C, 73.36; H, 7.93; N, 2.34. Found: C, 73.59; H,
8.18; N, 2.43.
silica gel using a petroleum ether/ethyl acetate 8/2 mixture as eluent
(0.56 g, yield 62%): white crystals; mp 213−215 °C. [α]D25 = +33.0 (c
1
1, CHCl3) for 98% ee. Rf = 0.60 (petroleum ether/AcOEt 8/2). H
NMR (CDCl3, 300 MHz): δ 7.59 (m, 5H, CHarom), 7.26 (m, 2H,
CHarom), 7.04 (m, 2H, CHarom), 6.93 (t, 1H, J = 5.2 Hz, CHarom), 6,78
(m, 3H, CHarom), 6.59 (t, 1H, J = 5.3 Hz, CHarom), 6.38 (m, 4H,
CHarom), 6.28 (m, 2H, CHarom), 4.37 (AX system, 4H, J = 13.3, 5.8 Hz,
ArCH2Ar), 3.83 (dd, 4H, J = 15.6, 5.8 Hz, CH2O, OPr), 3.71 (m, 4H,
CH2O, OPr), 3.39 (s, 1H, CH3O), 3.06 (AX system, 4H, J = 17.0, 13.3
Hz, ArCH2Ar), 1.87 (m, 8H, J = 7.3 Hz, CH2CH3, OPr), 0.95 (t, 6H, J
= 7.5 Hz, CH3, OPr), 0.88 (t, 6H, J = 7.5 Hz, CH3, OPr). 13C NMR
(CDCl3, 75 MHz): δ 161.3 (d, J = 2.2 Hz, Carom), 156.8 (d, J = 14.8
Hz, Carom), 155.9 (s, Carom), 135.9 (s, Carom), 135.6 (d, J = 9.7 Hz,
Carom), 134.6 (d, J = 12.1 Hz, CHarom), 134.5 (d, J = 11.0 Hz, CHarom),
133.9 (s, CHarom), 133.7 (d, J = 10.2 Hz, CHarom), 133.5 (s, CHarom),
133.4 (s, CHarom), 132.6 (d, J = 2.2 Hz, CHarom), 130.1 (s, CHarom),
128.4 (s, CHarom), 128.1 (d, J = 10.4 Hz, CHarom), 127.8 (d, J = 4.4 Hz,
CHarom), 122.1 (s, CHarom), 120.9 (s, Carom), 120.8 (s, CHarom), 120.5
(s, CHarom), 77.2 (s, CH2O, OPr), 76.8 (s, CH2O, OPr), 76.8 (s,
CH2O, OPr), 76.7 (s, CH2O, OPr), 55.1 (s, CH3O), 30.9 (s,
ArCH2Ar), 30.9 (s, ArCH2Ar), 30.8 (s, ArCH2Ar), 30.8 (s, ArCH2Ar),
23.3 (s, CH2CH3, OPr), 23.3 (s, CH2CH3, OPr), 23.2 (s, CH2CH3,
OPr), 23.1 (s, CH2CH3, OPr), 10.4 (s, CH3, OPr), 10.1 (s, CH3, OPr);
31P NMR (CDCl3, 121 MHz): δ +17.1. HRMS (ESI-Q-TOF): calcd
Preparation of Monophosphine− and Diphosphine−Bor-
anes 4a−c and 8a−c (Route a). (S)-(−)-Methylphenyl{25,26,27,28-
tetrapropoxycalix[4]arene}phosphine−borane (4a). In a 50 mL two-
necked flask equipped with a magnetic stirrer, an argon inlet, and a
rubber septum was introduced the aminophosphine− borane 2a (0.53
g, 0.6 mmol). A solution of HCl in toluene (0.4 M, 15 mL, 6 mmol)
was added with stirring at room temperature, without previous
dissolution of 2a. After 2 h, the acidolysis completion was controlled
by TLC, and the precipitate of ephedrine hydrochloride was filtered off
with a Millipore 4 μm filter. The excess HCl was removed by several
vacuum/argon cycles. The 5-(chlorophenylphosphino borane)-
25,26,27,28-tetrapropoxycalix[4]arene obtained was used without
further purification (31P NMR (CDCl3, 121 MHz): δ +93.6).
Methyllithium (1.6 M in Et2O, 1.12 mL, 1.8 mmol) was added
dropwise at −78 °C to the vigorously stirred toluene solution of the
chlorophosphine−borane 3a. The reaction mixture was warmed to
room temperature. After 2 h, the mixture was hydrolyzed with water
and then extracted with CH2Cl2. The organic layers were dried with
anhydrous MgSO4, and the solvent was removed. The residue was
purified by column chromatography on silica gel using hexane/ethyl
acetate 95/5 as eluent to afford compound 4a, which was recrystallized
with methanol (0.38 g, yield 84%): white solid; mp 124−126 °C. Rf =
for C53H62BNaO5P [M + Na]+ 843.43201, found 843.42947. Anal.
Calcd for C53H62BO5P (820.85): C, 77.55; H, 7.61. Found: C, 77.30;
H, 7.53.
The enantiomeric excess of 4b was determined by HPLC analysis
on a Lux 5 μ cellulose-2 column, hexane/i-PrOH 99/1; 1 mL/min, 40
°C, λ 254 nm, tR(R) = 15.6 min, tR(S) = 19.3 min.
25
(S)-(−)-Ferrocenylphenyl{25,26,27,28-tetrapropoxycalix[4]arene}-
phosphine−Borane (4c). In a 50 mL two-necked flask equipped with
a magnetic stirrer and an argon inlet was added 1.37 mL of tert-
butyllithium (1.6 M in pentane, 2.2 mmol) with stirring at 0 °C to a
solution of ferrocene (0.465 g, 2.5 mmol) in 8 mL of THF. After 1 h,
the ferrocenyllithium reagent was added at −78 °C to a toluene
solution of the chlorophosphine−borane 3a (1.05 mmol), previously
prepared as described above. The resulting mixture was progressively
warmed to room temperature and stirred for 2 h. After hydrolysis with
water, the aqueous phase was extracted several times with CH2Cl2.
The combined organic layers were dried over MgSO4, and the solvents
were removed. The residue was purified by chromatography on silica
gel using diethyl ether/petroleum ether 5/95 as eluent, to afford
compound 4c in 46% yield (0.43 g): orange solid; mp 97−99 °C. Rf =
0.32 (AcOEt/hexane 5/95). [α]D = −30.0 (c 0.8, CHCl3) for 99%
ee. 1H NMR (CDCl3, 300 MHz): δ 7.41−7.29 (m, 5H, CHarom),
6.84−6.39 (m, 11H, CHarom), 4.38 (AX system, 4H, J = 13.2 Hz,
ArCH2Ar), 3.84 (m, 4H, CH2O, OPr), 3.74 (m, 4H, CH2O, OPr),
3.11 (AX system, 4H, J = 13.2 Hz, ArCH2Ar), 1.86 (m, 8H, CH2CH3,
OPr), 1.38 (d, 3H, J = 2.6 Hz, CH3P), 0.94 (m, 12H, CH3, OPr). 13
C
NMR (CDCl3, 75 MHz): δ 158.8 (d, J = 11.3 Hz, Carom), 159.6 (s,
Carom), 156.1 (d, J = 13.8 Hz, Carom), 135.6 (d, J = 6.6 Hz, Carom), 135.1
(d, J = 12.7 Hz, Carom), 134.9 (s, Carom), 134.6 (d, J = 8.9 Hz, Carom),
132.0 (d, J = 9.4 Hz, CHarom), 131.8 (s, CHarom), 131.6 (d, J = 3.3 Hz,
CHarom), 131.5 (s, CHarom), 130.6 (d, J = 2.3 Hz, CHarom), 128.6 (d, J =
4.0 Hz, CHarom), 128.5 (s, CHarom), 128.2 (d, J = 13.0 Hz, CHarom),
128.0 (d, J = 24.0 Hz, CHarom), 122.3 (d, J = 1.1 Hz, CHarom), 122.1 (s,
CHarom), 77.1 (s, CH2O, OPr), 77.0 (s, CH2O, OPr), 76.7 (s, CH2O,
OPr), 76.6 (s, CH2O, OPr), 31.0 (s, ArCH2Ar), 30.9 (s, ArCH2Ar),
30.8 (s, ArCH2Ar), 30.7 (s, ArCH2Ar), 23.4 (s, CH2CH3, OPr), 23.3
(s, CH2CH3, OPr), 23.1 (s, CH2CH3, OPr), 13.0 (d, J = 44.9 Hz,
CH3P), 10.5 (s, CH3, OPr), 10.4 (s, CH3, OPr), 10.2 (s, CH3, OPr).
31P NMR (CDCl3, 121 MHz): δ +9.0. HRMS (ESI-Q-TOF): calcd for
25
0.32 (Et2O/petroleum ether 5/95). [α]D = −2.7 (c 0.4, CHCl3) for
93% ee. 1H NMR (CDCl3, 300 MHz): δ 7.40−7.25 (m, 5H, CHarom),
6.90 (m, 2H, CHarom), 6.76 (m, 2H, CHarom), 6.63 (m, 1H, CHarom),
6.49−6.28 (m, 6H, CHarom), 4.36 (AX system, 6H, ArCH2Ar and Fc),
4.27 (m, 1H, Fc), 4.18 (m, 1H, Fc), 4.00 (s, 5H, Fc), 3.78 (m, 8H,
CH2O, OPr), 3.10 (AX system, 4H, ArCH2Ar), 1.85 (m, 8H,
CH2CH3, OPr), 0.90 (m, 12H, CH3, OPr). 13C NMR (CDCl3, 75
MHz): δ 159.3 (d, J = 2.5 Hz, Carom), 156.8 (s, Carom), 156.0 (d, J = 2.6
Hz, Carom), 135.7 (d, J = 11.2 Hz, Carom), 135.5 (d, J = 3.5 Hz, Carom),
134.7 (d, J = 4.5 Hz, Carom), 133.9 (s, Carom), 133.1 (d, J = 4.8 Hz,
CHarom), 133.0 (d, J = 5.8 Hz, CHarom), 132.5 (d, J = 9.6 Hz, CHarom),
131.7 (s, Carom), 130.4 (d, J = 2.8 Hz, CHarom), 128.4 (d, J = 5.3 Hz,
CHarom), 128.2 (d, J = 4.5 Hz, CHarom), 128.1 (d, J = 1.7 Hz, CHarom),
127.8 (d, J = 2.6 Hz, CHarom), 122.3 (br.s, CHarom), 122.1 (s, CHarom),
76.9 (s, CH2O, OPr), 76.8 (s, CH2O, OPr), 76.7 (s, CH2O, OPr), 72.4
(d, J = 10.3 Hz, Fc), 72.5 (d, J = 9.3 Hz, Fc), 71.6 (d, J = 7.5 Hz, Fc),
71.3 (d, J = 7.6 Hz, Fc), 70.2 (d, J = 70.9 Hz, Fc), 69.6 (br.s, Fc), 30.9
(s, ArCH2Ar), 30.8 (s, ArCH2Ar), 23.3 (s, CH2CH3, OPr), 23.2 (s,
CH2CH3, OPr), 10.4 (s, CH3, OPr), 10.2 (s, CH3, OPr). 31P NMR
(CDCl3, 121 MHz): δ +15.0. HRMS (ESI-Q-TOF) calcd for
C56H64BFeO4P [M]+ 898.3990, found 898.3993. Anal. Calcd for
C56H64BFeO4P (898.75): C, 74.84; H, 7.18. Found: C, 74.53; H, 7.14.
The enantiomeric excess of 4c was determined by HPLC analysis
on a Lux 5 μ cellulose-2 column, hexane/i-PrOH 98/2, 1 mL/min, 40
°C, λ 254 nm, tR(S) = 8.7 min, tR(R) = 10.9 min.
C47H58BO4PNa [M + Na]+ 751.4066, found 751.4068. Anal. Calcd for
C47H58BO4P (728.75): C, 77.46; H, 8.02. Found: C, 77.33; H, 8.09.
The enantiomeric excess of 4a was determined by HPLC analysis
on a Lux 5 μ cellulose-2 column, hexane/i-PrOH 99/1, 1 mL/min, 40
°C, λ 254 nm, tR(R) = 27.7 min, tR(S) = 34.6 min.
(S)-(+)-(o-Anisylphenyl{25,26,27,28-tetrapropoxycalix[4]arene}-
phosphine−Borane (4b). In a two-necked flask equipped with a
magnetic stirrer and an argon inlet, 1.8 mL (1.4 M in hexane, 2.8
mmol) of sec-butyllithium was added. The mixture was cooled to 0 °C,
and 0.3 mL (2.8 mmol) of 2-bromoanisole was slowly added with a
syringe while stirring. After the formation of a white precipitate, the
mixture was stirred for 1 h at 0 °C. The organolithium reagent was
dissolved with a minimum amount of dry THF before use. After 1 h,
the o-anisyllithium was added at −78 °C to a toluene solution of the
chlorophosphine−borane 3a (1 mmol), previously prepared as
described above. The resulting mixture was progressively warmed to
room temperature and stirred for 2 h. After hydrolysis, the aqueous
layer was extracted two times with dichloromethane. The organic
layers were dried over anhydrous MgSO4, and the solvent was
removed. The residue was purified by column chromatography on
H
dx.doi.org/10.1021/om400229p | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
(S,S)-(−)-5,17-Bis[(methylphenylphosphinoborane)]{25,26,27,28-
tetrapropoxycalix[4]arene} (8a). In a 50 mL two-necked flask
equipped with a magnetic stirrer, an argon inlet, and a rubber septum
was introduced the bis(aminophosphine)−borane 7 (2.5 g, 2.15
mmol). A solution of HCl in toluene (0.32 M, 81 mL, 25.8 mmol) was
added with stirring at room temperature, without previous dissolution
of 7. After 2 h, the acidolysis completion was controlled by TLC, and
the precipitate of ephedrine hydrochloride was filtered off with a
Millipore 4 μm filter. The excess HCl was removed by several
vacuum/argon cycles. The 5,17-(bischlorophenylphosphinoborane)-
25,26,27,28-tetrapropoxycalix[4]arene obtained was used without
further purification (31P NMR (CDCl3, 121 MHz): δ +92.5).
Methyllithium (1.6 M in Et2O, 17.9 mL, 10.7 mmol) was added
dropwise at −78 °C to the vigorously stirred toluene solution of the
bis(chlorophosphine)−borane intermediate. The reaction mixture was
warmed to room temperature. After 2 h, the mixture was hydrolyzed
with water and then extracted with CH2Cl2. The organic layers were
dried with anhydrous MgSO4, and the solvent was removed. The
residue was purified by column chromatography on silica gel using
dichloromethane/petroleum ether 2/8 as eluent (0.85 g, yield 46%):
white solid; mp 192−194 °C. Rf = 0.54 (CH2Cl2/petroleum ether 2/
8). [α]D = −0.8 (c 0.4, CHCl3) for 98% ee. H NMR (CDCl3, 300
MHz): δ 7.65−7.52 (m, 4H, CHarom), 7.37−7.19 (m, 10H, CHarom),
6.17 (t, 2H, J = 7.6 Hz, CHarom), 5.9 (d, 4H, J = 7.8 Hz, CHarom), 5.93
(m, 4H, CHarom), 4.35 (AX system, 4H, J = 13.4 Hz, ArCH2Ar), 4.00
(m, 4H, CH2O, OPr), 3.57 (t, 4H, J = 6.7 Hz, CH2O, OPr), 3.09 (AX
system, 4H, J = 13.4 Hz, ArCH2Ar), 1.82 (m, 14H, CH2CH3 and
CH3P), 1.00 (t, 6H, J = 7.5 Hz, CH3, OPr), 0.83 (t, 6H, J = 7.5 Hz,
CH3, OPr). 13C NMR (CDCl3, 75 MHz): δ 155.1 (s, Carom), 137.7 (d,
J = 11.3 Hz, Carom), 132.5 (br.s, CHarom), 131.5 (d, J = 9.2 Hz, CHarom),
130.8 (s, CHarom), 128.7 (d, J = 9.9 Hz, CHarom), 127.5 (s, CHarom),
122.3 (s, CHarom), 121.6 (s, Carom), 77.1 (s, CH2O, OPr), 76.7 (s,
CH2O, OPr), 30.9 (s, ArCH2Ar), 23.5 (s, CH2CH3, OPr), 23.1 (s,
CH2CH3, OPr), 12.4 (d, J = 60.7 Hz, CH3P), 10.8 (s, CH3, OPr), 9.8
(s, CH3, OPr). 31P NMR (CDCl3, 121 MHz): δ +8.5. HRMS (ESI-Q-
TOF): calcd for C54H68B2O4P2Na [M + Na]+ 887.46712, found
887.46590. Anal. Calcd for C54H68B2O4P2 + CH3OH (896.74): C,
73.67; H, 8.09. Found: C, 74.04; H, 8.37.
Calcd for C66H76B2O6P2 (1048.89): C, 75.58; H, 7.30. Found: C,
75.35; H, 7.26.
(S,S)-(−)-5,17-Bis[(ferrocenylphenylphosphinoborane)]-
{25,26,27,28-tetrapropoxycalix[4]arene} (8c). This compound was
prepared from bis(aminophosphine)−borane 7 (1.7 g, 1.45 mmol)
according to a procedure similar to that for 8a, using ferrocenyllithium
in place of the methyllithium. The ferrocenyllithium was previously
prepared by deprotonation of ferrocene (1.35 g, 7.3 mmol) with tert-
butyllithium (1.6 M in pentane, 4.6 mL, 7.3 mmol). After workup, the
residue was purified by column chromatography on silica gel using a
petroleum ether/ethyl acetate 9/1 mixture as eluent (0.80 g, yield
46%): orange solid; mp 154−156 °C. Rf = 0.33 (AcOEt/petroleum
25
ether 1/9). [α]D = −8.4 (c 0.4, CHCl3) for 84% ee. 1H NMR
(CDCl3, 300 MHz): δ 7.49 (m, 4H, CHarom), 7.40−7.25 (m, 10H,
CHarom), 6.14 (t, 2H, J = 7.6 Hz, CHarom), 5.95 (m, 4H, CHarom), 4.46
(AX system, 8H, ArCH2Ar and Fc), 4.38 (m, 2H, Fc), 4.34 (m, 2H,
Fc), 4.09 (s, 10H, Fc), 4.01 (t, 4H, J = 8.2 Hz, CH2O, OPr), 3.85 (t,
4H, J = 6.7 Hz, CH2O, OPr), 3.08 (AX system, 4H, ArCH2Ar), 1.86
(m, 4H, CH2CH3, OPr), 1.76 (m, 4H, CH2CH3, OPr), 0.99 (t, 6H, J =
7.3 Hz, CH3, OPr), 0.82 (t, 6H, J = 7.5 Hz, CH3, OPr). 13C NMR
(CDCl3, 75 MHz): δ 160.7 (d, J = 1.9 Hz, Carom), 155.1 (s, Carom),
137.5 (d, J = 4.8 Hz, Carom), 137.3 (d, J = 4.9 Hz, Carom), 133.7 (d, J =
9.9 Hz, CHarom), 133.2 (s, Carom), 132.4 (d, J = 12.6 Hz, CHarom), 132.2
(s, Carom), 130.5 (s, CHarom), 128.3 (d, J = 10.0 Hz, CHarom), 127.5 (d, J
= 8.6 Hz, CHarom), 123.3 (s, Carom), 122.4 (s, Carom), 122.1 (s, CHarom),
77.1 (s, CH2O, OPr), 76.6 (s, CH2O, OPr), 73.4 (d, J = 11.6 Hz, Fc),
72.1 (d, J = 7.9 Hz, Fc), 71.8 (d, J = 7.2 Hz, Fc), 71.7 (d, J = 7.6 Hz,
Fc), 69.8 (s, Fc), 69.6 (d, J = 68.5 Hz, Fc), 30.9 (br.s, ArCH2Ar), 23.5
(s, CH2CH3, OPr), 23.1 (s, CH2CH3, OPr), 10.8 (s, CH3, OPr), 9.8 (s,
CH3, OPr). 31P NMR (CDCl3, 121 MHz): δ +14.5. HRMS (ESI-Q-
TOF): calcd for C72H80B2Fe2O4P2 [M]+ 1204.44113, found
1204.43551. Anal. Calcd for C72H80B2Fe2O4P2 + CH3OH (1236.72):
C, 70.90; H, 6.85. Found: C, 70.71; H, 7.13.
25
1
Preparation of Monophosphine− and Diphosphine−Bor-
anes (R)-4b and (S,S)-8b (Route b). (R)-(−)-(o-Anisylphenyl-
{25,26,27,28-tetrapropoxycalix[4]arene}phosphine−Borane (4b). In
a 50 mL two-necked flask equipped with a magnetic stirrer, an argon
inlet, and a rubber septum was dissolved 0.67 g (1 mmol) of 5-bromo-
25,26,27,28-tetra-n-propoxycalix[4]arene in 3 mL of THF. After the
solution was cooled to −78 °C 0.81 mL (1.31 M in cyclohexane, 1.1
mmol) of sec-butyllithium was added drop by drop with stirring. After
5 min, a toluene solution containing 1.1 mmol of (S)-o-
anisylchlorophenylphosphine−borane 3′b (prepared according to the
literature procedure18), was slowly added at −78 °C and the reaction
mixture was stirred for 1 h. After hydrolysis, the aqueous layer was
extracted two times with dichloromethane. The organic layers were
dried over anhydrous MgSO4, and the solvent was removed. The
residue was purified by column chromatography on silica gel using a
petroleum ether/ethyl acetate 8/2 mixture as eluent. Yield: 60%. The
analysis of (R)-4b was similar to that already described above for its
enantiomer (S)-4b.
(S,S)-(−)-5,17-Bis[(o-anisylphenylphosphinoborane)]-
{25,26,27,28-tetrapropoxycalix[4]arene} (8b). In a 50 mL two-
necked flask equipped with a magnetic stirrer, an argon inlet, and a
rubber septum was dissolved 0.8 g (1 mmol) of 5,17-dibromo-
25,26,27,28-tetra-n-propoxycalix[4]arene in 5 mL of THF. After the
solution was cooled to −78 °C 1.62 mL (1.31 M in cyclohexane, 2.2
mmol) of sec-butyllithium was added drop by drop with stirring. After
5 min, a toluene solution containing 2.2 mmol of (S)-o-
anisylchlorophenylphosphine−borane 3′b (prepared according to the
literature procedure18) was slowly added at −78 °C, and the reaction
mixture was stirred for 1 h. After hydrolysis, the aqueous layer was
extracted two times with dichloromethane. The organic layers were
dried over anhydrous MgSO4, and the solvent was removed. The
residue was purified by column chromatography on silica gel using a
petroleum ether/ethyl acetate 8/2 mixture as eluent, to afford the
calix[4]arene diphosphine (S,S)-8b in 40% yield (0.42 g), the
monophosphine−borane (R)-4b (0.21 g, 25%), and the 17-chloro
derivative 11 (0.21 g, 25%). The analyses of (R)-4b and (S,S)-8b were
similar to those already described above.
(S,S)-(−)-5,17-Bis[(o-anisylphenylphosphinoborane)]-
{25,26,27,28-tetrapropoxycalix[4]arene} (8b). This compound was
prepared from bis(aminophosphine)−borane 7 (1.7 g, 1.45 mmol)
according to a procedure similar to that for 8a, using o-anisyllithium in
place of methyllithium. The o-anisyllithium was previously prepared by
metal−halide exchange of 2-bromoanisole (1.20 g, 6 mmol) with sec-
butyllithium (1.4 M in cyclohexane, 4.3 mL, 6 mmol). After workup,
the residue was purified by column chromatography on silica gel using
a petroleum ether/ethyl acetate 8/2 mixture as eluent (1.09 g, yield
25
68%): white crystals; mp 169−171 °C. [α]D = −24.5 (c 1, CHCl3)
for 95% ee. Rf = 0.30 (petroleum ether/AcOEt 8/2). 1H NMR
(CDCl3, 300 MHz): δ 7.62 (m, 4H, CHarom), 7.40 (m, 12H, CHarom),
7.26 (dd, 2H, J = 8.8, 2.2 Hz, CHarom), 6.98 (t, 2H, J = 7.2 Hz,
CHarom), 6.88 (m, 2H, CHarom), 6.17 (t, 2H, J = 7.5 Hz, CHarom), 5.98
(t, 4H, J = 7.4 Hz, CHarom), 4.35 (AX system, 4H, J = 13.3 Hz,
ArCH2Ar), 3.99 (m, 4H, CH2O, OPr), 3.55 (m, 10H, CH2O and
CH3O), 3.04 (AX system, 4H, J = 13.3, 7.4 Hz, ArCH2Ar), 1.78 (m,
4H, J = 13.3, 7.4 Hz, CH2CH3, OPr), 0.99 (t, 6H, J = 7.4 Hz, CH3,
OPr) 0.82 (t, 6H, J = 7.4 Hz, CH3, OPr). 13C NMR (CDCl3, 75
MHz): δ 161.4 (d, J = 13.2 Hz, Carom), 160.4 (d, J = 4.2 Hz, Carom),
155.1 (s, Carom), 137.4 (s, Carom), 137.2 (d, J = 9.7 Hz, CHarom), 133.6
(d, J = 11.1 Hz, CHarom), 132.9 (s, CHarom), 132.8 (d, J = 6.4 Hz,
CHarom), 132.7 (s, CHarom), 132.7 (d, J = 10.6 Hz, CHarom), 130.5 (d, J
= 13.2 Hz, CHarom), 128.3 (d, J = 4.7 Hz, CHarom), 128.2 (s, CHarom),
127.4 (s, CHarom), 121.9 (s, CHarom), 121.1 (s, CHarom), 120.7 (s,
CHarom), 118.1 (s, Carom), 111.6 (d, J = 2.2 Hz, CHarom), 111.5 (s,
CHarom), 77.2 (s, CH2O, OPr), 76.8 (s, CH2O, OPr), 76.4 (s, CH2,
OPr), 55.3 (s, CH3O), 30.9 (s, ArCH2Ar), 23.5 (s, CH2CH3, OPr),
23.1 (s, CH2CH3, OPr), 10.8 (s, CH3, OPr), 9.8 (s, CH3, OPr). 31P
NMR (CDCl3, 121 MHz): δ +17.3. HRMS (ESI-Q-TOF): calcd for
C66H76B2NaO6P2 [M + Na]+ 1071.51955, found 1071.51431. Anal.
I
dx.doi.org/10.1021/om400229p | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
( S)- (−) -17 -C hloro -5 -o-ani syl pheny l{25 , 2 6, 27, 2 8-
tetrapropoxycalix[4]arene}phosphine−Borane (11). This was a
byproduct obtained during the preparation of diphosphine−borane
8b according to route b, described above: yield 0.21 g, 25%; white
(s, CHarom), 127.4 (d, J = 5.2 Hz, CHarom), 127.2 (s, CHarom), 127.1 (s,
CHarom), 126.9 (s, CHarom), 126.8 (s, CHarom), 126.7 (s, CHarom), 125.4
(d, J = 12.0 Hz, CHarom), 124.3 (s, CHarom), 121.0 (s, CHarom), 120.9
(s, CHarom), 120.9 (s, CHarom), 119.9 (s, Carom), 109.0 (s, CHarom), 76.2
(s, CH2O, OPr), 75.7 (s, CH2O, OPr), 54.6 (s, CH3O), 29.9 (s,
ArCH2Ar), 29.8 (s, ArCH2Ar), 22.3 (s, CH2CH3, OPr), 22.2 (s,
CH2CH3, OPr), 22.2 (s, CH2CH3, OPr), 22.1 (s, CH2CH3, OPr), 9.2
(s, CH3, OPr), 9.1 (s, CH3, OPr). 31P NMR (CDCl3, 121 MHz): δ
−17.2.
25
crystals; mp 223−225 °C. [α]D = −27.0 (c 1, CHCl3). Rf = 0.6
1
(petroleum ether/AcOEt 8/2). H NMR (CDCl3, 300 MHz): δ 7.44
(m, 4H, CHarom), 7.36 (m, 1H, CHarom), 7.30 (m, 2H, CHarom), 7.16
(dd, 1H, J = 11.0, 2.0 Hz, CHarom), 7.09 (dd, 1H, J = 11.0, 2.0 Hz,
CHarom), 6.96 (m, 1H, CHarom), 6.91 (dd, 2H, J = 9.6, 7.1 Hz, CHarom),
6.78 (dd, 1H, J = 7.8, 3.7 Hz, CHarom), 6.30 (m, 4H, CHarom), 6.17 (m,
2H, CHarom), 4.35 (dd, 4H, J = 13.2, 2.7 Hz, ArCH2Ar), 3.87 (m, 4H,
OCH2, OPr), 3.64 (td, 4H, J = 7.0, 2.9 Hz, OCH2, OPr), 3.39 (s, 3H,
OCH3), 3.04 (d, 4H, J = 13.2 Hz, ArCH2Ar), 1.85 (m, 8H, CH2CH3,
OPr), 0.95 (t, 6H, J = 7.4 Hz, CH3, OPr), 0.8 (td, 6H, J = 7.4, 1.4 Hz,
CH3, OPr). 13C NMR (CDCl3, 75 MHz): δ 161.4 (s, Carom), 159.7 (d,
J = 2.6 Hz, Carom), 156.0 (s, Carom), 155.6 (s, Carom), 155.5 (s, Carom),
137.9 (d, J = 4.9 Hz, Carom), 136.5 (d, J = 4.7 Hz, Carom), 136.3 (d, J =
4.7 Hz, Carom), 135.8 (d, J = 11.2 Hz, Carom), 133.7 (s, Carom), 133.6 (s,
Carom), 133.5 (s, Carom), 133.5 (d, J = 30.7 Hz, Carom), 133.4 (s, Carom),
133.2 (s, Carom), 132.7 (s, Carom), 130.4 (s, Carom), 130.3 (d, J = 59.7
Hz, Carom), 130.3 (s, Carom), 128.2 (s, Carom), 128.1 (d, J = 7.2 Hz,
Carom), 127.9 (s, Carom), 127.7 (s, Carom), 126.5 (s, Carom), 122.3 (d, J =
1.9 Hz, Carom), 121.6 (d, J = 11.2 Hz, Carom), 121.1 (d, J = 63.0 Hz,
Carom), 117.9 (s, Carom), 117.5 (s, Carom), 111.4 (s, Carom), 77.3 (s,
CH2O, OPr), 76.9 (s, CH2O, OPr), 76.8 (s, CH2O, OPr), 55.1 (s,
OCH3), 30.9 (s, ArCH2Ar), 23.4 (s, CH2CH3, OPr), 23.3 (s, CH2CH3,
OPr), 23.2 (s, CH2CH3, OPr), 23.0 (s, CH2CH3, OPr), 10.6 (s, CH3,
OPr), 10.6 (s, CH3, OPr), 10.0 (s, CH3, OPr) 9.9 (s, CH3, OPr). 31P
NMR (CDCl3, 121 MHz): δ +17.3. HRMS (ESI-Q-TOF): calcd for
C53H61BClNaO5P [M + Na]+ 877.39304, found 877.39045. Anal.
Calcd for C53H61BClO5P (855.30): C, 74.43; H, 7.19. Found: C,
74.46; H, 7.30.
(S)-Ferrocenylphenyl{25,26,27,28-tetrapropoxycalix[4]arene}-
1
phosphine (5c): yield 0.86 g, 97%; orange solid. H NMR (CDCl3,
300 MHz): δ 7.26−7.16 (m, 5H, CHarom), 6.85−6.71 (m, 5H,
CHarom), 6.54−6.42 (m, 6H, CHarom), 4.43 (AX system, 4H,
ArCH2Ar), 4.31 (t, 2H, J = 1.8 Hz, Fc), 4.07 (s, 5H, Fc), 4.04 (t,
1H, J = 1.8 Hz, Fc), 3.96 (t, 1H, J = 1.8 Hz, Fc), 3.92 (m, 4H, CH2O,
OPr), 3.80 (m, 4H, CH2O, OPr), 3.14 (AX system, 4H, J = 13.2 Hz,
ArCH2Ar), 1.94 (m, 8H, CH2CH3, OPr), 0.98 (m, 8H, CH3, OPr). 13
C
NMR (CDCl3, 75 MHz): δ 157.6 (s, Carom), 156.8 (s, Carom), 156.1 (d,
J = 4.5 Hz, Carom), 140.2 (d, J = 9.8 Hz, Carom), 135.5 (s, Carom), 135.2
(d, J = 6.8 Hz, CHarom), 135.1 (s, CHarom), 134.7 (d, J = 4.5 Hz,
CHarom), 134.4 (d, J = 3.7 Hz, CHarom), 134.3 (s, CHarom), 133.9 (d, J =
12.1 Hz, CHarom), 133.6 (s, CHarom), 132.9 (d, J = 18.1 Hz, CHarom),
130.2 (d, J = 6.0 Hz, CHarom), 129.0 (s, CHarom), 128.4 (br.s, CHarom),
128.2 (s, CHarom), 128.0 (br.s, CHarom), 127.9 (s, CHarom), 127.8 (s,
CHarom), 122.1 (s, CHarom), 121.9 (s, CHarom), 76.8 (s, CH2O, OPr),
76.7 (s, CH2O, OPr), 73.1 (d, J = 18.1 Hz, Fc), 72.1 (d, J = 11.3 Hz,
Fc), 70.4 (d, J = 3.0 Hz, Fc), 70.3 (d, J = 4.5 Hz, Fc), 69.0 (br.s, Fc),
30.9 (br.s, ArCH2Ar), 23.3 (br.s, CH2CH3, OPr), 23.2 (s, CH2CH3,
OPr), 10.4 (s, CH3, OPr), 10.3 (s, CH3, OPr), 10.2 (s, CH3, OPr). 31
NMR (CDCl3, 121 MHz): δ −17.1.
P
(S,S)-5,17-Bis[(methylphenylphosphino)]{25,26,27,28-
1
tetrapropoxycalix[4]arene} (9a): yield 0.87 g, 97%; white solid. H
Preparation of Mono- and Diphosphines from Their Borane
Complexes. General Procedure. In a 50 mL two-necked flask
equipped with a magnetic stirrer and an argon inlet, 1 mmol of
monophosphine−borane 4a−c and 2 equiv of DABCO were dissolved
in 2 mL of toluene (in the case of 8a−c 4 equiv of DABCO were
used). The reaction mixture was heated to 50 °C for 12 h. After it was
cooled, the crude product was rapidly transferred via cannula into a
column previously evacuated and filled with argon containing neutral
alumina. The reaction solution was filtered using degassed dichloro-
methane as eluent. After removal of the solvent under vacuum/argon,
the free phosphine was obtained in excellent yield.
(S)-Methylphenyl{25,26,27,28-tetrapropoxycalix[4]arene}-
phosphine (5a): yield 0.70 g, 98%; white solid. 1H NMR (CDCl3, 300
MHz): δ 7.15−7.09 (m, 6H, CHarom), 6.67−6.45 (m, 10H, CHarom),
4.38 (AX system, 4H, J = 13.2 Hz, ArCH2Ar), 3.77 (m, 8H, CH2O,
OPr), 3.06 (AX system, 4H, J = 14.4 Hz, ArCH2Ar), 1.78 (m, 8H,
CH2CH3, OPr), 1.29 (d, 3H, J = 3.0 Hz, CH3P), 0.92 (m, 12H, CH3,
OPr). 13C NMR (CDCl3, 75 MHz): δ 156.4 (s, Carom), 155.3 (d, J =
12.8 Hz, Carom), 134.1 (br.s, Carom), 133.7 (d, J = 3.7 Hz, Carom), 131.6
(d, J = 21.9 Hz, CHarom), 131.1 (d, J = 17.4 Hz, CHarom), 130.6 (d, J =
18.1 Hz, CHarom), 127.1 (br.s, CHarom), 126.7 (s, CHarom), 122.0 (d, J =
3.0 Hz, CHarom), 75.8 (s, CH2O, OPr), 75.7 (s, CH2O, OPr), 75.6 (s,
CH2O, OPr), 29.9 (s, ArCH2Ar), 29.8 (s, ArCH2Ar), 22.3 (s, CH2CH3,
OPr), 22.2 (s, CH2CH3, OPr), 12.1 (d, J = 13.6 Hz, CH3P), 9.3 (s,
CH3, OPr). 31P NMR (CDCl3, 121 MHz): δ −27.8.
(S)-o-Anisylphenyl{25,26,27,28-tetrapropoxycalix[4]arene}-
phosphine (5b): yield 0.79 g, 98%; white solid. 1H NMR (CDCl3, 300
MHz): δ 7.16 (m, 2H, CHarom), 6.71 (m, 6H, CHarom), 6.53 (m, 1H,
CHarom), 6.34 (m, 6H, CHarom), 4.35 (AX system, 4H, J = 13.2 Hz,
ArCH2Ar), 3.85 (m, 4H, CH2O, OPr), 3.68 (m, 7H, CH2O and
CH3O), 3.02 (AX system, 4H, J = 13.2, 10.4 Hz, ArCH2Ar), 1.85 (m,
8H, CH2CH3, OPr), 0.91 (m, 12H, CH3, OPr). 13C NMR (CDCl3, 75
MHz): δ 160.0 (d, J = 14.8 Hz, Carom), 156.4 (d, J = 73.8 Hz, Carom),
154.9 (s, Carom), 154.8 (s, Carom), 136.8 (s, Carom), 136.2 (s, Carom),
136.1 (s, Carom), 135.0 (s, CHarom), 134.9 (d, J = 2.4 Hz, CHarom), 134.8
(d, J = 2.7 Hz, CHarom), 133.7 (s, CHarom), 133.5 (s, CHarom), 133.3 (s,
CHarom), 133.3 (s, CHarom), 133.0 (d, J = 1.3 Hz, CHarom), 132.5 (s,
CHarom), 132.5 (s, CHarom), 132.2 (s, CHarom), 129.1 (s, CHarom), 128.0
NMR (CDCl3, 300 MHz): δ 7.27−7.01 (m, 14H, CHarom), 6.19 (t,
2H, J = 7.2 Hz, CHarom), 6.07 (m, 4H, CHarom), 4.34 (AX system, 4H, J
= 13.2 Hz, ArCH2Ar), 3.93 (m, 4H, CH2O, OPr), 3.59 (t, 4H, J = 6.9
Hz, CH2O, OPr), 3.03 (AX system, 4H, J = 13.5 Hz, ArCH2Ar), 1.92−
1.76 (m, 8H, CH2CH3), 1.57 (d, 6H, J = 3.3 Hz, CH3P), 0.99 (t, 6H, J
= 7.2 Hz, CH3, OPr), 0.83 (t, 6H, J = 7.5 Hz, CH3, OPr). 13C NMR
(CDCl3, 75 MHz): δ 158.6 (s, Carom), 155.3 (s, Carom), 137.9 (s, Carom),
136.9 (d, J = 6.8 Hz, CHarom), 136.8 (d, J = 7.5 Hz, CHarom), 133.2 (d, J
= 8.3 Hz, CHarom), 131.6 (d, J = 18.1 Hz, CHarom), 129.1 (s, CHarom),
128.2 (s, CHarom), 128.1 (s, CHarom), 127.8 (s, CHarom), 127.5 (d, J =
3.8 Hz, CHarom), 125.3 (s, CHarom), 122.1 (s, Carom), 77.2 (s, CH2O,
OPr), 76.9 (s, CH2O, OPr), 30.9 (s, ArCH2Ar), 23.5 (s, CH2CH3,
OPr), 23.1 (s, CH2CH3, OPr), 13.0 (d, J = 6.0 Hz, CH3P), 10.8 (s,
CH3, OPr), 9.9 (s, CH3, OPr). 31P NMR (CDCl3, 121 MHz): δ −28.0.
The enantiomeric excess of 9a was determined by comparison with
a racemic sample, by 31P NMR in the presence of (+)-di-μ-
chlorobis{2[1-(dimethylamino)ethyl]phenyl-C,N}dipalladium (12).
31P NMR (CDCl3, 121 MHz): δ +26.0.
(S,S)-5,17-Bis[(o-anisylphenylphosphino)]{25,26,27,28-
1
tetrapropoxycalix[4]arene} (9b): yield 1.05 g, 98%; white solid. H
NMR (CDCl3, 300 MHz): δ 7.27 (m, 11H, CHarom), 7.11−7.05 (m,
3H, CHarom), 6.90−6.80 (m, 6H, CHarom), 6.76−6.62 (m, 2H, CHarom),
6.16 (t, 2H, J = 6.0 Hz, CHarom), 6.03−5.95 (m, 4H, CHarom), 4.32
(AX system, 4H, J = 12.0 Hz, ArCH2Ar), 3.96 (t, 4H, J = 9.0 Hz,
CH2O, OPr), 3.71 (s, 6H, CH3O), 3.51 (t, 4H, J = 6.0 Hz, CH2O,
OPr), 2.96 (AX system, 4H, J = 12.0 Hz, ArCH2Ar), 1.89 (m, 4H,
CH2CH3, OPr), 1.74 (m, 4H, CH2CH3, OPr), 0.98 (t, 6H, J = 9.0 Hz,
CH3, OPr), 0.82 (t, 6H, J = 9.0 Hz, CH3, OPr). 13C NMR (CDCl3, 75
MHz): δ 161.1 (d, J = 15.8 Hz, Carom), 158.8 (s, Carom), 155.1 (s,
Carom), 137.6 (d, J = 10.6 Hz, Carom), 137.3 (d, J = 6.5 Hz, Carom), 137.1
(d, J = 9.5 Hz, Carom), 135.2 (d, J = 26.7 Hz, CHarom), 134.7 (d, J = 15.8
Hz, CHarom), 133.8 (s, CHarom), 133.5 (d, J = 3.0 Hz, CHarom), 132.9 (s,
Carom), 130.1 (s, CHarom), 129.0 (s, CHarom), 128.5 (d, J = 7.5 Hz,
Carom), 128.3 (br.s, CHarom), 128.2 (d, J = 2.5 Hz, CHarom), 127.4 (d, J
= 6.2 Hz, CHarom), 126.9 (d, J = 13.0 Hz, Carom), 125.3 (s, CHarom),
121.3 (d, J = 65.7 Hz, CHarom), 110.1 (s, CHarom), 76.9 (s, CH2O,
OPr), 76.4 (s, CH2O, OPr), 55.6 (s, CH3O), 30.8 (s, ArCH2Ar), 23.4
J
dx.doi.org/10.1021/om400229p | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
(s, CH2CH3, OPr), 23.1 (s, CH2CH3, OPr), 10.8 (s, CH3, OPr), 9.8 (s,
CH3, OPr), 31P NMR (CDCl3, 121 MHz): δ −17.3.
The enantiomeric excess of 9b was determined by comparison with
a racemic sample, by 31P NMR in the presence of (+)-di-μ-
chlorobis{2[1-(dimethylamino)ethyl]phenyl-C,N}dipalladium (12).
31P NMR (CDCl3, 125 MHz): δ +31.5.
ASSOCIATED CONTENT
* Supporting Information
Figures giving NMR spectra and tables and CIF files giving
crystallographic data for (R)-4b, (S)-4c, (S,S)-8c, and (S)-11.
This material is available free of charge via the Internet at
http://pubs.acs.org.
■
S
(S,S)-5,17-Bis[(ferrocenylphenylphosphino)]{25,26,27,28-
1
tetrapropoxycalix[4]arene} (9c): yield 1.16 g, 99%; orange solid. H
AUTHOR INFORMATION
Corresponding Author
*S.J.: e-mail, Sylvain.juge@u-bourgogne.fr; tel. +33 (0)3 80 39
61 13. P.D.H.: e-mail, Pierre.Harvey@USherbrooke; tel, 1-819-
821-7092.
NMR (CDCl3, 300 MHz): δ 7.38−7.13 (m, 14H, CHarom), 6.27 (t,
2H, J = 7.8 Hz, CHarom), 6.12 (t, 4H, J = 7.8 Hz, CHarom), 4.23 (AX
system, 8H, ArCH2Ar and Fc), 4.27 (m, 2H, Fc), 4.18 (m, 2H, Fc),
4.15 (br.s, 10H, Fc), 4.05 (m, 4H, CH2O, OPr), 3.64 (t, 4H, J = 6.6
Hz, CH2O, OPr), 3.11 (AX system, 4H, J = 13.5 Hz, ArCH2Ar), 2.01−
1.93 (m, 4H, CH2CH3, OPr), 1.89−1.82 (m, 4H, CH2CH3, OPr), 1.08
■
(t, 6H, J = 7.2 Hz, CH3, OPr), 0.92 (t, 6H, J = 7.5 Hz, CH3, OPr). 13
C
Present Address
§Universite
́
Mentouri de Constantine, Facultes
Exactes, Dep
́
des Sciences
NMR (CDCl3, 75 MHz): δ 158.8 (s, Carom), 155.1 (s, Carom), 140.6 (d,
J = 10.6 Hz, Carom), 136.8 (d, J = 6.0 Hz, Carom), 134.8 (d, J = 12.1 Hz,
CHarom), 134.5 (d, J = 8.3 Hz, CHarom), 133.0 (br.s, CHarom), 132.8 (s,
CHarom), 130.7 (d, J = 6.8 Hz, Carom), 129.0 (s, CHarom), 128.2 (s,
CHarom), 128.0 (s, CHarom), 127.9 (d, J = 3.0 Hz, CHarom), 127.4 (d, J =
3.8 Hz, CHarom), 125.3 (s, CHarom), 121.9 (s, CHarom), 75.9 (s, CH2O,
OPr), 76.4 (s, CH2O, OPr), 73.4 (d, J = 17.3 Hz, Fc), 72.2 (d, J = 11.3
Hz, Fc), 70.6 (d, J = 3.6 Hz, Fc), 70.4 (d, J = 5.1 Hz, Fc), 69.1 (br.s,
Fc), 31.0 (s, ArCH2Ar), 23.5 (s, CH2CH3, OPr), 23.1 (s, CH2CH3,
OPr), 10.8 (s, CH3, OPr), 9.9 (s, CH3, OPr). 31P NMR (CDCl3, 121
MHz): δ −17.3.
̈
́
artement de Chimie, Route de Ain El bey,
Constantine 25000, Algeria.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
This research was supported by the CNRS (Centre National de
la Recherche Scientifique), the “Minister
National et de la Recherche”, the Natural Sciences and
Engineering Research Council of Canada (NSERC), and
Synthelor SA (Nancy). S.J. and P.D.H. are grateful to the
Agence Nationale de la Recherche for funding (ANR BLAN 07
MetChirPhos) and for an Excellence Research Chair held in
Dijon. We also thanks M. J. Penouilh and F. Picquet at the
■
̀
e de l’Education
The enantiomeric excess of 9c was determined by comparison with
a racemic sample, by 31P NMR in the presence of (+)-di-μ-
chlorobis{2[1-(dimethylamino)ethyl]phenyl-C,N}dipalladium (12).
31P NMR (CDCl3, 125 MHz): δ +32.7.
Typical Procedure for the Allylic Alkylation. A degassed
solution of [PdCl(η3-C3H5)]2 (0.003 g, 0.008 mmol) and the ligand
9a−c (0.016 mmol) (or 0.032 mmol of 5a) in dichloromethane (2
mL) was stirred for 30 min. Subsequently, a solution of (E)-1,3-
diphenylprop-2-en-1-yl acetate (0.202 g, 0.8 mmol) in dichloro-
methane (2 mL), dimethyl malonate (0.2 mL, 1.6 mmol), N,O-
bis(trimethylsilyl)acetamide (0.4 mL, 1.6 mmol), and a pinch of KOAc
were added. The reaction mixture was stirred at the desired
temperature. After the desired reaction time, the reaction mixture
was diluted with Et2O and saturated aqueous NH4Cl solution was
added. The mixture was extracted with Et2O, and the organic phases
were dried over MgSO4. The solvent was removed, and the conversion
̂ ́
Welience/Pole Chimie Moleculaire for the NMR and mass
spectrometry analyses.
REFERENCES
■
(1) (a) Tang, W.; Zhang, X. Chem. Rev. 2003, 103, 3029−3069.
(b) Guiry, P. J.; Saunders, C. P. Adv. Synth. Catal. 2004, 346, 497−537.
(c) Phosphorus Ligands in Asymmetric Catalysis; Borner, A.; Ed.; Wiley-
̈
VCH: Weinheim, Germany, 2008; Vols. 1−3. (d) Phosphorus(III)
Ligands in Homogeneous Catalysis: Design and Synthesis; Kamer, P. C. J.,
van Leeuwen, P. W. N. M., Eds.; Wiley: Chichester, U.K., 2012.
(2) (a) Asymmetric Catalysis on Industrial Scale; Blaser, H. U.,
Schmidt, E.; Eds.; Wiley-VCH: Weinheim, Germany, 2003. (b) Ager,
D. J.; de Vries, A. H. M.; de Vries, J. G. Chem. Soc. Rev. 2012, 41,
3340−3380. (c) Etayo, P.; Vidal-Ferran, A. Chem. Soc. Rev. 2013, 42,
728−754.
1
was measured by H NMR. The enantiomeric excess was determined
by HPLC on a chiral column (Chiralpak AD, hexane/i-PrOH 90/10,
0.5 mL/min, tR(R) = 21.5 min, tR(S) = 30.3 min), after purification by
flash column chromatography on silica gel using petroleum ether/ethyl
acetate 10/1 as eluent. 1H NMR (300 MHz, CDCl3): δ 7.33−7.18 (m,
10H, CHarom), 6.48 (d, 1H, J = 16.0 Hz, CH), 6.33 (dd, 1H, J = 8.2,
16.0 Hz, CH), 4.27 (dd, 1H, J = 8.2, 11.2 Hz, CH), 3.96 (d, 1H, J =
11.2 Hz, CH), 3.70 (s, 3H, CH3), 3.52 (s, 3H, CH3).
(3) (a) Juge,
Carreira, E., Yamamoto, H., Eds.; Elsevier: Amsterdam, 2012; Vol. 3,
pp 528−559. (b) Bayardon, J.; Juge, S. P-Chiral Ligands. In ref 1d , pp
355−389.
́
S.; Malacea, R.; Tessier. A. In Comprehensive Chirality;
́
Typical Procedure for the Allylic Amination. A degassed
solution of [PdCl(η3-C3H5)]2 (0.002 g, 0.005 mmol) and ligand 9a,b
(0.012 mmol) (or 0.024 mmol of ligand 5a,b) in dichloromethane (2
mL) was stirred for 30 min. Subsequently, a solution of (E)-1,3-
diphenylprop-2-en-1-yl acetate (0.125 g, 0.5 mmol) in dichloro-
methane (2 mL) and benzylamine (0.158 mL, 1.45 mmol) were
added. The reaction mixture was stirred at the desired temperature.
After the desired reaction time, the mixture was diluted with Et2O and
saturated aqueous NH4Cl solution was added. The mixture was
extracted with Et2O, and the organic phases were dried over MgSO4.
(4) (a) Gridnev, I. D.; Imamoto, T. Acc. Chem. Res. 2004, 37, 633−
644. (b) Gridnev, I. D.; Imamoto, T.; Hoge, G.; Kouchi, M.;
Takahashi, H. J. Am. Chem. Soc. 2008, 130, 2560−2572. (b) Gridnev, I.
D.; Imamoto, T. Chem. Commun. 2009, 7447−7464. (c) Imamoto, T.;
Tamura, K.; Zhang, Z.; Horiuchi, Y.; Sugiya, M.; Yoshida, K.;
Yanagisawa, A.; Gridnev, I. D. J. Am. Chem. Soc. 2011, 134, 1754−
1769.
(5) Darcel, C.; Moulin, D.; Henry, J.-C.; Lagrelette, M.; Richard, P.;
Harvey, P. D.; Juge,
́
S. Eur. J. Org. Chem. 2007, 2078−2090.
1
The solvent was removed, and the conversion was measured by H
(6) (a) Crepy, K. V. L; Imamoto, T. Adv. Synth. Catal. 2003, 345,
́
NMR. The enantiomeric excess was determined by HPLC on a chiral
column (Chiralcel OD-H, hexane/i-PrOH 99/1, 0.5 mL/min, tR(R) =
40.2 min, tR(S) = 44.3 min), after purification by flash column
chromatography on silica gel using n-hexane/ethyl acetate 8/2 as
eluent. 1H NMR (300 MHz, CDCl3): δ 7.52−7.13 (m, 15H, CHarom),
6.58 (d, 1H, J = 15.8 Hz, CH), 6.32 (dd, 1H, J = 7.6, 15.8 Hz,
CH), 4.40 (d, 1H, J = 7.6 Hz, CH), 3.79 (d, 1H, J = 13.2 Hz,
CH2N), 3.77 (d, 1H, J = 13.2 Hz, CH2N), 1.70 (s, 1H, HN).
79−101. (b) Oohara, N.; Katagiri, K.; Imamoto, T. Tetrahedron:
Asymmetry 2003, 14, 2171−2175. (c) Imamoto, T.; Sugita, K.;
Yoshida, K. J. Am. Chem. Soc. 2005, 127, 11934−11935. (d) Imamoto,
T.; Itoh, T.; Yamanoi, Y.; Narui, R.; Yoshida, K. Tetrahedron:
Asymmetry 2006, 17, 560−565. (e) Imamoto, T.; Nishimura, M.;
Koide, A.; Yoshida, K. J. Org. Chem. 2007, 72, 7413−7416.
(f) Imamoto, T.; Saitoh, Y.; Koide, A.; Ogura, T.; Yoshida, K.
Angew. Chem., Int. Ed. 2007, 46, 8636−8639. (g) Ogura, T.; Yoshida,
K
dx.doi.org/10.1021/om400229p | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
K.; Yangisawa, A.; Imamoto, I. Org. Lett. 2009, 11, 2245−2248.
(h) Tamura, K.; Sugiya, M.; Yoshida, K.; Yanasigawa, A.; Imamoto, T.
Org. Lett. 2010, 12, 4400−4403.
(14) (a) Monnereau, L.; Sem
J. 2010, 16, 9237−9247. (b) Monnereau, L.; Sem
Chem. Commun. 2011, 47, 6626−6628.
́
eril, D.; Matt, D.; Toupet, L. Chem. Eur.
́
eril, D.; Matt, D.
(15) (a) Jeunesse, C.; Dieleman, C.; Steyer, S.; Matt, D. Dalton
Trans. 2001, 881−892. (b) Gibson, C.; Rebek, J., Jr. Org. Lett. 2002, 4,
1887−1890. (c) Gaeta, G.; De Rosa, M.; Fruilo, M.; Soriente, A.; Neri,
(7) (a) Knowles, W. S.; Sabacky, M. J.; Vineyard, B. D.; Weinkauff,
D. J. J. Am. Chem. Soc. 1975, 97, 2567−2568. (b) Maienza, F.; Worle,
̈
M.; Steffanut, P.; Mezzetti, A.; Spindler, F. Organometallics 1999, 18,
1041−1049. (c) Nettekoven, U.; Kamer, P. C. J.; van Leeuwen, P. W.
N. M.; Widhalm, M.; Spek, A. L.; Lutz, M. J. Org. Chem. 1999, 64,
3996−4004. (d) Nettekoven, U.; Widhalm, M.; Kalchhauser, H.;
Kamer, P. C. J.; van Leeuwen, P. W. N. M.; Lutz, M.; Spek, A. L. J. Org.
Chem. 2001, 66, 759−770. (e) Hoge, G.; Wu, H.-P.; Kissel, W. S.;
Pflum, D. A.; Greene, D. J.; Bao, J. J. Am. Chem. Soc. 2004, 126, 5966−
5967. (f) Zupancic, B.; Mohar, B.; Stephan, M. Org. Lett. 2010, 12,
3022−3025. (g) Huang, K.; Zhang, X.; Emge, T. J.; Hou, G.; Cao, B.;
Zhang, X. Chem. Commun. 2010, 46, 8555−8557.
́
P. Tetrahedron: Asymmetry 2005, 16, 2333−2340. (d) Semeril, D.;
Jeunesse, C.; Matt, D.; Toupet, L. Angew. Chem., Int. Ed. 2006, 45,
5810−5814. (e) Sarkar, A.; Nethaji, M.; Krishnamurthy, S. S. J.
Organomet. Chem. 2008, 693, 2097−2110.
(16) (a) Khiri, N.; Bertrand, E.; Ondel-Eymin, M. J.; Rousselin, Y.;
Bayardon, J.; Harvey, P. D.; Juge, S. Organometallics 2010, 29, 3622−
́
3631. (b) The (25,26,27,28-tetrapropoxycalix[4]aren-5-yl)lithium
reagent was prepared by metal−halide exchange from the 5-bromo
precursor, using sec-butyllithium.16a The preparation of this lithium
reagent can also be achieved using n-butyllithium, as reported in ref
10a.
(8) (a) Colby, E. A.; Jamison, T. F. J. Org. Chem. 2003, 68, 156−166.
(b) Grabulosa, A.; Muller, G.; Ordinas, J. I.; Mezzetti, A.; Maestro, M.
A.; Font-Bardia, M.; Solans, X. Organometallics 2005, 24, 4961−4673.
(c) Ito, H.; Ito, S.; Sasaki, Y.; Matsuura, K.; Sawamura, M. J. Am. Chem.
Soc. 2007, 129, 14856−14857. (d) Chen, I.-H.; Yin, L.; Itano, W.;
Kanai, M.; Shibasaki, M. J. Am. Chem. Soc. 2009, 131, 11664−11665.
(e) Shibata, Y.; Tanaka, K. J. Am. Chem. Soc. 2009, 131, 12552−12553.
(17) Chaux, F.; Frynas, S.; Laureano, H.; Salomon, C.; Morata, G.;
Auclair, M. L.; Stephan, M.; Merdes
J.; Henry, J. C.; Bayardon, J.; Darcel, C.; Juge,
1213−1226.
(18) (a) Kaloun, E. B.; Merdes
Organomet. Chem. 1997, 529, 455−463. (b) Bauduin, C.; Moulin, D.;
Kaloun, E. B.; Darcel, C.; Juge,
(19) Farrugia, L. ORTEP-3 for Windows - a version of ORTEP-III
with a Graphical User Interface (GUI). J. Appl. Crystallogr. 1997, 30 (5
Part 1), 565.
(20) (a) Flack, H. On enantiomorph-polarity estimation. Acta
Crystallogr., Sect. A 1983, 39 (6), 876−881. (b) Flack, H. D. Chiral and
achiral crystal structures. Helv. Chim. Acta 2003, 86 (4), 905−921.
(c) Flack, H. D.; Bernardinelli, G. Reporting and evaluating absolute-
structure and absolute-configuration determinations. J. Appl. Crystal-
logr. 2000, 33 (4), 1143−1148.
(21) (a) Tani, K.; Brown, L. D.; Ahmed, J.; Ibers, J. A.; Yokota, M.;
Nakamura, A.; Otsuka, S. J. Am. Chem. Soc. 1977, 99, 7876−7886.
(b) Ollis, W. D.; Rey, M.; Sutherland, I. O. J. Chem. Soc., Perkin Trans.
1 1983, 1009−1027. (c) Dunina, V. V.; Kuz’mina, L. G.; Kazakova, M.
Yu.; Grishin, Yu. K.; Veits, Yu. A.; Kazakova, E. I. Tetrahedron:
Asymmetry 1997, 8, 2537−2545.
(22) (a) Barloy, L.; Ramdeehul, S.; Osborn, J. A.; Carlotti, C.;
Taulelle, F.; De Cian, A.; Fischer, J. Eur. J. Inorg. Chem. 2000, 2523−
2532. (b) Kollmar, M.; Helmchen, G. Organometallics 2002, 21, 4771−
4775. (c) Zhang, J.; Braunstein, P.; Welter, R.. Inorg. Chem. 2004, 43,
4171−4177.
(23) Otwinowski, Z.; Minor, W.; Carter, C. W., Jr. Processing of X-
ray diffraction data collected in oscillation mode. Methods Enzymol.
1997, 276, 307−326.
(24) Altomare, A.; Cascarano, G.; Giacovazzo, C.; Guagliardi, A.
Completion and refinement of crystal structures with SIR92. J. Appl.
Crystallogr. 1993, 26 (3), 343−350.
(25) (a) Sheldrick, G. A short history of SHELX. Acta Crystallogr.,
Sect. A 2008, 64 (1), 112−122. (b) Sheldrick, G. M. SHELX-97,
Program for the Refinement of Crystal Structures; University of
̀
, R.; Richard, P.; Ondel-Eymin, M.
́
S. C. R. Chim. 2010, 12,
́
̂ ́
, R.; Genet, J. P.; Uziel, J.; Juge, S. J.
́
(f) Reves, M.; Ferrer, C.; Leon, T.; Doran, S.; Etayo, P.; Vidal-Ferran,
́
S. J. Org. Chem. 2003, 11, 4293−4301.
A.; Riera, A.; Verdaguer, X. Angew. Chem., Int. Ed. 2010, 49, 9452−
9455. (g) Leon, T.; Parera, M.; Roglans, A.; Riera, A.; Verdaguer, X.
Angew. Chem., Int. Ed. 2012, 51, 1−6. (h) Skoda, E. M.; Davis, G. C.;
Wipf, P. Org. Process Res. Dev. 2012, 16, 26−34.
(9) (a) Dieleman, D.; Marsol, C.; Matt, D.; Kyritsakas, N.; Harriman,
A.; Kintzinger, J. -P. J. Chem. Soc., Dalton Trans. 1999, 4139−4148.
(b) Calixarenes: An Introduction ; Gutsche, C. D. in Monographs in
Supramolecular Chemistry; Stoddart, J. F., Ed.; RSC: Cambridge. U.K.,
2008. (c) Homden, D. M.; Redshaw, C. Chem. Rev. 2008, 108, 5086−
5130. (d) Calixarenes and Resorcinarenes: Synthesis, Properties and
Applications; Sliwa, W., Kozlowski, C., Eds.; Wiley-VCH: Weinheim,
Germany, 2009. (e) Siddiqui, S.; Cragg, P. J. Mini-Rev. Org. Chem.
2009, 6, 283−299. (f) Gramage-Doria, R.; Armspach, D.; Matt, D.
Coord. Chem. Rev. 2013, 257, 776−816.
́
(10) (a) Vezina, M.; Gagnon, J.; Villeneuve, K.; Drouin, M.; Harvey,
P. D. Organometallics 2001, 20, 273−281. (b) Lejeune, M.; Jeunesse,
C.; Matt, D.; Kyritsakas, N.; Welter, R.; Kintzinger, J. P. Dalton Trans.
2002, 1642−1650. (c) Lai, S.-W.; Chan, Q. K.-W.; Zhi, Y.-G.; Zhu, N.;
Che, C.-M. Organometallics 2009, 28, 34−37. (d) Over, D.; de la
Lande, A.; Zeng, X.; Parisel, O.; Reinaud, O. Inorg. Chem. 2009, 48,
4317−4330. (e) Sameni, S.; Lejeune, M.; Jeunesse, C.; Matt, D.;
Welter, R. Dalton Trans. 2009, 7912−7923.
(11) (a) Csok
́
, Z.; Szalontai, G.; Czira, G.; Kollar
́
, L. J. Organomet.
Chem. 1998, 570, 23−29. (b) Paciello, R.; Siggel, L.; Roper, M. Angew.
̈
Chem., Int. Ed. 1999, 38, 1920−1923. (c) Cobley, C. J.; Ellis, D. D.;
Orpen, A. G.; Pringle, P. G. Dalton Trans. 2000, 1109−1112.
(d) Parlevliet, F. J.; Kiener, C.; Fraanje, J.; Goubitz, K.; Lutz, M.; Spek,
A. L.; Kamer, P. C. J.; van Leewen, P. W. N. M. Dalton Trans. 2000,
1113−1122. (e) Shirakawa, S.; Shimizu, S.; Sasaki, Y. New J. Chem.
2001, 25, 777−779. (f) Kunze, C.; Selent, D.; Neda, I.; Schmutzler, R.;
Gottingen, Gottingen, Germany, 1997.
̈
̈
(26) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.;
Robb, M. A.; Cheeseman, J. R.; Zakrzewski, V. G.; Montgomery Jr., J.
A.; Stratmann, R. E.; Burant, J. C.; Dapprich, S.; Millam, J. M.; Daniels,
A. D.; Kudin, K. N.; Strain, M. C.; Farkas, O.; Tomasi, J.; Barone, V.;
Cossi, M.; Cammi, R.; Mennucci, B.; Pomelli, C.; Adamo, C.; Clifford,
S.; Ochterski, J.; Petersson, G. A.; Ayala, P. Y.; Cui, Q.; Morokuma, K.;
Malick, D. K.; Rabuck, A. D.; Raghavachari, K.; Foresman, J. B.;
Cioslowski, J.; Ortiz, J. V.; Baboul, A. G.; Stefanov, B. B.; Liu, G.;
Liashenko, A.; Piskorz, P.; Komaromi, I.; Gomperts, R.; Martin, R. L.;
Fox, D. J.; Keith, T.; Al-Laham, M. A.; Peng, C. Y.; Nanayakkara, A.;
Gonzalez, C.; Challacombe, M.; Gill, P. M. W.; Johnson, B. G.; Chen,
W.; Wong, M. W.; Andres, J. L.; Head-Gordon, M.; Replogle, E. S.;
Pople, J. A. Gaussian 98 (Revision A.6); Gaussian, Inc., Pittsburgh, PA,
1998.
Spannenberg, A.; Borner, A. Heteroat. Chem. 2001, 12, 577−585.
̈
(g) Steyer, S.; Jeunesse, C.; Matt, D.; Welter, R.; Wesolek, M. J. Chem.
Soc., Dalton Trans. 2002, 4264−4274. (h) Plourdre, F.; Gilbert, K.;
Gagnon, J.; Harvey, P. D. Organometallics 2003, 22, 2862−2875.
(i) Sem
7155. (j) Monnereau, L.; Sem
Catal. 2009, 351, 1629−1636.
(12) (a) Parlevliet, F. J.; Zuideveld, M. A.; Kiener, C.; Kooijman, H.;
́
eril, D.; Matt, D.; Toupet, L. Chem. Eur. J. 2008, 14, 7144−
́
eril, D.; Matt, D.; Toupet, L. Adv. Synth.
Spek, A. L.; Kamer, P. C. J.; van Leeuwen, P. W. N. M. Organometallics
1999, 18, 3394−3405. (b) Sem
́
eril, D.; Jeunesse, C.; Matt, D. C. R.
Chim. 2008, 11, 583−594.
(13) (a) Dieleman, C.; Steyer, S.; Jeunesse, C.; Matt, D. Dalton
Trans. 2001, 2508−2517. (b) Marson, A.; Freixa, Z.; Kamer, P. C. J.;
van Leeuwen, P. W. N. M. Eur. J. Inorg. Chem. 2007, 4587−4591.
(27) Hohenberg, P.; Kohn, W. Phys. Rev. 1964, 136, B864−B871.
L
dx.doi.org/10.1021/om400229p | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
(28) Kohn, W.; Sham, L. J. Phys. Rev. 1965, 140, A1133−A1138.
(29) The Challenge of d and f Electrons; Salahub, D. R., Zerner, M. C.,
Eds.; American Chemical Society: Washington, DC, 1989.
(30) Parr, R. G.; Yang, W. Density-Functional Theory of Atoms and
Molecules; Oxford University Press: Oxford, U.K., 1989.
(31) Becke, A. D. J. Chem. Phys. 1993, 98, 5648−5652.
(32) Lee, C.; Yang, W.; Parr, R. G. Phys. Rev. B: Condens. Matter
Mater. Phys. 1988, 785−789.
(33) Miehlich, B.; Savin, A.; Stoll, H.; Preuss, H. Chem. Phys. Lett.
1989, 157, 200−206.
(34) Binkley, J. S.; Pople, J. A.; Hehre, W. J. J. Am. Chem. Soc. 1980,
102, 939−947.
(35) Gordon, M. S.; Binkley, J. S.; Pople, J. A.; Pietro, W. J.; Hehre,
W. J. J. Am. Chem. Soc. 1982, 104, 2797−2803.
(36) Pietro, W. J.; Francl, M. M.; Hehre, W. J.; Defrees, D. J.; Pople,
J. A.; Binkley, J. S. J. Am. Chem. Soc. 1982, 104, 5039−5048.
(37) Dobbs, K. D.; Hehre, W. J. J. Comput. Chem. 1986, 7, 359−378.
(38) Dobbs, K. D.; Hehre, W. J. J. Comput. Chem. 1987, 8, 861−879.
(39) Dobbs, K. D.; Hehre, W. J. J. Comput. Chem. 1987, 8, 880−893.
(40) SBKJC ECP/VDZ Basis Set Exchange Library; https://bse.pnl.
gov/bse/portal.
(41) Stevens, W. J.; Basch, H.; Krauss, M. J. Chem. Phys. 1984, 81,
6026−6033.
(42) Stevens, W. J.; Krauss, M.; Basch, H.; Jasien, P. G. Can. J. Chem.
1992, 70, 612−630.
(43) Cundari, T. R.; Stevens, W. J. J. Chem. Phys. 1993, 98, 5555−
5565.
M
dx.doi.org/10.1021/om400229p | Organometallics XXXX, XXX, XXX−XXX