Theoretical and Experimental Optimization of a New Amino Phosphite Ligand Library for Asymmetric Palladium-Catalyzed Allylic Substitution

Article abstract of DOI:10.1002/cctc.201500873

A new library of modular amino phosphite ligands obtained in a few synthetic steps from enantiopure amino alcohols has been tested in asymmetric Pd-catalyzed allylic substitution. The modular ligand design is crucial to find highly selective catalysts for each substrate type using a wide range of C-, N-, and O-nucleophiles. A DFT study of the species responsible for the enantiocontrol was used to optimize the ligand structure. By selecting the ligand components, we were able to identify unprecedented catalytic systems that can create new chiral C-C, C-N, and C-O bonds in a variety of substrate types (hindered and unhindered) in high yields and enantioselectivities (ee values up to 99 %). Further studies on the Pd-π-allyl intermediates provided a deep understanding of the effect of ligand structure in the origin of enantioselectivity. Potential applications of the new Pd/amino phosphite catalysts were demonstrated by the practical synthesis of a range of chiral carbocycles by simple tandem reactions, with no loss of enantioselectivity.

Full text of DOI:10.1002/cctc.201500873

DOI: 10.1002/cctc.201500873
Full Papers
Theoretical and Experimental Optimization of a New
Amino Phosphite Ligand Library for Asymmetric
Palladium-Catalyzed Allylic Substitution
Marc Magre,[a] Maria Biosca,[a] Per-Ola Norrby,*[b, c] Oscar Pàmies,*[a] and
Montserrat DiØguez*[a]
A new library of modular amino phosphite ligands obtained in
a few synthetic steps from enantiopure amino alcohols has
been tested in asymmetric Pd-catalyzed allylic substitution.
The modular ligand design is crucial to find highly selective
catalysts for each substrate type using a wide range of C-, N-,
and O-nucleophiles. A DFT study of the species responsible for
the enantiocontrol was used to optimize the ligand structure.
By selecting the ligand components, we were able to identify
unprecedented catalytic systems that can create new chiral
CÀC, CÀN, and CÀO bonds in a variety of substrate types (hin-
dered and unhindered) in high yields and enantioselectivities
(ee values up to 99%). Further studies on the Pd-p-allyl inter-
mediates provided a deep understanding of the effect of
ligand structure in the origin of enantioselectivity. Potential ap-
plications of the new Pd/amino phosphite catalysts were dem-
onstrated by the practical synthesis of a range of chiral carbo-
cycles by simple tandem reactions, with no loss of enantiose-
lectivity.
Introduction
The syntheses of chiral CÀX bonds, in which X is C or a hetero-
atom, are the most significant processes in the preparation of
complex chiral molecules from simple ones. Of the CÀX bond-
forming strategies, enantioselective Pd-catalyzed allylic substi-
tution is among the most studied. Some advantages include
a high functional group tolerance, mild reaction conditions,
and high versatility of the alkene functionality of the substrate
for further stereoselective functionalization.[1] Most of the best
ligands reported to date for Pd-catalyzed allylic substitution
use the capacity of the ligand to direct the nucleophilic attack
to one of the allylic terminal atoms by either a secondary
ligand–nucleophile interaction[2] or electronic discrimination.[1,3]
The latter approach uses heterodonor ligands to differentiate
electronically between the two allylic terminal C atoms be-
cause of the different trans influences of the donor groups.
Mixed phosphine/phosphinite oxazoline ligands have played
a dominant role as heterodonors.[1] Our group has contributed
to Pd-catalyzed allylic substitution by the improved generation
of ligands. We have shown that some common limitations of
this process, such as low reaction rates and high substrate spe-
cificity, are overcome by the introduction of biaryl phosphite
moieties into the ligand design.[4] As a result, increased reac-
tion rates are achieved thanks to the higher p-acceptor ability
of the phosphite groups and substrate versatility is increased
because the flexibility of the phosphite moieties allows the cat-
alyst chiral pocket to adapt to both hindered and unhindered
substrates. Therefore, we have reported several phosphite oxa-
zolines as extremely effective ligands for this process.[5] Despite
the important advances, the application of phosphite oxazo-
line ligands is mainly limited to the use of a few nucleophiles,
mainly dimethyl malonate and benzylamine. The use of func-
tionalized malonates and alkyl alcohols is little reported.[1] In
addition, only a few catalysts have been applied efficiently in
the allylic substitution of several types of substrates with differ-
ent electronic and steric proprieties using a broad range of nu-
cleophiles.[6] Therefore, more effort should be made to expand
this range of nucleophiles and substrates with the aim to syn-
thesize more complex chiral organic molecules.
[a] M. Magre, M. Biosca, Dr. O. Pàmies, Prof. M. DiØguez
Departament de Química Física i Inorgànica
Universitat Rovira i Virgili
C/Marcel·li Domingo, s/n. 43007 Tarragona (Spain)
E-mail: oscar.pamies@urv.cat
montserrat.dieguez@urv.cat
To expand the range of ligands and improve performance,
we have moved our research towards the development of het-
erodonor ligands that contain groups more robust than oxazo-
lines. In this context, we reported the application of Pd/phos-
phite pyridine/thioether catalytic systems in the allylic substitu-
tion of several substrate types using a large variety of nucleo-
philes.[7] Apart from this, the successful use in this process of
other heterodonor P-X ligands, in which X is a more robust
group than oxazoline, has not been reported yet, and a system-
atic study of the scope of this family of ligands is still missing.
[b] Prof. P.-O. Norrby
Pharmaceutical Development, Global Medicines Development
AstraZeneca
Pepparedsleden 1, SE-431 83 Mçlndal (Sweden)
Per-Ola.Norrby@astrazeneca.com
[c] Prof. P.-O. Norrby
Department of Chemistry
University of Gothenburg
Kemigården 4, SE-412 96 Gçteborg (Sweden)
Supporting information and ORCID(s) from the author(s) for this article is
available on the WWW under http://dx.doi.org/10.1002/cctc.201500873.
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Although other researchers have developed heterodonor phos-
phine/phosphinite ligands that contain groups more robust
than oxazoline (such as amine,[8] imine,[9] pyridine,[10] and thio-
ether[11]), only a few of them have been applied successfully
and these are limited in substrate and nucleophile scope
(enantioselectivities are mainly high in the allylic substitution
of the hindered standard substrate rac-1,3-diphenyl-3-acetoxy-
prop-1-ene (S1) using dimethyl malonate as the nucleophile).
To be of practical interest, substantial improvements in terms
of enantioselectivity, chemical yield, and substrate and nucleo-
phile versatility are still needed.
To address this point, in this study we prepared and tested
a new family of chiral ligands that are readily accessible, easy
to handle, and expand the application range. We report
a highly modular amino phosphite ligand library (Figure 1) for
Scheme 1. Synthesis of amino phosphites L1–L6a–g. a) Formic acid/para-
formaldehyde/H2O (yields 90–95%);[12] b) 2,2-dimethoxypropane/toluene
(yield 72%);[13] c) MeMgBr/Et2O or PhMgBr/THF (yields 87–93%),[14] and
d) ClP(OR)2; (OR)2 =a–g/pyridine/toluene (yields 30–95%).
ciently understood to predict, a priori, the type of ligand
needed to obtain a high selectivity. To address this important
point, in this study we performed DFT calculations and the syn-
thesis and characterization of the Pd-p-allyl intermediates to
explain the origin of enantioselectivity using these highly ver-
satile catalytic systems. Notably, these DFT calculations have
been crucial to the optimization of the ligand design.
Results and Discussion
Synthesis of ligand library
Ligands L1–L6a–g were synthesized from the corresponding
easily accessible enantiopure amino alcohols (1–4; Scheme 1).
Amino alcohols 1–4 already incorporate the desired diversity
in the substituents and in the configurations of the backbone.
The diversity at the amino group was achieved by either direct
methylation of 1–4 using formic acid and formaldehyde to
afford 5–8[12] (Scheme 1, step a) or by the formation of oxazoli-
dine 9[13] (Scheme 1, step b) from 1, followed by ring-opening
with the corresponding Grignard reagents (10–11, step c).[14] Fi-
nally, the reaction of amino alcohols 5–8, 10, and 11 with one
equivalent of the desired phosphorochloridite formed in situ
gave access to amino phosphite ligands L1–L6a–g (step d)
with the desired substituents and configurations of the biaryl
phosphite group (a–g). Ligands L1–L6a–g were isolated in
moderate-to-good yields as white solids after purification on
neutral alumina under an Ar atmosphere. Advantageously,
they were stable in air and very stable to hydrolysis, so further
manipulation/storage was performed in air. The ESI-HRMS
spectra were in agreement with the assigned structures. Li-
gands L1–L6a–g were also characterized by 1H, 13C, and
31P NMR spectroscopy. The spectral assignments, made using
1H-1H and 13C-1H correlation measurements, were as expected
for these C1-symmetric ligands. One singlet for each compound
was observed in the 31P NMR spectra. Rapid ring inversions
(tropoisomerization) in the biphenyl phosphorus moieties (a–c)
occurred on the NMR timescale because the expected diaste-
Figure 1. Amino phosphite ligand library L1–L6a–g.
the Pd-catalyzed allylic substitution of hindered and unhin-
dered substrates with a large number of nucleophiles. These li-
gands are prepared easily in few steps from readily available
enantiopure amino alcohols. They also incorporate the advan-
tages of the robustness of the amine moiety and the addition-
al control provided by either the adaptability of the chiral
cavity because of the biaryl phosphite groups and the flexibili-
ty of the chiral pocket through a highly modular ligand scaf-
fold. In a simple two- or three-step procedure (Scheme 1), sev-
eral ligand parameters could be tuned easily to maximize the
catalyst performance so that we could investigate the effect of
the systematic change of the substituents (L1, L5, and L6) and
configuration (L1 and L4) at the ligand backbone, the amine
substituents (L1–L3) and the substituents and configurations
in the biaryl phosphite moiety (a–g). By a judicious choice of
ligand components, we achieved high enantioselectivities and
activities in a number of substrates using a wide range of C-,
N-, and O-nucleophiles. The potential application of these new
Pd/amino phosphite catalytic systems has been demonstrated
by the practical synthesis of chiral carbocycles by simple se-
quential reactions with no loss of ee.
Despite the recent success of Pd/phosphite-nitrogen catalyst
systems, the mechanistic aspects of these ligands are not suffi-
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reoisomers were not detected by low-temperature 31P NMR (in
CD2Cl2 +35 to À858C).[15]
Table 1. Pd-catalyzed allylic alkylation of S1–S2 with dimethyl malonate
as the nucleophile using ephedrine-based amino phosphite ligands L1–
L4a–g.[a]
Allylic substitution of rac-1,3-diphenyl-3-acetoxyprop-1-ene
(S1) and rac-3-acetoxycyclohexene (S2) with ephedrine-
based ligands L1–L4a–g: Computational study for ligand
optimization
Entry
Ligand
Conversion
(yield)
[%][b]
ee
Conversion
(yield)
[%][d]
ee
[%][c]
[%][e]
First, we tested the efficiency of the ephedrine-based amino
phosphite ligands L1–L4a–g. As mentioned previously, the
asymmetric Pd-catalyzed allylic alkylation is highly dependent
on the olefin geometry.[1] The effectiveness of the catalyst to
transfer the chiral information to the alkylated product de-
pends mainly on its ability to adapt to the variation of the
steric demands of the substrate. To assess the performance of
L1–L4a–g in the allylic alkylation of substrates with different
steric requirements, we evaluated them initially in the asym-
metric Pd-catalyzed allylic alkylation of the model substrates
S1 and rac-3-acetoxycyclohexene (S2) [Eq. (1)]. As a result of
the presence of less bulky anti substituents, the enantioselec-
tivity for cyclic S2 is more difficult to control.[1] There are,
therefore, fewer successful catalysts for S2. In all cases, the cat-
alysts were generated in situ from [PdCl(h3-C3H5)]2 and the cor-
responding ligand.
1
2
3
4
5
6
7
8
L1a
L1b
L1c
L1d
L1e
L1 f
L1g
L2a
L2d
L2e
L3a
L3d
L3e
L4a
L4d
L4e
100 (94)
100 (92)
51 (48)
100 (94)
100 (93)
50 (45)
36 (31)
29 (24)
100 (96)
70 (66)
56 (51)
100 (93)
84 (80)
62 (57)
100 (96)
89 (85)
31 (R)
29 (R)
11 (R)
81 (R)
75 (S)
64 (R)
27 (S)
6 (S)
42 (R)
33 (S)
0
42 (R)
29 (S)
8 (R)
100 (93)
100 (94)
98 (91)
100 (90)
100 (93)
95 (89)
9 (R)
8 (R)
3 (R)
60 (R)
60 (S)
39 (R)
58 (S)
9 (S)
36 (R)
56 (S)
9 (S)
53 (S)
68 (S)
7 (R)
45 (R)
70 (S)
97 (91)
100 (92)
100 (88)
100 (93)
100 (91)
100 (92)
100 (89)
100 (93)
100 (91)
100 (93)
9
10
11
12
13
14
15
16
81 (R)
60 (S)
[a] Reactions were performed at 238C with [PdCl(h3-C3H5)]2 (0.5 mol%),
ligand (1 mol%), CH2Cl2 as solvent, bis(trimethylsilyl)acetamide (BSA,
3 equiv.), dimethyl malonate (3 equiv.), KOAc (3 mg). [b] Conversions and
yields determined after 6 h. [c] ee determined by HPLC. [d] Conversions
and yields determined after 18 h. [e] ee determined by GC.
and L3 (i.e., entry 4 vs. 9 and 12). A plausible explanation may
be the formation of mixtures of diastereomeric amino com-
plexes with L2 and L3 (the N atom in L2 and L3 becomes a ste-
reogenic center upon coordination to the metal). In addition,
L1 have the advantage that they can be synthesized in fewer
steps than L2 and L3 (Scheme 1).
Finally, the configuration of the ephedrine backbone was
studied by comparing L1 and L4. A cooperative effect between
the configurations of both the ephedrine backbone and the
biaryl phosphite moiety was observed. Such a cooperative
effect depends of the steric demands of the substrate. Al-
though for S1 the cooperative effect results in a matched com-
bination for ligands L1d and L4d (81% ee, entries 4 and 15),
which contains an R-biphenyl moiety, the matched combina-
tion for substrate S2 was achieved using pseudoephedrine-
based ligand L4e (70% ee, entry 16), which contains an S-bi-
phenyl phosphite moiety.
The results summarized in Table 1 indicate that the enantio-
selectivity is mainly affected by the substituents/configuration
at the biaryl phosphite moiety (a–g) and by the amine sub-
stituents, whereas the configuration of the ephedrine back-
bone has less effect. Therefore, the enantioselectivity is con-
trolled mostly by the biaryl phosphite moiety, regardless of the
configuration of the ephedrine backbone. The effect of the
substituents/configuration of the biaryl phosphite moiety was
studied with L1a–g (Table 1, entries 1–7). The results indicate
that the presence of trimethylsilyl groups at the ortho positions
of the biaryl phosphite moiety affects both the activity and the
enantioselectivity negatively (entry 3 vs. 1–2 and entries 6–7
vs. 4–5). Also, if we compare the results of the use of L1a with
those of the related enantiopure biaryl ligands L1d and L1e
(entry 1 vs. 4 and 5), we can conclude that the tropoisomeric
biphenyl moiety in L1a–c is not controlled when coordinated
in the Pd-p-allyl intermediate species. The best enantioselectiv-
ities were obtained with ligands that contained enantiopure
biaryl phosphite moieties with tert-butyl groups at the ortho
positions (d and e; entries 4 and 5).
To identify which ligand parameters should be further modi-
fied to increase the enantioselectivity, we performed a DFT
computational study of the key intermediates and transition
states involved in the enantiocontrol of the Pd-catalyzed allylic
substitution of S1 using L4d and L4e as models. Previous
mechanistic studies have shown that enantioselectivity is con-
trolled in the effectively irreversible nucleophilic attack, but the
transition state (TS) for this step can be either early or late de-
pending on the nature of the nucleophile, ligands, and reac-
tion conditions. In an early TS, the interactions that lead to ste-
We then evaluated the effect of the amine substituents with
L1–L3. In general, the use of L1, which have a dimethyl amine
group, yielded higher enantioselectivities than the use of L2
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reochemical differentiation can be understood from the struc-
ture of the Pd-allyl intermediate,[16] whereas the late TS is more
reminiscent of the Pd-alkene product complex.[17] A sterically
encumbered ligand can be employed to push the allyl group
into a more product-like orientation, which affects the regio-
chemical preference in the nucleophilic attack strongly.[18] In
our experience, a diffuse anion such as malonate or a neutral
nucleophile such as amine would be expected to give relative-
ly early TSs, whereas a highly concentrated charge such as
a fluoride anion gives a late TS.[19]
Table 2. Calculated energies [kJmolÀ1] for the endo and exo Pd-h3-allyl in-
termediates, TSs, and Pd-p-olefin complexes using S1 and NH3 as nucleo-
phile.[a]
L4d
L4e
0
8.2
For the early TS case, the stereochemistry is governed by
both the population of the Pd-h3-allyl intermediates and the
relative electrophilicity of the allylic carbon atoms, and an allyl
terminus trans to a P atom is generally more reactive than one
trans to a N atom. If the TS is late, the formation of the most
stable Pd-olefin complex controls the enantioselectivity. Calcu-
lations were performed using the B3LYP functional, the
6-31G*/LANL2DZ basis set, and the polarizable continuum
model (PCM) for the solvent with parameters for CH2Cl2 as im-
plemented in Gaussian 09. The energies were further refined
by performing single-point calculations at the 6-311+G** level
and by dispersion correction with the DFT-D3 model. Previous
experience has shown us that ammonia can be used as a good
model nucleophile,[2b,20] which avoids the problems related to
charge separation in conjunction with a continuum solvent
model. Notably, the use of ammonia as the nucleophile instead
of dimethyl malonate results in the inversion of the Cahn–
Ingold–Prelog (CIP) descriptor in the 1,3-diphenylallyl case be-
cause of the change in the priority of the groups, although the
stereoselectivity is maintained.
Initially, we calculated the relative stability of the Pd-h3-di-
phenylallyl complexes. Only the two syn-syn h3-allyl complexes
(Pd-h3-endo and Pd-h3-exo, Table 2) were calculated. In accord-
ance with that already described in the literature, the contribu-
tion of the other allylic species of higher energy (anti-anti and
syn-anti Pd-h3) was neglected.[1d] In line with the catalytic re-
sults (Table 1), the DFT results indicate that the configuration
of the biaryl phosphite moiety controls the preferential forma-
tion of one of the syn-syn Pd-allyl intermediates. Thus, al-
though the formation of Pd-h3-exo is preferred for L4d (DG=
7.6 kJmolÀ1), the most stable Pd-allyl intermediate for L4e is
Pd-h3-endo (DG=8.2 kJmolÀ1). If we assume that the allyl inter-
mediates are in rapid equilibrium[21] and that the nucleophile
will always attack trans to the P atom, the preferred intermedi-
ate leads to the preferred product in this case.
7.6
0
2
0
0
4
0
0
5
1.8
achieved with L4e (DG# =5 kJmolÀ1 for L4e vs. 1.8 kJmolÀ1
for L4d). Thus, in this case, the product complex energies do
not correlate with the TS energies or with the experimental se-
lectivities. The structural elucidation of the Pd-allyl intermedi-
ates and the determination of their relative reactivity towards
the nucleophile are, therefore, crucial to understand their cata-
lytic behavior (see below).
The calculated TSs for the major and the minor pathways
with both ligands are shown in Figure 2. A special feature of
all these TSs is that the methyl substituent of the ephedrine
backbone points away from the coordination sphere. This sug-
gests that the methyl group should have little impact on the
enantioselectivity. To prove this, we recalculated the TSs by re-
moving the methyl substituent of the ephedrine backbone
(new ligand L5e; Figure 1). Surprisingly, the calculated energy
difference between the two TSs for the formation of both
enantiomers of the alkylated product (Figure 3a) was
8.5 kJmolÀ1 (L5e), which surpasses the values for L4d and L4e
(4 and 2 kJmolÀ1, respectively) and indicates that L5e should
provide a higher enantioselectivity than the ephedrine-based
ligands L4d and L4e.
We then calculated TSendo and TSexo using NH3 as the nucleo-
phile (Table 2). The energy differences of the calculated TSs
agree with the catalytic results. The energy difference between
the TSs of L4d (DG# =4 kJmolÀ1) is higher than that of L4e
(DG# =2 kJmolÀ1). This is in good agreement with the higher
enantioselectivities achieved using L4d (Table 1, 81% ee for
L4d vs. 60% ee for L4e). In addition, the formation of the op-
posite enantiomers of the substituted product is predicted if
L4d and L4e are used.
Finally, we calculated the Pd-olefin intermediates
(Pd-olefinendo and Pd-olefinexo). The results (Table 2) indicated
that a higher energy difference of the Pd-olefin complexes is
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Table 3. Pd-catalyzed allylic alkylation of S1 and S2 with dimethyl malo-
nate using amino phosphite ligands L5–L6d–e.[a]
Entry
Ligand
Conversion
(yield)
[%][b]
ee
Conversion
(yield)
[%][d]
ee
[%][c]
[%][e]
1
2
3
4
5[f]
6[g]
7[h]
L5d
L5e
L6d
L6e
L5e
L5e
L5e
100 (94)
100 (96)
100 (92)
100 (93)
100 (95)
98 (91)
92 (R)
94 (S)
41 (R)
62 (S)
97 (S)
92 (S)
89 (S)
100 (90)
100 (89)
100 (91)
100 (92)
100 (91)
94 (87)
70 (R)
82 (S)
46 (R)
62 (S)
86 (S)
83 (S)
74 (S)
38 (32)
56 (49)
[a] Reactions were performed at 238C with [PdCl(h3-C3H5)]2 (0.5 mol%),
ligand (1 mol%), CH2Cl2 as solvent, BSA (3 equiv.), dimethyl malonate
(3 equiv.), KOAc (3 mg). [b] Conversions and yields determined after 6 h.
[c] ee determined by HPLC. [d] Conversions and yields determined after
18 h. [e] ee determined by GC. [f] Reactions performed at 58C for 18 h.
[g] Reactions performed at 08C for 18 h. [h] Reactions performed at
À158C for 18 h.
Figure 2. Calculated transition states using ephedrine-based L4d and L4e.
be obtained by simply changing the configuration of the biaryl
phosphite moiety in L5. All these results show the importance
of using a modular scaffold to build new ligand systems.
The enantioselectivity can be improved by controlling not
only the structure but also the reaction parameters. Therefore,
we studied these reactions at a low reaction temperature (en-
tries 5–7). Enantioselectivity was further improved (ee values
up to 97% for S1 and 86% for S2) by decreasing the reaction
temperature to 58C (Table 3, entry 5).
Figure 3. Calculated energies of TSs using a) L5e and b) L6e.
Allylic substitution of symmetrical 1,3-disubstituted allylic
substrates S1–S10 with other C-, N-, and, O-nucleophiles:
Scope and limitations
To study the effect of the other stereogenic center of the
ephedrine backbone (C-2), the phenyl substituent was
switched from C-1 to C-2 (L6e; Figure 1). A slightly lower
energy difference between the TSs was achieved for Pd-L6e
than Pd-L4e (Figure 3b), which suggests that this modification
should provide lower enantioselectivities for L6e than L4e.
These theoretical results prompted us to prepare and screen
amino phosphite ligands L5–L6d–e (Scheme 1) for the asym-
metric allylic substitution of substrates S1 and S2 (Table 3). As
predicted by the theoretical calculations, the use of L5e, which
does not have the methyl substituent at the stereogenic C-2
position of the ephedrine backbone, in the allylic alkylation of
S1 provided the highest enantioselectivities (Table 3, entry 2,
94% (S) ee), whereas the use of L6e led to similar enantioselec-
tivities as that of L4e (entry 4). The same behavior is observed
in the allylic alkylation of cyclic S2. If we used L5e, we could,
therefore, increase the enantioselectivity from 70 to 82% ee
(Table 3, entry 2). Interestingly, for S1, ligand L5d provided
similarly high enantioselectivities as L5e but in the opposite
enantiomer of the substitution product (92% (R) ee, entry 1).
Both enantiomers of the substitution products can, therefore,
We investigated the substrate and nucleophile scope with the
optimal amino phosphite ligands L5e and L5d. The following
linear and cyclic disubstituted substrates with different steric
properties were studied [Eq. (2)]: S1, S2, rac-1,3-di(4-tolyl)-3-
acetoxyprop-1-ene (S3), rac-1,3-di(4-bromophenyl)-3-acetoxy-
prop-1-ene (S4), rac-1,3-di(3-methoxyphenyl)-3-acetoxyprop-1-
ene (S5), rac-1,3-di(2-tolyl)-3-acetoxyprop-1-ene (S6), rac-1,3-di-
methyl-3-acetoxyprop-1-ene (S7), rac-(E)-ethyl-2,5-dimethyl-3-
hex-4-enylcarbonate (S8), rac-3-acetoxycyclopentene (S9), and
rac-3-acetoxycycloheptene (S10). The range of nucleophiles
was also expanded compared to that of previous work, with
special attention paid to the more challenging and interesting
from a synthetic point of view, such as functionalized malo-
nates, b-diketones, and alkyl alcohols, which are seldom report-
ed.
The results of Pd/L5e and Pd/L5d in the allylic substitution
of S1 using a wide range of C-, N-, and O-nucleophiles are
shown in Table 4. The enantioselectivity was relatively unaffect-
ed by the change in the steric nature of the ester groups and
in the substituents of the malonate nucleophiles (entries 1–13).
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Therefore,
a variety of malo-
nates, which include those that
are a-substituted, reacted clean-
ly with S1 to afford products
14–20 in high yields and with
enantioselectivities that were as
high as or higher than those ob-
tained with dimethyl malonate
(ee values up to 99% ee; en-
tries 1–13). Among these are the
strikingly high enantioselectivi-
ties achieved using allyl-, buten-
yl, pentenyl-, and propargyl-sub-
stituted malonates (entries 7–13;
95–99% ee). This is advanta-
geous because the resulting
products are important precur-
sors for more complex chiral
Table 4. Allylic substitution of S1 with several C-, N-, and O-nucleophiles using Pd/L5d–e catalytic systems [see Eq. (2)].[a]
L5d
L5e
Entry
Nucleophile
Product
Yield
[%][b]
ee
[%][c]
Yield
[%][b]
ee
[%][c]
1
2[d]
91
88
92 (R)
94 (R)
92
87
93 (S)
95 (S)
3
4[d]
93
91
92 (R)
94 (R)
91
93
94 (S)
96 (S)
5
6[d]
92
91
95 (S)
98 (S)
90
92
96 (R)
99 (R)
7
8[d]
94
92
96 (S)
99 (S)
93
91
97 (R)
99 (R)
9[d]
95
94 (S)
92
95 (R)
10
11[d]
93
94
95 (S)
97 (S)
94
91
97 (R)
99 (R)
12
13[d]
91
92
94 (R)
97 (R)
90
93
96 (R)
98 (R)
14
15[d]
93
91
96 (R)
98 (R)
94
93
96 (S)
99 (S)
16
89
92
91
97 (S)
53 (S)
28 (+)
92
95
94
99 (R)
56 (R)
30 (À)
17[e]
18[e]
19[e]
20[e]
92
93
91 (+)
68 (+)
94
91
94 (À)
70 (À)
[a] Reactions were performed at 238C with [PdCl(h3-C3H5)]2 (0.5 mol%), CH2Cl2 as solvent, ligand (1 mol%), BSA (3 equiv.), KOAc (3 mg). [b] Full conversions
were achieved after 12 and 24 h for reactions performed at 23 and 58C, respectively. [c] ee determined by chiral HPLC or GC. [d] Reactions performed at
58C for 24 h. [e] Reactions performed using 2 mol% [PdCl(h3-C3H5)]2, 4 mol% ligand, Cs2CO3 (3 equiv.). Full conversions were achieved in all cases.
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molecules (see below). Excellent enantiocontrol was also ach-
ieved if the b-diketone acetophenone and N-benzylamine were
used as nucleophiles (ee values up to 99%; entries 14–16). No-
tably, the excellent results achieved using benzylamine validate
the use of ammonia as a nucleophile for the computational
model. In all cases, both enantiomers of the substituted prod-
uct can be obtained in high yields and enantioselectivities.
We then went on to study the allylic substitution of S1
using alkyl alcohols as a challenging class of O-nucleophiles.
The stereoselective construction of compounds with ether
groups next to a chiral carbon atom is important for the prep-
aration of biologically active compounds.[22] Although the
enantioselective Pd-catalyzed allylic etherification is currently
studied by several research groups, few successful examples
have been reported. Among them phenols have been the
most studied,[23] whereas aliphatic alcohols have been explored
less.[11f,24] The reaction of Pd/L5e and Pd/L5d with several sub-
stituted benzylic alcohols proceeded smoothly to afford both
enantiomers of the desired products in high yields (Table 4, en-
tries 17–20). Furthermore, the enantioselectivity was influenced
by the electronic nature of the substituted benzylic alcohol.
The highest enantioselectivity (ee values up to 94%; entry 19)
was obtained if the benzylic alcohol contained an electron-de-
ficient para-CF3 substituent, and the selectivity diminished
gradually as the substituent became more electron rich. This
behavior is the opposite to that observed in the etherification
reaction with the Pd/(S,Rp)-FerroNPS ((S)-N-methyl-N-diphenyl-
phosphino-1-[(R)-2-cyclohexylthio)ferrocenyl]ethylamine) cata-
lytic system,[24c] which is one of the few Pd catalysts that has
been designed especially for this purpose and applied success-
fully. The Hammett plot of this electronic effect shows a linear
free-energy relationship between the enantioselectivity and
the electronic character of the substituent (Figure 4; 1=
Figure 5. Pd-catalyzed allylic substitution of S3–S8 using several C-nucleo-
philes. Full conversions were achieved in all cases. [PdCl(h3-C3H5)]2
(0.5 mol%), CH2Cl2 as solvent, ligand (1 mol%), 238C, 18 h. a Reaction per-
formed at 58C for 24 h.
S8) to substrate S1 (Figure 5; 27–36). The results obtained
using S3 followed the same trend as the use of S1. High enan-
tioselectivities in both enantiomers of the substituted product
were obtained in the alkylation of S3 using several malonates,
which include those a-substituted with allyl and butenyl
groups (ee values up to 99%, 27–29). In addition, the catalytic
performance is unaffected by the presence of electron-with-
drawing groups at the para position as well as by the introduc-
tion of meta and ortho substituents at the phenyl groups.
Thus, high enantioselectivities were also achieved for the allylic
alkylation of S4–S6 (Figure 5; ee values up to 94%, 30–32).
The allylic substitution of S7, which is less sterically demanding
and is substituted much less enantioselectively than S1,[26] also
proceeded smoothly (33–35). Although the enantioselectivity
depended on the steric properties of the nucleophile, we were
pleased to see that the enantioselectivities were higher for the
more challenging a-substituted malonates (34–35, ee values
up to 81%) than for the standard dimethyl malonate. Finally,
we were pleased to find that Pd/L5d–e also provided high
enantioselectivity, in both enantiomers of the alkylated prod-
uct, of the more demanding substrate S8 (95% ee), which usu-
ally reacts with lower yields and enantioselectivities than
model substrate S1.
Figure 4. Hammett plot of the Pd-catalyzed allylic etherification of S1 with
L5e.
Finally, the good performance of Pd/L5e was also seen in
the allylic substitution of cyclic substrates using a range of C-
nucleophiles, which included the less studied a-substituted
malonates and b-diketones. For S2, the enantioselectivities
were as high as those obtained with dimethyl malonate
(Table 5; entries 1–5, 37–41). Even more interesting is the high
enantioselectivity achieved using other cyclic substrates with
a different ring size (S9 and S10). The enantiocontrol was high
1.78).[25] This plot could, therefore, be used to predict the enan-
tioselectivity of an asymmetric allylic substitution if para-substi-
tuted benzylic alcohols are used.
The scope of the Pd/L5d and Pd/L5e catalytic systems was
further studied by using other linear substrates [Eq. (2)] that
have different electronic (S3–S5) and steric requirements (S6–
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and ring-closing metathesis reactions (Scheme 2a) or
the sequential allylic substitution and cycloisomeriza-
tion of the 1,6-enyne (Scheme 2b). Thus, allyl-substi-
tuted compounds [17–19, 28–29, and 35; Eq. (2)]
that bear a terminal alkene can undergo clean ring-
closing metathesis with no loss in enantiomeric
excess. A range of five-, six-, and seven-membered
carbocycles with different substituents (R=Me, Ph,
pTol) were prepared in good yields and high enantio-
selectivities (46–51; Scheme 2a). Also, the carbobicy-
cle hydrindane 52 is obtained by cycloisomerization
of the 1,6-enyne 40, which is produced from the AAA
of S2 with dimethyl propargylmalonate, using the
methodology described by Uozumi and coworkers
(Scheme 2b).
Table 5. Allylic substitution of cyclic S2, S6, and S7 with several C-nucleophiles using
the Pd/L5e catalytic system.[a]
Entry
Substrate
Nucleophile
Product
Yield
[%][b]
ee
[%][c]
1
2
3
4
S2
S2
S2
S2
89
91
94
93
83 (S)
86 (+)
90 (À)
87 (S)
NMR spectroscopy of key Pd-h3-allyl intermediates
5
S2
92
76 (À)
Our DFT studies have shown that enantioselectivity is
determined during the nucleophilic attack (see
above). Consequently, the structural elucidation of
the Pd-allyl intermediates and the determination of
their relative reactivity towards the nucleophile are
essential to understand their catalytic behavior. For
this purpose, we studied the Pd-h3-allyl compounds
53–57 ([Pd(h3-allyl)(P-N)]BF4; P-N=L4–L6d–e) to
obtain further insight into how the ligand parameters
affect catalytic performance (Scheme 3). These ionic
Pd complexes, which contain 1,3-diphenyl or cyclo-
hexenyl allyl groups, were prepared using the
method from the corresponding Pd-allyl dimer re-
ported previously and the appropriate ligand in the
presence of silver tetrafluoroborate (Scheme 3).[27]
The complexes were characterized by elemental anal-
6
7
S6
S6
88
92
75 (À)
84 (S)
8
9
S7
S7
93
94
91 (S)
93 (S)
[a] Reactions were performed at 58C with [PdCl(h3-C3H5)]2 (0.5 mol%), CH2Cl2 as sol-
vent, ligand (1 mol%), BSA (3 equiv.), KOAc (3 mg). [b] Full conversions were achieved
after 24 h. [c] ee determined by chiral HPLC or GC.
1
ysis and H, 13C, and 31P NMR spectroscopy. The spec-
1
in both cases, even in the allylic substitution of S9 (42 and 43),
which is usually alkylated much less enantioselectively than
six- and seven-membered cyclic substrates.
tral assignments were based on information from H-1H, 31P-1H,
1
and 13C-1H correlation measurements in combination with H-
1H NOESY experiments. Unfortunately, we were unable to
In summary, by the theoretically guided optimization of the
crucial stereodefining moieties in this new modular amino
phosphite ligand library, we have been able to identify one of
the very few catalytic systems that can create new CÀC, CÀN,
and CÀO bonds with high activities and enantioselectivities in
a number of substrate types, which have different electronic
and steric proprieties, using a wide range of nucleophiles.
Synthetic applications of the allylic substitution compounds:
Preparation of chiral carbocycles
Asymmetric allylic alkylation (AAA) is a relevant method for the
creation of chiral CÀC and CÀheteroatom bonds. Furthermore,
functionalized substrates (e.g., 17–19, 28–29, and 35 formed
by Pd-AAA with nucleophiles that contain allyl, butenyl, and
pentenyl groups) open up new pathways to build more com-
plex molecules easily. To illustrate these aspects, we have pre-
pared a range of chiral carbocycles (46–51) by simple tandem
reactions that involve the allylic substitution of the substrate
Scheme 2. Preparation of chiral carbocycles by the sequential allylic substi-
tution of functionalized olefins/cyclization reactions.
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tween the terminal allyl proton trans to the phosphite moiety,
whereas this interaction appeared with the central allyl proton
in the minor isomer 53 and major isomer of 54 (Figure 6).
Moreover, the other methyl substituent of the amino group
(the one that shows a NOE interaction with the H atom at-
tached to C-1) also shows a NOE interaction with the central
allyl proton in the major isomer 53 and the minor isomer of
54, whereas this interaction appears with the terminal allyl
proton trans to the phosphite moiety for the minor and major
isomers of 54 and 54, respectively. Finally, the minor isomer of
53 and major isomer of 54 showed NOE interactions between
the terminal allyl proton trans to the amino group with one of
the tert-butyl substituents at the biaryl phosphite moiety (the
one that shows NOE contacts with the H atom attached to
C-1). These interactions can be explained by assuming a syn/
syn endo disposition for the major and minor isomers of 53
and 54 and a syn/syn exo disposition for the minor and major
isomers of 53 and 54 (Scheme 4). Although the population of
the Pd-allyl intermediates obtained by DFT calculations is dif-
ferent to that found by NMR spectroscopy, the general trend is
reproduced well. Thus, although for Pd/L4d the major isomer
is Pd-h3-endo, for Pd-L4e the
Scheme 3. Preparation of [Pd(h3-allyl)(P-N)]BF4 (53–57).
obtain crystals of sufficient quality to perform XRD measure-
ments.
Palladium 1,3-diphenyl allyl complexes
The variable-temperature (VT) NMR spectra (30 to À808C) of
Pd-allyl intermediates 53 and 54, which contain ephedrine-
based L4d and L4e, respectively, showed a mixture of two iso-
mers in equilibrium at a ratio of 7:2 and 1:5, respectively.[28]
Both isomers were assigned unambiguously by NMR spectros-
copy to the two syn/syn Pd-h3-endo and exo isomers
(Scheme 4).
major isomer is Pd-h3-exo.
In all isomers, the chemical
shifts in the 13C NMR spectra in-
dicate that the most electrophilic
allyl C terminus is trans to the
phosphite moiety (Scheme 4). If
we assume that the nucleophilic
attack takes place at the more
electrophilic allyl C terminus,[1]
which is in line with the DFT cal-
culations, the stereochemical
outcome of the reaction is not
controlled fully by the popula-
Scheme 4. Diastereoisomer Pd-allyl intermediates for S1 with L4d and L4e. The relative amounts of each isomer
are shown in parentheses. The chemical shifts [ppm] of the allylic terminal carbon atoms are also shown.
tion of the Pd-allyl intermediates
(note that the diastereomeric ex-
cesses differ from the ee values).
In all cases, the NOE indicated interactions between the two
terminal protons of the allyl group, which indicates a syn/syn
disposition (Figure 6). In addition, for the major isomer of 53
and the minor isomer of 54, one of the methyl substituents of
the amino group (the one that shows a NOE interaction with
the H atom attached to C-2) showed a NOE interaction be-
So, the relative electrophilicity of the terminal allylic C atoms
of each isomer plays an important role and has to been taken
into account. In this respect, the Pd/L4d catalyst shows
a higher electronic difference between the more electrophilic
allylic terminal C atoms of both isomers (D(d13C)=6 ppm) than
Pd/L4e (D(d13C)=2 ppm). This higher electronic difference
makes the major isomer of Pd/L4d react faster than the major
isomer of Pd/L4e and accounts fully for the higher enantiose-
lectivity achieved with Pd/L4d than Pd/L4e.
The VT-NMR spectra of Pd-allyl intermediate 55, which con-
tains L5e and differs from the previous Pd/L4d–e catalysts in
that the methyl substituent of the ephedrine ligand backbone
has been removed, also had a mixture of two syn/syn Pd-h3-
endo and exo isomers in a ratio of 1:2 (Scheme 5).
Furthermore, the most electrophilic allyl C terminus was
trans to the phosphite moiety. However, an important differ-
ence between 53 and 54 is the higher electronic differentiation
between the more electrophilic allylic terminal C atoms of
both isomers in 55 (D(d13C)=11 ppm) than in 53 and 54
Figure 6. Relevant NOE contacts from the NOESY experiment of [Pd(h3-1,3-
diphenylallyl)(L4d)]BF4 (53) isomers are shown as an example. The same
NOE contacts were observed for the isomers of [Pd(h3-1,3-diphenylallyl)-
(L4e)]BF4 (54).
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1,3-cyclohexenyl-allyl intermediate 56, which contains ephe-
drine-based amino phosphite ligand L4e, and compared it
with its related amino phosphite counterpart Pd/L5e. The VT-
NMR spectra (35 to À808C) of Pd intermediates 56 and 57
showed a mixture of the two possible isomers at a ratio of
10:1 and 20:1, respectively (Scheme 6). The major isomers
were assigned unambiguously by NOE to Pd-h3-endo isomers
(Figure 8). In both cases, the NOE indicates interactions be-
tween the central allyl proton and one of the methyl substitu-
ents of the amino group (the one that shows a NOE interaction
with the H atom attached to C-1 of the ligand backbone) and
with one of the tert-butyl substituents at the biaryl phosphite
moiety (the one that also shows a NOE contact with the H
atom attached to C-1; Figure 8). The chemical shifts of the
Scheme 5. Diastereoisomer Pd-allyl intermediates for S1 with L5e. The rela-
tive amounts of each isomer are shown in parentheses. The chemical shifts
[ppm] of the allylic terminal carbon atoms are also shown.
(D(d13C)=6 and 2 ppm, respec-
tively). This higher electronic dif-
ferentiation may explain the
higher enantioselectivity ob-
tained with Pd/L5e than that
with Pd/L4d–e. Accordingly, the
reactivity of the Pd intermedi-
ates with sodium malonate at
low temperature studied by
in situ NMR spectroscopy indi-
cates that the major Pd-h3-exo
isomer reacts four times faster
than the minor Pd-h3-endo
isomer (Figure 7), which agrees
Scheme 6. Diastereoisomer Pd-allyl intermediates for S2 with L4e and L5e. The relative amounts of each isomer
fully with the ee obtained experi-
are shown in parentheses. The chemical shifts [ppm] of the allylic terminal carbons are also shown.
mentally.
Figure 8. Relevant NOE contacts from the NOESY experiments for the major
isomers of [Pd(h3-1,3-cyclohexenylallyl)(L)]BF4 (56 and 57; L=L4e and L5e,
respectively).
13C NMR spectra indicated that the most electrophilic allylic C
terminus is trans to the phosphite moiety. If we assume that
Figure 7. 31P-{1H} NMR spectra of [Pd(h3-1,3-diphenylallyl)(L5e)]BF4 (55) in
CD2Cl2 at À808C a) before the addition of sodium malonate and b) after the
addition of sodium malonate.
the nucleophilic attack takes place at the most electrophilic
allyl C terminus and if we take into account the observed ste-
reochemical outcome of the reaction (70% S for 56 and 82% S
for 57) and that the ee values of the alkylation product 13 are
different from the diastereoisomeric excesses (de) of the Pd in-
termediates (de=81% S for 56 and 90% S for 57), the minor
isomers must react slightly faster than the major isomers. This
is in agreement with the slightly higher electrophilicity of the
allylic terminal C atom trans to the phosphite moiety located
Palladium 1,3-cyclohexenyl allyl complexes
Finally, in an attempt to provide further information about the
positive effect on the enantioselectivity observed in the allylic
substitution of unhindered cyclic S2 if the methyl substituent
of the ephedrine backbone was removed, we studied the Pd-
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pared following the methodology described by Uozumi et al.[33] 1H,
13C{1H}, and 31P{1H} NMR spectra were recorded by using a 400 MHz
spectrometer. Chemical shifts are relative to that of SiMe4 (1H and
13C) as the internal standard or H3PO4 (31P) as the external standard.
at the minor isomers (i.e., D(d13C) around 1 ppm for Pd/L4e).
The lower enantioselectivities obtained with Pd/ephedrine-
based amino phosphite L4e than with the related Pd/L5e cat-
alytic system can, therefore, be attributed to the increase in
the relative amount of the fast-reacting exo isomer with re-
spect to the endo isomer compared with the population of the
endo and exo isomers in Pd/L5e.
1
1
1H, 13C, and 31P assignments were made based on H-1H gCOSY, H-
1
13C gHSQC and H-31P gHMBC experiments.
Preparation of (1S,2R)-2-[tert-butyl(methyl)amino]-1-phenyl-
propan-1-ol (10)
Conclusions
Compound 9 (1 g, 4.88 mmol) was dissolved in dry ether (20 mL).
The solution was stirred in an ice-bath for 5 min, and MeMgBr (3m
in diethyl ether, 4.96 mL, 14.64 mmol) was added dropwise. The so-
lution was warmed to reflux, and the reaction was kept at that
temperature for 8 h. The reaction was quenched with saturated
NH4Cl (20 mL), and the aqueous layer was extracted with CH2Cl2
(3”20 mL). The combined organic layers were dried over MgSO4,
A new library of modular amino phosphite ligands has been
tested successfully in the asymmetric Pd-catalyzed allylic sub-
stitution of substrates with different steric and electronic re-
quirements with a large variety of nucleophiles. These ligands,
which are prepared in a few steps from readily available enan-
tiopure amino alcohols, include the benefits of a high stability
of the amine moiety and the additional control provided by
both the adaptability of the chiral cavity caused by the biaryl
phosphite groups and the flexibility of the chiral pocket
through a highly modular ligand scaffold. Other advantages of
these ligands are that they are solid, stable to air and other ox-
idizing agents and are, therefore, easy to handle and can be
manipulated and stored in air. In two or three simple steps,
several ligand parameters have been tuned to maximize the
catalyst performance. Enantioselectivity is controlled mainly by
the substituents/configuration at the biaryl phosphite moiety
and by the amine substituents, whereas the configuration of
the ephedrine backbone has less effect. Theoretically guided
optimization based on DFT studies allowed us to rationalize
the modifications required in the ligand to improve selectivity.
These results led to the identification of one of the very few
catalytic systems that can create CÀC, CÀN, and CÀO bonds in
substrates with a variety of electronic and steric proprieties in
high yields and enantioselectivities (ee values up to 99%)
using a wide range of nucleophiles. Further studies on the Pd-
p-allyl intermediates provided a deep understanding of the
effect of the ligand parameters on the origin of the enantiose-
lectivity. Potential applications of the new Pd/amino phosphite
catalysts were demonstrated by the synthesis of a range of
chiral five-, six-, and seven-membered carbocycles by simple
tandem reactions with no loss of enantioselectivity. These re-
sults open up the asymmetric Pd-catalyzed allylic substitution
of several substrate types with a wide range of nucleophiles to
the potential effective use of readily available and highly mod-
ular amino phosphite ligands.
and the removal of solvents provided 10 as a pale-yellow solid.
3
Yield: 1.0 g (93%); 1H NMR (CDCl3): d=0.94 (d, 3H, CH3, JHÀH
=
7.2 Hz), 1.06 (s, 9H, tBu), 2.0 (s, 3H, CH3ÀN), 3.35 (m, 1H, CHÀN),
4.50 (m, 1H, CHÀO), 7.21–7.32 ppm (m, 4H, CH=); 13C NMR (CDCl3):
d=12.9 (CH3), 27.1 (CH3, tBu), 30.9 (CH3, NMe), 55.1 (C, tBu), 55.2
(CHÀN), 75.3 (CHÀO), 126.7 (CH=), 126.8 (CH=), 127.5 (CH=),
143.1 ppm (C).
Preparation of (1S,2R)-2-[methyl(2-phenylpropan-2-yl)ami-
no]-1-phenylpropan-1-ol (11)
Compound 9 (1 g, 4.88 mmol) was dissolved in dry THF (20 mL).
The solution was stirred in an ice-bath for 5 min, and PhMgBr (1m
in THF, 14.7 mL, 14.64 mmol) was added dropwise. Then, the reac-
tion was warmed to reflux and kept at that temperature for 8 h.
The reaction was quenched with saturated NH4Cl (20 mL), and the
aqueous layer was extracted with CH2Cl2 (3”20 mL). The combined
organic layers were dried over MgSO4. The organic solvents were
removed, and the crude was purified by silica flash chromatogra-
phy (AcOEt/light petroleum/NEt3 6:2:0.1) to afford 11 as a white
solid. Yield: 1.2 g (87%); 1H NMR (CDCl3): d=0.95 (d, 3H, CH3,
3JHÀH =7.1 Hz), 1.34 (s, 3H, CH3), 1.43 (s, 3H, CH3), 2.13 (s, 3H, CH3À
N), 3.20 (m, 1H, CHÀN), 4.50 (d, 1H, CHÀO, 3JHÀH =4.8 Hz), 7.10–
7.38 ppm (m, 10H, CH=); 13C NMR (CDCl3): d=11.7 (CH3), 24.8
(CH3), 25.6 (CH3), 30.9 (CH3, NMe), 56.4 (C, CMe2Ph), 61.0 (CHÀN),
77.6 (CHÀO), 126.2 (CH=), 126.3 (CH=), 126.4 (CH=), 126.8 (CH=),
127.7 (CH=), 127.9 (CH=), 143.3 (C), 149.0 ppm (C).
General procedure for the preparation of amino phosphite
ligands L1–L6a–g
Phosphorochloridite (1.1 mmol) produced in situ was dissolved in
toluene (5 mL), and pyridine (0.18 mL, 2.3 mmol) was added.
Amino alcohol (1 mmol) was dried azeotropically with toluene (3”
1 mL) and then dissolved in toluene (5 mL), to which pyridine
(0.18 mL, 2.3 mmol) was added. The phosphorochloridite solution
was transferred slowly to the solution of amino alcohol. The reac-
tion mixture was stirred at RT for 90 h (L1, L4–L6a–g) or 15 h (li-
gands L2, L3a–g), and the pyridine salts were removed by filtra-
tion. Evaporation of the solvent gave a white foam, which was pu-
rified by flash chromatography in alumina (toluene/NEt3 100:1) to
produce the corresponding ligand as a white solid.
Experimental Section
General considerations
All reactions were performed using standard Schlenk techniques
under an Ar atmosphere. Solvents were purified and dried by stan-
dard procedures. Phosphorochloridites were prepared in one step
from the corresponding biaryls.[29] Enantiopure amino alcohols 5–
8[12] and oxazolidine 9[13] were prepared as described previously.
Racemic substrates S1–S10 were prepared as reported previous-
L1a: Yield: 303 mg (49%); 31P NMR (C6D6): d=150.5 ppm (s);
[32]
3
ly.[30] [Pd(h3--1,3-Ph2-C3H3)(m-Cl)][31] and [Pd(h3-cyclohexenyl)(m-Cl)]2
1H NMR (C6D6): d=0.98 (d, 3H, CH3, JHÀH =6.8 Hz), 1.29 (s, 9H, CH3,
were prepared as described previously. Carbocycle 49 was pre-
tBu), 1.3 (s, 9H, CH3, tBu), 1.48 (s, 9H, CH3, tBu), 1.62 (s, 9H, CH3,
ChemCatChem 2015, 7, 4091 – 4107
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Full Papers
tBu), 2.14 (s, 6H, CH3, NMe2), 2.59 (m, 1H, CHÀN), 5.55 (dd, 1H,
(ESI+): m/z: calcd for C37H44NO3PSi2: 638.2673 [M+H]+; found
638.2670.
3
3
CHÀO, JHÀP =8 Hz, JHÀH =4 Hz,), 7.03–7.25 (m, 7H, CH=), 7.33 (d,
4
4
1H, CH=, JHÀH =2.4 Hz), 7.37 (d, 1H, CH=, JHÀH =2.4 Hz), 7.58 (d,
1H, CH=, 4JHÀH =2.0 Hz), 7.61 ppm (d, 1H, CH=, 4JHÀH =2.8 Hz);
13C NMR (C6D6): d=8.4 (CH3), 28.8 (CH3,tBu), 28.9 (CH3, tBu), 29.9
(CH3,tBu), 30.2 (CH3,tBu), 33.2 (C, tBu), 34.1 (C, tBu), 34.3 (C, tBu),
40.9 (CH3, NMe), 41.0 (CH3, NMe), 64.7 (d, CHÀN, 3JCÀP =9.2 Hz),
L1g: Yield: 400 mg (63%); 31P NMR (C6D6): d=148.5 ppm (s);
1H NMR (C6D6): d=0.51 (s, 9H, CH3, SiMe3), 0.52 (s, 9H, CH3, SiMe3),
1.09 (d, 3H, CH3, 3JHÀH =6.4 Hz), 2.05 (s, 6H, CH3, NMe2), 2.87 (m,
3
3
1H, CHÀN), 5.35 (dd, 1H, CHÀO, JHÀP =8.4 Hz, JHÀH =6.5 Hz), 6.7–
2
7.3 (m, 6H, CH=), 7.68 (m, 2H, CH=), 7.95 (s, 1H; CH=), 8.05 ppm (s,
76.6 (d, CHÀO, JCÀP =9.2 Hz), 122.6–145.4 ppm (aromatic C); TOF-
1H, CH=); 13C NMR (C6D6): d=À0.2 (d, CH3, SiMe3, JCÀP =4.6 Hz),
MS (ESI+): m/z: calcd for C39H56NO3P: 618.4101 [M+H]+; found
3
À0.1 (CH3, SiMe3), 9.2 (CH3), 41.3 (CH3, NMe2), 64.3 (d, CHÀN, JCÀP
=
618.4071.
4.6 Hz), 78.9 (d, CHÀO, 2JCÀP =2.3 Hz), 122.4–152.3 ppm (aromatic
C); TOF-MS (ESI+): m/z: calcd for C37H44NO3PSi2: 638.2669 [M+H]+;
found 638.2670.
L1b: Yield: 170 mg (30%); 31P NMR (C6D6): d=150.2 ppm (s);
3
1H NMR (C6D6): d=1.00 (d, 3H, CH3, JHÀH =6.4 Hz), 1.38 (s, 9H, CH3,
tBu), 1.56 (s, 9H, CH3, tBu), 2.14 (s, 6H, CH3, NMe2), 2.57 (m, 1H,
L2a: Yield: 330 mg (50%); 31P NMR (C6D6): d=148.4 ppm (s);
1H NMR (C6D6): d=0.83 (s, 9H, CH3, tBu, NtBu), 1.21 (d, 3H, CH3,
3JHÀH =6.4 Hz), 1.31 (s, 9H, CH3, tBu), 1.33 (s, 9H,CH3, tBu), 1.56 (s,
9H, CH3, tBu), 1.61 (s, 9H, CH3, tBu), 2.11 (s, 3H, NMe), 3.4 (m, 1H,
CHÀN), 5.25 (m, 1H, CHÀO), 7.0–7.2 (m, 6H, CH=), 7.37 (m, 2H,
CHÀN), 3.33 (s, 3H, CH3, OMe), 3.34 (s, 3H, CH3, OMe), 5.5 (dd, 1H,
4
CHÀO, 3JHÀP =8.0 Hz, 3JHÀH =4.0 Hz), 6.67 (d, 1H, CH=, JHÀH
=
2.8 Hz), 6.72 (d, 1H, CH=, 4JHÀH =3.2 Hz), 7.01–7.26 ppm (m, 7H,
CH=); 13C NMR (C6D6): d=9.5 (CH3), 30.6 (CH3,tBu), 30.7 (CH3, tBu),
35.1(C, tBu), 35.2 (C, tBu), 41.9 (CH3, NMe), 42.1 (CH3, NMe), 54.7
4
CH=), 7.60 ppm (d, 1H, CH=, JHÀH =2 Hz); 13C NMR (C6D6): d=12.8
2
(CH3, OMe), 65.8 (CHÀN), 77.6 (d, CHÀO, JCÀP =9.9 Hz), 112.6–155.9
(CH3), 26.8 (CH3, tBu), 29.3 (NMe), 31.0 (CH3, tBu), 31.1 (CH3, tBu),
(aromatic C); TOF-MS (ESI+): m/z: calcd for C33H44NO5P: 566.3028
[M+H]+; found 566.3030.
31.2 (CH3, tBu), 31.3 (CH3, tBu), 34.3 (C, tBu), 35.2 (C, tBu), 35.3 (C,
3
tBu), 54.1 (C, tBu, NtBu), 56.6 (d, CHÀN, JCÀP =3.1 Hz), 81.3 (d, CHÀ
L1c: Yield: 194 mg (32%); 31P NMR (C6D6): d=152.4 ppm (s);
1H NMR (C6D6): d=0.33 (s, 9H, CH3ÀSi), 0.44 (s, 9H, CH3ÀSi), 0.95 (d,
O, 2JCÀP =5.43 Hz), 123.8–146.7 ppm (aromatic C); TOF-MS (ESI+):
m/z: calcd for C42H62NO3P: 660.5438 [M+H]+; found 660.4540.
3
3H, CH3, JHÀH =6.8 Hz), 2.10 (s, 6H, CH3, NMe2), 2.68 (m, 1H, CHÀ
L2d: Yield: 422.6 mg (70%); 31P NMR (C6D6): d=141.1 ppm (s);
1H NMR (C6D6): d=0.84 (s, 9H, CH3, tBu, NtBu), 2.15 (d, 3H, CH3,
3JHÀH =6.4 Hz), 1.51 (s, 9H, CH3, tBu), 1.63 (s, 9H,CH3, tBu), 1.69 (s,
3H, CH3), 1.71 (s, 3H, CH3,), 2.04 (s, 3H, CH3), 2.11 (s, 3H, CH3), 2.16
(s, 3H, NMe), 3.4 (m, 1H, CHÀN), 5.1 (m, 1H, CHÀO), 7.0–7.3 ppm
(m, 7H, CH=); 13C NMR (C6D6): d=12.7 (CH3), 16.1 (CH3), 16.3 (CH3),
20.0 (CH3), 20.1 (CH3), 26.8 (CH3, tBu), 29.4 (NMe), 31.1 (d, CH3, tBu,
N), 5.45 (dd, 1H, CHÀO, 3JHÀP =8.8 Hz, 3JHÀH =5.6 Hz), 7.03–
7.46 ppm (m, 11 H, CH=); 13C NMR (C6D6): d=0.0 (CH3ÀSi), 0.1 (CH3À
3
Si), 9.7 (CH3), 42.1 (CH3, NMe2), 65.8 (d, CHÀN, JCÀP =2.3 Hz), 78.1
(d, CHÀO, 2JCÀP =4.8 Hz), 124.7–155.2 ppm (aromatic C); TOF-MS
(ESI+): m/z: calcd for C29H40NO3PSi2: 538.2354 [M+H]+; found
538.2357.
L1d: Yield: 188 mg (32%); 31P NMR (C6D6): d=141.1 ppm (s);
J
CÀP =5.3 Hz), 31.4 (CH3, tBu), 34.4(C, tBu), 34.7 (C, tBu), 54.2 (C, tBu,
3
1H NMR (C6D6): d=1.12 (d, 3H, CH3, JHÀH =7.2 Hz), 1.46 (s, 9H, CH3,
3
2
NtBu), 56.4 (d, CHÀN, JCÀP =5.6 Hz), 81.6 (d, CHÀO, JCÀP =3.0 Hz),
125.3–145.6 ppm (aromatic C); TOF-MS (ESI+): m/z: calcd for
C39H56NO3P: 604.3917 [M+H]+; found 604.3914.
tBu), 1.63 (s, 9H, CH3, tBu), 1.69 (s, 3H, CH3), 2.05 (s, 3H, CH3), 2.14
(s, 3H, CH3), 2.15 (s, 3H, CH3), 2.16 (s, 6H, CH3, NMe2), 2.82 (m, 1H,
CHÀN), 5.4 (dd, 1H, CHÀO, 3JHÀP =8.0 Hz, 3JHÀH =5.6 Hz), 7.0–
7.3 ppm (m, 7H, CH=); 13C NMR (C6D6): d=8.1 (CH3), 15.1 (CH3),
15.3 (CH3), 19.0 (CH3), 19.1 (CH3), 29.9 (d, CH3, tBu, JCÀP =5.4 Hz),
L2e: Yield: 392 mg (65%); 31P NMR (C6D6): d=142.9 ppm (s);
1H NMR (C6D6): d=0.60 (s, 9H, CH3, tBu, NtBu), 1.0 (d, 3H, CH3,
3JHÀH =6.8 Hz), 1.51 (s, 9H, CH3, tBu), 1.60 (s, 9H,CH3, tBu), 1.66 (s,
3H, CH3), 1.75 (s, 3H, CH3,), 1.95 (s, 3H, NMe), 2.0 (s, 3H, CH3), 2.1
(s, 3H, CH3), 3.2 (m, 1H, CHÀN), 5.0 (m, 1H, CHÀO), 7.0–7.45 ppm
(m, 7H, CH=); 13C NMR (C6D6): d=13.8 (CH3), 16.2 (CH3), 16.4 (CH3),
20.0 (CH3), 20.1 (CH3), 26.8 (CH3, tBu), 28.7 (NMe), 31.2 (d, CH3, tBu,
30.4 (CH3, tBu), 33.2 (C, tBu), 33.7 (C, tBu), 40.5 (CH3, NMe), 40.6
2
(CH3, NMe), 63.9 (d, CHÀN, 3JCÀP =6.1 Hz), 77.3 (d, CHÀO, JCÀP
=
6.2 Hz), 124.3–144.6 ppm (aromatic C); TOF-MS (ESI+): m/z: calcd
for C35H48NO3P: 562.3452 [M+H]+; found 562.3445.
L1e: Yield: 182 mg (31%); 31P NMR (C6D6): d=144.9 (s); 1H NMR
(C6D6): d=0.78 (d, CH3, 3H, 3JHÀH =6.4 Hz), 1.41 (s, 9H, CH3, tBu),
1.59 (s, 9H, CH3, tBu), 1.66 (s, 3H, CH3), 1.72 (s, 3H, CH3), 2.03 (s,
3H, CH3), 2.05 (s, 3H, CH3), 2.11 (s, 6H, CH3, NMe2), 2.37 (m, 1H,
CHÀN), 5.41 (dd, 1H, CHÀO, 3JHÀP =8.0 Hz, 3JHÀH =4.0 Hz), 6.95–
7.22 ppm (m, 7H, CH=); 13C NMR (C6D6): d=9.7 (CH3), 16.2 (CH3),
16.4 (CH3), 20.0 (CH3), 20.1(CH3), 30.9 (d, CH3, tBu, JCÀP =4.6 Hz),
31.2 (CH3, tBu), 34.5 (C, tBu), 34.7 (C, tBu), 42.0 (CH3, NMe), 42.3
(CH3, NMe), 62.2 (CHÀN), 77.2 (d, CHÀO, 2JCÀP =10.7 Hz), 125.3–
146.2 ppm (aromatic C); TOF-MS (ESI+): m/z: calcd for C35H48NO3P:
562.3448 [M+H]+; found 562.3445.
J
CÀP =5.4 Hz), 31.6 (CH3, tBu), 34.5 (C, tBu), 34.8 (C, tBu), 53.7 (C,
2
tBu, NtBu), 56.7 (d, CHÀN, 3JCÀP =2.3 Hz), 80.3 (d, CHÀO, JCÀP
=
5.3 Hz), 125.9–145.6 ppm (aromatic C); TOF-MS (ESI+): m/z: calcd
for C39H56NO3P: 604.3912 [M+H]+; found 604.3914.
L3a: Yield: 262 mg (37%); 31P NMR (C6D6): d=148.90 ppm (s);
1H NMR (C6D6): d=1.01 (d, 3H, CH3, 3JHÀH =6.8 Hz), 1.09 (s, 3H,
CH3), 1.23 (s, 3H, CH3), 1.28 (s, 9H, CH3, tBu), 1.39 (s, 9H, CH3, tBu),
1.55 (s, 9H, CH3, tBu), 1.86 (s, 9H, CH3, tBu), 2.2 (s, 3H, NMe), 3.2
(m, 1H, CHÀN), 5.4 (dd, 1H, CHÀO, 3JHÀP =9.6 Hz, 3JHÀH =4.4 Hz),
4
7.0–7.4 (m, 12H, CH=), 7.58 (d, 1H, CH=, JHÀH =2.8 Hz), 7.62 ppm
(d, 1H, CH=, 4JHÀH =2.8 Hz); 13C NMR (C6D6): d=9.9 (CH3), 22.3
(CH3), 25.2 (CH3), 28.9 (NMe), 29.9 (CH3, tBu), 30.0 (CH3, tBu), 30.1
(CH3, tBu), 30.2 (CH3, tBu), 33.2 (C, tBu), 34.2(C, tBu), 34.3 (C, tBu),
56.4 (d, CHÀN, 3JCÀP =3.8 Hz), 59.8 (C, N-CMe2Ph), 81.2 (d, CHÀO,
2JCÀP =6.9 Hz), 122.7–148.7 ppm (aromatic C); TOF-MS (ESI+): m/z:
calcd for C47H64NO3P: 722.4694 [M+H]+; found 722.4697.
L1 f: Yield: 439 mg (69%); 31P NMR (C6D6): d=155.8 (s); 1H NMR
(C6D6): d=0.40 (s, 9H, CH3, SiMe3), 0.51 (s, 9H, CH3, SiMe3), 0.72 (d,
3
CH3, 3H, JHÀH =6.8 Hz), 1.96 (s, 6H, CH3, NMe2), 2.50 (m, 1H, CHÀ
3
3
N), 5.43 (dd, 1H, CHÀO, JHÀP =8.4 Hz, JHÀH =4.8 Hz), 6.82–7.4 (m,
3
3
5H, CH=), 7.4 (d, 1H, CH=, JHÀH =8.4 Hz), 7.70 (d, 1H, CH=, JHÀH
=
3
8.0 Hz), 7.8 (d, 1H, CH=, JHÀH =8.4 Hz), 8.1 (s, 1H, CH=), 7.9 ppm (s,
1H, CH=); 13C NMR (C6D6): d=À0.4 (d, CH3, SiMe3, JCÀP =4.6 Hz),
À0.1 (CH3, SiMe3), 9.3 (CH3), 41.8 (CH3, NMe2), 66.0 (CHÀN), 77.5 (d,
CHÀO, 2JCÀP =5.3 Hz), 122.8–152.6 ppm (aromatic C); TOF-MS
L3d: Yield: 244 mg (37%); 31P NMR (C6D6): d=143.4 ppm (s);
1H NMR (C6D6): d=1.01 (d, 3H, CH3, 3JHÀH =6.9 Hz), 1.03, (s, 3H,
CH3), 1.15 (s, 3H, CH3), 1.59 (s, 9H, CH3, tBu), 1.65 (s, 9H, CH3, tBu),
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ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Papers
1.71 (s, 3H, CH3), 1.8 (s, 3H, CH3), 1.91 (s, 3H, NMe), 2.06 (s, 3H,
CH3), 2.14 (s, 3H, CH3), 3.3 (m, 1H, CHÀN), 5.3 (m, 1H, CHÀO), 7.0–
7.3 ppm (m, 12H, CH=); 13C NMR (C6D6): d=10.9 (CH3), 15.2 (CH3),
15.4 (CH3), 19.0 (CH3) 23.4 (CH3), 24.7 (CH3), 28.2 (NMe), 30.2 (d,
CH3, tBu, JCÀP =5.3 Hz), 30.5 (CH3, tBu), 33.4 (C, tBu), 33.7 (C, tBu),
56.3 (d, CHÀN, 3JCÀP =2.3 Hz), 59.4 (C, N-CMe2Ph), 80.7 (d, CHÀO,
2JCÀP =6.1 Hz), 124.3–148.8 ppm (aromatic C); TOF-MS (ESI+): m/z:
calcd for C43H56NO3P: 666.4068 [M+H]+; found 666.4071.
L4g: Yield: 666 mg (95%); 31P NMR (C6D6): d=151 ppm. (s);
1H NMR (C6D6): d=0.4 (s, 9H, CH3, SiMe3), 0.47 (s, 9H, CH3, SiMe3),
0.55 (d, 3H, CH3, 3JHÀH =6.8 Hz), 1.85 (s, 6H, CH3, NMe2), 2.57 (m,
1H, CHÀN), 5.2 (m, 1H, CHÀO), 6.79–7.16 (m, 9H, CH=), 7.19 (d, 1H,
4
4
CH=, JHÀH =8 Hz), 7.32 (d, 1H, CH=, JHÀH =8 Hz), 7.66 (d, 1H, CH=,
4JHÀH =8.8 Hz), 7.73 (d, 1H, CH=, 4JHÀH =8.4 Hz), 8.0 ppm (s, 2H,
CH=); 13C NMR (C6D6): d=À0.3 (d, 9H, CH3, SiMe3, JCÀP =4.6 Hz),
À0.1 (SiMe3), 9.1 (CH3), 41.2 (CH3, NMe2), 64.2 (CHÀN), 78.4 (d, CHÀ
O, 2JCÀP =2.3 Hz), 122.6–152.9 ppm (aromatic C); TOF-MS (ESI+):
m/z: calcd for C37H44NO3PSi2: 638.2669 [M+H]+; found 638.2670.
L3e: Yield: 331.0 mg (50%); 31P NMR (C6D6): d=148.90 ppm (s);
1H NMR (C6D6): d=1.02 (d, 3H, CH3, 3JHÀH =6.8 Hz), 1.03 (s, 3H,
CH3), 1.16 (s, 3H, CH3), 1.59 (s, 9H, CH3, tBu), 1.65 (s, 9H, CH3, tBu),
1.71 (s, 3H, CH3), 1.79 (s, 3H, CH3), 2.01 (s, 3H, CH3, NMe), 2.06 (s,
3H, CH3), 2.15 (s, 3H, CH3), 3.31 (m, 1H, CHÀN), 5.3 (m, 1H, CHÀO),
7.0–7.4 ppm (m, 12H, CH=); 13C NMR (C6D6): d=11.9 (CH3), 16.2
(CH3), 16.5 (CH3), 20.1 (CH3) 24.6 (CH3), 25.7 (CH3), 29.2 (NMe), 31.2
(d, CH3, tBu, JCÀP =5.3 Hz), 31.5 (CH3, tBu), 34.5 (C, tBu), 34.8(C, tBu),
57.3 (CHÀN), 60.5 (C, N-CMe2Ph), 81.7 (d, CHÀO, 2JCÀP =6.1 Hz),
125.3–149.9 ppm (aromatic C); TOF-MS (ESI+): m/z: calcd for
C43H56NO3P: 666.4072 [M+H]+; found 666.4071.
L5d: Yield: 362 mg (64%); 31P NMR (C6D6): d=143.7 ppm (s);
1H NMR (C6D6): d=1.51 (s, 9H, CH3, tBu), 1.76 (s, 9H, CH3, tBu), 1.82
(s, 3H, CH3), 1.89 (s, 3H, CH3), 2.17 (s, 6H, CH3, NMe2), 2.23 (s, 3H,
CH3), 2.24 (s, 3H, CH3), 2.30 (dd, 1H, CH2, 2JHÀH =12.4 Hz,3JHÀH
=
5.6 Hz), 2.73 (dd, 1H, CH2, JHÀH =12.4 Hz,3JHÀH =6 Hz), 5.33 (m, 1H,
CHÀO), 7.13–7.4 ppm (m, 7H, CH=); 13C NMR (C6D6): d=16.1 (CH3),
16.4 (CH3), 20.0 (CH3), 20.1 (CH3), 30.9 (d, CH3,tBu, JCÀP =4.6 Hz),
31.3 (CH3, tBu), 34.5 (C, tBu), 34.6 (C, tBu), 45.5 (CH3, NMe), 45.6
(CH3, NMe), 67.6 (CH2ÀN), 75.2 (d, CHÀO, 2JCÀP =13.6 Hz), 125.3–
146.3 ppm (aromatic C); TOF-MS (ESI+): m/z: calcd for C34H46NO3P:
548.3287 [M+H]+; found 548.3288.
2
L4a: Yield: 276 mg (43%); 31P NMR (C6D6): d=148.4 ppm (s);
3
1H NMR (C6D6): d=0.47 (d, 3H, CH3, JHÀH =6.8 Hz), 1.24 (s, 9H, CH3,
tBu), 1.25 (s, 9H, CH3, tBu), 1.35 (s, 9H, CH3, tBu), 1.62 (s, 9H, CH3,
L5e: Yield: 362 mg (64%); 31P NMR (C6D6): d=138.1 ppm (s);
1H NMR (C6D6): d=1.44 (s, 9H, CH3, tBu), 1.46 (s, 9H, CH3, tBu), 1.65
(s, 3H, CH3), 1.72 (s, 3H, CH3), 1.98 (s, 6H, CH3, NMe2), 2.07 (s, 3H,
tBu), 2.09 (s, 6H, CH3, NMe2), 2.78 (m, 1H, CHÀN), 5.06 (dd, 1H,
3
3
CHÀO, JHÀP =8 Hz, JHÀH =4 Hz), 6.9–7.1 (m, 7H, CH=), 7.27 (d, 1H,
4
4
CH=, JHÀH =2.4 Hz), 7.33 (d, 1H, CH=, JHÀH =2.8 Hz), 7.46 (d, 1H,
CH3), 2.1(s, 3H, CH3), 2.43 (dd, 1H, CH2, 2JHÀH =12.4 Hz,3JHÀH
=
4
4
CH=, JHÀH =2.4 Hz), 7.57 ppm (d, 1H, CH=, JHÀH =2.4 Hz); 13C NMR
2
3
5.6 Hz), 2.85 (dd, 1H, CH2, JHÀH =12.4 Hz, JHÀH =6 Hz), 5.1 (m, 1H,
(C6D6): d=7.9 (CH3), 30.9 (CH3,tBu), 31.1 (CH3, tBu), 31.2 (CH3, tBu),
CHÀO), 6.95–7.19 ppm (m, 7H, CH=); 13C NMR (C6D6): d=16.1
31.3 (CH3, tBu), 33.2 (C, tBu), 34.3 (C, tBu), 40.9 (CH3, NMe), 41.0
2
(CH3, NMe), 64.7 (d, CHÀN, 3JCÀP =1.5 Hz), 76.6 (d, CHÀO, JCÀP
=
(CH3), 16.3 (CH3), 20.0 (CH3), 20.1 (CH3), 30.9 (d, CH3, tBu, JCÀP
=
5.3 Hz), 31.3 (CH3, tBu), 34.3 (C, tBu), 34.6 (C, tBu), 45.6 (CH3, NMe2),
9.2 Hz), 123.6–145.8 ppm (aromatic C); TOF-MS (ESI+): m/z: calcd
for C39H56NO3P: 618.4070 [M+H]+; found 618.4071.
2
2
66.7 (d, CH2ÀN, JCÀP =3.8 Hz), 75.2 (d, CHÀO, JCÀP =8.4 Hz), 125.3–
145.8 ppm (aromatic C); TOF-MS (ESI+): m/z: calcd for C34H46NO3P:
548.3287 [M+H]+; found 548.3288.
L4d: Yield: 344 mg (61%); 31P NMR (C6D6): d=139.0 ppm (s);
3
1H NMR (C6D6): d=0.62 (d, 3H, CH3, JHÀH =7.2 Hz), 1.48 (s, 9H, CH3,
L6d: Yield: 362 mg (64%); 31P NMR (C6D6): d=129.7 ppm (s);
1H NMR (C6D6): d=1.48 (s, 9H, CH3, tBu), 1.53 (s, 9H, CH3, tBu), 1.64
(s, 3H, CH3), 1.72 (s, 3H, CH3), 2.02 (s, 3H, CH3), 2.02 (s, 3H, CH3),
2.04 (s, 6H, CH3, NMe2), 3.4 (m, 1H, CHÀN), 3.6 (m, 1H, CH2ÀO), 4.3
(m, 1H, CH2ÀO), 6.95–7.2 ppm (m, 7H, CH=); 13C NMR (C6D6): d=
16.1 (CH3), 16.3 (CH3), 20.0 (CH3), 20.1 (CH3), 30.9 (CH3, tBu), 31.2 (d,
CH3,tBu, JCÀP =5.3 Hz), 34.4 (C, tBu), 34.5 (C, tBu), 42.9 (CH3, NMe2),
tBu), 1.6 (s, 9H, CH3, tBu), 1.66 (s, 3H, CH3), 1.67 (s, 3H, CH3), 2.04
(s, 3H, CH3), 2.1 (s, 3H, CH3), 2.15 (s, 6H, CH3, NMe2), 3.0 (m, 1H,
CHÀN), 5.1 (dd, 1H, CHÀO, 3JHÀH =5.6 Hz, 3JHÀP =8.0 Hz), 6.9–
7.2 ppm (m, 7H, CH=); 13C NMR (C6D6): d=7.4 (CH3), 15.1 (CH3),
15.3 (CH3), 19.0 (CH3), 30.0 (d, CH3, tBu, JCÀP =5.4 Hz), 30.4 (CH3,
tBu), 33.3 (C, tBu), 33.7 (C, tBu), 40.1 (CH3, NMe), 40.2 (CH3, NMe),
3
2
63.9 (d, CHÀN, JCÀP =3.8 Hz), 77.6 (d, CHÀO, JCÀP =10.7 Hz), 126.3–
144.6 ppm (aromatic C); TOF-MS (ESI+): m/z: calcd for C35H48NO3P:
562.3440 [M+H]+; found 562.3445.
2
66.4 (CH2ÀO), 70.6 (d, CHÀN, JCÀP =3.0 Hz), 125.3–146.1 ppm (aro-
matic C); TOF-MS (ESI+): m/z: calcd for C34H46NO3P: 548.3489
[M+H]+; found 548.3288.
L4e: Yield: 324 mg (58%); 31P NMR (C6D6): d=144.7 ppm (s);
L6e: Yield: 362 mg (64%); 31P NMR (C6D6): d=131.1 ppm (s);
1H NMR (C6D6): d=1.46 (s, 9H, CH3, tBu), 1.55 (s, 9H, CH3, tBu), 1.64
(s, 3H, CH3), 1.71 (s, 3H, CH3), 2.02 (s, 3H, CH3), 2.03 (s, 3H, CH3),
2.06 (s, 6H, CH3, NMe2), 3.6 (m, 1H, CHÀN), 3.8 (m, 1H, CH2ÀO), 4.0
(m, 1H, CH2ÀO), 6.95–7.2 ppm (m, 7H, CH=); 13C NMR (C6D6): d=
16.1 (CH3), 16.3 (CH3), 20.0 (CH3), 20.1 (CH3), 30.9 (CH3, tBu), 31.2 (d,
CH3,tBu, JCÀP =5.3 Hz), 34.5 (C, tBu), 34.6 (C, tBu), 42.9 (CH3, NMe2),
3
1H NMR (C6D6): d=0.4 (d, 3H, CH3, JHÀH =7.2 Hz), 1.29 (s, 9H, CH3,
tBu), 1.67 (s, 9H, CH3, tBu), 1.68 (s, 3H, CH3), 1.72 (s, 3H, CH3), 2.07
(s, 3H, CH3), 2.09 (s, 3H, CH3), 2.11 (s, 6H, CH3, NMe2), 2.65 (m, 1H,
CHÀN), 4.95 (m, 1H, CHÀO), 7.05–7.25 ppm (m, 7H, CH=); 13C NMR
(C6D6): d=7.5 (CH3), 16.2 (CH3), 16.3 (CH3), 19.9 (CH3), 20.1 (CH3),
30.9 (d, CH3, tBu, JCÀP =4.6 Hz), 31.4 (CH3, tBu), 34.5 (C, tBu), 34.6 (C,
tBu), 42.0 (CH3, NMe), 42.3 (CH3, NMe), 64.8 (CHÀN), 78.7 (d, CHÀO,
2JCÀP =13.9 Hz), 127.3–146.7 ppm (aromatic C); TOF-MS (ESI+): m/z:
calcd for C35H48NO3P: 562.3442 [M+H]+; found 562.3445.
2
66.1 (CH2ÀO), 70.6 (d, CHÀN, JCÀP =2.3 Hz), 125.3–146.1 ppm (aro-
matic C); TOF-MS (ESI+): m/z: calcd for C34H46NO3P: 548.3287
[M+H]+; found 548.3288.
L4 f: Yield: 467 mg (73%); 31P NMR (C6D6): d=143.7 ppm (s);
1H NMR (C6D6): d=0.47 (s, 9H, CH3, SiMe3), 0.52 (s, 9H, CH3, SiMe3),
3
General procedure for the preparation of [Pd(h3-allyl)-
(P-S)]BF4 (53–57)
0.64 (d, 3H, CH3, JHÀH =6.8 Hz), 2.02 (s, 6H, CH3, NMe2), 3.0 (m, 1H,
3
3
CHÀN), 5.1 (dd, 1H, CHÀO, JHÀH =6.8 Hz; JHÀP =10.4 Hz), 6.82–7.27
(m, 5H, CH=), 7.7 (m, 2H, CH=), 8.0 (s, 1H, CH=), 8.1 ppm (s, 1H,
CH=); 13C NMR (C6D6): d=À0.0 (CH3, SiMe3), 9.11 (CH3), 41.4 (CH3,
The ligand (0.05 mmol) and the complex [Pd(m-Cl)(h3--1,3-allyl)]2
(0.025 mmol) were dissolved in CD2Cl2 (1.5 mL) at RT under Ar.
AgBF4 (9.8 mg, 0.05 mmol) was added after 30 min, and the mix-
ture was stirred for 30 min. The mixture was then filtered through
3
NMe2), 63.9 (d, CHÀN, JCÀP =3.1 Hz), 78.7 (CHÀO), 122.0–152.8 ppm
(aromatic C); TOF-MS (ESI+): m/z: calcd for C37H44NO3PSi2: 638.2665
[M+H]+; found 638.2670.
ChemCatChem 2015, 7, 4091 – 4107
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Full Papers
Celite under Ar, and the resulting solutions were analyzed by NMR
spectroscopy. The complexes were precipitated as pale yellow
solids by adding hexane.
[Pd(h3--1,3-diphenylallyl)(L5e)]BF4 (55): endo isomer (33%):
31P NMR (CD2Cl2, 298 K): d=132.7 ppm (s, 1P); 1H NMR (CD2Cl2,
298 K): d=1.45 (s, 9H, CH3, tBu), 1.68 (s, 3H, CH3ÀAr), 1.71 (s, 3H,
CH3ÀAr), 1.73 (s, 9H, CH3, tBu), 2.11 (s, 3H, CH3ÀAr), 2.30 (s, 3H,
CH3ÀAr), 2.32 (s, 3H, CH3ÀN), 2.42 (m, 1H, CH2), 2.70 (s, 3H, CH3À
[Pd(h3--1,3-diphenylallyl)(L4d)]BF4 (53): endo isomer (77%):
31P NMR (CD2Cl2, 298 K): d=136.8 ppm (s, 1P); 1H NMR (CD2Cl2,
298 K): d=0.50 (d, 3H, CH3, 3JHÀH =6.8 Hz), 1.22 (s, 9H, CH3, tBu),
1.47 (s, 3H, CH3ÀAr), 1.66 (s, 3H, CH3ÀAr), 1.71 (s, 9H, CH3, tBu),
2.13 (s, 3H, CH3ÀAr), 2.29 (s, 3H, CH3ÀAr), 2.75 (s, 3H, CH3ÀN), 2.76
(s, 3H, CH3ÀN), 3.19 (m, 1H, CHÀN), 5.35 (dd, 1H, CH allyl trans to
3
3
N), 3.56 (dd, 1H, CH2, JHÀH =10.0 Hz, JHÀP =14.4 Hz), 4.49 (m, 1H,
CH allyl trans to N), 4.84 (m, 1H, CH allyl trans to P), 5.23 (m, 1H,
CHÀO), 6.19 (m, 1H, CH allyl central), 6.7–7.8 ppm (m, 17H, CH=);
13C NMR (C6D6, 298 K): d=16.5 (CH3, Ar), 16.7 (CH3, Ar), 20.0 (CH3,
Ar), 20.1 (CH3, Ar), 31.9 (CH3, tBu), 32.4 (d, CH3, tBu, JCÀP =4.6 Hz),
34.4–35.3 (C, tBu), 48.7 (CH3ÀN), 54.3 (CH3ÀN), 69.8 (m, CH allyl
trans to N), 70.9 (CH2), 74.8 (CHÀO), 93.8 (d, CH allyl trans to P,
3
3
N, JHÀH =12.0 Hz, JHÀP =4.4 Hz), 5.64 (dd, 1H, CH allyl trans to P,
3
3
3JHÀH =12.0 Hz, JHÀP =16.4 Hz), 5.79 (dd, 1H, CHÀO, JHÀH =4.8 Hz,
J
CÀP =39.7 Hz), 114.1 (d, CH allyl central, JCÀP =12.2 Hz), 125–
J
CÀP =7.2 Hz), 6.68 (m, 1H, CH allyl central), 6.9–7.8 ppm (m, 17H,
146 ppm (aromatic C). exo isomer (67%): 31P NMR (CD2Cl2, 298 K):
CH=); 13C NMR (C6D6, 298 K): d=10.4 (CH3), 16.7 (CH3, Ar), 16.8
(CH3, Ar), 20.5 (CH3, Ar), 20.7 (CH3, Ar), 32.0 (CH3, tBu), 32.3 (CH3,
tBu), 35.0–35.8 (C, tBu), 42.9 (CH3ÀN), 48.6 (CH3ÀN), 73.5 (CHÀN),
1
d=130.3 ppm (s, 1P); H NMR (CD2Cl2, 298 K): d=1.31 (s, 9H, CH3,
tBu), 1.60 (s, 9H, CH3, tBu), 1.62 (s, 3H, CH3ÀAr), 1.74 (s, 3H, CH3À
Ar), 2.16 (s, 6H, CH3-Ar and CH3ÀN), 2.45 (s, 3H, CH3ÀAr), 2.52 (m,
1H, CH2), 2.75 (s, 3H, CH3ÀN), 3.19 (dd, 1H, CH2, 3JHÀH =9.6 Hz,
3JHÀP =14.4 Hz), 4.52 (m, 1H, CH allyl trans to N), 5.30 (m, 1H, CHÀ
O), 5.61 (m, 1H, CH allyl trans to P), 6.54 (m, 1H, CH allyl central),
6.7–7.8 ppm (m, 17H, CH=); 13C NMR (C6D6, 298 K): d=16.2 (CH3,
Ar), 16.7 (CH3, Ar), 20.0 (CH3, Ar), 20.2 (CH3, Ar), 31.6 (CH3, tBu), 32.1
(CH3, tBu), 34.4–35.3 (C, tBu), 49.9 (CH3ÀN), 51.6 (CH3ÀN), 69.8 (m,
CH allyl trans to N), 71.2 (CH2), 75.6 (CHÀO), 105.6 (d, CH allyl trans
to P, JCÀP =32.0 Hz), 112.3 (d, CH allyl central, JCÀP =10.7 Hz), 125–
146 ppm (aromatic C); elemental analysis calcd (%) for
C49H59BF4NO3PPd (933.3297): C 63.00, H 6.37, N 1.50; found: C
59.61, H 6.31, N 1.46.
79.2 (d, CH allyl trans to N, JCÀP =8.3 Hz), 84.6 (d, CHÀO, JCÀP
=
11.5 Hz), 105.3 (d, CH allyl trans to P, JCÀP =33.8 Hz), 114.8 (d, CH
allyl central, JCÀP =12.2 Hz), 123–145 ppm (aromatic C). exo isomer
(23%): 31P NMR (CD2Cl2, 298 K): d=132.9 ppm (s, 1P); 1H NMR
3
(CD2Cl2, 298 K): d=0.50 (d, 3H, CH3, JHÀH =6.8 Hz), 0.91 (s, 9H, CH3,
tBu), 1.59 (s, 3H, CH3ÀAr), 1.74 (s, 3H, CH3ÀAr), 1.79 (s, 9H, CH3,
tBu), 2.17 (s, 6H, CH3ÀN and CH3ÀAr), 2.21 (s, 3H, CH3ÀN), 2.43 (s,
3H, CH3ÀAr), 3.10 (m, 1H, CHÀN), 4.50 (m, 1H, CH allyl trans to N),
5.22 (m, 1H, CHÀO), 5.45 (m, 1H, CH allyl trans to P), 6.59 (m, 1H,
CH allyl central), 6.9–7.8 ppm (m, 17H, CH=); 13C NMR (C6D6, 298 K):
d=10.1 (CH3), 17.1 (CH3, Ar), 17.3 (CH3, Ar), 20.4 (CH3, Ar), 20.8
(CH3, Ar), 31.9 (CH3, tBu), 32.8 (CH3, tBu), 35.0–35.8 (C, tBu), 38.8
(CH3ÀN), 50.5 (CH3ÀN), 71.8 (d, CH allyl trans to N, JCÀP =9.2 Hz),
72.1 (CHÀN), 84.0 (d, CHÀO, JCÀP =9.1 Hz), 99.3 (d, CH allyl trans to
P, JCÀP =33.0 Hz), 113.4 (d, CH allyl central, JCÀP =14.0 Hz), 123–
145 ppm (aromatic C); elemental analysis calcd (%) for
C50H61BF4NO3PPd (947.3453): C 63.33, H 6.48, N 1.48; found: C
63.12, H 6.43, N 1.45.
[Pd(h3--1,3-cyclohexenylallyl)(L4e)]BF4 (56): endo isomer (91%):
31P NMR (CD2Cl2, 298 K): d=134.4 ppm (s, 1P); 1H NMR (CD2Cl2,
298 K): d=0.74 (d, 3H, CH3, 3JHÀH =6.8 Hz), 1.2–1.6 (m, 4H, CH2),
1.46 (s, 9H, CH3, tBu), 1.54 (s, 9H, CH3, tBu), 1.69 (s, 3H, CH3ÀAr),
1.80 (m, 1H, CH2), 1.87 (s, 3H, CH3ÀAr), 2.21 (m, 1H, CH2), 2.23 (s,
3H, CH3ÀAr), 2.34 (s, 3H, CH3ÀAr), 2.82 (s, 3H, CH3ÀN), 3.24 (s, 3H,
CH3ÀN), 3.31 (m, 1H, CH allyl trans to N), 3.38 (m, 1H, CHÀN), 4.97
[Pd(h3--1,3-diphenylallyl)(L4e)]BF4 (54): endo isomer (17%):
31P NMR (CD2Cl2, 298 K): d=129.8 ppm (s, 1P); 1H NMR (CD2Cl2,
298 K): d=0.43 (d, 3H, CH3, 3JHÀH =6.8 Hz), 1.33 (s, 9H, CH3, tBu),
1.66 (s, 3H, CH3ÀAr), 1.74 (s, 9H, CH3, tBu), 1.84 (s, 3H, CH3ÀN), 2.14
(s, 3H, CH3ÀAr), 2.23 (s, 3H, CH3ÀAr), 2.26 (s, 3H, CH3ÀN), 2.40 (s,
3H, CH3ÀAr), 3.40 (m, 1H, CHÀN), 3.72 (dd, 1H, CH allyl trans to N,
3
3
(dd, 1H, CHÀO, JHÀH =7.2 Hz, JHÀP =12 Hz), 5.49 (m, 1H, CH allyl
central), 5.96 (m, 1H, CH allyl trans to P), 7.2–7.5 ppm (m, 7H, CH=
);13C NMR (C6D6, 298 K): d=9.9 (CH3), 16.7 (CH3, Ar), 20.5 (CH3, Ar),
20.6 (CH3, Ar), 21.4 (b, CH2), 27.4 (b, CH2), 21.4 (d, CH2, JCÀP
=
8.4 Hz), 31.7 (CH3, tBu), 32.0 (CH3, tBu), 35.2–35.4 (C, tBu), 44.8
(CH3ÀN), 53.4 (CH3ÀN), 64.7 (d, CH allyl trans to N, JCÀP =10 Hz),
69.7 (CHÀN), 82.7 (d, CHÀO, JCÀP =6.1 Hz), 109.2 (d, CH allyl trans to
P, JCÀP =40 Hz), 113.5 (d, CH allyl central, JCÀP =10.7 Hz), 127–
145 ppm (aromatic C). exo isomer (9%): 31P NMR (CD2Cl2, 298 K):
3
3JHÀH =10.2 Hz, JHÀP =6.8 Hz), 4.40 (m, 1H, CH allyl trans to P), 5.54
(m, 1H, CHÀO), 6.60 (m, 1H, CH allyl central), 6.8–7.8 ppm (m, 17H,
CH=); 13C NMR (C6D6, 298 K): d=10.8 (CH3), 16.7 (CH3, Ar), 17.0
(CH3, Ar), 20.5 (CH3, Ar), 20.6 (CH3, Ar), 32.2 (d, CH3, tBu, JCÀP
=
1
d=133.0 ppm (s, 1P); H NMR (CD2Cl2, 298 K): d=0.72 (d, 3H, CH3,
6.3 Hz), 32.5 (CH3, tBu), 35.0–35.8 (C, tBu), 43.0 (CH3ÀN), 49.1 (CH3À
N), 67.3 (d, CH allyl trans to N, JCÀP =12.8 Hz), 68.7 (CHÀN), 84.9
(CHÀO), 108.6 (d, CH allyl trans to P, JCÀP =32.4 Hz), 114.5 (d, CH
allyl central, JCÀP =12.4 Hz), 127–145 ppm (aromatic C). exo isomer
(83%): 31P NMR (CD2Cl2, 298 K): d=128.7 ppm (s, 1P); 1H NMR
3JHÀH =6.8 Hz), 1.2–1.6 (m, 4H, CH2), 1.45 (s, 9H, CH3, tBu), 1.54 (s,
9H, CH3, tBu), 1.62 (s, 3H, CH3ÀAr), 1.80 (m, 1H, CH2), 1.89 (s, 3H,
CH3ÀAr), 2.21 (m, 1H, CH2), 2.27 (s, 3H, CH3ÀAr), 2.29 (s, 3H, CH3À
Ar), 2.68 (s, 3H, CH3ÀN), 3.20 (s, 3H, CH3ÀN), 3.36 (m, 1H, CH allyl
trans to N), 3.42 (m, 1H, CHÀN), 5.21 (m, 1H, CHÀO), 5.68 (m, 1H,
CH allyl central), 6.08 (m, 1H, CH allyl trans to P), 7.2–7.5 ppm (m,
7H, CH=); 13C NMR (C6D6, 298 K): d=9.2 (CH3), 16.7 (CH3, Ar), 16.8
(CH3, Ar), 20.4 (CH3, Ar), 20.6 (CH3, Ar), 21.4 (b, CH2), 27.4 (b, CH2),
21.4 (d, CH2, JCÀP =8.4 Hz), 31.5 (CH3, tBu), 31.6 (CH3, tBu), 35.2–35.4
(C, tBu), 45 (CH3ÀN), 52.8 (CH3ÀN), 64.2 (d, CH allyl trans to N,
3
(CD2Cl2, 298 K): d=0.54 (d, 3H, CH3, JHÀH =7.2 Hz), 1.34 (s, 9H, CH3,
tBu), 1.62 (s, 3H, CH3ÀAr), 1.78 (s, 9H, CH3, tBu), 2.11 (s, 3H, CH3À
Ar), 2.19 (s, 3H, CH3ÀAr), 2.40 (s, 3H, CH3ÀN), 2.42 (s, 3H, CH3ÀAr),
2.61 (s, 3H, CH3ÀN), 3.16 (m, 1H, CHÀN), 4.40 (m, 1H, CH allyl trans
to N), 5.03 (m, 1H, CHÀO), 5.73 (m, 1H, CH allyl trans to P), 6.60 (m,
1H, CH allyl central), 6.9–7.8 ppm (m, 17H, CH=); 13C NMR (C6D6,
298 K): d=9.7 (CH3), 16.9 (CH3, Ar), 17.3 (CH3, Ar), 20.5 (CH3, Ar),
20.7 (CH3, Ar), 32.0 (CH3, tBu), 32.6 (CH3, tBu), 35.0–35.8 (C, tBu),
J
CÀP =9.2 Hz), 69.7 (CHÀN), 81.9 (d, CHÀO, JCÀP =7.3 Hz), 110.8 (d,
CH allyl trans to P, JCÀP =38.6 Hz), 113.2 (d, CH allyl central, JCÀP
=
9.6 Hz), 127–145 ppm (aromatic C); elemental analysis calcd (%) for
C41H57BF4NO3PPd (835.3140): C 58.90, H 6.87, N 1.68; found: C
58.21, H 6.84, N 1.65.
42.9 (CH3ÀN), 48.8 (CH3ÀN), 67.5 (d, CH allyl trans to N, JCÀP
12.6 Hz), 69.4 (CHÀN), 81.4 (CHÀO), 110.6 (d, CH allyl trans to P,
CÀP =30.6 Hz), 113.5 (d, CH allyl central, JCÀP =13.8 Hz), 123–
=
J
145 ppm (aromatic C); elemental analysis calcd (%) for
C50H61BF4NO3PPd (947.3453): C 63.33, H 6.48, N 1.48; found: C
63.02, H 6.43, N 1.44.
[Pd(h3--1,3-cyclohexenylallyl)(L5e)]BF4 (57):[34] endo isomer (96%):
31P NMR (CD2Cl2, 298 K): d=135.2 ppm (s, 1P); 1H NMR (CD2Cl2,
ChemCatChem 2015, 7, 4091 – 4107
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ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Papers
298 K): d=1.25 (m, 1H, CH2), 1.43 (m, 2H, CH2), 1.45 (s, 9H, CH3,
tBu), 1.54 (s, 9H, CH3, tBu), 1.70 (m, 1H, CH2), 1.73 (s, 3H, CH3ÀAr),
Typical procedure for the allylic amination of S1
A degassed solution of [PdCl(h3-C3H5)]2 (0.9 mg, 0.0025 mmol) and
the corresponding amino phosphite ligand (0.0055 mmol) in di-
chloromethane (0.5 mL) was stirred for 30 min. Subsequently, a so-
lution of S1 (0.5 mmol) in dichloromethane (1.5 mL) and benzyla-
mine (131 mL, 1.5 mmol) were added. The reaction mixture was
stirred at RT. After the desired reaction time, the reaction mixture
was diluted with Et2O (5 mL), and saturated NH4Cl (aq) (25 mL) was
added. The mixture was extracted with Et2O (3”10 mL), and the
extract was dried over MgSO4. The conversion was measured by
1H NMR spectroscopy, and the ee was determined by HPLC. For de-
tails of the characterization and determination of ee see Support-
ing Information.
1.88 (s, 3H, CH3ÀAr), 1.90 (m, 1H, CH2), 2.16 (m, 1H, CH2), 2.24 (s,
3
3H, CH3ÀAr), 2.35 (s, 3H, CH3ÀAr), 2.71 (d, 1H, CH2ÀN, JHÀH
=
14.4 Hz), 2.90 (s, 3H, CH3ÀN), 3.12 (s, 3H, CH3ÀN), 3.42 (dd, 1H,
3
3
CH2ÀN, JHÀH =14.4 Hz, JHÀP =9.6 Hz), 3.49 (m, 1H, CH allyl trans to
N), 5.23 (m, 1H, CHÀO), 5.44 (m, 1H, CH allyl central), 6.03 (m, 1H,
CH allyl trans to P), 7.2–7.5 ppm (m, 7H, CH=);13C NMR (C6D6,
298 K): d=16.7 (CH3, Ar), 16.8 (CH3, Ar), 20.5 (CH3, Ar), 20.6 (CH3,
Ar),), 20.9 (d, CH2, JCÀP =2.3 Hz), 27.6 (b, CH2), 28.5 (d, CH2, JCÀP
=
7.6 Hz),31.8 (CH3, tBu), 32.0 (d, CH3, tBu, JCÀP =1.5 Hz)), 35.2 (C, tBu),
35.5 (C, tBu), 51.8 (CH3ÀN), 56.7 (CH3ÀN), 67.6 (d, CH allyl trans to
N, JCÀP =9.1 Hz), 71.8 (CHÀN), 77.9 (d, CHÀO, JCÀP =6.8 Hz), 105.0
(d, CH allyl trans to P, JCÀP =40.3 Hz), 113.5 (d, CH allyl central,
J
CÀP =10.6 Hz), 126–146 ppm (aromatic C). exo isomer (4%):
31P NMR (CD2Cl2, 298 K): d=134.2 ppm (s, 1P); 1H NMR (CD2Cl2,
298 K): d=1.25 (m, 1H, CH2), 1.43 (m, 2H, CH2), 1.47 (s, 9H, CH3,
tBu), 1.54 (s, 9H, CH3, tBu), 1.70 (m, 1H, CH2), 1.74 (s, 3H, CH3ÀAr),
1.90 (bs, 4H, CH3-Ar and CH2), 2.16 (m, 1H, CH2), 2.24 (s, 3H, CH3À
Typical procedure for the allylic etherification of S1
A degassed solution of [PdCl(h3-C3H5)]2 (0.9 mg, 0.0025 mmol) and
the corresponding amino phosphite ligand (0.0055 mmol) in di-
chloromethane (0.5 mL) was stirred for 30 min. Subsequently, a so-
lution of the corresponding substrate (31.5 mg, 0.125 mmol) in di-
chloromethane (1.5 mL) was added. After 10 min, Cs2CO3 (122 mg,
0.375 mmol) and alkyl alcohol (0.375 mmol) were added. The reac-
tion mixture was stirred at RT. After the desired reaction time, the
reaction mixture was diluted with Et2O (5 mL), and saturated NH4Cl
(aq) (25 mL) was added. The mixture was extracted with Et2O (3”
10 mL), and the extract was dried over MgSO4. The conversion was
3
Ar), 2.35 (s, 3H, CH3ÀAr), 2.81 (d, 1H, CH2ÀN, JHÀH =14.0 Hz), 2.91
3
(s, 3H, CH3ÀN), 3.09 (s, 3H, CH3ÀN), 3.27 (dd, 1H, CH2ÀN, JHÀH
=
14.0 Hz, 3JHÀP =8.4 Hz), 3.39 (m, 1H, CH allyl trans to N), 5.39 (m,
1H, CHÀO), 5.54 (m, 1H, CH allyl central), 5.84 (m, 1H, CH allyl
trans to P), 7.2–7.5 ppm (m, 7H, CH=); elemental analysis calcd (%)
for C40H55BF4NO3PPd (821.2984): C 58.44, H 6.74, N 1.70; found: C
58.06, H 6.70, N 1.67.
1
measured by H NMR spectroscopy. HPLC was used to determine
the ee. For details of the characterization and determination of ee
Study of the reactivity of the [Pd(h3-allyl)(L)]BF4 with sodium
malonate by in situ NMR spectroscopy[35]
see Supporting Information.
A solution of in situ prepared [Pd(h3-allyl)(L)]BF4 (L=phosphite pyri-
dine, 0.05 mmol) in CD2Cl2 (1 mL) was cooled in the NMR spec-
trometer to À808C. At this temperature, a solution of cooled
sodium malonate (0.1 mmol) was added. The reaction was then fol-
lowed by 31P NMR spectroscopy. The relative reaction rates were
calculated using a capillary that contained a solution of triphenyl-
phosphine in CD2Cl2 as the external standard.
Typical procedure for the preparation of carbocycles 46–51
A solution of Grubbs II catalyst (5 mg, 0.006 mmol) and the corre-
sponding alkylated product (0.12 mmol) in CH2Cl2 (3 mL) was
stirred for 16 h. The solution was purified directly by flash chroma-
tography (95:5; Hex/EtOAc) to obtain the desired carbocycle. For
details of the characterization and determination of ee see Sup-
porting Information.
Acknowledgements
Typical procedure for the allylic alkylation of linear (S1 and
S3–S8) and cyclic (S2, S9, and S10) substrates
We would like to thank the Spanish Government for providing
grant CTQ2013-40568P, the Catalan Government for grant
2014SGR670, COST action CM 1205 Catalytic Routines for Small
Molecule Activation (CARISMA), and the ICREA Foundation for
providing M.D. and O.P. with financial support through the ICREA
Academia awards.
A degassed solution of [PdCl(h3-C3H5)]2 (0.9 mg, 0.0025 mmol) and
the corresponding amino phosphite (0.0055 mmol) in dichlorome-
thane (0.5 mL) was stirred for 30 min. Subsequently, a solution of
the corresponding substrate (0.5 mmol) in dichloromethane
(1.5 mL), nucleophile (1.5 mmol), N,O-bis(trimethylsilyl)acetamide
(370 mL, 1.5 mmol), and KOAc (3 mg, 0.03 mmol) was added. The
reaction mixture was stirred at RT. After the desired reaction time,
the reaction mixture was diluted with Et2O (5 mL) and saturated
NH4Cl (aq) (25 mL) was added. The mixture was extracted with
Et2O (3”10 mL), and the extract was dried over MgSO4. For 12,
14–21, 27–32, 35, 37–39, and 45, the solvent was removed, con-
versions were measured by 1H NMR spectroscopy, and ee values
were determined by HPLC. For 13, 33–34, 40–41, and 43–44, the
conversion and ee were determined by GC. For 36 and 42, conver-
Keywords: allylic compounds · asymmetric catalysis · ligand
design · ligand effects · palladium
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1
termined by H NMR spectroscopy using [Eu(hfc)3], hfc=[3-(hepta-
fluoropropylhydroxymethylene)-(+)-camphorate]. For details of the
characterization and determination of ee see Supporting Informa-
tion.
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Full Papers
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of S1. If the ee is to be high, the ligand must create a small chiral
pocket around the metal center, mainly because of the presence of less
sterically demanding methyl syn substituents.
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Received: August 5, 2015
Published online on October 14, 2015
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