Asymmetric Catalysis in Liquid Confinement: Probing the Performance of Novel Chiral Rhodium–Diene Complexes in Microemulsions and Conventional Solvents

Article abstract of DOI:10.1002/chem.201900947

The role of liquid confinement on the asymmetric Rh catalysis was studied using the 1,2-addition of phenylboroxine (2) to N-tosylimine 1 in the presence of [RhCl(C₂H₄)₂]₂ and chiral diene ligands as benchmark reaction. To get access to Rh complexes of different polarity, enantiomerically pure C₂-symmetric p-substituted 3,6-diphenylbicyclo[3.3.0]octadienes 4 and diastereomerically enriched unsymmetric norbornadienes 5 and 6 carrying either the Evans or the SuperQuat auxiliary were synthesized. A microemulsion containing the equal amounts of H₂O/KOH and toluene/reactants was formulated using the hydrophilic sugar surfactant n-octyl β-d-glucopyranoside (C₈G₁) to mediate the miscibility between the nonpolar reactants and KOH, needed to activate the Rh–diene complex. Prominent features of this organized reaction medium are its temperature insensitivity as well as the presence of water and toluene-rich compartments with a domain size of 55 ? confirmed by small-angle X-ray scattering (SAXS). Although bicyclooctadiene ligands 4 a,b,e performed equally well under homogeneous and microemulsion conditions, ligands 4 c,d gave a different chemoselectivity. For norbornadienes 5, 6, however, microemulsions markedly improved conversion and enantioselectivity as well as reaction rate, as was confirmed by kinetic studies using ligand 5 b.

Full text of DOI:10.1002/chem.201900947

A Journal of
Accepted Article
Title: Asymmetric Catalysis in Liquid Confinement: Probing the
Performance of Novel Chiral Rhodium Diene Complexes in
Microemulsions and Conventional Solvents
Authors: Max Deimling, Manuel Kirchhof, Barbara Schwager, Yaseen
Qawasmi, Alex Savin, Tina Mühlhäuser, Wolfgang Frey, Birgit
Claasen, Angelika Baro, Thomas Sottmann, and Sabine
Laschat
This manuscript has been accepted after peer review and appears as an
Accepted Article online prior to editing, proofing, and formal publication
of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
published online in Early View as soon as possible and may be different
to this Accepted Article as a result of editing. Readers should obtain
the VoR from the journal website shown below when it is published
to ensure accuracy of information. The authors are responsible for the
content of this Accepted Article.
To be cited as: Chem. Eur. J. 10.1002/chem.201900947
Link to VoR: http://dx.doi.org/10.1002/chem.201900947
Supported by

10.1002/chem.201900947
Chemistry - A European Journal
Asymmetric Catalysis in Liquid Confinement: Probing the Performance of Novel Chiral
Rhodium Diene Complexes in Microemulsions and Conventional Solvents
Max Deimling+,[a] Manuel Kirchhof+,[a] Barbara Schwager+,[b] Yaseen Qawasmi+,[b] Alex Savin,[a]
Tina Mühlhäuser,[a] Wolfgang Frey,[a] Birgit Claasen,[a] Angelika Baro,[a] Thomas Sottmann,*[b]
and Sabine Laschat*[a]
Abstract: The role of liquid confinement on the asymmetric Rh catalysis was studied using the
1,2-addition of phenylboroxine 2 to N-tosylimine 1 in the presence of [RhCl(C2H4)2]2 and chiral
diene ligands as benchmark reaction. To get access to Rh complexes of different polarity,
enantiomerically pure C2-symmetric p-substituted 3,6-diphenylbicyclo[3.3.0]octadienes 4 and
diastereomerically enriched unsymmetric norbornadienes 5 and 6 carrying either the Evans or the
SuperQuat auxiliary were synthesized. A microemulsion containing the equal amounts of
H2O/KOH and toluene/reactants was formulated using the hydrophilic sugar surfactant n-octyl β-
ᴅ-glucopyranoside (C8G1) to mediate the miscibility between the nonpolar reactants and KOH,
needed to activate the Rh diene complex. Prominent features of this organized reaction medium
are its temperature insensitivity as well as the presence of water and toluene-rich compartments
with a domain size of 55 Å confirmed by SAXS. While bicyclooctadiene ligands 4a,b,e
performed equally well under homogeneous and microemulsion conditions, ligands 4c,d gave a
different chemoselectivity. For norbornadienes 5, 6, however, microemulsions markedly
improved conversion and enantioselectivity as well as reaction rate, as was confirmed by kinetic
studies using ligand 5b.
[a] M. Deimling,+ M. Kirchhof,+ A. Savin, Dr. T. Mühlhäuser, Dr. W. Frey,
Dr. B. Claasen, Dr. A. Baro, Prof. S. Laschat
Institut für Organische Chemie, Universität Stuttgart,
Pfaffenwaldring 55, D-70569 Stuttgart (Germany)
E-mail: sabine.laschat@oc.uni-stuttgart.de
[b] B. Schwager,+ Y. Qawasmi,+ Prof. T. Sottmann
Institut für Physikalische Chemie, Universität Stuttgart,
Pfaffenwaldring 55, D-70569 Stuttgart (Germany)
E-mail: t.sottmann@ipc.uni-stuttgart.de
[+] These coauthors contributed equally to this work.
 Supporting Information and the ORCID identification number(s) for the author(s) of this
article can be found under https://
1
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
Introduction
Microemulsions are thermodynamically stable and macroscopically homogeneous mixtures of at
least two immiscible and an amphiphilic component. Contrary to regular solutions, micro-
emulsions are composed of nanometer-scaled water and oil-domains separated by a surfactant
monolayer. Adjusting the properties of the amphiphilic film by e.g. temperature, pressure, co-
surfactant/surfactant ratio or electrolyte concentration a variety of nanostructures are accessible
ranging from spherical over cylindrical droplets to network-like and bicontinuous structures.[1,2]
Due to their ability to overcome the reactants incompatibility faced in organic synthesis and the
enormous internal interfacial area,[3] they were widely used in organic syntheses instead of
conventional solvents to mediate the miscibility between polar and nonpolar reactants. Thus
increased reaction rates and enhanced yields compared to two-phase systems were achieved.[4]
Over the last decade homogeneous metal catalysis has strongly benefited from microemul-
sions due to improved solubility of reactants and mass transport as compared to conventional
solvents or biphasic reaction media.[5] Most work has focused on industrially relevant transition
metal-catalyzed reactions in microemulsions,[6] such as Rh-catalyzed hydrogenations and
hydroformylations,[7–10] Rh- and Pd-catalyzed disproportionation of dihydroarenes,[11] Rh-
catalyzed cyclotrimerizations of alkynes,[12] photocatalytic water splitting with Ir and Rh
complexes[13] as well as biocatalytic reactions.[14,15] Besides the use of various enzymes[11,12]
surprisingly little work has been carried out on homogeneous asymmetric catalysis in
microemulsions. Among the few examples are a vitamin B12-catalyzed epoxide isomerization
towards an allylic alcohol reported by Rusling.[16] Both the product ratio and the enantio-
selectivity were found to depend on the type of microemulsion and surfactant. On the other hand,
Lipshutz demonstrated in the asymmetric Au-catalyzed lactonization of allenic acids in
microemulsions the role of the chiral phosphane ligand on the ee values.[17]
2
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
Asymmetric catalysis with chiral Rh diene complexes has experienced much progress over the
last two decades[18] since Hayashi’s,[19] Carreira’s[20] and Grützmacher’s[21] ground-braking dis-
coveries. Since then a broad range of chiral diene ligands has been developed, most prominently
bicyclic dienes,[22,23] but also acyclic[24,25] and planar chiral dienes.[26] Rh- and Ir-complexes
carrying chiral diene ligands turned out to be particularly successful for asymmetric C–C, C–O
and C–N bond formations,[27–29,30] but also cycloadditions,[31,32] reductions[33] and other more
complex transformations[34] have been realized. Mechanistic insight was obtained by several
theoretical studies.[23a,35] While asymmetric catalytic reactions in micellar systems were
successfully performed,[36] asymmetric catalysis with Rh diene complexes in bicontinuous micro-
emulsions have not been reported so far. Therefore, we probed for the first time the influence of
microemulsions as organized reaction media for the Rh-catalyzed asymmetric arylation of N-
tosylimines 1 with the organoboron reagent 2 to the corresponding secondary amines 3 as
benchmark reaction. Moreover, this benchmark system contains multi-components as e.g.
aqueous/organic solvent mixtures, bases and/or salts, which often requires tedious reaction
optimization due to sluggish reaction rates and poor yields.[23a,25,37] Thus, we anticipated that
particularly bicontinuously structured microemulsions should overcome limitations of
conventional solvents caused by mass transport due to the simultaneous existence of polar and
nonpolar nano-domains controlling the catalyst–substrate interactions. In addition, the location of
reactant, base as well as catalyst and ligands within either the polar or nonpolar nano-domains or
the surfactant film of the microemulsion will have a strong influence on the catalytic reaction. In
order to get access to Rh complexes of different polarity, we synthesized two series of novel
chiral diene ligands 4–6 being suitable for this purpose. Ligands 4 were chosen because the
concave diarylbicyclo[3.3.0]octadiene core creates a symmetric relatively nonpolar ligand sphere
around the Rh center, which can be manipulated by attachment of substituents at the 4-position of
3
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
the phenyl rings. On the other hand, the unsymmetric norbornadiene ligands 5 and 6 with the
attached oxazolidinone unit not only generate a less symmetric and much more polar environ-
ment around Rh, but in addition, the oxazolidinone unit might coordinate the Rh (Scheme 1).[38]
In the current report we compare the Rh catalysis in microemulsions with the one in conventional
reaction media (toluene and dioxane).
Scheme 1. Envisioned Rh-catalyzed asymmetric 1,2-additions in the presence of novel chiral bi-
cyclo[3.3.0]octadiene and norbornadiene based ligands 4–6.
Results and Discussion
Synthesis of diene ligands: The synthesis of chiral bicyclo[3.3.0]octa-1,4-dienes 4, which were
based on the known tetrahydropentalene ligand 4a,[23b,37d] commenced with Suzuki coupling
between the borolane 8[39] and bisenoltriflate 7[23b] with 10 mol% of Pd(PPh3)4 and aqueous
NaHCO3 in DME at 100°C to yield enantiomerically pure dihydroxy ligand 4e in 73% (>99% ee,
based on the enantiomeric purity of used (3aR,6aR)-4a[23b,37d] determined by GC on chiral
stationary phase. For details see Supporting Information) (Scheme 2). Williamson etherification
4
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
of 4e with hexylbromide or 6-chloro-1-hexyne in the presence of Cs2CO3 and KI in DMSO at
90°C gave enantiomerically pure ethers 4b and 4c in 78% and 90% yield, respectively. Under
Mitsunobu conditions 4e reacted with 2-[2-(prop-2-ynyloxy)ethoxy]ethanol in the presence of
PPh3 and diisopropyl azodicarboxylate (DIAD) to enantiomerically pure alkynyl-terminated
ligand 4d in 58% yield (Scheme 2).
Scheme 2. Synthesis of novel chiral bicyclo[3.3.0.]octadiene ligands 4. For details see Support-
ing Information.
The synthesis of chiral unsymmetrically substituted norbornadienes 5 and 6 carrying either the
D-valine-derived Evans oxazolidinone[40] or the corresponding sterically more demanding
SuperQuat auxiliary[41] is shown in Scheme 3. Methyl-substituted acyloxazolidinones 11a, 12a
were obtained in 28% and 52% yield, respectively, by reaction of tetrolic acid 9a[42] with pivaloyl
5
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
chloride and Et3N in THF at 0°C,[43] followed by addition of the lithiated oxazolidinone 10a,b to
the in situ formed mixed anhydride. The aryl-substituted precursors 11b,d and 12b,c were
obtained by treatment of the respective 9[42] with thionyl chloride under reflux[44] and subsequent
reaction with the lithiated oxazolidinones 10a,b in THF at –78°C.[45] After warming to room
temperature, acyloxazolidinones 11b,d and 12b,c were isolated in 40–81%.
Scheme 3. Synthesis of chiral norbornadiene oxazolidinone ligands 5 and 6 applying literature
procedures.[40,43–46] For details see Supporting Information.
The [4+2] cycloaddition of the propargyl acyloxazolidinones 11 and 12 with cyclopentadiene was
carried out in the presence of 1.6 equiv. of Et2AlCl in CH2Cl2 at –78°C and slow warming to
–20°C (Scheme 3).[40,46] Other investigated methods, however, failed (see Supporting Informa-
6
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
tion). In all cases, norbornadiene ligands 5 and 6 were obtained as diastereomeric mixtures 5, 5'
and 6, 6' consisting of the enantiomerically pure diastereomers (based on the use of enantio-
merically pure auxiliaries 10a,b) (Scheme 3). Dienes 5b, 5d, 5d' and 6b were isolated as single
diastereomers in enantiomerically pure form by recrystallization (Scheme 3).
Single crystal structure determination was possible for bicyclo[3.3.0]octa-1,4-diene 4d as well as
norbornadienes 5b, 5d' and 6b (Figures S5, S6).[47] Fortunately, X-ray crystal structure data could
also be obtained for two Rh complexes (Figure 1, Table S3).[47]
Figure 1. Structure of complexes [RhCl(6b)]2 (a) and [RhCl(5b)] (b) in the solid state. The abso-
lute configuration was determined by anomalous dispersion with relevant Flack parameters x =
–0.031(6) and 0.01(3), respectively. For getting better overall standard deviations of the geome-
tric parameters of the [RhCl(6b)]2 X-ray structure, a severely disordered Et2O solvate molecule
was removed with SQUEEZE as implemented in PLATON.[48] The Rh1···O1 and Rh1–Cl1
distances in [RhCl(5b)] are shorter than in [RhCl(6b)]2 and interactions of C8=C9, C11=C12 to
Rh elongate the double bonds.
7
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
While the SuperQuat auxiliary-derived ligand 6b formed a binuclear µ-chloro-bridged Rh
complex [RhCl(6b)]2 (Figure 1a) with bond lengths and angles, which are in good agreement
with literature data,[23a] the corresponding Evans auxiliary-derived ligand 5b formed a
mononuclear complex [RhCl(5b)] (Figure 1b), where the carbonyl group of the oxazolidinone
unit coordinates the Rh center, resulting in an elongation of the C1=O1 double bond to 1.227(4)
Å (see Supporting Information).
Formulation and optimization of the microemulsions: Often micellar systems are used as
reaction media for catalytic reactions.[36a,d] However, for the studied Rh-catalyzed asymmetric
1,2-addition we extended the micellar system by a hydrophobic component, using a thermodyna-
mically stable microemulsion as a reaction medium. Thus, a perfect solvent environment is pro-
vided for all reaction partners. The aqueous domains of the microemulsion are a good solvent for
KOH, needed to activate catalyst/ligand system; the hydrophobic reactants N-tosylimine 1 and
triphenylboroxine 2 feel fine in the toluene domains, while the catalyst/ligand system, possessing
both polar and non-polar parts, can reside in/at the amphiphilic surfactant film. Assuming that the
bicontinuous structure allows for the easiest access of the catalyst/ligand system with respect to
both KOH and the reactants, we aimed for a microemulsion containing equal amounts of water
and oil ( = 0.50). Furthermore, due to the fact that the solubility of the reactants 1 and 2 in
toluene is limited at low temperatures, a reaction temperature of T = 60.0°C was envisaged. Thus,
the bicontinuous microemulsion containing water/KOH, toluene/reactants 1 and 2 as well as the
surfactant and catalyst/ligand system should be stable around T = 60.0°C. In order to formulate
such a microemulsion, we studied the phase behaviour of the described system H2O–
cyclohexane–non-ionic surfactant[49] as starting system. To avoid the formation of liquid
crystalline phases on one hand and to decrease the temperature-sensitivity of the system on the
8
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
other hand, the pentaethylene glycol monohexyl ether (C6E5) surfactant with a shorter chain was
used instead of octaethylene glycol monodecyl ether (C10E8). The phase behaviour of the H2O–
cyclohexane–C6E5 microemulsion systems was investigated as a function of temperature and
surfactant mass fraction, i.e. recording T(γ)-sections through the phase prism at a constant mass
fraction α = 0.50 of oil in the mixture of water and oil.[1]
As shown in Figure 2, the phase boundaries show the typical behaviour of microemulsion
systems (at α = 0.50) stabilized by a non-ionic surfactant.
Figure 2. T(γ)-section of the systems H2O–cyclohexane–C6E5 () at α = 0.50 (starting system).
Schematic test tubes visualize the state of the sample at different temperatures and surfactant
̅
mass fractions . 2: coexistence of an oil-in-water microemulsion with an oil-excess phase; 2: co-
existence of water-in-oil microemulsion with a water-excess phase; 1: one phase microemulsion;
3: coexistence of microemulsion phase with water- and oil-excess phase.
At low temperatures, an oil-in-water microemulsion coexists with an oil-excess phase (denoted as
2), while at high temperatures a water-in-oil microemulsion coexists with a water-excess
̅
phase (denoted as 2). At temperatures in between, three phases, i.e. a microemulsion phase which
coexists with a water- and an oil-excess phase (denoted as 3), or a one phase microemulsion can
9
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
be observed. The pivotal point of these phase diagrams is the so-called X-point, which defines the
minimum surfactant mass fraction γ that is needed to solubilize equal amounts of water and oil
into each other at the phase inversion temperature 푇 (PIT). Note that the envisaged bicontinuous
structure is formed near the PIT at 훾 ≥ γ. The X-point of H2O–cyclohexane–C6E5 system (at α =
0.50) is located at 푇 = 57.0±0.5°C and γ = 0.285±0.005.
Based on this microemulsion, cyclohexane was replaced with toluene causing a shift of the phase
boundaries to lower temperatures. Therefore, the surfactant C6E5 was partly replaced with the
hydrophilic sugar surfactant C8G1 (n-octyl β-ᴅ-glucopyranoside) to compensate the shift to lower
temperatures. These optimization steps are shown and discussed extensively in SI (Figures S1,
S2). The phase behaviour of the obtained H2O–toluene–C6E5/C8G1 system (α = 0.50, δ = 0.70,
mass fraction of C8G1 in the surfactant mixture) is shown in Figure 3, . As can be seen, the X-
point of this system is located at 푇 = 55.8±0.5°C and γ = 0.245±0.005.
Before this toluene-microemulsion could be used as reaction medium, the influence of KOH,
catalyst and ligands as well as reactants on the phase behaviour had to be examined. The
influence of KOH and the Rh-catalyst with the two different ligands 4a and 5b on the phase
boundaries of the H2O–toluene–C6E5/C8G1 system (α = 0.50, δ = 0.70) is shown in Figure 3a. It is
apparent that a low KOH concentration (x) (ε = 0.0033) (the parameter ε is the mass fraction of
KOH in the H2O/KOH mixture), the combination of Rh-catalyst and ligand 4a () as well as Rh-
catalyst and ligand 5b () had no effect on the phase behaviour of the system.
The effect of the reactant N-tosylimine 1 on the phase behavior of the formulated toluene
microemulsion is shown in Figure 3b (). N-tosylimine 1 shifted the phase boundaries to lower
temperatures by approximately 15 K, which might be a consequence of its larger polarity com-
pared to toluene.[50] In the same manner as for N-tosylimine 1, the influence of triphenylboroxine
2 on the phase behaviour of the microemulsion was studied.
10
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
Figure 3. Influence of (a) KOH (ε = 0.0033), Rh-catalyst and ligands and (b) the reactants on the
T(γ)-section of the base system H2O–toluene–C6E5/C8G1 (δ = 0.70) () at α = 0.50 (a) and
α = 0.52 (b). Due to the small concentrations, KOH (), the Rh-catalyst with ligand 4a () and
ligand 5b () had almost no influence on the phase boundaries of the base system. (b) Contrary
reactants N-tosylimine 1 (7.1 wt%) () and triphenylboroxine 2 (8.8 % wt%) () in toluene at γ
= 0.32 and α = 0.52 strongly shifted the phase boundaries to lower temperature as well as the
mixture of 1/2 (7.1 wt%/8.8 wt% in toluene at γ = 0.32 and α = 0.54) ().
As shown in Figure 3b (), using a mixture of 2 and toluene instead of toluene the phase
̅
boundaries were shifted strongly to lower temperatures. Thus, only the upper 12 phase
boundary could be detected. This strong effect of triphenylboroxine 2 on the phase behaviour
might be related to the presumable formation of hydrolysis products as e.g. boronic acid, which
would rather act as hydrophobic co-surfactants changing the curvature of the amphiphilic film
and thus the phase behaviour of the microemulsion system. In order to prove this hypothesis, we
measured the interfacial tension between water and toluene as a function of the triphenylboroxine
concentration in toluene at T = 25°C using the pendant drop method. The interfacial tension was
found to decrease from 36 mNm–1 (value from[51]) to 12 mNm–1 with increasing triphenyl-
boroxine concentration to 2.0 wt%, which strongly indicates the formation of amphiphilic
11
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
hydrolysis products as e.g. boronic acid. The observed trends are more detailed discussed in SI
(Figure S4).
For the Rh-catalyzed asymmetric 1,2-addition a toluene microemulsion has to be formulated
containing both reactants. Therefore, also the influence of the N-tosylimine 1/triphenylboroxine 2
mixture (7.1 wt%/8.8 wt% in toluene at γ = 0.32) on the phase behaviour of the microemulsion
was studied (Figure 3b, ). The mixture of 1 and 2 shifted the phase boundaries to even lower
temperatures as expected from the trends found for the microemulsions containing only one
reactant.
Aiming for a bicontinuously structured microemulsion at T  60°C which contains KOH, Rh-
catalyst and ligands as well as the two reactants the phase boundaries had to be shifted strongly to
higher temperatures. Interestingly, replacing the remaining C6E5 surfactant with C8G1, the shift of
the phase boundaries to lower temperatures caused by 2 and 1 could be compensated. Figure 4
shows the phase behaviour of the reaction microemulsion H2O/KOH–toluene/N-tosylimine
1/triphenylboroxine 2–C8G1 with α = 0.54, εKOH = 0.0033, 1 (7.1 wt%) and 2 (8.8 wt%). The
steepness of the phase boundaries is a consequence of the weak temperature dependence of the
amphiphilic film curvature. With increasing temperature, the hydration of the hydroxyl groups
decreases, while the toluene and reactants molecules have a stronger tendency to penetrate the
alkyl chains of the amphiphilic film. As both hydration and penetration are only weakly
temperature dependent, the reaction microemulsion might also be less sensitive to composition
changes generated by the Rh-catalyzed asymmetric 1,2-addition. The X-point of the reaction
microemulsion is located at 푇 = 48.4±0.5°C and γ = 0. 19±0.005.
12
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
Figure 4. T(γ)-section of the system H2O/KOH–toluene/N-tosylimine 1/triphenylboroxine 2–
C8G1 at α = 0.54, εKOH = 0.0033, 1 (7.1 wt%) and 2 (8.8 wt%) in toluene at γ = 0.30. Due to the
weak temperature dependence of the C8G1 surfactant, a wide one-phase regime can be observed.
The Rh-catalyzed asymmetric 1,2-addition at  = 0.26 and a temperature of T = 60°C is indicated
by the star.
In order to determine the size of the water and toluene/reactant domains inside the one-phase
microemulsion, SAXS experiments were performed at  = 0.26 and T = 60°C. Figure 5 displays
the scattering data plotting the scattering intensity as a function of the scattering vector q in a
double-log plot. The scattering curves exhibit the typical shape found for bicontinuous micro-
emulsions:[52] Starting from low q-values, the scattering intensity slightly increases, runs through
a maximum at middle q-values before the intensity decreases with q–3 rather than q–4. Note that
this finding can be explained by the combination of film and bulk contrast contributions.
By using the Teubner-Strey model[52] a correlation length of TS = 3.3±0.2 nm and a size of dTS/2
= 5.5±0.2 nm was obtained for the water and toluene/reactant domains. Considering that the
concentration of the catalyst/ligand complex with respect to reactant 1 is 2.5 mol%, on average
every second toluene domain contains a catalyst/ligand complex.
13
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
Figure 5. SAXS scattering curve (black) of the one-phase microemulsion of H2O/KOH–
toluene/N-tosylimine 1/triphenylboroxine 2–C8G1 system at  = 0.26,  = 0.54, εKOH = 0.0033, 1
(7.1 wt%) and 2 (8.8 wt%) in toluene at γ = 0.30 and T = 60.0°C. The red solid line is the fit of
the scattering peak by the Teubner-Strey model.[52]
When the Rh-catalyzed asymmetric 1,2-addition was conducted in the H2O/KOH–toluene/N-
tosylimine 1/triphenylboroxine 2–C8G1 microemulsion at T = 60°C, we observed that the reaction
medium changed from the one phase to the 2 phase state, where an oil-in-water microemulsion
coexists with an oil-excess phase. In order to explore this observation, we studied the influence of
the changing reactant/product ratio on the phase behaviour of the toluene microemulsion. As can
be seen in Figure S3, replacing the two reactants 1 and 2 with the product, i.e. the corresponding
secondary amine 3, the lower 21 phase boundary indeed shifted to higher temperature. This
effect can most probably related to both the increasing amount of amine 3, which is more
hydrophobic than N-tosylimine 1 and the decreasing amount of triphenylboroxine 2
corresponding to a decreasing amount of its amphiphilic hydrolysis products which act as
hydrophobic co-surfactants.
14
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
Rh-catalyzed asymmetric 1,2-additions: The application of chiral bicyclo[3.3.0]octadienes 4 as
ligands in Rh-catalyzed asymmetric 1,2-additions of triphenylboroxine 2 to (4-chlorophenyl)-N-
tosylimine (1) was studied under homogeneous conditions and in microemulsions (Table 1). As
benchmark catalysts [Rh(COD)OH]2 and the in situ formed catalyst from [Rh(C2H4)2Cl]2 and
known (3aR,6aR)-diphenyldiene 4a were used.
Table 1. Comparison of 1,2-additions of boroxine 2 to N-tosylimine 1 in
solution and microemulsion (ME) catalyzed by a complex of Rh/ligand 4.
The progress of the reactions was monitored by 1H-NMR spectroscopy.
Entry Ligand Solvent NMR yield [%][a] Yield [%][b]
ee [%]
1
3
59
13
–
3
58
13
–
3
13
–
1
2
COD dioxane 36
0
>99
99
97
93
91
97
>99
95
93
86
97
4a
4a
4b
4c
4d
4e
4a
4b
4c
4d
4e
dioxane
toluene
dioxane
dioxane
–
–
–
1
>99
90
–
>99
82
–
–
3
10
4
9
10
–
4
96
85
–
5
61 28[c] 56
21
30
–
2
6
dioxane 33
55
98
96
87
15
35
95
2[c]
50
97
93
82
15
32
95
8
7
dioxane
ME[d]
ME[d]
ME[d]
ME[d]
ME[d]
–
2
2
5
1
1
2
–
8
2
–
–
9
11
78
64
4
–
–
10
11
12
74
60
–
5
5
–
[a] Mesitylene was used as the internal standard.[53] [b] Isolated yields. [c]
Aldehyde 14 was detected by 1H-NMR in 3% and 4% (entries 5, 6). [d]
ME: 0.60 g C8G1, 0.89 mL toluene and 0.77 mL H2O at γ = 0.26 and α =
0.54.
Under the conditions in Table 1 treatment of tosylimine 1 and phenylboroxine 2 with
[Rh(COD)OH]2 gave a mixture of unreacted imine 1 (36%) and racemic addition product 3
15
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
(59%), while treatment in the presence of [Rh(C2H4)2Cl]2 and 4a yielded enantiomerically pure
product 3 in 99% with >99% ee at quantitative conversion (Entries 1, 2). For comparison with
toluene-based microemulsions, the homogeneous catalysis was also performed in toluene[37b]
1
instead. H-NMR analysis of the crude product revealed a (90 : 10) mixture of product 3 and
alcohol 13, which was purified by chromatography to give 3 in 82% with high enantioselectivity
(99% ee) and 9% of 13 (10% ee) (Entry 3). The addition reactions with both ligands 4b (R =
OC6H13) and 4e (R = OH) proceeded cleanly (Entries 4, 7), whereas ligands 4c and 4d revealed
complex crude product mixtures of unreacted 1, addition product 3, and byproducts 13, 14 (see
1
Table 2) according to H-NMR analysis (Entries 5, 6), suggesting that the alkyne terminus
interfered with the desired 1,2-addition under the used basic conditions, resulting in hydrolysis of
imine 1 to aldehyde 14 and subsequent 1,2-addition to 13. After chromatography, amine 3 was
isolated in moderate yields with ee values of 91–93%.
In microemulsions consisting of C8G1 surfactant, toluene and water (see Figure 4) under
otherwise same conditions the 1,2-addition with benchmark catalyst [Rh(C2H4)2Cl]2/4a gave a
1
crude product mixture of starting material 1, addition product 3 and alcohol 13 according to H-
NMR monitoring, from which product 3 was isolated in high yield and enantiomeric excess
(93%, >99% ee) (Entry 8). Thus, in comparison to the homogeneous catalysis in toluene
(Entry 3), both the chemoselectivity, i.e. the ratio of amine 3 vs. alcohol 13, was shifted in favor
of 3 and the isolated yield was improved. The arylation in the presence of [Rh(C2H4)2Cl]2 with
chiral ligands 4b and 4e, respectively, provided results comparable to 4a albeit with lower yields
and ee values (Entries 9, 12). The largest difference between catalysis in conventional solvent
and microemulsion, however, was observed for diene ligands 4c, 4d with alkynyl terminus,
where a complete reversal of the chemoselectivity was detected, leading to alcohol 13 as the
major product (Entries 10, 11).
16
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
We then studied the catalytic properties of chiral oxazolidinone norbornadienes 5 and 6 in
both the confined system provided by the microemulsion and in conventional solution (Table 2).
Table 2. Comparison of 1,2-addition reactions in solution and microemulsion catalyzed
by a complex of Rh/ligand 5 and 6, respectively. The reaction progress was monitored by
1H-NMR.
Entry Ligand
dr
Solvent
NMR yield [%][a]
Yield [%][b]
ee [%]
3
1
3
14
8
3
61
69
n.d.
61
20
32
48
73
55
61
61
84
79
59
75
65
77
1
2
5a,5a' 82 : 18 dioxane traces
91
89
14
76
25
32
68
74
55
60
83
93
97
83
88
77
84
36 (S)
32 (R)
n.d.
5b,5b' 98 : 2
5b,5b' 98 : 2
dioxane
toluene
10
67
18
55
15
11
17
27
18
–
1
3
13
6
4
5b
5d
5d'
100 : 0 dioxane
100 : 0 dioxane
0 : 100 dioxane
90 (R)
94 (R)
56 (S)
74 (R)
94 (R)
98 (R)
92 (R)
90 (R)
22 (R)
92 (R)
12 (R)
70 (R)
96 (R)
90 (R)
5
20
53
20
9
6
7
6a,6a' 72 : 28 dioxane
6b,6b' 85 : 15 dioxane
8
9
6b
100 : 0 dioxane
18
22
17
7
10
11
12
13
14
15
16
17
6c,6c' 68 : 32 dioxane
5b,5b' 98 : 2
ME [c]
ME [d]
ME [d]
ME [d]
ME [c]
ME [c]
ME [c]
5b
5d
5d'
100 : 0
100 : 0
0 : 100
–
–
3
–
17
12
23
16
6a,6a' 72 : 28
6b 100 : 0
6c,6c' 68 : 32
–
–
–
[a] Mesitylene was used as the internal standard.[53] [b] Isolated yield. [c] ME: 0.60 g
C8G1, 0.89 mL toluene, 0.77 mL H2O at γ = 0.26 and α = 0.54. [d] ME: 0.60 g C8G1,
0.81 mL toluene, 0.70 mL H2O at γ = 0.28 and α = 0.54.
Under the used conditions in solution in the presence of methyl Evans diene 5a,5a' (dr 82 : 18)
product 3 was isolated from a crude mixture of 3 and aldehyde 14 in 61%, but a reversed enantio-
17
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
1
selectivity (36% ee (S)) was observed (Entry 1). H-NMR monitoring of the reaction using
phenyl Evans diene 5b,5b' (dr 98 : 2) as ligand in dioxane showed a (10:89:1) crude product
mixture of 1 : 3 : 14, whereas the arylation in toluene was significantly retarded resulting in a
crude mixture which was dominated by starting imine 1 (67%) (Entries 2, 3). However, single
diastereomer 5b in dioxane yielded after workup amine 3 in 61% with 90% ee (R) (Entry 4). The
single diastereomers 5d and 5d' with 4-chlorophenyl substituent, respectively, were studied in
parallel experiments in dioxane (Entries 5, 6). In both cases, incomplete conversion and large
amounts of aldehyde 14 were detected, providing the addition product 3 in low yields of 20% and
32%, respectively. However, ligand-controlled enantioselectivity was observed with diastereomer
5d producing a matched case (94% ee (R)) (Entry 5), while diastereomer 5d' gave the
mismatched case (56% ee (S)) with opposite configuration of the major enantiomer of 3
1
(Entry 6). Incomplete conversions in conventional solution were monitored by H-NMR for all
SuperQuat dienes 6 irrespective of their diastereomeric ratios and the substituent. Amine 3 was
isolated in moderate yields (48–73%) but high enantiomeric excesses of 92–98% ee (R) with
exception of ligand mixture 6a,6a' (74% ee (R)) (Entries 7–10).
However, the 1,2-additions of boroxine 2 to tosylimine 1 in confinement in the presence of in
situ generated catalyst from [Rh(C2H4)2Cl]2 and chiral norbornadiene ligands 5 and 6,
respectively, clearly differed from those in solution. The catalysis in microemulsion went to
completion with target amine 3 as the major product. No starting material 1 could be detected in
the crude product but small amounts of byproduct 14 (Table 2). In microemulsion (see Figure 4)
and 0.02 M KOH phenyl Evans diene 5b,5b' (dr 98 : 2) provided amine 3 in 61% yield but
significantly improved enantioselectivity (90% ee (R)) as compared to the reaction in dioxane
(Entries 2, 11). In microemulsion using single diastereomer 5b the yield of 3 was further
increased to 84%, but the enantioselectivity was markedly reduced to only 22% ee (Entry 12).
18
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
The beneficial effect of the microemulsion on the Rh-catalyzed 1,2-addition was most
prominently demonstrated for diastereomerically pure 4-chlorophenyl Evans diene 5d, which
strongly favored the formation of amine 3 (97% crude, 79% isolated, 92% ee (R)) with a matched
enantioselectivity (Entry 13). The diastereomerically pure ligand 5d' also afforded addition
product 3 in much higher yield than in the conventional dioxane solution, albeit with a
mismatched enantiocontrol (59%, 12% ee (R)) (Entry 14). As compared to the catalyses in the
conventional solution dioxane, SuperQuat dienes 6a,6a', 6b and 6c,6c', respectively, tend to
increase the yield of product 3 in microemulsions, the enantioselectivities, however, retained
(Entries 15–17). The more pronounced rate enhancement observed for Evans diene 5b in
microemulsion vs. dioxane (Entries 4, 12) as compared to SuperQuat diene 6b (Entries 9, 16)
might be due to different coordination modes of the Rh catalyst (Figure 1). However, based on
the current results it is too early to draw further mechanistic conclusion.
Kinetic studies of Rh-catalyzed asymmetric 1,2-additions: The kinetics of the Rh-catalyzed
arylation of N-tosylimine 1 with triphenylboroxine 2 was monitored by 1H-NMR with mesitylene
as internal standard. Figure 6 shows the yield obtained at T = 60°C in the different reaction
media, i.e. dioxane, toluene and the microemulsion as a function of time. In agreement with
previous work in the literature temperatures 60 °C are required to promote transmetalla-
tion.[30,35b] While in the reaction profiles shown in Figure 6a the Rh-catalyst with ligand 4a was
used, the Rh-catalyst with ligand 5b was applied in the profiles of Figure 6b. Considering at first
the profiles monitored for the Rh/ligand 4a system, it can be seen that in dioxane (>99%) and the
microemulsion (>96%) an almost complete conversion was detected at t = 4 min. However, in
toluene, which shows similar kinetics, only a yield of 90 wt% was found after 4 minutes and
remained constant for 24 hours. A first order kinetics with respect to N-tosylimine 1 was
19
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
observed in all experiments. Accordingly, the kinetic data were described by a mono-exponential
fit obtained via integration of the first order rate equation
⁄
푑[푝푟표푑푢푐푡 ퟑ] 푑푡 = 푘app[푁-tosylimine ퟏ]
yielding the reciprocal rate constant kapp Thereby, we estimated the systematic error with
respect to time to be of the order of 20 s (tstart7 s: time needed to obtain a homogeneous
distribution after the addition of the reactant molecules; tend13 s: time needed to remove the
catalyst/ligand complex by filtration to stop the reaction). The values of (together with the
standard deviation for  > 1 min) and the maximum yield obtained for reactions with the Rh-
catalyst/ligand 4a and ligand 5b complexes in the different reaction media are compiled in
Table 3.
Using the Rh-catalyst/ligand 4a system, the 1,2-addition proceeded fast in all three reaction
media. Although a systematic trend in the initial rate might be deducible from the first data point,
we decided to estimate the value of the reciprocal rate constant  only qualitatively due to the
systematic time error of the order of 20 s and the fact that only one data point (yield after two
minutes) could be recorded between the start of the reaction and complete conversion. Instead we
only indicated the reciprocal rate constant to be smaller than 1 min for all three reaction media.
However, using the Rh/ligand 5b system in the microemulsion a yield of 93% was reached after 8
minutes, whereas in dioxane a maximum yield of 76% was only detected after 128 minutes and
remained constant. In toluene, only a maximum yield of 4% was observed after 24 hours. The
increase of the reciprocal rate constant (Table 3), unambiguously showed that the microemulsion
reaction medium provided not only an almost complete conversion, but also an almost one order
of magnitude faster reaction rate than dioxane.
20
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
Figure 6. Yield of the rhodium-catalyzed 1,2-addition of triphenylboroxine 2 to N-tosylimine 1
conducted at 60°C as a function of time using different reaction media. While the kinetics
obtained for the Rh/ligand 4a system (a) proceeded so fast in all reaction media, that only one
data point could be recorded between the start of the reaction and complete conversion
(reciprocal rate constant of < 1 min), for the Rh/ligand 5b system (b) the microemulsion
provides not only a higher conversion, but also almost one order of magnitude faster reaction rate
than dioxane. The data were described by a mono-exponential fit providing the reciprocal rate
constant  (together with the standard deviation) and the maximum yield (Table 3).
Table 3. Reciprocal rate constant and maximum yield of the Rh-
catalyzed 1,2-addition of triphenylboroxine 2 to N-tosylimine 1 at
60°C in different reaction media and two different Rh/ligand
systems (4a and 5b).
Entry
Medium
dioxane
toluene
ME[b]
Ligand
4a
 [min]
< 1.0
NMR yield [%][a]
1
2
3
4
5
6
>99
90
96
76
4
4a
< 1.0
4a
< 1.0
dioxane
toluene
ME[b]
5b
9.1 ± 0.7
11.9 ± 3.0
< 1.0
5b
5b
93
[a] Mesitylene was used as the internal standard. [b] ME: 0.60 g
C8G1, 0.89 mL toluene, 0.77 mL H2O at γ = 0.26 and α = 0.54.
21
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
In the next step, the influence of the temperature on the kinetics of the Rh/ligand 4a-catalyzed
1,2-addition of 2 to tosylimine 1 was studied using dioxane and the microemulsion as reaction
media.
Figure 7. Yield of the 1,2-addition of 2 to N-tosylimine 1 in the presence of chiral ligand 4a as a
function of time adjusting different temperatures. (a) In dioxane the reaction proceeded slow at
low temperatures. (b) In the microemulsion fast kinetics were also observed at T = 30°C, which
were a factor 4 faster than in dioxane at the same temperature. The data were described by a
mono-exponential fit providing the reciprocal rate constant  and the maximum yield (Table 4).
Figure 7a shows that in dioxane the kinetics of the addition exhibits a strong temperature
dependence. The reciprocal rate constant  was found to decrease from  11.9 min at 30°C (the
maximum yield of 98% was reached only after 128 min) to < 1 min at 60°C, i.e. showing that
the reaction proceeds slowly at low temperatures. On the other hand, the reaction profiles shown
in Figure 7b demonstrate that the Rh-catalyzed addition reaction in the microemulsion proceeds
fast also at T = 30°C, i.e. a complete conversion was detected at t = 16 min. The reciprocal rate
constant  and the maximum yield of the reaction profiles are compiled in Table 4.
22
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
Table 4. Reciprocal rate constants and maximum yield of the
Rh/4a-catalyzed addition of 2 to N-tosylimine 1 at different tempe-
ratures in dioxane and the microemulsion.
Entry
Medium
dioxane
dioxane
dioxane
dioxane
ME[b]
T [°C]
25
 [min]
NMR yield [%][a]
1
2
3
4
5
6
19.2 ± 1.3
95
30
11.8 ± 1.4 >99
9.8 ± 0.3 >99
40
60
< 1.0
>99
96
30
3.1 ± 0.6
< 1.0
ME[b]
60
96
[a] Mesitylene was used as the internal standard. [b] ME: 0.60 g
C8G1, 0.89 mL toluene, 0.77 mL H2O at γ = 0.26 and α = 0.54.
Conclusion
In order to study the influence of the reaction media, i.e. homogeneous versus nanostructured, on
asymmetric Rh-catalyzed nucleophilic additions of triphenylboroxine 2 to N-tosylimine 1 we
developed synthetic routes towards two series of novel chiral diene ligands based on C2-sym-
metrical enantiomerically pure 1,4-diarylbicyclo[3.3.0]octadienes 4a–e and diastereomerically
enriched and enantiomerically pure norbornadiene oxazolidinone ligands 5a–d, 6a–d carrying
either the Evans auxiliary (5a–d) or the SuperQuat auxiliary (6a–d). The diene ligands 4–6
differed in their polarity and ligands 5, 6 possessed an additional binding site for Rh, which led
for 5b to the formation of a mononuclear complex [RhCl(5b)]. While toluene and dioxane were
the homogeneous reaction media, a microemulsion was used as reaction medium providing not
only liquid confinement but also mediated the miscibility between polar and nonpolar reactants.
The aqueous domains of the microemulsion are a good solvent for KOH, needed to activate
catalyst/ligand system. The hydrophobic reactants N-tosylimine 1 and triphenylboroxine 2
dissolve well in the toluene domains, while the catalyst/ligand system, possessing both polar and
apolar parts, can reside in/at the amphiphilic surfactant film. Assuming that the bicontinuous
23
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
structure allows for the easiest access of the catalyst/ligand system with respect to both KOH and
the reactants, we aimed for a microemulsion containing equal amounts of water and oil (i.e.
hydrophobic phase). Starting from the well-known microemulsion system of the type H2O–
cyclohexane–pentaethylene glycol monohexyl ether (C6E5), cyclohexane was replaced with the
more polar toluene. In order to compensate for the shift of the phase boundaries to lower
temperature, the surfactant C6E5 was partially replaced by the hydrophilic surfactant n-octyl β-ᴅ-
glucopyranoside C8G1.
The influence of KOH, catalyst and ligands as well as reactants on the phase behaviour was
examined to find the optimal toluene-microemulsion as reaction medium. While the presence of
the Rh diene catalysts as well as KOH (low concentration) of had almost no influence on the
phase boundaries, N-tosylimine 1 and particularly triphenylboroxine 2 showed a strong influence.
Using the pendant drop technique, we found that the addition of 2 decreased the water/toluene
interfacial tension from 36 mNm–1 to 12 mNm–1. This somewhat unexpected effect points to the
formation of hydrolysis products as e.g. boronic acid, which rather act as hydrophobic co-
surfactants and thus not only decrease the water/toluene interfacial tension but also change the
curvature of the amphiphilic film and thus the phase behaviour of the microemulsion system.
This effect was compensated replacing the remaining surfactant C6E5 with the hydrophilic C8G1
to give the reaction microemulsion H2O/KOH–toluene/N-tosylimine 1/triphenylboroxine 2–C8G1.
The length scale of the liquid confinement was determined via SAXS, showing a domain size of
the aqueous and toluene/N-tosylimine 1/triphenylboroxine 2 compartments of 55 Å. Considering
that the concentration of the catalyst/ligand complex with respect to reactant 1 is 2.5 mol%, on
average every second toluene domain contains a catalyst/ligand complex.
The catalyses were strongly dependent on both ligand type and reaction medium. For 1,4-
diarylbicyclo[3.3.0]octadienes 4 good yields (up to 87%) and enantioselectivities (>95% ee) of
24
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
the addition products 3 were obtained irrespective of the polarity of ligand 4 and reaction medium
(microemulsion vs dioxane or toluene). The exception were alkyne-terminated ligands 4c,d,
which provided moderate yields (≤ 61%), but high enantioselectivities (up to 93% ee) of 3 and
considerable amounts (up to 30%) of racemic secondary alcohol 13 in dioxane, whereas the
microemulsion led to preferred formation of the alcohol 13 (up to 74%) at the expense of amines
3 (up to 32%).
When employing norbornadiene oxazolidinones 5, 6 catalytic reactions were more sluggishly
in dioxane and almost ceased in toluene. Yields and ee values showed considerable variations
depending on the substitution pattern of the ligands 5, 6. In contrast, when the reactions were
performed in microemulsions, yields (up to 97%) and enantioselectivities (up to 96% ee) in-
creased in most cases. The most pronounced effect of the microemulsions was observed for
diastereomerically pure ligands 5d, 5d’, which led to improved yields and matched/mismatched
selectivities. While the preferred configurations of the matched cases were similar for micro-
emulsions and dioxane (92% ee (R) and 94% ee (R) for 5d), the mismatched cases gave opposite
configurations in microemulsions and dioxane (12% ee (R) and 56% ee (S) for 5d’).
The observed rate enhancement of the catalytic reaction by the microemulsion, in particular
for ligand 5b which is less active in dioxane solution as compared to ligands 4 could also be
clearly confirmed by kinetic studies, which showed that at T = 60°C the reaction rate in the
microemulsion is almost one order of magnitude faster than in dioxane and more than one order
of magnitude faster than in toluene, where a yield of only 4% was obtained. Furthermore,
performing the 1,2-addition with Rh/ligand 4a catalyst at T = 30°C, the reaction in micro-
emulsion was 4 times faster than in dioxane.
In conclusion, we have shown for the nucleophilic addition of phenylboroxine 2 to N-tosyl-
imine 1 catalyzed by chiral Rh-diene complexes that the liquid confinement provided by micro-
25
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
emulsions can improve both reaction rate and enantioselectivity. These experiments will extend
the practical use of microemulsions as organized reaction media for other asymmetric catalyses.
Acknowledgements
Generous financial support by the Deutsche Forschungsgemeinschaft (DFG – project number
358283883 –SFB 1333, subprojects A7, B3, and large instrumentation grant INST 41/897-1
FUGG), the Ministerium für Wissenschaft, Forschung und Kunst des Landes Baden-Württem-
berg, the European Commission (ERASMUS fellowship for A.S.) and the Fonds der Chemischen
Industrie is gratefully acknowledged. Furthermore, Yaseen Qawasmi is grateful to the Konrad
Adenauer Stiftung for the financial support. The authors thank Carsten Müller for his help with
the SAXS measurements.
Conflict of interest
The authors declare no conflict of interest.
Keywords: asymmetric catalysis  C–C coupling  diene ligands  kinetics  sugar surfactants
References
[1] M. Kahlweit, R. Strey, Angew. Chem. Int. Ed. Engl. 1985, 24, 654–668; Angew. Chem.
1985, 97, 655–659.
[2] a) T. Sottmann, R. Strey, Fundamentals of Interface and Colloid Science: Microemulsions,
Vol. 5 (Ed.: J. Lyklema), 2005, pp. 5.1–5.96; b) R. Strey, Colloid Polym Sci 1994, 272,
1005–1019.
[3] T. Sottmann, R. Strey, S.-H. Chen, J. Chem. Phys. 1997, 106, 6483–6491.
[4] a) K. Holmberg, Curr. Opin. Colloid Interface Sci. 2003, 8, 187–196; b) T. Wielpütz, T.
Sottmann, R. Strey, F. Schmidt, A. Berkessel, Chem. Eur. J. 2006, 12, 7565–7575.
[5] a) S. Serrano-Luginbühl, K. Ruiz-Mirazo, R. Ostaszewski, F. Gallou, P. Walde, Nat. Rev.
Chem. 2018, 2, 306–327; b) G. La Sorella, G. Strukul, A. Scarso, Green Chem. 2015, 17,
26
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
644–683; c) I. Rico-Lattes, E. Perez, S. Franceschi-Messant, A. Lattes, C. R. Chimie 2011,
14, 700–715.
[6] a) M. Schwarze, T. Pogrzeba, I. Volovych, R. Schomäcker, Catal. Sci. Technol. 2015, 5,
24–33; b) M.-J. Schwuger, K. Stickdorn, R. Schomaecker, Chem. Rev. 1995, 95, 849–864.
[7] M. Schwarze, T. Pogrzeba, K. Seifert, T. Hamerla, R. Schomäcker, Catal. Today 2015,
247, 55–63.
[8] J. S. Milano-Brusco, H. Nowothnick, M. Schwarze, R. Schomäcker, Ind. Eng. Chem. Res.
2010, 49, 1098–1104.
[9] a) H. H. Y. Ünveren, R. Schomäcker, Catal. Lett. 2005, 102, 83–89; b) H. H. Y. Ünveren,
R. Schomäcker, Catal. Lett. 2006, 110, 195–201; c) M. Haumann, H. Koch, P. Hugo, R.
Schomäcker, Appl. Catal., A 2002, 225, 239–249; d) M. Haumann, H. Yildiz, H. Koch, R.
Schomäcker, Appl. Catal., A 2002, 236, 173–178.
[10] A. Rost, Y. Brunsch, A. Behr, R. Schomäcker, Chem. Eng. Technol. 2014, 37, 1055–1064.
[11] T. Yosef, R. Schomäcker, M. Schwarze, M. Fanun, F. Gelman, J. Blum, J. Mol. Catal. A:
Chem. 2011, 351, 46–51.
[12] Z. Nairoukh, M. Fanun, M. Schwarze, R. Schomäcker, J. Blum, J. Mol. Catal. A: Chem.
2014, 382, 93–98.
[13] H. N. Kagalwala, D. N. Chirdon, I. N. Mills, N. Budwal, S. Bernhard, Inorg. Chem. 2017,
56, 10162–10171.
[14] a) M. Moniruzzaman, M. Goto, Methods Mol. Biol. (Clifton, N.J.) 2011, 743, 37–49; b) M.
Moniruzzaman, N. Kamiya, M. Goto, Org. Biomol. Chem. 2010, 8, 2887–2899.
[15] a) M. Laupheimer, S. Engelskirchen, K. Tauber, W. Kroutil, C. Stubenrauch, Tenside,
Surfactants, Deterg. 2011, 48, 28–33; b) M. Sathishkumar, R. Jayabalan, S. P. Mun, S. E.
Yun, Bioresour. Technol. 2010, 101, 7834–7840; c) C. Chiappe, E. Leandri, B. D.
Hammock, C. Morisseau, Green Chem. 2007, 9, 162–168; d) S. Backlund, F. Eriksson, G.
Hedstrm, A. Laine, M. Rantala, Colloid. Polym. Sci. 1996, 274, 540–547; e) P. Cesar
deJesus, P. Luiz Ferreirada Silva, J. JuarezJoão, M. da GraçaNascimento, Synth. Commun.
1998, 28, 2893–2901; f) L. Giorno, N. Li, E. Drioli, Biotechnol. Bioeng. 2003, 84, 677–
685; g) G. Hedström, M. Backlund, J. P. Slotte, Biotechnol. Bioeng. 1993, 42, 618–624; h)
K. M. Lee, D. Martina, C. U. Park, J.-F. Biellmann, Bull. Korean Chem. Soc. 1990, 11,
472–473; i) G. P. Rai, S. Sakai, A. M. Flórez, L. Mogollon, L. P. Hager, Adv. Synth. Catal.
2001, 343, 638–645; j) G. D. Rees, K. Carlile, G. E. Crooks, T. R.-J. Jenta, L. A. Price, B.
27
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
H. Robinson in Engineering of/with Lipases (Ed.: F. X. Malcata), Springer Netherlands,
Dordrecht, 1996, pp. 577–595; k) G. D. Rees, B. H. Robinson, G.R. Stephenson, Biochim.
Biophys. Acta 1995, 1259, 73–81; l) S.-F. Song, Y.-X. Luan, Chem. Res. Chin. Univ. 2010,
26, 110–113; m) S.-F. Song, Y.-X. Luan, F.-S. Lu, Chem. Res. Chin. Univ. 2007, 23, 749–
752; n) I. Uemasu, W. L. Hinze, Chirality 1994, 6, 649–653; o) J. Moreno, A. Samoza, C.
del Campo, E. F. Llama, J. Sinisterra, J. Mol. Catal. A: Chem. 1995, 95, 179–192.
[16] a) B. Nuthakki, J. M. Bobbitt, J. F. Rusling, Langmuir 2006, 22, 5289–5293; b) M.
Schmidt, C. Urban, S. Schmidt, R. Schomäcker, ACS Omega 2018, 3, 13355–13364.
[17] S. Handa, D. J. Lippincott, D. H. Aue, B. H. Lipshutz, Angew. Chem. Int. Ed. 2014, 53,
10658–10662; Angew. Chem. 2014, 126, 10834–10838.
[18] a) C. Defieber, H. Grützmacher, E. M. Carreira, Angew. Chem. Int. Ed. 2008, 47, 4482–
4502; Angew. Chem. 2008, 120, 4558–4579; b) J. B. Johnson, T. Rovis, Angew. Chem. Int.
Ed. 2008, 47, 840–871; Angew. Chem. 2008, 120, 852–884; c) R. M. Maksymowicz, A. J.
Bissette, S. P. Fletcher, Chem. Eur. J. 2015, 21, 5668–5678; d) D. Müller, A. Alexakis,
Chem. Commun. 2012, 48, 12037–12049; e) M. Nagamoto, T. Nishimura, ACS Catal.
2017, 7, 833–847.
[19] T. Hayashi, K. Ueyama, N. Tokunaga, K. Yoshida, J. Am. Chem. Soc. 2003, 125, 11508–
11509.
[20] C. Fischer, C. Defieber, T. Suzuki, E. M. Carreira, J. Am. Chem. Soc. 2004, 126, 1628–
1629.
[21] P. Maire, S. Deblon, F. Breher, J. Geier, C. Böhler, H. Rüegger, H. Schönberg, H.
Grützmacher, Chem. Eur. J. 2004, 10, 4198–4205.
[22] a) G. Berthon-Gelloz, T. Hayashi, J. Org. Chem. 2006, 71, 8957–8960; b) C. Defieber, J.-F.
Paquin, S. Serna, E. M. Carreira, Org. Lett. 2004, 6, 3873–3876; c) C.-G. Feng, M.-H. Xu,
G.-Q. Lin, Synlett 2011, 1345–1356; d) T. Gendrineau, O. Chuzel, H. Eijsberg, J.-P. Genet,
S. Darses, Angew. Chem. Int. Ed. 2008, 47, 7669–7672; Angew. Chem. 2008, 120, 7783–
7786; e) S. Helbig, K. V. Axenov, S. Tussetschläger, W. Frey, S. Laschat, Tetrahedron
Lett. 2012, 53, 3506–3509; f) C.-C. Liu, D. Janmanchi, C.-C. Chen, H.-L. Wu, Eur. J. Org.
Chem. 2012, 2503–2507; g) Y. Luo, A. J. Carnell, Angew. Chem. Int. Ed. 2010, 49, 2750–
2754; Angew. Chem. 2010, 122, 2810–2814; h) M. Mayr, C. J. R. Bataille, S. Gosiewska, J.
A. Raskatov, J. M. Brown, Tetrahedron: Asymmetry 2008, 19, 1328–1332; i) K. Okamoto,
T. Hayashi, V. H. Rawal, Org. Lett. 2008, 10, 4387–4389; j) Y. Otomaru, K. Okamoto, R.
28
This article is protected by copyright. All rights reserved.

10.1002/chem.201900947
Chemistry - A European Journal
Shintani, T. Hayashi, J. Org. Chem. 2005, 70, 2503–2508; k) Y. Otomaru, N. Tokunaga, R.
Shintani, T. Hayashi, Org. Lett. 2005, 7, 307–310; l) T. Pecchioli, M. Christmann, Org.
Lett. 2018, 20, 5256–5259; m) R. Shintani, Y. Ichikawa, K. Takatsu, F.-X. Chen, T.
Hayashi, J. Org. Chem. 2009, 74, 869–873; n) M.-C. Melcher, B. Rolim Alves da Silva, T.
Ivšić, D. Strand, ACS Omega 2018, 3, 3622–363.
[23] a) T. Mühlhäuser, A. Savin, W. Frey, A. Baro, A. J. Schneider, H.-G. Döteberg, F. Bauer,
A. Köhn, S. Laschat, J. Org. Chem. 2017, 82, 13468–13480; b) S. Helbig, S. Sauer, N.
Cramer, S. Laschat, A. Baro, W. Frey, Adv. Synth. Catal. 2007, 349, 2331–2337.
[24] a) X. Hu, M. Zhuang, Z. Cao, H. Du, Org. Lett. 2009, 11, 4744–4747; b) Y. Wang, X. Hu,
H. Du, Org. Lett. 2010, 12, 5482–5485.
[25] B. M. Trost, A. C. Burns, T. Tautz, Org. Lett. 2011, 13, 4566–4569.
[26] a) A. Kina, K. Ueyama, T. Hayashi, Org. Lett. 2005, 7, 5889–5892; b) F. Läng, F. Breher,
D. Stein, H. Grützmacher, Organometallics 2005, 24, 2997–3007; c) M.-C. Melcher, T.
Ivšić, C. Olagnon, C. Tenten, A. Lützen, D. Strand, Chem. Eur. J. 2018, 24, 2344–2348.
[27] a) C.-C. Chen, B. Gopula, J.-F. Syu, J.-H. Pan, T.-S. Kuo, P.-Y. Wu, J. P. Henschke, H.-L.
Wu, J. Org. Chem. 2014, 79, 8077–8085; b) X. Dou, Y. Lu, T. Hayashi, Angew. Chem. Int.
Ed. 2016, 55, 6739–6743; Angew. Chem. 2016, 128, 6851–6855; c) Y. Luo, H. B. Hepburn,
N. Chotsaeng, H. W. Lam, Angew. Chem. Int. Ed. 2012, 51, 8309–8313; Angew. Chem.
2012, 124, 8434–8438; d) T. Nishimura, T. Nagai, R. Takechi, Y. Ebe, Synthesis 2016, 48,
2612–2618; e) C.-Y. Wu, Y.-N. Yu, M.-H. Xu, Org. Lett. 2017, 19, 384–387; f) B. Zhou,
C. Ming So, Y. Lu, T. Hayashi, Org. Chem. Front. 2015, 2, 127–132.
[28] R. Li, Z. Wen, N. Wu, Org. Biomol. Chem. 2016, 14, 11080–11084.
[29] T. Yasukawa, T. Kuremoto, H. Miyamura, S. Kobayashi, Org. Lett. 2016, 18, 2716–2718.
[30] T. Hayashi, K. Yamasaki, Chem. Rev. 2003, 103, 2829–2844.
[31] M. Hatano, T. Nishimura, Angew. Chem. Int. Ed. 2015, 54, 10949–10952; Angew. Chem.
2015, 127, 11099–11102.
[32] a) T. Nishimura, Y. Yasuhara, T. Hayashi, J. Am. Chem. Soc. 2007, 129, 7506–7507; b) R.
Shintani, Y. Sannohe, T. Tsuji, T. Hayashi, Angew. Chem. Int. Ed. 2007, 46, 7277–7280;
Angew. Chem. 2007, 119, 7415–7418.
[33] a) K. Aikawa, Y. Takabayashi, S. Kawauchi, K. Mikami, Chem. Commun. 2008, 5095–
5097; b) Y. Liu, H. Du, J. Am. Chem. Soc. 2013, 135, 6810–6813; c) T. Punniyamurthy, M.
29
This article is protected by copyright. All rights reserved.