Modular Synthesis of Chiral NHC Precursors and Their Silver and Gold Complexes

Article abstract of DOI:10.1021/acs.organomet.0c00530

The stereoselective synthesis of chiral heterocyclic carbene precursors and the structural features of their silver and gold complexes were investigated. The prepared compounds are all based on the imidazolidine scaffold and bear the bulky tert-butyl subs

Full text of DOI:10.1021/acs.organomet.0c00530

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Modular Synthesis of Chiral NHC Precursors and Their Silver and
Gold Complexes
́
́
Zita Szabo, Matyas Timari, Rudolf Kassai, Bianka Szokol, Attila C. Benyei, Tamas Gati, Attila Paczal,*
and Andras Kotschy*
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ABSTRACT: The stereoselective synthesis of chiral heterocyclic
carbene precursors and the structural features of their silver and gold
complexes were investigated. The prepared compounds are all based
on the imidazolidine scaffold and bear the bulky tert-butyl
substituent on the backbone in a stereocontrolled manner. The
majority of the synthesized carbene precursors carry an additional
element of central chirality in the side chain, and for some of them
on formation of their silver or gold complexes a third element of
asymmetry, axial chirality through hindered rotation of the aromatic substituent, is also present. The systematic study of the
stereoselective formation of the NHC precursors led to scalable routes without the need for chiral chromatography. The NHC
precursors were transformed efficiently into their silver and gold complexes, whose structural features were studied in detail both in
solution and in the solid phase.
INTRODUCTION
■
The first isolation of a free N-heterocyclic carbene (NHC) by
Arduengo1 initiated a rapid development of this field.2 This
was fueled by the easily tunable electronic and steric properties
of NHC ligands through structural modifications and the
strength of the NHC−metal bond resulting in stable
complexes. In addition to the utility of their metal complexes
in catalysis, these carbenes have found widespread use in
organocatalysis3 and in materials science;4 for some of their
transition-metal complexes antibacterial and anticancer effects
have also been reported.5
The increasing prominence of asymmetric transformations
led to the development of chiral NHC precursors and their
metal complexes. Several enantioselective transformations were
reported employing C2-symmetrical NHCs.6 The research into
C1-symmetrical NHCs has also developed dynamically in
recent years due to reports of an improved control of
stereoselectivity over C2-symmetrical analogues in several
Figure 1. Representative examples of C2- and C1-symmetrical chiral
NHC precursors and our target NHC carbene complex structures
transformations.7 The majority of the C1-symmetrical NHC
precursors reported to date possess a dihydroimidazole core
with symmetrical C4 and C5 substituents and different
substituents on the two nitrogen atoms of the carbene center
(Figure 1). Alternatively, the symmetry of the central core can
be broken through cyclization, resulting in a bi- or polycyclic
carbene core. The number of examples with a nonsymmetrical
monocyclic core (i.e., thiazole, triazole)8 is more limited, and
only a few examples of imidazolium9 or dihydroimidazolium10
salts, having different substituents at C4 and C5, have been
reported.
(bottom right).
Received: August 6, 2020
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Scheme 1. Synthesis of the Key Intermediates 5a−c
Scheme 2. Synthesis of NHC Precursors 9a−h Using Amines as Diversity Sources
In NHCs bearing the stereodirecting group in the backbone,
the chiral information is typically remote from the catalytically
active metal center. The transfer of chirality can further be
complicated by freely rotating N substituents, resulting in poor
enantioselectivities. In the more successful examples this
difficulty is countered by the fact that the generation of the
NHC complex generates axial chirality at a hitherto freely
rotating substituent, which is in the proximity of the
catalytically active site, as first reported for C2-symmetrical
NHC complexes by Grubbs and co-workers (Figure 1).11
This concept was successfully extended to C1-symmetrical
NHCs having a symmetrical12 or asymmetrical backbone
substitution13 (Figure 1). In a recent example achiral NHC
precursors were transformed into chiral NHC-copper com-
plexes, the asymmetry being generated on complex formation
through hindered rotation, and the enantiomers could be
separated by chiral chromatography.14
In asymmetric transformations optimization of the con-
stitution of the NHC and, in case axial chirality is generated on
complex formation, its conformational properties are equally
important. This implies that the development of modular and
scalable synthetic routes to chiral NHCs are a prerequisite of
catalyst development.15 Understanding the interplay of
inherent backbone and side-chain chirality of NHCs and the
way axial chirality emerges during complex formation is
important to arrive at efficient enantioselective catalysts. With
these principles in mind, we set out to develop a synthetic
route that is applicable to a diverse set of NHC precursors
starting from easily accessible reagents, is easy to execute, and
is scalable. In addition to preparing chiral NHC precursors, we
also wanted to synthesize the corresponding NHC-silver and
NHC-gold complexes to study their structure and dynamic
behavior.
derived from a nonsymmetrical tert-butyl substitution. All
NHCs carried a chiral side chain, and to ensure the stability of
the NHC complexes, all molecules carried a bulky aromatic
substituent. In certain cases, this aromatic substituent was such
that it could be a source of axial chirality on complex
formation.
RESULTS AND DISCUSSION
■
Our synthetic approach relied on the synthesis of the
appropriately substituted ethylenediamine derivative followed
by ring closure with a C1 synthon. The first key intermediate
we wanted to prepare was the aminoaldehyde 5, which already
incorporated the tert-butyl group and the bulky aromatic
substituent on the nitrogen atom (Scheme 1). We first
synthesized the racemic aldehyde 5a in four steps. The reaction
of glyoxal acid ethyl ester (1) and diisopropylaniline in the
presence of a catalytic amount of formic acid at ambient
temperature showed complete conversion after 3 h. The
resulting Schiff base 2 was purified by column chromatography
to give a honey-like liquid, which was reacted with tBuMgCl in
anhydrous THF at 0 °C. The formed racemic amino ester
mixture 3 was converted to amino alcohol 4a by reduction
with LiAlH4 in THF. The enantiomers 4b,c could be separated
at this stage by chiral chromatography. Both the racemic amino
alcohol 4a and also the pure compounds 4b,c were oxidized to
the desired aminoaldehyde at 0 °C with Dess−Martin
periodinane. We noted that it was important to add 1.1
equiv of water for an improved reaction profile and higher
yield. After complete conversion the products 5a−c were
isolated by a simple workup without chromatography.
The second stage of the process was the generation of the
appropriate NHC precursors. With the homochiral amino-
aldehyde 5b or 5c as the starting material, a set of diamines
(8a−l) were prepared, the synthetic route depending on the
nature of the substituent. The first approach relied on the
introduction of diversity by the appropriate amine reagents
The general structure of the targeted NHC complexes is
shown in Figure 1. All target molecules are based on the
imidazolidine framework, with backbone chirality being
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Scheme 3. Synthesis of NHC Precursors 14a−d through the Diversification of Diamine 11
using reductive amination (Scheme 2). 5c was reacted with the
corresponding amines 6a−h followed by the in situ reduction
of the formed Schiff bases using NaBH4 or LiAlH4. Although
the imines 7a−h could be isolated in the process, this did not
lead to improved overall yields. Amines 6a,b, 6c,d, and 6e,f
resulted in the diastereoisomeric product pairs 8a,b, 8c,d, and
Scheme 4. Synthesis of Enantiopure Diamines and NHC
Precursors Starting from Racemic Aminoaldehyde 5a
1
8e,f, respectively. Their H NMR spectra not only confirmed
their structure but also provided evidence that the stereo-
chemical integrity was not modified during the preparation.
The concluding step of this sequence was the ring closure of
the diamines to give carbene precursors 9a−h. Using triethyl
orthoformate as the solvent and ammonium chloride as the
anion source we isolated the (4S)-4-tert-butyldihydroimidazo-
lium salts in good yield.
The next synthesis route was inspired by the fact that not all
amines are commercially available in optically pure form
(Scheme 3). We produced the enantiomerically pure diamine
11 in two steps from aldehyde 5b. The condensation of 5b
with 4-methoxybenzylamine, followed by reduction with
sodium borohydride, gave the PMB-protected diamine 10.
Removal of the PMB group by hydrogenolysis afforded the free
diamine 11, which was reacted with nonsymmetrical ketones
12a,b following a reductive amination protocol. The
diastereomeric pairs thus obtained could be separated by
normal phase chromatography to give enantiopure diamines
13a−d. The synthetic sequence was completed by the
imidazolidine ring closure using the previous conditions, and
we obtained the homochiral carbene precursors 14a−d.
The ease of separation of the diastereoisomeric diamines
13a−d prompted us to investigate briefly if the combination of
racemic aldehyde 5a with enantiomerically pure amines,
followed by normal-phase chromatographic separation, would
be an equally feasible approach to the homochiral diamines
(Scheme 4). 5a was reacted with commercially available
enantiomerically pure phenethylamine (6a) and 1-naphthyl-
amine (6c).
starting material. To test this hypothesis, we choose the L-
menthyl ester 17a, which was prepared from glyoxalic acid
(16) and L-menthol (15a) in a biphasic reaction in the
presence of a catalytic amount of H2SO4 (Scheme 5). After
separation of the two phases the oxoacetate 17a in diisopropyl
ether was reacted with diisopropylaniline in the presence of a
catalytic amount of formic acid at room temperature. The
resulting Schiff base 18a was purified by normal-phase column
chromatography. Then tBuMgCl in anhydrous THF was
added to the Schiff base at 0 °C. Under these reaction
conditions the diastereomer ratio obtained for 19a and 19c
was 3:7. The temperature dependence of the diastereomer
ratio was also investigated. Unfortunately, running the reaction
at −80 °C or at boiling temperature led to the same
diastereoisomer ratio as that at 0 °C.
From the diastereomer mixture we were able to isolate the
major component 19c by stirring the mixture overnight in 1.25
M ethanolic hydrochloric acid. Sequential recrystallizations
from hexane gave pure 19c as a white crystalline hydrochloric
acid salt. The NMR spectra of the obtained salt confirmed the
presence of a single diastereoisomer.
Compound 19c was converted to the desired amino alcohol
by reduction with LiAlH4. Since the crude product was
contaminated by menthol, it was purified as an HBF4 salt. After
filtration and setting of the pH to 7 the amino alcohol 4c was
obtained as a colorless oil. Enantiomerically pure 4c was
oxidized to aldehyde 5c at 0 °C with Dess−Martin periodinane
under the aforementioned conditions and was isolated in high
purity. An X-ray crystallography study of the gold complexes
The obtained diastereomeric mixtures (8a and 13e, 8c and
13f) were separated efficiently by normal-phase column
chromatography to give the appropriate enantiopure com-
pounds, with two of them, 8a,c, showing the same NMR
spectra and chromatographic properties as the previously
prepared batches. The ring closure of the new diamines 13e,f,
under standard conditions, gave the new carbene precursors
14e,f, respectively.
The weakness of the synthesis route described in Scheme 1
is the need for chiral chromatography. This could, in principle,
be avoided if we used a chiral ester of glyoxalic acid as the
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Scheme 5. Synthesis of the Enantiopure Aminoaldehydes 5b,c Using Menthol as Chiral Inducer
Scheme 6. Synthesis of NHC Precursors 9i and 14g
(see later) revealed that starting from L-menthol 4c and 5c
(compounds with S configuration at C4) are formed, while
when D-menthol was used, their enantiomers 4b and 5b
(compounds with R configuration at C4) are formed. The
mother liquor from the recrystallization of the different 19a−c
mixtures could also be reused by reduction of the ester and
separation of the enantiomers 4b and 4c by chiral
chromatography.
Although we were able to obtain 19c in an enantiopure
form, the observed asymmetric induction (7:3 ratio) during its
formation was suboptimal. To better understand the addition
step, we repeated it using the o-tert-butylaniline analogue 18c
(Scheme 6). The reaction of 18c and tBuMgCl yielded a
mixture of diastereomers (19e,f) in a 6:4 ratio that is inferior
even to the previous case. In contrast to 19a,c, diastereomers
19e,f could only be separated by normal-phase chromatog-
raphy. The pure diastereomers were converted to the amino
alcohols 4d,e in good yield by reduction with LiAlH4.
However, when the amino alcohol 4d was oxidized using the
standard conditions, we obtained a racemic aldehyde as the
product, probably due to stability problems. 5d was not
sufficiently stable for purification; therefore, the crude product
was carried on to the next reductive amination step.
Chromatographic purification yielded the two compounds 8i
and 13g, whose structure analysis confirmed that they were
diastereoisomers. After the usual ring-closure procedure we
obtained a pair of new, diastereomeric carbene precursors, 9i
and 14g.
Having obtained a diverse set of heterocyclic carbene
precursors, we converted them into their silver complexes.
Fourteen dihydroimidazolium salts (9a−i, 14a-d,g) were
treated with silver oxide in DCM at ambient temperature,
and the appropriate silver-NHC chloride complexes (20a−i,
21a−d,g) were isolated (Scheme 7). These complexes not only
are interesting in their own right but can also serve as the
source of other metal-NHC complexes through transmetala-
tion.
Exploiting this possibility, we treated the silver complexes
with gold(I) chloride dimethyl sulfide reagent to yield the
corresponding gold(I)-carbene chloride complexes 22a−i,
23a−d,g. The structures of the formed late-transition-metal-
NHC complexes was characterized both by NMR spectroscopy
and X-ray crystallography.
The NMR spectra of the silver complexes 20a−h and 21a−e
agreed well with their structures. The complex formation led to
a restricted conformational freedom of the benzene ring
attached to N3, which was evident from the NMR spectra.
Despite the presence of a symmetrically trisubstituted benzene
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3
Scheme 7. Transformation of the N-Heterocyclic Carbene
Precursors to NHC-Silver and NHC-Gold Complexes
and JCH ,Ag = 7.5 Hz) and two on the connecting carbon
2
atoms (3JC,Ag = 0.8 Hz and JCH(CH ),Ag = 2.1 Hz).
3
3
Unexpectedly, an additional JC,Ag = 1.4 Hz coupling was
observed on one of the methyls of the isopropyl groups. This
phenomenon cannot be explained by scalar coupling, since six
chemical bonds separate these atoms, but rather by a through-
space coupling, which suggests a very stable conformation of
the benzene ring stabilized by the two ortho-positioned
isopropyl groups.
In a study of the NMR spectra of the gold complex 22g two
sets of signals were observed in a 2:1 ratio, despite the fact that
this molecule has only one chiral carbon atom. Analogously to
the results of Dorta, who isolated and characterized chiral
NHC-Pd complexes starting from symmetrical ligands,16 this
indicates the hindered rotation between the asymmetrically
substituted benzene ring and the imidazolidine ring, generating
axial chirality in the molecule and resulting in a diastereomeric
mixture. In order to prove this, we registered a series of
temperature-dependent 1H NMR spectra in CD3CN. By
elevation of the temperature, the two signal sets collapsed
into one and we were able to determine the coalescence
temperature of this exchange process (Tcoalescence = 353 K,
Figure 2). On consideration of the initial signal split of the CH
Figure 2. Temperature-dependent 1H NMR spectra of 22g (aliphatic
section).
ring, a spin system with three diastereotopic aromatic
hydrogens was identified for the phenyl group. The different
chemical environment supports that there is a hindered
rotation around the bond connecting the benzene and
imidazolidine rings. Consequently, the two isopropyl groups
are also diasteretopic on the benzene ring: i.e., two CH and
signals at T = 273 K (31.5 Hz), an approximate 17.8 kcal/mol
free activation enthalpy can be calculated for the hindered
rotation.17
We observed the same behavior in the case of 22h, where
the two sets of signals appeared in the NMR spectra in a 3:1
ratio. We failed to determine the coalescence temperature of
this hindered rotation, since at the highest available temper-
ature with our cryo NMR probehead (T = 353 K) the two
signal sets still did not collapse into one, suggesting a much
higher free activation enthalpy for the hindered rotation of this
molecule. This observation is in line with the increased steric
bulk of the tert-butyl substituent in comparison to isopropyl.
For the diastereomeric mixture of 22h it was possible to
determine the axial chirality of the two components. By
selectively irradiating the two tert-butyl groups in a gradient-
selective 1D ROESY NMR experiment, we could unequiv-
ocally prove that the major signal set belongs to the
diasteroisomer where the two tert-butyl groups are on the
opposite side of the plane of the imidazolidine ring, whereas in
the minor diastereoisomer the two tert-butyl groups are on the
same side of the plane. In both compounds the tert-butyl group
on the imidazolidine ring shows steric proximity with the
1
four CH3 groups are visible in the H NMR spectrum.
Another interesting phenomenon was observed in the
DEPTQ NMR spectra of the NHC silver complexes. Silver
has two NMR-active spin 1/2 isotopes, 107Ag and 109Ag
(natural abundances 51.8% and 48.2%, respectively): i.e., in the
vicinity of the silver atom a doublet is expected on the 13C
signals as the silver couples with carbons. Two doublet signals
(JC,Ag = 240 Hz) were observed at 208.9 ppm corresponding to
the carbene carbon atom in the imidazolidine ring. The large
coupling constant is in line with the direct bonding between
the Ag and carbene atoms in the NHC-silver complex. The two
doublets can be explained by the isotope shift of the silver
atom: i.e., there is a small chemical shift difference
(δ(C−107Ag) − δ(C−109Ag) = 0.14 ppm) between the carbon
atoms connecting to 107Ag or 109Ag. In addition four additional
vicinal C−Ag couplings were detected in the DEPTQ
spectrum: two for the imidazolidine ring (3JCH,Ag = 8.2 Hz
E
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isopropyl moiety on the same side of the plane. In case of the
minor signal set, the tert-butyl group on the benzene ring
interacted with the same isopropyl group, whereas the major
component showed correlation with the isopropyl which is on
the opposite side of the plane (Figure 3).
molecules determined by NMR spectroscopy, we also
determined the X-ray structures of some complexes, including
22i.
Crystals suitable for X-ray structure determination were
grown of the NHC-gold complexes 22i and 23a,c,d,e. In case
of 23a there is also a solvent molecule (dichloromethane) in
the lattice. The determination of the absolute configuration of
the complexes was based on anomalous X-ray scattering and
was unambiguous. The Flack parameters18 in all cases are in
the range of 0.003−0.07, and the refinement did not prove the
presence of the other enantiomer.
The X-ray structure of 22i is in complete agreement with the
NMR measurements (Figure 4). The bulky tert-butyl
substituents on the imidazolidine ring and on the benzene
ring are on the opposite sides of the carbene ring’s plane, and
the chirality at the C4 position is also unambiguous. For the
diastereomeric complexes 23c,d the X-ray structures also
define the chirality at the benzylic position. For complexes 22i
and 23a,e the observed arrangement of substituents in the
benzylic position is in line with the chirality of the used
reagents.
The obtained X-ray structures resemble those of the known
NHC-gold(I) complexes. The C4−C5 distances also support
the C−C bond by lengths of 1.50−1.54 Å. The coordination
around the Au(I) is highly planar with the C−Au−Cl angle
being close to 180°. The Au−Cl distances are 2.27−2.28 Å,
while the Au−C distances are 1.976−2.03 Å. Further details of
the X-ray diffraction measurements can be found in the Tables
S1 and S2 in the Supporting Information.
Figure 3. Relevant NOE interactions in the diastereomers of 22h, 22i,
and 23g.
By analogy we could anticipate the appearance of axial
chirality through hindered rotation in case of the silver and
gold complexes 20i, 21g, 22i, and 23g. Of these complexes 22i
and 23g were investigated in detail. The NMR spectra
suggested the presence of a single diastereoisomer in both
cases. In the selective 1D ROE NMR experiment the tert-butyl
moiety had strong interaction with the NCH in the ring,
proving that in both molecules the two tert-butyl groups are
located on the opposite side of the plane of the imidazolidine
ring (Figure 3). To corroborate the axial chirality of these
CONCLUSIONS
■
In summary, we developed a scalable synthetic route to a new
class of C1-symmetrical chiral NHC precursors. The common
feature of these dihydroimidazolium salts is the presence of a
bulky tert-butyl substituent in the C4 position in a homochiral
form and a center of chirality in the substituent attached to the
NHC core at N1. All NHC precursors bore an aromatic
substituent on N3 and were prepared as a single enantiomer
Figure 4. X-ray structures of complexes 22i and 23a,c,d,e in two different representations. The solvent molecule of 23a is omitted for clarity.
F
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observed by GC-MS. The crude product was purified via column
chromatography using heptane and EtOAc as eluents. 2 was collected
as a yellow oil (58.5 g, 224 mmol, 89.5%). H NMR (400 MHz,
DMSO-d6): δ 7.76 (s, CH, 1 H), 7.21−7.07 (m, Ar-H, 3 H), 4.34 (q,
J = 7.0 Hz, CH2, 2 H), 2.73 (sp, J = 6.9 Hz, CH, 2 H), 1.32 (t, J = 7.0
Hz, CH3, 3 H), 1.09 (d, J = 6.9 Hz, CH3, 12 H). 13C NMR (100
MHz, DMSO-d6): δ 162.3, 155.8, 146.6, 135.9, 125.1, 123.0, 61.6,
27.3, 23.3, 14.0. HRMS: calcd for C16H23NO2 [M]+ 261.1729, found
261.1714.
using stereoselective transformations. The prepared carbene
precursors were converted to the corresponding NHC-silver
and NHC-gold complexes. The structures of the complexes
were characterized extensively in solution by NMR spectros-
copy. Several complexes were also crystallized and their solid-
state structures determined by X-ray crystallography. Both the
solution and solid-state structures revealed that the complex
formation resulted in the hindered rotation of the aromatic
substituent. In certain complexes this also led to the emergence
of axial chirality, with different degrees of stereoselectivity.
Testing of the utility of the prepared chiral NHC-silver and
NHC-gold complexes in asymmetric transformations is in
progress in our laboratory.
1
2-(2,6-Diisopropylanilino)-3,3-dimethylbutanoic Acid (3). A
solution of 40 g of 2 (153 mmol) in 765 mL of THF was cooled to
−78 °C under an inert atmosphere, and then 140 mL of tBuMgCl
(230 mmol) was added dropwise over 90 min. The resulting mixture
was stirred at −78 °C for 60 min, at which point complete conversion
was observed by GC-MS. The reaction mixture was quenched by the
addition of saturated aqueous NH4Cl solution, was warmed to room
temperature, and then was extracted with EtOAc. The combined
organic layers were dried over MgSO4, and the volatiles were removed
under reduced pressure. The crude product was purified via column
chromatography using heptane and EtOAc as eluents. 3 was collected
as a dark yellow oil (42.6 g, 133 mmol, 87.1%). 1H NMR (500 MHz,
DMSO-d6): δ 7.01 (d, J = 7.1 Hz, Ar-H, 2 H), 6.93 (dd, J = 8.1, 7.1
Hz, Ar-H, 1 H), 3.87 (m, NH, 1 H), 3.86 (m, CH, 1 H), 3.52 (d, J =
12.6 Hz, CH, 1 H), 3.32 (sp, J = 6.9 Hz, CH, 2 H), 1.15 (d, J = 6.8
Hz, CH3, 12 H), 1.10 (s, CH3, 9 H), 0.93 (t, J = 7.1 Hz, CH3, 3 H),
1.09 (d, J = 6.9 Hz, CH3, 12 H). 13C NMR (125 MHz, DMSO-d6): δ
172.9, 140.6, 140.4, 123.4, 123.0, 70.2, 59.6, 34.0, 26.7, 26.2, 24.2,
24.0, 13.9. HRMS: calcd for C20H34NO2 [M + H]+ 320.2584, found
320.2582.
2-(2,6-Diisopropylanilino)-3,3-dimethylbutanol (4a). A 10.8
g portion of LiAlH4 (284 mmol) was suspended in 284 mL of THF at
0 °C, and 30.2 g of 3 (94.5 mmol) was added in small portions. Then
the reaction mixture was warmed to 60 °C and stirred at that
temperature for 45 min, at which point complete conversion was
observed by LC-MS. The reaction mixture was cooled to 0 °C, and
10.8 mL of water, 21.6 mL of 2 N NaOH, and 21.6 mL of water were
added slowly to the mixture. MTBE was added to the mixture at the
previous temperature, and this mixture was stirred for 10 min. The
mixture was filtered and washed with MTBE. The crude product was
purified via column chromatography using heptane and EtOAc as
eluents. 4a was collected as a colorless oil (12.0 g, 43.3 mmol, 49.4%).
1H NMR (500 MHz, DMSO-d6): δ 7.01 (d, J = 7.6 Hz, Ar-H, 2 H),
6.89 (t, J = 7.6 Hz, Ar-H, 1 H), 4.40 (t, J = 4.2 Hz, OH, 1 H), 3.40/
3.28 (m, CH2, 2 H), 3.39 (d, J = 12.7 Hz, NH, 1 H), 3.36 (sp, J = 6.7
Hz, CH, 2 H), 2.73 (dm, J = 11.9 Hz, CH, 1 H), 1.16 (d, J = 6.7 Hz,
CH3, 6 H), 1.12 (d, J = 6.7 Hz, CH3, 6 H), 1.09 (s, CH3, 9 H). 13C
NMR (125 MHz, DMSO-d6): δ 142.1, 140.9, 123.2, 122.0, 67.5, 59.5,
34.8, 27.7, 26.6, 24.1, 23.9. HRMS: calcd for C18H32NO [M + H]+
278.2478, found 278.2323.
(2R)-2-(2,6-Diisopropylanilino)-3,3-dimethylbutanol (4b).
By chiral HPLC analysis 4b was a single enantiomer and was eluted
first from the racemate 4a on the (R,R) WHELK O-1 column using 2-
PrOH and heptane (0.5/99.5) as eluents. 4b was collected as a
colorless oil (5.0 g, 18.0 mmol, 50.0%). 1H NMR (500 MHz, DMSO-
d6): δ 7.01 (d, J = 7.6 Hz, Ar-H, 2 H), 6.89 (t, J = 7.6 Hz, Ar-H, 1 H),
4.39 (t, J = 4.2 Hz, OH, 1 H), 3.40/3.28 (m, CH2, 2 H), 3.39 (d, J =
12.7 Hz, NH, 1 H), 3.36 (sp, J = 6.7 Hz, CH, 2 H), 2.73 (dm, J = 11.9
Hz, CH, 1 H), 1.15 (d, J = 6.7 Hz, CH3, 6 H), 1.13 (d, J = 6.7 Hz,
CH3, 6 H), 1.09 (s, CH3, 9 H). 13C NMR (125 MHz, DMSO-d6): δ
142.1, 140.9, 123.2, 122, 67.4, 59.5, 34.8, 27.6, 26.6, 24.1, 23.9.
HRMS: calcd for C18H32N [M + H]+ 278.2478, found 278.2479.
(2S)-2-(2,6-Diisopropylanilino)-3,3-dimethylbutanol (4c). By
chiral HPLC analysis 4c was a single enantiomer and was eluted
second from the racemate 4a on the (R,R) WHELK O-1 column
using 2-PrOH and heptane (0.5/99.5) as eluents. 4c was collected as
a colorless oil (5.0 g, 18.0 mmol, 50.0%). 1H NMR (500 MHz,
DMSO-d6): δ 7.01 (d, J = 7.6 Hz, Ar-H, 2 H), 6.89 (t, J = 7.6 Hz, Ar-
H, 1 H), 4.39 (t, J = 4.2 Hz, OH, 1 H), 3.40/3.28 (m, CH2, 2 H), 3.39
(d, J = 12.6 Hz, NH, 1 H), 3.36 (sp, J = 6.7 Hz, CH, 2 H), 2.73 (dm, J
= 12.0 Hz, CH, 1 H), 1.15 (d, J = 6.7 Hz, CH3, 6 H), 1.13 (d, J = 6.7
EXPERIMENTAL SECTION
■
All reagents obtained from commercial sources were used without
further purification. Anhydrous solvents were obtained from
commercial sources and used without further drying. The reactions
were monitored using LCMS and GCMS instruments. Analytical LC-
MS: Agilent HP1200 LC with Agilent 6140 quadrupole MS, operating
in positive or negative ion electrospray ionization mode. The
molecular weight scan range was m/z 100−1350. Parallel UV
detection was done at 210 and 254 nm. Samples were supplied as 1
mM solutions in MeCN or in THF/water (1/1) with 5 μL loop
injection. LCMS analyses were performed on two instruments, one of
which was operated with basic and the other with acidic eluents. Basic
LCMS: Gemini-NX, 3 μm, C18, 50 mm × 3.00 mm i.d. column at 23
°C, flow rate of 1 mL min−1 using 5 mM aqueous NH4HCO3 solution
and MeCN as eluents. Acidic LCMS: ZORBAX Eclipse XDB-C18, 1.8
μm, 50 mm × 4.6 mm i.d. column at 40 °C, flow rate of 1 mL min−1
using water and MeCN as eluents, both containing 0.02 v/v% formic
acid. Combination gas chromatography and low-resolution mass
spectrometry were performed on an Agilent 6850 gas chromatograph
and Agilent 5975C mass spectrometer using a 15 m × 0.25 mm
column with 0.25 μm HP-5MS coating and helium as the carrier gas.
Ion source: EI+, 70 eV, 230 °C, quadrupole 150 °C, interface 300 °C.
Flash chromatography was performed on a ISCO CombiFlash Rf 200i
instrument with prepacked silica gel cartridges (RediSepRf Gold High
Performance). Chiral separations were performed on a KNAUER
Smartline Preparative HPLC system with a (R,R) WHELKO O-1 50
mm × 500 mm, 10 μm column running at a flow rate of 50 mL min−1
with UV diode array detection (210−285 nm). Chiral purity was
determined on an Agilent 1100 HPLC system with a WHELKO O-1,
250 mm × 4.6 mm, 10 μm column running at a flow rate of 1 mL
min−1 with UV diode array detection (210−285 nm).1H NMR and
proton-decoupled 13C NMR measurements were performed on a
Bruker Avance III 500 MHz spectrometer and a Bruker Avance III
400 MHz spectrometer, using DMSO-d6 or CDCl3 as solvent. 1H and
13C NMR data are in the form of δ values, given in parts per million
(ppm), using the residual peak of the solvent as an internal standard
(DMSO-d6, 2.50 ppm (1H)/39.5 ppm (13C); CDCl3, 7.26 ppm (1H)/
77.0 ppm (13C)). Splitting patterns are designated as s (singlet), d
(doublet), t (triplet), q (quartet), sp (septet), m (multiplet), br s
(broad singlet), dd (doublet of doublets), td (triplet of doublets), and
qd (quartet of doublets). In some cases two sets of signals appear in
the spectra due to hindered rotation. HRMS measurements were
determined on a Shimadzu IT-TOF, ion source temperature 200 °C,
ESI , ionization voltage (+,−)4.5 kV. The mass resolution was a
minimum of 10000. Melting points were determined by an OptiMelt
melting view apparatus at ramp rates of 2 °C min−1 in sealed glass
capillaries and are uncorrected. All products had an LC purity above
95% that was corroborated by their 1H NMR spectra unless
specifically mentioned otherwise.
Ethyl 2-(2,6-Diisopropylphenyl)iminoacetate (2). A 52 mL
portion of 2,6-diisopropylaniline (250 mmol) was added to 51 mL of
1 (250 mmol) dissolved in 1000 mL DIPE, and 0.5 mL of formic acid
was also added. The resulting mixture was stirred at room
temperature for 6 h, at which point complete conversion was
G
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Hz, CH3, 6 H), 1.09 (s, CH3, 9 H). 13C NMR (125 MHz, DMSO-d6):
δ 142.1, 140.9, 123.2, 122, 67.4, 59.5, 34.8, 27.6, 26.6, 24.1, 23.9.
HRMS: calcd for C18H32N [M + H]+ 278.2478, found 278.2470.
2-(2-tert-Butylanilino)-3,3-dimethylbutanol (4d). This com-
pound was prepared following the synthetic procedure described for
4a starting from 15.7 g of 19e (39.1 mmol). 4d was collected as a
colorless oil (8.09 g, 32.4 mmol, 83.0%). By chiral HPLC analysis 4d
was a single enantiomer and eluted second from the racemate on the
(R,R) WHELK O-1 column using 2-PrOH and heptane (1/99) as
eluents. 1H NMR (500 MHz, DMSO-d6): δ 7.10 (dd, J = 7.7, 1.4 Hz,
Ar-H, 1 H), 6.98 (td, J = 7.7, 1.4 Hz, Ar-H, 1 H), 6.70 (dm, J = 7.7
Hz, Ar-H, 1 H), 6.49 (td, J = 7.7, 1.4 Hz, Ar-H, 1 H), 4.65 (t, J = 4.5
Hz, OH, 1 H), 4.27 (d, J = 9.3 Hz, NH, 1 H), 3.60/3.57 (m+m, CH2,
DMSO-d6): δ 203.9, 142.2, 139.9, 123.9, 123.6, 75.7, 33.9, 27.0, 26.5,
24.2, 24.1. HRMS: calcd for C18H30NO [M + H]+ 276.2322, found
276.2320.
2-(2-tert-Butylanilino)-3,3-dimethylbutanal (5d). This com-
pound was prepared following the synthetic procedure described for
5a by starting from 2.97 g of 4e (11.9 mmol). 5d (racemic, 2.35 g)
was collected as a yellow solid and used without further purification
1
for the synthesis of 8i and 13g. H NMR (500 MHz, DMSO-d6): δ
9.83 (d, J = 1.8 Hz, CH, 1 H), 7.16 (dd, J = 7.7, 1.4 Hz, Ar-H, 1 H),
6.98 (td, J = 7.7, 1.4 Hz, Ar-H, 1 H), 6.60 (td, J = 7.7, 1.4 Hz, Ar-H, 1
H), 6.58 (d, J = 7.7 Hz, Ar-H, 1 H), 4.51 (d, J = 8.2 Hz, NH, 1 H),
4.17 (dd, J = 8.2, 1.8 Hz, CH, 1 H), 1.44 (s, CH3, 9 H), 1.08 (s, CH3,
9 H). 13C NMR (125 MHz, DMSO-d6): δ 205.2, 145.1, 132.9, 126.8,
126.1, 117.1, 111.4, 68.5, 35.3, 33.8, 29.7, 26.8. HRMS: calcd for
C16H26NO [M + H]+ 248.2009, found 248.2005.
2 H), 3.28 (m, CH, 1 H), 1.39 (s, CH3, 9 H) 1.01 (s, CH3, 9 H). 13
C
NMR (125 MHz, DMSO-d6): δ 146.4, 132.0, 126.8, 125.9, 115.3,
111.0, 60.9, 59.9, 35.0, 33.7, 29.7, 27.5. HRMS: calcd for C16H28NO
[M + H]+ 250.2165, found 250.2162.
(2S)-N-(2,6-Diisopropylphenyl)-3,3-dimethyl-N′-[(1S)-1-
phenylethyl]butane-1,2-diamine (8a). A 1.3 mL portion of (1S)-
1-phenylethanamine (10.5 mmol) was dissolved in 48 mL of EtOH
under an inert atmosphere, and then 2.62 g of 5c (9.51 mmol) was
added in one portion and 55 μL of acetic acid (0.95 mmol) was also
added. The mixture was stirred at 60 °C. The mixture in the first
reaction step was stirred for 1 h, until all of the 5c had reacted, ass
observed by GC-MS. When the starting material was reacted, the
mixture was cooled to room temperature and 1.44 g of NaBH4 (38.1
mmol) was added carefully. The mixture in the second reaction step
was stirred for 4 h at room temperature and observed by LC-MS. The
reaction mixture was quenched with the addition of saturated aqueous
NH4Cl solution, and then it was extracted with EtOAc. The combined
organic layers were dried over MgSO4. The volatiles were removed
under reduced pressure, and the residue was purified via column
chromatography using heptane and EtOAc as eluents. 8a was
2-(2-tert-Butylanilino)-3,3-dimethylbutanol (4e). This com-
pound was prepared following the synthetic procedure described for
4a starting from 6.22 g of 19f (15.5 mmol). 4e was collected as a
colorless oil (3.43 g, 13.7 mmol, 88.7%). By chiral HPLC analysis 4e
was a single enantiomer and eluted first from the racemate on the
(R,R) WHELK O-1 column using 2-PrOH and heptane (1/99) as
eluents. 1H NMR (500 MHz, DMSO-d6): δ 7.10 (dd, J = 7.7, 1.4 Hz,
Ar-H, 1 H), 6.98 (td, J = 7.7, 1.4 Hz, Ar-H, 1 H), 6.70 (dm, J = 7.7
Hz, Ar-H, 1 H), 6.49 (td, J = 7.7, 1.4 Hz, Ar-H, 1 H), 4.65 (t, J = 4.5
Hz, OH, 1 H), 4.26 (d, J = 9.3 Hz, NH, 1 H), 3.60/3.57 (m+m, CH2,
2 H), 3.28 (m, CH, 1 H), 1.39 (s, CH3, 9 H) 1.01 (s, CH3, 9 H). 13
C
NMR (125 MHz, DMSO-d6): δ 146.4, 132.0, 126.8, 125.9, 115.3,
111.0, 60.9, 59.9, 35.0, 33.7, 29.7, 27.5. HRMS: calcd for C16H28NO
[M + H]+ 250.2165, found 250.2160.
1
2-(2,6-Diisopropylanilino)-3,3-dimethylbutanal (5a). A 6.34
g portion of 4a (22.9 mmol) was dissolved in 549 mL of DCM and
then cooled to 0 °C, and 10.7 g of Dess-Martin periodine (25.1
mmol) was added in small portions. Then 453 μL of water (25.1
mmol) was also added and this mixture was stirred for 1.5 h, at which
point complete conversion was observed by LC-MS. The reaction
mixture was quenched with pentane and then filtered through a pad of
Celite. The solvent was removed under vacuum, and then more
pentane was added and the mixture filtered again. This method was
repeated twice, and 5a was collected as a yellow solid (6.29 g, 22.8
collected as a yellow oil (3.08 mg, 8.09 mmol, 85.0%). H NMR
(500 MHz, DMSO-d6): δ 7.26−7.04 (m, Ar-H, 5 H), 7.03 (d, J = 7.5
Hz, Ar-H, 2 H), 6.93 (t, J = 7.5 Hz, Ar-H, 1 H), 3.32 (sp, J = 6.7 Hz,
CH, 2 H), 3.32 (q, J = 6.6 Hz, CH, 1 H), 3.25 (d, J = 11.4 Hz, NH, 1
H), 2.96 (m, CH, 1 H), 2.48/2.32 (m+m, CH2, 2 H), 1.20 (br s, NH,
1 H), 1.17 (d, J = 6.7 Hz, CH3, 6 H), 1.12 (d, J = 6.7 Hz, CH3, 6 H),
0.96 (d, J = 6.6 Hz, CH3, 3 H), 0.94 (s, CH3, 9 H). 13C NMR (125
MHz, DMSO-d6): δ 146.0, 142.3, 140.5, 128.0, 126.4, 126.2, 123.5,
122.1, 67.3, 57.6, 48.8, 35.1, 27.1, 27.0, 24.6, 24.1, 23.9. HRMS: calcd
for C26H41N2 [M + H]+ 381.3264, found 381.3254.
1
mmol, 99.9%). Mp: 35−40 °C. H NMR (500 MHz, DMSO-d6): δ
(2S)-N-(2,6-Diisopropylphenyl)-3,3-dimethyl-N′-[(1R)-1-
phenylethyl]butane-1,2-diamine (8b). This compound was
prepared following the synthetic procedure described for 8a starting
from 1.33 mL of (1R)-1-phenylethanamine (10.5 mmol) and 2.62 g of
5c (9.51 mmol). The reaction time for the first step was 2.5 h and for
the second step was 4 h. 8b was collected as a yellow oil (2.78 g, 7.30
mmol, 76.8%). 1H NMR (500 MHz, DMSO-d6): δ 7.23−7.04 (m, Ar-
H, 5 H) 6.69 (d, J = 7.5 Hz, Ar-H, 2 H), 6.89 (t, J = 7.5 Hz, Ar-H, 1
H), 3.44 (q, J = 6.5 Hz, CH, 1 H), 3.35 (m, NH, 1 H), 3.35 (m, CH,
2 H), 3.01 (m, CH, 1 H), 2.37/2.34 (m+m, CH2, 2 H), 1.32 (br s,
NH, 1 H), 1.16 (d, J = 6.8 Hz, CH3, 6 H), 1.12 (d, J = 6.8 Hz, CH3, 6
H), 1.01 (d, J = 6.5 Hz, CH3, 3 H), 0.94 (s, CH3, 9 H). 13C NMR
(125 MHz, DMSO-d6): δ 145.9, 142.6, 139.9, 128.1, 126.4, 126.2,
123.4, 121.8, 66.0, 57.2, 48.4, 35.2, 27.2, 27.0, 24.4, 24.0, 23.9.
HRMS: calcd for C26H41N2 [M + H]+ 381.3264, found 381.3250.
(2S)-N-(2,6-Diisopropylphenyl)-3,3-dimethyl-N′-[(1S)-1-(1-
naphthyl)ethyl]butane-1,2-diamine (8c). This compound was
prepared following the synthetic procedure described for 8a starting
from 1.38 mL of (1S)-1-(1-naphthyl)ethanamine (8.59 mmol) and
2.15 g of 5c (7.81 mmol). The reaction time for the first step was 1.5
h and for the second step was 2 h. 8c was collected as a yellow oil
(2.83 g, 6.58 mmol, 84.3%). 1H NMR (500 MHz, DMSO-d6): δ
8.18−7.25 (m, Ar-H, 7 H), 7.00 (d, J = 7.6 Hz, Ar-H, 2 H), 6.89 (t, J
= 7.6 Hz, Ar-H, 1 H), 4.32 (q, J = 6.8 Hz, CH, 1 H), 3.39 (br d, NH,
1 H), 3.37 (sp, J = 6.8 Hz, CH, 2 H), 3.07 (m, CH, 1 H), 2.53 (m,
CH2, 2 H), 1.56 (br s, NH, 1 H), 1.16 (d, J = 6.7 Hz, CH3, 6 H), 1.16
(d, J = 6.4 Hz, CH3, 3 H), 1.11 (d, J = 6.7 Hz, CH3, 6 H), 0.93 (s,
CH3, 9 H). 13C NMR (125 MHz, DMSO-d6): δ 142.6, 141.3, 139.9,
133.4, 130.7, 128.7, 126.6, 125.7, 125.6, 125.2, 123.4, 122.8, 122.4,
9.64 (d, J = 5.1 Hz, CH, 1 H), 7.02 (m, Ar-H, 2 H), 6.97 (dd, J = 8.7,
6.3 Hz, Ar-H, 1 H), 4.02 (d, J = 10.9 Hz, NH, 1 H), 3.33 (sp, J = 6.8
Hz, CH, 2 H), 3.06 (dd, J = 10.9 Hz, J = 5.1 Hz, CH, 1 H), 1.17 (d, J
= 6.8 Hz, CH3, 6 H), 1.12 (d, J = 6.8 Hz, CH3, 6 H), 1.12 (s, CH3, 9
H). 13C NMR (125 MHz, DMSO-d6): δ 203.9, 142.2, 139.9, 123.9,
123.6, 75.7, 33.9, 27.0, 26.5, 24.2, 24.1. HRMS: calcd for C18H30NO
[M + H]+ 276.2322, found 276.2323.
(2R)-2-(2,6-Diisopropylanilino)-3,3-dimethylbutanal (5b).
This compound was prepared following the synthetic procedure
described for 5a starting from 4.20 g of 4b (15.1 mmol). 5b was
collected as a yellow solid (4.12 mg, 15.0 mmol, 98.8%). Mp: 65−75
°C. 1H NMR (500 MHz, DMSO-d6): δ 9.64 (d, J = 5.1 Hz, CH, 1 H),
7.02 (m, Ar-H, 2 H), 6.97 (dd, J = 8.7, 6.3 Hz, Ar-H, 1 H), 4.02 (d, J
= 11.0 Hz, NH, 1 H), 3.33 (sp, J = 6.8 Hz, CH, 2 H), 3.07 (dd, J =
11.0 Hz, J = 5.1 Hz, CH, 1 H), 1.16 (d, J = 6.8 Hz, CH3, 6 H), 1.12
(d, J = 6.8 Hz, CH3, 6 H), 1.11 (s, CH3, 9 H). 13C NMR (125 MHz,
DMSO-d6): δ 203.9, 142.2, 139.9, 123.9, 123.6, 75.7, 33.9, 27.0, 26.5,
24.2, 24.1. HRMS: calcd for C18H30NO [M + H]+ 276.2322, found
276.2325.
(2S)-2-(2,6-Diisopropylanilino)-3,3-dimethylbutanal (5c).
This compound was prepared following the synthetic procedure
described for 5a starting from 3.40 g of 4c (12.3 mmol). 5c was
collected as a yellow solid (3.36 g, 12.2 mmol, 99.5%). Mp: 70−80
°C. 1H NMR (500 MHz, DMSO-d6): δ 9.64 (d, J = 5.1 Hz, CH, 1 H),
7.02 (m, Ar-H, 2 H), 6.97 (dd, J = 8.7, 6.2 Hz, Ar-H, 1 H), 4.03 (d, J
= 10.6 Hz, NH, 1 H), 3.33 (sp, J = 6.8 Hz, CH, 2 H), 3.07 (dd, J =
10.6 Hz, J = 5.1 Hz, CH, 1 H), 1.17 (d, J = 6.8 Hz, CH3, 6 H), 1.12
(d, J = 6.8 Hz, CH3, 6 H), 1.12 (s, CH3, 9 H). 13C NMR (125 MHz,
H
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121.8, 66.5, 52.9, 48.5, 27.2, 27.0, 24.0, 23.9, 23.6. HRMS: calcd for
C30H42N2 [M + H]+ 431.3420, found 431.3418.
following the synthetic procedure described for 8a starting from 1.25
mL of 2-tert-butylaniline (7.99 mmol) and 2.00 g of 5c (7.26 mmol).
The reaction time for the first step was 16 h and for the second step
was 3 h at 60 °C with 827 mg of LiAlH4 (21.8 mmol) as the reductive
agent. 8h was collected as a yellow oil (2.15 g, 5.26 mmol, 72.4%). 1H
NMR (500 MHz, DMSO-d6): δ 7.08 (dd, J = 7.7, 1.2 Hz, Ar-H, 1 H),
6.98 (td, J = 7.7, 1.2 Hz, Ar-H, 1 H), 6.97 (d, J = 7.7 Hz, Ar-H, 2 H),
6.83 (t, J = 7.7 Hz, Ar-H, 1 H), 6.55 (td, J = 7.7, 1.2 Hz, Ar-H, 1 H),
6.51 (dd, J = 7.7, 1.2 Hz, Ar-H, 1 H), 4.60 (d, J = 6.2 Hz, NH, 1 H),
3.76 (d, J = 11.6 Hz, NH, 1 H), 3.46/3.04 (m+m, CH2, 2 H), 3.38
(m, CH, 1 H), 3.30 (sp, J = 6.7 Hz, CH, 2 H), 1.25 (s, CH3, 9 H),
1.11 (d, J = 6.7 Hz, CH3, 12 H), 0.93 (s, CH3, 9 H). 13C NMR (125
MHz, DMSO-d6): δ 146.7, 143.0, 138.8, 132.9, 126.8, 125.6, 123.6,
121.3, 116.3, 111.5, 65.1, 44.9, 36.5, 33.8, 31.3, 29.4, 27.3, 27.1, 24.4.
HRMS: calcd for C27H43N2 [M + H]+ 409.3577, found 409.3567.
(4S)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1S)-1-phe-
nylethyl]-4,5-dihydroimidazolium Chloride (9a). A 2.50 g
portion of 8a (6.49 mmol) was dissolved in 33 mL of HC(OEt)3
(194 mmol), and 382 mg of NH4Cl (7.14 mmol) was added in one
portion. The mixture was heated to reflux temperature and was stirred
for 75 min, at which point complete conversion was observed by
HPLC-MS. The volatiles were removed under reduced pressure, and
the residue was purified via column chromatography using DCM and
1.2% methanolic ammonia as eluents. The crude product was
recrystallized from DCM-Et2O. 9a was collected as a white solid (1.27
g, 2.97 mmol, 45.8%). Mp: 213-215 °C. 1H NMR (500 MHz, DMSO-
d6): δ 9.05 (s, CH, 1 H), 7.52−7.40 (m, Ar-H, 5 H), 7.49 (t, J = 7.7
Hz, Ar-H, 1 H), 7.39 (dd, J = 7.7, 1.5 Hz, Ar-H, 1 H), 7.38 (dd, J =
7.7, 1.5 Hz, Ar-H, 1 H), 5.05 (q, J = 7.0 Hz, CH, 1 H), 4.44 (dd, J =
12.3, 9.2 Hz, CH, 1 H), 4.13/3.94 (t+dd, J = 12.3 Hz, J = 12.3, 9.2
Hz, CH2, 2 H), 3.20 (sp, J = 6.8 Hz, CH, 1 H), 2.90 (sp, J = 6.8 Hz,
CH, 1 H), 1.72 (d, J = 7.0 Hz, CH3, 3 H), 1.31 (d, J = 6.8 Hz, CH3, 3
H), 1.29 (d, J = 6.8 Hz, CH3, 3 H), 1.23 (d, J = 6.8 Hz, CH3, 3 H),
1.18 (d, J = 6.8 Hz, CH3, 3 H), 0.73 (s, CH3, 9 H). 13C NMR (125
MHz, DMSO-d6): δ 158.5, 145.5, 145.2, 138.5, 132.1, 130.4, 129.2,
128.8, 126.5, 125.5, 125.3, 73.8, 57.6, 49.4, 34.9, 28.3, 28, 25.8, 25.5,
25.2, 23.2, 22.6, 19.1. HRMS: calcd for C27H39N2 [M − Cl−]+
391.3108, found 391.3113.
(2S)-N-(2,6-Diisopropylphenyl)-3,3-dimethyl-N′-[(1R)-1-(1-
naphthyl)ethyl]butane-1,2-diamine (8d). This compound was
prepared following the synthetic procedure described for 8a starting
from 1.28 mL of (1R)-1-(1-naphthyl)ethanamine (7.99 mmol) and
2.00 g of 5c (7.26 mmol). The reaction time for the first step was 1 h
and for the second step was 4 h. 8d was collected as a yellow oil (2.25
g, 5.22 mmol, 71.9%). 1H NMR (500 MHz, DMSO-d6): δ 8.18−7.37
(m, Ar-H, 7 H), 7.01 (d, J = 7.6 Hz, Ar-H, 2 H), 6.89 (t, J = 7.6 Hz,
Ar-H, 1 H), 4.20 (q, J = 6.8 Hz, CH, 1 H), 3.39 (sp, J = 6.8 Hz, CH, 2
H), 3.34 (d, J = 11.7 Hz, NH, 1 H), 3.09 (m, CH, 1 H), 2.62/2.46 (m
+dd, J = 11.7, 6.9 Hz, CH2, 2 H), 1.17 (d, J = 6.8 Hz, CH3, 6 H), 1.14
(d, J = 6.8 Hz, CH3, 6 H), 1.10 (d, J = 6.8 Hz, CH3, 3 H), 0.91 (s,
CH3, 9 H). 13C NMR (125 MHz, DMSO-d6): δ 142.5, 141.2, 140.1,
133.5, 130.7, 128.6, 126.7, 125.6, 125.5, 125.2, 123.4, 123.0, 122.5,
121.9, 67.4, 54.0, 49.6, 27.1, 27.0, 24.1, 23.9, 23.8. HRMS: calcd for
C30H42N2 [M + H]+ 431.3420, found 431.3427.
(2S)-N-(2,6-Diisopropylphenyl)-3,3-dimethyl-N′-[(1S)-1,2,2-
trimethylpropyl]butane-1,2-diamine (8e). This compound was
prepared following the synthetic procedure described for 8a starting
from 1.07 mL of (2S)-3,3-dimethylbutan-2-amine (7.99 mmol) and
2.00 g of 5c (7.26 mmol). The reaction time for the first step was 2 h
and for the second step was 4 h. 8e was collected as a yellow oil (1.95
g, 5.41 mmol, 74.5%). 1H NMR (400 MHz, DMSO-d6): δ 7.00 (d, J =
7.7 Hz, Ar-H, 2 H), 6.86 (t, J = 7.7 Hz, Ar-H, 1 H), 3.35 (sp, J = 6.7
Hz, CH, 2 H), 3.29 (d, J = 11.7 Hz, NH, 1 H), 3.06 (m, CH, 1 H),
2.74/2.51 (dd+m, J = 11.7, 7.5 Hz, CH2, 2 H), 1.90 (br., CH, 1 H),
1.18 (d, J = 6.7 Hz, CH3, 12 H), 1.00 (s, CH3, 9 H), 0.67 (d, J = 6.5
Hz, CH3, 3 H), 0.60 (s, CH3, 9 H). 13C NMR (100 MHz, DMSO-d6):
δ 142.7, 139.6, 123.4, 121.7, 67.3, 61.4, 51.1, 34.9, 34.2, 27.2, 27.1,
26.1, 24.0, 23.8, 14.2. HRMS: calcd for C24H44N2 [M + H]+
361.3577, found 361.3583.
(2S)-N-(2,6-Diisopropylphenyl)-3,3-dimethyl-N′-[(1R)-1,2,2-
trimethylpropyl]butane-1,2-diamine (8f). This compound was
prepared following the synthetic procedure described for 8a starting
from 1.12 mL of (2R)-3,3-dimethylbutan-2-amine (8.39 mmol) and
2.10 g of 5c (7.63 mmol). The reaction time for the first step was 2 h
and for the second step was 4 h. 8f was collected as a yellow oil (1.84
(4S)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1R)-1-phe-
nylethyl]-4,5-dihydroimidazolium Chloride (9b). This com-
pound was prepared following the synthetic procedure described for
9a starting from 2.78 g of 8b (7.30 mmol). 9b was collected as a white
1
g, 5.09 mmol, 66.7%). A yellow oil was obtained. H NMR (500
MHz, DMSO-d6): δ 7.01 (d, J = 7.7 Hz, Ar-H, 2 H), 6.86 (t, J = 7.7
Hz, Ar-H, 1 H), 3.32 (sp, J = 6.8 Hz, CH, 2 H), 3.29 (d, J = 8.2 Hz,
NH, 1 H), 3.01 (m, CH, 1 H), 2.84/2.28 (m+dd, J = 11.6, 6.2 Hz,
CH2, 2 H), 1.90 (q, J = 6.3 Hz, CH, 1 H), 1.18 (d, J = 6.8 Hz, CH3, 6
H), 1.17 (d, J = 6.8 Hz, CH3, 6 H), 1.01 (s, CH3, 9 H), 0.79 (br s,
NH, 1 H), 0.68 (d, J = 6.3 Hz, CH3, 3 H), 0.58 (s, CH3, 9 H). 13C
NMR (125 MHz, DMSO-d6): δ 142.2, 139.8, 123.5, 121.8, 67.2, 61.9,
49.6, 35.2, 33.8, 27.1, 26.1, 24.0, 14.2. HRMS: calcd for C24H44N2 [M
+ H]+ 361.3577, found 361.3588.
(2S)-N-(2,6-Diisopropylphenyl)-N′-(2-isopropylphenyl)-3,3-
dimethylbutane-1,2-diamine (8g). This compound was prepared
following the synthetic procedure described for 8a starting from 1.13
mL of 2-isopropylaniline (7.99 mmol) and 2.10 g of 5c (7.63 mmol).
The reaction time for the first step was 7 h and for the second step
was 30 min with 827 mg of LiAlH4 (21.8 mmol) as the reductive
agent. 8g was collected as a yellow oil (2.26 g, 5.74 mmol, 79.0%). 1H
NMR (500 MHz, DMSO-d6): δ 7.02 (d, J = 7.6 Hz, Ar-H, 2 H), 6.93
(dm, J = 7.4 Hz, Ar-H, 1 H), 6.92 (t, J = 7.6 Hz, Ar-H, 1 H), 6.90 (td,
J = 7.4, 1.1 Hz, Ar-H, 1 H), 6.52 (td, J = 7.4, 1.1 Hz, Ar-H, 1 H), 6.34
(dd, J = 7.4, 1.1 Hz, Ar-H, 1 H), 4.12 (d, J = 6.7 Hz, NH, 1 H), 3.50
(d, J = 11.1 Hz, NH, 1 H), 3.49/2.98 (m+m, CH2, 2 H), 3.30 (sp, J =
6.8 Hz, CH, 2 H), 3.22 (m, CH, 1 H), 2.04 (m, J = 6.8 Hz, CH, 1 H),
1.10/1.06 (d+d, J = 6.8 Hz, J = 6.8 Hz, CH3, 12 H), 1.06 (s, CH3, 9
H), 0.95/0.94 (d+d, J = 6.8 Hz, J = 6.8 Hz, CH3, 6 H). 13C NMR
(125 MHz, DMSO-d6): δ 144.6, 142.5, 140.0, 131.6, 126.3, 124.3,
123.7, 122.0, 116.2, 109.3, 65.2, 45.6, 35.6, 27.1, 27.0, 25.7, 24.1, 24.0,
22.2, 22.1. HRMS: calcd for C27H43N2 [M + H]+ 395.3421, found
395.3436.
1
solid (1.12 g, 2.62 mmol, 35.9%). Mp: 164−166 °C. H NMR (400
MHz, DMSO-d6): δ 9.12 (s, CH, 1 H), 7.55−7.41 (m, Ar-H, 5 H),
7.47 (t, J = 7.8 Hz, Ar-H, 1 H), 7.38 (dd, J = 7.8, 1.5 Hz, Ar-H, 1 H),
7.35 (dd, J = 7.8, 1.5 Hz, Ar-H, 1 H), 5.27 (q, J = 7.0 Hz, CH, 1 H),
4.37 (dd, J = 12.4, 8.8 Hz, CH, 1 H), 4.07/3.94 (t+dd, J = 12.4 Hz, J
= 12.4, 8.8 Hz, CH2, 2 H), 3.23 (sp, J = 6.7 Hz, CH, 1 H), 2.83 (sp, J
= 6.7 Hz, CH, 1 H), 1.76 (d, J = 7.0 Hz, CH3, 3 H), 1.30 (d, J = 6.7
Hz, CH3, 3 H), 1.29 (d, J = 6.7 Hz, CH3, 3 H), 1.23 (d, J = 6.7 Hz,
CH3, 3 H), 1.11 (d, J = 6.7 Hz, CH3, 3 H), 0.76 (s, CH3, 9 H). 13C
NMR (100 MHz, DMSO-d6): δ 159.3, 145.5, 145.3, 137.7, 132.1,
130.3, 129.1, 128.8, 126.9, 125.4, 125.3, 74.1, 56.9, 47.8, 35.1, 28.3,
28.0, 26.0, 25.4, 25.2, 23.2, 22.6, 17.7. HRMS: calcd for C27H39N2 [M
− Cl−]+ 391.3108, found 391.2852.
(4S)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1S)-1-(1-
naphthyl)ethyl]-4,5-dihydroimidazolium Chloride (9c). This
compound was prepared following the synthetic procedure described
for 9a starting from 2.84 g of 8c (6.580 mmol). 9c was collected as a
white solid (2.03 mg, 4.26 mmol, 64.7%). Mp: 272−274 °C. 1H NMR
(500 MHz, DMSO-d6): δ 8.87 (s, CH, 1 H), 8.21−7.58 (m, Ar-H, 6
H), 7.79 (d, J = 7.0 Hz, Ar-H, 1 H), 7.43 (t, J = 7.8 Hz, Ar-H, 1 H),
7.30 (d, J = 7.8 Hz, Ar-H, 2 H), 6.03 (q, J = 6.8 Hz, CH, 1 H), 4.37
(dd, J = 12.5, 8.5 Hz, CH, 1 H), 4.19/3.97 (dd+t, J = 12.5, 8.5 Hz, J =
12.5 Hz, CH2, 2 H), 2.95 (sp, J = 6.8 Hz, CH, 1 H), 2.71 (sp, J = 6.8
Hz, CH, 1 H), 1.94 (d, J = 6.8 Hz, CH3, 3 H), 1.21 (d, J = 6.8 Hz,
CH3, 3 H), 1.20 (d, J = 6.8 Hz, CH3, 3 H), 1.02 (d, J = 6.8 Hz, CH3, 3
H), 0.91 (d, J = 6.8 Hz, CH3, 3 H), 0.77 (s, CH3, 9 H), 13C NMR
(125 MHz, DMSO-d6): δ 159.0, 145.3, 145.0, 133.7, 131.9, 131.6,
130.4, 130.2, 129.8, 129.2, 127.1, 126.3, 125.5, 125.4, 125.2, 122.6,
(2S)-N′-(2-tert-Butylphenyl)-N-(2,6-diisopropylphenyl)-3,3-
dimethylbutane-1,2-diamine (8h). This compound was prepared
I
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Article
73.8, 53.2, 48.0, 35.1, 28.1, 28.0, 25.5, 25.2, 23.2, 22.5, 17.9. HRMS:
calcd for C31H41N2 [M − Cl−]+ 441.3264, found 441.3253.
(4S)-4-tert-Butyl-1-(2-tert-butylphenyl)-3-(2,6-diisopropyl-
phenyl)-4,5-dihydroimidazolium Chloride (9h). This compound
was prepared following the synthetic procedure described for 9a
starting from 2.10 g of 8h (5.14 mmol). 9h was collected as a
yellowish white solid (1.90 mg, 4.16 mmol, 81.0%). Mp: 230−245 °C.
1H NMR (500 MHz, DMSO-d6): δ 9.26 (s, CH, 1 H), 7.75−7.45 (m,
Ar-H, 4 H), 7.53 (t, J = 7.9 Hz, Ar-H, 1 H), 7.40 (d, J = 7.9 Hz, Ar-H,
2 H), 4.88 (t, J = 11.3 Hz, CH, 1 H), 4.82/4.42 (t+t, J = 11.3 Hz, J =
11.3 Hz, CH2, 2 H), 3.33 (sp, J = 6.7 Hz, CH, 1 H), 3.16 (sp, J = 6.7
Hz, CH, 1 H), 1.48 (s, CH3, 9 H), 1.43/1.16 (d+d, J = 6.7 Hz, J = 6.7
Hz, CH3, 3 H), 1.38/1.19 (d+d, J = 6.7 Hz, J = 6.7 Hz, CH3, 3 H),
0.87 (s, CH3, 9 H). 13C NMR (125 MHz, DMSO-d6): δ 145.4, 138.0,
133.8, 130.8, 130.7, 130.1, 129.4, 128.1, 125.6, 56.8, 34.6, 32.0, 28.2,
26.0, 25.7, 25.4, 23.0. HRMS: calcd for C28H41N2 [M − Cl−]+
419.3426, found 419.3404.
(4S)-4-tert-Butyl-3-(2-tert-butylphenyl)-1-[(1S)-1-phenyleth-
yl]-4,5-dihydroimidazolium Chloride (9i). This compound was
prepared following the synthetic procedure described for 9a starting
from 315 mg of 8i (0.893 mmol). 9i was collected as a light yellow
solid (63 mg, 0.158 mmol, 17.7%). 1H NMR (500 MHz, DMSO-d6):
δ 9.13 (s, CH, 1 H), 7.71 (dd, J = 7.7, 1.4 Hz, Ar-H, 1 H), 7.62 (dd, J
= 7.7, 1.4 Hz, Ar-H, 1 H), 7.48−7.40 (m, Ar-H, 5 H), 7.49 (td, J =
7.7, 1.4 Hz, Ar-H, 1 H), 7.39 (td, J = 7.7, 1.4 Hz, Ar-H, 1 H), 4.98 (q,
J = 7.0 Hz, CH, 1 H), 4.51 (dd, J = 11.0, 8.1 Hz, CH, 1 H), 3.87 (m,
CH2, 2 H), 1.72 (d, J = 7.0 Hz, CH3, 3 H), 1.40 (s, CH3, 9 H), 0.71
(s, CH3, 9 H). 13C NMR (125 MHz, DMSO-d6): δ 157.6, 146.5,
138.4, 134.5, 131.6, 130.3, 130.1, 129.1, 128.7, 127.1, 126.8, 73.1,
57.5, 49.5, 35.4, 31.8, 25.2, 19.5. HRMS: calcd for C25H35N2 [M −
Cl−]+ 363.2800, found 363.2787.
(2R)-N-(2,6-Diisopropylphenyl)-N′-[(4-methoxyphenyl)-
methyl]-3,3-dimethylbutane-1,2-diamine (10). This compound
was prepared following the synthetic procedure described for 8a
starting from 3.94 mL of 4-methoxyphenyl)methanamine (30.2
mmol) and 7.55 g of 5b (27.4 mmol). The reaction time for the
first step was 2 h and for the second step was 16 h. 10 was collected as
a colorless oil (7.01 g, 17.7 mmol, 64.5%). A colorless oil was
obtained. 1H NMR (500 MHz, DMSO-d6): δ 7.00 (d, J = 7.6 Hz, Ar-
H, 2 H), 6.97 (m, Ar-H, 2 H), 6.89 (t, J = 7.6 Hz, Ar-H, 1 H), 6.76
(m, Ar-H, 2 H), 3.69 (s, CH3, 3 H), 3.39 (s, CH2, 2 H), 3.36 (sp, J =
6.8 Hz, CH, 2 H), 3.35 (m, NH, 1 H), 3.01 (m, CH, 1 H), 2.61/2.51
(dd+dm, J = 12.4, 4.2 Hz, J = 4.2 Hz, CH2, 2 H), 1.33 (brs, NH, 1 H),
1.15 (d, J = 6.8 Hz, CH3, 6 H), 1.13 (d, J = 6.8 Hz, CH3, 6 H), 0.99
(s, CH3, 9 H). 13C NMR (125 MHz, DMSO-d6): δ 157.8, 142.5,
140.1, 132.6, 128.5, 123.4, 121.9, 113.4, 66.7, 54.9, 52.6, 50.2, 35.3,
27.3, 26.9, 24.1, 24.0. HRMS: calcd for C26H41N2O [M + H]+
397.3213, found 397.3217. The stereochemical integrity of the
product was not investigated.
(4S)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1R)-1-(1-
naphthyl)ethyl]-4,5-dihydroimidazolium Chloride (9d). This
compound was prepared following the synthetic procedure described
for 9a starting from 2.25 g of 8d (5.22 mmol). 9d was collected as a
1
white solid (1.90 g, 3.98 mmol, 76.1%). Mp: 261−263 °C. H NMR
(500 MHz, CDCl3): δ 10.40 (s, CH, 1 H), 8.72 (d, J = 8.5 Hz, Ar-H,
1 H), 8.00−7.32 (m, Ar-H, 6 H) 7.35 (t, J = 7.8 Hz, Ar-H, 1 H), 7.19/
7.17 (dd+dd, J = 7.8, 1.5 Hz, J = 7.8, 1.5 Hz, Ar-H, 2 H), 4.21 (m,
CH, 1 H), 4.20/3.25 (m+dd, J = 8.7, 4.0 Hz, CH2, 2 H), 3.00 (sp, J =
6.8 Hz, CH, 1 H), 2.89 (sp, J = 6.8 Hz, CH, 1 H), 2.02 (d, J = 6.8 Hz,
CH3, 3 H), 1.45 (d, J = 6.8 Hz, CH3, 3 H), 1.34 (d, J = 6.8 Hz, CH3, 3
H), 1.27 (d, J = 6.8 Hz, CH3, 3 H), 1.18 (d, J = 6.8 Hz, CH3, 3 H),
0.36 (s, CH3, 9 H). 13C NMR (125 MHz, CDCl3): δ 160.3, 145.6,
145.3, 134.3, 132.3, 131.8, 131.3, 130.5, 130.3, 129.2, 127.7, 126.6,
125.7, 125.6, 124.9, 124.6, 124.0, 73.5, 53.4, 46.6, 35.5, 29.5, 28.6,
26.9, 25.8, 25.5, 23.8, 23.0, 17.1. HRMS: calcd for C31H41N2 [M −
Cl−]+ 441.3264, found 441.3265.
(4S)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1S)-1,2,2-tri-
methylpropyl]-4,5-dihydroimidazolium Chloride (9e). This
compound was prepared following the synthetic procedure described
for 9a starting from 1.95 g of 8e (5.41 mmol). 9e was collected as a
1
white solid (1.80 g, 4.42 mmol, 81.8% Yield). Mp: 130−148 °C. H
NMR (500 MHz, DMSO-d6): δ 9.00 (s, CH, 1 H), 7.49 (t, J = 7.7 Hz,
Ar-H, 1 H), 7.38 (dd, J = 7.7, 1.5 Hz, Ar-H, 1 H), 7.37 (dd, J = 7.7,
1.5 Hz, Ar-H, 1 H), 4.55 (dd, J = 12.0, 10.2 Hz, CH, 1 H), 4.48/4.02
(t+dd, J = 12.0 Hz, J = 12.0, 10.2 Hz, CH2, 2 H), 3.77 (q, J = 7.1 Hz,
CH, 1 H), 3.18 (sp, J = 6.8 Hz, CH, 1 H), 2.98 (sp, J = 6.8 Hz, CH, 1
H), 1.37 (d, J = 7.1 Hz, CH3, 3 H), 1.34 (d, J = 6.8 Hz, CH3, 3 H),
1.30 (d, J = 6.8 Hz, CH3, 3 H), 1.19 (d, J = 6.8 Hz, CH3, 3 H), 1.13
(d, J = 6.8 Hz, CH3, 3 H), 0.99 (s, CH3, 9 H), 0.82 (s, CH3, 9 H). 13
C
NMR (125 MHz, DMSO-d6): δ 162.9, 160.5, 145.8, 145.5, 131.8,
130.5, 125.5, 125.2, 73.9, 62.9, 50.8, 35.0, 34.6, 28.2, 28.2, 26.4, 25.9,
25.5, 25.4, 23.0, 22.5, 13.3. HRMS: calcd for C25H43N2 [M − Cl−]+
371.3426, found 371.3423.
(4S)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1R)-1,2,2-tri-
methylpropyl]-4,5-dihydroimidazolium Chloride (9f). This
compound was prepared following the synthetic procedure described
for 9a starting from 1.84 g of 8f (5.09 mmol). 9f was collected as a
white solid (845 mg, 2.08 mmol, 40.8%). Mp: 259−261 °C. 1H NMR
(500 MHz, DMSO-d6): δ 8.95 (s, CH, 1 H), 7.47 (t, J = 7.7 Hz, Ar-H,
1 H), 7.37 (dm, J = 7.7 Hz, Ar-H, 2 H), 4.45/4.07 (m+m, CH2, 2 H),
4.45 (m, CH, 1 H), 3.80 (q, J = 7.0 Hz, CH, 1 H), 3.26 (sp, J = 6.8
Hz, CH, 1 H), 2.97 (sp, J = 6.8 Hz, CH, 1 H), 1.37 (d, J = 7.0 Hz,
CH3, 3 H), 1.35 (d, J = 6.8 Hz, CH3, 3 H), 1.29 (d, J = 6.8 Hz, CH3, 3
H), 1.21 (d, J = 6.8 Hz, CH3, 3 H), 1.10 (d, J = 6.8 Hz, CH3, 3 H),
0.99 (s, CH3, 9 H), 0.81 (s, CH3, 9 H). 13C NMR (125 MHz, DMSO-
d6): δ 160.4, 145.8, 145.6, 131.9, 130.4, 125.4, 125.2, 74.1, 62.9, 49.5,
34.8, 34.6, 28.2, 27.9, 26.5, 26.0, 25.6, 25.3, 23.2, 22.5, 13.2. HRMS:
calcd for C25H43N2 [M − Cl−]+ 371.3426, found 371.3422.
(4S)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-(2-isopropyl-
phenyl)-4,5-dihydroimidazolium Chloride (9g). This compound
was prepared following the synthetic procedure described for 9a
starting from 2.26 g of 8g (5.73 mmol). 9g was collected as a
yellowish white solid (1.94 g, 4.39 mmol, 76.7%). Mp: 60−65 °C. 1H
NMR (500 MHz, DMSO-d6): δ 9.27 (s, CH, 1 H), 7.67 (dd, J = 7.9,
1.2 Hz, Ar-H, 1 H), 7.60 (dd, J = 7.9, 1.2 Hz, Ar-H, 1 H), 7.57 (td, J =
7.9, 1.2 Hz, Ar-H, 1 H), 7.51 (t, J = 7.7 Hz, Ar-H, 1 H), 7.46 (td, J =
7.9, 1.2 Hz, Ar-H, 1 H), 7.41 (dm, J = 7.7 Hz, Ar-H, 1 H), 7.41 (dm, J
= 7.7 Hz, Ar-H, 1 H), 4.85/4.47 (t+dd, J = 11.8 Hz, J = 11.8, 10.2 Hz,
CH2, 2 H), 4.72 (dd, J = 11.8, 10.2 Hz, CH, 1 H), 3.33 (sp, J = 6.8
Hz, CH, 1 H), 3.15 (sp, J = 6.8 Hz, CH, 1 H), 3.06 (sp, J = 6.8 Hz,
CH, 1 H), 1.42/1.16 (d+d, J = 6.8 Hz, J = 6.8 Hz, CH3, 6 H), 1.36/
1.19 (d+d, J = 6.8 Hz, J = 6.8 Hz, CH3, 6 H), 1.30/1.26 (d+d, J = 6.8
Hz, J = 6.8 Hz, CH3, 6 H), 0.88 (s, CH3, 9 H). 13C NMR (125 MHz,
DMSO-d6): δ 160.8, 145.6, 145.3, 144.6, 133.0, 131.4, 130.7, 127.4,
127.3, 126.9, 125.6, 125.3, 75.0, 55.1, 34.9, 28.5, 28.2, 27.8, 25.8, 25.7,
25.4, 23.7, 23.6, 23.1, 22.5. HRMS: calcd for C28H41N2 [M − Cl−]+
405.3270, found 405.3255.
(2R)-N-(2,6-Diisopropylphenyl)-3,3-dimethylbutane-1,2-di-
amine (11). A 1.80 g portion of 10 (4.54 mmol) was dissolved in 23
mL of EtOH, and 483 mg of palladium (0.454 mmol) was added
carefully. The reaction was carried out in an autoclave under 10 bar
pressure at room temperature. After 24 h complete conversion was
observed by HPLC-MS. The crude product was purified via column
chromatography using DCM and 1.2% methanolic ammonia as
eluents. 11 was collected as a colorless oil (1.19 g, 4.32 mmol, 95.2%).
1H NMR (500 MHz, DMSO-d6): δ 7.00 (d, J = 7.6 Hz, Ar-H, 2 H),
6.87 (t, J = 7.6 Hz, Ar-H, 1 H), 3.38 (sp, J = 6.8 Hz, CH, 2 H), 3.38
(d, J = 5.0 Hz, NH, 1 H), 2.85 (m, CH, 1 H), 2.66/2.58 (dd+dd, J =
13.1, 5.0 Hz, J = 13.1 Hz, J = 5.0 Hz, CH2, 2 H), 1.20 (br s, NH2, 2
H), 1.16 (d, J = 6.8 Hz, CH3, 6 H), 1.15 (d, J = 6.8 Hz, CH3, 6 H),
0.99 (s, CH3, 9 H). 13C NMR (125 MHz, DMSO-d6): δ 142.7, 140.0,
123.4, 121.6, 69.3, 42.8, 35.3, 27.4, 26.9, 24.1, 24.0. HRMS: calcd for
C18H30N2O [M + H]+ 277.2638, found 277.2641. The stereochemical
integrity of the product was not investigated.
(2R)-N′-[(1S)-1-(1-Adamantyl)ethyl]-N-(2,6-diisopropyl-
phenyl)-3,3-dimethylbutane-1,2-diamine (13a) and (2R)-N′-
[(1R)-1-(1-Adamantyl)ethyl]-N-(2,6-diisopropylphenyl)-3,3-di-
methylbutane-1,2-diamine (13b). These compounds were pre-
pared following the synthetic procedure described for 8a starting from
1.03 g of 1-(1-adamantyl)ethanone (5.77 mmol) and 1.45 g of 11
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(5.24 mmol). The reaction time for the first step was 3.5 h and for the
second step was 2 h. 13a,b were collected as a diastereomeric mixture
(695 mg, 0.64 mmol, 30.2%). Diastereomers were separated via
column chromatography using heptane and EtOAc as eluents. The
earlier eluting diastereoisomer was collected as 13a and the later
eluting diastereoisomer as 13b.
13a was collected as a colorless oil (483 mg, 1.10 mmol, 21.0%).
1H NMR (500 MHz, DMSO-d6): δ 7.01 (d, J = 7.6 Hz, Ar-H, 2 H),
6.86 (t, J = 7.6 Hz, Ar-H, 1 H), 3.30 (sp, J = 6.8 Hz, CH, 2 H), 3.02
(m, CH, 1 H), 2.84/2.24 (m+m, CH2, 2 H), 1.81−1.14 (m, CH/
CH2, 15 H), 1.70 (q, J = 6.4 Hz, 1 H), 1.19/1.18 (d+d, J = 6.8 Hz, J =
6.8 Hz, CH3, 12 H), 1.01 (s, CH3, 9 H), 0.66 (d, J = 6.4 Hz, CH3, 3
H). 13C NMR (125 MHz, DMSO-d6): δ 142.3, 139.8, 123.5, 121.7,
67.3, 62.2, 50.1, 37.8, 37.6, 37.0, 36.8, 35.3, 35.2, 27.8, 27.8, 27.2,
27.1, 24.0, 12.9. HRMS: calcd for C30H51N2 [M + H]+ 439.4047,
found 439.4037.
11.4 Hz, NH, 1 H), 3.35 (sp, J = 6.8 Hz, CH, 2 H), 3.01 (m, CH, 1
H), 2.39/2.35 (m+m, CH2, 2 H), 1.32 (br s, NH, 1 H), 1.16 (d, J =
6.8 Hz, CH3, 6 H), 1.12 (d, J = 6.8 Hz, CH3, 6 H), 1.00 (d, J = 6.5 Hz,
CH3, 3 H), 0.94 (s, CH3, 9 H). 13C NMR (125 MHz, DMSO-d6): δ
145.9, 142.6, 139.9, 128.1, 126.4, 126.2, 123.4, 121.8, 66.0, 57.2, 48.4,
35.2, 27.2, 27.0, 24.4, 24.0, 23.9. HRMS: calcd for C26H41N2 [M +
H]+ 381.3264, found 381.3257.
(2R)-N-(2,6-Diisopropylphenyl)-3,3-dimethyl-N′-[(1S)-1-(1-
naphthyl)ethyl]butane-1,2-diamine (13f). This compound was
prepared following the synthetic procedure described for 8a starting
from 0.55 mL of (1S)-1-(1-naphthyl)ethanamine (3.40 mmol) and
850 mg of 5a (3.086 mmol). The reaction time for the first step was 1
h and for the second step was 4 h. 8c and 13f were collected as a
diastereomeric mixture (620 mg, 1.44 mmol, 46.6%). Diastereomers
were separated via column chromatography using heptane and EtOAc
as eluents. The later eluting diastereoisomer, 13f, was collected as a
yellow oil (327 mg, 0.76 mmol, 24.6%). 1H NMR (500 MHz, DMSO-
d6): δ 8.10−7.27 (m, Ar-H, 7 H), 7.01 (d, J = 7.6 Hz, Ar-H, 2 H),
6.90 (t, J = 7.6 Hz, Ar-H, 1 H), 4.20 (q, J = 6.4 Hz, CH, 1 H), 3.39
(sp, J = 6.7 Hz, CH, 2 H), 3.34 (br d, NH, 1 H), 3.08 (m, CH, 1 H),
2.61/2.46 (m+m, CH2, 2 H), 1.17 (d, J = 6.7 Hz, CH3, 6 H), 1.14 (d,
J = 6.4 Hz, CH3, 3 H), 1.10 (d, J = 6.7 Hz, CH3, 6 H), 0.92 (s, CH3, 9
H). 13C NMR (125 MHz, DMSO-d6): δ 142.5, 141.3, 140.1, 133.5,
130.7, 128.6, 126.7, 125.6, 125.6, 125.2, 123.5, 123.0, 122.5, 121.9,
67.4, 54.0, 49.5, 27.1, 27.0, 24.1, 24.0, 23.8. HRMS: calcd for
C30H42N2 [M + H]+ 431.3420, found 431.3411.
13b was collected as a yellowish oil (194 mg, 0.44 mmol, 8.4%). 1H
NMR (500 MHz, DMSO-d6): δ 7.00 (d, J = 7.7 Hz, Ar-H, 2 H), 6.85
(t, J = 7.7 Hz, Ar-H, 1 H), 3.36 (sp, J = 6.8 Hz, CH, 2 H), 3.07 (m,
CH, 1 H), 2.75/2.48 (m+m, CH2, 2 H), 1.84−1.10 (m, CH/CH2, 15
H), 1.73 (q, J = 6.4 Hz, CH, 1 H), 1.19/1.18 (d+d, J = 6.8 Hz, J = 6.8
Hz, CH3, 12 H), 0.99 (s, CH3, 9 H), 0.66 (d, J = 6.4 Hz, CH3, 3 H).
13C NMR (125 MHz, DMSO-d6): δ 143.0, 130.5, 129.1, 121.5, 67.4,
61.7, 51.0, 37.9, 36.9, 27.9, 27.2, 27.1, 24.1, 20.8, 12.9. HRMS: calcd
for C30H51N2 [M + H]+ 439.4047, found 439.4047.
(2R)-N-(2,6-Diisopropylphenyl)-N′-[(1R)-1,2-diphenylethyl]-
3,3-dimethylbutane-1,2-diamine (13c) and (2R)-N-(2,6-Diiso-
propylphenyl)-N′-[(1S)-1,2-diphenylethyl]-3,3-dimethylbu-
tane-1,2-diamine (13d). These compounds were prepared
following the synthetic procedure described for 8a starting from
1.70 g of 11 (6.15 mmol) and 1.11 mL of 1,2-diphenylethanone (6.76
mmol). The reaction time for the first step was 5 h and for the second
step was 2 h. 13c,d were collected as a diastereomeric mixture (950
mg, 0.21 mmol, 33.8%). Diastereomers were separated via column
chromatography using heptane and EtOAc as eluents. The earlier
eluting diastereoisomer was collected as 13c and the later eluting
diastereoisomer as 13d.
(2S)-N-(2-tert-Butylphenyl)-3,3-dimethyl-N′-[(1S)-1-
phenylethyl]butane-1,2-diamine (8i) and (2R)-N-(2-tert-Butyl-
phenyl)-3,3-dimethyl-N′-[(1S)-1-phenylethyl]butane-1,2-dia-
mine (13g). These compounds were prepared following the synthetic
procedure described for 8a starting from 2.35 g of crude 5d (4.75
mmol) and 0.67 mL of (1S)-1-phenylethanamine (5.22 mmol). The
reaction time for the first step was 20 h and for the second step was 2
h. 8i and 13g were collected as a diastereomeric mixture (605 mg,
1.72 mmol, 38.1%). Diastereomers were separated via column
chromatography using heptane and EtOAc as eluents. The earlier
eluting diastereoisomer was collected as 8i and the later eluting
diastereoisomer as 13g.
1
13c was collected as a yellow oil (507 mg, 1.11 mmol, 18.1%). H
1
8i was collected as a yellow oil (317 mg, 0.90 mmol, 18.9%). H
NMR (500 MHz, DMSO-d6): δ 7.25−6.83 (m, Ar-H, 13 H), 3.43
(dd, J = 7.9, 6.0 Hz, CH, 1 H), 3.22 (sp, J = 6.7 Hz, CH, 2 H), 3.10
(d, J = 11.6 Hz, NH, 1 H), 2.81 (m, CH, 1 H), 2.62/2.56 (dd+dd, J =
13.4, 6.0 Hz, J = 13.4, 6.0 Hz, CH2, 2 H), 2.45/2.17 (dm+dd, J = 12.6
Hz, J = 12.6, 5.0 Hz, CH2, 2 H), 1.40 (br s, NH, 1 H), 1.14 (d, J = 6.7
Hz, CH3, 6 H) 1.03 (d, J = 6.7 Hz, CH3, 6 H), 0.82 (s, CH3, 9 H).
13C NMR (125 MHz, DMSO-d6): δ 144.0, 142.1, 140.4, 138.6, 129.0,
128.0, 127.9, 127.0, 126.5, 126.0, 123.4, 122.1, 67.1, 63.9, 47.7, 44.5,
27.0, 26.9, 24.0, 23.8. HRMS: calcd for C32H45N2 [M + H]+
457.3577, found 457.3566.
NMR (400 MHz, DMSO-d6): δ 7.33−7.14 (m, Ar-H, 5 H), 7.11 (dd,
J = 7.7, 1.4 Hz, Ar-H, 1 H), 6.98 (td, J = 7.7, 1.4 Hz, Ar-H, 1 H), 6.77
(d, J = 7.7 Hz, Ar-H, 1 H), 6.50 (td, J = 7.7, 1.4 Hz, Ar-H, 1 H), 3.89
(d, J = 9.0 Hz, NH, 1 H), 3.63 (q, J = 6.6 Hz, CH, 1 H), 3.43 (td, J =
8.0, 3.8 Hz, CH, 1 H), 2.66/2.45 (dd+dd, J = 11.8, 3.8 Hz, J = 11.8,
8.0 Hz, CH2, 2 H), 1.38 (s, CH3, 9 H), 1.15 (d, J = 6.6 Hz, CH3, 3
H), 0.90 (s, CH3, 9 H). 13C NMR (100 MHz, DMSO-d6): δ 146.6,
146.0, 131.5, 128.1, 126.8, 126.5, 126.4, 126.0, 115.3, 111.1, 60.2,
58.0, 48.8, 35.3, 33.7, 29.8, 27.7, 27.1, 24.3. HRMS: calcd for
C24H36N2 [M + H]+ 353.2951, found 353.2962.
13d was collected as a yellow oil (411 mg, 0.90 mmol, 14.6%). 1H
NMR (500 MHz, DMSO-d6): δ 7.20−6.85 (m, Ar-H, 13 H), 3.56 (t, J
= 7.0 Hz, CH, 1 H), 3.25 (sp, J = 6.8 Hz, CH, 2 H), 3.21 (d, J = 11.7
Hz, NH, 1 H), 2.91 (m, CH, 1 H), 2.65/2.56 (dd+dd, J = 13.2, 7.0
Hz, J = 13.2, 7.0 Hz, CH2, 2 H), 2.34 (d, J = 4.4 Hz, CH2, 2 H), 1.35
(br s, NH, 1 H), 1.14 (d, J = 6.8 Hz, CH3, 6 H) 1.07 (d, J = 6.8 Hz,
CH3, 6 H), 0.87 (s, CH3, 9 H). 13C NMR (125 MHz, DMSO-d6): δ
143.3, 142.4, 140.1, 138.7, 129.2, 127.9, 126.9, 126.5, 125.9, 123.4,
121.9, 66.4, 63.9, 48.3, 44.3, 27.0, 27.0, 24.0, 23.8. HRMS: calcd for
C32H45N2 [M + H]+ 457.3577, found 457.3562.
(2R)-N-(2,6-Diisopropylphenyl)-3,3-dimethyl-N′-[(1S)-1-
phenylethyl]butane-1,2-diamine (13e). This compound was
prepared following the synthetic procedure described for 8a starting
from 0.77 mL of (1S)-1-phenylethanamine (6.00 mmol) and 1.50 g of
5a (5.45 mmol). The reaction time for the first step was 2.5 h and for
the second step was 4 h. 8a and 13e were collected as a
diastereomeric mixture (1.75 g, 4.60 mmol, 84.4%). Diastereomers
were separated via column chromatography using heptane and EtOAc
as eluents. The later eluting diastereoisomer, 13e, was collected as a
yellow oil (832 mg, 2.19 mmol, 40.2%). 1H NMR (500 MHz, DMSO-
d6): δ 7.25−7.04 (m, Ar-H, 5 H) 7.00 (d, J = 7.6 Hz, Ar-H, 2 H), 6.89
(t, J = 7.6 Hz, Ar-H, 1 H), 3.44 (q, J = 6.5 Hz, CH, 1 H), 3.35 (d, J =
13g was collected as a yellow oil (249 mg, 0.71 mmol, 14.9%). 1H
NMR (500 MHz, DMSO-d6): δ 7.30−7.15 (m, Ar-H, 5 H), 7.10 (dd,
J = 7.7, 1.4 Hz, Ar-H, 1 H), 6.98 (td, J = 7.7, 1.4 Hz, Ar-H, 1 H), 6.77
(d, J = 7.7 Hz, Ar-H, 1 H), 6.48 (td, J = 7.7, 1.4 Hz, Ar-H, 1 H), 4.02
(d, J = 8.9 Hz, NH, 1 H), 3.58 (q, J = 6.7 Hz, CH, 1 H), 3.47 (m, CH,
1 H), 2.61/2.38 (dd+dd, J = 12.1, 2.5 Hz, J = 12.1, 7.1 Hz, CH2, 2 H),
1.68 (br, NH, 1 H), 1.39 (s, CH3, 9 H), 1.14 (d, J = 6. Hz, CH3, 3 H),
0.90 (s, CH3, 9 H). 13C NMR (125 MHz, DMSO-d6): δ 146.6, 145.9,
131.5, 128.2, 126.8, 126.6, 126.4, 126.0, 115.3, 110.8, 59.1, 57.8, 48.2,
35.5, 33.8, 29.8, 27.1, 24.4. HRMS: calcd for C24H36N2 [M + H]+
353.2951, found 353.2968.
(4R)-1-[(1S)-1-(1-Adamantyl)ethyl]-4-tert-butyl-3-(2,6-diiso-
propylphenyl)-4,5-dihydroimidazolium Chloride (14a). This
compound was prepared following the synthetic procedure described
for 9a starting from 800 mg of 13a (1.82 mmol). 14a was collected as
a yellowish white solid (216 mg, 0.445 mmol, 24.4%). Mp: 120−140
°C. 1H NMR (500 MHz, DMSO-d6): δ 8.82 (s, CH, 1 H), 7.47 (t, J =
7.7 Hz, Ar-H, 1 H), 7.36 (dm, J = 7.7 Hz, Ar-H, 1 H), 7.36 (dm, J =
7.7 Hz, Ar-H, 1 H), 4.48 (dd, J = 12.0, 9.6 Hz, CH, 1 H), 4.42/4.04 (t
+dd, J = 12.0 Hz, J = 12.0, 9.6 Hz, CH2, 2 H), 3.57 (q, J = 7.1 Hz,
CH, 1 H), 3.28 (sp, J = 6.9 Hz, CH, 1 H), 2.99 (sp, J = 6.9 Hz, CH, 1
K
https://dx.doi.org/10.1021/acs.organomet.0c00530
Organometallics XXXX, XXX, XXX−XXX

Organometallics
pubs.acs.org/Organometallics
Article
H), 2.00 (br s., CH, 3 H), 1.71/1.64 (m+m, CH2, 6 H), 1.64/1.51 (m
+m, CH2, 6 H), 1.36 (d, J = 6.8 Hz, CH3, 3 H), 1.33 (d, J = 7.1 Hz,
CH3, 3 H), 1.30 (d, J = 6.8 Hz, CH3, 3 H), 1.20 (d, J = 6.7 Hz, CH3, 3
H), 1.10 (d, J = 6.7 Hz, CH3, 3 H), 0.81 (s, CH3, 9 H). 13C NMR
(125 MHz, DMSO-d6): δ 162.9, 160.4, 145.8, 145.6, 132.0, 130.4,
125.5, 125.2, 74.1, 63.3, 50.1, 38.1, 36.1, 36.0, 34.7, 28.4, 27.9, 27.8,
25.9, 25.7, 25.2, 23.2, 22.5, 11.5. HRMS: calcd for C31H49N2 [M −
Cl−]+ 449.3896, found 449.3874.
(4R)-1-[(1R)-1-(1-Adamantyl)ethyl]-4-tert-butyl-3-(2,6-diiso-
propylphenyl)-4,5-dihydroimidazolium Chloride (14b). This
compound was prepared following the synthetic procedure described
for 9a starting from 485 mg of 13b (1.11 mmol). 14b was collected as
a yellowish white solid (114 mg, 0.235 mmol, 21.3%). Mp: 173-175
°C. 1H NMR (500 MHz, DMSO-d6): δ 8.89 (s, 1 H), 7.49 (t, J = 7.8
Hz, Ar-H, 1 H), 7.38 (m, Ar-H, 1 H), 7.38 (m, Ar-H, 1 H), 4.56 (t, J
= 11.6 Hz, CH, 1 H), 4.44/4.04 (t+t, J = 11.6 Hz, CH, J = 11.6 Hz,
CH2, 2 H), 3.51 (q, J = 7.2 Hz, CH, 1 H), 3.20 (sp, J = 6.8 Hz, CH, 1
H), 2.99 (sp, J = 6.7 Hz, CH, 1 H), 2.02 (br s, CH, 3 H), 1.72/1.61
(m+m, CH2, 6 H), 1.56 (m, CH2, 6 H), 1.35 (d, J = 6.8 Hz, CH3, 3
H), 1.33 (d, J = 7.3 Hz, CH3, 3 H), 1.31 (d, J = 6.8 Hz, CH3, 3 H),
1.19 (d, J = 6.8 Hz, CH3, 3 H), 1.14 (d, J = 6.8 Hz, CH3, 3 H), 0.83
(s, CH3, 9 H). 13C NMR (125 MHz, DMSO-d6): δ 162.9, 160.2,
145.8, 145.5, 131.9, 130.5, 125.5, 125.2, 73.8, 63.3, 51.8, 38.2, 37.8,
36.4, 36.2, 36.1, 34.6, 29.2, 28.7, 28.2, 28.2, 27.7, 27.5, 25.9, 25.4,
25.3, 23.1, 22.6, 21, 12.0. HRMS: calcd for C31H49N2 [M − Cl−]+
449.3896, found 449.3880.
H), 4.37 (dd, J = 12.1, 8.8 Hz, CH, 1 H), 4.07/3.93 (t+dd, J = 12.1
Hz, J = 12.1, 8.8 Hz, CH2, 2 H), 3.23 (sp, J = 6.8 Hz, CH, 1 H), 2.83
(sp, J = 6.8 Hz, CH, 1 H), 1.76 (d, J = 7.0 Hz, CH3, 3 H), 1.30 (d, J =
6.8 Hz, CH3, 3 H), 1.29 (d, J = 6.8 Hz, CH3, 3 H), 1.23 (d, J = 6.8 Hz,
CH3, 3 H), 1.11 (d, J = 6.8 Hz, CH3, 3 H), 0.76 (s, CH3, 9 H). 13C
NMR (125 MHz, DMSO-d6): δ 159.2, 145.5, 145.3, 137.7, 132.1,
130.3, 129.1, 128.8, 126.9, 125.4, 125.3, 74.1, 57, 47.8, 35.1, 28.3, 28,
26, 25.4, 25.2, 23.2, 22.6, 17.7. HRMS: calcd for C27H39N2 [M −
Cl−]+ 391.3108, found 391.3113.
(4R)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1S)-1-(1-
naphthyl)ethyl]-4,5-dihydroimidazolium Chloride (14f). This
compound was prepared following the synthetic procedure described
for 9a starting from 327 mg of 13f (0.759 mmol). 14f was collected as
1
a white solid (232 mg, 0.488 mmol, 64.3%). Mp: 270−272 °C. H
NMR (500 MHz, DMSO-d6): δ 9.21 (s, CH, 1 H), 8.21 (d, J = 8.2
Hz, Ar-H, 1 H), 8.14−7.55 (m, Ar-H, 6 H), 7.79 (d, J = 7.0 Hz, Ar-H,
1 H), 7.48 (t, J = 7.8 Hz, Ar-H, 1 H), 7.38 (m, Ar-H, 2 H), 6.01 (q, J
= 7.0 Hz, CH, 1 H), 4.42 (dd, J = 12.4, 8.7 Hz, CH, 1 H), 4.25/3.75
(t+dd, J = 12.4 Hz, J = 12.4, 8.7 Hz, CH2, 2 H), 3.14 (sp, J = 6.8 Hz,
CH, 1 H), 2.96 (sp, J = 6.8 Hz, CH, 1 H), 1.88 (d, J = 7.0 Hz, CH3, 3
H), 1.32 (d, J = 6.8 Hz, CH3, 3 H), 1.26 (d, J = 6.8 Hz, CH3, 3 H),
1.25 (d, J = 6.8 Hz, CH3, 3 H), 1.17 (d, J = 6.8 Hz, CH3, 3 H), 0.59
(s, CH3, 9 H). 13C NMR (125 MHz, DMSO-d6): δ 158.8, 145.5,
145.1, 133.8, 132.9, 132.0, 130.4, 130.2, 129.5, 129.3, 127.0, 126.3,
125.6, 125.5, 125.3, 124.4, 122.3, 73.6, 53.9, 48.9, 34.9, 28.3, 27.9,
25.8, 25.3, 23.2, 22.6, 18.6. HRMS: calcd for C31H41N2 [M − Cl−]+
441.3264, found 441.3253.
(4R)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1R)-1,2-di-
phenylethyl]-4,5-dihydroimidazolium Chloride (14c). This
compound was prepared following the synthetic procedure described
for 9a starting from 507 mg of 13c (1.11 mmol). 14c was collected as
(4R)-4-tert-Butyl-3-(2-tert-butylphenyl)-1-[(1S)-1-phenyleth-
yl]-4,5-dihydroimidazolium Chloride (14g). This compound was
prepared following the synthetic procedure described for 9a starting
from 245 mg of 13g (0.695 mmol). 14g was collected as a light yellow
solid (70 mg, 0.175 mmol, 25.3%). 1H NMR (500 MHz, DMSO-d6):
δ 9.14 (s, CH, 1 H), 7.71 (dd, J = 7.9, 1.5 Hz, Ar-H, 1 H), 7.60 (dd, J
= 7.9, 1.5 Hz, Ar-H, 1 H), 7.54−7.39 (m, Ar-H, 5 H), 7.49 (t, J = 7.9
Hz, Ar-H, 1 H), 7.39 (td, J = 7.9, 1.5 Hz, Ar-H, 1 H), 5.14 (q, J = 7.0
Hz, CH, 1 H), 4.53 (dd, J = 12.4, 6.8 Hz, CH, 1 H), 3.88/3.75 (t+dd,
J = 12.4 Hz, J = 12.4, 6.8 Hz, CH2, 2 H), 1.74 (d, J = 7.0 Hz, CH3, 3
H), 1.38 (s, CH3, 9 H), 0.70 (s, CH3, 9 H). 13C NMR (125 MHz,
DMSO-d6): δ 158.3, 146.5, 137.6, 134.4, 131.6, 130.3, 130.1, 128.9,
128.8, 127.2, 127.1, 73.1, 57.0, 47.6, 36.0, 35.5, 31.8, 25.2, 17.9.
HRMS: calcd for C25H35N2 [M − Cl−]+ 363.2800, found 363.2784.
(1R,2S,5R)-2-Isopropyl-5-methylcyclohexyl 2-Oxoacetate
(17a). A 78.1 g portion of 15a (500 mmol) and 166 mL of
oxaldehydic acid (1500 mmol) with 25 mL of sulfuric acid (500
mmol) were stirred in 1000 mL of diisopropyl ether (DIPE) at reflux
temperature for 3 days, at which point the maximum conversion
(50%) was observed by GC-MS. The reaction mixture was cooled to
room temperature, and it was extracted with NaCl solution. The
organic layers were dried over MgSO4 and filtered. No further
purification was done; 17a was collected (53.1 g, 250 mmol, 50.0%)
in diisopropyl ether solution. MS (EI, 70 eV) m/z (% relative
intensity, [ion]): 55 (48), 71 (100), 81 (97), 95 (90), 109 (18), 123
(46), 138 (27), 155 (1).
(1S,2R,5S)-2-Isopropyl-5-methylcyclohexyl 2-Oxoacetate
(17b). This compound was prepared following the synthetic
procedure described for 17a starting from 78.1 g of 15b (500
mmol). 17b was collected (53.1 g, 250 mmol, 50.0%) in diisopropyl
ether solution. MS (EI, 70 eV) m/z (% relative intensity, [ion]): 55
(48), 71 (100), 81 (97), 95 (90), 109 (18), 123 (46), 138 (27), 155
(1).
(1R,2S,5R)-2-Isopropyl-5-methylcyclohexyl 2-(2,6-
Diisopropylphenyl)iminoacetate (18a). A 52 mL portion of 2,6-
diisopropylaniline (250 mmol) was added to 53.1 g of 17a (250
mmol) in 1000 mL of DIPE, and 0.5 mL of formic acid was also
added. The resulting mixture was stirred at room temperature for 3 h,
at which point complete conversion was observed by GC-MS. The
solvent was completely removed under vacuum. The residue was
purified via column chromatography using heptane and EtOAc as
eluents. 18a was collected as a yellow oil (76.4 g, 206 mmol, 82.2%).
1H NMR (500 MHz, DMSO-d6): δ 7.77 (s, CH, 1 H), 7.22−7.06 (m,
1
a white solid (518 mg, 1.03 mmol, 92.7%). Mp: 268−270 °C. H
NMR (500 MHz, DMSO-d6): δ 9.31 (s, CH, 1 H), 7.60−7.28 (m, Ar-
H, 10 H), 7.46 (t, J = 7.7 Hz, Ar-H, 1 H), 7.34 (dm, J = 7.7 Hz, Ar-H,
1 H), 7.34 (dm, J = 7.7 Hz, Ar-H, 1 H), 5.48 (dd, J = 11.7, 5.3 Hz,
CH, 1 H), 4.21 (m, CH, 1 H), 4.21/3.86 (m+dd, J = 10.3, 5.4 Hz,
CH2, 2 H), 3.61/3.41 (dd+dd, J = 15.1, 11.7 Hz, J = 15.1, 5.3 Hz,
CH2, 2 H), 2.79 (sp, J = 6.7 Hz, CH, 1 H), 2.65 (sp, J = 6.7 Hz, CH, 1
H), 1.25 (d, J = 6.7 Hz, CH3, 3 H), 1.20 (d, J = 6.7 Hz, CH3, 3 H),
1.19 (d, J = 6.7 Hz, CH3, 3 H) 1.06 (d, J = 6.7 Hz, CH3, 3 H), 0.56 (s,
CH3, 9 H). 13C NMR (125 MHz, DMSO-d6): δ 159.0, 145.3, 145.0,
137.3, 136.4, 131.9, 130.4, 129.1, 129.0, 128.8, 128.7, 127.0, 127.0,
125.4, 125.3, 73.7, 62.1, 50.5, 38.1, 28.3, 27.8, 26.0, 25.2, 25.0, 23.2,
22.5. HRMS: calcd for C33H43N2 [M − Cl−]+ 467.3426, found
467.3424.
(4R)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1S)-1,2-di-
phenylethyl]-4,5-dihydroimidazolium Chloride (14d). This
compound was prepared following the synthetic procedure described
for 9a starting from 411 mg of 13d (0.900 mmol). 14d was collected
as a white solid (437 mg, 0.868 mmol, 96.5%). Mp: 277−279 °C. 1H
NMR (500 MHz, DMSO-d6): δ 9.03 (s, CH, 1 H), 7.64−7.32 (m, Ar-
H, 10 H), 7.42 (t, J = 7.8 Hz, Ar-H, 1 H), 7.30 (dm, J = 7.8 Hz, Ar-H,
1 H), 7.30 (dm, J = 7.8 Hz, Ar-H, 1 H), 5.71 (dd, J = 12.0, 4.4 Hz,
CH, 1 H), 4.42 (dd, J = 12.6, 10.3 Hz, CH, 1 H), 4.05/3.80 (dd+t, J =
12.6, 10.3 Hz, J = 12.6 Hz, CH2, 2 H), 3.75/3.41 (dd+dd, J = 14.4,
12.0 Hz, J = 14.4, 4.4 Hz, CH2, 2 H), 2.73 (sp, J = 6.8 Hz, CH, 1 H),
2.42 (sp, J = 6.8 Hz, CH, 1 H), 1.23 (d, J = 6.8 Hz, CH3, 3 H) 1.14
(d, J = 6.8 Hz, CH3, 3 H), 1.05 (d, J = 6.8 Hz, CH3, 3 H) 0.96 (d, J =
6.8 Hz, CH3, 3 H), 0.61 (s, CH3, 9 H). 13C NMR (125 MHz, DMSO-
d6): δ 159.4, 145.4, 145.2, 136.7, 136.0, 131.3, 130.4, 129.2, 129.1,
128.7, 127.7, 127.0, 125.3, 125.2, 73.8, 61.8, 46.5, 34.8, 28.3, 27.6,
26.1, 25.6, 25.2, 22.7, 22.2. HRMS: calcd for C33H43N2 [M − Cl−]+
467.3426, found 467.3422.
(4R)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1S)-1-phe-
nylethyl]-4,5-dihydroimidazolium Chloride (14e). This com-
pound was prepared following the synthetic procedure described for
9a starting from 832 mg of 13e (2.19 mmol). 14e was collected as a
white solid (460 mg, 1.08 mmol, 49.2%). Mp: 170−172 °C. 1H NMR
(500 MHz, DMSO-d6): δ 9.05 (s, CH, 1 H), 7.52−7.40 (m, Ar-H, 5
H), 7.48 (t, J = 7.7 Hz, Ar-H, 1 H), 7.38 (dd, J = 7.7, 1.5 Hz, Ar-H, 1
H), 7.35 (dd, J = 7.7, 1.5 Hz, Ar-H, 1 H), 5.23 (q, J = 7.0 Hz, CH, 1
L
https://dx.doi.org/10.1021/acs.organomet.0c00530
Organometallics XXXX, XXX, XXX−XXX

Organometallics
pubs.acs.org/Organometallics
Article
Ar-H, 3 H), 4.82 (tm, J = 10.9 Hz, CH, 1 H), 2.72 (sp, J = 6.8 Hz,
CH, 2 H), 2.03/1.14 (m+m, CH2, 2 H), 1.87 (spd, J = 7.0, 2.6 Hz,
CH, 1H), 1.67/1.12 (m+m, CH2, 2 H), 1.67/0.92 (m+m, CH2, 2 H),
1.54 (m, CH, 1 H), 1.51 (m, CH, 1 H), 1.10 (d, J = 6.8 Hz, CH3, 6
H), 1.09 (d, J = 6.8 Hz, CH3, 6 H), 0.92 (d, J = 6.6 Hz, CH3, 3 H),
0.88 (d, J = 7.0 Hz, CH3, 3 H), 0.79 (d, J = 7.0 Hz, CH3, 3 H), 13C
NMR (125 MHz, DMSO-d6): δ 162.1, 155.9, 146.7, 135.8, 125.1,
123.1, 75.4, 46.4, 40.3, 33.6, 30.9, 27.4, 26.5, 23.7, 23.2, 23.1, 21.9,
20.2, 16.9. HRMS: calcd for C24H38NO2 [M + H]+ 372.2897, found
372.2883.
(1S,2R,5S)-2-Isopropyl-5-methylcyclohexyl 2-(2,6-
Diisopropylphenyl)iminoacetate (18b). This compound was
prepared following the synthetic procedure described for 18a starting
from 53.1 g of 17b (250 mmol). 18b was collected as a yellow oil
(60.3 g, 162 mmol, 64.9%). 1H NMR (500 MHz, DMSO-d6): δ 7.77
(s, CH, 1 H), 7.19−7.08 (m, Ar-H, 3 H), 4.82 (td, J = 10.8, 4.3 Hz,
CH, 1 H), 2.72 (sp, J = 6.9 Hz, CH, 2 H), 2.03/1.14 (dm+m, J = 10.8
Hz, CH2, 2 H), 1.87 (dsp, J = 7.0, 2.7 Hz, CH, 1H), 1.67/1.12 (m,
CH2, 2 H), 1.67/0.92 (m, CH2, 2 H), 1.54 (m, CH, 1 H), 1.51 (m,
CH, 1 H), 1.10 (d, J = 6.9 Hz, CH3, 6 H), 1.09 (d, J = 6.9 Hz, CH3, 6
H), 0.92 (d, J = 6.6 Hz, CH3, 3 H), 0.88 (d, J = 7.0 Hz, CH3, 3 H),
0.79 (d, J = 7.0 Hz, CH3, 3 H), 13C NMR (125 MHz, DMSO-d6): δ
162.1, 155.9, 146.7, 135.8, 125.1, 123.0, 75.4, 46.4, 40.3, 33.6, 30.9,
27.4, 26.5, 23.2, 23.1, 21.8, 20.2, 16.9. HRMS: calcd for C24H38NO2
[M + H]+ 372.2897, found 372.2901.
starting from 55.0 g of 18b (148 mmol). 19d was collected as a yellow
oil (55.0 g, 116 mmol, 86.5%). Mp: 86−88 °C. 1H NMR (500 MHz,
DMSO-d6): δ 6.98 (m, Ar-H, 2 H), 6.91 (dd, J = 8.5, 6.8 Hz, Ar-H, 1
H), 4.34 (td, J = 10.9, 4.6 Hz, 1 H), 3.87 (d, J = 12.7 Hz, NH, 1 H),
3.55 (d, J = 12.5 Hz, CH, 1 H), 3.31 (sp, J = 6.8 Hz, CH, 2 H), 1.73/
0.84 (m+m, CH2, 2 H), 1.53/0.74 (m+m, CH2, 2 H), 1.42/0.82 (m
+m, CH2, 2 H), 1.33 (m, CH, 1 H), 1.18 (d, J = 6.8 Hz, CH3, 6 H),
1.15 (d, J = 6.8 Hz, CH3, 6 H), 1.09 (s, CH3,9 H), 0.97 (m, CH, 1 H),
0.81 (d, J = 6.7 Hz, CH3, 3 H), 0.60 (m, CH, 1 H), 0.48 (d, J = 6.8
Hz, CH3, 3 H), 0.13 (d, J = 6.8 Hz, CH3, 3 H). 13C NMR (125 MHz,
DMSO-d6): δ 172.3, 153.5, 140.2, 123.4, 122.9, 72.7, 70.1, 46.1, 40.1,
34.0, 33.5, 30.7, 26.8, 26.1, 24.5, 24.1, 23.8, 22.4, 21.9, 20.8, 15.6.
HRMS: calcd for C28H48NO2 [M + H]+ 430.3680, found 430.3675.
(1R,2S,5R)-2-Isopropyl-5-methylcyclohexyl 2-(2-tert-Butyla-
nilino)-3,3-dimethylbutanoate (19e) and (1R,2S,5R)-2-Iso-
propyl-5-methylcyclohexyl 2-(2-tert-Butylanilino)-3,3-dime-
thylbutanoate (19f). These compounds were prepared following
the synthetic procedure described for 19c starting from 26.8 g of 18c
(78.0 mmol). 19e,f were collected as a diastereomer mixture (23.1 g,
57.4 mmol, 73.6%). Diastereomers (ratio 6/4) were separated via
column chromatography using heptane and EtOAc as eluents.
19e was collected as a light yellow oil (15.7 g, 38.4 mmol, 83.5%).
1H NMR (500 MHz, DMSO-d6): δ 7.15 (dd, J = 7.7, 1.4 Hz, Ar-H, 1
H), 6.96 (td, J = 7.7, 1.4 Hz, Ar-H, 1 H), 6.63 (td, J = 7.7, 1.4 Hz, Ar-
H, 1 H), 6.60 (dm, J = 7.7 Hz, Ar-H, 1 H), 4.52 (td, J = 10.8, 4.2 Hz,
CH, 1 H), 4.37 (d, J = 10.7 Hz, NH, 1 H), 3.97 (d, J = 10.7 Hz, CH, 1
H), 1.91 (spd, J = 7.0, 2.7 Hz, CH, 1 H), 1.80/0.28 (m+m, CH2, 2
H), 1.60/0.96 (m+m, CH2, 2 H), 1.60/0.81 (m+m, CH2, 2 H), 1.40
(s, CH3, 9 H), 1.39 (m, CH, 1 H), 1.35 (m, CH, 1 H), 1.08 (s, CH3, 9
H), 0.84 (d, J = 7.0 Hz, CH3, 3 H), 0.82 (d, J = 6.6 Hz, CH3, 3 H),
0.54 (d, J = 7.0 Hz, CH3, 3 H). 13C NMR (125 MHz, DMSO-d6): δ
172.5, 145.1, 133.4, 126.7, 126.0, 117.6, 111.5, 74.3, 64.3, 46.2, 40.3,
34.0, 33.7, 33.6, 30.8, 29.7, 26.7, 25.5, 22.4, 21.9, 20.6, 15.6. HRMS:
calcd for C26H44NO2 [M + H]+ 402.3367, found 402.3372.
(1R,2S,5R)-2-Isopropyl-5-methylcyclohexyl (2E)-2-(2-tert-
Butylphenyl)iminoacetate (18c). This compound was prepared
following the synthetic procedure described for 18a starting from 26.5
g of 17a (125 mmol) and 16 mL of 2-tert-butylaniline (100 mmol).
1
18c was collected as a yellow oil (26.8 g, 78.0 mmol, 62.0%). H
NMR (500 MHz, DMSO-d6): δ 7.83 (s, CH, 1 H), 7.38 (m, Ar-H, 1
H), 7.25 (m, Ar-H, 1 H), 7.25 (m, Ar-H, 1 H), 7.02 (m, Ar-H, 1 H),
4.77 (td, J = 11.0, 4.4 Hz, CH, 1 H), 2.03/1.08 (m+m, CH2, 2 H),
2.00 (spd, J = 7.0, 2.6 Hz, 1 H), 1.67/0.91 (m+m, CH2, 2 H), 1.67/
1.1 (m+m, CH2, 2 H), 1.52 (m, CH, 1 H), 1.48 (m, CH, 1 H), 1.35
(s, CH3, 9 H), 0.91 (d, J = 6.5 Hz, CH3, 3 H), 0.88 (d, J = 7.0 Hz,
CH3, 3 H), 0.75 (d, J = 7.0 Hz, CH3, 3 H). 13C NMR (125 MHz,
DMSO-d6): δ 162.6, 149.9, 147.9, 143.5, 127.9, 127.2, 126.1, 118.9,
74.8, 46.6, 40.3, 35.2, 33.6, 30.8, 30.2, 25.7, 23.0, 21.9, 20.5, 16.3.
HRMS: calcd for C22H34NO2 [M + H]+ 344.2584, found 344.2589.
(1R,2S,5R)-2-Isopropyl-5-methylcyclohexyl (2S)-2-(2,6-Dii-
sopropylanilino)-3,3-dimethylbutanoate (19c). A solution of
55.0 g of 18a (148 mmol) in 740 mL anhydrous THF was cooled to 0
°C under an inert atmosphere, and then 111 mL of tBuMgCl (222
mmol) was added dropwise over 30 min. The resulting mixture was
stirred for 30 min, at which point complete conversion was observed
by GC-MS. The reaction mixture was quenched by the addition of
saturated aqueous NH4Cl solution and then was warmed to room
temperature and extracted with EtOAc. The combined organic layers
were dried over MgSO4, and the volatiles were removed under
reduced pressure. The crude product was purified via column
chromatography using heptane and EtOAc as eluents. The product
was collected as a diastereomeric mixture. This mixture was dissolved
in EtOH·HCl and the solution stirred overnight at room temperature.
The product (19c) was recrystallized from hexane and collected as a
19f was collected as a light yellow oil (6.90 g, 16.9 mmol, 55.1%).
1H NMR (500 MHz, DMSO-d6): δ 7.17 (dd, J = 7.7, 1.4 Hz, Ar-H, 1
H), 7.00 (td, J = 7.7, 1.4 Hz, Ar-H, 1 H), 6.63 (td, J = 7.7, 1.4 Hz, Ar-
H, 1 H), 6.53 (dm, J = 7.7 Hz, Ar-H, 1 H), 4.50 (td, J = 10.9, 4.4 Hz,
CH, 1 H), 4.35 (d, J = 10.6 Hz, NH, 1 H), 3.91 (d, J = 10.6 Hz, CH, 1
H), 1.80/0.89 (m+m, CH2, 2 H), 1.58/0.77 (m+m, CH2, 2 H), 1.49/
0.87 (m+m, CH2, 2 H), 1.40 (s, CH3, 9 H), 1.39 (m, CH, 1 H), 1.13
(m, CH, 1 H), 1.09 (s, CH3, 9 H), 1.02 (spd, J = 6.9, 2.6 Hz, CH, 1
H), 0.83 (d, J = 6.6 Hz, CH3, 3 H), 0.52 (d, J = 6.9 Hz, CH3, 3 H),
0.32 (d, J = 6.9 Hz, CH3, 3 H). 13C NMR (125 MHz, DMSO-d6): δ
171.9, 145.2, 133.0, 126.9, 126.0, 117.6, 111.3, 73.8, 65.4, 46.1, 40.6,
33.7, 33.5, 33.5, 30.8, 29.6, 26.9, 24.1, 21.9, 21.8, 20.8, 15.0. HRMS:
calcd for C26H44NO2 [M + H]+ 402.3367, found 402.3372.
[(4S)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1S)-1-
phenylethyl]imidazolidin-2-ylidene]silver(I) Chloride (20a). A
500 mg portion of 9a (1.17 mmol) was dissolved in 6 mL of DCM,
and 149 mg of Ag2O (0.644 mmol) was added in one portion. The
reaction mixture was stirred at room temperature in the dark for 1 h,
at which point complete conversion was observed by NMR. The
reaction mixture was filtered through a pad of Celite. The volatiles
were removed under reduced pressure and then recrystallized from
DCM/Et2O. 20a was collected as a brownish white solid (364 mg,
0.682 mmol, 58.2%). Mp: 216−218 °C. 1H NMR (500 MHz,
CDCl3): δ 7.49−7.37 (m, Ar-H, 5 H), 7.35 (t, J = 7.7 Hz, Ar-H, 1 H),
7.22 (dd, J = 7.7, 1.0 Hz, Ar-H, 1 H), 7.17 (dd, J = 7.7, 1.0 Hz, Ar-H,
1 H), 5.57 (q, J = 7.1 Hz, CH, 1 H), 4.03 (dd, J = 11.8 Hz, J = 10.3
Hz, CH, 1 H), 3.75/3.16 (t+t, J = 11.8 Hz, J = 10.3 Hz, CH2, 2 H),
3.44 (sp, J = 6.9 Hz, CH, 1 H), 2.76 (sp, J = 6.9 Hz, CH, 1 H), 1.78
(d, J = 7.1 Hz, CH3, 3 H), 1.53 (d, J = 6.9 Hz, CH3, 3 H), 1.36 (d, J =
6.9 Hz, CH3, 3 H), 1.32 (d, J = 6.9 Hz, CH3, 3 H), 1.23 (d, J = 6.9 Hz,
CH3, 3 H), 0.66 (s, CH3, 9 H). 13C NMR (125 MHz, CDCl3): δ
207.1, 146.5, 146.1, 138.2, 137.1, 129.5, 129.1, 128.5, 126.9, 125.5,
125.3, 75.7, 59.3, 46.4, 29.1, 28.3, 27.7, 26.4, 26.2, 23.8, 23.6, 17.5.
HRMS: calcd for C27H38AgClN2 [M]+ 532.1774, found 532.1769.
[(4S)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1R)-1-
phenylethyl]imidazolidin-2-ylidene]silver(I) Chloride (20b).
1
white solid (15.5 g, 36.1 mmol, 34.8%). Mp: 90−92 °C. H NMR
(500 MHz, DMSO-d6): δ 6.99 (m, Ar-H, 2 H), 6.92 (dd, J = 8.3, 6.8
Hz, Ar-H, 1 H), 4.34 (td, J = 10.5, 4.7 Hz, 1 H), 3.88 (d, J = 12.8 Hz,
NH, 1 H), 3.55 (d, J = 12.8 Hz, CH, 1 H), 3.31 (sp, J = 6.8 Hz, CH, 2
H), 1.73/0.84 (m+m, CH2, 2 H), 1.54/0.74 (m+m, CH2, 2 H), 1.43/
0.82 (m+m, CH2, 2 H), 1.34 (m, CH, 1 H), 1.16 (d, J = 6.8 Hz, CH3,
6 H), 1.15 (d, J = 6.8 Hz, CH3, 6 H), 1.10 (s, CH3,9 H), 0.98 (m, CH,
1 H), 0.81 (d, J = 6.7 Hz, CH3, 3 H), 0.59 (m, CH, 1 H), 0.49 (d, J =
6.8 Hz, CH3, 3 H), 0.13 (d, J = 6.8 Hz, CH3, 3 H). 13C NMR (125
MHz, DMSO-d6): δ 162.1, 155.9, 146.7, 135.8, 125.1, 123.1, 75.4,
46.4, 40.3, 33.6, 30.9, 27.4, 26.5, 23.7, 23.2, 23.1, 21.8, 20.2, 16.9.
HRMS: calcd for C28H48NO2 [M + H]+ 430.3680, found 430.3670.
(1S,2R,5S)-2-Isopropyl-5-methylcyclohexyl (2R)-2-(2,6-Dii-
sopropylanilino)-3,3-dimethylbutanoate (19d). This compound
was prepared following the synthetic procedure described for 19c
M
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Article
This complex was prepared following the synthetic procedure
described for 20a starting from 500 mg of 9b (1.17 mmol). 20b
was collected as a brownish white solid (410 mg, 0.768 mmol, 65.6%).
Mp: 200−225 °C. 1H NMR (500 MHz, CDCl3): δ 7.48−7.35 (m, Ar-
H, 5 H), 7.34 (t, J = 7.7 Hz, Ar-H, 1 H), 7.21 (dd, J = 7.7, 1.2 Hz, Ar-
H, 1 H), 7.14 (dd, J = 7.7, 1.2 Hz, Ar-H, 1 H), 5.60 (q, J = 7.1 Hz,
CH, 1 H), 3.91 (dd, J = 11.8, 10.2 Hz, CH, 1 H), 3.50/3.34 (m+t, J =
11.8 Hz, CH2, 2 H), 3.47 (sp, J = 6.8 Hz, CH, 1 H), 2.64 (sp, J = 6.9
Hz, CH, 1 H), 1.74 (d, J = 7.1 Hz, CH3, 3 H), 1.50 (d, J = 6.8 Hz,
CH3, 3 H), 1.32 (d, J = 6.8 Hz, CH3, 3 H), 1.26 (d, J = 6.9 Hz, CH3, 3
H), 1.22 (d, J = 6.9 Hz, CH3, 3 H), 0.77 (s, CH3, 9 H). 13C NMR
(125 MHz, CDCl3): δ 208.1, 146.6, 146.0, 138.3, 137.2, 129.5, 129.1,
128.6, 127.0, 125.6, 125.2, 76.1, 59.3, 46.1, 29.1, 28.2, 27.8, 26.5, 26.2,
23.7, 23.5, 17.1. HRMS: calcd for C27H38AgClN2 [M]+ 532.1774,
found 532.1769.
collected as a white solid (804 mg, 1.57 mmol, 79.6%). Mp: 185−187
°C. 1H NMR (500 MHz, CDCl3): δ 7.32 (t, J = 7.8 Hz, Ar-H, 1 H),
7.18 (dd, J = 7.8, 1.3 Hz, Ar-H, 1 H), 7.13 (dd, J = 7.8, 1.3 Hz, Ar-H,
1 H), 4.18 (q, J = 7.0 Hz, CH, 1 H), 4.02 (t, J = 11.3 Hz, CH, 1 H),
3.79/3.61 (t+t, J = 11.3 Hz, J = 11.3 Hz, CH2, 2 H), 3.40 (sp, J = 6.9
Hz, CH, 1 H), 2.78 (sp, J = 6.8 Hz, CH, 1 H), 1.45 (d, J = 6.9 Hz,
CH3, 3 H), 1.34 (d, J = 7.0 Hz, CH3, 3 H), 1.32 (d, J = 6.9 Hz, CH3, 3
H), 1.29 (d, J = 6.8 Hz, CH3, 3 H), 1.16 (d, J = 6.8 Hz, CH3, 3 H),
1.07 (s, CH3, 9 H), 0.79 (s, CH3, 9 H). 13C NMR (125 MHz,
CDCl3): δ 201.5, 146.6, 146.4, 137.0, 129.4, 125.5, 125.2, 75.8, 66.0,
48.1, 35.2, 34.7, 29.0, 28.1, 28.0, 27.7, 26.7, 26.2, 23.7, 23.5, 13.7.
HRMS: calcd for C25H42AgClN2 [M]+ 512.2087, found 512.2082.
[(4S)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-(2-
isopropylphenyl)imidazolidin-2-ylidene]silver(I) Chloride
(20g). This complex was prepared following the synthetic procedure
described for 20a starting from 500 mg of 9g (1.14 mmol). 20g was
collected as a white solid (374 mg, 0.683 mmol, 60.2%). Mp: 200−
[(4S)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1S)-1-(1-
naphthyl)ethyl]imidazolidin-2-ylidene]silver(I) Chloride (20c).
This complex was prepared following the synthetic procedure
described for 20a starting from 1.50 g of 9c (3.14 mmol). 20c was
collected as an off-white solid (1.37 g, 2.34 mmol, 74.5%). Mp: 199−
1
209 °C. H NMR (500 MHz, CDCl3): δ 7.46−7.20 (m, Ar-H, 4 H),
7.36 (t, J = 7.7 Hz, Ar-H, 1 H), 7.22 (dd, J = 7.7, 1.5 Hz, Ar-H, 1 H),
7.18 (dd, J = 7.7, 1.5 Hz, Ar-H, 1 H), 4.25 (br m, CH, 1 H), 4.13/
3.92 (br m+t, J = 11.2 Hz, CH2, 2 H), 3.51 (sp, J = 6.8 Hz, CH, 1 H),
3.18 (br m, CH, 1 H), 2.93 (sp, J = 6.8 Hz, CH, 1 H), 1.46 (d, J = 6.8
Hz, CH3, 3 H), 1.42 (d, J = 6.8 Hz, CH3, 3 H), 1.36 (d, J = 6.8 Hz,
CH3, 3 H), 1.33 (br d, J = 6.8 Hz, CH3, 6 H), 1.24 (d, J = 6.8 Hz,
CH3, 3 H), 0.88 (s, CH3, 9 H). 13C NMR (125 MHz, CDCl3): δ
208.0, 146.5, 145.9, 138.0, 130.0, 129.6, 128.0, 127.6, 125.6, 125.3,
56.3, 29.4, 28.4, 26.7, 26.2, 23.8, 23.6. HRMS: calcd for
C28H40AgClN2 [M]+ 546.1931, found 546.1955.
1
201 °C. H NMR (500 MHz, CDCl3): δ 8.32−7.49 (m, Ar-H, 7 H),
7.35 (t, J = 6.8 Hz, Ar-H, 1 H), 7.21 (dd, J = 7.7, 1.0 Hz, Ar-H, 1 H),
7.15 (dd, J = 7.7, 1.0 Hz, Ar-H, 1 H), 6.16 (q, J = 6.8 Hz, CH, 1 H),
3.96 (dd, J = 11.9, 10.4 Hz, CH, 1 H), 3.66/2.71 (t+t, J = 11.9 Hz, J =
10.4 Hz, CH2, 2 H), 3.46 (sp, J = 6.7 Hz, CH, 1 H), 2.75 (sp, J = 6.9
Hz, CH, 1 H), 1.96 (d, J = 6.9 Hz, CH3, 3 H), 1.61 (d, J = 6.9 Hz,
CH3, 3 H), 1.34 (d, J = 7.0 Hz, CH3, 3 H), 1.27 (d, J = 6.9 Hz, CH3, 3
H), 1.20 (d, J = 6.7 Hz, CH3, 3 H), 0.40 (s, CH3, 9 H). 13C NMR
(125 MHz, CDCl3): δ 208.2, 146.5, 146.1, 137.0, 134.1, 133.2, 131.4,
129.9, 129.5, 129.3, 126.8, 126.4, 125.5, 125.2, 124.6, 123.6, 75.4,
56.0, 47.1, 29.1, 28.1, 27.7, 26.3, 26.2, 23.7, 23.6, 18.6. HRMS: calcd
for C31H40AgClN2 [M]+ 582.1931, found 582.1925.
[(4S)-4-tert-Butyl-1-(2-tert-butylphenyl)-3-(2,6-
diisopropylphenyl)imidazolidin-2-ylidene]silver(I) Chloride
(20h). This complex was prepared following the synthetic procedure
described for 20a starting from 200 mg of 9h (0.440 mmol). 20h was
collected as a yellow solid (215 mg, 0.383 mmol, 87.1%). Mp: 122−
[(4S)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1R)-1-(1-
naphthyl)ethyl]imidazolidin-2-ylidene]silver(I) Chloride (20d).
This complex was prepared following the synthetic procedure
described for 20a starting from 1.00 g of 9d (2.10 mmol). 20d was
collected as an off-white solid (1.01 mg, 1.73 mmol, 82.7%). Mp:
230−252 °C. 1H NMR (500 MHz, CDCl3): δ 8.29−7.50 (m, Ar-H, 7
H), 7.36 (t, J = 7.7 Hz, Ar-H, 1 H), 7.23 (dd, J = 7.7, 1.1 Hz, Ar-H, 1
H), 7.15 (dd, J = 7.7, 1.0 Hz, Ar-H, 1 H), 6.19 (q, J = 6.8 Hz, CH, 1
H), 3.78 (t, J = 11.2 Hz, CH, 1 H), 3.48 (sp, J = 6.8 Hz, CH, 1 H),
3.40/2.87 (t+t, J = 11.2 Hz, J = 11.2 Hz, CH2, 2 H), 2.59 (sp, J = 6.8
Hz, CH, 1 H), 1.94 (d, J = 6.9 Hz, CH3, 3 H), 1.55 (d, J = 6.8 Hz,
CH3, 3 H), 1.34 (d, J = 6.8 Hz, CH3, 3 H), 1.27 (d, J = 6.7 Hz, CH3, 3
H), 1.15 (d, J = 6.8 Hz, CH3, 3 H), 0.72 (s, CH3, 9 H). 13C NMR
(125 MHz, CDCl3): δ 210.2, 146.6, 146.1, 137.1, 134.1, 132.8, 131.8,
129.9, 129.5, 129.2, 127.3, 126.5, 125.5, 125.3, 125.2, 124.8, 123.4,
76.0, 56.0, 46.5, 28.8, 28.2, 27.8, 26.5, 26.4, 23.7, 23.6, 19.0. HRMS:
calcd for C31H40AgClN2 [M]+ 582.1931 found 582.1925.
[(4S)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1S)-1,2,2-
trimethylpropyl]imidazolidin-2-ylidene]silver(I) Chloride
(20e). This complex was prepared following the synthetic procedure
described for 20a starting from 900 mg of 9e (2.21 mmol). 20e was
collected as a brownish white solid (677 mg, 1.32 mmol, 59.6%). Mp:
198−216 °C. 1H NMR (500 MHz, CDCl3): δ 7.32 (t, J = 7.7 Hz, Ar-
H, 1 H), 7.18 (dd, J = 7.7, 1.3 Hz, Ar-H, 1 H), 7.13 (dd, J = 7.7, 1.3
Hz, Ar-H, 1 H), 4.15 (q, J = 7.0 Hz, CH, 1 H), 4.07 (dd, J = 11.9, 10.7
Hz, CH, 1 H), 3.88/3.63 (t+t, J = 11.9 Hz, J = 10.7 Hz, CH2, 2 H),
3.41 (sp, J = 6.7 Hz, CH, 1 H), 2.69 (sp, J = 6.8 Hz, CH, 1 H), 1.43
(d, J = 6.7 Hz, CH3, 3 H), 1.34 (d, J = 7.0 Hz, CH3, 3 H), 1.33 (d, J =
6.8 Hz, CH3, 3 H), 1.30 (d, J = 6.7 Hz, CH3, 3 H), 1.18 (d, J = 6.8 Hz,
CH3, 3 H), 1.06 (s, CH3, 9 H), 0.81 (s, CH3, 9 H). 13C NMR (125
MHz, CDCl3): δ 201.5, 146.8, 146.0, 137.2, 129.4, 125.4, 125.3, 76.3,
66.2, 48.5, 35.5, 34.9, 29.1, 28.2, 28.0, 27.4, 26.8, 26.2, 23.8, 23.5,
14.0. HRMS: calcd for C25H42AgClN2 [M]+ 512.2087, found
512.2082.
1
124 °C. H NMR (500 MHz, CDCl3): δ 7.60−7.01 (m, Ar-H, 4 H),
7.37/7.36 (t, J = 7.7 Hz, Ar-H, 1 H), 7.23/7.21 (dd, J = 7.7, 1.5 Hz,
Ar-H, 1 H), 7.19/7.18 (dd, J = 7.7, 1.5 Hz, Ar-H, 1 H), 7.08/7.06 (dd,
J = 7.7, 1.5 Hz, Ar-H, 1 H), 4.44−3.69 (m, CH, CH2, 3 H), 3.51/3.49
(sp, J = 6.8 Hz, CH, 1 H), 2.98/2.94 (sp, J = 6.8 Hz, CH, 1 H), 1.53/
1.53 (s, CH3, 9 H), 1.46/1.43 (d, J = 6.8 Hz, CH3, 3 H), 1.40/1.40 (d,
J = 6.8 Hz, CH3, 3 H), 1.36/1.34 (d, J = 6.8 Hz, CH3, 3 H), 1.20/1.20
(d, J = 6.8 Hz, CH3, 3 H), 0.87/0.85 (s, CH3, 9 H). 13C NMR (125
MHz, CDCl3): δ 214.6, 147.0, 146.6, 146.4, 145.9, 145.6, 140.0,
131.5, 131.2, 129.7, 129.6, 129.6, 129.5, 129.3, 128.3, 128.2, 125.6,
125.3, 125.4, 125.3, 76.4, 76.3, 58.1, 58.0, 34.4, 34.3, 32.9, 32.6, 29.8,
29.5, 29.3, 28.4, 27.6, 27.2, 27.0, 26.4, 26.3, 23.9, 23.7, 23.7, 23.3.
HRMS: calcd for C29H42AgClN2 [M]+ 560.2087, found 560.2247.
[(4S)-4-tert-Butyl-3-(2-tert-butylphenyl)-1-[(1S)-1-
phenylethyl]imidazolidin-2-ylidene]silver(I) Chloride (20i).
This complex was prepared following the synthetic procedure
described for 20a starting from 60 mg of 9i (0.150 mmol). 20i was
1
collected as a yellowish white solid (64 mg, 0.127 mmol, 84.1%). H
NMR (500 MHz, CDCl3): δ 7.50 (dd, J = 7.9, 1.5 Hz, Ar-H, 1 H),
7.45−7.33 (m, Ar-H, 5 H), 7.37 (dd, J = 7.9, 1.5 Hz, Ar-H, 1 H), 7.30
(td, J = 7.9, 1.5 Hz, Ar-H, 1 H), 7.21 (td, J = 7.9, 1.5 Hz, Ar-H, 1 H),
5.51 (q, J = 7.1 Hz, CH, 1 H), 4.25 (dd, J = 11.9, 6.0 Hz, CH, 1 H),
3.75/3.15 (t+dd, J = 11.9 Hz, J = 11.9, 6.0 Hz, CH2, 2 H), 1.70 (d, J =
7.1 Hz, CH3, 3 H), 1.43 (s, CH3, 9 H), 0.54 (s, CH3, 9 H). 13C NMR
(125 MHz, CDCl3): δ 204.9, 146.1, 140.0, 138.2, 133.0, 130.2, 129.0,
128.9, 128.6, 127.3, 127.3, 74.3, 74.3, 59.3, 46.7, 46.6, 36.4, 35.6, 32.5,
26, 17.3. HRMS: calcd for C25H34AgClN2 [M]+ 504.1461 found
504.1472.
[(4R)-1-[(1S)-1-(1-Adamantyl)ethyl]-4-tert-butyl-3-(2,6-
diisopropylphenyl)imidazolidin-2-ylidene]silver(I) Chloride
(21a). This complex was prepared following the synthetic procedure
described for 20a starting from 216 mg of 14a (0.445 mmol). 21a was
collected as a pinkish solid (99 mg, 0.167 mmol, 37.6%). Mp: 223−
234 °C. 1H NMR (500 MHz, CDCl3): δ 7.32 (t, J = 7.8 Hz, Ar-H, 1
H), 7.18 (dd, J = 7.8, 1.6 Hz, Ar-H, 1 H), 7.12 (dd, J = 7.8, 1.6 Hz,
Ar-H, 1 H), 4.02 (t, J = 11.4 Hz, CH, 1 H), 3.98 (br., CH, 1 H), 3.78/
3.61 (t+t, J = 11.4 Hz, J = 11.4 Hz, CH2, 2 H), 3.42 (sp, J = 6.8 Hz,
[(4S)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1R)-1,2,2-
trimethylpropyl]imidazolidin-2-ylidene]silver(I) Chloride
(20f). This complex was prepared following the synthetic procedure
described for 20a starting from 800 mg of 9f (1.97 mmol). 20f was
N
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CH, 1 H), 2.82 (sp, J = 6.8 Hz, CH, 1 H), 2.04 (br., CH, 3 H), 1.75/
1.66 (brd+brd, CH2, 6 H), 1.67 (br., CH2, 6 H), 1.44 (d, J = 6.8 Hz,
CH3, 3 H), 1.35 (d, J = 6.8 Hz, CH3, 3 H), 1.29 (d, J = 6.8 Hz, CH3, 3
H), 1.29 (brd, CH3, 3 H), 1.17 (d, J = 6.8 Hz, CH3, 3 H), 0.79 (s,
CH3, 9 H). 13C NMR (125 MHz, CDCl3): δ 210.9, 146.7, 146.5,
129.4, 125.5, 125.2, 75.8, 66.5, 40.1, 36.9, 34.6, 29.1, 28.5, 28.1, 27.7,
26.8, 26.2, 23.7, 23.5. HRMS: calcd for C31H48AgClN2 [M]+
590.2557, found 509.2880.
[(4R)-1-[(1R)-1-(1-Adamantyl)ethyl]-4-tert-butyl-3-(2,6-
diisopropylphenyl)imidazolidin-2-ylidene]silver(I) Chloride
(21b). This complex was prepared following the synthetic procedure
described for 20a starting from 114 mg of 14b (0.235 mmol). 21b
was collected as a brown solid (118 mg, 0.199 mmol, 84.8%). Mp:
110−120 °C. 1H NMR (500 MHz, CDCl3): δ 7.32 (t, J = 7.8 Hz, Ar-
H, 1 H), 7.18 (dd, J = 7.8, 1.6 Hz, Ar-H, 1 H), 7.13 (dd, J = 7.8, 1.6
Hz, Ar-H, 1 H), 4.05 (dd, J = 11.9, 10.5 Hz, CH, 1 H), 3.95 (br., CH,
1 H), 3.89/3.66 (t+t, J = 11.9 Hz, J = 10.5 Hz, CH2, 2 H), 3.43 (sp, J
= 6.8 Hz, CH, 1 H), 2.68 (sp, J = 6.8 Hz, CH, 1 H), 2.06 (br., CH, 3
H), 1.75/1.66 (brd+brd., CH2, 6 H), 1.69/1.62 (br d+br d., CH2, 6
H), 1.44 (d, J = 6.8 Hz, CH3, 3 H), 1.33 (d, J = 6.9 Hz, CH3, 3 H),
1.31 (d, J = 6.8 Hz, CH3, 3 H), 1.31 (d, J = 6.8 Hz, CH3, 3 H), 1.18
(d, J = 6.8 Hz, CH3, 3 H), 0.82 (s, CH3, 9 H). 13C NMR (125 MHz,
CDCl3): δ 210.7, 146.8, 146.0, 137.4, 129.4, 125.4, 125.2, 76.3, 66.9,
49.2, 40.1, 36.9, 32.0, 29.1, 28.5, 28.4, 28.4, 28.2, 26.9, 26.2, 23.8,
23.5, 22.8, 14.3. HRMS: calcd for C31H48AgClN2 [M]+ 590.2557,
found 509. 3245.
H), 3.92 (dd, J = 11.9 Hz, J = 9.9 Hz, CH, 1 H), 3.52/3.36 (m+t, J =
11.9 Hz, CH2, 2 H), 3.48 (sp, J = 6.8 Hz, CH, 1 H), 2.66 (sp, J = 6.8
Hz, CH, 1 H), 1.76 (d, J = 7.1 Hz, CH3, 3 H), 1.52 (d, J = 6.8 Hz,
CH3, 3 H), 1.33 (d, J = 6.8 Hz, CH3, 3 H), 1.28 (d, J = 6.8 Hz, CH3, 3
H), 1.23 (d, J = 6.8 Hz, CH3, 3 H), 0.79 (s, CH3, 9 H). 13C NMR
(125 MHz, CDCl3): δ 207.1, 146.6, 146.0, 138.3, 137.2, 129.5, 129.1,
128.6, 127.0, 125.6, 125.2, 76.2, 59.3, 46.1, 29.1, 28.2, 27.8, 26.5, 26.2,
23.7, 23.5, 17.1. HRMS: calcd for C27H38AgClN2 [M]+ 532.1774,
found 532.1769.
[(4R)-4-tert-Butyl-3-(2-tert-butylphenyl)-1-[(1S)-1-
phenylethyl]imidazolidin-2-ylidene]silver(I) Chloride (21g).
This complex was prepared following the synthetic procedure
described for 20a starting from 70 mg of 14g (0.175 mmol). 21g
was collected as a yellowish white solid (60 mg, 0.119 mmol, 67.6%).
1H NMR (500 MHz, CDCl3): δ 7.50 (dd, J = 7.9, 1.5 Hz, Ar-H, 1 H),
7.42−7.32 (m, Ar-H, 5 H), 7.39 (dd, J = 7.9, 1.5 Hz, Ar-H, 1 H), 7.30
(td, J = 7.9, 1.5 Hz, Ar-H, 1 H), 7.22 (td, J = 7.9, 1.5 Hz, Ar-H, 1 H),
5.55 (q, J = 7.1 Hz, CH, 1 H), 4.19 (dd, J = 11.9, 5.7 Hz, CH, 1 H),
3.47/3.31 (m+t, J = 11.9 Hz, CH2, 2 H), 1.73 (d, J = 7.1 Hz, CH3, 3
H), 1.37 (s, CH3, 9 H), 0.73 (s, CH3, 9 H). 13C NMR (125 MHz,
CDCl3): δ 206.7, 146.1, 140.0, 138.1, 132.9, 130.1, 129.0, 128.9,
128.5, 127.4, 127.1, 74.2, 74.1, 59.2, 46.6, 46.6, 36.4, 35.9, 32.5, 26.1,
17.2. HRMS: calcd for C25H34AgClN2 [M]+ 504.1461 found
504.1473.
[(4S)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1S)-1-
phenylethyl]imidazolidin-2-ylidene]gold(I) Chloride (22a). A
260 mg portion of 20a (0.487 mmol) was dissolved in 2.5 mL of
DCM, and 143 mg of Me2SAuCl (0.487 mmol) was added in one
portion. The reaction mixture was stirred at room temperature in the
dark for 30 min, at which point complete conversion was observed by
NMR. The reaction mixture was filtered through a pad of Celite. The
volatiles were removed under reduced pressure, and the residue was
then recrystallized from DCM/Et2O. 22a was collected as a purplish
solid (259 mg, 0.416 mmol, 85.4%). Mp: 262−264 °C. 1H NMR (500
MHz, CDCl3): δ 7.48−7.34 (m, Ar-H, 5 H), 7.34 (t, J = 7.7 Hz, Ar-H,
1 H), 7.19 (dd, J = 7.7, 1.4 Hz, Ar-H, 1 H), 7.14 (dd, J = 7.7, 1.4 Hz,
Ar-H, 1 H), 6.10 (q, J = 7.0 Hz, CH, 1 H), 3.93 (dd, J = 11.7 Hz, J =
10.5 Hz, CH, 1 H), 3.71/3.08 (t+t, J = 11.7 Hz, J = 10.5 Hz, CH2, 2
H), 3.40 (sp, J = 6.8 Hz, CH, 1 H), 2.71 (sp, J = 6.8 Hz, CH, 1 H),
1.75 (d, J = 7.0 Hz, CH3, 3 H), 1.60 (d, J = 6.8 Hz, CH3, 3 H), 1.34
(d, J = 6.8 Hz, CH3, 3 H), 1.30 (d, J = 6.8 Hz, CH3, 3 H), 1.29 (d, J =
6.8 Hz, CH3, 3 H), 0.64 (s, CH3, 9 H). 13C NMR (125 MHz,
CDCl3): δ 196.6, 147.0, 146.0, 137.9, 136.7, 129.5, 129.0, 128.5,
127.1, 125.4, 125.2, 75.3, 58.2, 45.5, 34.8, 29.2, 28.4, 27.3, 26.3, 26.1,
23.9, 23.7, 16.6. HRMS: calcd for C27H38AuClN2 [M]+ 622.2389,
found 622.2393.
[(4R)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1R)-1,2-
diphenylethyl]imidazolidin-2-ylidene]silver(I) Chloride (21c).
This complex was prepared following the synthetic procedure
described for 20a starting from 200 mg of 14c (0.440 mmol). 21c
was collected as a white solid (215 mg, 0.383 mmol, 87.1%). Mp:
1
200−218 °C. H NMR (500 MHz, CDCl3): δ 7.53−7.25 (m, Ar-H,
10 H), 7.26 (t, J = 7.7 Hz, Ar-H, 1 H), 7.12 (dd, J = 7.7, 1.4 Hz, Ar-H,
1 H), 7.03 (dd, J = 7.7, 1.4 Hz, Ar-H, 1 H), 5.75 (dd, J = 11.8, 4.6 Hz,
CH, 1 H), 3.83 (dd, J = 11.7, 10.3 Hz, CH, 1 H), 3.72/3.17 (t+t, J =
11.7 Hz, J = 10.3 Hz, CH2, 2 H), 3.52/3.40 (dd+dd, J = 14.3, 4.6 Hz,
J = 14.3, 11.8 Hz, CH2, 2 H), 3.30 (sp, J = 6.8 Hz, CH, 1 H), 2.15 (sp,
J = 6.8 Hz, CH, 1 H), 1.44 (d, J = 6.9 Hz, CH3, 3 H), 1.25 (d, J = 6.7
Hz, CH3, 3 H), 1.18 (d, J = 6.9 Hz, CH3, 3 H), 0.85 (d, J = 6.7 Hz,
CH3, 3 H), 0.56 (s, CH3, 9 H). 13C NMR (125 MHz, CDCl3): δ
209.9, 146.4, 146.1, 137.6, 136.7, 129.3, 129.2, 129.0, 128.8, 127.5,
127.1, 125.3, 125.2, 75.2, 64.8, 46.9, 36.6, 34.7, 28.7, 28.2, 26.6, 26.4,
23.8, 23.5. HRMS: calcd for C33H42AgClN2 [M]+ 608.2087, found
608.2330.
[(4R)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1S)-1,2-
diphenylethyl]imidazolidin-2-ylidene]silver(I) Chloride (21d).
This complex was prepared following the synthetic procedure
described for 20a starting from 143 mg of 14d (0.284 mmol). 21d
was collected as an off-white solid (94 mg, 0.154 mmol, 54.2%). Mp:
[(4S)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1R)-1-
phenylethyl]imidazolidin-2-ylidene]gold(I) Chloride (22b).
This complex was prepared following the synthetic procedure
described for 22a starting from 260 mg of 20b (0.487 mmol). 22b
was collected as a brownish white solid (250 mg, 0.401 mmol, 82.4%).
Mp: 238−240 °C. 1H NMR (500 MHz, CDCl3): δ 7.52−7.36 (m, Ar-
H, 5 H), 7.34 (t, J = 7.7 Hz, Ar-H, 1 H), 7.20 (dd, J = 7.7, 1.4 Hz, Ar-
H, 1 H), 7.13 (dd, J = 7.7, 1.4 Hz, Ar-H, 1 H), 6.15 (q, J = 7.1 Hz,
CH, 1 H), 3.81 (dd, J = 11.8, 10.3 Hz, CH, 1 H), 3.48/3.30 (t+t, J =
10.3 Hz, J = 11.8 Hz, CH2, 2 H), 3.46 (sp, J = 6.8 Hz, CH, 1 H), 2.60
(sp, J = 6.8 Hz, CH, 1 H), 1.73 (d, J = 7.1 Hz, CH3, 3 H), 1.58 (d, J =
6.8 Hz, CH3, 3 H), 1.32 (d, J = 6.8 Hz, CH3, 3 H), 1.30 (d, J = 6.8 Hz,
CH3, 3 H), 1.25 (d, J = 6.8 Hz, CH3, 3 H), 0.78 (s, CH3, 9 H). 13C
NMR (125 MHz, CDCl3): δ 196.4, 147.0, 145.9, 138.2, 137.0, 129.5,
129.0, 128.5, 127.1, 125.5, 125.2, 75.7, 58.0, 45.4, 34.9, 29.2, 28.4,
27.3, 26.5, 26.0, 23.8, 23.6, 16.2. HRMS: calcd for C27H38AuClN2
[M]+ 622.2389, found 622.2399.
1
220−231 °C. H NMR (500 MHz, CDCl3): δ 7.56−7.29 (m, Ar-H,
10 H), 7.26 (t, J = 7.7 Hz, Ar-H, 1 H), 7.09 (dd, J = 7.7, 1.4 Hz, Ar-H,
1 H), 7.06 (dd, J = 7.7, 1.4 Hz, Ar-H, 1 H), 5.78 (dd, J = 12.1, 4.1 Hz,
CH, 1 H), 3.90 (t, J = 11.5 Hz, CH, 1 H), 3.51/3.34 (dd+dd, J = 14.3,
4.1 Hz, J = 14.3, 12.1 Hz, CH2, 2 H), 3.45/3.30 (t+t, J = 11.5 Hz, J =
11.5 Hz, CH2, 2 H), 2.73 (sp, J = 6.8 Hz, CH, 1 H), 2.59 (sp, J = 6.8
Hz, CH, 1 H), 1.23 (d, J = 6.8 Hz, CH3, 3 H), 1.18 (d, J = 6.8 Hz,
CH3, 3 H), 1.17 (d, J = 6.8 Hz, CH3, 3 H), 1.16 (d, J = 6.8 Hz, CH3, 3
H), 0.65 (s, CH3, 3 H). 13C NMR (125 MHz, CDCl3): δ 209.4,
146.7, 145.9, 137.6, 136.5, 129.6, 129.4, 129.3, 129.2, 128.8, 127.4,
127.3, 125.4, 125.0, 76.0, 65.1, 46.2, 36.1, 29.0, 27.8, 27.6, 26.9, 26.2,
23.5, 23.5. HRMS: calcd for C33H42AgClN2 [M]+ 608.2087, found
608.2404.
[(4R)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1S)-1-
phenylethyl]imidazolidin-2-ylidene]silver(I) Chloride (21e).
This complex was prepared following the synthetic procedure
described for 20a starting from 300 mg 14e (0.702 mmol). 21e
was collected as an off-white solid (250 mg, 0.468 mmol, 66.8%). Mp:
220−222 °C. 1H NMR (500 MHz, CDCl3): δ 7.49−7.37 (m, Ar-H, 5
H), 7.35 (t, J = 7.8 Hz, Ar-H, 1 H), 7.22 (dd, J = 7.8, 1.1 Hz, Ar-H, 1
H), 7.15 (dd, J = 7.8, 1.1 Hz, Ar-H, 1 H), 5.62 (q, J = 7.1 Hz, CH, 1
[(4S)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1S)-1-(1-
naphthyl)ethyl]imidazolidin-2-ylidene]gold(I) Chloride (22c).
This complex was prepared following the synthetic procedure
described for 22a starting from 260 mg of 20c (0.445 mmol). 22c
was collected as an off-white solid solid (152 mg, 0.226 mmol,
1
50.7%). Mp: 246−250 °C. H NMR (500 MHz, CDCl3): δ 8.50−
7.48 (m, Ar-H, 7 H), 7.35 (t, J = 7.8 Hz, Ar-H, 1 H), 7.20 (dd, J = 7.8,
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1.5 Hz, Ar-H, 1 H), 7.14 (dd, J = 7.8, 1.5 Hz, Ar-H, 1 H), 6.62 (q, J =
6.8 Hz, CH, 1 H), 3.85 (dd, J = 11.9, 10.2 Hz, CH, 1 H), 3.53/2.48 (t
+dd, J = 11.9 Hz, J = 11.9, 10.2 Hz, CH2, 2 H), 3.42 (sp, J = 6.8 Hz,
CH, 1 H), 2.73 (sp, J = 6.8 Hz, CH, 1 H), 1.94 (d, J = 6.8 Hz, CH3, 3
H), 1.71 (d, J = 6.8 Hz, CH3, 3 H), 1.33 (d, J = 6.8 Hz, CH3, 3 H),
1.32 (d, J = 6.8 Hz, CH3, 3 H), 1.25 (d, J = 6.8 Hz, CH3, 3 H), 0.35
(s, CH3, 9 H). 13C NMR (125 MHz, CDCl3): δ 197.3, 147.0, 146.0,
136.6, 134.0, 133.1, 131.7, 129.8, 129.5, 129.1, 126.9, 126.5, 125.4,
125.1, 125.0, 124.6, 124.0, 74.9, 55.3, 46.1, 29.3, 28.3, 27.3, 26.1, 26.1,
23.8, 23.7, 17.7. HRMS: calcd for C31H40AuClN2 [M]+ 672.2546,
found 672.3098.
[(4S)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1R)-1-(1-
naphthyl)ethyl]imidazolidin-2-ylidene]gold(I) Chloride (22d).
This complex was prepared following the synthetic procedure
described for 22a starting from 50 mg of 20d (0.942 mmol). 22d
was collected as an off-white solid (592 mg, 0.880 mmol, 93.4%). Mp:
296−298 °C. 1H NMR (500 MHz, CDCl3): δ 8.47−7.49 (m, Ar-H, 7
H), 7.35 (t, J = 7.7 Hz, Ar-H, 1 H), 7.21 (dd, J = 7.7, 1.5 Hz, Ar-H, 1
H), 7.12 (dd, J = 7.7, 1.5 Hz, Ar-H, 1 H), 6.62 (q, J = 6.8 Hz, CH, 1
H), 3.67 (t, J = 11.3 Hz, CH, 1 H), 3.46 (sp, J = 6.7 Hz, CH, 1 H),
3.33/2.78 (t+t, J = 11.3 Hz, 11.3 Hz, CH2, 2 H), 2.55 (sp, J = 6.8 Hz,
CH, 1 H), 1.92 (d, J = 6.8 Hz, CH3, 3 H), 1.61 (d, J = 6.7 Hz, CH3, 3
H), 1.35 (d, J = 6.8 Hz, CH3, 3 H), 1.32 (d, J = 6.8 Hz, CH3, 3 H),
1.11 (d, J = 6.7 Hz, CH3, 3 H), 0.70 (s, 9 H). 13C NMR (125 MHz,
CDCl3): δ 197.4, 147.1, 146.0, 134.1, 132.9, 132.0, 127.3, 126.6,
125.4, 125.2, 125.1, 124.9, 123.8, 75.4, 55.2, 45.8, 28.8, 28.4, 27.3,
26.5, 26.3, 23.8, 23.7, 18.0. HRMS: calcd for C31H40AuClN2 [M]+
672.2546, found 672.2554.
[(4S)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1S)-1,2,2-
trimethylpropyl]imidazolidin-2-ylidene]gold(I) Chloride (22e).
This complex was prepared following the synthetic procedure
described for 22a starting from 400 mg of 20e (0.7784 mmol). 22e
was collected as a purplish white solid (427 mg, 0.708 mmol, 91.0%).
Mp: 232−234 °C. 1H NMR (500 MHz, CDCl3): δ 7.33 (t, J = 7.7 Hz,
Ar-H, 1 H), 7.17 (dd, J = 7.7 Hz, J = 1.5 Hz, Ar-H, 1 H), 7.12 (dd, J =
7.7 Hz, J = 1.5 Hz, Ar-H, 1 H), 4.73 (q, J = 7.1 Hz, CH, 1 H), 3.99
(dd, J = 11.9, 10.8 Hz, CH, 1 H), 3.86/3.61 (t+t, J = 11.9 Hz, J = 10.8
Hz, CH2, 2 H), 3.38 (sp, J = 6.8 Hz, CH, 1 H), 2.65 (sp, J = 6.8 Hz,
CH, 1 H), 1.53 (d, J = 6.8 Hz, CH3, 3 H), 1.33 (d, J = 6.8 Hz, CH3, 3
H), 1.33 (d, J = 7.1 Hz, CH3, 3 H), 1.30 (d, J = 6.8 Hz, CH3, 3 H),
1.26 (d, J = 6.8 Hz, CH3, 3 H), 1.08 (s, CH3, 9 H), 0.81 (s, CH3, 9
H). 13C NMR (125 MHz, CDCl3): δ 198.5, 147.2, 145.8, 136.9,
129.4, 125.3, 125.2, 75.9, 64.7, 47.8, 35.3, 29.2, 28.4, 28.0, 27.0, 26.7,
26.0, 23.9, 23.6, 13.5. HRMS: calcd for C25H42AuClN2 [M]+
602.2702, found 602.2697.
CH3,18 H), 0.88/0.87 (s, CH3, 9 H). 13C NMR (125 MHz, CDCl3):
δ 198.8, 147.0, 146.0, 145.8, 145.7, 137.5, 136.5, 130.0, 129.9, 129.7,
129.6, 128.2, 128.0, 127.5, 127.4, 127.4, 125.6, 125.4, 125.3, 125.2,
76.1, 75.8, 56.1, 56.0, 34.8, 29.6, 29.4, 28.6, 28.5, 28.5, 28.4, 27.2,
27.0, 26.6, 24.5, 24.4, 24.1, 23.9, 23.7, 23.6. HRMS: calcd for
C28H40AuClN2 [M]+ 636.2546 found 636.2806.
[(4S)-4-tert-Butyl-1-(2-tert-butylphenyl)-3-(2,6-
diisopropylphenyl)imidazolidin-2-ylidene]gold(I) Chloride
(22h). This complex was prepared following the synthetic procedure
described for 22a starting from 215 mg of 20h (0.383 mmol). 22h
was collected as a yellowish white solid (35 mg, 0.054 mmol, 14.1%).
Mp: 104−125 °C. 1H NMR (500 MHz, CDCl3): δ 7.60−7.08 (m, Ar-
H, 7 H), 4.20 (m, CH, 1 H), 4.20/3.73 (m+m, CH2, 2 H), 3.48 (sp, J
= 6.8 Hz, CH, 1 H), 2.96 (sp, J = 6.8 Hz, CH, 1 H), 1.55 (s, CH3, 9
H), 1.55/1.36 (d+d, J = 6.8 Hz, J = 6.8 Hz, CH3, 6 H), 1.39/1.27 (d
+d, J = 6.8 Hz, J = 6.8 Hz, CH3, 6 H), 0.87/0.85 (s, CH3, 9 H). 13C
NMR (125 MHz, CDCl3): δ 201.0, 147.1, 146.9, 145.7, 139.4, 136.1,
131.3, 129.7, 129.5, 129.4, 128.1, 125.5, 125.2, 75.6, 57.9, 34.3, 32.9,
32.6, 29.7, 29.3, 28.5, 27.2, 26.9, 26.2, 23.8, 23.8. HRMS: calcd for
C29H42AuClN2 [M]+ 650.2702 found 650.2679.
[(4S)-4-tert-Butyl-3-(2-tert-butylphenyl)-1-[(1S)-1-
phenylethyl]imidazolidin-2-ylidene]gold(I) Chloride (22i). This
complex was prepared following the synthetic procedure described for
22a starting from 60 mg of 20i (0.119 mmol). 22i was collected as a
yellowish white solid (28 mg, 0.047 mmol, 39.7%). Mp: 238−240 °C.
1H NMR (500 MHz, CDCl3): δ 7.51−7.32 (m, Ar- H, 5 H), 7.50 (dd,
J = 7.7, 1.5 Hz, Ar-H, 1 H), 7.47 (dd, J = 7.7, 1.5 Hz, Ar-H, 1 H), 7.30
(td, J = 7.7, 1.5 Hz, Ar-H, 1 H), 7.20 (td, J = 7.7, 1.5 Hz, Ar-H, 1 H),
6.07 (q, J = 7.0 Hz, CH, 1 H), 4.25 (dd, J = 11.8, 6.1 Hz, CH, 1 H),
3.73/3.09 (t+dd, J = 11.8 Hz, J = 11.8, 6.1 Hz, CH2, 2 H), 1.69 (d, J =
7.0 Hz, CH3, 3 H), 1.45 (s, CH3, 9 H), 0.53 (s, CH3, 9 H). 13C NMR
(125 MHz, CDCl3): δ 193.8, 146.2, 139, 137.9, 133.9, 130.1, 128.9,
128.6, 127.4, 126.9, 73.7, 58.1, 45.7, 36.5, 35.5, 32.5, 25.9, 16.4.
HRMS: calcd for C25H34AuClN2 [M]+ 594.2076 found 594.2113.
[(4R)-1-[(1S)-1-(1-Adamantyl)ethyl]-4-tert-butyl-3-(2,6-
diisopropylphenyl)imidazolidin-2-ylidene]gold(I) Chloride
(23a). This complex was prepared following the synthetic procedure
described for 22a starting from 90 mg of 21a (0.152 mmol). 23a was
collected as an off-white solid (55 mg, 0.081 mmol, 53.1%). Mp:
260−262 °C. 1H NMR (500 MHz, CDCl3): δ 7.33 (t, J = 7.7 Hz, Ar-
H, 1 H), 7.18 (dd, J = 7.7, 1.5 Hz, Ar-H, 1 H), 7.12 (dd, J = 7.7, 1.5
Hz, Ar-H, 1 H), 4.55 (q, J = 7.1 Hz, CH, 1 H), 3.95 (t, J = 11.5 Hz,
CH, 1 H), 3.77/3.58 (t+t, J = 11.5 Hz, J = 11.5 Hz, CH2, 2 H), 3.42
(sp, J = 6.8 Hz, CH, 1 H), 2.80 (sp, J = 6.8 Hz, CH, 1 H), 2.05 (br t,
CH, 3 H), 1.77/1.66 (br d+br d., CH2, 6 H), 1.75/1.66 (br d+br d,
CH2, 6 H), 1.53 (d, J = 6.8 Hz, CH3, 3 H), 1.34 (d, J = 6.8 Hz, CH3, 3
H), 1.29 (d, J = 6.8 Hz, CH3, 3 H), 1.27 (d, J = 7.1 Hz, CH3, 3 H),
1.24 (d, J = 6.8 Hz, CH3, 3 H), 0.80 (s, CH3, 9 H). 13C NMR (125
MHz, CDCl3): δ 198.5, 147.1, 146.3, 136.7, 129.5, 125.4, 125.1, 75.2,
65.1, 48.6, 40.1, 37.0, 34.4, 29.2, 28.6, 28.3, 27.1, 26.7, 26.0, 23.8,
23.6, 11.8. HRMS: calcd for C31H48AuClN2 [M]+ 680.3172, found
680.3844.
[(4R)-1-[(1R)-1-(1-Adamantyl)ethyl]-4-tert-butyl-3-(2,6-
diisopropylphenyl)imidazolidin-2-ylidene]gold(I) Chloride
(23b). This complex was prepared following the synthetic procedure
described for 22a starting from 110 mg of 21b (0.186 mmol). 23b
was collected as a purple solid (84 mg, 0.123 mmol, 66.4%). Mp:
103−118 °C. 1H NMR (500 MHz, CDCl3): δ 7.32 (t, J = 7.7 Hz, Ar-
H, 1 H), 7.17 (dd, J = 7.7, 1.5 Hz, Ar-H, 1 H), 7.12 (dd, J = 7.7, 1.5
Hz, Ar-H, 1 H), 4.56 (q, J = 6.9 Hz, CH, 1 H), 3.98 (dd, J = 11.8, 10.6
Hz, CH, 1 H), 3.87/3.36 (t+t, J = 11.8 Hz, J = 10.6 Hz, CH2, 2 H),
3.42 (sp, J = 6.8 Hz, CH, 1 H), 2.67 (sp, J = 6.9 Hz, CH, 1 H), 2.12−
1.98 (m, CH, 3 H), 1.85−1.21 (m, CH2, 12 H), 1.53 (d, J = 6.8 Hz,
CH3, 3 H), 1.32 (d, J = 6.9 Hz, CH3, 3 H), 1.31 (d, J = 6.9 Hz, CH3, 3
H), 1.28 (br d, CH3, 3 H), 1.25 (d, J = 6.8 Hz, CH3, 3 H), 0.84 (s,
CH3, 9 H). 13C NMR (125 MHz, CDCl3): δ 198.4, 147.2, 145.8,
137.1, 129.4, 125.3, 125.2, 76.0, 65.5, 48.6, 40.0, 36.9, 31.7, 30.7, 29.2,
28.6, 27.0, 26.8, 26.0, 23.9, 23.6, 22.8, 14.3, 12.1. HRMS: calcd for
C31H48AuClN2 [M]+ 680.3172, found 680.3184.
[(4S)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1R)-1,2,2-
trimethylpropyl]imidazolidin-2-ylidene]gold(I) Chloride (22f).
This complex was prepared following the synthetic procedure
described for 22a starting from 430 mg of 20f (0.837 mmol). 22f
was collected as an off-white white solid (395 mg, 0.655 mmol,
78.3%). Mp: 230−232 °C. 1H NMR (500 MHz, CDCl3): δ 7.33 (t, J
= 7.7 Hz, Ar-H, 1 H), 7.18 (dd, J = 7.7, 1.5 Hz, Ar-H, 1 H), 7.12 (dd,
J = 7.7 Hz, J = 1.5 Hz, Ar-H, 1 H), 4.75 (q, J = 7.0 Hz, CH, 1 H), 3.95
(t, J = 11.3 Hz, CH, 1 H), 3.78/3.59 (t+t, J = 11.3 Hz, J = 11.3 Hz,
CH2, 2 H), 3.40 (sp, J = 6.7 Hz, CH, 1 H), 2.75 (sp, J = 6.8 Hz, CH, 1
H), 1.53 (d, J = 6.8 Hz, CH3, 3 H), 1.34 (d, J = 6.8 Hz, CH3, 3 H),
1.31 (d, J = 7.0 Hz, CH3, 3 H), 1.29 (d, J = 6.7 Hz, CH3, 3 H), 1.23
(d, J = 6.7 Hz, CH3, 3 H), 1.09 (s, CH3, 9 H), 0.80 (s, CH3, 9 H). 13
C
NMR (125 MHz, CDCl3): δ 198.5, 147.1, 146.3, 136.7, 129.5, 125.4,
125.1, 75.3, 64.6, 47.6, 35.1, 29.1, 28.3, 28.0, 27.2, 26.6, 25.9, 23.8,
23.6, 13.2. HRMS: calcd for C25H42AuClN2 [M]+ 602.2702 found
602.2696.
[(4S)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-(2-
isopropylphenyl)imidazolidin-2-ylidene]gold(I) Chloride
(22g). This complex was prepared following the synthetic procedure
described for 22a starting from 364 mg of 20g (0.664 mmol). 22g was
collected as a white solid (250 mg, 0.393 mmol, 59.1%). Mp: 211−
1
213 °C. H NMR (500 MHz, CDCl3): δ 7.46−7.14 (m, Ar-H, 7 H),
4.23/4.17 (m, CH, 1 H), 4.17/3.89 + 4.08/3.89 (m+m, CH2, 2 H),
[(4R)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1R)-1,2-
diphenylethyl]imidazolidin-2-ylidene]gold(I) Chloride (23c).
3.58−2.84 (sp, J = 6.8 Hz, CH, 3 H), 1.61−1.26 (d, J = 6.8 Hz,
P
https://dx.doi.org/10.1021/acs.organomet.0c00530
Organometallics XXXX, XXX, XXX−XXX

Organometallics
pubs.acs.org/Organometallics
Article
This complex was prepared following the synthetic procedure
described for 22a starting from 37 mg of 21c (0.061 mmol). 23c
was collected as a purple solid (40 mg, 0.057 mmol, 94.3%). Mp:
ASSOCIATED CONTENT
* Supporting Information
(PDF) The Supporting Information is available free of charge
at https://pubs.acs.org/doi/10.1021/acs.organomet.0c00530.
■
sı
1
239−241 °C. H NMR (500 MHz, CDCl3): δ 7.63−7.27 (m, Ar-H,
10 H), 7.27 (t, J = 7.7 Hz, Ar-H, 1 H), 7.12 (dd, J = 7.7, 1.4 Hz, Ar-H,
1 H), 7.02 (dd, J = 7.7, 1.4 Hz, Ar-H, 1 H), 6.34 (dd, J = 11.8, 4.9 Hz,
CH, 1 H), 3.69/3.15 (m+m, CH2, 2 H), 3.69 (m, CH, 1 H), 3.54/
3.39 (dd+dd, J = 14.5, 4.9 Hz, J = 14.5, 11.8 Hz, CH2, 2 H), 3.28 (sp,
J = 6.8 Hz, CH, 1 H), 2.02 (sp, J = 6.8 Hz, CH, 1 H), 1.53 (d, J = 6.8
Hz, CH3, 3 H), 1.24 (d, J = 6.8 Hz, CH3, 3 H), 1.14 (d, J = 6.8 Hz,
CH3, 3 H), 0.90 (d, J = 6.8 Hz, CH3, 3 H), 0.59 (s, CH3, 9 H). 13C
NMR (125 MHz, CDCl3): δ 197.4, 146.9, 146.2, 137.3, 136.4, 136.2,
129.4, 129.2, 129.1, 129.1, 128.7, 127.3, 127.2, 125.2, 125.1, 75.0,
63.0, 45.9, 36.1, 34.4, 28.7, 28.3, 27.3, 26.4, 23.8, 23.6. HRMS: calcd
for C33H42AuClN2 [M]+ 698.2702 found 698.3581.
Additional experimental data and NMR spectra of all
compounds (PDF)
Accession Codes
CCDC 2011206−2011210 contain the supplementary crys-
tallographic data for this paper. These data can be obtained
free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by
emailing data_request@ccdc.cam.ac.uk, or by contacting The
Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
[(4R)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1S)-1,2-
diphenylethyl]imidazolidin-2-ylidene]gold(I) Chloride (23d).
This complex was prepared following the synthetic procedure
described for 22a starting from 83 mg of 21d (0.136 mmol). 23d
was collected as a purple solid (75 mg, 0.107 mmol, 78.8%). Mp:
AUTHOR INFORMATION
Corresponding Authors
■
Attila Paczal − Servier Research Institute of Medicinal Chemistry,
H-1031 Budapest, Hungary; Email: attila.paczal@servier.com
Andras Kotschy − Servier Research Institute of Medicinal
Chemistry, H-1031 Budapest, Hungary; orcid.org/0000-
0002-7675-3864; Email: andras.kotschy@servier.com
1
230−232 °C. H NMR (500 MHz, CDCl3): δ 7.60−7.28 (m, Ar-H,
10 H), 7.28 (t, J = 7.7 Hz, Ar-H, 1 H), 7.09 (dd, J = 7.7, 1.5 Hz, Ar-H,
1 H), 7.06 (dd, J = 7.7, 1.5 Hz, Ar-H, 1 H), 6.40 (dd, J = 11.9, 4.7 Hz,
CH, 1 H), 3.82 (t, J = 11.9 Hz, CH, 1 H), 3.56/3.34 (dd+dd, J = 14.4,
4.7 Hz, J = 14.4, 11.9 Hz, CH2, 2 H), 3.41/3.33 (t+m, J = 11.9 Hz,
CH2, 2 H), 2.76 (sp, J = 6.8 Hz, CH, 1 H), 2.56 (sp, J = 6.8 Hz, CH, 1
H), 1.33 (d, J = 6.8 Hz, CH3, 3 H), 1.26 (d, J = 6.8 Hz, CH3, 3 H),
1.22 (d, J = 6.8 Hz, CH3, 3 H), 1.16 (d, J = 6.8 Hz, CH3, 3 H), 0.61
(s, CH3, 9 H). 13C NMR (125 MHz, CDCl3): δ 197.4, 147.1, 145.8,
137.6, 136.2, 136.0, 129.8, 129.5, 129.2, 128.9, 128.7, 127.3, 127.3,
125.2, 125.0, 75.4, 62.7, 45.6, 35.7, 34.3, 29.1, 27.8, 27.3, 26.7, 26.0,
23.7, 23.6. HRMS: calcd for C33H42AuClN2 [M]+ 698.2702 found
698.2736.
Authors
Zita Szabo − Servier Research Institute of Medicinal Chemistry,
H-1031 Budapest, Hungary
Matyas Timari − Servier Research Institute of Medicinal
Chemistry, H-1031 Budapest, Hungary
Rudolf Kassai − Servier Research Institute of Medicinal
Chemistry, H-1031 Budapest, Hungary
Bianka Szokol − Servier Research Institute of Medicinal
Chemistry, H-1031 Budapest, Hungary
[(4R)-4-tert-Butyl-3-(2,6-diisopropylphenyl)-1-[(1S)-1-
phenylethyl]imidazolidin-2-ylidene]gold(I) Chloride (23e).
This complex was prepared following the synthetic procedure
described for 22a starting from 200 mg of 21e (0.395 mmol). 23e
was collected as a yellowish white solid (210 mg, 0.337 mmol, 85.7%).
Mp: 245−247 °C. 1H NMR (500 MHz, CDCl3): δ 7.52−7.36 (m, Ar-
H, 5 H), 7.34 (t, J = 7.7 Hz, Ar-H, 1 H), 7.20 (dd, J = 7.7, 1.4 Hz, Ar-
H, 1 H), 7.13 (dd, J = 7.7, 1.4 Hz, Ar-H, 1 H), 6.14 (q, J = 7.0 Hz,
CH, 1 H), 3.81 (dd, J = 11.8, 10.3 Hz, CH, 1 H), 3.48/3.30 (t+t, J =
10.3 Hz, J = 11.8 Hz, CH2, 2 H), 3.46 (sp, J = 6.8 Hz, CH, 1 H), 2.60
(sp, J = 6.8 Hz, CH, 1 H), 1.73 (d, J = 7.0 Hz, CH3, 3 H), 1.58 (d, J =
6.8 Hz, CH3, 3 H), 1.32 (d, J = 6.8 Hz, CH3, 3 H), 1.30 (d, J = 6.8 Hz,
CH3, 3 H), 1.25 (d, J = 6.8 Hz, CH3, 3 H), 0.78 (s, CH3, 9 H). 13C
NMR (125 MHz, CDCl3): δ 196.4, 147.0, 145.9, 138.2, 137.0, 129.5,
129.0, 128.5, 127.1, 125.5, 125.2, 75.7, 58.0, 45.4, 34.9, 29.2, 28.4,
27.3, 26.5, 26.0, 23.8, 23.6, 16.2. HRMS: calcd for C27H38AuClN2
[M]+ 622.2389, found 622.2390.
[(4R)-4-tert-Butyl-3-(2-tert-butylphenyl)-1-[(1S)-1-
phenylethyl]imidazolidin-2-ylidene]gold(I) Chloride (23g).
This complex was prepared following the synthetic procedure
described for 22a starting from 60 mg of 21g (0.119 mmol). 23g
was collected as a brownish white solid (62 mg, 0.104 mmol, 87.9%).
Mp: 191−198 °C. 1H NMR (500 MHz, CDCl3): δ 7.46−7.31 (m, Ar-
H, 5 H), 7.50 (dd, J = 7.8, 1.5 Hz, Ar-H, 1 H), 7.48 (dd, J = 7.8, 1.5
Hz, Ar-H, 1 H), 7.30 (td, J = 7.8, 1.5 Hz, Ar-H, 1 H), 7.21 (td, J = 7.8,
1.5 Hz, Ar-H, 1 H), 6.10 (q, J = 7.1 Hz, CH, 1 H), 4.10 (dd, J = 11.9,
6.0 Hz, CH, 1 H), 3.43/3.26 (dd+t, J = 11.9, 6.0 Hz, J = 11.9 Hz,
CH2, 2 H), 1.72 (d, J = 7.1 Hz, CH3, 3 H), 1.38 (s, CH3, 9 H), 0.74
(s, CH3, 9 H). 13C NMR (125 MHz, CDCl3): δ 193.8, 146.2, 139,
137.9, 133.9, 130.1, 128.9, 128.5, 127.3, 127, 73.5, 58, 45.7, 36.4, 35.8,
32.5, 26.1, 16.4. HRMS: calcd for C25H34AuClN2 [M]+ 594.2076
found 594.2081.
Attila C. Benyei − Institute of Chemistry, University of Debrecen,
H-4032 Debrecen, Hungary; orcid.org/0000-0002-0617-
6264
́
́
Tamas Gati − Servier Research Institute of Medicinal Chemistry,
H-1031 Budapest, Hungary
Complete contact information is available at:
https://pubs.acs.org/10.1021/acs.organomet.0c00530
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
This research has been implemented in the framework of
project no. FIEK_16-1-2016- 0005 “Development of molecular
biomarker research and service center”, with support provided
from the National Research, Development and Innovation
Fund of Hungary, financed under the FIEK_16 funding
scheme. The research was also supported by the EU and
cofinanced by the European Regional Development Fund
under the projects GINOP-2.3.2-15-2016-00008 and GINOP-
2.3.3-15-2016-00004.
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R
https://dx.doi.org/10.1021/acs.organomet.0c00530
Organometallics XXXX, XXX, XXX−XXX