Gold(I) complexes bearing P-pyrrole phosphine ligands: Synthesis and catalytic activity towards cycloisomerization of 1,6-enynes

Article abstract of DOI:10.1002/aoc.5709

P-pyrrole phosphines (R₂Ppyr), in which a pyrrole group is directly bonded to the phosphorus atom, act as monodentate k-P ligands towards gold(I) center to afford either neutral or cationic mononuclear complexes as well as neutral dinuclear complexes. All of these new gold(I) complexes have been structurally characterized and their first uses in catalysis have demonstrated their effectiveness as precatalysts for the enyne cycloisomerization reactions.

Full text of DOI:10.1002/aoc.5709

Received: 2 November 2019
DOI: 10.1002/aoc.5709
Revised: 5 March 2020
Accepted: 8 March 2020
F U L L P A P E R
Gold(I) complexes bearing P-pyrrole phosphine ligands:
Synthesis and catalytic activity towards cycloisomerization
of 1,6-enynes
Elvia P. Sánchez-Rodríguez1 | Salvador Cortés-Mendoza1 | Jean-Claude Daran2
|
M. Carmen Ortega-Alfaro3 | José G. López-Cortés1
| Maryse Gouygou2
1Instituto de Química, Universidad
Abstract
Nacional Autónoma de México, Circuito
Exterior, Ciudad Universitaria, Coyoacán,
CdMx, C.P. 04510, Mexico
P-pyrrole phosphines (R2Ppyr), in which a pyrrole group is directly bonded to
the phosphorus atom, act as monodentate k-P ligands towards gold(I) center to
afford either neutral or cationic mononuclear complexes as well as neutral din-
uclear complexes. All of these new gold(I) complexes have been structurally
characterized and their first uses in catalysis have demonstrated their effective-
ness as precatalysts for the enyne cycloisomerization reactions.
2CNRS, LCC (Laboratoire de Chimie de
Coordination), Université de Toulouse,
UPS, 205, route de Narbonne, Toulouse,
31077, France
3Instituto de Ciencias Nucleares,
Universidad Nacional Autónoma de
México, Circuito Exterior, Ciudad
Universitaria, Coyoacán, CdMx, C.P.
04510, Mexico
K E Y W O R D S
catalysis, cycloisomerization, gold complexes, P-pyrrole phosphine ligand
Correspondence
José Guadalupe López-Cortés, Instituto de
Química, Universidad Nacional
Autónoma de México, Circuito Exterior,
Ciudad Universitaria, Coyoacán, C.P.
04510, CdMx. Mexico.
Email: jglcvdw@unam.mx
Maryse Gouygou, CNRS, Laboratoire de
Chimie de Coordination, Université de
Toulouse, UPS, 205, route de Narbonne,
31077. Toulouse, France.
Email: maryse.gouygou@lcc-toulouse.fr
Funding information
ECOS M13P02, Grant/Award Number:
229470; LIA Mexico-France: Laboratoire
de Chimie Moléculaire avec applications
dans les Matériaux et la Catalyse
(LCMMC), Grant/Award Number: 285722
1 | INTRODUCTION
electrophilic activation of alkynes under homogeneous
conditions, and a broad range of versatile synthetic tools
Gold(I) Au(I) complexes have received considerable
attention in the field of organic synthetic chemistry
owing to their ability to catalyze a broad range of trans-
formations.[1] They are the most effective catalysts for the
have been developed for the construction of carbon–car-
bon and carbon–heteroatom bonds.[1] The majority of
Au(I) complexes employed as catalyst precursors are
phosphine complexes or N-heterocyclic carbene
Appl Organomet Chem. 2020;e5709.
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© 2020 John Wiley & Sons, Ltd.
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https://doi.org/10.1002/aoc.5709

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SÁNCHEZ-RODRÍGUEZ ET AL.
complexes of the type [AuClL]. The active species are
often generated in situ by chloride abstraction on treat-
ment with a silver salt bearing a weakly coordinating
anion. However, the rapid decay of the cationic Au(I)
active species can be blamed for low turnover numbers[2]
which requires the use of relatively high catalyst load-
ings. This problem must be overcome in particular cases
using silver-free promoters,[3] special counterions,[4] or
bulky[5] or hemilabile phosphorus ligands.[6]
Steric congestion around the gold center imposed by
bulky ligands makes the electrophilic metal more stable,
leading to a longer catalyst lifetime. Several studies have
shown that cationic Au(I) complexes derived from Buc-
hwald-type biaryl phosphine-type ligands such as
BrettPhos[7] are more effective catalysts than those typi-
cally derived from triarylphosphines and N-heterocyclic
carbenes. Furthermore, Hashmi and coworkers reported
that the steric bulkiness of the phosphites (Figure 1a) is
the crucial factor for achieving long catalyst lifetimes for
intramolecular hydroalkoxylation, enyne cyclization, and
furanyne cyclization.[8]
On the other hand, hemilabile [P,N] ligands that
combine strongly and weakly coordinating groups in
their molecules can be used to stabilize the reactive cat-
ionic Au(I) intermediates as Au(I) dimers (Figure 1b).
Such [Au2L2]2+ provide good precatalysts which can split
into active monomers [AuL]+ by dissociation of the Au–
N bonds under the reaction conditions and can form
again once the catalytic product is released from the coor-
dination sphere.[9] In addition, bidentate [P,N] ligands
can be used to temper the reactivity of in situ-generated
α-oxo gold carbene intermediate through coordination of
the N group and the cationic gold center as reported with
Mor-DalPhos (Figure 1c).[10]
Our group is involved in the design of a new class of
phosphine ligands bearing an N,N-dimethyl-1H-pyrrol-
1-amine group (Figure 2). Recently, we demonstrated the
potential of these ligands in Pd-catalyzed Heck coupling
reactions,[11] intramolecular arylations,[12] and Ru-cata-
lyzed hydrogenation transfer reactions.[13] These ligands
have shown their ability to behave as bidentate [P,N]
ligands towards palladium(II). We postulated that these
trivalent phosphines (R2Ppyr) are a good alternative to
triphenylphosphine-based counterparts displaying more
steric bulkiness.
These ligands can be coordinated to Au(I) according
to a monodentate coordination mode leading to [AuXL]
complexes, or a bis (monodentate) coordination mode
leading to neutral [LAu2X2] or cationic [L2Au2]+ din-
uclear complexes. In addition, a potential interaction
could also occur between the N atom and the Au(I)
center.
The aim of this work was to explore the ability of the
P-pyrrole phosphines (R2Ppyr), in which a pyrrole group
is directly bonded to the phosphorus atom, to coordinate
the Au(I) metal center and the potential of the
corresponding complexes in catalysis. We report here the
synthesis, structural characterization of various com-
plexes, and preliminary results concerning their use in
1,6-enyne cycloisomerizations.
FIGURE 1 (a) Bulky phosphine and phosphite ligands, (b)
bis(monodentate) coordination mode in cationic Au(I) complex, (c)
interaction between the N atom and the Au(I) center in a carbene
intermediate
FIGURE 2 (a) P-pyrrole phosphine
ligands L bearing an N,N-dimethyl-1H-pyrrol-
1-amine group. (b) R2Ppyr L ligands used to
prepare Au(I) complexes

SÁNCHEZ-RODRÍGUEZ ET AL.
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2 | RESULTS AND DISCUSSION
2.1 | Synthesis and characterization of
gold complexes
The preparation of new Au(I) complexes has been accom-
plished from the R2Ppyr, L, depicted in Figure 2, using
the dimethylsulfide complex [AuCl(SMe)2] as Au(I) pre-
cursor. Three different types of complexes have been
obtained depending on the P substituents. The P-pyrrole
phosphine ligands L1–3 react with [AuCl(SMe2)] as
expected with replacement of the weakly coordinating
dimethylsulfide (SMe2) ligand to afford the corresponding
mononuclear Au(I) complexes [AuCl(L)] (Scheme 1).
Complexes [AuCl(L1–3)] were isolated in good yields
(80–88%) as white solids stable to air and were fully char-
acterized (see the Supporting Information).
Their structures were confirmed after X-ray diffrac-
tion analysis of single crystals grown in CH2Cl2/hexane
(1:1) in dichloromethane (DCM). All structures share
common features: a linear k-P coordination pattern of
gold and typical Au–P and Au–Cl bond lengths. No inter-
actions between the gold atom and the amino group or
intermolecular Au···Au contacts were detected in the
solid state (see the Supporting Information, Tables S8
and S9). The molecular structure of complex [AuCl(L1)]
is shown in Figure 3 (see the Supporting Information for
the molecular structures of [AuCl(L2)], Tables S8 and
S9, and [AuCl(L3)], Tables S10 and S11).
In solution, the k-P coordination of the ligands L1–3
was confirmed by a typical Δδ 31P chemical shift of ca.
40 ppm towards lower field.[13] The 31P{1H} NMR chemi-
cal shifts of the ligands and the resulting complexes
[AuCl(L1–3)] are summarized in Table 1. The MS spectra
of all [AuCl(L)] complexes show the signal for the
[AuL]+ ion and others signals as main peaks
corresponding to the [Au(L)2]+ and [Au2Cl(L)2]+ ions.
From these results, we can conclude that dinuclear struc-
tures, resulting from the k2-P of the ligands L1–3, are not
observed in either the solid state or solution.[14]
FIGURE 3 Molecular structure in the solid state of
[AuCl(L1)]. Selected bond lengths (Å) and angles (ꢀ): Au1–P1
2.2305(9), Au1–Cl1 2.2870(9), P1–Au1–Cl1 179.04(3)
TABLE 1
the corresponding gold complexesa (Δδ = δcomplex – δligand
31P NMR chemical shifts (ppm) for the ligand L and
)
δ
31P of L 31P of complex
12.5
δ
Δδ 31Pa
L1
L2
L3
L4
L5
−29.2
−45.7
1.9
41.7
37.9
42.5
70.6
28.1
−8.7
44.4
45.0
15.9
−25.7
−12.2
compared to the coordination shift of ca. 40 ppm for the
mononuclear complexes [AuCl(L1–3)] indicates a differ-
ent coordination pattern of gold in this complex
(Table 1). The ESI MS spectrum shows the signal at m/
z = 753.4 as the main peak, indicative of the [Au(L4)2]+
ion. The structure could be elucidated by X-ray structure
determination of single crystals grown from CH2Cl2-pen-
tane (Figure 4).
In contrast, L4 leads to the formation of a different
complex from those obtained for L1–3. This complex was
isolated in 76% yield and fully characterized. In 31P{1H}
NMR, the upfield coordination shift Δδ 31P of 70 ppm,
The gold atom is coordinated in an almost linear fash-
ion by two P atoms of two ligands. The P2–Au1–P1 angle
with 172.50(6)ꢀ slightly deviates from linearity. The Au–P
bond lengths, Au1–P1 2.3067(16)
Å and Au1–P2
2.3056(15) Å, are slightly longer than in the [AuCl(L1–3)]
complexes (see the Supporting Information, Tables S12
and S13). The [Au(L4)2]Cl complex is probably formed
via the [AuCl(L4)] intermediate, which undergoes substi-
tution of the halide by the more donating ligand L4.
With L5, another type of gold complex was obtained,
as evidenced by 31P NMR analysis. The downfield
SCHEME 1 Gold complexes obtained with ligands L1–5

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SÁNCHEZ-RODRÍGUEZ ET AL.
From these results, we can conclude that the P-pyr-
role phosphine ligands L1–L5 act as monodentate k-P
ligands towards the Au(I) center. The different structures
obtained seem to be dependent on the hindered demand
of the ligands. This was confirmed by the Tolman's cone
angle determined from the X ray structures of the
corresponding gold complexes (Tables 2 and S16). The
most congested ligands L1, L2 and L3 give [AuCl(L)]
mononuclear complexes while the least congested ligand
L5 leads to a dinuclear complex [AuCl(L5)]2. As for
ligand L4, which has an intermediate steric bulkiness,
the formation of the cationic complex [Au(L4)2]Cl can be
attributed to its more donor character than other ligands.
Finally, we observed that L1–L4 ligands are more
hindered demanding ligands than those of the PPh3
ligand, except for ligand L5.
FIGURE 4 Molecular structure in the solid state of [Au(L4)2]
Cl. Selected bond lengths (Å) and angles (ꢀ): Au1–P1 2.3067(16),
Au1–P2 2.3056(15), P2–Au1–P1 172.50(6)
coordination shift, Δδ 31P of 28 ppm, indicates a coordi-
nation pattern of gold different from those observed for
the mononuclear complexes [AuCl(L1–3)] and for the
cationic complex [Au(L4)2]Cl (Table 1). The ESI MS spec-
trum shows a signal for the ion [Au2Cl(L5)2]+ at m/
z = 925.2. The molecular structure (Figure 5), obtained
by X-ray diffraction analysis, confirms a dinuclear com-
plex [AuCl(L5)]2 in which the two Au(I) are equivalent
2.2 | Catalytic activity in 1,6-enyne
cycloisomerizations
The catalytic activity of gold complexes [AuCl(L1–3)],
[Au(L4)2]Cl, and [AuCl(L5)]2 was evaluated as pre-
catalysts in various in 1,6-enyne cycloisomerizations.[18]
For preliminary catalytic testing, we tested the activity of
the mononuclear gold complex [AuCl(L1)], focusing
and
nearly
linearly
coordinated
(P1–Au1–
Cl1 = 172.03(6)ꢀ).
TABLE 2
Tolman cone angle[16] of ligands L and PPh3
Tolman angle(º)
The Au–P and Au–Cl bond lengths are 2.2374(16) Å
and 2.3080(14) Å, respectively, and compare well with
the parameters previously reported for the [AuCl(L1–3)]
complexes (see the Supporting Information, Tables S14
and S15). The intramolecular Au1–Au1i distance of
3.0553(5) Å suggests an aurophilic d10–d10 interaction in
the solid state.[15] According to the coordination shift
observed in 31P NMR (Table 1), this aurophilic bonding is
retained in solution.
Ligand
[AuCl(L1)]
[AuCl(L2)]
[AuCl(L3)]
[Au(L4)2]Cl
[AuCl(L5)2]2
[AuCl (PPh3)]17
175.42
207.14
181.79
171.29
162.89
161.98
FIGURE 5 Molecular structure in the solid
state of [AuCl(L5)]2. Selected bond lengths (Å)
and angles (ꢀ): Au1–P1 2.2374(16), Au1–Cl1
2.3080(14), Au1–Au1i 3.0553(5), P1–Au1–Cl1
172.03(6), P1–Au1–Au1i 102.46(4)

SÁNCHEZ-RODRÍGUEZ ET AL.
5 of 9
initially on N-tethered 1,6-enyne substrate 1a. The reac-
tion was carried out in CH2Cl2 at room temperature with
the cationic catalyst generated from [AuCl(L1)] and vari-
ous AgX as halide scavenger. Among the silver salts used,
AgSbF6 afforded the best results in terms of conversion
and selectivity (see Table S1). Full conversion of 1a was
obtained in 1 hr using 3 mol% of cationic gold complex to
give 2a in excellent selectivity (2a:3a = 99:1), resulting
almost exclusively from a 6-exo-dig cyclization skeletal
rearrangement.[19] Interestingly, decreasing the catalytic
loading of [AuCl(L1)] from 3 mol% to 1 mol% still gave
full conversion, with 99% of 2a obtained in excellent
selectivity (Table 3, entry 1). Thus, the use of the
[AuCl(L1)]/AgSbF6 system proved particularly beneficial
for the cycloisomerization of enyne 1a in comparison to
cyclopropane 3b in 68:32 ratio (Scheme 2) resulting from
competition between the 6-endo-dig and the 5-exo-dig cycli-
zation skeletal rearrangements. These results contrast with
those reported by Echavarren and co-workers,[21a] who
described the formation of a mixture of 1,3-dienes 2b and
2b0 both resulting from a 5-exo-dig process in 52% yield
after 3 hr of reaction and the use of 2% [AuCl (PPh3)]/
AgSbF6. However, using the [AuCl(L2)] catalytic precursor,
enyne 1b underwent complete cycloisomerization into a
69:31 mixture of 1,3-dienes 2b and 2b0. This result shows
that the ligand can have an impact on the pathway of the
cyclization rearrangement.
We also examined the more demanding substrates 1c
and 1d, which were found to be rather reluctant to
cycloisomerize under various metal-catalyzed conditions.
[AuCl(L1)] proved far less effective as moderate conver-
sions (33–56%, see the Supporting Information, Tables S3
and S4) of enynes 1c and 1d were obtained in conditions
similar to those used previously for 1a. To obtain higher
conversions (86–87%) of 1c and 1d, the amount of cata-
lyst should to be increased to 3–5 mol% and the reaction
time to 4 hr (Scheme 2). The cyclopropane derivatives 3c
and 3d were obtained as the main product in similar con-
ditions as already reported for phosphine-based gold cata-
lyzed cycloisomerization of N-tethered enynes bearing a
substituent on the alkyne.[20c,d]
the use of other phosphine-based gold catalysts such as
[20a]
[AuCl (PPh3)]/AgSbF6
(2 mol%, 2a: 96%) and
[AuClSPO]/AgSbF6[21b] (2 mol%, 2a: 76–79%).
Under these optimized conditions, mononuclear com-
plexes [AuCl(L2)] and [AuCl(L3)] proved to be as active
but slightly less selective. Full conversion of 1a was again
observed to give diene 2a as the major product accompa-
nied by increased amounts of 3a showing a slight steric
effect of the ligand structure on the selectivity (Table 3,
entries 2 and 3).
Following this preliminary catalytic testing,
[AuCl(L1)]
was
selected
to
investigate
the
Finally, the [AuCl(L1)]/AgSbF6 system proved to be
very efficient in the cycloisomerization of the C-tethered
1,6-enyne 4. 1,3-dienes 5 and 6 were formed as major
products in 80:20 ratio, showing similar performances to
the [AuCl(PPh3)]/AgSbF6 system[21a] (Scheme 2).
cycloisomerization of various 1,6-enynes (Scheme 2). When
unsubstituted 1,6-enyne 1b was treated under the opti-
mized conditions, only 20% of conversion was recorded.
This reaction requires a higher catalyst load (5 mol%) to
proceed satisfactorily (see the supporting information,
Table S2). Under these conditions, 90% of enyne 1b was
converted, giving rise to a mixture of diene 2b and
We wished to look at the possibility of using the cat-
ionic gold complex [Au(L4)2]Cl and the neutral dinuclear
complex
[AuCl(L5)]2
for
cycloisomerization
TABLE 3
Au(I)-catalyzed cycloisomerization of N-tethered 1,6-enyne 1a
Entry
[Au]
x
y
1
1
1
1
1
2a:3a ratio[a]
99:1
1
2
3
4
5
[AuCl(L1)]
[AuCl(L2)]
[AuCl(L3)]
[Au(L4)2]Cl
[AuCl(L5)]2
1
1
95:5
1
94:6
0.65
0.5
90:10
98:2
[a]Conversion and selectivity were determined by 1HNMR spectroscopic analysis of the crude product.

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SÁNCHEZ-RODRÍGUEZ ET AL.
SCHEME 2 Scope of cycloisomerization
with [AuCl(L1)]
SCHEME 3 Possible decomposition of [Au(L4)2]+ into the catalytically active species [Au(L4)]+
transformations. Their catalytic activities were evaluated
using the prototypical N-tethered 1,6-enyne precursor 1a.
In an initial attempt, the cationic gold complex [Au(L4)2]
Cl was tested in silver-free conditions. No cyclization
product was detected when enyne 1a was treated with
1 mol% of complex at room temperature for 2 hr, show-
ing the stability of this complex, which cannot open a
coordination site to the substrate. When the reaction was
performed in the presence of an excess of AgSbF6
(1 mol%), full conversion of 1a was observed. The diene
2a is obtained as the major product accompanied by
minor amounts of 3a isomer (10%) as previously observed
with [AuCl(L1–3)] catalytic precursors (Table 3, entry 4).
Au(L4)2]Cl precursor proved to be also active (39% of
conversion) for the cycloisomerization of enyne 1b and
more selective (2b:3b:2b0 ratio = 85:15:0) than the
[AuCl(L1)] catalytic precursor (Scheme 2). To explain
these results, we suggest that AgSbF6 assists the decom-
position of [Au(L4)2]+ into the catalytically active
[Au(L4)]+, probably via the intermediate formation of an
Au(I)–Ag(I) heterobimetallic complex,[21] as depicted in
Scheme 3.
monomeric species [Au(L5)]+ (Table 3, entry 5). Treat-
ment of the enyne 1a with this catalytic system
afforded diene 2a with excellent selectivity (98%).
Given this result, the dinuclear complex [AuCl(L5)]2 is
as active and selective as [AuCl(L1)2] in the
cycloisomerization of 1a.
3 | CONCLUSION
The synthesis and characterization of five gold complexes
featuring P-pyrrole phosphine ligands have been
reported. P-pyrrole phosphine ligands act as mono-
dentate k-P ligands towards Au(I), leading different types
of complexes, neutral or cationic mononuclear as well as
neutral dinuclear, depending on the steric environment
caused by the substituents on the phosphorus atom.
Their first uses in homogeneous gold catalysis have been
described. These complexes afford efficient precatalysts
for a series of 1,6-enyne cycloisomerization reactions.
Although no N···Au interaction could be demonstrated,
the involvement of mixed cationic bimetallic complexes
as intermediates, resulting from the k2-P,N coordination
of the ligand to Au(I) and Ag(I), cannot be ruled out,
especially in the case of [AuL4]2Cl and [AuClL5]2. Fur-
ther studies will be dedicated to the synthesis of Au(I)
The evaluation of the dinuclear complex
[AuCl(L5)]2 was performed in the presence of silver
salt as the halide scavenger to break up the dinuclear
complex into the catalytically active cationic

SÁNCHEZ-RODRÍGUEZ ET AL.
7 of 9
bimetallic complexes to explore their potential in
catalysis.
J = 12.2 Hz), 128.9, 120.3 (d, J = 3.6 Hz), 116.9 (d,
J = 9.6 Hz), 109.4 (d, J = 10.6 Hz), 48.0. MS (ESI+) m/z
(%): 491 [AuL1]+, 785.2 [Au(L1)2]+, 1017 [Au2Cl(L1)2]+.
HRMS (ESI) m/z calc. for C18H19N2PAu [AuL1]
491.0951; found 491.0963.
4 | EXPERIMENTAL
All commercially available reagents were used as
received. Silver salts were stored under argon in Schlenk
tubes. Unless otherwise stated, all reactions were run
under argon using Schlenk techniques. DCM and pen-
tane were dried under N2 using a solvent purification sys-
tem (SPS). NMR spectra were recorded at 25ꢀC on a
Bruker 400 Ultrashield or Fourier 300 Ultrashield appara-
tus. 1H NMR and 13C{1H} NMR chemical shifts were
referenced to the solvent signal. 31P{1H} NMR chemical
shifts were referenced to an external standard (85% aque-
ous H3PO4). Multiplicity is indicated as follows: s = sin-
glet, d = doublet, t = triplet. Mass spectra analyses were
performed on an API-365 spectrometer (ESI) and on a
TSQ 7000 Thermoquest instrument (DCI). High-resolu-
tion mass spectra (HRMS) were recorded using a Waters
Xevo G2 QTof instrument. X-ray structures were deter-
mined on a Rigaku Oxford Diffraction GEMINI EOS dif-
fractometer for [AuCl(L1)] and [Au(L4)2]Cl and on a
Bruker Nonius APEXII diffractometer for [AuCl(L2)],
[AuCl(L3)], and [AuCl(L5)]2.
4.1.2 | Chloro(N,N-dimethyl-1H-pyrrol-
1-amine-2-o-tolylphosphine)Au(I),
[AuCl(L2)]
White solid, mp 210–211ꢀC (80%). Crystals were grown
by slow diffusion of hexane in DCM for 3 days at room
temperature. 31P NMR (161.99 MHz, CDCl3, ppm) δ: 8.7.
1H NMR (400.16 MHz, CDCl3, ppm) δ: 7.43 (tt, J = 7.5,
1.4 Hz, 2H), 7.36–7.34 (m, 1H), 7.31–7.30 (m, 2H), 7.18 (t,
J = 7.6 Hz, 2H), 6.90 (ddd, J = 13.8, 7.8, 1.3 Hz, 2H), 6.25
(dt, J = 4.1, 2.9 Hz, 1H), 5.80 (ddd, J = 4.1, 3.3, 1.7 Hz,
1H), 2.74 (s, 6H), 2.71 (s, 6H). 13C NMR (100.63 MHz,
CDCl3, ppm) δ: 132.2 (d, J = 9.2 Hz), 131.7 (d,
J = 2.4 Hz), 127.2, 126.6, 126.3 (d, J = 10.4 Hz), 120.9 (d,
J = 3.6 Hz), 118.1 (d, J = 10.4 Hz), 116.7, 115.8, 109.7 (d,
J = 10.8 Hz), 48.6, 29.8, 23.0 (d, J = 12.5 Hz). MS (ESI+)
m/z (%): 519.1 [AuL2]+, 841.3 [Au(L2)2]+, 1073.2
[Au2Cl(L2)2]. HRMS (ESI) m/z calc. for C20H23N2PAu
[AuL2]+ 519.1264; found 519.1278.
4.1 | Procedure for the synthesis of gold
complexes
4.1.3 | Chloro(N,N-dimethyl-1H-pyrrol-
1-amine-2-di-t-butylphosphine)Au(I),
[AuCl(L3)]
The starting ligands 1a–c[11] and 1d and 1e[12] were
synthetized according to the methodology previously
described and the full characterization is reported therein.
To a solution of [AuCl(SMe2)] (0.41 mmol) in 10 ml
of DCM was added the ligand (0.49 mmol). The reaction
was stirred at room temperature for 3 hr. The mixture
was concentrated to a minimum and the product precipi-
tated and washed five times with 10 ml of pentane.
White solid, mp 209ꢀC (85%). Crystals were grown by
slow diffusion of hexane in DCM for 3 days at room tem-
perature. 31P NMR (161.99 MHz, CDCl3, ppm) δ: 44.4. 1H
NMR (400.16 MHz, CDCl3, ppm) δ: 7.30 (ddd, J = 3.5,
3.0, 1.6 Hz, 1H), 6.51 (dd, J = 2.9, 1.2 Hz, 1H), 6.30–6.28
(m, 1H), 2.80 (s, 6H), 1.36 (d, J = 16.1 Hz, 18 H). 13C
NMR (100.63 MHz, CDCl3, ppm) δ: 120.4 (d, J = 2.5 Hz),
116.3, 115.6 (d, J = 4.4 Hz), 108.6 (d, J = 7.9 Hz), 48.3,
37.1 (d, J = 30.4 Hz), 30.2 (d, J = 7.0 Hz). MS (ESI+) m/z
(%): 451.2 [AuL3]+, 705.4 [Au(L3)2]+, 937.3
[Au2Cl(L3)2]+. HRMS (ESI) m/z calc. for C14H27N2PAu
[AuL3] + 451.1577; found 451.1597.
4.1.1 | Chloro(N,N-dimethyl-1H-pyrrol-
1-amine-2-diphenylphosphine)Au(I),
[AuCl(L1)]
White solid, mp 223–224ꢀC (80%). Crystals were grown
by slow diffusion of hexane in DCM for 3 days at room
temperature. 31P NMR (162 MHz, CDCl3, ppm) δ: 12.5.
1H NMR (400.16 MHz, CDCl3, ppm) δ: 7.65–7.60 (m, 4H),
7.52–7.43 (m, 6H), 7.24 (td, J = 3.2, 1.7 Hz, 1H), 6.22 (dt,
J = 4.0, 3.1 Hz, 1H), 5.76 (ddd, J = 4.3, 2.8, 1.7 Hz, 1H),
2.63 (s, 6H). 13C NMR (101 MHz, CDCl3, ppm) δ: 134.2
(d, J = 14.8 Hz), 131.9 (d, J = 2.6 Hz), 129.6, 129.1 (d,
4.1.4 | [Bis(N,N-dimethyl-1H-pyrrol-
1-amine-2-dicyclopentylphosphine)Au(I)]
chloride, [Au(L4)2]Cl
White crystal, mp 180ꢀC (76%). Crystals were grown by
slow diffusion of hexane in DCM for 3 days at room tem-
perature. 31P NMR (161.99 MHz, CDCl3, ppm) δ: 45.0. 1H

8 of 9
SÁNCHEZ-RODRÍGUEZ ET AL.
NMR (400.16 MHz, CDCl3, ppm) δ: 7.40 (d, J = 1.3 Hz,
1H), 6.49 (dd, J = 3.9, 1.8 Hz, 1H), 6.29 (dd, J = 3.9,
2.9 Hz, 1H), 3.14–3.09 (m, 2H), 2.88 (s, 6H), 2.23–2.21 (m,
2H), 1.78–1.76 (m, 12H), 1.69–1.64 (m, 2H). 13C NMR
(100.63 MHz, CDCl3, ppm) δ: 121.6, 119.5 (t, J = 9.1 Hz),
117.6, 109.7 (t, J = 5.9 Hz), 49.1, 36.7 (t, J = 18.5 Hz), 31.6
(d, J = 3.4 Hz), 29.8, 27.2 (t, J = 4.7 Hz), 26.0 (t,
J = 4.7 Hz). IR (ATR, cm−1) vmax: 2954, 912, 753, 733,
492. MS (ESI+) m/z (%): 753.4 [Au(L4)2]+. HRMS (ESI)
m/z calc. for C32H54N4P2Au [Au(L4)2]+ 753.3489; found
753.3525.
Chimie Moléculaire avec applications dans les Matériaux
et la Catalyse (LCMMC), Conacyt 285722 and ECOS
M13P02 (Conacyt 229470).
ORCID
José G. López-Cortés https://orcid.org/0000-0002-4508-
117X
Maryse Gouygou https://orcid.org/0000-0001-9429-
537X
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4.2 | Procedures for gold-catalyzed
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Enynes 1a,[22] 1b,[23] 1c,[24] 1d,[25] and 4[26] were synthe-
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ACKNOWLEDGMENTS
The authors would like to acknowledge the Institut de
Chimie du CNRS (Centre National de la Recherche
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SUPPORTING INFORMATION
Additional supporting information may be found online
in the Supporting Information section at the end of this
article.
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How to cite this article: Sánchez-Rodríguez EP,
Cortés-Mendoza S, Daran J-C, Ortega-Alfaro MC,
López-Cortés JG, Gouygou M. Gold(I) complexes
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