Reactivity studies of cationic Au(III) difluorides supported by N ligands

Lachlan Sharp-Bucknall, Lachlan Barwise, Jason D. Bennetts, Mohammad Albayer, and Jason L. Dutton*

Article

Reactivity Studies of Cationic Au(III) Diﬂuorides Supported by N

Ligands

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ABSTRACT: The reactivity of diﬂuoro Au(III) cations supported

by pyridine or imidazole ligands is reported. The Au(III)−F bond

is found to be susceptible to metathesis by TMS reagents and

reagents bearing acidic protons such as H−CC−Ph and HOAc. In

the last case the reactions are slower than analogous reactions

reported by other groups, where strong trans donors are present

opposite the Au−F bond. This, coupled with the inability to eﬀect metathesis on only one Au−F bond in our system, indicates that

the trans eﬀect is a key consideration in Au−F chemistry.

INTRODUCTION

We believe the main reason for the lack of reports of isolated

Au−F-containing compounds stems from the relative weakness

and therefore high reactivity of the bond. For example in

■

The chemistry of organometallic and coordination complexes

containing a Au−F bond is underdeveloped, with only eight

unique compounds for Au(I) and 16 for Au(III)

−6

7−17

compound 4 Menjon and co-workers found that the weakness

as well

as a single Au(II) complex having been characterized by X-

ray crystallography. The ﬁrst was described in 2005, with most

examples being reported in the past 5 years as interest in the

area has increased. Representative examples for Au(III) are

shown in compounds 1−4. However, despite being relatively

few in number the existing reports demonstrate that there is

potential for taking advantage of this functionality in a variety

of interesting contexts. For example, substituting the Au−F

groups for aryl using boron-based reagents has been shown to

result in C−C bond formation by reductive elimination from

of the Au−F bond resulted in the ﬂuoride being easily replaced

by the other halides. Pyridine-based systems have been used

to “tame” the reactivity of the Au−F bond by Riedel and co-

workers, and we recently reported a family of cationic

complexes with two Au(III)−F bonds trans to one another

supported by either pyridine or imidazole ligands (6DMAP

and 6IM; Scheme 2). Given the cationic nature of the

complex, the high oxidation state of Au, and the weak trans-

donating ability of the ﬂuorides with respect to each other, this

class of compound contains some of the shortest, strongest

the Au center (Scheme 1A). The mechanism for this reaction

was proposed to be via a concerted mechanism in which the

boron abstracts the Au−F simultaneously with C−C bond

Au−F bonds reported to date at 1.90 Å.

−

Only the [AuF ] anion has been structurally determined to

have a bond as short at 1.899−1.901 Å; the typical range for

an Au−F bond is 2−2.2 Å. Nevado has reported Au−F bonds

as short as 1.94 Å in compound 2 and related analogues, for

the Au−F bond trans to pyridine. The Au−F bonds trans to

formation. C(sp )−F bond formation via reductive elimination

was also demonstrated from related compounds. Nevado

reported a system based on derivatives of compound 2 with

evidence for direct transmetalation of the B−C bond onto

Au(III), followed by reductive elimination of C−C from Au

the formally anionic phenyl donor in these complexes is longer

(

Scheme 1B). Several earlier systems were reported using

at 2.01−2.02 Å. This bond in gas-phase AuF is also relatively

boron-based reagents to generate C−C bonds in Au(I)/

Au(III) redox couples using Selectﬂuor as an oxidant, but the

short at 1.88 Å. This feature of having a short, strong Au−F

bond makes our compounds ideal as a relatively stable

platform to explore the possibilities of Au−F chemistry within

a coordination complex.

19−22

proposed Au(III)−F intermediates were not isolated.

The

formation of a C−F bond on a propargyl acetate by Au(I)/

Au(III) and Selectﬂuor through a Au−F intermediate has also

been reported.

Received: June 23, 2020

Nevado has also demonstrated activation of C−H bonds by

isolable Au(III)−F to introduce acetylide (Scheme 1C) and

formate (Scheme 1D) fragments onto gold, the latter being

the ﬁrst example of a Au(III) formate. The use of an Au(III)−

F intermediate for Sonogashira type reactions has also been

proposed again using Selectﬂuor as an oxidant for Au(I).

XXXX American Chemical Society

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Scheme 1. (A) Reactivity Reported by Toste between Au−F and Boronic Acids, (B) the First Direct Evidence for

Transmetalation between Au−F and Boronic Acids by Nevado, Where Arylated Intermediates Were Isolated and C−C

Reductive Elimination Products Varied Depending on the R and Aryl Group Substituents, (C) Reactivity of Au−F with

Terminal Alkynes Reported by Nevado, and (D) Generation of the First Gold Formate from Au−F and Formic Acid

RESULTS AND DISCUSSION

F bond with chloride or teﬂate of an NHC−AuF complex

using the corresponding −TMS reagent.

To demonstrate that our Au(III)−F system was compatible

■

Delivery of Fragments to Au Using TMS Reagents.

Delivery of Pyridine. Trimethylsilyl (TMS) reagents are often

used to deliver fragments to species containing E−F bonds

owing to the high thermodynamic stability of the Si−F bond.

To date there has been only one report of manipulating an

Au−F bond with −TMS in which Riedel replaced an Au(III)−

with TMS metathesis reactions, we sought to generate a known

compound, the tetrakis(pyridine) species 8R. The TMS−

pyridine cations 7R were generated by a direct reaction

between TMS−OTf and the appropriate pyridine following the

literature procedure and can be isolated and stored for future

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Scheme 2. Synthetic Pathway for 6DMAP and 6IM

Scheme 3. Synthesis of 8R using 7R and 6DMAP

Scheme 4. Observed Reactivity between 9 and KF

Scheme 5. Synthesis of 11DMAP from TMS-CC-Ph and 6DMAP

use. The reaction of 2 equiv of 7R with 6DMAP in CH CN

with this system. The same conversion was also observed using

resulted in the generation of 8R over 4 days (Scheme 3).

During monitoring of the reaction, TMS−F could be observed

7NMe , giving the homoleptic trication 8NMe .

If only 1 equiv of 7R was used, no product consistent with a

in situ by F NMR, with a diagnostic singlet at −157 ppm.

[tris(pyridine)Au(III)−F] compound was observed. After 3

The conversion is quantitative, as determined by H NMR

spectroscopy, and the isolated yield of 8R was 84%,

demonstrating that TMS metathesis reactions are compatible

days in solution 7R and 6DMAP were still present, along with

TMS−F, a small amount of HF, and the Au(I) compound

5DMAP. Riedel reported the observation of HF in pyridyl−

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Scheme 6. Observed reactivity between 6DMAP and H−CC−Ph

Scheme 7. Synthesis of 11IM using 6IM and H−CC−Ph

Au(III) ﬂuorides in some cases and also reported that certain

Ph. The reaction of 6DMAP with 2 equiv of H−CC−Ph in

−

pyridine:F ratios result in unstable complexes. We have not

been successful in generating 10 by attempted displacement of

one pyridine from 9 using 1 equiv of KF (Scheme 4), which

results in decomposed reaction mixtures, indicating that

Au(III) bearing one ﬂuoride and three N ligands may not be

a stable class of compounds.

CH CN over 5 days with protection from light resulted in a

conversion to 11DMAP and elimination of HF, as monitored

by F and H NMR (Scheme 6). 11DMAP was isolated in

50% yield, comparable to that for the reaction with TMS−

CC−Ph. Nevado reported a similar reaction with an analogue

of compound 3, proceeding with excellent yields at room

Delivery of Phenylacetylene. Au(III) acetylides are of

interest, as they often give compounds containing interesting

temperature within 3 h. The extended reaction time in our

system is likely due to the labilizing eﬀect of the trans anionic

organometallic group in 3 in comparison to ours with a trans

−F. As with the −TMS reaction only substitution of both Au−

F bonds in 6DMAP is observed with H−CC−Ph using

substoichiometric amounts, consistent with the newly intro-

duced acetylide group rendering the trans −F much more

reactive.

Though 11DMAP can be formed via direct reaction with

both H−CC−Ph and TMS−CC−Ph, the reaction between

TMS−CC−Ph and 6IM resulted in complex mixtures where

11IM was observable in situ but not isolable. However, when

6IM was reacted with H−CC−Ph, 11IM was isolated cleanly

in 60% yield after 5 days (Scheme 7). The reason for the

diﬀering reactivity with TMS−CC−Ph between 6DMAP and

6IM is unclear but indicates within this system that the

substitution of related ligands for each other can have an eﬀect

on the reaction outcome and it is useful to have a library of

related complexes at hand.

,30−32

luminescent properties.

To determine if Au−F can be

switched for an acetylide functionality, 6DMAP was reacted

with 2 equiv of TMS−CC−Ph in CH CN. TMS−F was

observed in the ¹⁹F NMR, and 6DMAP was completely

consumed within 1 h. After workup, mass spectrometry and

NMR studies were consistent with the complex 11DMAP,

which was isolated in 60% yield (Scheme 5). 11DMAP is still

isolated as the exclusive Au−acetylide product if less than 2

stoichiometric equiv of TMS−CC−Ph is used. We hypothesize

that this is due to the superior trans-donating ability of the

acetylide, which renders the opposite ﬂuorine atom much

more reactive for the second substitution to occur. We have

been unable to obtain single crystals suitable for X-ray

diﬀraction studies to conﬁrm if the acetylide fragments are

orientated cis or trans about the Au(III) center. However, in all

cases where we have obtained X-ray structures for this family

of Au(III)−pyridyl-supported cations the strongest and

weakest pairs of trans donors are oriented trans to one

Delivery of −CN via TMS. Next, we investigated the

4,27,33

another;

1DMAP is most likely trans. This arrangement is also

observed in other structurally characterized Au(III) diﬂuorides

therefore, we surmise the arrangement in

reactivity of TMS−CN with 6DMAP. Upon reaction for 3 h in

CH CN 6DMAP was consumed and TMS-F was generated, as

monitored by F NMR spectroscopy. Initially we believed that

the ﬂuorides had been substituted by CN groups, following a

pathway analogous to the process involving TMS−CC−Ph

and 6DMAP. However, further analysis of the reaction

bearing two other monodentate ligands such as −CF .

Delivery of Phenylacetylene by C−H Activation. TMS

elimination, while eﬀective, suﬀers from high cost and a low

atom eﬃciency. Having established the stability of compound

products via mass spectrometry and H NMR revealed the

−

11DMAP ,we sought to synthesize it directly from H−CC−

presence of both [Au(CN)₄] and 8NMe , respectively

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Scheme 8. Observed reactivity between TMS−CN and 6DMAP

Scheme 9. Observed Reactivity of 6DMAP and PhI(OAc) or Acetic Acid

(

Scheme 8). Single crystals were grown via CH CN/Et O

studies showed an ion with an m/z value of 559.2, consistent

with the cation 12DMAP (Scheme 9).

vapor diﬀusion. Crystallographic studies showed a salt with

cocrystallization of [Au(CN) ] , OTf , and the 8NMe

−

Reaction of Au(III) Diﬂuorides with HOAc. Attempts to

generate 12DMAP using HOAc from the 8R starting material

were not successful, giving complex mixtures. The reaction was

only successful if the Au(III) center was supported by a

trication. We speculate that the target bis(cyano) bis(pyridyl)

complex was formed temporarily via ligand delivery from

TMS; however, this species then underwent ligand exchange to

produce the observed products. We have not observed such an

intermediate, however. Scrambling behavior such as this has

bidentate or tridentate pyridyl ligand. In situ monitoring of

the reaction of 6DMAP with HOAc in CD CN showed a set

of H NMR signals identical with those of 12DMAP.

previously been observed with halides of Au(III).

2DMAP could be isolated in 86% yield. The above two

Reaction of Au(III) Diﬂuorides with PhI(OAc) . Previous

reactions giving diacetate compounds demonstrate cases where

a product can be achieved from an Au−F bond that could not

be accessed via other available methods. In attempts to obtain

single crystals for X-ray studies for structural conﬁrmation of

the transformation, as we were unable to grow suitable crystals

of the above compounds, we sought to synthesize 12IM. In the

eﬀorts in our laboratory to synthesize the diacetate compounds

combination of 5DMAP and PhI(OAc)₂resulted in no

reaction, likely due to the relatively modest oxidative ability

2DMAP and 12IM have been unsuccessful, as the

of PhI(OAc)₂.

Recently we reported that cationic diﬂuorogold systems

reaction of 6IM with HOAc H NMR and mass spectral data

DMAP and 6IM can undergo metathesis reactions with

consistent with 12IM were observed. This was conﬁrmed by

X-ray structural studies on single crystals grown via vapor

diﬀusion of Et O into a CH CN solution of the cation. As

[PhI(pyridine)₂] species via nucleophilic attack from ﬂuoride

onto the iodine, resulting in transfer of pyridine to the gold and

generation of PhIF₂. To investigate if 6DMAP can also react

with I(III) species bearing anionic ligands to give 12DMAP,

which we were unable to synthesize oxidatively from Au(I), it

was reacted with PhI(OAc) in CH CN, resulting in a color

change from yellow to orange. After 2 h, in situ F NMR

showed the generation of PhIF as a singlet at −176 ppm.

The mixture was reacted for 30 h, resulting in isolation of a

expected, the acetate ligands are orientated trans to one

another (Figure 1). Nevado and co-workers have generated

Au(III)−formates from the direct reaction of formic acid and

Au(III)−F.

Boronic Acids. Au(III) ﬂuoride compounds with strong

trans ligands with respect to the Au−F bond are known to

react with arylboronic acids, giving complexes that result in C−

8,10

bright orange solid after workup. H NMR spectroscopy of the

C bond formation.

To investigate if the more strongly

isolated material was consistent with a compound containing

bound Au−F in 6DMAP was susceptible to aryl trans-

-DMAP and acetate in a 1:1 ratio, and mass spectrometry

metalation, it was reacted with ArB(OH) (Ar = −Ph, 4-F−

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be a useful tool in Au reactivity. Finally, boronic acids react

with Au−F, consistent with related reports from other groups,

and the consequent C−C bond formation shows that the

elementary step of reductive elimination is a consideration in

the bis(pyridyl) Au(III) system being worked with and a

possibility in related compounds going forward.

EXPERIMENTAL DETAILS

Solvents used were dried using an Innovative Technologies Solvent

Puriﬁcation System. The dried solvents were stored under a N

■

atmosphere over 3 Å molecular sieves in the glovebox. Solvents for

NMR spectroscopy were purchased from Cambridge Isotope

Laboratories, dried by stirring for 3 days over CaH , distilled prior

to use, and stored in the glovebox over 3 Å molecular sieves. All NMR

spectroscopy was performed on 400 or 500 MHz Bruker

spectrometers at 300 K. 6IM, 6DMAP, and 7R species were

14,28

synthesized via literature procedures.

Gold powder was purchased

from Precious Metals Online. All other reagents were purchased from

Sigma-Aldrich and used as received. All reactions were performed

either within a glovebox or Schlenk line under dry N gas at room

temperature.

Figure 1. Solid-state structure of 12IM. Thermal ellipsoids are drawn

at the 50% probability level. The triﬂate anion is omitted for clarity.

Selected bond distances (Å): Au1−O1 1.993(2), Au1- O2 1.991(2),

Au1−N1 2.004(3), Au1−N2 2.000(3).

X-ray Crystallography Details. Single crystals were selected

under Paratone-N oil, mounted on nylon loops, and placed into a cold

stream (172 K) of N on a Rigaku SuperNova CCD diﬀractometer

using Cu Kα radiation. Structure solution and reﬁnement were

performed using the SHELXTL suite of software.

Reaction of 6DMAP and 7NMe . To a solution of 6DMAP (20

Ph). Over a 3 h period, the reaction solution changed from

clear yellow to a black suspension, indicative of decomposition

products. In H NMR of the suspension, both the Au(I)

mg, 0.032 mmol) in 2 mL of CH CN was added 7NMe (22 mg,

.064 mmol). The resulting solution was stirred for 4 days, producing

a red solution; volatiles were removed in vacuo to give a red solid. H

compound 5DMAP and the biphenyl C−C coupling product

NMR identiﬁed the product as 8NMe , matching known literature

corresponding to each boronic acid were observed (Scheme

data (29 mg, 82% yield).

H NMR (400 MHz, CD CN): δ (ppm) 7.96 (d, 8H, J = 7.7 Hz),

0). These results are indicative of transmetalation reactivity

with boronic acids despite the stronger Au−F bond in

DMAP. The likely diarylated intermediate then undergoes

.71 (d, 8H, J = 7.7 Hz), 3.10 (s, 24H).

Reaction of 6DMAP and 7H. To a solution of 6DMAP (20 mg,

.032 mmol) in 2 mL of CH CN was added 7H (19 mg, 0.064

reductive elimination with C−C bond formation. A mass

spectrum of the reaction mixture shows a small amount of a

molecular ion with a mass consistent with this species for both

X = H and X = F, but we have not been able to isolate a

diarylated compound. This is an important observation in that

some Au(III)−organo species supported by pyridine ligands

may not be viable, rather being susceptible to reductive

elimination.

mmol). The resulting solution was stirred for 4 days, producing a red

solution; volatiles were removed in vacuo to give a dark red solid. H

NMR identiﬁed the product as 8H, matching known literature data

(28 mg, 84% yield).

H NMR (400 MHz, CD CN): δ (ppm) 8.78 (t, 4H, J = 6.0 Hz),

8.37 (t, 2H, J = 7.7 Hz), 7.97 (d, 4H, J = 7.8 Hz), 7.86 (d, 4H, J = 7.1

Hz), 6.67 (d, 4H, J = 7.9 Hz), 3.09 (s, 12H).

Synthesis of 11DMAP using 1-Phenyl-2-trimethylsilylacety-

lene. To a solution of 6DMAP (39 mg, 0.062 mmol) in 4 mL of

CH CN was added 1-phenyl-2-trimethylsilylacetylene (37 μL, 0.188

mmol). The solution was stirred for 1 h before being ﬁltered,

CONCLUSIONS

The reactivity of [Au(Py) F ] cations was examined. They are

■

concentrated in vacuo, and treated with Et O to give 11DMAP as a

susceptible to both −TMS and −H metathesis reactions to

introduce other functionalities onto the Au(III) center. The

reactions involving acetylene (C−H) proceed more slowly

than for known systems with strong trans donors opposite to

the Au−F bond. The inability of our system to achieve

monosubstitution with a new anionic group trans to Au−F

indicates that the trans eﬀect is a key feature of Au(III)−F

chemistry. We were able to access diacetate compounds

inaccessible from oxidation of Au(I) using a conventional

cream-colored solid (30 mg, 61% yield).

H NMR (500 MHz, CD CN): δ (ppm) 8.43 (d, 4H, J = 7.8 Hz),

.34−7.28 (m, 10H), 6.74 (d, 4H, J = 7.8 Hz), 3.12 (s, 12H).

NMR (125 MHz, CD CN): δ (ppm) 156.6, 151.1, 132.5, 129.4,

29.0, 125.1, 109.4, 104.7, 96.9, 40.1. ESI-MS: m/z 643.2 [Au-

(DMAP) (CC-Ph) ] , molecular formula AuC H N , calculated

2 2 30 30 4

mass 643.21.

Synthesis of 11DMAP using Phenylacetylene. To a solution

of 6DMAP (33 mg, 0.053 mmol) in 4 mL of CH CN was added

phenylacetylene (14 μL, 0.128 mmol). The resulting solution was

stirred for 5 days in darkness before being ﬁltered, concentrated in

reaction from PhI(OAc) , indicating that the Au−F bond may

Scheme 10. Observed Reactivity between Phenylboronic Acids and 6DMAP

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vacuo, and treated with Et O to give 11DMAP as a cream-colored

solid (21 mg, 50% yield).

NMR spectra of reaction mixtures and isolated

compounds (PDF)

Synthesis of 11IM. To a solution of 6IM (50 mg, 0.091 mmol) in

mL of CH CN was added phenylacetylene (22 μL, 0.20 mmol).

Accession Codes

The resulting solution was stirred for 5 days in darkness prior to being

CCDC 2009722−2009723 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.

ﬁltered, concentrated to 1 mL, and treated with Et O to give 11IM as

a beige solid (40 mg, 62% yield).

H NMR (400 MHz, CD CN): δ (ppm) 8.68 (s, 2H), 7.84 (t, 2H,

J = 1.7 Hz), 7.51−7.46 (m, 4H), 7.38−7.35 (m, 6H) 7.34 (t, 2H, J =

.6 Hz) 3.87 (s, 6H). C NMR (125.8 MHz, CD CN): δ (ppm)

42.5, 132.8, 131.0, 129.5, 129.3, 125.0, 123.6, 100.5, 98.4, 36.5. ESI-

MS: m/z 563.1 [Au(methylimidazole) (CC−Ph) ] , molecular

formula AuC H N , calculated mass 563.15.

AUTHOR INFORMATION

Corresponding Author

■

Synthesis of 12IM. To a solution of 6IM (31 mg, 0.057 mmol) in

mL of CH CN was added 25 μL of glacial acetic acid (26 mg, 0.44

Jason L. Dutton − Department of Chemistry and Physics, La

Trobe Institute for Molecular Science, La Trobe University,

Melbourne, Victoria, Australia 3086; orcid.org/0000-0002-

mmol). The resulting solution was stirred for 16 h. Volatiles were

removed in vacuo, and the residue was redissolved in minimal CH CN

and treated with Et O to give 12IM as a beige solid (22 mg, 62%

361-4441 ; Email: j.dutton@latrobe.edu.au

yield).

H NMR (400 MHz, CD CN): δ (ppm) 8.09 (s, 2H), 7.31 (s,

Authors

H), 7.18 (s, 2H), 3.83 (s, 6H), 2.07 (s, 6H). C NMR (125 MHz,

Lachlan Sharp-Bucknall − Department of Chemistry and

Physics, La Trobe Institute for Molecular Science, La Trobe

University, Melbourne, Victoria, Australia 3086

Lachlan Barwise − Department of Chemistry and Physics, La

Trobe Institute for Molecular Science, La Trobe University,

Melbourne, Victoria, Australia 3086

Jason D. Bennetts − Department of Chemistry and Physics, La

Trobe Institute for Molecular Science, La Trobe University,

Melbourne, Victoria, Australia 3086

CD CN): δ (ppm) 176.3, 138.5, 125.8, 123.8, 36.5, 21.3. ESI-MS: m/

z 479.2 [Au(Methylimidazole) (OAc) ] , molecular formula

AuC H N O , calculated mass 479.10.

Synthesis of 12DMAP. To a solution of 6DMAP (24 mg, 0.038

mmol) in 4 mL of CH CN was added 25 μL of glacial acetic acid (26

mg, 0.44 mmol). The resulting solution was stirred for 16 h to give an

orange solution. Volatiles were then removed under reduced pressure,

and the residue was redissolved in minimal CH CN and treated with

Et O to give 12DMAP as a bright orange solid (23 mg, 86% yield).

H NMR (400 MHz, CD CN): δ (ppm) 7.93 (d, 4H, J = 7.6 Hz),

Mohammad Albayer − Department of Chemistry and Physics,

La Trobe Institute for Molecular Science, La Trobe University,

Melbourne, Victoria, Australia 3086

.73 (d, 4H, J = 7.6 Hz), 3.12 (s, 12H), 1.94 (s, 6H). C NMR (125

MHz, CD CN): δ (ppm) 176.2, 157.0, 147.0, 109.3, 40.1, 21.2. ESI-

MS: m/z 559.2 [Au(DMAP) (OAc) ] , molecular formula

AuC H N O , calculated mass 559.16.

https://pubs.acs.org/10.1021/acs.organomet.0c00429

Reaction of PhI(OAc) with 6DMAP. To a solution of 6DMAP

(

30 mg, 0.048 mmol) in 4 mL of CH CN was added PhI(OAc) ( 18

mg, 0.056 mmol). The resulting solution was stirred for 30 h, and

volatiles were then removed in vacuo to give an orange residue. The

Notes

The authors declare no competing ﬁnancial interest.

residue was then redissolved in minimal CH CN and treated with

Et O to give a bright orange solid that was washed with CHCl and

ACKNOWLEDGMENTS

■

then Et O to give 12DMAP (10 mg, 29% yield). NMR spectroscopy

We thank The La Trobe Institute for Molecular Science for

generous funding of this project. This work was also supported

by an ARC Future Fellowship (J.L.D., FT16010007) and ARC

Discovery Project (DP200100013).

and mass spectrometry produced data identical with those for

2DMAP.

Reaction of 6DMAP with TMS−CN. To a suspension of

DMAP (32 mg, 0.051 mmol) in 5 mL of DCM was added TMS−

CN (14 μL, 0.11 mmol). The resulting solution was stirred for 3 h

prior to being ﬁltered, concentrated in vacuo, and treated with Et O to

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ASSOCIATED CONTENT

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sı Supporting Information

The Supporting Information is available free of charge at

https://pubs.acs.org/doi/10.1021/acs.organomet.0c00429.

Organometallics XXXX, XXX, XXX−XXX

Organometallics

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