A three-step process to facilitate the annulation of polycyclic aromatic hydrocarbons

Article abstract of DOI:10.1021/jo501576e

A new efficient three-step process to annulate polycyclic aromatic hydrocarbons (PAHs) has been developed, providing access to PAHs with saturated rings that under current chemical methods would be difficult to produce in an efficient manner. This method relies on a palladium-catalyzed cross-coupling reaction of various brominated PAHs with cyclohexanone to yield α-arylated ketones, which are converted to regiospecific vinyl triflates and cyclized by a palladium-catalyzed intramolecular arene-vinyl triflate coupling to produce PAHs with incorporated saturated rings or "tetrahydroindeno-annulated" PAHs.

Full text of DOI:10.1021/jo501576e

Article
pubs.acs.org/joc
A Three-Step Process To Facilitate the Annulation of Polycyclic
Aromatic Hydrocarbons
Sara E. Martin,† Matthew D. Streeter, Laurel L. Jones, Matthew S. Klepfer, Kyriakos Atmatzidis,
,§
†,§
†
†
†
†
†
†
†
‡
Kristen D. Wille, Sean A. Harrison, Edward D. Hoegg, Heather M. Sheridan, Stephanie Kramer,
‡
,†
Damon A. Parrish, and Aaron W. Amick*
†Department of Chemistry, Washington College, 300 Washington Avenue, Chestertown, Maryland 21620, United States
‡Naval Research Laboratory, 4555 Overlook Avenue, Washington, D.C. 20375, United States
*
S Supporting Information
ABSTRACT: A new efficient three-step process to annulate
polycyclic aromatic hydrocarbons (PAHs) has been developed,
providing access to PAHs with saturated rings that under
current chemical methods would be difficult to produce in an
efficient manner. This method relies on a palladium-catalyzed
cross-coupling reaction of various brominated PAHs with
cyclohexanone to yield α-arylated ketones, which are converted to regiospecific vinyl triflates and cyclized by a palladium-
catalyzed intramolecular arene−vinyl triflate coupling to produce PAHs with incorporated saturated rings or “tetrahydroindeno-
annulated” PAHs.
INTRODUCTION
PAH (1) with cyclohexanone to produce an α-arylated ketone
■
12
(
2), which can be converted to a vinyl triflate (3). This
In recent years, the synthesis of complex polycyclic aromatic
1
conversion is followed by a palladium-catalyzed intramolecular
hydrocarbons (PAHs), such as large flat PAHs, saddle-shaped
2
3
4,5
10,13
PAHs, belt-shaped species, geodesic polyarenes, and single-
arene−vinyl triflate coupling
to close a five-membered ring,
6
walled carbon nanotubes (SWCNTs), has become vitally
important to the development of organic materials because of
producing a tetrahydroindeno-annulated PAH (4) that is highly
soluble in various organic solvents (Scheme 1). An extension of
our process to multiple annulations could allow for the
formation of soluble flat and curved PAHs containing
tetrahydroindeno groups, which could be converted to their
7
their physical and electronic properties. As the interest in these
non-natural products has increased, the number of synthetic
methods that can be employed to create these molecules has
not kept pace.
The key step in the chemical synthesis of complex PAHs,
specifically geodesic polyarenes, is an annulation reaction that
forms five-membered rings. Currently, there are three main
methods to create five-membered rings within PAHs; these are
9
fully aromatized analogues with the use of an oxidant.
Scheme 1. New Process To Create Structurally Diverse
Tetrahydroindeno-Annulated PAHs
8
flash vacuum pyrolysis (FVP), acid-catalyzed cyclodehydra-
9
10,11
tion, and palladium-catalyzed cyclization.
In recent years
palladium-catalyzed cyclization has become the preferred
method for PAH synthesis. This method was pioneered in
10
the early 1990s by Rice and co-workers with the development
of an ingenious multistep process to create a vast array of
PAHs. Their process relies upon an intramolecular palladium-
catalyzed arene−triflate coupling reaction to produce their
desired PAH products. This arene−triflate coupling reaction is
an efficient process; however, the production of the synthetic
intermediates for this process requires harsh reaction
conditions and multiple functional group transformations and
cannot be used to create PAHs with saturated rings.
In this paper, we present a new process to efficiently annulate
PAHs that utilizes mild reaction conditions and minimal
functional group transformations to produce a wide variety of
PAHs that contain saturated rings. Our new method relies on a
palladium-catalyzed cross-coupling reaction of a brominated
Received: July 15, 2014
©
XXXX American Chemical Society
A
dx.doi.org/10.1021/jo501576e | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
RESULTS AND DISCUSSION
hindered environment around the bromine, as 1-bromoan-
thracene (1e) reacts smoothly under the optimized conditions
to yield α-arylated ketone 2e in a 69% isolated yield. Due to the
extremely low yield of ketone 2f, we chose not to continue to
examine this substrate in further transformations. Ketones
■
Our study began with the optimization of the palladium-
12
catalyzed cross-coupling reaction of cyclohexanone with
various structurally diverse brominated PAHs 1a−f (Figure 1).
2a,b,d crystallized after purification, allowing for X-ray crystal
structures to be determined for these compounds (see the
Supporting Information).
For annulation to be possible, the ketone in compounds 2a−
e must be converted to a functional group that is more
amenable for metal-catalyzed cyclization. Our choice was to
convert this ketone to a vinyl triflate through the capture of an
15
enolate with a triflating agent. Examining ketone 2a, it can be
observed that there are two possible sites for deprotonation,
yielding either the desired thermodynamic vinyl triflate 3a
(
(
highlighted in red) or the undesired kinetic vinyl triflate 5
highlighted in blue) (Scheme 3).
Figure 1. Brominated PAHs investigated in this study.
Scheme 3. Two Possible Vinyl Triflates Produced after
Deprotonation of α-Arylated Ketone 2a
Reaction conditions that utilized 3−6 mol % of Pd(OAc) ,
2
7
.5−15 mol % of either S-Phos or X-Phos as the ligand, and 1
mol equiv of Cs CO as a base in anhydrous toluene at 110−
2
3
1
2
15 °C afforded the best results, providing α-arylated ketones
14
a−e from brominated PAHs 1a−e in good yields ranging
from 54 to 69% (Scheme 2). The cross-coupling of 9-
bromoanthracene (1f) with cyclohexanone failed to yield α-
arylated ketone 2f in any appreciable amounts under various
reaction conditions. We attribute this failure to the sterically
Scheme 2. Substrate Scope of the Palladium-Catalyzed
Cross-Coupling of Brominated PAHs with Cyclohexanone
To Produce α-Arylated Ketones 2a−f
Our investigation into conditions that would create the
thermodynamic vinyl triflates of ketones 2a−e was accom-
plished using α-arylated ketone 2a as a model system. We
began using N-phenylbis(trifluoromethanesulfonimide) (trifli-
mide) as the triflating agent and strong bases such as potassium
hexamethyldisilazane (KHMDS) and sodium hydride (NaH) in
tetrahydrofuran (THF) as the solvent. These reactions
produced the undesired kinetic vinyl triflate 5 or no reaction
in the case of NaH. Holton and Kraft reported that
bromomagnesium diisopropylamide (BMDA) was effective
in the production of thermodynamic silyl-enol ethers in
substituted cyclohexanones; however, when this method was
attempted on our system, it failed to yield the desired isomer
16
3
a.
Our focus then shifted to weaker alkoxide bases that should
be more able to establish an equilibrium, allowing for the
selective formation of the desired vinyl triflate 3a. Sodium
ethoxide proved to be sparingly soluble in organic solvents such
as dichloromethane (DCM) and tetrahydrofuran (THF) and
yielded very little of either regioisomers of the vinyl triflate. We
then explored potassium tert-butoxide’s ability to create 3a.
Attempts to use potassium tert-butoxide in anhydrous THF did
produce a small amount of the desired 3a but catalyzed
numerous side reactions, producing countless byproducts. We
also examined anhydrous DCM as the solvent and found that
only the desired thermodynamic vinyl triflate 3a was produced.
Further optimization showed that 3 mol equiv of tert-butoxide
and 1 mol equiv of triflimide added dropwise produced the best
results and gave 3a in a 77% isolated yield.
a
Conditions: 3 mol % of Pd(OAc) , 7.5 mol % of S-Phos, 1.5 equiv of
2
b
cyclohexanone, 1 equiv of Cs CO , toluene (anhydrous). Conditions:
3
cyclohexanone, 1 equiv of Cs CO , toluene (anhydrous). Conditions:
6
2
3
Despite the success of these conditions on 2a to produce 3a,
expansion of this method to ketones 2b−e proved to be
impractical, as the separation of the desired vinyl triflates from
the amine byproduct of triflimide was not possible. To rectify
mol % of Pd(OAc) , 7.5 mol % of X-Phos, 1.5 equiv of
2
c
2
3
mol % of Pd(OAc) , 15 mol % of X-Phos, 1.5 equiv of
2
cyclohexanone, 1 equiv of Cs CO , toluene (anhydrous).
2
3
B
dx.doi.org/10.1021/jo501576e | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
this issue, we changed the triflating agent to triflic anhydride
and found that 2a could be converted to vinyl triflate 3a in an
mixture was heated under microwave irradiation at 150 °C, at
200 W maximum power for 1 h. Vinyl triflates 3a−e were
successfully closed to provide annulated PAHs 4a−e in yields
ranging from 30 to 88%, and the reaction can be run on a larger
scale, as demonstrated by the cyclization of 3d to 4d, which was
run on a near 2.0 mmol scale (Scheme 5).
8
5% isolated yield. These conditions were widely applicable and
smoothly converted 2b−e to their corresponding vinyl triflates
3
b−e with 3 equiv of potassium tert-butoxide and 2 equiv of
triflic anhydride (added dropwise) in anhydrous DCM. The
yields of vinyl triflate formation were excellent and ranged from
70 to 88% (Scheme 4). One of the greatest benefits of these
Scheme 5. Substrate Scope of the Optimized Palladium-
Catalyzed Intramolecular Arene−Vinyl Triflate Coupling
Scheme 4. Substrate Scope for the Conversion of α-Arylated
Ketones 2a−e to Vinyl Triflates 3a−e using Optimized
Reaction Conditions
reactions is they are self-indicating, as the solution of potassium
tert-butoxide and 2a−e undergoes a color change, which is
persistent until all of the ketone has been consumed to produce
vinyl triflates 3a−e.
With vinyl triflates in hand, the palladium-catalyzed closure
of compounds 3a−e was investigated under microwave
1
1d,e
irradiation conditions using a variant
of the arene−triflate
10
coupling method developed by Rice and co-workers.
Optimization of the arene−vinyl triflate coupling was
accomplished by examining the amount of time that was
needed for this reaction to go to completion, the temperature,
the amount of LiCl that was needed, catalyst loading, and if the
reaction could be set up on the benchtop or in an inert-
atmosphere glovebag. We chose to use Pd(PCy ) Cl as the
a
Percentages were determined by GC integration. Yields reported for
a−e were obtained using the following optimized reaction
4
conditions: 10 mol % of Pd(PCy ) Cl and 3 equiv of LiCl, added
3
2
2
3
2
2
in an inert-atmosphere glovebag, 2 equiv of DBU, and anhydrous
DMAc as the solvent with heating under microwave irradiation at 150
°C, at 200 W maximum power for 1 h.
catalyst for the arene−vinyl triflate coupling because it is an
electron-rich catalyst that would allow for facile oxidative
addition into the alkene−triflate bond and because it has a
proven track record to efficiently catalyze the σ-bond
The arene−vinyl triflate coupling to produce substrates
4a,c,e occasionally suffered from a minor amount of reductive
detriflation (ca. 9−20%) to yield the open products 4a-1, 4c-1,
and 4e-1. This reductive detriflation can be attributed to trace
amounts of water introduced by the very hygroscopic LiCl. To
test this hypothesis, we ran two arene−vinyl triflate coupling
reactions on compound 3a: in one we added 0.50 equiv of
water, and in the second we allowed the LiCl to be exposed to
air for 5 min. Both produced exclusively the detriflated product
11d−g
metathesis on numerous strained PAHs.
We found that
the best results were obtained by the use of 10 mol % of
Pd(PCy ) Cl and 3 equiv of LiCl, which were added to the
3
2
2
microwave vessel in an inert-atmosphere glovebag. Once the
solids had been added, the vessel was capped and removed
from the glovebag, at which point 2 equiv of 1,8-
diazabicyclo[5.4.0]undec-7-ene (DBU) and anhydrous N,N-
dimethylacetamide (DMAc) were added and the reaction
C
dx.doi.org/10.1021/jo501576e | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
1
7
4
a-1. Arene−vinyl triflate couplings to yield compounds 4c,e
equipped with a vent needle, and it was flushed with nitrogen for 15
min. Cyclohexanone (290 mg, 3.0 mmol) and 2.0 mL of toluene
also showed aromatization of the saturated ring, producing fully
aromatized compounds 4c-2 and 4e-2, which we believe stems
(
anhydrous) were added via a syringe through the septum. The
18
septum was removed under a constant nitrogen flow and capped with
a Teflon screw cap. The reaction was stirred at room temperature for
from the presence of oxygen in the reaction. To solve the
detriflation and aromatization issues, reactions were set up in a
glovebag to eliminate most traces of water and oxygen, which
proved fruitful, as this drastically reduced the amount of
detriflated and aromatic products. Anthracene vinyl triflate 3e
was our lowest-yielding closure at 30%; while GC/MS analysis
1
0 min. After 10 min the pressure vessel was heated with stirring in an
oil bath at 110 °C for 20−26 h. Upon completion, the reaction mixture
was cooled to room temperature, diluted with dichloromethane, and
poured into a separatory funnel, where the organic layer was washed
three times with 1 M HCl. The organic layer was separated, dried over
anhydrous magnesium sulfate, filtered, and concentrated under
reduced pressure. Purification of the residue was accomplished by
column chromatography using silica gel with hexanes and ethyl acetate
as the eluent.
1
of the crude reaction mixture showed only 4e and 4e-2, H
NMR analysis of this arene−vinyl triflate coupling showed a
plethora of other side products. We believe that the low yield
can be attributed to the same steric issue seen in the failed
cross-coupling of 9-bromoanthracene (1f). We believe that the
closure of 3e to 4e is sterically encumbered by the hydrogen in
the 8-position of anthracene, which then encourages the
formation of side products.
2
-(Naphthalen-1-yl)cyclohexanone (2a). The reaction was run
with S-Phos as the ligand. Purification was accomplished with a 10/1
hexanes/ethyl acetate solvent mixture, which yielded 292 mg (65%) of
1
a white solid: mp 71−74 °C; H NMR (400 MHz, CDCl ) δ 7.90−
3
7
.86 (m, 1H), 7.80 (d, J = 8.3, 1H), 7.76−7.72 (m, 1H), 7.51−7.45
(
m, 3H), 7.38 (d, J = 7.2, 1H), 4.38 (dd, J = 12.5, 5.3 Hz, 1H), 2.73−
2
1
1
.62 (m, 2H), 2.48−2.40 (m, 1H), 2.36−2.24 (m, 2H), 2.19−2.12 (m,
CONCLUSION
■
13
H), 2.04−1.86 (m, 2H); C NMR (100 MHz, CDCl ) δ 210.0,
3
In summary, we have developed a new efficient three-step
process to annulate polycyclic aromatic hydrocarbons (PAHs)
that has been used to create structurally diverse tetrahy-
droindenoannulated PAHs. Our process utilizes a palladium-
catalyzed cross-coupling of brominated aromatic compounds
with cyclohexanone to yield α-arylated ketones. These ketones
can be regioselectively enolized with potassium tert-butoxide
and captured by triflic anhydride to give regiospecific vinyl
trfilates in good to excellent yields. These vinyl triflates can
then undergo an intramolecular palladium-catalyzed arene−
vinyl triflate coupling reaction to form tetrahydroindenoannu-
lated PAHs that can be run on a preparative scale. This process
provides access to PAHs with saturated rings that under current
chemical methods would be difficult to produce in an efficient
manner and could be used as an alternate route to various
PAHs.
35.2, 133.8, 131.8, 129.0, 127.6, 125.9, 125.4, 125.37, 125.34, 123.30,
−1
53.4, 42.7, 34.3, 27.9, 26.0; IR (KBr) 1708 cm (CO); HRMS (EI,
+
m/z) calcd for C H O (M ) 224.1201, found 224.1202.
16
16
2-(Phenanthren-9-yl)cyclohexanone (2b). The reaction was run
with S-Phos as the ligand. Purification was accomplished with a 10/1
hexanes/ethyl acetate solvent mixture, which yielded 351 mg (64%) of
1
a white solid: mp 145−148 °C; H NMR (400 MHz, CDCl ) δ 8.76
3
(
d, J = 8.0, 1H), 8.68 (d, J = 8.1 Hz, 1H), 7.86 (dd, J = 7.8, 1.6 Hz,
1
H), 7.75 (dd, J = 8.2, 1.4 Hz, 1H), 7.70−7.54 (m, 5H), 4.41 (dd, J =
1
2.5, 5.1 Hz, 1H), 2.78−2.63 (m, 2H), 2.59−2.49 (m, 1H), 2.48−2.35
(
m, 1H), 2.35−2.27 (m, 1H), 2.25−2.16 (m, 1H), 2.08−1.89 (m, 2H);
13
C NMR (100 MHz, CDCl ) δ 210.2, 133.6, 131.5, 130.9, 130.7,
3
1
30.0, 128.5, 126.6, 126.5, 126.4, 126.10, 126.08, 124.0, 123.4, 122.4,
−1
53.6, 42.8, 33.9, 28.1, 26.0; IR (KBr) 1704 cm (CO); HRMS (EI,
+
m/z) calcd for C20
H
18O (M ) 274.1358, found 274.1371.
2
-(Pyren-1-yl)cyclohexanone (2c). The reaction was run with S-
Phos as the ligand. Purification was accomplished with a 10/1
hexanes/ethyl acetate solvent mixture, which yielded 346 mg (58%) of
1
a white solid: mp 123−125 °C; H NMR (400 MHz, CDCl ) δ 8.21
3
EXPERIMENTAL SECTION
■
(d, J = 8.0 Hz, 2H), 8.19−8.16 (m, 1H), 8.14−8.05 (m, 3H), 8.05−
7.98 (m, 2H), 7.91 (d, J = 8.0 Hz, 1H), 4.68 (dd, J = 12.6, 5.5 Hz, 1H),
2.81−2.68 (m, 2H), 2.60−2.50 (m, 1H), 2.50−2.40 (m, 1H), 2.40−
General Experimental Considerations. Anhydrous toluene,
dichloromethane, and N,N-dimethylacetamide were purchased from
Acros, and the bottles were equipped with an Acros seal. Cyclo-
hexanone and 1-bromonaphthalene were dried over anhydrous
magnesium sulfate at 100 °C for 1 h and then distilled. Cyclo-
hexanone, 1-bromonaphthalene, and 1,8-diazabicyclo[5.4.0]undec-7-
ene (DBU) were stored over molecular sieves under nitrogen. All
solvents, cyclohexanone, and 1-bromonaphthalene were purged with
nitrogen before use. Lithium chloride (anhydrous) was stored in a
glovebag under nitrogen with desiccant to keep it dry. The palladium-
catalyzed annulations were performed in a CEM Discovery Microwave
in a sealed vessel with a constant temperature of 150 °C, measured by
an external sensor, for 60 min. Proton NMR chemical shifts are
reported in ppm downfield from tetramethylsilane with deuterochloro-
form (δ 7.26 ppm) as the reference standard, unless otherwise
specified. Carbon NMR shifts are reported in ppm downfield from
tetramethylsilane with deuterochloroform (δ 77.16 ppm) as the
reference standard. For column chromatography, silica gel 32−63 μm
was used. High-resolution mass spectra (HRMS) were measured using
time-of-flight (TOF) mass spectrometry with ionization occurring
either with electron impact (EI) or liquid introduction field desorption
ionization (LIFDI).
1
3
2.29 (m, 1H), 2.27−2.14 (m, 1H), 2.14−1.91 (m, 2H); C NMR
(100 MHz, CDCl
126.6, 126.47, 126.46, 126.10, 126.08, 126.07, 124.0, 123.4, 122.4,
) δ 210.2, 133.6, 131.5, 130.9, 130.7, 130.0, 128.5,
3
−1
53.6, 42.8, 33.9, 28.1, 26.0; IR (KBr) 1704 cm (CO); HRMS (EI,
+
m/z) calcd for C22
H
18O (M ) 298.1358, found 298.1368.
2-(Acenaphthen-5-yl)cyclohexanone (2d). The reaction was run
with X-Phos as the ligand. Purification of the residue was accomplished
by column chromatography using silica gel with hexanes and ethyl
acetate (11/1) as the eluent; yielding 297 mg (59%) of a white solid:
1
mp 99−102 °C; H NMR (400 MHz, CD
Cl
2
) δ 7.50−7.43 (m, 2H),
2
7.36−7.29 (m, 3H), 4.27 (dd, J = 12.7, 5.5 Hz, 1H), 3.50−3.38 (m,
4H), 2.74−2.55 (m, 2H), 2.46−2.37 (m, 1H), 2.37−2.25 (m, 2H),
13
2.20−2.10 (m, 1H), 2.06−1.87 (m, 2H); C NMR (100 MHz,
CDCl ) δ 210.1, 146.7, 145.2, 139.5, 131.0, 130.3, 127.6, 126.9, 119.0,
3
−1
53.14, 42.5, 34.4, 30.5, 29.9, 27.8, 25.9; IR (KBr) 1708 cm (CO);
+
HRMS (EI, m/z) calcd for C H O (M ) 250.1358, found 250.1363.
18
18
2-(Anthracen-1-yl)cyclohexanone (2e). An oven-dried 10 mL
pressure vessel containing a Teflon-coated stir bar was charged with
2.0 mmol of 1-bromoanthracene (1e), Pd(OAc) (24 mg, 0.12 mmol),
2
X-Phos (140 mg, 0.30 mmol), and anhydrous Cs CO (660 mg, 2.0
2
3
General Procedure for the Synthesis of Compounds 2a−d.
An oven-dried 10 mL pressure vessel containing a Teflon-coated stir
bar was charged with 2.0 mmol of a brominated polycyclic aromatic
mmol). The tube was capped with a rubber septum equipped with a
vent needle, and it was flushed with nitrogen for 15 min.
Cyclohexanone (290 mg, 3.0 mmol) and 2.0 mL of toluene
(anhydrous) were added via a syringe through the septum. The
septum was removed under a constant nitrogen flow and capped with
a Teflon screw cap. The reaction mixture was stirred at room
hydrocarbon (PAH), Pd(OAc) (13 mg, 0.06 mmol), S-Phos (62 mg,
2
0
.15 mmol) or X-Phos (72 mg, 0.15 mmol), and anhydrous Cs CO
2 3
(
660 mg, 2.0 mmol). The tube was capped with a rubber septum
D
dx.doi.org/10.1021/jo501576e | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
temperature for 10 min. After 10 min, the pressure vessel was heated
with stirring in an oil bath at 110 °C for 72 h. Upon completion, the
reaction mixture was cooled to room temperature, diluted with
dichloromethane, and poured into a separatory funnel, where the
organic layer was washed three times with 1 M HCl. The organic layer
was separated, dried over anhydrous magnesium sulfate, filtered, and
concentrated under reduced pressure. Purification of the residue was
accomplished by column chromatography using silica gel with hexanes
and then capped with a septum. The round-bottom flask was flushed
with N for 5 min. To this mixture of solids was added 20 mL of
2
anhydrous dichloromethane via a syringe, which caused an immediate
color change. The reaction mixture was stirred at room temperature
for 10 min. An oven-dried pear-shaped flask, fitted with a septum, was
charged with 1.5 g (5.4 mmol, 0.91 mL) of triflic anhydride and 5.0
mL of anhydrous dichloromethane. After 10 min of stirring, triflic
anhydride/DCM solution was added dropwise to the reaction (via a
syringe) until the color disappeared. After the last drop of triflic
anhydride was added, the reaction mixture was stirred at room
temperature for 1 h. The reaction was poured into a separatory funnel,
diluted with dichloromethane, washed with 1 M HCl (three times),
and separated. The organic layer was dried with anhydrous magnesium
sulfate, filtered, and concentrated under reduced pressure.
and ethyl acetate (10/1) as the eluent, yielding 379 mg (69%) of a
1
white solid: mp 136−140 °C; H NMR (400 MHz, CDCl ) δ 8.46 (s,
3
1
H), 8.27 (s, 1H), 8.09−7.93 (m, 3H), 7.52−7.41 (m, 3H), 7.37 (d, J
=
6.9 Hz, 1H), 4.56 (dd, J = 12.4, 5.2 Hz, 1H), 2.84−2.65 (m, 2H),
2
1
1
1
.56−2.45 (m, 1H), 2.44−2.28 (m, 2H), 2.25−2.14 (m, 1H), 2.12−
.90 (m, 2H); 13C NMR (100 MHz, CDCl ) δ 210.2, 135.2, 132.1,
3
31.5, 131.2, 130.4, 128.5, 128.0, 127.8, 127.3, 125.39, 125.38, 124.8,
Purification was accomplished by column chromatography using
silica gel with a 9/1 hexanes/ethyl acetate solvent mixture, which
−1
24.7, 121.8, 53.4, 42.8, 34.3, 28.1, 26.0; IR (KBr) 1699 cm (C
+
1
O); HRMS (EI, m/z) calcd for C H O (M ) 274.1358, found
yielded 756 mg (72%) of a colorless tacky solid: H NMR (400 MHz,
20
18
2
74.1357.
CD
4H), 2.66−2.45 (m, 4H), 2.02 (p, J = 6.0 Hz, 2H), 1.88 (p, J = 5.9 Hz,
2H); 13C NMR (100 MHz, CDCl
) δ 146.4, 146.3, 144.6, 139.4,
130.1, 130.0, 128.9, 128.0, 127.7, 120.0, 119.4, 118.8, (CF , 122.8,
119.6, 116.4, 113.4), 31.9, 30.5, 30.1, 27.9, 23.3, 22.2; HRMS (EI, m/
2 2
Cl ) δ 7.54−7.47 (m, 2H), 7.39−7.28 (m, 3H), 3.50−3.40 (m,
General Procedure for the Synthesis of Compounds 3a−e.
An oven-dried 20 mL scintillation vial containing a Teflon-coated stir
bar was charged with 0.5 mmol of one of the arylated ketones 2a−e
and 168 mg (1.5 mmol) of potassium tert-butoxide and then capped
3
3
+
with a septum. The vial was flushed with N for 5 min. To this mixture
z) calcd for C19H F O S (M ) 382.0851, found 382.0841.
17 3 3
2
of solids was added 8.0 mL of anhydrous dichloromethane (DCM) via
a syringe, which caused an immediate color change. The reaction
mixture was stirred at room temperature for 10 min. After 10 min of
stirring, triflic anhydride was added dropwise (via a syringe) until the
color disappeared (ca. 0.17 mL, 1.0 mmol). After the last drop of triflic
anhydride was added, the reaction mixture was stirred at room
temperature for 1 h. The reaction mixture was poured into a
separatory funnel, diluted with dichloromethane, washed with 1 M
HCl (three times), and separated. The organic layer was dried with
anhydrous magnesium sulfate, filtered, and concentrated under
reduced pressure. Purification was accomplished by silica gel
chromatography with hexanes and ethyl acetate or DCM as the eluent.
2-(Anthracen-1-yl)cyclohex-1-en-1-yl Trifluoromethanesulfonate
(
3e). Purification was accomplished with a 1/1 hexanes/DCM solvent
1
mixture, which yielded 169 mg (83%) of a pale yellow tacky solid: H
NMR (400 MHz, chloroform-d) δ 8.49 (s, 1H), 8.35 (s, 1H), 8.12−
8
.00 (m, 3H), 7.58−7.47 (m, 3H), 7.37 (d, J = 6.7 Hz, 1H), 2.81−2.61
(m, 3H), 2.61−2.49 (m, 1H), 2.20−2.04 (m, 2H), 2.03−1.89 (m, 2H);
13
C NMR (100 MHz, CDCl ) δ 145.0, 134.8, 131.8, 131.7, 131.6,
3
130.6, 128.8, 128.6, 128.4, 128.0, 127.0, 125.6, 125.5, 125.4, 124.6,
123.4, (CF , 119.5, 116.3), 31.9, 27.9, 23.3, 22.2; HRMS (EI, m/z)
calcd for C21
3
+
H F O S (M ) 406.0851, found 406.0872.
17 3 3
General Procedure for the Synthesis of Compounds 4a−e.
Vinyl triflates 3a−e were transferred to an oven-dried 15 mL pear-
shaped flask with anhydrous dichloromethane. The solvent was
removed under reduced pressure, and the flask was kept under vacuum
for at least 5 h. After 5 h the flask was fitted with a septum and flushed
with nitrogen for 10 min. In a glovebag (that had been evacuated and
filled with dry high-purity nitrogen three times) a 10 mL oven-dried
CEM Corporation microwave vessel was charged with 10 mol % of
2
-(Naphthalen-1-yl)cyclohex-1-en-1-yl Trifluoromethanesulfo-
nate (3a). Purification was accomplished with a 9/1 hexanes/ethyl
acetate solvent mixture, which yielded 280 mg (85%) of a white solid:
1
mp 59−61 °C; H NMR (400 MHz, CDCl ) δ 7.96−7.89 (m, 1H),
3
7
.87 (d, J = 8.2 Hz, 1H), 7.85−7.79 (m, 1H), 7.60−7.50 (m, 3H), 7.38
(
2
dd, J = 7.0, 1.2 Hz, 1H), 2.73−2.58 (m, 3H), 2.57−2.46 (m, 1H),
13
.10−2.00 (m, 2H), 1.97−1.86 (m, 2H); C NMR (100 MHz,
Pd(PCy ) Cl and 3.0 mol equiv of LiCl (anhydrous) and the vessel
3 2 2
CDCl ) δ 144.8, 134.7, 133.7, 130.5, 128.5, 128.3, 126.2, 125.9, 125.3,
was capped with a CEM septum pressure cap, removed from the
glovebag, and kept under nitrogen. The pear-shaped flask containing
the vinyl triflate was charged with 2.0 mL of anhydrous N,N-
dimethylacetamide (DMAc) (that had been purged with dry nitrogen
for 20 min) under nitrogen via a syringe. When all of the vinyl triflate
was dissolved, this mixture was transferred to the microwave vessel
along with 2.0 mol equiv of anhydrous 1,8-diazabicyclo[5.4.0]undec-7-
ene (DBU) via a syringe and the reaction mixture was stirred at room
temperature for 10 min. After 10 min, the reaction mixture was
subjected to microwave irradiation in a CEM Discoverer Microwave
Unit at a temperature of 150 °C with a maximum power of 200 W for
1 h. Upon completion, the vessel was removed from the microwave
and the reaction mixture was diluted with dichloromethane and
poured into a separatory funnel, where it was rinsed (three times) with
1 M HCl. The organic layer was separated, dried with anhydrous
magnesium sulfate, filtered, and concentrated under reduced pressure.
The crude product was purified either with flash column
chromatography or preparative TLC with hexanes and ethyl acetate
or DCM as the eluent.
3
1
24.8, (CF , 122.8, 119.6, 116.4, 113.2), 32.0, 27.9, 23.2, 22.1; HRMS
3
+
(
EI, m/z) calcd for C H F O S (M ) 356.0694, found 356.0703.
17 15 3 3
2
-(Phenanthren-9-yl)cyclohex-1-en-1-yl Trifluoromethanesulfo-
nate (3b). Purification was accomplished with a 10/1 hexanes/ethyl
acetate solvent mixture, which yielded 166 mg (88%) of a white solid:
1
mp 110−113 °C; H NMR (400 MHz, CDCl ) δ 8.78 (d, J = 8.1 Hz,
3
1
H), 8.73 (d, J = 8.4 Hz, 1H), 7.94 (d, J = 7.7 Hz, 1H), 7.90 (d, J = 7.9
Hz, 1H), 7.75−7.61 (m, 5H), 2.78−2.59 (m, 4H), 2.59−2.44 (m, 1H),
1
3
2
.16−1.97 (m, 2H), 1.98−1.82 (m, 2H). C NMR (100 MHz,
CDCl ) δ 145.1, 133.3, 131.3, 130.6, 130.5, 130.1, 129.4, 128.7, 126.9,
3
1
26.80, 126.78, 126.70, 126.66, 125.5, 123.1, 122.6, (CF , 122.7, 119.6,
3
1
16.4, 113.2), 31.9, 27.9, 23.3, 22.1; HRMS (EI, m/z) calcd for
+
C H F O S (M ) 406.0851, found 406.0866.
2
1
17
3
3
2
-(Pyren-1-yl)cyclohex-1-en-1-yl Trifluoromethanesulfonate (3c).
Purification was accomplished with a 1/1 hexanes/DCM solvent
mixture, which yielded 150 mg (70%) of a white solid: mp 123−125
1
°
(
4
C; H NMR (400 MHz, CDCl ) δ 8.28−8.18 (m, 3H), 8.17−8.08
3
m, 3H), 8.07−7.99 (m, 2H), 7.84 (d, J = 7.9 Hz, 1H), 2.76−2.62 (m,
13
H), 2.16−2.06 (m, 2H), 2.04−1.93 (m, 2H); C NMR (100 MHz,
7,8,9,10-Tetrahydrofluoranthene (4a). Arene−vinyl triflate cou-
pling was run with 150 mg (0.42 mmol) of vinyl triflate 3a, 31 mg
(0.042 mmol, 10 mol %) of Pd(PCy ) Cl , 54 mg (1.3 mmol, 3.0
3 2 2
equiv) of LiCl, and 130 mg (0.84 mmol, 2.0 equiv) of DBU.
CDCl ) δ 145.2, 132.1, 131.3, 131.0, 130.9, 128.0, 127.8, 127.6, 127.4,
3
1
26.1, 126.0, 125.4, 125.2, 124.9, 124.81, 124.76, 124.3, (CF , 122.7,
3
1
19.5, 116.4, 113.2), 32.6, 28.1, 23.3, 22.2; HRMS (LIFDI, m/z) calcd
+
for C H F O S (M ) 430.0851, found 430.0861.
Purification on flash column chromatography was accomplished with
23
17
3
3
2
-(1,2-Dihydroacenaphthylen-5-yl)cyclohex-1-en-1-yl Trifluoro-
19/1 hexanes/ethyl acetate to produce 60 mg of a yellow solid in 72%
1
methanesulfonate (3d). An oven-dried 50 mL round-bottom flask
containing a Teflon-coated stir bar was charged with 0.68 g (2.7
mmol) of ketone 2d and 0.91 g (8.1 mmol) of potassium tert-butoxide
yield: mp 73−74 °C; H NMR (400 MHz, CDCl ) δ 7.73−7.67 (m,
3
1
3
2H), 7.52−7.47 (m, 4H), 2.80−2.75 (m, 4H), 1.98−1.91 (m, 4H);
NMR (100 MHz, CDCl ) δ 140.5, 136.9, 128.8, 127.7, 127.4, 126.1,
C
3
E
dx.doi.org/10.1021/jo501576e | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
+
1
20.1, 22.9, 22.8; HRMS (EI, m/z) calcd for C H (M ) 206.1096,
Notes
16
14
found 206.1093.
The authors declare no competing financial interest.
9
,10,11,12-Tetrahydrobenzo[e]acephenanthrylene (4b). Arene−
vinyl triflate coupling was run with 79 mg (0.19 mmol) of vinyl triflate
b, 14 mg (0.019 mmol, 10 mol %) of Pd(PCy ) Cl , 25 mg (0.58
mmol, 3.0 equiv) of LiCl, and 59 mg (0.39 mmol, 2.0 equiv) of DBU.
Purification on flash column chromatography was accomplished with
9/1 hexanes/ethyl acetate to produce 44 mg of a yellow solid in 88%
yield: decomposition began at 56 °C; H NMR (400 MHz, CDCl ) δ
.59 (d, J = 8.0 Hz, 1H), 8.27 (d, J = 8.1 Hz, 1H), 7.96 (d, J = 7.9 Hz,
ACKNOWLEDGMENTS
3
■
3
2
2
The authors especially thank the Roy Trout Memorial Fund for
their generous financial support of the students who completed
this work. The authors also thank Washington College and the
Hodson Summer Research Fund for additional monetary
support. We also thank Jessie McAtee for acquiring the high-
resolution mass spectra for all compounds in this study and the
National Science Foundation for its support of the purchase of
a GCT mass spectrometer (CHE-1229234).
1
1
3
8
1
2
1
1
H), 7.75 (s, 1H), 7.68−7.55 (m, 3H), 7.48 (d, J = 6.9 Hz, 1H), 2.81−
13
.76 (m, 4H), 2.00−1.92 (m, 4H); C NMR (100 MHz, CDCl ) δ
3
40.3, 140.0, 138.9, 135.8, 134.3, 130.9, 130.1, 129.4, 127.6, 126.7,
26.3, 125.3, 123.1, 121.5, 120.4, 118.7, 23.0, 22.9, 22.8, 22.7; HRMS
EI, m/z) calcd for C H (M ) 256.1252, found 256.1251.
+
(
20
16
7
,8,9,10-Tetrahydroindeno[1,2,3-cd]pyrene (4c). Arene−vinyl tri-
REFERENCES
1) (a) Berresheim, A. J.; Mu
747−1786. (b) Watson, M. D.; Fechtenko
Rev. 2001, 101, 1267−1300. (c) Wu, J.; Pisula, W.; Mu
■
flate coupling was run with 75 mg (0.17 mmol) of vinyl triflate 3c, 13
mg (0.017 mmol, 10 mol %) of Pd(PCy ) Cl , 22 mg (0.51 mmol, 3.0
equiv) of LiCl, and 52 mg (0.34 mmol, 2.0 equiv) of DBU. Purification
on preparative TLC was accomplished with 9/1 hexanes/DCM to
(
1
̈
ller, M.; Mu
̈
llen, K. Chem. Rev. 1999, 99,
3
2
2
̈
tter, A.; Mu
̈
llen, K. Chem.
̈
llen, K. Chem.
Rev. 2007, 107, 718−747. (d) Kumar, B.; Viboh, R. L.; Bonifacio, M.
C.; Thompson, W. B.; Buttrick, J. C.; Westlake, B. C.; Kim, M.-S.;
Zoellner, R. W.; Varganov, S. A.; Moerschel, P.; Teteruk, J.; Schmidt,
M. U.; King, B. T. Angew. Chemie, Int. Ed. 2012, 51, 12795−12800.
produce 42 mg of a red solid in 88% yield: decomposition began at 79
1
°
C; H NMR (400 MHz, CDCl ) δ 8.35 (d, J = 7.7 Hz, 1H), 8.22 (d, J
3
=
7.7 Hz, 1H), 8.13 (s, 1H), 8.08−8.04 (m, 2H), 8.02−7.96 (m, 2H),
13
7
.93 (d, J = 8.3 Hz, 2H), 2.95−2.93 (m, 4H), 2.04−2.01 (m, 4H);
C
(2) (a) Luo, J.; Xu, X.; Mao, R.; Miao, Q. J. Am. Chem. Soc. 2012,
NMR (100 MHz, CDCl ) δ 141.4, 139.6, 136.3, 135.4, 132.0, 130.01,
3
1
1
29.97, 129.4, 127.45, 127.39, 126.7, 126.17, 126.14, 123.8, 122.2,
134, 13796−13803. (b) Feng, C.-N.; Kuo, M.-Y.; Wu, Y.-T. Angew.
Chem., Int. Ed. 2013, 52, 7791−7794. (c) Miller, R. W.; Duncan, A. K.;
Schneebeli, S. T.; Gray, D. L.; Whalley, A. C. Chem. Eur. J. 2014, 20,
3705−3711.
(3) (a) Jasti, R.; Bhattacharjee, J.; Neaton, J. B.; Bertozzi, C. R. J. Am.
Chem. Soc. 2008, 130, 17646−17647. (b) Sisto, T. J.; Golder, M. R.;
Hirst, E. S.; Jasti, R. J. Am. Chem. Soc. 2011, 133, 15800. (c) Xia, J.;
Jasti, R. Angew. Chem., Int. Ed. 2012, 51, 2474. (d) Sisto, T. J.; Jasti, R.
Synlett 2012, 23, 483. (e) Sisto, T. J.; Tian, X.; Jasti, R. J. Org. Chem.
2012, 77, 5857. (f) Darzi, E. R.; Sisto, T. J.; Jasti, R. J. Org. Chem.
2012, 77, 6624. (g) Evans, P. E.; Darzi, E. R.; Jasti, R. Nat. Chem.
2014, 6, 404.
(4) Fullerenes: (a) Kroto, H. W.; Heath, J. R.; O’Brien, S. C.; Curl, R.
F.; Smalley, R. E. Nature 1985, 318, 162−163. (b) Taylor, R.; Hare, J.
P.; Abdul-Sada, A. K.; Kroto, H. W. J. Chem. Soc. Chem. Commun.
1990, 1423−1425. (c) Boorum, M. M.; Vasil’ev, Y. V.; Drewello, T.;
Scott, L. T. Science 2001, 294, 828−831. (d) Scott, L. T.; Boorum, M.
M.; McMahon, B. J.; Hagen, S.; Mack, J.; Blank, J.; Wegner, H.; de
Meijere, A. A. Science 2002, 295, 1500−1503. (e) Scott, L. T. Angew.
Chem., Int. Ed. 2004, 43, 4994−5007.
21.6, 120.1, 119.2, 23.6, 23.0, 23.00, 22.97. HRMS (EI, m/z) calcd for
+
C H (M ) 280.1252, found 280.1259.
2
2
16
1,2,5,6,7,8-Hexahydrocyclopenta[cd]fluoranthene (4d). Arene−
vinyl triflate coupling was run with 756 mg (1.98 mmol) of vinyl
triflate 3d, 223 mg (0.198 mmol, 10 mol %) of Pd(PCy ) Cl , 384 mg
3
2
2
(
5.94 mmol, 3.0 equiv) of LiCl, 919 mg (6.04 mmol, 2.0 equiv) of
DBU, and 5.0 mL of anhydrous DMAc. Purification on flash column
chromatography was accomplished with 19/1 hexanes/ethyl acetate to
produce 355 mg of a yellow solid in 77% yield: decomposition began
1
at 100 °C; H NMR (400 MHz, chloroform-d) δ 7.53 (d, J = 6.8 Hz,
2
1
1
H), 7.32 (d, J = 6.7 Hz, 2H), 3.47 (s, 4H), 2.86−2.80 (m, 4H), 1.95−
.90 (m, 4H); 13C NMR (100 MHz, CDCl ) δ 145.1, 136.5, 136.2,
3
34.6, 127.2, 122.1, 120.1, 32.3, 23.7, 23.1; HRMS (EI, m/z) calcd for
+
C H (M ) 232.1252, found 232.1244.
1
8
16
1,2,3,4-Tetrahydrobenzo[a]aceanthrylene (4e). Arene−vinyl tri-
flate coupling was run with 75 mg (0.18 mmol) of vinyl triflate 3e, 13
mg (0.018 mmol, 10 mol %) of Pd(PCy ) Cl , 23 mg (0.54 mmol, 3.0
equiv) of LiCl, and 55 mg (0.36 mmol, 2.0 equiv) of DBU. Purification
on preparative TLC was accomplished with 9/1 hexanes/DCM to
3
2
2
produce 14 mg of a red solid in 30% yield: decomposition began at 66
(5) Hemifullerenes: (a) Barth, W. E.; Lawton, R. G. J. Am. Chem. Soc.
1966, 88, 380−381. (b) Rabideau, P. W.; Abdourazak, A. H.; Folsom,
H. E.; Marcinow, Z.; Sygula, A.; Sygula, R. J. Am. Chem. Soc. 1994, 116,
7891−7892. (c) Ansems, R. B. M.; Scott, L. T. J. Am. Chem. Soc. 2000,
122, 2719−2724. (d) Wu, Y.-T.; Siegel, J. S. Chem. Rev. 2006, 106,
4843−4867.
1
°
C; H NMR (400 MHz, CDCl ) δ 8.38 (d, J = 8.7 Hz, 1H), 8.32 (s,
3
1
H), 8.04 (d, J = 8.6 Hz, 1H), 7.87 (d, J = 8.3 Hz, 1H), 7.59 (d, J = 6.5
Hz, 1H), 7.55−7.47 (m, 2H), 7.43−7.36 (m, 1H), 3.25 (tt, J = 6.0, 2.8
Hz, 2H), 2.85 (tt, J = 5.8, 2.7 Hz, 2H), 2.09−2.00 (m, 2H), 2.00−1.93
(
m, 2H); 13C NMR (100 MHz, CDCl ) δ 140.5, 138.4, 135.2, 135.0,
3
1
1
34.6, 130.6, 129.1, 127.0, 126.9, 126.9, 126.8, 126.1, 126.0, 124.3,
(6) Scott, L. T.; Jackson, E. A.; Zhang, Q.; Steinberg, B. D.; Bancu,
M.; Li, B. J. Am. Chem. Soc. 2012, 134, 107−110.
24.1, 121.3, 26.5, 23.6, 22.9, 22.5; HRMS (EI, m/z) calcd for C H
20
16
+
(
M ) 256.1252, found 256.1246.
(7) (a) Wu, J.; Pisula, W.; Mullen, K. Chem. Rev. 2007, 107, 718−
̈
7
47. (b) Gunes, S.; Neugebauer, H.; Sariciftci, N. S. Chem. Rev. 2007,
07, 1324−1338. (c) Li, C.; Liu, M.; Pschirer, N. G.; Baumgarten, M.;
1
ASSOCIATED CONTENT
■
̈
Mullen, K. Chem. Rev. 2010, 110, 6817−6855.
* Supporting Information
S
(8) (a) Brown, R. F. C. Pyrolytic Methods in Organic Chemistry:
Text, figures, tables, and CIF files giving H and 13C NMR
spectra for all compounds and crystal structure data for
compounds 2a,b,d. This material is available free of charge via
the Internet at http://pubs.acs.org.
1
Application of Flow and Flash Vacuum Pyrolytic Techniques; Academic
Press: New York, 1980. (b) Tsefrikas, V. M.; Scott, L. T. Chem. Rev.
2
(
8
(
006, 106, 4868−4884.
9) (a) Cho, B. P.; Harvey, R. G. Tetrahedron Lett. 1987, 28, 861−
64. (b) Cho, B. P.; Harvey, R. G. J. Org. Chem. 1987, 52, 5668−5678.
10) (a) Rice, J. E.; Cai, Z. W. J. Org. Chem. 1993, 58, 1415−1424.
(b) Rice, J. E.; Cai, Z.; He, Z.; LaVoie, E. J. J. Org. Chem. 1995, 60,
AUTHOR INFORMATION
■
8
101−8104. (c) Rice, J. E.; Cai, Z. Tetrahedron Lett. 1992, 33, 1675−
Corresponding Author
1
678.
*
E-mail for A.W.A.: aamick2@washcoll.edu.
(11) (a) Reisch, H. A.; Bratcher, M. S.; Scott, L. T. Org. Lett. 2000, 2,
Author Contributions
1
427−1430. (b) Wegner, H. A.; Scott, L. T.; de Meijere, A. J. Org.
§
These authors contributed equally.
Chem. 2003, 68, 883−887. (c) Wegner, H. A.; Reisch, H.; Rauch, K.;
F
dx.doi.org/10.1021/jo501576e | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
Demeter, A.; Zachariasse, K. A.; de Meijere, A.; Scott, L. T. J. Org.
Chem. 2006, 71, 9080−9087. (d) Jackson, E. A.; Steinberg, B. D.;
Bancu, M.; Wakamiya, A.; Scott, L. T. J. Am. Chem. Soc. 2007, 129,
4
84−485. (e) Steinberg, B. D.; Jackson, E. A.; Filatov, A. S.;
Wakamiya, A.; Petrukhina, M. A.; Scott, L. T. J. Am. Chem. Soc. 2009,
1
2
31, 10537−10545. (f) Quimby, J.; Scott, L. T. Adv. Synth. Catal.
009, 351, 1009−1013. (g) Eliseeva, M. N.; Scott, L. T. J. Am. Chem.
Soc. 2012, 134, 15169−15172.
(
12) (a) Hamann, B. C.; Hartwig, J. F. J. Am. Chem. Soc. 1997, 119,
1
1
2382−12383. (b) Palucki, M.; Buchwald, S. L. J. Am. Chem. Soc.
997, 119, 11108−11109. (c) Fox, J. M.; Huang, X.; Chieffi, A.;
Buchwald, S. L. J. Am. Chem. Soc. 2000, 122, 1360−1370. (d) Culkin,
D. A.; Hartwig, J. F. Acc. Chem. Res. 2003, 36, 234−245.
(
13) (a) Scott, W. J.; Crisp, G. T.; Stille, J. K. J. Am. Chem. Soc. 1984,
1
2
06, 4630−4632. (b) Scott, W. J.; McMurry, J. E. Acc. Chem. Res. 1988,
1, 47−54. (c) Willis, M. C.; Taylor, D.; Gillmore, A. T. Chem.
Commun. 2003, 2222−2223.
(
2
(
14) Peng, L. Ph.D. Thesis, Boston College, Chestnut Hill, MA,
006.
15) (a) McMurry, J. E.; Scott, W. J. Tetrahedron Lett. 1983, 24,
9
79−982. (b) Wulff, W. D.; Peterson, G. A.; Bauta, W. E.; Chan, K.;
Faron, K. L.; Gilbertson, S. R.; Kaesler, R. W.; Yang, D. C.; Murray, C.
K. J. Org. Chem. 1986, 51, 277−279.
(
16) Kraft, M. E.; Holton, R. A. Tetrahedron Lett. 1983, 24, 1345−
1
348.
17) (a) Imai, H.; Nishiguchi, T.; Tanaka, M.; Fukuzumi, K. J. Org.
(
Chem. 1977, 42, 2309−2313. (b) Ben-David, Y.; Gozin, M.; Portnov,
M.; Milstein, D. J. Mol. Catal. 1992, 73, 173−180. (c) Grushin, V. V.;
Alper, H. Chem. Rev. 1994, 94, 1047−1062.
(
18) Tojo, M.; Fukuoka, S.; Tsukube, H. J. Mol. Catal. A: Chem.
2
011, 337, 89−94.
G
dx.doi.org/10.1021/jo501576e | J. Org. Chem. XXXX, XXX, XXX−XXX