A novel organic electron donor derived from N-methylisatin

Article abstract of DOI:10.1071/CH12480

We report the reactivity of an electron donor derived from N-methylisatin on reduction by sodium amalgam. Transfer of a clear supernatant solution to iodoarenes affords the products of two-electron reduction. Reductions of sulfones, activated arenesulfonamides, and Weinreb amides are also reported.

Full text of DOI:10.1071/CH12480

RESEARCH FRONT
CSIRO PUBLISHING
Aust. J. Chem. 2013, 66, 314–322
Full Paper
http://dx.doi.org/10.1071/CH12480
A Novel Organic Electron Donor Derived
from N-Methylisatin*
A
A
A B
,
Ryan Sword, Steven O’Sullivan, and John A. Murphy
A
WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde,
295 Cathedral Street, Glasgow G1 1XL, UK.
B
Corresponding author. Email: john.murphy@strath.ac.uk
We report the reactivity of an electron donor derived from N-methylisatin on reduction by sodium amalgam. Transfer of a
clear supernatant solution to iodoarenes affords the products of two-electron reduction. Reductions of sulfones, activated
arenesulfonamides, and Weinreb amides are also reported.
Manuscript received: 21 October 2012.
Manuscript accepted: 13 November 2012.
Published online: 7 January 2013.
Reduction of organic substrates through electron transfer is
currently a hot topic in synthetic chemistry. New reagents have
been derived from ground-state metal complexes,[1] photo-
excited metal complexes,[2] ground-state organic compounds,[3]
and photoexcited organic compounds.[4]
1[5] (Scheme 1). This compound is strong enough to reduce
arenediazonium salts but is considerably weaker than the
nitrogen-containing donors 2–9, some of which are structurally
similar to TTF. For the donors 3–8,[6–13] the aromatic nature of
their oxidation products adds to the driving force for their
reactivity. Thus, loss of two electrons from donor 5 affords the
aromatic disalt 10. In contrast, donor 9 starts as an aromatic
Our interest in this area arose when we explored the reactivity
of the sulfur-containing electron donor tetrathiafulvalene (TTF)
N
N
N
N
S
S
S
S
Me2N
Me2N
NMe2
NMe2
N
N
N
N
N
N
Me2N
NMe2
Me
Me
4
1
2
3
5
Octyl
N
Bu
N
Bu
NMe2
p-tolyl
N
N
NMe2
N
NMe2
N
N
N
N
NMe2
p-tolyl
p-tolyl
NMe2
ꢁ
ꢁ
ꢀ
ꢀ
N
N
Bu
Bu
Me2N
N
N
N
X
X
Me2N
N
p-tolyl
NMe2
Me2N
NMe2
N
N
Bu
Bu
O
7
10
9
8
R
R
N
N
N
Oꢀ
ꢁ
Na/Hg, DMF
Octyl
Na
ꢁ
Oꢀ
6
O
Na
11
12
Scheme 1.
*This paper is dedicated to the memory of Professor Athel Beckwith.
Journal compilation Ó CSIRO 2013
www.publish.csiro.au/journals/ajc

Novel Organic Electron Donor Derived from N-Methylisatin
315
system, but loss of two electrons sacrifices the aromaticity as it
converts into a quinonoid dication structure.
with excess iodine and back-titration with sodium thiosulfate
showed that the green solution of the activated species trans-
ferred two electrons per molecule. Re-isolation of the material
following oxidation with iodine afforded 11 in excellent yield,
and hence we propose structure 12 for the green donor.
When added to iodoarene 13, the reaction yielded the
deiodinated arene 14 in a very good 84 % yield. To test that
the reductive reactivity was due to the reduced 1-methylisatin,
a blank reaction was conducted in its absence. Transferring the
supernatant liquid above the sodium amalgam reassuringly gave
no reduction of the iodoarene. To reinforce the easy reduction of
iodoarene 13, substrate 15 was reduced in like manner to afford
the arene 16 (80 %).
Our research has recently focussed on the reagents 2–5, all of
which, like TTF 1, have a very electron-rich alkene substituted
by two or more heteroatoms. We now wondered about the effect
of anionic heteroatom substituents on electron-rich alkenes, and
our attention focussed on isatins. Reduction of 1-methylisatin
should afford the disalt 12, where the five-membered ring
appears to be intensely electron-rich (Scheme 2). Prospective
donor 12 features an aromatic system, namely an indole; loss of
two electrons would lead back to N-methylisatin 11, which is not
aromatic, and so this should moderate the electron-donating
properties.
1-Methylisatin was formed as a red solid by reaction of isatin
with sodium hydride in DMF and then addition of iodo-
methane.[14] When 1-methylisatin was reduced with sodium
amalgam, a green, clear supernatant solution was formed. This
was clearly separate from the residual amalgam and was
transferred by cannula to the substrates and heated at 1108C
for 18 h, with results as indicated below. To check the redox
activity of the N-methylisatin, a cyclic voltammogram was
recorded (see Supplementary Material) and this showed two
quasi-reversible one-electron reductions at ꢀ0.9 and ꢀ1.9 V
relative to Ag/AgCl. To determine the stoichiometry of the
green reducing solution, an aliquot of this solution was titrated
To determine whether the reducing system had converted the
iodoarenes into aryl radicals or aryl anions (strictly speaking,
organosodium compounds), two probes were prepared. The
allyl iodoaryl ether 17,[15,16] on treatment with the reduced
green solution formed with excess amalgam from methylisatin
(3 equiv.), afforded only the de-iodinated product 23 (68 %),
whereas the iodo ester 18[8c,17] on reaction with the green
solution afforded the indanone 24 (39 %) as well as the
de-iodinated compound 25 (8 %) (Scheme 3). Cyclisation of
aryl radicals onto allyl groups as for structure 19 was pioneered
by Beckwith[15] and became a diagnostic reaction for aryl
radicals; aryl anions do not cyclise in the presence of a reactive
solvent like DMF. Similarly, cyclisation onto carboxylic esters
is a hallmark of aryl anions, whereas aryl radicals do not cyclise
onto esters.
Me
N
O
Therefore, the evidence from substrates 17 and 18 is in
favour of aryl anions being formed here. This is consistent with
the reduction potentials for aryl iodides being – 2 V versus
saturated calomel electrode,[18] whereas the standard reduction
potential E0 of aryl radicals is ,0 V.[19]
O
11 (1 mmole)
Na (2.2 mmole), Hg, DMF
Next, a set of sulfones 26–28 was prepared and reacted with
the methylisatin-derived donor solution (Scheme 4). The gem-
bissulfones 26 and 27 underwent desulfonation to their corre-
sponding anions; on workup, these were protonated to 29 and 30
in 80 and 86 % yields respectively, whereas the activated
monosulfone 28 afforded 1,1-diphenylethane 31 (79 %).
Sulfonamides 32–35 were prepared. Examples 32–34 were
successfully deprotected with the green reagent as shown in
Scheme 4 whereas 35 was left untouched. Rationalising the
selectivity seen in the reactions in Scheme 4, we have previously
shown that the reactivity of arenesulfonamides towards reduc-
tion depends on the leaving ability of the group attached to
nitrogen.[8c] When that leaving group is an indolyl group and is
ꢁ
Me
Na
N
O ꢀ
ꢀ
ꢁ
I
Na
O
12, R ꢂ Me
O(CH2)nPh
DMF, 110ꢃC, 18 h
O(CH2)nPh
13, n ꢂ 3 (0.3 mmole)
15, n ꢂ 1 (0.3 mmole)
14, n ꢂ 3, 84 %
16, n ꢂ 1, 80 %
Scheme 2.
Na ꢁ
Na ꢁ
EtO
I
I
O
.
.
Me
Me
ꢀ
eꢀ
2eꢀ
ꢀ
eꢀ
2eꢀ
CO2Et
CO2Et
O
O
O
O
O
Me
Me
O
Me
Me
22
17
19
18
.
Me
O
eꢀ
H
O
H
CO2Et
Me
Me
O
O
O
Me
Me
O
23
21
20
25
24
Scheme 3.

316
R. Sword, S. O’Sullivan, and J. A. Murphy
Me
PhO2S
Me
H
Me
PhO2S
Me
SO2Ph
N
Ph
N
H
Ph
Ts
37, 84 %
33
29, 80 %
26
27
Me
Me
N
N
H
38, 79 %
PhO2S
H
PhO2S
SO2Ph
Ts
30, 86 %
34
35
Me
Me
Ph
SO2Ph
Ph
No reaction
N
Ph
Ph
Ts
28
31, 79 %
O
O
Me
Me
N
H
N
n
n
OMe
N
N
H
Ts
32
41, n ꢂ 0, 79 %
42, n ꢂ 1, 77 %
39, n ꢂ 0
40, n ꢂ 1
36, 76 %
Scheme 4.
aniline-derived, then the nitrogen leaving group is resonance-
stabilised and the reaction is assisted by this. However, if the
nitrogen is part of a dialkylamino group such that no resonance
stabilisation of the nitrogen is available, as would happen in
substrate 35, then the cleavage is much more difficult. This is
also clearly represented in the examples shown here.
Finally, Weinreb amides 39 and 40 were prepared. These
underwent reduction with cleavage of their N–O bonds to form
amide products 41 (79 %) and 42 (77 %) respectively.[9c]
This shows that 1-methylisatin is reduced by excess sodium
amalgam to an active electron donor that reductively cleaves
iodoarenes, gem-bissulfones, activated arenesulfonamides, and
Weinreb amides. In this respect, it mimics the chemistry of the
strong electron donors 4 and 5. This reductive reactivity may at
first seem surprising, but the structural analogy of the dianion 12
with the electron-rich alkenes in the known strong electron
donors 2–5 places the newly found reactivity in context.
the ESPRC National Mass Spectrometry Service Centre, Swan-
sea, on a JLZX 102TM, VGZAB-ETM, or a VGTM micromass
instrument. Low-resolution mass spectra were recorded either
on a ThermoFinniganTM PolarisQ ion trap spectrometer (EI and
CI) or on a ThermoFinnigan LCQ DUOTM mass spectrometer
(for liquid chromatography (LC) mass spectrometry).
Column chromatography was performed using Prolabo
35–75-mm particle size silica gel 60 (200–400 mesh). Reactions
were followed using TLC on Merck silica gel 60 F254 precoated
aluminium plates. Visualisation was achieved under UVP
Mineralight UVG-11 lamp or by developing plates with metha-
nolic vanillin.
Chemical reagents used in all experiments were obtained
from commercial suppliers. DCM, THF, diethyl ether, toluene,
and hexane were dried using a Pure-Solv 400 solvent purifica-
tion system.
Electrochemical measurements were carried out using an
AutolabÒ PGSTAT302N potentiostat.
Experimental
General
1-Methylisatin 11
1H NMR spectra were recorded at 400.13 or 500.13 MHz using a
Bruker AV400, DPX400, or DRX500 spectrometer. 13C NMR
spectra were recorded at 100.6 or 125.7 MHz using a Bruker
AV400, DPX400, or DRX500 spectrometer. Multiplicities of
carbon resonances were obtained by recording J-modulated
(JMOD) 13C NMR spectra. Unless otherwise stated, NMR
spectra were recorded using deuterochloroform (CDCl3) as the
solvent, and chemical shifts are reported in parts per million
(ppm). Coupling constants, J, are reported in Hertz (Hz).
A Perkin–Elmer Spectrum One Fourier-transform (FT)-IR
spectrometer was used to record infrared spectra. Melting points
were recorded using a Gallenkamp 2C 7065 melting point
apparatus.
Under inert atmosphere, sodium hydride (60 % in mineral oil,
3.26 g, 81.56 mmol, 1.2 equiv.) was washed with dry hexane
three times and then dried under argon flow. A solution of isatin
(10.0 g, 67.97 mmol, 1.0 equiv.) in dry DMF (100 mL) was
slowly added to the sodium hydride at 08C. The reaction mixture
was stirred for 1 h at room temperature before being cooled
down to 08C. Iodomethane (5.08 mL, 81.56 mmol, 1.2 equiv.) in
dry DMF (20 mL) was slowly added to the reaction mixture. The
reaction mixture was stirred for 18 h. The solution was slowly
quenched with water (30 mL) and further diluted with water
(200 mL) and extracted with DCM (3 ꢁ 100 mL). The combined
organic layers were washed with water (3 ꢁ 100 mL), brine
(100 mL), dried over Na2SO4, and concentrated under reduced
pressure. The crude product was recrystallised from ethyl ace-
tate to afford 1-methylisatin 11 (Chart 1) as a red solid (8.42 g,
75 %), mp 127–1298C (lit.[14] 132–1348C). m/z (EIþ) 161.0469;
C9H7NO2 (Mþ) requires 161.0477. nmax (neat)/cmꢀ1 3054,
2923, 1742, 1723, 1599, 1467, 1091. dH (CDCl3, 400 MHz) 3.27
UV-visible spectra were recorded with a VARIAN Cary 50
Probe UV-visible spectrophotometer.
Mass spectra were recorded using electron ionisation (EI),
chemical ionisation (CI), or electrospray ionisation (ESI) tech-
niques. High and low resolution mass spectra were recorded at

Novel Organic Electron Donor Derived from N-Methylisatin
317
O
Table 1. Titrations with sodium thiosulfate
O
N
Titration
Volume of Na2S2O3 solution used [mL]
Me
1
13.2
12.9
12.8
12.97
11
2
3
Chart 1.
Average
mmoles of Na2S2O3 used in titration ¼ (10.599 ꢁ 0.01297) ¼ 0.137.
mmoles of unreacted I2 quenched with Na2S2O3 ¼ (0.137/2) ¼
0.0687 mmol.
‘
O
ONa
ONa
O
I2
Na/Hg
O
O
N
N
N
11
12
Scheme 5.
11
O
14
Chart 2.
(3H, s, NCH3), 6.91 (1H, d, J 7.7, ArH), 7.15 (1H, t, J 7.6, ArH),
7.61–7.65 (2H, m, ArH). dC (CDCl3, 100 MHz) 26.3 (CH3),
110.1 (CH), 117.3 (CH), 125.2 (CH), 138.5 (CH), 151.5 (C),
158.3 (C), 183.4 (C). m/z (EI)þ 161 (Mþ, 35 %), 104 (100),
78 (50).
Na2S2O3 titration against excess I2 remaining after iodine
quench of donor 12 solution is shown in Table 1.
Moles of I2 (reacted with donor 12) ¼ total I2 moles ꢀ moles
of unreacted I2 (quenched with Na2S2O3) ¼ 0.166 ꢀ 0.0687 ¼
0.0973 mmol. 0.101 mmol of donor 12 reacted with
0.0973 mmol of I2.
Generation of Donor 12 and Oxidation with Iodine:
Regeneration of 1-Methylisatin 11 to Provide
Evidence in Support of Structure 12
Two electrons are required to reduce I2 to 2Iꢀ; therefore,
donor 12 is a two-electron donor.
Under an inert atmosphere, a sodium amalgam (1 %, 50 mg Na,
5.0 g Hg) was prepared and dry DMF (15 mL) was added, fol-
lowed by 1-methylisatin (161 mg, 1.0 mmol, 1 equiv.). The
reaction mixture was stirred at room temperature for 4 h. The
green solution was then transferred by cannula to a solution of
iodine (508 mg, 2 mmol, 2 equiv.) in dry DMF (15 mL). The
reaction mixture was stirred at room temperature for 30 min, and
then quenched with saturated sodium thiosulfate (100 mL) and
extracted with ethyl acetate (2 ꢁ 50 mL). The combined organic
layers were washed with water (4 ꢁ 100 mL), brine (50 mL),
dried over Na2SO4, and concentrated under reduced pressure to
afford 1-methylisatin 11 (Scheme 5) as a red solid (147 mg,
91 %) with data matching those of the authentic material.
Standard Procedure for Reduction Applied
to (3-Phenoxypropyl)benzene 14
Under inert atmosphere, a sodium amalgam (1 %, 50 mg Na,
5.0 g Hg) was prepared and dry DMF (15 mL) was added, fol-
lowed by 1-methylisatin (161 mg, 1.0 mmol, 3 equiv.). The
reaction mixture was stirred at room temperature for 4 h. The
green solution was then transferred by cannula to 1-iodo-4-(3-
phenylpropoxy)benzene 13[9j] (113 mg, 0.3 mmol, 1 equiv.).
The reaction mixture was heated to 1108C for 18 h, then allowed
to cool to room temperature. The mixture was diluted with water
(40 mL) and extracted with ethyl acetate (3 ꢁ 20 mL). The
combined organic layers were washed with water (3 ꢁ 20 mL),
brine (20 mL), dried over Na2SO4, and concentrated under
reduced pressure. The crude product was purified by silica gel
chromatography, eluting with 0–10 % ethyl acetate/hexane, to
afford 1-(3-phenoxypropyl)benzene 14 (Chart 2) as a colourless
oil[9j] (60 mg, 84 %). m/z (ESIþ) 230.1538; C15H20NO (M þ
NH4)þ requires 230.1539. nmax (neat)/cmꢀ1 3061, 3025, 2879,
1600, 1497, 1245, 1038, 751. dH (CDCl3, 400 MHz) 2.11–2.18
(2H, m, CH2), 2.85 (2H, t, J 7.6, CH2), 4.00 (2H, t, J 6.3, OCH2),
6.92–6.99 (3H, m, ArH), 7.23–7.26 (3H, m, ArH), 7.28–7.34
(4H, m, ArH). dC (CDCl3, 100 MHz) 30.9 (CH2), 32.2 (CH2),
66.7 (CH2), 114.6 (CH), 120.6 (CH), 125.9 (CH), 128.5 (CH),
129.4 (CH), 141.6 (C), 159.0 (C). m/z (ESIþ) 212 ([M]þ, 20 %),
118 (10), 108 (13), 91 (22).
Determination of UV Spectrum of 12
Under an inert atmosphere, a sodium amalgam (1 %, 50 mg Na,
5.0 g Hg) was prepared and dry DMF (15 mL) was added, fol-
lowed by 1-methylisatin (161 mg, 1.0 mmol, 1 equiv.). The
reaction mixture was stirred at room temperature for 4 h.
A sample of the resulting green solution was diluted stepwise in
dried benzene to a concentration of 1.25 ꢁ 10ꢀ6 M. The sample
was sealed in a 1-cm2 quartz cuvette and measurements taken.
l
max (DMF/benzene) 340 nm (e 9.2 ꢁ 105), 598 nm (e 1.1 ꢁ 105).
Experiment to Determine the Number of Electrons
Transferred from Donor 12
A solution (10.10 mM) of methylisatin (57 mg, 0.354 mmol) in
DMF (35 mL) was prepared, and treated with sodium amalgam
to generate a green solution of donor 12. An aliquot (10 mL) of
this green solution was removed and reacted with an aliquot of
iodine solution (10 mL, 16.62 mM in DMF) i.e. excess iodine.
The unreacted iodine was then titrated with a solution of sodium
thiosulfate pentahydrate (10.599 mM; 526 mg in 200 mL water).
The reaction was repeated three times. The results indicated
donor 12 transferred two electrons to iodine.
Blank reaction: a blank reaction was prepared using the
procedure detailed above in the absence of 1-methylisatin.
The liquid above the amalgam was transferred to the substrate
by cannula. A 1H NMR spectrum of the crude reaction mixture
following workup identified 1-iodo-4-(3-phenylpropoxy)
benzene 14 as the only component present. 1-(3-Phenoxypropyl)
benzene was not observed.

318
R. Sword, S. O’Sullivan, and J. A. Murphy
O
O
23
16
Chart 5.
Chart 3.
O
CO2Et
I
ꢁ
O
O
O
24
25
17
Chart 6.
Chart 4.
was reacted with 1-methylisatin 11 (161 mg, 1 mmol, 3 equiv.).
The crude product was purified by silica gel chromatography,
eluting with 0–15% ethyl acetate/hexane to afford allyloxy-
benzene 23 (Chart 5) as a colourless oil (31 mg, 68 %). nmax
(neat)/cmꢀ1 3021, 2987, 2884, 1548, 795. dH (CDCl3, 500 MHz)
4.56 (2H, dm, J 6.8, OCH2), 5.31 (1H, dm, J 10.5, CHH¼CH),
5.45 (1H, dm, J 17.2, CHH¼CH), 6.05–6.15 (1H, m, CH¼CH2),
6.94–6.98 (3H, m, ArH), 7.30–7.34 (2H, m, ArH). dC (CDCl3,
100 MHz) 68.2 (CH2), 114.2 (CH2), 117.1 (CH), 120.3 (CH),
128.9 (CH), 132.9 (CH), 158.1 (C). m/z (CI) 135 ([M þ H]þ,
100 %), 122 (10), 108 (15), 94 (20), 78 (5).
Benzyloxybenzene 16
The standard procedure for reduction was applied to
1-(benzyloxy)-4-iodobenzene 15[9j] (103 mg, 0.3 mmol,
1 equiv.), which was reacted with 1-methylisatin 11 (161 mg,
1 mmol, 3 equiv.). The crude product was purified by silica gel
chromatography, eluting with 0–10 % ethyl acetate/hexane to
afford benzyloxybenzene 16 (Chart 3) as a colourless oil (49 mg,
80 %).[9j] m/z (CIþ) 185.0959; C13H13O (M þ H)þ requires
185.0961. nmax (neat)/cmꢀ1 3066, 3027, 2918, 1495, 1240, 727.
dH (CDCl3, 500 MHz) 5.11 (2H, s, OCH2), 6.99–7.04 (3H, m,
ArH), 7.28–7.33 (3H, m, ArH), 7.34–7.38 (2H, m, ArH), 7.41–
7.50 (2H, m, ArH). dC (CDCl3, 125 MHz) 69.4 (CH2),
114.4 (CH), 120.5 (CH), 127.0 (CH), 127.4 (CH), 128.1 (CH),
129.0 (CH), 136.6 (C), 158.3 (C). m/z (CI) 275 (15 %), 185
([M þ H]þ, 100).
2,2-Dimethylbenzofuran-3-one 24 and Ethyl 2-Methyl-2-
phenoxypropanoate 25
The standard procedure for reduction was applied to ethyl 2-(2-
iodophenoxy)-2-methylpropanoate 18[8b] (111 mg, 0.3 mmol,
1 equiv.). This was reacted with 1-methylisatin 11 (161 mg,
1 mmol, 3 equiv.). The crude product was purified by silica gel
chromatography, eluting with 0–10 % diethyl ether/pentane to
afford 2,2-dimethylbenzofuran-3-one 24 (19 mg, 36 %) and
2-methyl-2-phenoxypropanoate 25 (Chart 6) (5.5 mg, 8 %) as
colourless oils.
24 m/z (ESIþ) 163.0735; C10H10O2 requires (M þ H)þ
163.0754. nmax (neat)/cmꢀ1 2986, 2934, 1727, 1618, 1154,
760. dH (CDCl3, 500 MHz) 1.48 (6H, s, 2 ꢁ CH3), 7.08 (2H,
m, ArH), 7.61–7.65 (1H, td, J 7.6, 1.4, ArH), 7.68 (1H, d, J 7.1,
ArH). dC (CDCl3, 125 MHz) 22.5 (CH3), 87.3 (C), 113.1 (CH),
119.0 (C), 121.2 (CH), 124.4 (CH), 137.6 (CH), 170.4 (C),
203.9 (C).
25 m/z (ESIþ) 226.1440; C12H20NO3 (M þ NH4)þ requires
226.1438. nmax (neat)/cmꢀ1 3064, 2989, 2940, 1733, 1580,
1495, 760. dH (CDCl3, 500 MHz) 1.28 (3H, t, J 7.1, CH3),
1.64 (6H, s, CH3), 4.27 (2H, q, J 7.1, CH2), 6.88–6.90 (3H, m,
ArH), 6.99–7.03 (2H, m, ArH). dC (CDCl3) 14.2 (CH3), 25.5
(CH3), 61.5 (CH2), 79.1 (C), 119.2 (CH), 122.2 (CH), 129.9
(CH), 155.6 (C), 174.4 (CO). m/z (EIþ) 208 ([M]þ, 100 %), 135
(100), 94 (56), 66 (14).
1-(Allyloxy)-2-iodobenzene 17[16]
Sodium carbonate (0.7 g, 6.6 mmol, 3.0 equiv.) was added to a
stirred solution of 2-iodophenol (0.49 g, 2.2 mmol, 1.0 equiv.) in
dry DMF (20 mL). Allyl bromide (0.23 mL, 2.67 mmol,
1.2 equiv.) was then slowly added to the reaction mixture. The
reaction mixture was heated to 808C and stirred for 18 h. The
reaction mixture was allowed to cool to room temperature and
DMF removed under reduced pressure. The crude mixture was
diluted with water (40 mL) and extracted with diethyl ether
(3 ꢁ 20 mL). The combined organic layers were washed with
water (3 ꢁ 20 mL), brine (20 mL), dried over Na2SO4, and
concentrated under reduced pressure. The crude product was
purified by silica gel chromatography, eluting with 0–10 %
diethyl ether/light petroleum, to afford 1-(allyloxy)-2-
iodobenzene 17 (Chart 4) as a yellow oil (497 mg, 86 %).[16] m/z
(CIþ) 260.9764; C9H10IO (M þ H)þ requires 260.9771. nmax
(neat)/cmꢀ1 3060, 2918, 2863, 1580, 1468, 1246. dH (CDCl3,
500 MHz) 4.62 (2H, d, J 4.8, OCH2), 5.34 (1H, dd, J 10.6, 1.5,
CH¼CHH), 5.56 (1H, dd, J 17.2, 1.5, CH¼CHH), 6.05–6.14
(1H, m, CH¼CH2), 6.73 (1H, td, J 7.4, 1.4, ArH), 6.83 (1H, dd,
J 7.4, 1.4, ArH), 7.32 (1H, td, J 7.4, 1.4, ArH), 7.81 (1H, dd,
J 7.4, 1.4, ArH). dC (CDCl3, 125 MHz) 69.2 (CH2), 86.2 (C),
112.1 (CH2), 117.1 (CH), 122.2 (CH), 128.9 (CH), 132.1 (CH),
139.1 (CH), 156.6 (C). m/z (CIþ) 260 ([M þ H]þ, 100 %), 219
(20), 94 (15), 78 (25).
Isopropylsulfonylbenzene 29
The standard procedure for reduction was applied to 1-(2-
(phenylsulfonyl)propan-2-ylsulfonyl)benzene 26[8c] (97 mg,
0.3 mmol, 1 equiv.). This was reacted with 1-methylisatin 11
(161 mg, 1 mmol, 3 equiv.). The crude product was purified by
silica gel chromatography, eluting with 0–20 % ethyl acetate/
hexane to afford isopropylsulfonylbenzene 29 (Chart 7) as a
yellow oil (44 mg, 80 %). m/z (EIþ) 184.0554; C9H12O2S (M)þ
requires 184.0558. nmax (neat)/cmꢀ1 3060, 2978, 2929, 1446,
Allyloxybenzene 23
The standard procedure for reduction was applied to
1-(allyloxy)-2-iodobenzene 17 (87 mg, 0.3 mmol, 1 equiv.). This

Novel Organic Electron Donor Derived from N-Methylisatin
319
Me
Me
S
N
S
O
O
O
O
29
Chart 7.
Me
32
S
O
O
Chart 10.
30
Chart 8.
Me
N
O
S
O
Me
Me
31
34
Chart 11.
Chart 9.
4-Methyl-N,N-diphenylbenzenesulfonamide 32
1306, 1144. dH (CDCl3, 400 MHz) 1.29 (6H, d, J 6.8, 2 ꢁ CH3),
3.20 (1H, septet, J 6.8, CH(CH3)2), 7.57 (2H, t, J 7.4, ArH), 7.66
(1H, t, J 7.4, ArH), 7.88 (2H, d, J 7.4, ArH). dC (CDCl3,
100 MHz) 15.2 (CH3), 55.0 (CH), 128.5 (CH), 133.1 (CH),
136.5 (C). m/z (EIþ) 184 ([M]þ, 10 %), 142 (22), 78 (100),
51 (18).
To a solution of 1,2-diphenylamine (2.0 g, 11.81 mmol,
1.0 equiv.) in chloroform (30 mL) at 08C, pyridine (1.93 mL,
23.63 mmol, 2.0 equiv.) was added.
A
solution of
p-toluenesulfonyl chloride (2.49 g, 17.72 mmol, 1.5 equiv.) in
chloroform (15 mL) was slowly added. The reaction mixture
was stirred for 48 h. Water (30 mL) and diethyl ether
(3 ꢁ 30 mL) were added and the combined organic layers were
washed with 2 M HCl (5 mL), 5 % NaHCO3 (5 mL), water
(3 ꢁ 20 mL), brine (20 mL), dried over Na2SO4, and concen-
trated under reduced pressure. The crude product was
recrystallised from methanol to afford 4-methyl-N,N-
diphenylbenzenesulfonamide 32 (Chart 10) as colourless
crystals (3.20 g, 84 %), mp 142–1438C (lit.[20] 138–1398C).
m/z (ESIþ) 324.1052; C19H18NO2S (M þ H)þ requires
324.1053. nmax (neat)/cmꢀ1 3049, 2992, 2876, 1590, 1360,
1121. dH (CDCl3, 400 MHz) 2.44 (3H, s, CH3), 7.26–7.32 (12H,
m, ArH), 7.59 (2H, d, J 6.6, ArH). dC (CDCl3, 100 MHz) 21.6
(CH3), 127.4 (CH), 127.8 (CH), 128.3 (CH), 129.2 (CH), 129.5
(CH), 137.6 (C), 141.6 (C), 143.6 (C). m/z (ESIþ) 664
([2M þ NH4]þ) (35 %), 341 ([M þ NH4]þ) (75), 324 ([M þ H]þ,
100), 169 (45).
Cyclopentylsulfonylbenzene 30
The standard procedure for reduction was applied to 1,1-
diphenylsulfonylcyclopentane 27[8c] (105 mg, 0.3 mmol,
1 equiv.). This was reacted with 1-methylisatin 11 (161 mg,
1 mmol, 3 equiv.). The crude product was purified by silica gel
chromatography, eluting with 0–20 % ethyl acetate/hexane to
afford cyclopentylsulfonylbenzene 30 (Chart 8) as an orange oil
(54 mg, 86 %). m/z (ESIþ) 228.1055; C11H18NO2S (M þ NH4)þ
requires 228.1053. nmax (neat)/cmꢀ1 3048, 2986, 1457, 1331,
1160, 975. dH (CDCl3, 500 MHz) 1.60–1.65 (2H, m, CH2), 1.77–
1.91 (4H, m, CH2CH2), 2.07–2.10 (2H, m, CH2), 3.50 (1H,
quintet, J 7.9, CH), 7.57 (2H, tm, J 7.4, ArH), 7.65 (1H, tm, J 7.4,
ArH), 7.92 (2H, dd, J 7.4, 1.3, ArH). dC (CDCl3, 125 MHz) 25.8
(CH2), 27.2 (CH2), 64.2 (CH), 128.4 (CH), 129.1 (CH), 133.4
(CH), 139.1 (C). m/z (ESIþ) 443 (13 %), 352 (20), 228 ([M þ
NH4]þ, 100).
2-Methyl-1-tosylindoline 34
1,1-Diphenylethane 31
Aqueous sodium hydroxide (50 %, 15.25 g, 190 mmol,
13 equiv.) was added to a solution of 2-methylindoline (2.0 g.
15.03 mmol, 1.0 equiv.) and tetrabutylammonium hydrogen
sulfate (510 mg, 1.5 mmol, 0.1 equiv.) in DCM (150 mL).
A solution of p-toluenesulfonyl chloride (3.80 g, 20 mmol,
1.3 equiv.) in DCM (15 mL) was added slowly to the reaction
mixture. The mixture was stirred for 16 h at room temperature.
The mixture was poured into water (200 mL) and extracted with
ethyl acetate (3 ꢁ 50 mL). The combined organic layers were
washed with water (3 ꢁ 50 mL), brine (50 mL), dried over
Na2SO4, and concentrated under reduced pressure. The crude
mixture was purified by silica gel chromatography, eluting with
0–10 % ethyl acetate/light petroleum to afford 2-methyl-1-
tosylindoline 34 (Chart 11) as a red solid (3.36 g, 78 %),
The standard procedure for reduction was applied to (1-
(phenylsulfonyl)ethane-1,1-diyl)dibenzene 28[8c] (96 mg,
0.3 mmol, 1 equiv.). This was reacted with 1-methylisatin 11
(161 mg, 1 mmol, 3 equiv.). The crude product was purified by
silica gel chromatography, eluting with neat hexane to afford
1,1-diphenylethane 31 (Chart 9) as a colourless oil (43 mg,
79 %). m/z (EIþ) 182.1091; C14H14 (M)þ requires 182.1096.
nmax (neat)/cmꢀ1 3061, 3026, 2968, 2927, 2873, 1597, 1493,
698. dH (CDCl3, 400 MHz) 1.74 (3H, d, J 7.2, CH3), 4.25 (1H, q,
J 7.2, CH), 7.25–7.39 (10H, m, ArH). dC (CDCl3, 100 MHz)
22.1 (CH3), 45.1 (CH), 126.3 (CH), 127.8 (CH), 128.6 (CH),
146.6 (C). m/z (EIþ) 182 ([M]þ, 89 %), 167 (100), 152 (52),
77 (48), 51 (34).

320
R. Sword, S. O’Sullivan, and J. A. Murphy
O
N
S
N
H
O
36
Chart 13.
Me
35
Chart 12.
N
H
37
mp 59–618C (lit.[21] 63–648C). m/z (ESIþ) 288.1050;
C16H18NO2S (M þ H)þ requires 288.1053. nmax (neat)/cmꢀ1
2978, 2929, 1646, 1476, 1353, 1166. dH (CDCl3, 400 MHz) 1.43
(3H, d, J 6.5, CH3), 2.35 (3H, s, CH3), 2.45 (1H, dd, J 16.0, 2.9,
CHH), 2.89 (1H, dd, J 16.0, 9.4, CH), 4.35 (1H, m, NCH),7.00–
7.06 (2H, m, ArH), 7.16 (2H, d, J 8.0, ArH), 7.20–7.21 (1H, m,
ArH), 7.56 (2H, d, J 8.4, ArH), 7.65 (1H, d, J 8.0, ArH). dC
(CDCl3, 100 MHz) 21.5 (CH3), 23.4 (CH3), 36.2 (CH2), 58.5
(CH), 117.1 (CH), 124.4 (CH), 125.2 (CH), 127.0 (CH), 127.7
(CH), 129.5 (CH), 131.6 (C), 135.4 (C), 141.1 (C), 143.7 (C).
m/z (ESIþ), 592 (15 %), 305 (15), 288 ([M]þ, 100), 133 (6).
Chart 14.
Me
N
H
38
Chart 15.
2-Tosyl-1,2,3,4-tetrahydroisoquinoline 35
N-Benzylaniline 37
Triethylamine (1.07 mL, 7.67 mmol, 1.2 equiv.) was added to a
solution of 1,2,3,4-tetrahydroquinoline (0.85 g, 6.39 mmol,
1.0 equiv.) in dry THF (10 mL) A solution of p-toluenesulfonyl
chloride (1.46 g, 7.67 mmol, 1.2 equiv.) in THF (5 mL) was
slowly added at 08C. The reaction mixture was stirred for 18 h.
The mixture was poured into water (50 mL) and extracted with
ethyl acetate (3 ꢁ 15 mL). The combined organic layers were
washed with water (3 ꢁ 15 mL), brine (20 mL), dried over
Na2SO4, and concentrated under reduced pressure. The crude
mixture was purified by silica gel chromatography, eluting with
0–5 % ethyl acetate/light petroleum to afford 2-tosyl-1,2,3,4-
tetrahydroisoquinoline 35 (Chart 12) as a white solid (1.50 g,
82 %), mp 141–1438C (lit.[22] 141–1428C). m/z (ESIþ)
288.1050; C16H18NO2S (M þ H)þ requires 288.1053. nmax
(neat)/cmꢀ1 2929, 2862, 2824, 1591, 1342, 1163. dH (CDCl3,
400 MHz) 2.44 (3H, s, CH3), 2.95 (2H, t, J 5.9, CH2), 3.38 (2H, t,
J 5.9, CH2), 4.28 (2H, s, CH2), 7.04–7.10 (2H, m, ArH), 7.16
(2H, d, J 6.4, ArH), 7.33 (2H, d, J 8.0, ArH), 7.75 (2H, d, J 6.4,
ArH). dC (CDCl3, 100 MHz) 21.5 (CH3), 29.0 (CH2), 43.8
(CH2), 47.5 (CH2), 126.3 (CH), 126.8 (CH), 127.8 (CH), 128.8
(CH), 129.6 (CH), 131.7 (C), 133.0 (C), 133.1 (C), 143.6 (C).
m/z (ESIþ) 288 ([M]þ, 100 %), 310 (12), 279 (12), 186 (10).
The standard procedure for reduction was applied to N-benzyl-
4-methyl-N-phenylbenzenesulfonamide 33 (101 mg, 0.3 mmol,
1 equiv.). This was reacted with 1-methylisatin 11 (161 mg,
1 mmol, 3 equiv.). The crude product was purified by silica gel
chromatography, eluting with 0–20 % ethyl acetate/hexane to
afford N-benzylaniline 37 (Chart 14) as a white solid (46 mg,
84 %), mp 37–398C (lit. 34–368C).[24] m/z (ESI) 184.1119;
C11H14N (MH)þ requires 184.1121. nmax (neat)/cmꢀ1 3412,
3049, 3022, 1599, 1506, 689. dH (CDCl3) 4.08 (1H, br s, NH),
4.41 (2H, s, NCH2), 6.71–6.80 (2H, m, ArH), 6.81–6.83 (1H, m,
ArH), 7.25–7.29 (2H, m, ArH), 7.29–7.47 (5H, m, ArH). dC
(CDCl3, 100 MHz) 47.9 (CH2), 112.4 (CH), 117.1 (CH), 126.8
(CH), 127.1 (CH), 128.2 (CH), 128.8 (CH), 139.0 (C), 147.7 (C).
2-Methylindoline 38
The standard procedure for reduction was applied to 2-methyl-
1-tosylindoline 34 (86 mg, 0.3 mmol, 1 equiv.). This was reacted
with 1-methylisatin (161 mg, 1 mmol, 3 equiv.). The crude
product was purified by silica gel chromatography, eluting with
0–20 % ethyl acetate/hexane to afford 2-methylindoline 38
(Chart 15) as a colourless oil (31 mg, 79 %).[25] m/z (EIþ)
133.0884; C9H11N (M)þ requires 133.0891. nmax (neat)/cmꢀ1
3368, 3027, 2956, 1607, 1481, 1248, 743. dH (CDCl3, 400 MHz)
1.32, (3H, d, J 6.0, CH3) 2.68 (1H, dd, J 15.4, 7.6, ArCH2), 3.18
(1H, dd, J 15.4, 8.2, ArCH2), 3.37–3.41 (1H, br, NH), 4.00–4.07
(1H, m, CH), 6.63 (1H, d, J 7.6, ArH), 6.71 (1H, t, J 7.4, ArH),
7.02 (1H, t, J 7.6, ArH), 7.11 (1H, d, J 7.3, ArH). dC (CDCl3,
100 MHz) 21.8 (CH3), 37.3 (CH2), 54.7 (CH), 108.7 (CH), 118.1
(CH), 124.2 (CH), 126.7 (CH), 128.4 (C), 150.4 (C). m/z (ESIþ)
133 ([M]þ, 100 %), 94 (100), 78 (15).
Diphenylamine 36
The standard procedure for reduction was applied to 4-methyl-
N,N-diphenylbenzenesulfonamide 32 (97 mg, 0.3 mmol,
1 equiv.). This was reacted with 1-methylisatin (161 mg,
1 mmol, 3 equiv.). The crude product was purified by silica gel
chromatography, eluting with 0–20 % ethyl acetate/hexane to
afford diphenylamine 36 (Chart 13) as a white solid (39 mg,
76 %), mp 52–548C (lit.[23] 50–538C). m/z (ESIþ) 170.0966;
C12H11N (M þ H)þ requires 170.0964. nmax (neat)/cmꢀ1 3385,
3038, 1591, 1495, 1314, 746. dH (CDCl3, 400 MHz) 5.72 (1H, br
s, NH), 6.97 (2H, t, J 6.4, ArH), 7.11 (4H, d, J 6.6, ArH), 7.32
(4H, t, J 6.5, ArH). dC (CDCl3, 100 MHz) 117.4 (CH), 120.6
(CH), 128.9 (CH), 142.7 (C). m/z (ESIþ) 170 ([M þ H]þ,
100 %), 114 (12).
Attempted Reduction of 2-Tosyl-1,2,3,4-
tetrahydroisoquinoline 35
The standard procedure for reduction was applied to 2-tosyl-
1,2,3,4-tetrahydroisoquinoline 35 (86 mg, 0.3 mmol, 1 equiv.).
This was reacted with 1-methylisatin 11 (161 mg, 1 mmol,

Novel Organic Electron Donor Derived from N-Methylisatin
321
O
O
N
Me
N
H
S
O
42
Chart 19.
Me
35
Chart 16.
N-Methylcinnamamide 42
Similarly, N-methoxy-N-methylcinnamamide 40[27] (58 mg,
0.3 mmol, 1 equiv.) was reacted with 1-methylisatin (161 mg,
1 mmol, 3 equiv.). The crude product was purified by silica gel
chromatography, eluting with 0–30 % ethyl acetate/hexane to
afford N-methylcinnamamide 42 (Chart 19) as a colourless oil
(37 mg, 77 %). m/z (CIþ) 162.0912; C10H12NO (M þ H)þ
requires 162.0913. nmax (neat)/cmꢀ1 3368, 3027, 2956, 1607,
1481, 1248, 743. dH (CDCl3) 2.94 (3H, d, J 4.9, NCH3), 6.52
(1H, d, J 15.6, CH¼CH), 6.60 (1H, br s, NH), 7.31 (3H, dd, J 6.7,
2.9, ArH), 7.47 (2H, dd, J 6.7, 2.9, ArH), 7.63 (1H, d, J 15.6,
CH¼CH). dC (CDCl3) 26.0 (CH3), 120.3 (CH), 127.3 (CH),
128.3 (CH), 129.1 (CH), 134.3 (C), 140.1 (CH), 166.5 (C). m/z
(CIþ) 162 ([M]þ, 100 %), 323 (15), 235 (15).
O
Me
N
OMe
39
Chart 17.
O
Me
N
H
41
Cyclic Voltammogram of N-Methylisatin (Blue Trace in
Supplementary Material) with Standard Ferrocene
(Red Trace in Supplementary Material)
Chart 18.
Cyclic voltammetry was carried out in a glove box under
nitrogen using a glassy carbon working electrode, Ag/AgCl
reference electrode and platinum counter-electrode. The glassy
carbon working electrode, with a diameter of 7 mm (surface area
of 38.48 mm2), was cleaned before use using 1 micron alumina
polish and distilled water on a Bueller polishing cloth and dried
under compressed air. The counter-electrode consisted of a fine
Pt wire, which was cleaned thoroughly before use by heating in a
flame for 10 min and allowing to cool. Potentials are quoted with
respect to the Ag/AgCl/sat. KCl reference electrode, in contact
with 0.1 M tetrabutylammonium hexafluorophosphate in DMF.
Samples and standards were made up in an electrolyte solution
of 0.1 M tetrabutylammonium hexafluorophosphate in degassed
anhydrous DMF. A ferrocene external standard (1.861 g,
10 mmol in 100 mL) was made up in a 0.1 M solution of the
buffer and run before and after each measurement. The
N-methylisatin was made up in a 0.1 M solution of the buffer
(161.2 mg, 1 mmol in 10 mL).
1
3 equiv.). The H NMR of the crude reaction mixture showed
only unreacted sulfonamide 35 (Chart 16).
N-Methoxy-N-methylbenzamide 39
Under an inert atmosphere, triethylamine (3.51 mL, 25 mmol,
2.5 equiv.) was added dropwise to a suspension of benzoyl
chloride (1.4 mL, 10 mmol, 1.0 equiv.) and N,O-
dimethylhydroxylamine hydrochloride (1.17 g, 12 mmol,
1.2 equiv.) in dry DCM (25 mL) at 08C. The reaction mixture
was stirred for 1 h at 08C and for 16 h at room temperature. The
mixture was further diluted with DCM (50 mL) and washed with
1 M HCl (50 mL), NaHCO3 (3 ꢁ 50 mL), brine (50 mL), dried
over Na2SO4, and concentrated under reduced pressure to afford
N-methoxy-N-methylbenzamide 39 (Chart 17) as a yellow oil
(1.36 g, 83 %).[26] m/z (ESIþ) 166.0861; C9H12NO2 (M þ H)þ
requires 166.0863. nmax (neat)/cmꢀ1 3063, 2971, 2936, 1650,
1449, 1382, 710. dH (CDCl3, 500 MHz) 3.36 (3H, s, CH3), 3.56
(3H, s, CH3), 7.28–7.48 (3H, m, ArCH), 7.67 (2H, dd, J 8.0, 1.4,
ArH). dC (CDCl3, 125 MHz) 33.3 (CH3), 60.5 (CH3), 127.5
(CH), 127.6 (CH), 130.1 (CH), 133.6 (C), 169.4 (C). m/z (ESIþ)
331 (10 %), 188 (6), 166 ([M þ H]þ, 100).
Supplementary Material
The Supplementary Material contains cyclic voltammogram
of N-methylisatin and 1H NMR and 13C-NMR spectra of
compounds and can be found on the Journal’s website.
N-Methylbenzamide 41
Acknowledgements
The standard procedure for reduction was applied to
N-methoxy-N-methylbenzamide 39 (49 mg, 0.3 mmol,
1 equiv.). This was reacted with 1-methylisatin (161 mg,
1 mmol, 3 equiv.). The crude product was purified by silica gel
chromatography, eluting with 0–30 % ethyl acetate/hexane to
afford N-methylbenzamide 41 (Chart 18) as a colourless oil
(32 mg, 79 %). nmax (neat)/cmꢀ1 3325, 3057, 2969, 1650, 1550,
1310. dH (CDCl3) 2.99 (3H, d, J 4.8, NCH3), 6.6 (1H, br s, NH),
7.40 (2H, t, J 7.1, ArH), 7.49 (1H, t, J 7.1, ArH), 7.78 (2H, d, J
7.1, ArH). dC (CDCl3) 26.3 (CH3), 126.4 (CH), 128.0 (CH),
130.8 (CH), 134.1 (C), 169.4 (C).
We thank the EPSRC for fundingand the EPSRC Mass spectrometry Service
Centre for mass spectra.
References
[1] (a) D. Parmar, H. Matsubara, K. Price, M. Spain, D. J. Procter, J. Am.
Chem. Soc. 2012, 134, 12751. doi:10.1021/JA3047975
(b) D. Parmar, L. A. Duffy, D. V. Sadasivam, H. Matsubara,
P. A. Bradley, R. A. Flowers, II, D. J. Procter, J. Am. Chem. Soc.
2009, 131, 15467. doi:10.1021/JA906396U
(c) A. Gansa¨uer, M. Klatte, G. M. Bra¨ndle, J. Friedrich, Angew. Chem.
Int. Ed. 2012, 51, 8891. doi:10.1002/ANIE.201202818

322
R. Sword, S. O’Sullivan, and J. A. Murphy
[2] (a) D. A. Nicewicz, D. W. C. MacMillan, Science 2008, 322, 77.
(h) P. I. Jolly, S. Zhou, D. W. Thomson, J. Garnier, J. A. Parkinson,
T. Tuttle, J. A. Murphy, Chem. Sci. 2012, 3, 1675. doi:10.1039/
C2SC20054F
(i) P. I. Jolly, N. Fleary-Roberts, S. O’Sullivan, E. Doni, S. Zhou,
J. A. Murphy, Org. Biomol. Chem. 2012, 10, 5807. doi:10.1039/
C2OB25116G
doi:10.1126/SCIENCE.1161976
(b) M. A. Ischay, M. E. Anzovino, J. Du, T. P. Yoon, J. Am. Chem. Soc.
2008, 130, 12886. doi:10.1021/JA805387F
(c) D. A. Nagib, M. E. Scott, D. W. C. MacMillan, J. Am. Chem. Soc.
2009, 131, 10875. doi:10.1021/JA9053338
(d) H.-W. Shih, M. N. V. Wal, R. L. Grange, D. W. C. MacMillan,
J. Am. Chem. Soc. 2010, 132, 13600. doi:10.1021/JA106593M
(e) J. M. R. Narayanam, C. R. J. Stephenson, Chem. Soc. Rev. 2011, 40,
102. doi:10.1039/B913880N
(j) J. Garnier, D. W. Thomson, S. Zhou, P. I. Jolly, L. E. A. Berlouis,
J. A. Murphy, Beilstein J. Org. Chem. 2012, 8, 994. doi:10.3762/
BJOC.8.112
[10] Re compound 6: W. W. Porter III, T. P. Vaid, A. L. Rheingold, J. Am.
Chem. Soc. 2005, 127, 16559. doi:10.1021/JA053084Q
[11] Re compound 7: T. P. Vaid, J. Am. Chem. Soc. 2011, 133, 15838.
doi:10.1021/JA205738Z
(f) J. D. Nguyen, E. M. D’Amato, J. M. R. Narayanam, C. R. J.
Stephenson, Nat. Chem. 2012, 4, 854. doi:10.1038/NCHEM.1452
[3] S. Zhou, H. Farwaha, J. A. Murphy, Chimia 2012, 66, 418.
doi:10.2533/CHIMIA.2012.418
[12] Re compound 8: Z. Han, T. P. Vaid, A. L. Rheingold, J. Org. Chem.
[4] (a) E. Cahard, F. Schoenebeck, J. Garnier, S. P. Y. Cutulic, S. Zhou,
J. A. Murphy, Angew. Chem. Int. Ed. 2012, 51, 3673. doi:10.1002/
ANIE.201200084
2008, 73, 445. doi:10.1021/JO701944C
[13] (a) A. Peters, E. Kaifer, H.-J. Himmel, Eur. J. Org. Chem. 2008, 5907.
doi:10.1002/EJOC.200800900
(b) D. P. Hari, P. Schroll, B. Ko¨nig, J. Am. Chem. Soc. 2012, 134, 2958.
doi:10.1021/JA212099R
[5] (a) C. Lampard, J. A. Murphy, N. Lewis, J. Chem. Soc. Chem.
(b) V. Vitske, C. Ko¨nig, O. Hu¨bner, E. Kaifer, H.-J. Himmel, Eur. J.
Inorg. Chem. 2010, 115. doi:10.1002/EJIC.200900724
[14] A. R. Katritzky, W.-Q. Fan, D.-S. Liang, Q.-L. Li, J. Heterocycl.
Chem. 1989, 26, 1541. doi:10.1002/JHET.5570260607
[15] (a) A. L. J. Beckwith, W. B. Gara, J. Am. Chem. Soc. 1969, 91, 5689.
doi:10.1021/JA01048A074
Commun. 1993, 295. doi:10.1039/C39930000295
(b) R. J. Fletcher, C. Lampard, J. A. Murphy, N. Lewis, J. Chem. Soc.,
Perkin Trans. 1 1995, 623. doi:10.1039/P19950000623
[6] Re compound 2: M. Me´debielle, W. A. Dolbier, Jr, J. Fluor. Chem.
2008, 129, 930. doi:10.1016/J.JFLUCHEM.2008.06.029
[7] Re compound 3: (a) J. R. Ames, M. A. Houghtaling, D. L. Terrian,
T. P. Mitchell, Can. J. Chem. 1997, 75, 28. doi:10.1139/V97-004
(b) J. Bourson, Bull. Soc. Chim. Fr. 1971, 3541.
(b) A. L. J. Beckwith, W. B. Gara, J. Chem. Soc., Perkin Trans. 2 1975,
593. doi:10.1039/P29750000593
(c) A. N. Abeywickrema, A. L. J. Beckwith, Chem. Commun. 1986,
464. doi:10.1039/C39860000464
(d) A. L. J. Beckwith, W. B. Gara, J. Org. Chem. 1987, 52, 4072.
doi:10.1021/JO00386A007
(c) S. Hu¨nig, D. Scheutzow, H. Schlaf, H. Quast, Liebigs Ann. Chem.
1972, 765, 110.
(d) R. P. Thummel, V. Goulle, B. Chen, J. Org. Chem. 1989, 54, 3057.
doi:10.1021/JO00274A019
[16] D. P. Curran, M. J. Totleben, J. Am. Chem. Soc. 1992, 114, 6050.
doi:10.1021/JA00041A024
[17] (a) K. R. Wursthorn, H. G. Kuivila, G. F. Smith, J. Am. Chem. Soc.
(e) Z. Shi, R. P. Thummel, J. Org. Chem. 1995, 60, 5935. doi:10.1021/
JO00123A034
(f) J. A. Murphy, T. A. Khan, S.-Z. Zhou, D. W. Thomson, M. Mahesh,
Angew. Chem. Int. Ed. 2005, 44, 1356. doi:10.1002/ANIE.200462038
[8] Re compound 4: (a) T. A. Taton, P. Chen, Angew. Chem. Int. Ed. Engl.
1996, 35, 1011. doi:10.1002/ANIE.199610111
1978, 100, 2779. doi:10.1021/JA00477A034
(b) M. Mori, N. Isono, N. Kaneta, M. Shibasaki, J. Org. Chem. 1993,
58, 2972. doi:10.1021/JO00063A012
(c) M. Mori, N. Kaneta, N. Isono, M. Shibasaki, J. Organomet. Chem.
1993, 455, 255. doi:10.1016/0022-328X(93)80407-3
(d) M. Mori, N. Kaneta, M. Shibasaki, J. Organomet. Chem. 1994, 464,
35. doi:10.1016/0022-328X(94)87005-5
(b) J. A. Murphy, S.-Z. Zhou, D. W. Thomson, F. Schoenebeck,
M. Mahesh, S. R. Park, T. Tuttle, L. E. A. Berlouis, Angew. Chem.
Int. Ed. 2007, 46, 5178. doi:10.1002/ANIE.200700554
(c) F. Schoenebeck, J. A. Murphy, S. Z. Zhou, Y. Uenoyama, Y. Miclo,
T. Tuttle, J. Am. Chem. Soc. 2007, 129, 13368. doi:10.1021/
JA074417H
[18] L. Pause, L. M. Robert, J.-M. Save´ant, J. Am. Chem. Soc. 1999, 121,
7158. doi:10.1021/JA991365Q
[19] C. P. Andrieux, J. Pinson, J. Am. Chem. Soc. 2003, 125, 14801.
doi:10.1021/JA0374574
[20] Z. Liu, R. C. Larock, J. Org. Chem. 2006, 71, 3198. doi:10.1021/
JO0602221
[21] Y. Yin, G. Zhao, J. Fluor. Chem. 2007, 128, 40. doi:10.1016/
J.JFLUCHEM.2006.09.012
[9] Re compound 5: (a) J. A. Murphy, J. Garnier, S. R. Park,
F. Schoenebeck, S.-Z. Zhou, A. T. Turner, Org. Lett. 2008, 10,
1227. doi:10.1021/OL800134G
(b) J. Garnier, J. A. Murphy, S.-Z. Zhou, A. T. Turner, Synlett 2008,
2127. doi:10.1055/S-2008-1078242
(c) S. P. Y. Cutulic, J. A. Murphy, H. Farwaha, S.-Z. Zhou, E. Chrystal,
Synlett 2008, 2132. doi:10.1055/S-2008-1078240
[22] F. G. Holliman, F. G. Mann, J. Chem. Soc. 1942, 737. doi:10.1039/
JR9420000737
[23] Aldrich Handbook of Chemicals 2005 (Sigma–Aldrich Co. Ltd:
Gillingham, UK).
(d) S. P. Y. Cutulic, N. J. Findlay, S. Z. Zhou, E. J. T. Chrystal,
J. A. Murphy, J. Org. Chem. 2009, 74, 8713. doi:10.1021/JO901815T
(e) J. A. Murphy, F. Schoenebeck, N. J. Findlay, D. W. Thomson,
S.-Z. Zhou, J. Garnier, J. Am. Chem. Soc. 2009, 131, 6475.
doi:10.1021/JA8092746
[24] A. R. Katritzky, G. Yao, X. Lan, X. Zhao, J. Org. Chem. 1993, 58,
2086. doi:10.1021/JO00060A025
[25] Q. A. Kulkarni, W. Zhou, B. To¨ro¨k, Org. Lett. 2011, 13, 5124.
doi:10.1021/OL2019899
[26] W. J. Kerr, A. J. Morrison, M. Pazicky, T. Weber, Org. Lett. 2012, 14,
(f) J. Garnier, A. R. Kennedy, L. E. A. Berlouis, A. T. Turner,
J. A. Murphy, Beilstein J. Org. Chem. 2010, 6, No. 73. doi:10.3762/
BJOC.6.73
(g) R. Sword, L. A. Baldwin, J. A. Murphy, Org. Biomol. Chem. 2011,
9, 3560. doi:10.1039/C0OB01282C
2250. doi:10.1021/OL300652K
[27] J. A. Murphy, A. G. J. Commeureuc, T. N. Snaddon, T. M. McGuire,
T. A. Khan, K. Hisler, M. L. Dewis, R. Carling, Org. Lett. 2005, 7,
1427. doi:10.1021/OL050337B