Indium(I) bromide-promoted stereoselective preparation of cyclopropanes via sequential aldol-type coupling/elimination/Michael-induced ring closure reaction from α,α-dichloroacetophenone and aldehydes

Article abstract of DOI:10.1016/j.jorganchem.2008.08.011

The indium enolate generated from indium(I) bromide and α,α-dichloroacetophenone reacts with aldehydes to produce (syn + anti)-2-chloro-3-hydroxy-propan-1-ones which can be converted to their trans-prop-2-en-1-ones derivatives upon reaction with an extra equivalent of InBr. The enones undergo Michael-induced ring closure reactions with an extra equivalent of the initial enolate to afford the corresponding cyclopropane derivatives, according to a sequenced reaction mechanism.

Full text of DOI:10.1016/j.jorganchem.2008.08.011

Journal of Organometallic Chemistry 693 (2008) 3441–3445
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Indium(I) bromide-promoted stereoselective preparation of cyclopropanes via
sequential aldol-type coupling/elimination/Michael-induced ring closure
reaction from a,a-dichloroacetophenone and aldehydes
*
Clovis Peppe , Rafael Pavão das Chagas, Robert Alan Burrow
Laboratório de Materiais Inorgânicos, Departamento de Química, Universidade Federal de Santa Maria, Santa Maria-RS 97105-900, Brazil
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 10 June 2008
Received in revised form 6 August 2008
Accepted 7 August 2008
Available online 12 August 2008
The indium enolate generated from indium(I) bromide and a,a-dichloroacetophenone reacts with alde-
hydes to produce (syn + anti)-2-chloro-3-hydroxy-propan-1-ones which can be converted to their trans-
prop-2-en-1-ones derivatives upon reaction with an extra equivalent of InBr. The enones undergo
Michael-induced ring closure reactions with an extra equivalent of the initial enolate to afford the corre-
sponding cyclopropane derivatives, according to a sequenced reaction mechanism.
Ó 2008 Elsevier B.V. All rights reserved.
Keywords:
Indium(I)
Aldol-type coupling
Elimination reaction
Michael-induced ring closure reaction
Sequential chemical reactions
1. Introduction
stances [7]. The cyclopropanation of electron-deficient olefins by
pyridinium, sulfonium, selenonium, and phosphonium ylides was
Recent work from this laboratory demonstrated that the orga-
noindium(III) compounds, 1 derived of the oxidative insertion of
indium(I) bromide [1] into one of the carbon-halogen bonds of
geminal dihalides, RR1CX2 (1a, R = C6H5CO, R1 = H, X = Cl [2]; 1b,
R = CN, R1 = H, X = Br [3]; 1c, R = CN, R1 = X = Cl [4]) couple with
carbonyl compounds, particularly aldehydes, R2CHO (R2 = alkyl,
aryl) to afford initially the corresponding indium(III) alkoxides, 2
which undergo elimination to alkenes, 3 in a sequential fashion
upon reaction with an extra equivalent of indium(I) bromide
(Scheme 1) [5].
rather well studied [8]. Michael-initiated ring closure (MIRC), reac-
tion involving ylides and electron-deficient olefins, is one of the
most important methods for the preparation of cyclopropanes.
The stereoselectivity of the MIRC reactions depends on how fast
is the ring closure process related to rotation around the single
bond in the intermediate, and therefore mixtures of stereoisomers
are expected [9]. The finding of new reagents capable of forming
the three-membered ring, particularly those leading to a high de-
gree of stereoselectivity under mild reaction conditions is highly
desirable [7a,9].
The organoindium(III) compounds 1 contain a nucleophilic alkyl
We now show that the organoindium compound obtained
substituent bearing
a
leaving group and therefore they are
from InBr and
a,a-dichloroacetophenone, Br(Cl)InCHClCOPh, 1a
expected to give rise to Michael-induced ring closure (MIRC) reac-
tions with an electrophilic alkene, 4 to produce the corresponding
cyclopropane, 5 (Scheme 2).
is able to react with selected electron deficient alkenes to
produce the corresponding cyclopropyl-phenyl-methanone,
(Table 1).
6
Cyclopropanes have always attracted the attention of chemists
because of the bonding aspects associated with their strained ring
and/or their versatility as synthetic intermediates in organic syn-
thesis [6]. Cyclopropanes are found as a basic structural unit in a
variety of naturally occurring compounds and they have been used
as building blocks for the synthesis of natural and artificial sub-
2. Results and discussion
The alkene to cyclopropane transformations were realized
independently by two different methods. The first (method A)
involves the direct reaction of the electron deficient alkene
and 1a. Optimum reaction conditions were determined from
experiments with (E)-3-(4-chlorophenyl)-1-phenyl-2-propen-1-
one (entry b), which produced a 4:1 mixture of the cyclopropanes
c-1,t-2-dibenzoyl-r-3-(40-chlorophenyl)cyclopropane (6b) and
* Corresponding author. Tel.: +55 55 3220 8868; fax: +55 55 3220 8031.
E-mail address: peppe@quimica.ufsm.br (C. Peppe).
0022-328X/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2008.08.011

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C. Peppe et al. / Journal of Organometallic Chemistry 693 (2008) 3441–3445
R
R1
X
R2
R
R2
+ InX
R2CHO
InX
RR1CX2
X2InCRR1X
- (X2In)2O
1
2
R1
3
OInX2
Scheme 1. Indium(I) halide-promoted sequential intermolecular aldol-type coupling/elimination reactions from RR0CX2 compounds and aldehydes.
R1
R1
LG
CRR1-LG
EWG
EWG
EWG
R
R
4
5
Scheme 2. Michael-induced ring closure (MIRC) reactions.
Table 1
Indium(I) bromide-promoted sequential intermolecular aldol-type coupling/elimination/MIRC reactions of
a
,a
-dichloroacetophenone and aldehydes
O
R1
R1
R2
PhOC
PhOC
InBr
H
H
+
+
THF , Δ
R2
R1
H
H
Cl2HC
Ph
20 h
R
R2
R
R
6'
6
R
R1
R2
6 + 60 (%)a
6:60
a
b
c
d
e
f
g
h
i
C6H5
PhCO
PhCO
PhCO
PhCO
PhCO
PhCO
PhCO
CN
H
H
H
H
H
H
H
CN
CN
CN
H
71 (37)
3:1(5:2)
4:1(4:1)
ꢀ(2:1)
ꢀ(>98:1)c
5:2(2:1)
>98:1c
>98:1c
>98:1c
>98:1c
>98:1c
–
p-Cl-C6H4
p-Br-C6H4
o-Br-C6H4
p-CH3-C6H4
p-CH3O-C6H4
n-C3H7
75 (55) [53]b
ꢀ(40)
ꢀ(30)
48 (27)
40
62
61
77
33
0
C6H5
p-Cl-C6H4
p-CH3O-C6H4
p-Cl-C6H4
CN
CN
CN
j
k
Optimal reaction conditions (stoichiometric ratio, temperature and time) were determined from experiments involving (E)-3-(4-chlorophenyl)-1-phenyl-2-propen-1-one
(entry b): alkene:PhCOCHCl2:InBr = 2:1:2 (Method A)
a
Yields in parenthesis correspond to experiments starting from the aldehyde RCHO, PhCOCHCl2 and InBr in the molar ratio 2:1:3 (Method B).
b
Yields in brackets corresponds to experiment starting from the alkene, PhCOCHCl2 and InBr in the molar ratio 1:1:1.
c
Evaluated by 1H NMR spectroscopy, the minor isomer was not isolated.
t-1,t-2-dibenzoyl-r-3-(40-chlorophenyl)cyclopropane (60b) in 75%
of yield, when the reaction is carried out in the stoichiometric ratio
alkene:PhCOCHCl2:InBr of 1:1:2. A substantial decrease in the yield
to 55% was observed decreasing the amount of InBr to a 1:1:1 ratio.
Poorer and similar yield was again observed using method B, when
has been proposed for cyclopropanations with tellurium ylides
[9a]; steric hindrance between the aromatic R group of the al-
kene and the benzoyl group of the nucleophile determines the
trans relationship.
The trans stereochemistry relating the incoming benzoyl and
the alkene R group in the cyclopropane ring so being determined,
we now address the stereochemistry of the alkene R1 and R2
groups present in the enone series (entries a–g; R1 = PhCO,
R2 = H). In these reactions, we clearly lose the initial trans-stereo-
chemistry of the enone leading to a mixture of cyclopropanes 6
and 60. Loss of stereochemistry relating the R and R1 groups in
enones during MIRC-type cyclopropanations has been interpreted
in terms of rotation around the single bond in the intermediate
(see Fig. 2). Such a phenomenon seems to be operative in these
reactions promoted by the indium enolate. Fig. 2 indicates which
transition state is favoured in terms of the minimum interaction
between the bulky groups of the two possibilities generated by
the single bond rotation. The preferential formation of cyclopro-
panes, 6 as indeed is observed clearly requires the minimum
energy.
the enone was generated from p-chlorobenzaldehyde, a,a-dichlo-
roacetophenone and InBr in the molar ratio 2:1:3.
Alkenes reactivity follows closely the expected pattern for
MIRC reactions. Accordingly, the more electron withdrawing abil-
ity of the alkene R group, the higher is the reaction yield as it
was in fact observed for both the enone (entries a–g) and 1,1-
dicyanoethylene (entries h–j) series. The stereochemistry of the
three-membered rings was readily determined by 1H NMR
spectroscopy (see Section 4) and in two cases – namely c-1,t-2-
dibenzoyl-r-3-(40-chlorophenyl)cyclopropane (6b) and trans-2-
benzoyl-3-(40-chlorophenyl)-1,1-dicyanocyclopropane (6i) – was
confirmed by X-ray single crystal analysis. Cyclopropanation of
2-aryl-1,1-dicyanoethylenes (entries h–j) leads to trans-products
with a high degree of stereoselectivity (trans:cis > 98:1) as im-
posed by the transition state model depicted at Fig. 1 which

C. Peppe et al. / Journal of Organometallic Chemistry 693 (2008) 3441–3445
3443
of up to three new carbon-carbon bonds. The complete sequence
is illustrated at Scheme 3 which shows the following properties
of the enolate: it couples with a second molecule of the dichlorok-
etone to produce, after reduction with excess of indium monobro-
mide, the corresponding 1,4-butanediones, 7 [2a]; alternatively,
the enolate condenses with an aldehyde to give the corresponding
2-chloro-3-hydroxy-propan-1-one derivative, 8 which can be eas-
ily converted into the trans-epoxide, 9 by treatment with a conve-
nient base [2b] or transformed into the respective chalcone, 10 by
elimination with an extra equivalent of InBr [5a]. The final step of
the sequenced process is the formation of the cyclopropane rings
by the action of enolate 1a in the chalcone following a MIRC reac-
tion pathway.
O
OInX2
Cl
Cl
Ph
Ph
+
InX2
CN
Ar
CN
Throughout the sequence, mechanistic descriptions and transi-
tion state models that satisfactorily explain reaction details, partic-
ularly stereochemical features, have been proposed. We expect,
therefore, that this knowledge will shed some light to organic
chemists planning to use indium monohalides as promoters of
organic reactions.
Cl
Cl
H
Ar
H
Ar
PhOC
NC
H
H
PhOC
NC
favoured
CN
CN
4. Experimental
4.1. General data
PhOC
CN
PhOC
CN
CN
H
Ar
H
Indium monobromide, a,a-dichloroacetophenone, aldehydes
and solvents were prepared or treated as described in previous
work [2,5a]. All the chalcones (Table 1, entries a–f) were prepared
by the Claisen–Schmidt reaction: An ethanol solution (20 mL) of
acetophenone (20 mmol) was added to a 10% KOH solution
(60 mL); the resulting solution was cooled to 0 °C and the aromatic
aldehyde (20 mmol) dissolved in EtOH (5 mL) was added; the
resulting mixture was stirred at room temperature (25 °C) for
4 h; the precipitated chalcone was filtered, washed with H2O and
ethanol and recrystallized from hot ethanol; this procedure affords
the chalcones in yields varying from 60% to 80%. (E)-1-phenyl-2-
hexen-1-one (entry g) [5a], the 1,1-dicyano alkenes (entries h–j)
[10a,b] and the alkenenitrile (entry k) [10c] were prepared accord-
ing to literature methods. 1H and 13C NMR spectra were acquired
on spectrometers Bruker DPX 200 and 400. Mass spectra were reg-
istered in a HP 6890 GC (equipped with a split–splitless injector
and a cross-linked HP-5 capillary column measuring 30 m and with
internal diameter of 0.32 mm) connected to a HP 5973 MSD spec-
trometer, with helium as the carrier gas.
H
H
CN
Ar
6 (h-j)
6' (h-j)
Fig. 1. Transition state models for cyclopropanation of 2-aryl-1,1-dicyanoethylenes.
Cl
Cl
H
R
H
H
R
H
PhOC
PhOC
R2
R1
R1
R2
favoured (R1= COPh, R2= H)
R2
R1
R2
PhOC
4.2. Indium(I) bromide-promoted stereoselective preparation of
cyclopropanes via sequential aldol-type coupling/elimination/Michael-
PhOC
H
H
R
induced ring closure reactions from
aldehydes
a,a-dichloroacetophenone and
R1
H
H
R
Method A: A Schlenk test tube equipped with a condenser, truly
dried under high vacuum, was charged with 3 mL of dry (sodium)
THF, 150 mg (0.75 mmol) of the red solid InBr, 95 mg (0.50 mmol,
6
6'
Fig. 2. Transition state models for cyclopropanation of enones.
71 lL) of a,a-dichloroacetophenone and 0.75 mmol of the corre-
sponding alkene (entries a–k – Table 1). The reaction was kept un-
der reflux for 20 h (monitored by TLC), under a dry nitrogen
atmosphere. At the end of this period, the reaction was quenched
with water. The organics were extracted with dichloromethane.
The extract was dried (Na2SO4) and evaporated to dryness. The
cyclopropanes 6 and 60 were separated by column chromatography
with hexanes–ethyl acetate mixtures.
3. Conclusion
The indium enolate obtained from the oxidative insertion of
InBr into one of the carbon-chlorine bonds of -dichloroaceto-
phenone effectively promotes the cyclopropanation of alkenes
bearing electron withdrawing groups, such as enones and 1,1-dicy-
ano-2-aryl-ethenes. The reactions follow closely the MIRC pro-
a,a
Method B: In the same apparatus, 3 mL of dry (sodium) THF,
293 mg (1.50 mmol) of the red solid InBr, 189 mg (1.00 mmol,
posed mechanisms and transition state models allowing
a
142 lL) of a,a-dichloroacetophenone and 0.50 mmol of the corre-
sponding aldehyde were heated under reflux in a dry N2 atmo-
sphere for 20 h. Similar work up produced cyclopropanes 6 and
complete understanding of their effectiveness and stereoselectivity
were proposed. Moreover, this is the final step of a series of reac-
tions which can be carried out sequentially leading to formation

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C. Peppe et al. / Journal of Organometallic Chemistry 693 (2008) 3441–3445
1a
InBr
RCHO
ArCOCHCl2
+ 3 InBr
O
O
R
6 + 6'
Ph
R
1a
Ph
OInX2
trans (only)
10
H+
Ph
Cl
O
O
R
Ar
Ph
OH
7
O
8
Cl
O
Et3N
R
R1OC
9
trans (only)
Scheme 3. Indium(I) bromide-promoted sequential intermolecular aldol-type coupling/elimination reactions from
a,a-dichloroacetophenone and aldehydes.
60. Yields of reactions are given in Table 1, analytical and spectro-
scopic data for products 6 and 60 are as follows:
t-1,t-2-Dibenzoyl-r-3-(40-bromophenyl)cyclopropane (60c): Color-
less solid; m.p. 170–172 °C. 1H NMR (CDCl3): d = 3.28 (d,
J = 6.3 Hz, 2H), 3.44 (t, J = 6.3 Hz, 1H), 7.07–7.15 (m, 2H), 7.31–
7.51 (m, 8H), 7.88–7.92 (m, 4H). 13C NMR (CDCl3): d = 30.41,
36.76, 121.00, 128.24, 128.30, 128.60, 131.93, 133.25, 136.99,
137.56, 193.89. MS (EI, 70 eV, for 79Br): m/z (%) = 299 (47), 220
(25), 192 (16), 115 (15), 105 (100), 77 (63).
c-1,t-2-Dibenzoyl-r-3-phenylcyclopropane (6a) [11]: Colorless
solid; m.p. 115–117 °C (lit. 113–114 °C). 1H NMR (CDCl3):
d = 3.47 (dd, J = 6.0, 10 Hz, 1H), 3.69 (dd, J = 5.0, 10 Hz, 1H), 4.17
(dd, J = 5.0, 6.0 Hz, 1H), 7.00–7.22 (m, 5H), 7.25–7.58 (m, 6H),
7.84–7.94 (m, 2H), 8.01–8.12 (m, 2H). 13C NMR (CDCl3):
d = 29.75, 37.40, 37.99, 127.23, 128.22, 128.27, 128.40, 128.57,
128.68, 128.73, 133.18, 133.50, 134.27, 137.02, 137.44, 193.64,
197.32. MS (EI, 70 eV): m/z (%) = 326 [M]+ (1), 221 (100), 203
(11), 143 (5), 115 (35), 105 (100), 77 (100).
c-1,t-2-Dibenzoyl-r-3-(20-bromophenyl)cyclopropane (6d): Color-
less solid; m.p. 144–146 °C. 1H NMR (CDCl3): d = 3.53 (dd, J = 6.4,
9.5 Hz, 1H), 3.87 (dd, J = 4.6, 9.5 Hz, 1H), 4.14 (dd, J = 4.6, 6.4 Hz,
1H), 6.96–7.06 (m, 1H), 7.15–7.60 (m, 9H), 7.96–8.10 (m, 4H). 13C
NMR (CDCl3): d = 31.43, 36.45, 38.95, 126.03, 129.98, 128.47,
128.49, 128.63, 128.80, 128.85, 130.64, 132.59, 133.24, 133.63,
133.92, 136.93, 137.24, 193.81, 196.80. MS (EI, 70 eV, for 79Br):
m/z (%) = 325 (15), 299 (29), 220 (13), 192 (13), 115 (12), 105
(100), 77 (58). Anal. Calc. for C23H17BrO2: C, 68.16; H, 4.23. Found:
C, 68.50; H, 4.27%.
t-1,t-2-Dibenzoyl-r-3-phenylcyclopropane (60a) [11]: Colorless
solid; m.p. 148–150 °C (lit. 150–151 °C). 1H NMR (CDCl3):
d = 3.31 (d, J = 6.0 Hz, 2H), 3.47 (t, J = 6.0 Hz, 1H), 7.17–7.49 (m,
11H), 7.88–7.97 (m, 4H). 13C NMR (CDCl3): d = 31.25, 36.86,
126.59, 128.33, 128.53, 128.85, 127.21, 133.02, 137.40, 138.59,
194.17. MS (EI, 70 eV): m/z (%) = 221 (100), 203 (6), 115 (22), 105
(94), 77 (63).
c-1,t-2-Dibenzoyl-r-3-(40-methylphenyl)cyclopropane (6e): Color-
less solid; m.p. 135–136 °C. 1H NMR (CDCl3): d = 2.15 (s, 3H), 3.44
(dd, J = 6.0, 9.9 Hz, 1H), 3.68 (dd, J = 4.9, 9.9 Hz, 1H), 4.15 (dd,
J = 4.9, 6.0 Hz, 1H), 6.93 (d, J = 8.0 Hz, 2H), 7.06 (d, J = 8.0 Hz, 2H),
7.27–7.56 (m, 6H), 7.84–7.94 (m, 2H), 8.01–8.11 (m, 2H). 13C
NMR (CDCl3): d = 21.01, 29.89, 37.44, 37.91, 128.29, 128.40,
128.55, 128.57, 128.73, 128.96, 131.21, 133.14, 133.46, 136.86,
137.08, 137.54, 193.79, 197.43. MS (EI, 70 eV): m/z (%) = 340 [M]+
(1), 235 (100), 129 (6), 115 (12), 105 (92), 77 (49). Anal. Calc. for
c-1,t-2-Dibenzoyl-r-3-(40-chlorophenyl)cyclopropane (6b): Color-
less solid; m.p. 140–141 °C. 1H NMR (CDCl3): d = 3.43 (dd, J = 6.0,
9.9 Hz, 1H), 3.69 (dd, J = 5.0, 9.9 Hz, 1H), 4.13 (dd, J = 5.0, 6.0 Hz,
1H), 7.10 (s, broad, 4H), 7.27–7.60 (m, 6H), 7.80–7.96 (m, 2H),
8.00–8.11 (m, 2H). 13C NMR (CDCl3): d = 29.85, 36.97, 37.26,
128.26, 128.40, 128.42, 128.67, 128.79, 130.05, 132.85, 133.11,
133.37, 133.62, 136.91, 137.32, 193.46, 196.95. MS (EI, 70 eV, for
35Cl): m/z (%) = 255 (67), 220 (9), 192 (6), 115(10), 105 (100), 77
(72). Anal. Calc. for C23H17ClO2: C, 76.56; H, 4.75. Found: C,
76.31; H, 4.52%.
C
24H20O2: C, 84.68; H, 5.92. Found: C, 84.91; H, 5.33%.
t-1,t-2-Dibenzoyl-r-3-(40-methylphenyl)cyclopropane (60e): Color-
t-1,t-2-Dibenzoyl-r-3-(40-chlorophenyl)cyclopropane (60b): Color-
less solid; m.p. 158–160 °C. 1H NMR (CDCl3): d = 3.29 (d,
J = 6.2 Hz, 2H), 3.44 (t, J = 6.2 Hz, 1H), 7.13–7.52 (m, 10H), 7.83–
7.95 (m, 4H). 13C NMR (CDCl3): d = 30.33, 36.79, 127.87, 128.28,
128.58, 128.94, 132.95, 133.23, 136.95, 136.98, 193.91. MS (EI,
70 eV, for 35Cl): m/z (%) = 255 (86), 220 (23), 192 (8), 115 (11),
105 (100), 77 (67). Anal. Calc. for C23H17ClO2: C, 76.56; H, 4.75.
Found: C, 76.74; H, 4.62%.
less solid; m.p. 153–155 °C. 1H NMR (CDCl3): d = 2.29 (s, 3H), 3.28
(d, J = 6.0 Hz, 2H), 3.43 (t, J = 6.0 Hz, 1H), 7.05–7.15 (m, 4H), 7.30–
7.37 (m, 4H), 7.42–7.48 (m, 2H), 7.88–7.94 (m, 4H). 13C NMR
(CDCl3): d = 21.06, 31.10, 36.85, 126.41, 128.32, 128.53, 129.50,
133.07, 135.40, 136.94, 137.21, 194.43. MS (EI, 70 eV): m/z
(%) = 340 [M]+ (1), 235 (100), 129 (8), 115(14), 105 (85), 77 (52).
c-1,t-2-Dibenzoyl-r-3-(40-methoxyphenyl)cyclopropane (6f): Col-
orless solid; m.p. 93–96 °C. 1H NMR (CDCl3): d = 3.42 (dd, J = 6.1,
9.8 Hz, 1H), 3.62 (s, 3H), 3.67 (dd, J = 5.0, 9.8 Hz, 1H), 4.12 (dd,
J = 5.0, 6.1 Hz, 1H), 6.62–6.68 (m, 2H), 7.02–7.11 (m, 2H), 7.30–
7.55 (m, 6H), 7.84–7.93 (m, 2H), 8.00–8.08 (m, 2H). 13C NMR
(CDCl3): d = 29.97, 37.46, 37.58, 55.05, 113.64, 126.20, 128.24,
128.36, 128.55, 128.69, 129.71, 133.12, 133.43, 137.05, 137.50,
158.64, 193.78, 197.37. MS (EI, 70 eV): m/z (%) = 356 [M]+ (1),
251 (100), 115 (8), 105 (77), 77 (43). Anal. Calc. for C24H20O3: C,
80.88; H, 5.66. Found: C, 81.31; H, 5.02%.
c-1,t-2-Dibenzoyl-r-3-(40-bromophenyl)cyclopropane (6c) [12]:
Colorless solid; m.p. 161–163 °C (lit. 165 °C). 1H NMR (CDCl3):
d = 3.42 (dd, J = 6.0, 10.0 Hz, 1H), 3.69 (dd, J = 5.0, 10.0 Hz, 1H),
4.13 (dd, J = 5.0, 6.0 Hz, 1H), 7.05 (d, J = 8.2 Hz, 2H), 7.24–7.60 (m,
8H), 7.85–7.94 (m, 2H), 8.01–8.10 (m, 2H). 13C NMR (CDCl3):
d = 29.79, 37.03, 37.22, 121.26, 128.27, 128.41, 128.68, 128.80,
130.40, 131.36, 133.36, 133.40, 133.64, 136.89, 137.29, 193.45,
196.95. MS (EI, 70 eV, for 79Br): m/z (%) = 299 (50), 220 (14), 192
(15), 115 (16), 105 (100), 77 (59).

C. Peppe et al. / Journal of Organometallic Chemistry 693 (2008) 3441–3445
3445
c-1,t-2-Dibenzoyl-r-3-n-propylcyclopropane (6g): Yellowish oil.
Acknowledgments
1H NMR (CDCl3): d = 0.75 (t, J = 7.2 Hz, 3H), 1.13–1.33 (m, 2H),
1.41–1.55 (m, 2H), 2.18–2.26 (m, 1H), 3.42 (dd, J = 4.6, 9.6 Hz,
1H), 3.48 (dd, J = 4.6, 5.8 Hz, 1H), 7.35–7.41 (m, 4H), 7.44–7.50
(m, 2H), 7.95–7.99 (m, 4H). 13C NMR (CDCl3): d = 13.63, 22.48,
27.87, 31.57, 35.10, 35.28, 128.17, 128.19, 128.52, 128.53, 133.09,
133.15, 137.04, 137.57, 195.76, 197.78. MS (EI, 70 eV): m/z
(%) = 292 [M]+ (3), 187 (100), 170 (8), 145 (6), 105 (100), 77 (100).
trans-2-Benzoyl-3-phenyl-1,1-dicyanocyclopropane (6h) [13,14]:
Colorless solid; m.p. 129–130 °C (lit. 134–135 °C) 1H NMR (CDCl3):
d = 3.83 (d, J = 8.1 Hz, 1H), 3.99 (d, J = 8.1 Hz, 1H), 7.28–7.70 (m,
8H), 8.01–8.05 (m, 2H). 13C NMR (CDCl3): d = 15.20, 35.49, 38.62,
111.54, 112.14, 128.29, 128.70, 129.27, 129.28, 129.41, 129.77,
135.04, 135.34, 188.84. MS (EI, 70 eV): m/z (%) = 140 (8), 105
(100), 77 (89).
C.P. thanks CNPq for financial support, and R.P.D. for the award
of a scholarship.
References
[1] For a discussion on the oxidative insertion reactions of indium(I) compounds
see: C. Peppe, Curr. Org. Synth. 1 (2004) 227.
[2] (a) C. Peppe, R.P. das Chagas, Synlett (2004) 1187;
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89 (1989) 165.
trans-2-Benzoyl-3-(40-chlorophenyl)-1,1-dicyanocyclopropane (6i)
[13]: Colorless solid; m.p. 179–180 °C (decomposition) (lit. 179–
180 °C). 1H NMR (CDCl3): d = 3.81 (d, J = 8.1 Hz, 1H), 3.95 (d,
J = 8.1 Hz, 1H), 7.22–7.71 (m, 7H), 7.98–8.07 (m, 2H). 13C NMR
(CDCl3): d = 15.18, 35.53, 37.76, 111.25, 111.97, 127.93, 128.74,
129.37, 129.60, 129.68, 135.19, 135.23, 136.02, 188.48. MS (EI,
70 eV, for 35Cl): m/z (%) = 165 (3), 105 (100), 77 (49).
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(b) R.E. Taylor, F.C. Engelhardt, M.J. Schmitt, Tetrahedron 59 (2003) 5623.
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see: H. Lebel, J.-F. Marcoux, C. Molinaro, A.B. Charette, Chem. Rev. 103 (2003)
977;
(b) H. Pellissier, Tetrahedron 64 (2008) 7041.
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trans-2-Benzoyl-3-(40-methoxyphenyl)-1,1-dicyanocyclopropane
(6j) [13]: Colorless solid; m.p. 160–162 °C (decomposition) (lit.
161–162 °C).1H NMR (CDCl3): d = 3.76 (s, 3H), 3.79 (d, J = 8.0 Hz,
1H), 3.94 (d, J = 8.0 Hz, 1H), 6.87–6.93 (m, 2H), 7.19–7.27 (m,
2H), 7.49–7.71 (m, 3H), 8.00–8.06 (m, 2H). 13C NMR (CDCl3):
d = 15.31, 35.70, 38.52, 55.37, 111.64, 112.35, 114.71, 121.11,
128.70, 129.29, 129.56, 135.02, 135.39, 160.61, 188.93. MS (EI,
70 eV): m/z (%) = 302 [M]+ (1), 105 (100), 77 (34).
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9061.