Multimetallic Ir-Sn3-catalyzed substitution reaction of π-activated alcohols with carbon and heteroatom nucleophiles

Article abstract of DOI:10.1016/j.tet.2012.10.086

An atom economic and catalytic substitution reaction of π-activated alcohols by a multimetallic IreSn₃ complex has been demonstrated. The multimetallic IreSn₃ complex can be easily synthesized from the reaction between [Cp*IrCl₂]₂ and SnCl2. In presence of as little as 1 mol % of the catalyst three different types of π-activated alcohols, namely benzyl, allyl, and propargyl alcohols, have been successfully transformed into alkylated products using carbon (arenes, heteroarenes, allyltrimethylsilane, and 1,3-dicarbonyls), nitrogen (sulfonamides), oxygen (alcohols), and sulfur (thiols) nucleophiles in very high yields. An electrophilic mechanism is proposed from the Hammett correlation study.

Full text of DOI:10.1016/j.tet.2012.10.086

Tetrahedron 69 (2013) 942e956
Contents lists available at SciVerse ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Multimetallic IreSn3-catalyzed substitution reaction of
p-activated
alcohols with carbon and heteroatom nucleophiles
,
,
Arnab Kumar Maity a, Paresh Nath Chatterjee a y, Sujit Roy b
*
a Organometallic & Catalysis Laboratory, Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India
b School of Basic Sciences, Indian Institute of Technology, Bhubaneswar 751013, India
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 27 August 2012
Received in revised form 3 October 2012
Accepted 3 October 2012
Available online 8 November 2012
An atom economic and catalytic substitution reaction of
p
-activated alcohols by a multimetallic IreSn3
complex has been demonstrated. The multimetallic IreSn3 complex can be easily synthesized from the
reaction between [Cp IrCl2]2 and SnCl2. In presence of as little as 1 mol % of the catalyst three different
types of -activated alcohols, namely benzyl, allyl, and propargyl alcohols, have been successfully
*
p
transformed into alkylated products using carbon (arenes, heteroarenes, allyltrimethylsilane, and 1,3-
dicarbonyls), nitrogen (sulfonamides), oxygen (alcohols), and sulfur (thiols) nucleophiles in very high
yields. An electrophilic mechanism is proposed from the Hammett correlation study.
Ó 2012 Elsevier Ltd. All rights reserved.
1. Introduction
a multimetallic complex, [Cp Ir(SnCl3)2{SnCl2(H2O)2}] 2, bearing
*
‘IreSn3’ motif has been synthesized where, unlike 1, two SnClꢀ3 li-
Design, synthesis, and application of the multimetallic com-
plexes have attracted more interest in homogeneous catalysis re-
cently as they have been found to be more advantageous than their
individual partners in terms of reactivity and selectivity.1 The
phenomenon can be achieved through a suitable combination of
compatible metal centers as well as their ligand frameworks. Sev-
eral examples have been reported in the literature over the above
concepts.2 In this particular field, considerable effort has been
expended from our group to synthesize better catalytic systems
within multimetallic regime for electrophilic activations.3 A het-
gands are attached to the central iridium atom.4 Complex 2 was
found to be an excellent catalyst for
-hydroxylactams.
In nucleophilic substitution reactions there has been growing
interest in using alcohols (water being the only by-product) instead
of halides as the alkylating agents. However the designing of such
a catalyst is challenging because (i) alcohols are less activated as an
alkylating agent than halides due to bad leaving group ability of
hydroxyl moiety, (ii) deactivation of Lewis acidic catalyst takes
place by water, which is also a side-product of the reaction. Partial
a-amidoalkylation reaction of
g
erobimetallic complex, [(COD)Ir(SnCl3)Cl(
m-Cl)]2 1, was prepared
solution to this problem can be achieved by using p-activated al-
via an oxidative addition of SnCl4 across [(COD)IrCl]2 and it was
anticipated that the bimetallic ‘IreSnCl3’ motif may be the key re-
sponsive core for the substrate activation.3a It was indeed observed
that catalytic activities of 1 were much better than the conventional
Lewis or Brønsted acid catalysts toward FriedeleCrafts-type alkyl-
ation reactions. To extend the idea, a new class of catalysts can be
envisaged where multiple centers coordinate to bring a stronger
activation of the substrate and offer superior activity. Such multisite
interaction between adjacent metal centers was observed in cluster
catalysis where a metalemetal bond is viewed as the edge of the
cluster, while three metal centers can comprise a face. Thus
cohols as the alkylating agents along with unusual Lewis acid like
lanthanide metal complexes or different Brønsted acidic like chiral
phosphoric acid catalysts. The
ganic compounds, which have
OH group. In the catalytic nucleophilic substitution reactions cat-
alysts activate the CeOH bond and the adjacent -systems help in
stabilizing the emerging carbocationic species. Benzyl, allyl, and
propargyl alcohols are most easily available -activated alcohols,
p-activated alcohols are those or-
p
-electronic systems adjacent to the
p
p
which contain C]C, C^C, aromatic ring, or a combination of these
three as the stabilizing hands (Scheme 1).5
Triflate and halide derivatives of rare earth as well as post-
transition metals are most widely used catalytic systems for effi-
cient benzylation, allylation, or propargylation with varieties of
nucleophiles. Some transition metal complexes were also reported
for efficient alkylation reactions.6e9 Among them, a very recent ex-
ample of Ga(OTf)3-catalyzed direct displacement of alcohols with
sulfur nucleophiles is interesting.6c In 2005 Beller and co-workers
* Corresponding author. Tel.: þ91 674 2676021; fax: þ91 674 2306303; e-mail
addresses: sroychem@iitbbs.ac.in, sujitroy.chem@gmail.com (S. Roy).
y
Present address: Department of Basic Sciences and Humanities, Techno India
Salt Lake, EMd4/1, SectordV, Salt Lake, Kolkata 700091, India.
0040-4020/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2012.10.086

A.K. Maity et al. / Tetrahedron 69 (2013) 942e956
943
Scheme 1. Catalytic nucleophilic substitution reactions of
p-activated alcohols.
Fig. 1. (A) Solid state structure of 2. H-atoms are not shown for clarity. (B) Proposed
electrophilic activation model involving 2. R-Y¼alkylating agent, Nu¼nucleophile.
documented the utility of 10 mol % FeCl3 in FriedeleCrafts benzy-
lation of different arenes and heteroarenes with good to excellent
yields.6f Later many research groups employed FeCl3 for catalytic
allylation and propargylation reaction with carbon- and
heteroatom-centered nucleophiles.7n,8e Baba group has successfully
reported InCl3 (5 mol %)-catalyzed benzylation and allylation by
different types of silyl and 1,3-dicarbonyl nucleophilies.6e,6g First
complex 2 remained catalytically active for a wide range of tem-
perature from 50 ꢁC to 80 ꢁC (entries 2e4). Variation of catalyst
concentration showed that, a minimum of 0.5 mol % catalyst
loading was required for successful benzylation (entry 5). Similarly,
a wide variety of solvents were tested and except tetrahydrofuran,
solvents like dichloromethane, acetonitrile, nitromethane, and
toluene were found to be equally effective (entries 1e9). The cat-
alytic activity of 2 was uninterrupted even after 15 consecutive
cycles without any loss of TOF. Most important feature is that, the
catalyst can be easily separated and recycled, as it crystallizes out
from the reaction solution after the completion of the reaction. It
may be noted that, complex 2 is air and moisture stable and the
reaction can be carried out using undried and undistilled solvents
in air, without any loss of activity. The heterobimetallic catalyst 1
was tested for its catalytic activity toward the benzylation reaction,
bimetallic catalyst for substitution of
accounted in 2000 by Nishibayashi group as a series of thiolate-
bridged diruthenium complexes such as [Cp RuCl(m2-SR2)RuCp Cl]
p-activated alcohols was
*
*
i
(R¼Me, Et, nPr or Pr) for propargylation of terminal propargyl al-
cohols with a variety of nucleophiles.2b Later they observed that the
cationic versions of the diruthenium complexes are also potent for
the catalytic allylation reactions of aromatic compounds.2j Sub-
sequently, another set of heterobimetallic Group IV(Ti, Zr, Hf)eRu
complexes was also synthesized recently by the same team for the
propargylation reactions.2k
2. Results and discussions
Table 1
Screening of catalysts and optimization of reaction conditions for benzylation
In continuation to our exploration on multimetallic catalysis, we
report here the multimetallic piano-stool IreSn3 complex 2-cata-
lyzed benzylation, allylation, and propargylation reactions with
various types of carbon (arenes, heteroarenes, 1,3-dicarbonyls, and
allyl-TMS), nitrogen (sulfonamides), oxygen (alcohols), and sulfur
(thiols) nucleophiles.
reactiona
#
Catalyst
Loading Solvent T (ꢁC) t, (min) Yieldb TOF
The multimetallic IreSn3 complex 2 was synthesized via in-
sertion reaction of SnCl2 across the iridium-chlorine bonds of
(mol %)
(%)
(hꢀ1
)
1
2
3
4
5
6
7
8
2
2
2
2
2
2
2
2
2
1
1
1
1
1
1
0.5
1
1
1
1
1
1
1
1
1
5
5
5
5
5
5
5
5
5
d
C2H4Cl2 80
C2H4Cl2 70
C2H4Cl2 60
C2H4Cl2 50
C2H4Cl2 70
5
15
45
180
30
15
15
15
360
15
360
15
360
360
360
360
360
360
360
360
360
360
360
360
99
99
99
99
99
96
88
99
5
10
45
95
10
2
1188
396
132
33
198
384
352
396
0.8
40
7.5
380
1.7
[Cp
IrCl2]2 in dichloroethane at 80 ꢁC (Scheme 2).4 After the re-
*
action was completed (ca. 3 h) the greenish yellow solution was
taken out and upon slow diffusion of n-hexane to this solution the
product 2 crystallized out as greenish yellow blocks in good yield.
MeCN
70
MeNO2 70
PhMe
THF
70
60
90
90
90
70
50
9
10c
11
PhMe
PhMe
PhMe
PhMe
PhMe
12d [Ir(COD)Cl]2þ4SnCl4
13 [Ir(COD)Cl]2þ4SnCl4
14 [Ir(COD)Cl]2þ4SnCl4
0.3
0
0
15 [Cp
16 SnCl2
17 SnCl4
18 InCl3
*
IrCl2]2
C2H4Cl2 70
C2H4Cl2 70
C2H4Cl2 70
C2H4Cl2 70
C2H4Cl2 70
C2H4Cl2 70
C2H4Cl2 70
C2H4Cl2 70
C2H4Cl2 70
C2H4Cl2 70
0
0
Scheme 2. Synthesis of multimetallic IreSn3 complex 2.
25
40
40
15
35
30
25
0
4.2
6.7
6.7
2.5
5.8
5.0
4.2
0
As depicted in Fig. 1A, 2 adopts a near perfect three-legged pi-
ano-stool geometry, as is common to the Cp Ir(III) complexes. We
*
19 FeCl3
believe that the piano-stool geometry having three IreSn bonds
may hold the key to superior catalytic activity of 2 toward the
substitution reactions since the three tin centers can provide an
interactive face to bind the alkylating agent ReOH (Fig. 1B).
Initially, the benzylation of toluene 3b with para-methylbenzyl
alcohol 10a was selected as the model reaction and it was observed
that 1 mol % of complex 2 can promote the benzylation reaction
quantitatively affording 99% of ditolylmethane 13a (o/p¼32:68)
just after 5 min at 80 ꢁC (Table 1, entry 1). It was observed that,
20 Sc(OTf)3
21 La(OTf)3
22 Yb(OTf)3
23 Cu(OTf)2
24 No catalyst
a
Reaction conditions: 3b (1.0 mmol), 10a (0.5 mmol), catalyst (0.005 mmol for
1 mol % loading), solvent (2 mL).
b
Determined by GC.
Prepared according to Ref. 3a.
Generated in situ according to Ref. 3a.
c
d

944
A.K. Maity et al. / Tetrahedron 69 (2013) 942e956
however, it was found that, 1 mol % of complex 1 can afford the
product 13a (o/p¼19:81) only in 45% yield after 6 h (entry 10). In-
terestingly, a 1:4 mixture of [Ir(COD)Cl]2 and SnCl4 was found to be
more effective and yielded the product in 95% yield in 15 min at
90 ꢁC. At lower temperature, however, the conversions were found
to be very poor (entries 12e14). Under this similar condition, va-
rieties of Lewis acidic metal (Sc, Yb, La, Cu) triflates and metal (In,
Fe, Sn) halides were tested for the catalytic activity, but none of
them were found to be as effective as 2 (entries 15e23).
Encouraged by these observations, a number of nucleophiles
were tested toward the alkylation with benzyl, allyl, and propargyl
alcohols (Charts 1 and 2). Next, the scope of benzylation of different
primary, secondary, and tertiary benzyl alcohols was evaluated
with an array of carbon nucleophiles like arenes, heteroarenes, 1,3-
dicarbonyls, 4-hydroxycoumarine, etc.
obtained as a mixture of two regioisomers in 69:31 ratio. The
1,3-dicarbonyl derivatives 5bed may also act as potential nucleo-
philes in benzylation reactions but they also serve as bidentate
ligands to decrease the Lewis acidity of the metal catalyst. How-
ever, the IreSn3 complex 2 was found to be effective when dicar-
bonyl compounds were used as nucleophiles and various 2ꢁ benzyl
alcohols were efficiently converted to the benzylated products
13len in excellent yields (entries 12e14). It is very important to
note that 2ꢁ benzyl alcohols 10e and 10g with methyl substituent
underwent the substitution reaction in the presence of catalyst 2
with no elimination products. Not only that, p-bromobenzyl alco-
hol also quantitatively converted to coumarine derivative 13o
when reacted with 4-hydroxycoumarine in optimal conditions
(entry 15). In addition to carbon nucleophiles, various heteroatom
nucleophiles were tested. Sulfonamides (8a and 8b) were alkylated
Chart 1. List of active nucleophiles used in this work.
Chart 2. List of
p-activated alcohols used in this work.
The reaction of benzyl alcohol 10b, and para-substituted benzyl
alcohols 10a (p-Me), 10c (p-Cl), and 10d (p-Br) with p-xylene 3c
was found to afford the corresponding diarylmethanes 13bee in
92e96% yields (Table 2, entries 2e5). Anisole 3d could produce the
ortho and para mixture of diarylmethane derivative 13f quantita-
tively within just 10 min at 70 ꢁC (entry 6). Benzene 3a was found
to be equally effective and afforded benzylarene 13g in excellent
yield (entry 7). We further probed the efficacy of 2 in the
present alkylation reaction for heteroarenes like thiophene 4a,
2-methylthiophene 4b, or 2,5-dimethylfuran 4e and here also the
corresponding products 13iek were obtained in excellent yields
(entries 9e11). In case of thiophene, coupled product 17i was
using 2ꢁ benzyl alcohols to obtain sulfonamide derivatives 13p and
13q in good yields (entries 16 and 17). It was also found that ether
13r and thioethers (13s and 13t) were formed in excellent yield
when alcohols and thiols were used as nucleophiles (entries
18e20). Here it is noteworthy to mention that unlike 1ꢁ benzyl
alcohols for 2ꢁ and 3ꢁ benzyl alcohols catalytic activation by 2 can
be done even at room temperature and products were isolated in
excellent yields.
Encouraged by the results obtained with benzyl alcohols, we
thought to explore catalytic allylation reaction. Optimization of the
reaction conditions and screening of different Lewis acidic catalyst
was carried out taking cinnamyl alcohol 11b and anisole 3d as the

A.K. Maity et al. / Tetrahedron 69 (2013) 942e956
Table 2 (continued )
945
Table 2
Scope of benzylation reaction catalyzed by 2a
#
Substrates
Major product
Yieldb (%)
16
10bþ8b
86
85
#
Substrates
Major product
Yieldb (%)
96
17
10cþ8a
1c
10aþ3b
18e
10gþ7a
90
95
2
10aþ3c
10bþ3c
10cþ3c
10dþ3c
96
95
95
92
3
19e
10fþ9b
10gþ9c
4
5b
20e
94
6d
7
10bþ3d
10aþ3a
96
94
a
Reaction conditions: 3e9 (1.0 mmol), 10 (0.5 mmol), 2 (0.005 mmol), C2H4Cl2
(2 mL).
b
c
d
e
f
Isolated yield after column chromatography.
Regioisomers: ortho/para¼32:68.
Regioisomers: ortho/para¼36:64.
Reaction was carried out at RT.
Ratio of the regioisomers of 13i¼69:31.
8e
10eþ3d
94
substrates. The results again showed the superiority of catalyst 2,
and allylation reaction proceeded under mild condition at room
temperature with almost quantitative yield of the allylation prod-
uct. This encouraged us to extend the scope of 2-catalyzed allyla-
tion reactions with different carbon and heteroatom nucleophiles.
Initially, the allylic substitution of various allyl alcohols was ex-
amined with different carbon-centered nucleophiles (arenes, het-
eroarenes, and 1,3-dicarbonyl compounds) in dichloromethane at
room temperature in the presence of 1 mol % catalyst 2 (Table 3,
entries 1e11 and 19e22). For convenience, the alcohol/nucleophile
ratio was kept at 1:2, and the corresponding allylation products
were isolated in good to excellent yields.
9f
10cþ4a
10aþ4b
96
94
10
11e
10fþ4e
96
Allyl alcohols bearing aryl substituent 11aed smoothly un-
derwent the coupling reaction with arenes like anisole 3d with very
high regioselectivity and the alkylated products 14aed were ob-
tained in excellent yields (entries 1e4). Heteroarenes like thiophene
produced allylationproducts 14e as a mixture of regioisomers and 2-
methylfuran also gave the product 14f with very highyield (entries 5
and 6). Next, the reactions of allyl alcohols with 1,3-dicarbonyl
compounds were explored. High yields of the products 14gej were
obtained from the reaction with cinnamyl alcohol 11b or 2ꢁ allyl
alcohol 11e and 1,3-dicarbonyls like 5bed (entries 7e\10). Special
type of 1,3-dicarbonyl compound like 4-hydroxycoumarin 5a was
also found to be an active nucleophile and produced the allylated
coumarine derivative 14k with good yield (entry 11). To explore the
generality of the reaction further, the reaction of allyl alcohols with
heteroatom nucleophiles was tested. With 1 mol % loading of 2,
desired ethers 14l and 14m were obtained in high yields from the
reactions of allyl alcohols with ethanol and t-butyl alcohol as oxygen
nucleophile (entries 12 and 13). For representative nitrogen-
nucleophiles, the reactions between sulfonamides 8bed and cin-
namyl alcohol 11b were selected and the allylated sulfonamide
12e
13e
10gþ5c
10eþ5d
90
88
14e
10eþ5b
10aþ5a
88
86
15

946
A.K. Maity et al. / Tetrahedron 69 (2013) 942e956
Table 3 (continued)
Table 3
Scope of allylation reaction catalyzed by 2a
#
Substrates
Major product
Yieldb (%)
80
16
11bþ8d
#
1
Substrates
Major product
Yieldb (%)
96
11aþ3d
17
18
11bþ9b
11bþ9c
96
96
2
11bþ3d
11cþ3d
11dþ3d
11bþ4a
92
90
90
94
3
4
19
20
21
11gþ3c
11gþ3d
11gþ3f
11hþ3c
83
82
88
85
5c
6
7
11bþ4d
11bþ5d
95
93
22
8
11bþ5b
11bþ5c
11eþ5d
92
93
88
a
Reaction conditions: 3e9 (1.0 mmol), 11 (0.5 mmol), 2 (0.005 mmol), CH2Cl2
(2 mL).
b
c
Isolated yield after column chromatography.
Ratio of the regioisomers in 14e¼72:28.
9
products 14nꢀp were obtained in good to excellent yields (entries
14e16). Similarly, carbonesulfur bonds were successfully made
using sulfur nucleophiles like t-butyl thiol 9b or p-methoxy thio-
phenol 9c (entries 17 and 18). No FriedeleCrafts-type arylated
product was observed in case of p-methoxy thiophenol, the exclu-
sive product was thioether 14r. In addition to aryl substituted allyl
alcohols, alkyl substituted allyl alcohols like crotyl alcohol 11g were
also subjected to alkylation reaction with p-xylene, anisole, or 1,3,5-
trimethoxy benzene and the allylated products 14seu were isolated
in good yield (entries 19e21). Similarly, hex-2-en-1-ol 11h on re-
action with p-xylene produced the corresponding allylated product
14v in good yield (entry 22).
10
11
11fþ5a
83
12
13
11bþ7a
11bþ7b
83
92
As an obvious extension of benzylation and allylation reaction, it
was thought worthwhile to study 2-catalyzed ‘true propargylation’
reactions. Here the word ‘true propargylation’ is referred to the kind
of propargylic activation (Scheme 3, type-I) where the propargylic
carbocationic species are not stabilized by adjacent aromatic ring. It
may be noted that, such propargylic substitution reactions are more
challenging because of two reasons: (i) emerging cationic species
after catalytic activation of CeOH bond is stabilized by only prop-
14
15
11bþ8b
11bþ8c
92
87
argylic
p-systems, (ii) high possibility of b-H elimination to form
enyne compounds. In this context, our goal was to optimize the
conditions for propargylation reaction catalyzed by 2 so that the
yield the propargylated products in the true propargylation re-
actions could be maximized. Keeping this in view, the model

A.K. Maity et al. / Tetrahedron 69 (2013) 942e956
947
Scheme 3. Concept of true propargylation reaction.
reaction between 2-methyl-4-phenyl-but-3-yn-2-ol 12b (having
b
-
Finally, when sterically bulkier nucleophile like 1,3,5-
trimethoxy benzene 3f was employed for alkylation with 3ꢁ prop-
argylic alcohol then normal propargylic product was not obtained,
instead a substituted indene (17a and 17b) was exclusively formed
(Scheme 5). The fact that, the key factor behind this unusual
transformation is purely steric was proved by the following results:
(a) 1,2,3-trimethoxy benzene 3e gave usual propargylic substituted
product 15f with 3ꢁ propargyl alcohol; while (b) 1,3,5-trimethoxy
benzene 3f provided usual propargylated product 15g with 2ꢁ
propargylic alcohol. The indene formation can be explained by
H) as representative alcohol and anisole 3d as the arene was se-
lected in presence of 1 mol % of multimetallic catalyst 2 and in di-
chloroethane as solvent. The results are briefly summarized in
Scheme 4. From the optimization results it was found that the
chance of elimination reaction to produce enyne product could be
minimized by increasing the nucleophile to alcohol ratio and by
decreasing reaction temperature to 60 ꢁC from 80 ꢁC. Under this
particular circumstance the obtained yield of the propargylated
product 15b was found to be 85%.
Scheme 4. Optimization of reaction conditions for propargylation reaction.a
After establishing optimal conditions for ‘true propargylation’,
the generality of this reaction was tested using various arenes and
heteroarenes and different propargylic alcohols under the opti-
mized condition and the results are given in Table 4. Anisole was
alkylated by four para-substituted 3ꢁ propargylic alcohols 12aed in
good yield (entries 1e4). Unlike 3ꢁ alcohols, activation of 2ꢁ
propargylic alcohol 12e and 12f by 2 was slow and using different
nucleophiles like anisole, 1,3,5-trimethoxy benzene, or allyl-
trimethylsilane the alkylated products 15e, 15g, and 15m were
isolated in 65e73% yield after 6 h along with w20% unreacted
starting material (entries 5, 7, and 13). Notably, when phenol was
used as a nucleophile for 2ꢁ propargylation with 12f the sole
product was 15h, no ether type product by an attack from phenolic
oxygen atom was observed (entry 8). Heteroaromatics like thio-
phenes, 2-methylthiophene, furan, and benzo[b]furan also gave
propargylated products 15iel in good yields (entries 9e12).
In all the cases mentioned above it was found that the prop-
argylation took place only at the most electron rich center of the
aromatic or heteroaromatic compounds. After getting satisfactory
results with aromatic compounds, it was thought to use 1,3-
dicarbonyl compounds as nucleophiles. However, the results were
found to be disappointing. For example, when acetylacetone 5b was
used as the nucleophile only 45% of the coupled product 15n was
obtained along with elimination product (entry 14). In comparison,
heteroatom center nucleophiles like aliphatic thiols, alcohols, and
tosylamine were also successfully tested as potential nucleophiles
and good yields of propargylated products were isolated (entries
15e20). Compound having two activated propargylic alcohol cen-
ters like 12i was successfully activated in presence of just 1 mol % 2
and bis-thioether 15t was isolated as the major product (entry 20).
However, in case of p-methoxy thiophenol no FriedeleCraft type
product was obtained.
assuming prior nucleophilic attack at acetylinic center of prop-
argylic alcohol due to steric reason followed by intramolecular
arylation and subsequent aromatization (Scheme 6).3g
To test the likelihood of an electrophilic mechanism in benzy-
lation, allylation as well as propargylation reaction, kinetic study
was performed for all three types of alkylation reactions using gas
chromatographic technique. From the kinetic study, the relative
rate constant values kR/kH were evaluated. The studies were con-
ducted with four different para-substituted benzyl, allyl, and
propargyl alcohols. The rate kinetic study and related Hammett plot
for benzylation, allylation, and propargylation reaction are dis-
cussed hereafter. Rate studies for benzylation was carried out at
70 ꢁC taking p-xylene and four different para-substituted benzyl
alcohols p-R-C6H4CH2OH (R¼Me, H, Cl, and Br) and from the graph
the corresponding rates for four different benzylation reactions
were calculated (Scheme 7). The kinetic study for allylation was
done at 30 ꢁC taking anisole and four different para-substituted
allyl alcohols p-R-C6H4CH]CHCH2OH (R¼Me, H, Cl, and Br). From
the graph, the corresponding rates for four different allylation re-
actions were obtained (Scheme 8). Finally propargylation reactions
were carried out at 60 ꢁC for the reaction of anisole with para-
substituted propargyl alcohols p-R-C6H4C^C(Me)2OH (R¼Me, H,
Cl, and Br) and from the graph the corresponding rates for four
different propargylation reactions were obtained (Scheme 9).
After obtaining all the rate constant values (kR) for three different
alkylation reactions then the logarithm of (kR/kH) value against
Hammett substituent constants sR was plotted. The linear correla-
tion obtained from these plots resulted in the Hammett reaction
constant r-values (Fig. 2). The reaction constant values for all three
alkylation reactions are moderately negative (between ꢀ2 and ꢀ4).
Specifically the values are ꢀ3.3, ꢀ2.7 and ꢀ2.1 corresponding to
benzylation, allylation, and propargylation, respectively. The

948
A.K. Maity et al. / Tetrahedron 69 (2013) 942e956
Table 4 (continued)
Table 4
Scope of propargylation reaction catalyzed by 2a
#
Substrates
Major product
Yieldb (%)
10
12bþ4b
86
#
1
Substrates
Major product
Yieldb (%)
11
12
12bþ4a
12bþ4f
74
80
12aþ3d
85
13c
14f
15
16
17
18
12fþ6
67
45
78
83
76
78
2
12bþ3d
12cþ3d
12dþ3d
12eþ3d
12bþ3e
85
77
80
65
85
12bþ5b
12bþ7a
12bþ7c
12bþ8b
12gþ8b
3
4
5c,d
6
19
12hþ9a
12iþ9c
86
88
7c
8c
9e
12fþ3f
12fþ3g
12bþ4c
73
67
79
20
a
Reaction conditions: 3e9 (1.5 mmol), 12 (0.5 mmol), 2 (0.005 mmol), C2H4Cl2
(3 mL).
b
c
d
e
f
Isolated yield after column chromatography.
Starting material was recovered up to 15%.
Product was isolated as a mixture of ortho and para isomers.
Furan was used 20 equiv to alcohol.
Enyne product was isolated.

A.K. Maity et al. / Tetrahedron 69 (2013) 942e956
949
Scheme 5. Indene formation versus propargylation reaction: steric factor.
Scheme 6. Plausible reaction mechanism for indene formation.
Scheme 7. Rate constants kBR for the reactions of p-xylene with p-substituted benzyl alcohols.
moderately negative values suggest the possibility of generation of
weak positivecharge (
due to the coordination of alcoholic eOH group to the [IreSn3] motif
activated alcohols. The screening of other Lewis acidic catalytic
systems for benzylation reaction and subsequent optimization
studies showed that 2 is better in terms of selectivity, product yield,
TOF, and catalyst loading. It was also observed that 2 is superior to
our previously designed heterobimetallic catalyst 1a. Keeping this
in mind, the nucleophilic substitution reactions of benzyl, allyl, and
propargyl alcohols with different types of carbon nucleophiles
(arenes, heteroarenes, allyltrimethylsilane, 1,3-dicarbonyls etc.),
nitrogen-nucleophiles (sulfonamides), oxygen nucleophiles (alco-
hols), sulfur nucleophiles (thiols) were carried out in presence of
d
þ) at the reactive carboncenterof the alcohol
of the catalyst.
3. Conclusions
In summary, the present study demonstrated the superior effi-
ciency of the multimetallic catalyst Cp
*
Ir(SnCl3)2{SnCl2(H2O)2} 2
toward nucleophilic substitution reaction of three different
p-

950
A.K. Maity et al. / Tetrahedron 69 (2013) 942e956
Scheme 8. Rate constants kAR for the reactions of anisole with p-substituted allyl alcohols.
0.30
0.25
0.20
0.15
0.10
0.05
0.00
-0.05
0
500 1000 1500 2000 2500 3000 3500 4000
Scheme 9. Rate constants kPR for the reactions of anisole with p-substituted propargyl alcohols.
1 mol % of catalyst 2 and eventually the substitution products were
isolated in good to excellent yields. As a special mention, product
bearing an indene moiety was obtained exclusively when 3ꢁ
propargyl alcohols were reacted with bulky arenes like 1,3,5-
trimethoxy benzene. Finally, the likelihood of electrophilic activa-
NMR spectra were recorded on Bruker-AC 200 MHz and Bruker-
Avance II 400 MHz spectrometer at 300 K. 1H NMR spectra were
recorded at 200 MHz and 400 MHz, chemical shifts are reported in
parts per million (ppm) from tetramethylsilane with the solvent
resonance as the internal standard (CDCl3:
d 7.26 ppm, (CD3)2CO:
tion of three
p-activated alcohols was confirmed using Hammett
d
2.05 ppm, (CD3)2SO: 2.50 ppm). Data are reported as follows:
d
correlation study; the Hammett reaction constant
obtained as moderate negative values for all three alcohols.
r
-values were
chemical shifts, multiplicity (s¼singlet, d¼doublet, t¼triplet,
q¼quartet, br¼broad, m¼multiplet), integration, coupling constant
(Hz).13C NMR spectra were recorded at 54.6 MHz and 100 MHz with
proton decoupling. Chemical shifts are reported in parts per million
from tetramethylsilane with the solvent resonance as the internal
4. Experimental
standard (CDCl3:
d 77.0 ppm, (CD3)2CO: d 29.9 and 206.7 ppm,
4.1. General remarks
(CD3)2SO:
d
39.5 ppm).119Sn NMR spectra were recorded at 149 MHz
and chemical shifts are reported in parts per million with respect to
Sn(CH3)4. FTIR (4000e500 cmꢀ1; using KBr pellet) spectra were
obtained using a PerkineElmer FTIR Spectrometer (Spectrum RX I).
UVevisible spectra were recorded at 298 K on Shimadzu UV-1601
UVeVIS Spectrometer using spectrophotometric grade solvent. El-
emental analyses were performed on PerkineElmer Instruments
2400 Series II CHNS/O Analyzer and Vario EL, Elementar. Melting
All preparations and manipulations have been performed under
an inert atmosphere of argon using standard vacuum lines and
Schlenk techniques. All solvents used for the synthesis have been
dried and distilled by standard methods and previously de-
oxygenated in the vacuum line. Pre-coated silica gel 60F254 (Merck)
was used for thin layer chromatography (TLC) and silica gel 60e120
and 100e200 mesh (SRL) was used for column chromatography.

A.K. Maity et al. / Tetrahedron 69 (2013) 942e956
951
portion. After 30 min stirring at ꢀ78 ꢁC, the solution was slowly
warmed to 0 ꢁC and stirred for 1 h, then cooled to ꢀ78 ꢁC. The re-
action was quenched by dropwise addition of 1 N aqueous HCl. After
warming to RT, additional 6 N HCl and dichloromethane were added
carefully until complete dissolution of the precipitate. The aqueous
phase was extracted twice with dichloromethane and combined
organic phases were dried over Na2SO4. Subsequent solvent removal
under reduced pressure gave the title alcohol as an off-white solid
(78e82% yield), which did not require further purification.
Spectral data of compounds 11a,17 11c,17 and 11d17 were in ex-
cellent agreement with those in the literature.
0.8
0.6
0.4
0.2
0.0
-0.2
-0.4
-0.6
-0.8
Procedure 2:18 The aldehyde (43.2 mmol) was added gradually to
a solution of NaOH (2.2 g) in H2O (20 mL) and ketone (43.3 mmol)
in ethanol (12 mL) at 0 ꢁC. The reaction mass was stirred at RT for
4 h. After 4 h, saturated ammonium chloride solution was added to
the flask, followed by extraction with ether. The combined organic
layers were dried over Na2SO4 and concentrated to give a solid,
which was purified by column chromatography to give pure enone,
which was used in the next step.
-0.2
-0.1
0.0
0.1
0.2
0.3
Fig. 2. Hammett correlation plot with respect to alcohols.
Reduction of enone (0.014 mol) was carried out with sodium
borohydride(0.56 g, 0.015 mol) in methanol(5 mL)for 2 hat 0e10 ꢁC.
After completion of the reaction, the reaction mass was neutralized
with dilute HCl (5%) and extracted with ethyl acetate. The organic
layer was dried over Na2SO4 and evaporated under vacuum. Pure
alcohol was obtained in 85e88% yield after column chromatography
using petroleum ether/ethyl acetate (90:10) as eluent.
points were determined on an Electrothermal 9100 melting point
apparatus and are uncorrected. Single crystal X-ray crystallographic
data were collected on Bruker Smart APEX system that uses graphite
ꢀ
monochromated Mo K
a
radiation (
l
¼0.71073 A). The structure was
solved by direct method and refined by least square method on F2
employing WinGX package and the relevant programs (SHELX-97
and ORTEP-3) implemented therein. Non-hydrogen atoms were
refined anisotropically and hydrogen atoms on carbon atoms were
fixed at calculated positions and refined using a riding model.
Spectral data of compounds 11e15 and 11f15 were in excellent
agreement with those in the literature.
4.2.4. General procedure for the synthesis of propargyl alcohol-
s. Procedure 1:15 To a solution of aryl iodide (25 mmol) in dry THF
(33 mL) was added Et3N (7.29 mL), PdCl2(PPh3)2 (351 mg, 0.5 mmol),
and CuI (327 mg,1.71 mmol) at room temperature. The mixture was
stirred for 30 min and then terminal propargyl alcohol (25 mmol) in
THF (10 mL) was added dropwise. The resulting mixture was stirred
under an argon atmosphere for 6 h after which the suspension
containing the precipitated ammonium salt was passed through
a short 100e200 silica gel column eluting with ether. The solvents
were concentrated, washed with brine, and dried over anhydrous
Na2SO4. The crude product was purified by column chromatography
and 82e90% yield of the title alcohol was isolated.
4.2. Synthesis of starting materials
4.2.1. Synthesis of organometallic complexes. [(COD)Ir(
m
-Cl)2]2,10
Ir(SnCl3)2
[Cp
*
IrCl2]2,11
[(COD)Ir(SnCl3)Cl(
m
-Cl)]2,3a
and
[Cp
*
{SnCl2(H2O)2}],4 were preparedaccordingtotheliteratureprocedures.
4.2.2. General procedure for the synthesis of benzyl alcohols.12 In
a 250 mL two-necked round-bottom flask, equipped with a stirrer
and a dropping funnel, was placed a solution of aldehyde or ketone
(0.1 mol) in 100 mL of methanol. A solution of NaBH4 (1.4 g,
0.037 mol) in 20 mL of 0.2 M NaOH was added at a rate of 0.5 mL/min
with occasional cooling to keep the temperature at 18e25 ꢁC. Upon
completion, the solution was treated cautiously with dilute H2SO4
until the evolution of hydrogen gas ceased. The methanol was re-
moved in a rotatory evaporator, water (50 mL) was added, and the
organic product was extracted twice with ether (2ꢂ50 mL), washed
with brine, and dried over anhydrous Na2SO4. Solvent was removed
to obtain the product as white/yellow solid in 82e92% yields.
Spectral data of compounds 10a,13 10c,13 10d,14 10e,15 10f,15 and
10g15 were in excellent agreement with those in the literature.
Spectral data of compounds 12a,15 12b,15 12c,15 12d,19 12e,20 12f,15
and 12g21 were in excellent agreement with those in the literature.
Procedure 2:15 To a light yellow solution of phenylacetylene
(40 mmol) in Et2O (50 mL) was added 1 equiv of n-butyllithium
(hexane solution, 1.6 M) at ꢀ78 ꢁC. After being stirred for a few
minutes, the dark yellow solution was allowed to warm to 0 ꢁC using
an ice bath. After 15 min, a solution of 1.1 equiv of butanone in Et2O
(40 mL) was slowly added at 0 ꢁC using a dropping funnel. The solu-
tion immediately turned red. After being stirred for 2 h, the thus-
formed yellow solution was quenched with a saturated ammonium
chloride solution. The organic layer was separated from the water
layer. The water layer was extracted twice with diethyl ether. The
combined organic fractions were then dried on anhydrous Na2SO4.
After filtration, the solvent was evaporated. The product was purified
by column chromatography and product was isolated in 75% yield.
Spectral data of compound 12h15 was in excellent agreement
with that in the literature.
4.2.3. General procedure for the synthesis of allyl alcohols. Procedure
1:16 4-Substituted cinnamic acid (10 mmol) and potassium car-
bonate (1.38 g, 10 mmol) were suspended in dimethylformamide
(10 mL). Methyl iodide (2.13 g, 0.93 mL, 15 mmol) was added in one
portion and the mixture was stirred for 2 d or until complete
conversion was observed by TLC. After addition of aqueous satu-
rated ammonium chloride (ca. 10 mL), the mixture was stirred for
30 min, then it was extracted with diethyl ether twice (2ꢂ25 mL).
The combined organic phases were washed twice with brine, then
dried over Na2SO4. After removing the solvent under reduced
pressure, the ester was obtained as an off-white solid, which was
used in the next step without further purification.
Procedure 3:15 AdrySchlenkflaskwas charged withPd/C (0.512 g,
0.5 mmol Pd), CuI (0.192 g, 1 mmol), and PPh3 (0.262 g, 1 mmol),
followed byDMA(9.5mL) andwater(0.5mL). Aftertheaddition of p-
dibromobenzene (2.36 g, 10 mmol), diisopropylamine (2.1 mL), and
2-methyl-3-butyn-2-ol (2.4 mL, 25 mmol), the reaction mixture was
purged with argon, sealed, and placed in an 80 ꢁC oil bath for 24 h.
After the mixture was cooled to ambient temperature, the charcoal
was filtered off and water was added to the solution. The aqueous
To a solution of the ester in dichloromethane (20 mL) at ꢀ78 ꢁC
was added DIBAL (1 M in dichloromethane, 25 mL, 25 mmol) in one

952
A.K. Maity et al. / Tetrahedron 69 (2013) 942e956
phase was extracted with diethyl ether, and the combined organic
phases were dried over anhydrous Na2SO4. After removal of the
solvent in a vacuum, the crude product was purified by column
chromatography and propargyl alcohol was isolated in 68% yield.
Spectral data of compound 12i15 was in excellent agreement
with that in the literature.
J¼8.2 Hz), 7.16e7.39 (m, 5H). 13C NMR (54.6 MHz, CDCl3)
d 41.1, 55.3,
113.9, 125.7, 128.4, 128.8, 129.9, 133.3, 141.6, 158.0.
4.4.7. 1-Benzyl-4-methylbenzene (13g).27 1H NMR (200 MHz, CDCl3)
2.35 (s, 3H), 3.97 (s, 2H), 7.12e7.32 (m, 9H). 13C NMR (54.6 MHz,
CDCl3) 20.9, 41.4,125.9,128.3,128.7,128.8,129.0,135.4,138.0,141.3.
d
d
4.3. General procedure for the screening of various catalysts
and optimization of benzylation reaction
4.4.8. 1-Methoxy-4-(1-p-tolylethyl)benzene
(13h).28 1H
NMR
(200 MHz, CDCl3)
d
1.51 (d, J¼7.2 Hz, 3H), 2.22 (s, 3H), 3.67 (s, 3H),
3.98 (q, J¼7.2 Hz, 1H), 6.71e6.74 (m, 2H), 6.97e7.06 (m, 6H). 13C
A 10 mL Schlenk flask equipped with a magnetic bar was charged
NMR (54.6 MHz, CDCl3) d 21.2, 22.2, 43.6, 55.3, 113.8, 127.4, 128.5,
with catalyst (0.005 mmol for 1 mol % loading), toluene (105
mL,
129.1, 135.4, 138.8, 143.9, 157.8.
1.0 mmol), n-nonane (as internal standard for GC), and solvent
(2 mL). The flask was degassed with argon and placed into a constant
temperaturebath. After the mixturewas stirred vigorouslyfor 5 min,
para-methylbenzyl alcohol (61 mg, 0.5 mmol) was added to it, and
the reaction was allowed to continue at that specified temperature
for 6 h. Known volume of aliquots was withdrawn from the reaction
flask, filtered through a short pad of Celite, diluted with toluene, and
the organic layer was analyzed with GC against n-nonane as internal
standard.
4.4.9. 2-(4-Chlorobenzyl)thiophene (13i).22 1H NMR (200 MHz,
CDCl3)
d
(mixture of isomers) 3.98 (s, 2H), 4.16 (s, 2H), 6.84e6.99
(mixture
(m, 4H), 7.16e7.33 (m, 10H). 13C NMR (54.6 MHz, CDCl3)
d
of isomers) 35.3, 35.8, 121.4, 124.1, 125.3, 125.8, 126.8, 128.2, 128.5,
128.6, 128.9, 129.9, 130.0, 131.9, 132.2, 138.8, 139.0, 140.8, 143.3.
4.4.10. 2-Methyl-5-(4-methylbenzyl)thiophene (13j).29 1H NMR
(200 MHz, CDCl3)
d 2.23 (s, 3H), 2.42 (s, 3H), 3.84 (s, 2H), 6.58 (d,
J¼3.2 Hz, 1H), 6.82 (d, J¼3.2 Hz, 1H), 7.02 (d, J¼7.8 Hz, 2H), 7.16 (d,
4.4. General procedure for the alkylation reaction with
activated alcohols catalyzed by 2
p-
J¼7.8 Hz, 2H).
4.4.11. 3-Benzhydryl-2,5-dimethylfuran (13k).3c 1H NMR (200 MHz,
To a solution of
p
-activated alcohol (0.5 mmol) in 3 mL of di-
CDCl3) d 2.10 (s, 3H), 2.19 (s, 3H), 5.21 (s, 1H), 5.66 (s, 1H), 7.15e7.30
chloroethane or dichloromethane were added under an argon at-
mosphere 2 (5 mg, 0.005 mmol) and nucleophile (1.0 mmol). The
reaction mixture was stirred at a specific temperature oil bath.
When the reaction was over (monitored by TLC using ethyl acetate/
petroleum ether 60e80 ꢁC 1:3 v/v), a saturated aqueous solution of
sodium hydrogen carbonate was added. The aqueous layer was
then extracted two times with dichloromethane (2ꢂ5 mL). The
combined organic layers were dried over sodium sulfate; the sol-
vent was removed under reduced pressure. The resulting product
was purified by column chromatography on silica gel to obtain the
expected coupled products 13, 14, and 15.
(m, 10H). 13C NMR (54.6 MHz, CDCl3)
126.1, 128.2, 128.8, 144.1, 145.8, 149.2.
d 11.7, 13.5, 47.5, 107.7, 121.8,
4.4.12. 1-Phenyl-2-(1-phenylethyl)butane-1,3-dione (13l).3h 1HNMR
(200 MHz, CDCl3)
d
(mixtures of diastereomers) 1.21 (d, J¼6.8 Hz,
3H),1.29 (d, J¼7.0Hz, 3H),1.90 (s, 3H), 2.24(s, 3H), 3.72e3.94 (m,1H),
3.72e3.94 (m, 1H), 4.81 (d, J¼11.2 Hz, 1H), 4.90 (d, J¼11.0 Hz, 1H),
7.06e7.64 (m, 8H), 7.06e7.64 (m, 8H), 7.78 (d, J¼7.2 Hz, 1H), 7.78 (d,
J¼7.2 Hz, 1H), 8.08 (d, J¼7.2 Hz, 1H), 8.08 (d, J¼7.2 Hz, 1H). 13C NMR
(54.6 MHz, CDCl3):
d (mixtures of diastereomers) 20.3, 21.6, 27.6,
27.9, 40.4, 40.9, 70.8, 71.5, 126.6, 127.0, 127.4, 127.5, 128.5, 128.6,
128.9, 133.5, 133.9, 137.1, 137.2, 143.2, 143.5, 195.2 (2C), 203.2, 203.7.
4.4.1. Di-p-tolylmethane (13a).22 1H NMR (200 MHz, CDCl3)
d (ortho
isomer) 2.26 (s, 3H), 2.32 (s, 3H), 3.96 (s, 2H), 7.04e7.17 (m, 8H); (para
4.4.13. 1,3-Diphenyl-2-(1-p-tolylethyl)propane-1,3-dione (13m).3h 1H
isomer) 2.32 (s, 6H), 3.91 (s, 2H), 7.04e7.17 (m, 8H). 13C NMR (54.6 MHz,
NMR (200 MHz, CDCl3)
d
1.32 (d, J¼7.0 Hz, 3H), 2.21 (s, 3H), 4.04 (dq,
CDCl3)
d
(ortho and para isomers) 19.8, 21.1, 39.1, 41.2, 126.1, 126.5, 127.7,
J¼7.0 and 10.2 Hz, 1H), 5.59 (d, J¼10.2 Hz, 1H), 6.98 (d, J¼7.8 Hz, 2H),
7.14 (d, J¼8.2 Hz, 2H), 7.24e7.46 (m, 2H), 7.48e7.60 (m, 4H), 7.74 (d,
J¼7.8 Hz, 2H), 8.03 (d, J¼8.0 Hz, 2H). 13C NMR (54.6 MHz, CDCl3)
128.8, 128.9, 129.2, 129.4, 130.0, 135.5, 136.7, 137.4, 138.5, 139.3.
4.4.2. 1,4-Dimethyl-2-(4-methylbenzyl)benzene (13b).23 1H NMR
d 20.4, 20.9, 40.8, 65.1, 127.6, 128.5, 128.6, 128.8, 129.1, 133.0, 133.5,
(200 MHz, CDCl3)
(m, 7H).
d
2.15 (s, 3H), 2.25 (s, 6H), 3.83 (s, 2H), 6.80e7.00
136.1, 137.0, 137.2, 140.9, 194.7, 195.2.
4.4.14. 3-(1-p-Tolylethyl)pentane-2,4-dione
(13n).3h 1H
NMR
4.4.3. 2-Benzyl-1,4-dimethylbenzene (13c).23 1H NMR (200 MHz,
CDCl3)
2.22 (s, 3H), 2.31 (s, 3H), 3.97 (s, 2H), 6.96e7.30 (m, 8H). 13
(200 MHz, CDCl3)
d
1.18 (d, J¼7.0 Hz, 3H), 1.84 (s, 3H), 2.26 (s, 3H),
d
C
2.29 (s, 3H), 3.55 (dq, J¼7.0 and 11.4 Hz, 1H), 4.01 (d, J¼11.4 Hz, 1H),
NMR (54.6 MHz, CDCl3) 19.1, 20.9, 39.4, 125.8, 127.0, 128.3, 128.6,
130.2, 130.7, 133.4, 135.3, 138.6, 140.5.
7.04e7.12 (m, 4H). 13C NMR (54.6 MHz, CDCl3)
d 20.9, 29.7, 40.1,
76.5, 127.1, 129.4, 136.4, 140.0, 203.6.
4.4.4. 2-(4-Chlorobenzyl)-1,4-dimethylbenzene (13d).24 1H NMR
4.4.15. 4-Hydroxy-3-(4-methylbenzyl)-2H-chromen-2-one
(13o).30 1H NMR (200 MHz, CDCl3)
2.37 (s, 3H), 4.15 (s, 2H), 6.05
(s, 1H), 7.11e7.41 (m, 6H), 7.47e7.55 (m, 1H), 7.64 (d, J¼8.0 Hz, 1H).
13C NMR (54.6 MHz, CDCl3)
21.1, 40.4, 110.2, 116.2, 116.4, 123.0,
(200 MHz, CDCl3)
7H).
d
2.20 (s, 3H), 2.32 (s, 3H), 3.95 (s, 2H), 6.95e7.32 (m,
d
d
4.4.5. 2-(4-Bromobenzyl)-1,4-dimethylbenzene (13e).25 1H NMR
123.9, 127.3, 130.3, 131.8, 137.4, 138.6, 152.5, 160.1, 163.7.
(200 MHz, CDCl3)
(m, 7H).
d 2.18 (s, 3H), 2.34 (s, 3H), 3.99 (s, 2H), 6.88e7.32
4.4.16. N-Benzyl-4-methylbenzenesulfonamide (13p).31 1H NMR
(200 MHz, CDCl3)
d
2.33 (s, 3H), 4.10 (d, J¼6.2 Hz, 2H), 5.24 (m, 1H),
4.4.6. 1-Benzyl-4-methoxybenzene (13f).26 ortho Isomer: 1H NMR
(200 MHz, CDCl3)
3.87 (s, 3H), 4.03 (s, 2H), 6.90e7.36 (m, 9H). 13
NMR (54.6 MHz, CDCl3) 35.9, 55.4, 110.5, 120.5, 125.8, 127.5, 128.3,
129.0, 129.7, 130.4, 141.1, 157.4; para isomer: 1H NMR: (200 MHz,
CDCl3)
3.81 (s, 3H), 4.07 (s, 2H), 6.86 (d, J¼8.2 Hz, 2H), 7.14 (d,
7.19e7.33 (m, 7H), 7.81 (d, J¼8.0 Hz, 2H). 13C NMR (54.6 MHz, CDCl3)
d
C
d 21.4, 46.9, 127.1, 127.8, 127.9, 128.5, 129.5, 136.3, 137.1, 143.3.
d
4.4.17. N-(4-Chlorobenzyl)benzenesulfonamide (13q).32 1H NMR
(200 MHz, CDCl3)
4.05 (d, J¼6.3 Hz, 2H), 5.42 (m,1H), 7.19e7.29 (m,
d
d

A.K. Maity et al. / Tetrahedron 69 (2013) 942e956
953
4H), 7.42e7.58 (m, 3H), 7.81 (d, J¼7.8 Hz, 2H). 13C NMR (54.6 MHz,
(100 MHz, CDCl3)
126.1,127.0,127.4,127.6,128.4,130.0,132.6,136.7,136.9,191.7, 203.8.
d
23.1, 29.3, 30.4, 31.6, 68.3, 107.3, 125.4, 126.0,
CDCl3)
d
46.2, 126.8, 128.7, 129.1, 129.4, 132.1, 133.5, 134.2, 139.9.
4.4.18. (1-Ethoxyethyl)benzene (13r).33 1H NMR (200 MHz, CDCl3)
4.4.29. 2-Cinnamyl-1-phenylbutane-1,3-dione (14i).37 1H NMR
d
1.23 (t, J¼7.2 Hz, 3H), 1.46 (d, J¼6.6 Hz, 3H), 3.40 (q, J¼7.2 Hz, 2H),
(400 MHz, CDCl3)
1H), 6.11e6.21 (m, 1H), 6.50e6.55 (m, 1H), 7.20e7.30 (m, 5H),
d
2.15 (s, 3H), 2.80e2.90 (m, 2H), 4.60 (t, J¼7.2 Hz,
4.45 (q, J¼6.6 Hz, 1H), 7.26e7.41 (m, 5H). 13C NMR (54.6 MHz,
7.45e7.50 (m, 2H), 7.55e7.65 (m, 1H), 8.01e8.05 (m, 2H). 13C NMR
CDCl3)
d 15.2, 23.1, 63.0, 77.9, 126.2, 127.2, 128.4, 128.6, 144.2.
(100 MHz, CDCl3)
128.7, 128.8, 132.2, 133.5, 136.1, 136.9, 195.5, 203.3.
d 28.1, 32.2, 62.9, 125.5, 126.0, 126.2, 127.3, 128.4,
4.4.19. Benzhydryl(tert-butyl)sulfane (13s).34 1H NMR (200 MHz,
CDCl3)
1.26 (s, 9H), 5.21 (s, 1H), 7.15e7.46 (m, 10H). 13C NMR
(54.6 MHz, CDCl3) 31.3, 52.2, 126.7, 128.3, 128.4, 143.2.
d
d
4.4.30. (E)-2-(4-(4-Bromophenyl)but-3-en-2-yl)-1,3-diphenylpropane-
1,3-dione (14j).3i 1H NMR (200 MHz, CDCl3)
d
1.23 (d, J¼6.8 Hz, 3H),
4.4.20. (4-Methoxyphenyl)(1-phenylethyl)sulfane (13t).35 1H NMR
3.51e3.70 (m, 1H), 5.35 (d, J¼8.0 Hz, 1H), 6.06e6.17 (dd, J¼8.0 and
16.0 Hz, 1H), 6.31 (d, J¼16.0 Hz, 1H), 6.98 (d, J¼8.4 Hz, 2H), 7.29e7.59
(200 MHz, CDCl3)
d
1.62 (d, J¼7.0 Hz, 3H), 3.79 (s, 3H), 4.20 (q,
J¼7.0 Hz, 1H), 6.78 (d, J¼8.6 Hz, 2H), 7.22e7.26 (m, 7H). 13C NMR
(m, 8H), 7.93e8.03 (m, 4H). 13C NMR (54.6 MHz, CDCl3)
d 18.9, 38.6,
(54.6 MHz, CDCl3)
136.0, 143.4, 159.6.
d 21.8, 49.1, 55.2, 114.2, 125.1, 127.0, 127.3, 128.3,
62.9, 120.9, 127.7, 128.7, 128.9, 129.4, 131.4, 133.2, 133.4, 133.6, 136.1,
136.9, 194.8, 195.1.
4.4.21. (E)-1-Methoxy-4-(3-p-tolylallyl)benzene (14a).36 1H NMR
(400 MHz, CDCl3)
d
2.34 (s, 3H), 3.50 (d, J¼6.6 Hz, 2H), 3.80 (s, 3H),
4.4.31. (E)-4-Hydroxy-3-(4-phenylbut-3-en-2-yl)-2H-chromen-2-
one (14k).3i 1H NMR (200 MHz, CDCl3)
d
1.51 (d, J¼7.0 Hz, 3H),
6.22e6.29 (m, 1H), 6.40 (d, J¼15.6 Hz, 1H), 6.86 (d, J¼8.6 Hz, 2H),
7.10e7.20 (m, 4H), 7.29 (d, J¼8.2 Hz, 2H).13C NMR (100 MHz, CDCl3)
4.17e4.22 (m, 1H), 6.61e6.71 (m, 1H), 6.78 (d, J¼16.0 Hz, 1H),
7.19e7.55 (m, 8H), 7.77 (d, J¼7.8 Hz, 1H). 13C NMR (54.6 MHz, CDCl3)
d
21.1, 38.4, 55.2,113.8,125.9,128.6,129.1,129.5,130.5,132.1,134.5,
136.9, 158.7.
d
16.5, 32.7, 107.7, 116.0, 116.4, 122.9, 123.9, 126.4, 128.1, 128.7, 131.6,
131.7, 131.9, 135.9, 152.5, 160.7, 163.3.
4.4.22. 1-Cinnamyl-4-methoxybenzene (14b).36 1H NMR (200 MHz,
CDCl3):
d
3.49(d, J¼5.8Hz,2H), 3.79(s, 3H), 6.34e6.41(m, 2H),6.86(d,
4.4.32. (E)-(3-Ethoxyprop-1-enyl)benzene
(14l).38 1H
NMR
J¼8.6 Hz, 2H), 7.15e7.39 (m, 7H). 13C NMR (54.6 MHz, CDCl3)
d 38.5,
(200 MHz, CDCl3)
(d, J¼6.0 Hz, 2H), 6.33 (dt, J¼6.0 and 15.9 Hz,1H), 6.60 (d, J¼15.9 Hz,
1H), 7.15e7.50 (m, 5H).
d
1.33 (t, J¼7.0 Hz, 3H), 3.59 (q, J¼7.0 Hz, 2H), 4.15
55.3, 113.9, 126.1, 127.1, 128.5, 129.6, 129.7, 130.7, 132.2, 137.6, 158.6.
4.4.23. (E)-1-Chloro-4-(3-(4-methoxyphenyl)prop-1-enyl)benzene
(14c).36 1H NMR (400 MHz, CDCl3)
d
3.48 (d, J¼6.0 Hz, 2H), 3.79 (s,
4.4.33. (E)-(3-tert-Butoxyprop-1-enyl)benzene (14m).38 1H NMR
3H), 6.28e6.39 (m, 1H), 6.43 (d, J¼15.6 Hz, 1H), 6.90 (d, J¼8.6 Hz,
(200 MHz, CDCl3)
J¼5.3 and 15.8 Hz, 1H), 6.60 (d, J¼15.8 Hz, 1H), 7.15e7.40 (m, 5H).
d
1.22 (s, 9H), 4.05 (d, J¼5.3 Hz, 2H), 6.20 (dt,
2H), 7.20 (d, J¼8.6 Hz, 2H), 7.24e7.40 (m, 4H). 13C NMR (100 MHz,
CDCl3)
d 38.3, 55.2, 113.8, 127.3, 128.7, 129.2, 129.7, 130.2, 131.8,
132.4, 136.0, 158.2.
4.4.34. N-Cinnamyl-4-methylbenzenesulfonamide (14n).3i 1H NMR
(CDCl3, 400 MHz)
d
2.41 (s, 3H), 3.75 (t, J¼6.4 Hz, 2H), 4.63e4.64 (m,
4.4.24. (E)-1-Bromo-4-(3-(4-methoxyphenyl)prop-1-enyl)benzene
1H), 5.97e6.04 (m, 1H), 6.43 (d, J¼16.0 Hz, 1H), 7.23e7.31 (m, 7H),
(14d).36 1H NMR (400 MHz, CDCl3)
d
3.49 (d, J¼4.9 Hz, 2H), 3.81 (s,
7.78 (d, J¼8.0 Hz, 2H). 13C NMR (CDCl3, 100 MHz)
d 21.4, 45.4, 124.0,
3H), 6.30e6.37 (m, 2H), 6.87 (d, J¼8.8 Hz, 2H), 7.15 (d, J¼8.8 Hz, 2H),
126.4, 127.1, 127.8, 128.5, 129.7, 133.0, 136.0, 137.1, 143.5.
7.28 (d, J¼8.6Hz, 2H), 7.46(d, J¼8.6Hz,2H).13CNMR(100MHz,CDCl3)
d
38.4, 55.2, 113.9, 120.7, 127.4, 129.4, 130.5, 131.3, 131.8, 136.5, 157.9.
4.4.35. N-Cinnamyl-4-methyl-N-phenylbenzenesulfonamide (14o).3i
1H NMR (200 MHz, CDCl3)
d
2.45 (s, 3H), 4.36 (d, J¼6.4 Hz, 2H),
4.4.25. 2-Cinnamylthiophene (14e).3i 1H NMR (200 MHz, CDCl3)
d (2-
6.05e6.19 (m, 1H), 6.40 (d, J¼16.0 Hz, 1H), 7.08e7.36 (m, 12H), 7.55
cinnamylthiophene) 3.74 (d, J¼6.4 Hz, 2H), 6.29e6.56 (m, 2H),
6.86e6.88 (m, 1H), 6.93e6.97 (m, 1H), 7.15e7.39 (m, 5H). (3-
Cinnamylthiophene) 3.56 (d, J¼5.8 Hz, 2H), 6.29e6.56 (m, 2H),
(d, J¼8.4 Hz, 2H). 13C NMR (54.6 MHz, CDCl3)
d 21.5, 53.3, 124.1,
126.4, 127.8, 128.5, 128.9, 129.4, 133.7, 135.7, 136.3, 139.3, 143.4.
6.97e7.02(m, 2H), 7.15e7.39(m, 5H).13C NMR (54.6 MHz, CDCl3):
d (2-
4.4.36. N-Cinnamyl-N-phenylmethanesulfonamide (14p).3i 1H NMR
and 3-cinnamylthiophene) 33.4, 33.8, 120.8, 123.7, 124.7, 125.6, 126.1,
126.2, 126.9, 127.1, 127.3, 128.2, 128.3, 128.5, 131.1, 131.4, 137.2, 140.5,
143.1.
(200 MHz, CDCl3)
(dd, J¼6.6 and 15.8 Hz, 1H), 6.49 (d, J¼15.8 Hz, 1H), 7.24e7.40 (m,
10H). 13C NMR (54.6 MHz, CDCl3):
38.3, 53.4, 123.9, 126.4, 127.9,
128.0, 128.5, 129.4, 134.1, 136.1, 139.3.
d
2.96 (s, 3H), 4.46 (d, J¼6.6 Hz, 2H), 6.15e6.29
d
4.4.26. 2-Cinnamyl-5-methylfuran (14f).3i 1H NMR (200 MHz,
CDCl3)
d
2.29 (s, 3H), 3.53 (d, J¼6.4 Hz, 2H), 5.91e597 (m, 2H),
4.4.37. tert-Butyl(cinnamyl)sulfane (14q).7q 1H NMR (200 MHz,
CDCl3)
1.22 (s, 9H), 3.67 (d, J¼5.1 Hz, 2H), 6.48 (dt, J¼5.2 and
15.9 Hz, 1H), 6.66 (d, J¼15.9 Hz, 1H), 7.15e7.44 (m, 5H).
6.23e6.39 (m, 1H), 6.52 (d, J¼15.8 Hz, 1H), 7.19e7.42 (m, 5H). 13
C
d
NMR (54.6 MHz, CDCl3)
128.5, 131.7, 137.4, 150.9, 152.0.
d 13.5, 31.9, 106.1, 106.3, 126.1, 126.2, 127.2,
4.4.27. 2-Cinnamyl-1,3-diphenylpropane-1,3-dione (14g).37 1H NMR
4.4.38. Cinnamyl(4-methoxyphenyl)sulfane
(14r).7q 1H
NMR
(400 MHz, CDCl3)
d
3.09 (t, J¼6.6 Hz, 2H), 5.50 (t, J¼6.6 Hz, 1H),
(200 MHz, CDCl3) 3.58 (d, J¼6.0 Hz, 2H), 3.78 (s, 3H), 6.21e6.25
(m, 2H), 6.82 (d, J¼8.6 Hz, 2H), 7.21e7.30 (m, 5H), 7.37 (d, J¼8.6 Hz,
2H). 13C NMR (54.6 MHz, CDCl3)
39.3, 55.3, 114.5, 125.6, 125.7,
d
6.22e6.35 (m, 1H), 6.52 (d, J¼15.8 Hz, 1H), 7.22e7.36 (m, 5H),
7.43e7.55 (m, 4H), 7.60e7.68 (m, 2H), 8.03 (d, J¼7.8 Hz, 4H). 13C
d
NMR (100 MHz, CDCl3)
d
32.6, 56.8, 125.8, 126.4, 127.1, 128.2, 128.5,
126.3, 127.5, 128.5, 132.5, 134.4, 136.9, 159.3.
128.7, 132.3, 133.4, 135.7, 136.9, 195.6.
4.4.39. 2-(But-2-enyl)-1,4-dimethylbenzene (14s).3a (Mixture of E
4.4.28. 3-Cinnamylpentane-2,4-dione (14h).37 1H NMR (400 MHz,
and Z isomers) 1H NMR (200 MHz, CDCl3)
d
1.67e1.71 (m, 3H), 2.26
(s, 3H), 2.31 (s, 3H), 3.27 (d, J¼5.5 Hz, 2H), 5.47e5.54 (m, 2H),
6.96e7.06 (m, 3H). 13C NMR (54.6 MHz, CDCl3)
12.8,17.8,18.8,18.9,
CDCl3)
d
2.13 (s, 3H), 2.22 (s, 3H), 2.74 (t, J¼7.2 Hz, 1H), 3.16 (d,
J¼4.8 Hz, 1H), 6.00e6.50 (m, 2H), 7.21e7.38 (m, 5H). 13C NMR
d

954
A.K. Maity et al. / Tetrahedron 69 (2013) 942e956
20.9, 29.7, 31.0. 36.5, 124.5, 125.2, 126.0, 126.7, 128.6, 129.3, 129.4,
129.7, 130.0, 133.0, 135.3, 138.9.
60.4, 60.6, 80.6, 98.1, 106.0, 120.9, 124.2, 127.4, 128.1, 131.4, 131.7,
142.8, 152.7, 152.8.
4.4.40. (E)-1-(But-2-enyl)-4-methoxybenzene (14t).39 1H NMR
4.4.49. 1,3,5-Trimethoxy-2-(4-phenylbut-3-yn-2-yl)benzene
(200 MHz, CDCl3)
d
1.68 (d, J¼6.0 Hz, 3H), 3.26 (d, J¼6.0 Hz, 2H),
(15g).3g 1H NMR (400 MHz, CDCl3)
d
1.51 (d, J¼7.2 Hz, 3H), 3.81 (s,
3H), 3.84 (s, 6H), 4.54 (q, J¼7.2 Hz, 1H), 6.16 (s, 2H), 7.21e7.24 (m,
3H), 7.36e7.38 (m, 2H). 13C NMR (100 MHz, CDCl3)
20.3, 21.0, 55.3,
55.9, 78.1, 91.3, 94.4, 112.1, 124.7, 126.9, 128.0, 131.5, 158.6, 159.8.
3.79 (s, 3H), 5.44e5.64 (m, 2H), 6.83 (d, J¼8.8 Hz, 2H), 7.10 (d,
J¼8.8 Hz, 2H). 13C NMR (54.6 MHz, CDCl3)
d
17.8, 38.1, 55.2, 113.7,
d
125.9, 129.3, 130.4, 133.1, 157.8.
4.4.41. 2-(But-2-enyl)-1,3,5-trimethoxy benzene (14u).40 1H NMR
(400 MHz, CDCl3)
J¼6.0 Hz, 2H), 3.83 (s, 9H), 5.40e5.52 (m,1H), 5.55e6.62 (m,1H), 6.18
(s, 2H). (Z isomer) 1.80 (d, J¼5.5 Hz, 3H), 3.39 (d, J¼5.5 Hz, 2H), 3.82
(s, 9H), 5.40e5.51 (m, 1H), 5.56e5.63 (m, 1H), 6.18 (s, 2H). 13C NMR
4.4.50. 4-(4-Phenylbut-3-yn-2-yl)phenol
(15h).42 1H
NMR
d
(E isomer) 1.65 (d, J¼6.4 Hz, 3H), 3.29 (d,
(200 MHz, CDCl3)
d
1.46 (d, J¼7.2 Hz, 3H), 3.98 (q, J¼7.2 Hz,1H), 6.88
(d, J¼8.0 Hz, 2H), 7.14 (d, J¼8.0 Hz, 2H), 7.20e7.42 (m, 5H). 13C NMR
(54.6 MHz, CDCl3)
129.1, 132.2, 153.4.
d 22.5, 27.6, 82.1, 91.9, 115.5, 122.2, 128.3, 128.5,
(100 MHz, CDCl3) d (E and Z isomers) 12.6,17.7, 20.6, 25.6, 55.2, 55.6,
55.8, 90.6, 109.9, 110.2, 123.0, 124.1, 129.4, 129.6, 158.5, 159.2.
4.4.51. 2-(2-Methyl-4-phenylbut-3-yn-2-yl)furan (15i).3g 1H NMR
(400 MHz, CDCl3)
1.66 (s, 6H), 6.23 (d, J¼3.2 Hz, 1H), 6.31 (dd,
J¼2.0 and 3.2 Hz, 1H), 7.27e7.28 (m, 3H), 7.36 (d, J¼2.0 Hz, 2H),
7.40e7.44 (m, 2H). 13C NMR (100 MHz, CDCl3)
29.0, 32.6, 80.7, 94.1,
d
4.4.42. 2-(Hex-2-enyl)-1,4-dimethylbenzene (14v).3a (Mixture of E
and Z isomers) 1H NMR (200 MHz, CDCl3)
d
0.90 (t, J¼7.0 Hz, 3H),
d
1.28e1.48 (m, 2H), 1.95e2.05 (m, 2H), 2.25 (s, 3H), 2.31 (s, 3H), 3.28
103.7, 109.9, 123.4, 127.7, 128.1, 131.6, 141.4, 158.9.
(d, J¼5.3 Hz, 2H), 5.46e5.53 (m, 2H), 6.92e7.06 (m, 3H). 13C NMR
(54.6 MHz, CDCl3)
d
13.4, 18.5, 20.6, 22.3, 34.3, 36.3, 126.4, 127.8,
4.4.52. 2-Methyl-5-(2-methyl-4-phenylbut-3-yn-2-yl)thiophene
129.4, 129.6, 131.2, 132.7, 135.0, 138.6.
(15j).43 1H NMR (400 MHz, CDCl3)
d 1.70 (s, 6H), 2.44 (s, 3H), 6.58
(d, J¼3.2 Hz, 1H), 6.81 (d, J¼3.2 Hz, 1H), 7.26e7.48 (m, 5H). 13C NMR
4.4.43. 1-Methoxy-4-(2-methyl-4-p-tolylbut-3-yn-2-yl)benzene
(100 MHz, CDCl3) d 15.3, 32.6, 34.3, 81.2, 95.8, 122.2, 123.7, 124.4,
(15a).3g 1H NMR (200 MHz, CDCl3)
d
1.65 (s, 6H), 2.34 (s, 3H), 3.81
127.7, 128.1, 131.5, 137.8, 150.3.
(s, 3H), 6.87 (dd, J¼2.2 and 8.8 Hz, 2H), 7.10 (d, J¼7.8 Hz, 2H), 7.34 (d,
J¼7.8 Hz, 2H), 7.53 (dd, J¼2.2 and 8.8 Hz, 2H). 13C NMR (54.6 MHz,
4.4.53. 2-(2-Methyl-4-phenylbut-3-yn-2-yl)thiophene
(15k). 1H
CDCl3)
d
21.4, 31.9, 35.7, 55.2, 81.8, 96.0, 113.5, 120.8, 126.6, 128.9,
NMR (200 MHz, CDCl3)
(m,1H), 7.16e7.19 (m,1H), 7.22e7.36 (m, 3H), 7.42e7.47 (m, 2H); 13
NMR (54.6 MHz, CDCl3) 32.8, 81.3, 95.7, 122.7, 123.4, 123.5, 126.5,
d 1.75 (s, 6H), 6.92e6.97 (m, 1H), 7.06e7.08
131.4, 137.5, 139.4, 158.1.
C
d
4.4.44. 1-Methoxy-4-(2-methyl-4-phenylbut-3-yn-2-yl)benzene
127.8, 128.2, 131.6, 152.8. Anal. Calcd for C15H14S (226.08): C, 79.60;
H, 6.23. Found: C, 79.76; H, 6.51.
(15b).3g 1H NMR (400 MHz, CDCl3)
d 1.66 (s, 6H), 3.81 (s, 3H), 6.88
(dd, J¼2.0 and 8.8 Hz, 2H), 7.29e7.33 (m, 3H), 7.45 (d, J¼7.2 Hz, 2H),
7.54 (dd, J¼2.0 and 8.8 Hz, 2H).13C NMR (100 MHz, CDCl3)
d
31.8, 35.7,
4.4.54. 2-(2-Methyl-4-phenylbut-3-yn-2-yl)benzofuran (15l).3g 1H
55.2, 81.8, 96.7, 113.5, 123.8, 126.6, 127.6, 128.1, 131.5, 139.2, 158.0.
NMR (400 MHz, CDCl3)
d
1.76 (s, 6H), 6.66 (s, 1H), 7.18e7.30 (m, 6H),
28.8, 33.0, 81.2,
7.43e7.51 (m, 3H). 13C NMR (100 MHz, CDCl3)
d
4.4.45. 1-Chloro-4-(3-(4-methoxyphenyl)-3-methylbut-1-ynyl)ben-
93.4, 100.8, 111.0, 120.6, 122.5, 123.2, 123.5, 127.8, 128.1, 128.5, 131.6,
154.8, 162.0.
zene (15c).3g 1H NMR (200 MHz, CDCl3)
d 1.68 (s, 6H), 3.85 (s, 3H),
6.92 (dd, J¼2.2 and 9.0 Hz, 2H), 7.27e7.33 (m, 2H), 7.37e7.42 (m,
2H), 7.56 (dd, J¼2.2 and 9.0 Hz, 2H). 13C NMR (54.6 MHz, CDCl3)
4.4.55. (3-Methylhex-5-en-1-ynyl)benzene
(15m).42 1H
NMR
d
31.7, 35.7, 55.3, 80.7, 97.9, 113.6, 122.4, 126.6, 128.5, 132.8, 133.6,
(400 MHz, CDCl3)
d
1.31 (d, J¼7.2 Hz, 3H), 2.27e2.44 (m, 2H),
138.9, 158.1.
2.72e2.84 (m, 1H), 5.11e5.20 (m, 2H), 5.92e6.06 (m, 1H), 7.26e7.46
(m, 5H). 13C NMR (100 MHz, CDCl3)
124.1, 127.5, 128.1, 131.6, 136.0.
d 20.5, 26.4, 41.1, 82.1, 94.0,116.1,
4.4.46. 1-Bromo-4-(3-(4-methoxyphenyl)-3-methylbut-1-ynyl)ben-
zene (15d).41 1H NMR (200 MHz, CDCl3)
d 1.62 (s, 6H), 3.82 (s, 3H),
6.96 (dd, J¼2.2 and 9.0 Hz, 2H), 7.26e7.36 (m, 2H), 7.39e7.44 (m, 2H),
4.4.56. 3-(2-Methyl-4-phenylbut-3-yn-2-yl)pentane-2,4-dione
(15n).44 1H NMR (400 MHz, CDCl3)
1.59 (s, 6H), 2.18 (s, 6H), 4.22
(s, 1H), 7.23e7.43 (m, 5H). 13C NMR (100 MHz, CDCl3)
28.6, 30.1,
7.52 (dd, J¼2.2 and 9.0 Hz, 2H).13C NMR (54.6MHz, CDCl3)
d
31.4, 35.8,
d
55.2, 80.4, 97.8, 113.5, 122.9, 126.7, 128.8, 132.9, 133.5, 138.5, 158.2.
d
31.1, 35.2, 42.2, 83.7, 91.6, 122.8, 128.1, 128.2, 131.6, 203.6.
4.4.47. 1-Methoxy-4-(4-p-tolylbut-3-yn-2-yl)benzene (15e).3g (para
Isomer) 1H NMR (200 MHz, CDCl3)
d
1.55 (d, J¼7.0 Hz, 3H), 2.34 (s,
4.4.57. (3-Ethoxy-3-methylbut-1-ynyl)benzene (15o).3g 1H NMR
3H), 3.80 (s, 3H), 3.93 (q, J¼7.0 Hz, 1H), 6.88 (d, J¼8.0 Hz, 2H), 7.10
(400 MHz, CDCl3)
d
1.24 (t, J¼7.2 Hz, 3H), 1.55 (s, 6H), 3.68 (q,
(d, J¼8.0 Hz, 2H), 7.31e7.39 (m, 4H); 13C NMR (54.6 MHz, CDCl3)
J¼7.2 Hz, 2H), 7.29e7.30 (m, 3H), 7.41e7.43 (m, 2H). 13C NMR
d
21.4, 24.6, 31.6, 55.3, 82.2, 92.1, 113.9, 120.7, 127.9, 128.9, 131.5,
(100 MHz, CDCl3)
128.1, 131.6.
d 15.8, 29.3, 59.4, 70.2, 83.7, 91.6, 122.9, 128.0,
135.6, 137.7, 158.3; (ortho isomer) 1H NMR (200 MHz, CDCl3)
(d, J¼7.0 Hz, 3H), 2.33 (s, 3H), 3.85 (s, 3H), 4.38 (q, J¼7.0 Hz, 1H),
6.84e7.67 (m, 8H); 13C NMR (54.6 MHz, CDCl3)
21.4, 23.0, 26.1,
d 1.49
d
4.4.58. (3-(Hex-2-enyloxy)-3-methylbut-1-ynyl)benzene (15p).3g 1H
NMR (400 MHz, CDCl3)
55.4, 81.7, 92.3, 110.4, 120.7, 120.9, 127.7, 127.9, 128.9, 131.5, 131.8,
137.5, 156.0. Anal. Calcd for C18H18O (250.14): C, 86.36; H, 7.25.
Found: C, 86.69; H, 7.46.
d
0.89 (t, J¼7.6 Hz, 3H), 1.37e1.42 (m, 2H),
1.57 (s, 6H), 2.04e2.11 (m, 2H), 4.23 (d, J¼5.6 Hz, 2H), 5.55e5.61 (m,
2H), 7.29e7.31 (m, 3H), 7.41e7.44 (m, 2H). 13C NMR (100 MHz,
CDCl3) 13.6, 22.6, 28.9, 60.1, 65.6, 70.5, 84.1, 91.4, 122.8, 126.7, 128.1,
128.2, 131.6, 133.1.
4.4.48. 1,2,3-Trimethoxy-4-(2-methyl-4-phenylbut-3-yn-2-yl)ben-
zene (15f).3g 1H NMR (400 MHz, CDCl3)
d
1.73 (s, 6H), 3.86 (s, 3H),
3.87 (s, 3H), 3.98 (s, 3H), 6.61 (d, J¼8.8 Hz, 1H), 7.25e7.29 (m, 4H),
7.41e7.44 (m, 2H). 13C NMR (54.6 MHz, CDCl3)
30.1, 34.9, 55.9,
4.4.59. 4-Methyl-N-(2-methyl-4-phenylbut-3-yn-2-yl)benzenesulfo-
d
namide (15q).3g 1H NMR (400 MHz, CDCl3)
d 1.65 (s, 6H), 2.26 (s,

A.K. Maity et al. / Tetrahedron 69 (2013) 942e956
955
3H), 4.68 (s, 1H), 7.05 (d, J¼8.0 Hz, 2H), 7.11 (d, J¼8.0 Hz, 2H),
7.20e7.28 (m, 3H), 7.78 (d, J¼8.0 Hz, 2H). 13C NMR (100 MHz, CDCl3)
temperature program: 80 ꢁCd1 mind5 ꢁC/mind100 ꢁCd20 ꢁC/
mind160 ꢁCd20 min.
d
21.3, 30.9, 50.5, 83.2, 90.4, 122.3, 127.5, 127.8, 128.1, 129.3, 131.5,
Allylation kinetics. GC analysis was performed using a flame
138.4, 143.1.
ionization detector using 30 mꢂ0.25 mmꢂ0.25
mm SS 100% di-
methyl polysiloxane capillary column. n-Decane was used as in-
ternal standard. The analytical conditions are as follows: injector
temperature: 200 ꢁC; detector temperature: 280 ꢁC; career gas (N2)
flow: 1.75 bar; oven temperature program: 55 ꢁCd7 mind5 ꢁC/
mind170 ꢁCd1 mind30 ꢁC/mind275 ꢁCd15 min.
4.4.60. N-(4-(2,6-Dimethylphenyl)-2-methylbut-3-yn-2-yl)-4-
methylbenzenesulfonamide (15r). 1H NMR (200 MHz, CDCl3)
d 1.66
(s, 6H), 2.13 (s, 3H), 2.18 (s, 6H), 5.27 (br,1H), 6.93e7.09 (m, 5H), 7.75
(d, J¼8.2 Hz, 2H). 13C NMR (100 MHz, CDCl3)
d 20.6, 21.1, 31.0, 50.8,
80.9, 98.9, 122.1, 126.3, 127.3, 127.6, 129.0, 138.5, 140.1, 142.9. Anal.
Calcd for C20H23NO2S (341.14): C, 70.35; H, 6.79; N, 4.10. Found: C,
70.48, H, 7.05, N, 4.41.
Propargylation kinetics. GC analysis was performed using a flame
ionization detector using 30 mꢂ0.25 mmꢂ0.25
mm SS 100% di-
methyl polysiloxane capillary column. n-Nonane was used as in-
ternal standard. The analytical conditions are as follows: injector
temperature: 200 ꢁC; detector temperature: 280 ꢁC; career gas (N2)
flow: 1.75 bar; oven temperature program: 60 ꢁCd6 mind5 ꢁC/
mind170 ꢁCd1 mind30 ꢁC/mind275 ꢁCd7 min.
4.4.61. (3-Methyl-1-phenylpent-1-yn-3-yl)(propyl)sulfane (15s).3g 1H
NMR (400 MHz, CDCl3)
d
1.02 (t, J¼7.4 Hz, 3H), 1.13 (t, J¼7.2 Hz, 3H),
1.59 (s, 3H), 1.64e1.72 (m, 2H), 1.74e1.81 (m, 1H), 1.83e1.91 (m, 1H),
2.76 (t, J¼7.2 Hz, 2H), 7.28e7.30 (m, 3H), 7.39e7.42 (m, 2H). 13C NMR
(100 MHz, CDCl3)
d 9.8, 13.8, 22.9, 28.2, 32.2, 35.6, 43.7, 83.4, 92.5,
Acknowledgements
123.3, 127.8, 128.2, 131.6.
We thank DST (financial support to S.R.), UGC (fellowship to
A.K.M.) and CSIR (fellowship to P.N.C.). S.R. thanks Prof. Manish
Bhattacharjee for helpful discussions, support, and encouragement.
4.4.62. 1,4-Bis(3-(4-methoxyphenylthio)-3-methylbut-1-ynyl)ben-
zene (15t). 1H NMR (200 MHz, CDCl3)
d 1.63 (s, 12H), 3.86 (s, 6H),
6.92 (d, J¼8.8 Hz, 4H), 7.28e7.30 (m, 4H), 7.62 (d, J¼8.8 Hz, 4H). 13
C
NMR (54.6 MHz, CDCl3)
d 30.3, 42.7, 55.5, 82.2, 95.9, 114.1, 123.0,
Supplementary data
123.4, 131.4, 138.9, 160.9. Anal. Calcd for C30H30O2S2 (486.17): C,
74.04; H, 6.21. Found: C, 73.79; H, 6.59.
Supplementary data associated with this article can be found in
the online version, at http://dx.doi.org/10.1016/j.tet.2012.10.086.
4.4.63. (3-Methylbut-3-en-1-ynyl)benzene
(16).3g 1H
NMR
(200 MHz, CDCl3)
d
1.99 (s, 3H), 5.30 (d, J¼3.2 Hz, 1H), 5.40 (d,
References and notes
J¼3.2 Hz, 1H), 7.29e7.32 (m, 3H), 7.42e7.47 (m, 2H). 13C NMR
1. Selected recent reviews on multimetallic catalysis: (a) Shibasaki, M.; Kanai, M.;
Matsunaga, S.; Kumagai, N. Acc. Chem. Res. 2009, 42, 1117; (b) Shibasaki, M.;
Yamamoto, Y. Multimetallic Catalysts in Organic Synthesis; Wiley-VCH: Wein-
heim, 2005; (c) Haak, R. M.; Wezenberga, S. J.; Kleij, A. W. Chem. Commun. 2010,
2713.
(54.6 MHz, CDCl3)
131.5.
d 23.5, 88.4, 90.5, 121.9, 123.2, 126.8, 128.1, 128.2,
4.4.64. 1,1-Dimethyl-3-(2,4,6-trimethoxyphenyl)-1H-indene (17a).3g
1H NMR (400 MHz, CDCl3)
1.47 (s, 6H), 3.69 (s, 6H), 3.86 (s, 3H),
2. Selected examples from recent literature: (a) Ooi, T.; Takahashi, M.; Yamada,
M.; Tayama, E.; Omoto, K.; Maruoka, K. J. Am. Chem. Soc. 2004, 126, 1150; (b)
Nishibayashi, Y.; Wakiji, I.; Hidai, M. J. Am. Chem. Soc. 2000, 122, 11019; (c)
Sammis, G. M.; Danjo, H.; Jacobsen, E. N. J. Am. Chem. Soc. 2004, 126, 9928; (d)
Sasai, H.; Arai, T.; Satow, Y.; Houk, K. N.; Shibasaki, M. J. Am. Chem. Soc. 1995, 117,
6194; (e) Yabu, K.; Masumoto, S.; Yamasaki, S.; Hamashima, Y.; Kanai, M.; Du,
W.; Curran, D. P.; Shibasaki, M. J. Am. Chem. Soc. 2001, 123, 9908; (f) Noyori, R.;
Kitamura, M. Angew. Chem., Int. Ed. Engl. 1991, 30, 49; (g) Weber, M.; Jautze, S.;
Frey, W.; Peters, R. J. Am. Chem. Soc. 2010, 132, 12222; (h) Trost, B. M.; Ito, H. J.
Am. Chem. Soc. 2000, 122, 12003; (i) Schneider, C. Angew. Chem., Int. Ed. 2009,
48, 2082; (j) Onodera, G.; Imajima, H.; Yamanashi, M.; Nishibayashi, Y.; Hidai,
M.; Uemura, S. Organometallics 2004, 23, 5841; (k) Miyazaki, T.; Tanabe, Y.;
Yuki, M.; Miyake, Y.; Nishibayashi, Y. Organometallics 2011, 30, 3194.
3. For our group’s publications on heterobimetallic catalysis, see: (a) Choudhury,
J.; Podder, S.; Roy, S. J. Am. Chem. Soc. 2005, 127, 6162; (b) Podder, S.; Choudhury,
J.; Roy, S. J. Org. Chem. 2007, 72, 3129; (c) Podder, S.; Choudhury, J.; Roy, U. K.;
Roy, S. J. Org. Chem. 2007, 72, 3100; (d) Podder, S.; Roy, S. Tetrahedron 2007, 63,
9146; (e) Choudhury, J.; Roy, S. J. Mol. Catal. A Chem. 2008, 279, 37; (f) Roy, S.;
Podder, S.; Choudhury, J. J. Chem. Sci. 2008, 120, 429; (g) Chatterjee, P. N.; Roy, S.
J. Org. Chem. 2010, 75, 4413; (h) Chatterjee, P. N.; Roy, S. Tetrahedron 2011, 67,
4569; (i) Chatterjee, P. N.; Roy, S. Tetrahedron 2012, 68, 3776.
d
6.22 (s, 2H), 6.29 (s,1H), 6.93 (d, J¼4.4 Hz,1H), 7.16 (d, J¼4.8 Hz, 2H),
7.34 (d, J¼4.4 Hz, 1H). 13C NMR (100 MHz, CDCl3)
d 24.7, 48.6, 55.2,
55.9, 91.1, 106.2, 120.7, 120.8, 124.3, 125.9, 132.4, 143.9, 146.6, 153.1,
159.1, 160.6.
4.4.65. 1,1,5-Trimethyl-3-(2,4,6-trimethoxyphenyl)-1H-indene
(17b).3g 1H NMR (400 MHz, CDCl3)
d 1.40 (s, 6H), 2.39 (s, 3H), 3.69
(s, 6H), 3.86 (s, 3H), 6.22 (s, 3H), 6.82 (d, J¼7.6 Hz, 1H), 6.98 (d,
J¼7.6 Hz, 1H), 7.17 (s, 1H). 13C NMR (100 MHz, CDCl3)
d 21.5, 24.9,
48.5, 55.3, 55.9, 91.2, 106.5, 120.5, 121.8, 126.7, 132.3, 134.1, 141.4,
145.8, 153.4, 159.2, 160.6.
4.5. General procedure for the Hammett correlation study
A 10-mL Schlenk flask equipped with a magnetic bar, was
charged with catalyst 2 (2.6 mg, 0.0025 mmol), arene (4e5 mmol),
DCE (1.5 mL), and internal standard for GC. The flask was degassed
with argon and placed into a constant temperature bath. After the
mixture was stirred vigorously for 5 min, the corresponding alcohol
(0.25 mmol) was added to it, and the reaction was allowed to
continue at the specific temperature. Known volume of aliquot was
withdrawn periodically, filtered through a short pad of Celite, di-
luted with dichloroethane, and the organic layer was analyzed with
GC against n-nonane/n-decane as internal standard.
4. Maity, A. K.; Roy, S. J. Org. Chem. 2012, 77, 2935.
5. For recent reviews on alcohol activation, see: (a) Bandini, M.; Tragni, M. Org.
Biomol. Chem. 2009, 7, 1501; (b) Biannic, B.; Aponick, A. Eur. J. Org. Chem. 2011,
6605; (c) Emer, E.; Sinisi, R.; Capdevila, M. G.; Petruzziello, D.; Vincentiis, F. D.;
Cozzi, P. G. Eur. J. Org. Chem. 2011, 647; (d) Ljungdahl, N.; Kann, N. Angew. Chem.,
Int. Ed. 2009, 48, 642; (e) Muzart, J. Tetrahedron 2008, 64, 5815; (f) Muzart, J.
Tetrahedron 2005, 61, 4179; (g) Muzart, J. Eur. J. Org. Chem. 2007, 3077; (h)
Tamaru, Y. Eur. J. Org. Chem. 2005, 2647.
6. Selected examples from recent literature for benzyl alcohol activation: (a) Noji,
M.; Ohno, T.; Fuji, K.; Futaba, N.; Tajima, H.; Ishii, K. J. Org. Chem. 2003, 68, 9340;
(b) Rueping, M.; Nachtsheim, B. J.; Kuenkel, A. Org. Lett. 2007, 9, 825; (c) Han, X.;
Wu, J. Org. Lett. 2010, 12, 5780; (d) Rubin, M.; Gevorgyan, V. Org. Lett. 2001, 3,
2705; (e) Yasuda, M.; Saito, T.; Ueba, M.; Baba, A. Angew. Chem., Int. Ed. 2004, 43,
1414; (f) Iovel, I.; Mertins, K.; Kischel, J.; Zapf, A.; Beller, M. Angew. Chem., Int. Ed.
2005, 44, 3913; (g) Yasuda, M.; Somyo, T.; Baba, A. Angew. Chem., Int. Ed. 2006,
45, 793; (h) Sharma, G. V. M.; Reddy, K. L.; Lakshmi, P. S.; Ravi, R.; Kunwar, A. C.
J. Org. Chem. 2006, 71, 3967; (i) Liu, P. N.; Zhou, Z. Y.; Lau, C. P. Chem.dEur. J.
2007, 13, 8610; (j) Yadav, J. S.; Bhunia, D. C.; Krishna, K. V.; Srihari, P. Tetrahedron
Lett. 2007, 48, 8306; (k) Thirupathi, P.; Kim, S. S. Tetrahedron 2010, 66, 2995.
7. Selected examples from recent literature for allyl alcohol activation: (a) Bras, J.
L.; Muzart, J. Tetrahedron 2007, 63, 7942; (b) Yadav, J. S.; Reddy, B. V. S.;
4.5.1. General note on gas chromatography analysis. Benzylation ki-
netics. GC analysis was performed using a flame ionization detector
using 6 ftꢂ1/8 inchꢂ2 mm SS 10% Silicone OV-1 packed column
(from Chrompack). n-Nonane was used as internal standard. The
analytical conditions are as follows: injector temperature: 130 ꢁC;
detector temperature: 240 ꢁC; career gas (N2) flow: 1.9 bar; oven

956
A.K. Maity et al. / Tetrahedron 69 (2013) 942e956
Pandurangam, T.; Rao, K. V. R.; Praneeth, K.; Kumar, G. G. K. S. N.; Madavi, C.;
12. Vogel, A. I.; Tatchell, A. R.; Furniss, B. S.; Hannaford, A. J.; Smith, P. W. G. Vogel’s
Textbook of Practical Organic Chemistry, 5th ed.; Longman Scientific & Technical:
England, 1989.
13. Choudhury, J. Ph.D. Thesis: Designing Cooperative Catalysts within IridiumeTin
Regime: Synthetic and Mechanistic Studies towards Aromatic Alkylation, In-
dian Institute of Technology, Kharagpur, India, 2006.
Kunwar, A. C. Tetrahedron Lett. 2008, 49, 4296; (c) Yadav, J. S.; Reddy, B. V. S.;
Aravind, S.; Kumar, G. G. K. S. N.; Reddy, A. S. Tetrahedron Lett. 2007, 48, 6117; (d)
Huang, W.; Wang, J.; Shen, Q.; Zhou, X. Tetrahedron Lett. 2007, 48, 3969; (e) Qin,
H.; Yamagiwa, N.; Matsunaga, S.; Shibasaki, M. Angew. Chem., Int. Ed. 2007, 46,
409; (f) Guo, S.; Song, F.; Liu, Y. Synlett 2007, 964; (g) Rao, W.; Chan, P. W. H. Org.
Biomol. Chem. 2008, 6, 2426; (h) Bandini, M.; Eichholzer, A.; Kotrusz, P.; Tragni,
M.; Troisi, S.; Umani-Ronchi, A. Adv. Synth. Catal. 2009, 351, 319; (i) Mukherjee,
P.; Widenhoefer, R. A. Org. Lett. 2010, 12, 1184; (j) Ozawa, F.; Okamoto, H.; Ka-
wagishi, S.; Yamamoto, S.; Minami, T.; Yoshifuji, M. J. Am. Chem. Soc. 2002, 124,
10968; (k) Manabe, K.; Kobayashi, S. Org. Lett. 2003, 5, 3241; (l) Kayaki, Y.; Koda,
T.; Ikariya, T. J. Org. Chem. 2004, 69, 2595; (m) Usui, I.; Schmidt, S.; Keller, M.;
Breit, B. Org. Lett. 2008, 10, 1207; (n) Jana, U.; Maiti, S.; Biswas, S. Tetrahedron
Lett. 2007, 48, 7160; (o) Tao, Y.; Zhou, Y.; Qu, J.; Hidai, M. Tetrahedron Lett. 2010,
51, 1982; (p) Utsunomiya, M.; Miyamoto, Y.; Ipposhi, J.; Ohshima, T.; Mashima,
K. Org. Lett. 2007, 9, 3371; (q) Zaitsev, A. B.; Caldwell, H. F.; Pregosin, P. S.; Veiros,
L. F. Chem.dEur. J. 2009, 15, 6468; (r) Zhang, X.; Rao, W.; Chan, S.; Chan, P. W. H.
Org. Biomol. Chem. 2009, 7, 4186; (s) Kothandaraman, P.; Rao, W.; Zhang, X.;
Chan, P. W. H. Tetrahedron 2009, 65, 1833; (t) Zhang, X.; Rao, W.; Chan, P. W. H.
Synlett 2008, 2204.
14. Kawahara, R.; Fujita, K.-I.; Yamaguchi, R. J. Am. Chem. Soc. 2012, 134, 3643.
15. Chatterjee, P. N. Ph.D. Thesis: CarboneCarbon and CarboneHeteroatom Bond
Formation from pi-Activated Alcohol using an IridiumeTin Heterobimetallic
Catalyst, Indian Institute of Technology, Kharagpur, India, 2011.
16. Fischer, D. F.; Barakat, A.; Xin, Z.-Q.; Weiss, M. E.; Peters, R. Chem.dEur. J. 2009,
15, 8722.
ꢁ
17. Rueping, M.; Sunden, H.; Hubener, L.; Sugiono, E. Chem. Commun. 2012, 2201.
18. Titu, D.; Chadha, A. Tetrahedron: Asymmetry 2008, 19, 1698.
19. Lo, C.-N.; Hsu, C.-S. J. Polym. Sci., Part A: Polym. Chem. 2011, 49, 3355.
20. Panteleev, J.; Huang, R. Y.; Lui, E. K. J.; Lautens, M. Org. Lett. 2011, 13, 5314.
21. Mori, H.; Matsuo, T.; Yoshioka, Y.; Katsumura, S. J. Org. Chem. 2006, 71, 9004.
€
22. Schafer, G.; Bode, J. W. Angew. Chem., Int. Ed. 2011, 50, 10913.
23. Wang, F.; Ueda, W. Chem.dEur. J. 2009, 15, 742.
24. Tsuchimoto, T.; Tobita, K.; Hiyama, T.; Fukuzawa, S.-I. J. Org. Chem. 1997, 62,
8. Selected examples from recent literature for propargyl alcohol activation: (a)
Ohri, R. V.; Radosevich, A. T.; Hrovat, K. J.; Huang, M. D.; Holman, T. R.; Toste, F.
D. Org. Lett. 2005, 7, 2501; (b) Hui, H.; Zhao, Q.; Yang, M.; She, D.; Chen, M.;
Huang, G. Synthesis 2008, 191; (c) Yadav, J. S.; Reddy, B. V. S.; Rao, T. S.; Rao, K.
V. R. Tetrahedron Lett. 2008, 49, 614; (d) Georgy, M.; Boucard, V.; Debleds, O.;
Zotto, C. D.; Campagne, J. M. Tetrahedron 2009, 65, 1758; (e) Zhan, Z.; Yu, J.; Liu,
H.; Cui, Y.; Yang, R.; Yang, W.; Li, J. J. Org. Chem. 2006, 71, 8298; (f) Zhan, Z. P.;
Yang, W. Z.; Yang, R. F.; Yu, J. L.; Li, J. P.; Liu, H. J. Chem. Commun. 2006, 3352; (g)
Sanz, R.; Martinez, A.; Alvarez-Gutierrez, J. M.; Rodríguez, F. Eur. J. Org. Chem.
2006, 1383; (h) Yoshimatsu, M.; Otani, T.; Matsuda, S.; Yamamoto, T.; Sawa, A.
Org. Lett. 2008, 10, 4251; (i) Zhang, X.; Teo, W. T.; Chan, P. W. H. Org. Lett. 2009,
11, 4990; (j) Zhang, M.; Yang, H.; Cheng, Y.; Zhu, Y.; Zhu, C. Tetrahedron Lett.
2010, 51, 1176; (k) Mothe, S. R.; Lauw, S. J. L.; Kothandaraman, P.; Chan, P. W. H. J.
Org. Chem. 2012, 77, 6937; (l) Mothe, S. R.; Kothandaraman, P.; Rao, W.; Chan, P.
W. H. J. Org. Chem. 2011, 76, 2521; (m) Mothe, S. R.; Kothandaraman, P.; Lauw, S.
J. L.; Chin, S. M. W.; Chan, P. W. H. Chem.dEur. J. 2012, 18, 6133; (n) Zhang, X.;
Teo, W. T.; Chan, P. W. H. J. Organomet. Chem. 2011, 696, 331.
9. Some Lewis and Brønsted acid-catalyzed rearrangement of cyclopropyl-
carbinols were was reported in recent literature and we are not including
those reports and related discussions here. For instance, see: (a) Hardouin, C.;
Taran, F.; Doris, E. J. Org. Chem. 2001, 66, 4450; (b) Mothe, S. R.; Chan, P. W. H. J.
Org. Chem. 2009, 74, 5887; (c) Rao, W.; Chan, P. W. H. Chem.dEur. J. 2008, 14,
10486; (d) Kothandaraman, P.; Huang, C.; Susanti, D.; Rao, W.; Chan, P. W. H.
Chem.dEur. J. 2011, 17, 10081.
6997.
25. Kaneko, M.; Hayashi, R.; Cook, G. R. Tetrahedron Lett. 2007, 48, 7085.
26. Wang, T.-W.; Intaranukulkit, T.; Rosana, M. R.; Slegeris, R.; Simon, J.; Dudley, G.
B. Org. Biomol. Chem. 2012, 10, 248.
27. Xia, Q.; Chen, W.; Qiu, H. J. Org. Chem. 2011, 76, 7577.
28. Ruiping, M.; Bootwicha, T.; Sugiono, E. Adv. Synth. Catal. 2010, 352, 2961.
29. Hall, S. S.; Farahat, S. E. J. Heterocycl. Chem. 1987, 24, 1205.
30. Goldoni, L.; Cravotto, G.; Penoni, A.; Tollari, S.; Palmisano, G. Synlett 2005, 927.
31. Horn, M.; Mayr, H.; Lacote, E.; Merling, E.; Deaner, J.; Wells, S.; McFadden, T.;
Curran, D. P. Org. Lett. 2012, 14, 82.
32. Yu, X.; Liu, C.; Jiang, L.; Xu, Q. Org. Lett. 2011, 13, 6184.
33. Das, R. N.; Sarma, K.; Pathak, M. G.; Goswami, A. Synlett 2010, 2908.
34. Paulussen, H.; Ottenbourgs, B.; Vanderzande, D.; Adriaensens, P.; Gelen, J.
Polymer 1997, 38, 5221.
35. Martin, M. T.; Thomas, A. M.; York, D. G. Tetrahedron Lett. 2002, 43, 2145.
36. Rao, M. L. N.; Banerjee, D.; Giri, S. J. Organomet. Chem. 2010, 695, 1518.
37. Lin, S.; Song, C.-X.; Cai, G.-X.; Wang, W.-H.; Shi, Z.-J. J. Am. Chem. Soc. 2008, 130,
12901.
ꢁ
ꢁ
38. Cui, D.-M.; Yu, K.-R.; Zhang, C. Synlett 2009, 1103.
39. Yamamoto, Y.; Takada, S.; Miyaura, N. Organometallics 2009, 28, 152.
40. Wang, J.; Cui, Z.; Zhang, Y.; Li, H.; Wu, L.-M.; Liu, Z. Org. Biomol. Chem. 2011, 9,
663.
41. See Ref. 15.
42. Lin, M.; Hao, L.; Liu, X.-T.; Chen, Q.-Z.; Wu, F.; Yan, P.; Xu, S.-X.; Chen, X.-L.; Wen,
10. Walter, R.; Kirchner, S.; Franz, R. U.S. Patent 6,399,804, 2002.
J.-J.; Zhan, Z.-P. Synlett 2011, 665.
11. Ball, R. G.; Graham, W. A. G.; Heinekey, D. M.; Hoyano, J. K.; McMaster, A. D.;
Mattson, B. M.; Michel, S. T. Inorg. Chem. 1990, 29, 2023.
43. Niggemann, M.; Meel, M. J. Angew. Chem., Int. Ed. 2010, 49, 3684.
44. Kuninobu, Y.; Ueda, H.; Takai, K. Chem. Lett. 2008, 37, 878.