KOtBu-Mediated Domino Isomerization and Functionalization of Aromatic Allylic Alcohols

Article abstract of DOI:10.1002/ejoc.201700440

Transition-metal- as well as ligand-free base-mediated domino isomerization and alkylation of allylic alcohols is presented. This protocol features the conversion of simple allylic alcohols into the corresponding ketones through isomerization in the presence of a simple base. Significantly, these in situ generated ketones subsequently undergo alkylation with styrenes as electrophiles, in a domino one-pot fashion, as an atom- and step-economical chemical process.

Full text of DOI:10.1002/ejoc.201700440

DOI: 10.1002/ejoc.201700440
Full Paper
Domino Internal Hydrogen Transfer
KOtBu-Mediated Domino Isomerization and Functionalization of
Aromatic Allylic Alcohols
Basuli Suchand[a] and Gedu Satyanarayana*[a]
Abstract: Transition-metal- as well as ligand-free base-medi- in the presence of a simple base. Significantly, these in situ
ated domino isomerization and alkylation of allylic alcohols is generated ketones subsequently undergo alkylation with
presented. This protocol features the conversion of simple allylic styrenes as electrophiles, in a domino one-pot fashion, as an
alcohols into the corresponding ketones through isomerization atom- and step-economical chemical process.
Introduction
long and tedious synthetic routes. Significantly, in this protocol,
the internal isomerization and alkylation sequence is solely
enabled by a single base. To the best of our knowledge, this is
the first example of transition-metal- and ligand-free isomeriza-
tion of allylic alcohols followed by functionalization.
The development of domino and atom-efficient synthetic trans-
formations[1] is much sought-after in organic chemistry. Particu-
larly, establishing the strategies without the aid of transition-
metal catalysts is of pronounced interest.[2] In this regard, transi-
tion-metal-catalyzed internal rearrangements of allylic alcohols
into their corresponding carbonyl compounds have been well
established, as atom-economical synthetic processes.[3] Though
these methods have proved to be atom-efficient with good
substrate scope, there are some limitations with regards to
safety, cost and risk of heavy-metal residues.[4] Therefore, devel-
opments of new synthetic strategies accessible without the aid
of transition-metal catalysts are highly desirable. In this context,
metal-free base (NaH) mediated isomerization of allyic alcohols
has been described.[5a,5b] Recently, Kang et al. disclosed the first
phenanthroline- and tert-butoxide-catalyzed isomerization of
allylic alcohols, under transition-metal-free conditions.[5c] Very
recently, the research group of Martín-Matute presented a mild
base-catalyzed stereospecific isomerization of electron-defi-
cient allylic alcohols and ethers.[6] Subsequently, Ghorai and co-
workers reported an unprecedented route for the formation of
1,2,4-triarylbenzenes from α-arylcinnamyl alcohols promoted
by a simple base.[7]
In continuation of our ongoing research interests in the de-
velopment of one-pot domino processes,[8] herein, we present
a domino one-pot isomerization of allylic alcohols and subse-
quent α-alkylation of the obtained ketones using styrenes as
electrophiles. Notably, the process is triggered by a simple base
without the aid of any transition-metal catalyst or ligand. This
route provides an easy access to interesting carbon-tethered
ketones, useful synthons in organic chemistry.[9] This strategy
makes use of readily available allylic alcohols by eliminating
Results and Discussion
We proposed that isomerization and subsequent alkylation of
allylic alcohols could be performed in a one-pot operation by
means of an appropriate base. Thus, the entire process turned
out to be efficient without the need to isolate the intermediate
ketones. We also presumed that alkylation at the α-carbon
atom of ketones could be feasible by using styrene as electro-
phile.[10] Initially, the reaction was carried out with allylic alco-
hol 1a and styrene (2a), in the presence of the base KOtBu
(1.5 equiv.) in DMF at 120 °C for 12 h. To our delight, as antici-
pated, the alkylated ketone 3aa was obtained in moderate yield
(Table 1, Entry 1). The use of toluene as the solvent showed
more or less the same result (Table 1, Entry 2). On the other
hand, the reaction in CH3CN gave the product in poor yield
(Table 1, Entry 3). Gratifyingly, the reaction in THF furnished
product 3aa in fair yield (Table 1, Entry 4). When a catalytic
amount of base (50 mol-%) was used, the simple ketone 4a was
obtained as the major product along with a poor quantity of
3aa (Table 1, Entry 5). On the other hand, the reaction at room
temperature stopped after isomerization and exclusively af-
forded 4a (Table 1, Entry 6). The effect of the base NaOtBu was
only moderate and furnished both 3aa and 4a (Table 1, Entries
7 and 8). Furthermore, reactions using other bases were inferior
(Table 1, Entries 9 to 15). Almost no change was observed in
the yield of product 3aa upon increasing the amount of KOtBu
(Table 1, Entry 16).
Since the reaction with 50 mol-% of the base KOtBu at 80 °C
or with 1.5 equiv. KOtBu at room temperature selectively fur-
nished the simple ketone 4a (Table 1, Entries 5 and 6), to check
the scope and generality of the method, the isomerization reac-
tion was inspected with allylic alcohols in the presence of
KOtBu (50 mol-%) at room temperature. Delightfully, the reac-
[a] Department of Chemistry, Indian Institute of Technology Hyderabad,
Kandi, 502285 Sangareddy, Telangana, India
E-mail: gvsatya@iith.ac.in
https://sites.google.com/site/gsresearchgrouphomepage/home
Supporting information for this article is available on the WWW under
https://doi.org/10.1002/ejoc.201700440.
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Table 1. Optimization studies for the formation of 3aa.[a]
Entry
Base (equiv.)
Solvent
Temp. [°C]
Time [h]
Yield of 3aa [%][b]
Yield of 4a [%][b]
[c]
[c]
[c]
[c]
1
2
KOtBu (1.5)
KOtBu (1.5)
KOtBu (1.5)
KOtBu (1.5)
KOtBu (0.5)
KOtBu (1.5)
NaOtBu (1.5)
NaOtBu (1.5)
Cs2CO3 (1.5)
Cs2CO3 (1.5)
Cs2CO3 (1.5)
K2CO3 (1.5)
K3PO4 (1.5)
NEt3 (1.5)
DMF
toluene
CH3CN
THF
120
100
100
80
12
8
53
50
37
67
15
–
–
–
–
3
6
4
6
6
15
8
10
12
12
12
15
12
15
10
6
5
THF
80
70
60
10
10
59
55
[d]
6
THF
THF
DMSO
THF
r.t.
80
100
80
–
7
48
45
8
[d]
9
–
[d]
10
11
12
13
14
15
16
DMF
toluene
THF
100
100
80
–
[d]
–
40
[e]
[e]
–
–
–
–
[e]
[e]
[e]
THF
80
–
[e]
THF
80
–
KOH (1.5)
THF
80
15
65
30
[c]
KOtBu (2.0)
THF
80
–
[a] Unless otherwise mentioned, all the reactions were carried out by using 1-phenylprop-2-en-1-ol (1a; 100.5 mg, 0.75 mmol) and styrene (2a;
85.8 mg, 0.82 mmol), solvent (1.5 mL). [b] Isolated yields of chromatographically pure products. [c] Simple ketone 4a was not observed. [d] Alkylated
ketone 3aa was not observed. [e] Starting material was recovered.
Table 2. Synthesis of simple ketones 4a–n from allylic alcohols 1a–n.[a]
tion was successful with different allylic alcohols 1a–n and af-
forded the corresponding ketones 4a–n in fair to very good
yields (Table 2). The reaction proceeded with simple and alkyl
functionalities present on the aromatic ring (4a–e; Table 2).
Notably, the reaction was compatible with F and Cl substituents
(4f and 4g; Table 2) and successful with electron-donating OMe
and methylenedioxy groups (4h–l; Table 2). Interestingly, the
reaction proceeded with 1,3-diarylallylic alcohol 1m and 1-(p-
tolyl)but-2-en-1-ol (1n) (4m and 4n; Table 2), while the reaction
with 1-(2-bromophenyl)prop-2-en-1-ol did not progress. This
may be due to increased steric crowding around the allylic alco-
hol moiety by the ortho-bromo substituent. Having the opti-
mized conditions in hand for the formation of alkylated ketone
3aa (Table 1, Entry 4), to further check the scope and applicabil-
ity of the strategy, we performed reactions between allylic alco-
hols 1a–n and styrenes 2a–e. Gratifyingly, the reactions were
quite successful with various styrenes 2a–e and furnished the
corresponding alkylated ketones 3aa–nd in moderate to fair
yields (Table 3). Interestingly, the reaction succeeded with allylic
alcohols 1a–n bearing various substituents on the aromatic ring
(i.e. F, Cl, alkyl and OMe). The reaction proceeded also smoothly
with Cl, Br and methyl groups on the aromatic ring of styrenes
2a–e (Table 3). Thus, products 3aa–nd with these interesting
substituents, especially Cl and Br groups, would permit further
functionalizations for the accomplishment of diversified com-
pounds. It is worth mentioning that the reaction was unsuccess-
ful with aliphatic allylic alcohols such as 1-phenylbut-3-en-2-
ol, 1-cyclohexylprop-2-en-1-ol and cyclohex-2-enol. This may be
due to the less reactive nature of aliphatic alcohols.
Since the formation of isomerized ketone product from the
corresponding allylic alcohol was observed with use of sub-
stoichiometric quantities of base (Table 1), the isomerization
was carried out by using 50 mol-% base (Table 2). Contrarily,
stoichiometric amounts of base were necessary to drive the re-
action through isomerization followed by alkylation in one pot
[a] Isolated yields of chromatographically pure products 1a–n.
3887 © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Table 3. Synthesis of alkylated ketones 3aa–nd from allylic alcohols 1a–n and styrenes 2a–e.[a]
[a] Isolated yields of chromatographically pure products 3aa–nd.
(Table 3). The latter may be justified based on the fact that
more base is essential to force the reaction to give the final
product, particularly, in the alkylation step. A kinetic study has
been conducted under standard conditions (Table 2), by using
0.5 equiv. (50 mol-%) as well as 1 equiv. (100 mol-%) base, and
the progress of the reaction was studied at different time inter-
vals (Figure 1). As expected, the conversion of the product in-
creased with time in both cases. Conversion into the ketone
was relatively faster with 1 equiv. of base when compared with
that in the presence of 50 mol-%, which is quite obvious.
From the above observations, ketones seemed to be poten-
tial reaction intermediates. To confirm this, we carried out a
control experiment with a ketone and 4-bromostyrene. As
anticipated, the alkylated product 3ad was obtained in 71 %
yield (Scheme 1a). It was also observed that with use of 1 and
3 equiv. of TEMPO, the reaction was partially and completely
Figure 1. Plot of conversion of product versus time in the presence of 50 mol-%
and 100 mol-% of catalyst.
inhibited, respectively (Scheme 1b and c). This may support
some sort of radical formation. On the basis of this observation
and the report by Kang,[5c] the radical mechanism may be pro-
posed as depicted in Scheme 2b. On the other hand, when a 4j (18 % isolated yield) with no deuterium incorporation either
simple isomerization was carried out in a 1:1 mixture of D2O at the α or the ꢀ position of the ketone (Scheme 1d). Contrarily,
(0.25 mL)/THF (0.25 mL), the reaction furnished ketone product the reaction in D2O (5.0 equiv.)/toluene (0.5 mL) furnished prod-
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uct 4m-d (9 % isolated yield) with deuterium incorporation only
at the α position along with undeuterated product 4m (15 %
isolated yield) (Scheme 1e). Therefore, under these anionic con-
ditions (Scheme 1d and e), probably the reaction proceeds
through a contact or intimate ion pair by a relatively rapid de-
protonation/protonation path, at least up to the formation of
enolate B (Scheme 2a). Since the intermediate A is less stable
than B, the intermediate B can come in close contact with D2O,
and hence deuteration takes place at the α position. Based on
this observation, the plausible mechanism for isomerization at
room temperature is as shown in Scheme 2a.
Scheme 2. Plausible reaction mechanism for the synthesis of ketones 3/4
from allylic alcohols 1.
A second deprotonation of A would give carbanion B. Finally,
reprotonation of B would lead to the formation of ketone 4. On
the other hand, when the reaction was performed in the pres-
ence of styrene (2) at 80 °C, it may have proceeded through a
radical path (Scheme 2b). Thus, oxide A upon exposure to the
base KOtBu and the solvent THF would yield radical oxide C,
which can isomerize to D and then to E. Now, E could remove
a proton from another allylic alcohol 1 and generate radical F.
Then, hydrogen radical transfer from A to F would occur and
furnish 4 and C. Finally, the reaction of 4 with styrene (2) would
generate product 3. Alternatively, radical F would combine with
styrene (2) to give 3 (Scheme 2b).
Scheme 1. Control experiments.
Conclusions
The mechanism of this isomerization of allylic alcohols cer-
tainly differs from those of transition-metal-catalyzed proc- We have developed a transition-metal- and ligand-free domino
esses,[6] in consideration of the well-established mechanistic one-pot isomerization and alkylation sequence of allylic alco-
studies of recent reports on the isomerization of allylic alcohols hols promoted by a simple base. The process involves the for-
using simple bases.[5–7,12] Hence, on the basis of control experi- mation of the corresponding carbonyl compounds that un-
ments and above reports, this base-promoted allylic isomeriza- dergo in situ α-alkylation in the presence of styrenes as electro-
tion would proceed through a deprotonation/reprotonation se- philes. The reaction works under relatively mild conditions and
quence at room temperature. Initially, KOtBu would de- is compatible with various functional groups on both aromatic
protonate the allylic alcohol 1 and generate the oxide ion A. rings. The strategy enabled the synthesis of a variety of alkyl-
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layers were dried with Na2SO4 and filtered. Evaporation of the sol-
vent under reduced pressure and purification of the crude material
by silica gel column chromatography (petroleum ether/ethyl acet-
ate) furnished the products 3aa–nd (119.0–185.7 mg, 52–68 %) as
viscous liquids.
ated ketones, useful synthons in organic synthesis. Certainly,
this process (i.e. isomerization followed by alkylation domino
reaction) is advantageous over obtaining the same product by
performing an alkylation reaction of the corresponding ketone:
The same ketone could be synthesized in two steps from benz-
aldehyde with a Grignard reaction and an oxidation protocol
(two steps), followed by a separate alkylation step (in total three
steps). Advantageously, the present strategy provides the same
product in two steps (i.e. vinyl-Grignard- and base-mediated
isomerization and alkylation sequence).
2-Methyl-1,4-diphenylbutan-1-one (3aa): GP-2 was performed
with allylic alcohol 1a (100.5 mg, 0.75 mmol) and styrene 2a
(85.8 mg, 0.825 mmol) in the presence of KOtBu (126.0 mg,
1.125 mmol) in dry THF (1.5 mL), and the reaction mixture was
stirred at 80 °C for 6 h. Purification of the crude material by silica
gel column chromatography (petroleum ether/ethyl acetate, 95:05
to 93:07) furnished product 3aa (119.6 mg, 67 %) as a colourless
viscous liquid [TLC control (petroleum ether/ethyl acetate, 95:05),
Rf(1a) = 0.20, Rf(3aa) = 0.70, UV detection]. IR (MIR-ATR, 4000–
Experimental Section
600 cm–1): νmax = 2965, 2923, 2841, 1670, 1622, 1450, 1372, 1310,
˜
General: IR spectra were recorded with an FTIR spectrophotometer.
1H NMR spectra were recorded with a 400 MHz spectrometer at
295 K in CDCl3; chemical shifts (δ, ppm) and coupling constants (J,
Hz) are reported in standard fashion with reference to either inter-
nal standard tetramethylsilane (TMS) (δH = 0.00 ppm) or CHCl3 (δH =
7.25 ppm). 13C NMR spectra were recorded with an 100 MHz spec-
trometer at room temp. in CDCl3; chemical shifts (δ, ppm) are re-
ported relative to CHCl3 [δC = 77.00 ppm (central line of triplet)]. In
the 13C NMR spectra, the nature of the carbon atoms (C, CH, CH2
and CH3) was determined by recording the DEPT-135 spectra. In the
1H NMR spectra the following abbreviations are used: s = singlet,
d = doublet, t = triplet, q = quartet, quint = quintet, sept = septet,
dd = doublet of doublets, m = multiplet and br. s = broad singlet.
High-resolution mass spectra (HRMS) were recorded with Q-TOF
electron spray ionization (ESI) and atmospheric-pressure chemical
ionization (APCI) modes. All small-scale reactions were carried out
by using Schlenk tubes. Reactions were monitored by TLC on silica
gel with use of a combination of hexane and ethyl acetate as the
eluent. Reactions were generally performed under argon or nitro-
gen. Solvents were distilled prior to use; petroleum ether with a
boiling range of 60–80 °C was used. Acme's silica gel (60–120 mesh)
was used for column chromatography (approximately 20 g per 1 g
of crude material). The allylic alcohols 1a–n are reported in the
literature[11] and alkenes 2a–e are commercially available.
1251, 1123, 907, 759, 682 cm–1. 1H NMR (CDCl3, 400 MHz): δ = 7.86
(dd, J = 8.5 Hz and J = 1.2 Hz, 2 H, Ar-H), 7.57–7.52 (m, 1 H, Ar-H),
7.46–7.42 (m, 2 H, Ar-H), 7.27 (t, J = 7.5 Hz, 2 H, Ar-H), 7.21–7.14 (m,
3 H, Ar-H), 3.49–3.44 (m, 1 H, CH), 2.67–2.63 (m, 2 H, CH2), 2.22–
2.13 (m, 1 H, CH2), 1.79–1.73 (m, 1 H, CH2), 1.23 (d, J = 6.8 Hz, 3 H,
CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 204.1 (s, C=O), 141.7 (s,
Ar-C), 136.5 (s, Ar-C), 132.8 (d, Ar-CH), 128.6 (d, 2 C, Ar-CH), 128.4
(d, 2 C, Ar-CH), 128.3 (d, 2 C, Ar-CH), 128.2 (d, 2 C, Ar-CH), 125.9 (d,
Ar-CH), 39.7 (d, CH), 35.1 (t, CH2), 33.4 (t, CH2), 17.2 (q, CH3) ppm.
HRMS (ESI+): calcd. for C17H19O [M + H]+ 239.1430; found 239.1426.
4-(2-Chlorophenyl)-2-methyl-1-phenylbutan-1-one (3ab): GP-2
was performed with allylic alcohol 1a (100.5 mg, 0.75 mmol) and
alkene 2b (113.8 mg, 0.825 mmol) in the presence of KOtBu
(126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the reaction mix-
ture was stirred at 80 °C for 6 h. Purification of the crude material
by silica gel column chromatography (petroleum ether/ethyl acet-
ate, 95:05 to 93:07) furnished product 3ab (122.4 mg, 60 %) as a
colourless viscous liquid [TLC control (petroleum ether/ethyl acet-
ate, 95:05), Rf(1a) = 0.20, Rf(3ab) = 0.70, UV detection]. IR (MIR-ATR,
4000–600 cm–1): νmax = 2955, 2926, 2876, 1671, 1612, 1454, 1371,
˜
1220, 1151, 971, 709, 680 cm–1. 1H NMR (CDCl3, 400 MHz): δ = 7.91
(d, J = 7.3 Hz, 2 H, Ar-H), 7.57–7.53 (m, 1 H, Ar-H), 7.47–7.43 (m, 2
H, Ar-H), 7.32–7.30 (m, 1 H, Ar-H), 7.17–7.10 (m, 3 H, Ar-H), 3.54–
3.46 (m, 1 H, CH), 2.78–2.74 (m, 2 H, CH2), 2.20–2.11 (m, 1 H, CH2),
1.80–1.71 (m, 1 H, CH2), 1.26 (d, J = 6.8 Hz, 3 H, CH3) ppm. 13C NMR
(CDCl3, 100 MHz): δ = 203.7 (s, C=O), 139.4 (s, Ar-C), 136.4 (s, Ar-C),
133.7 (s, Ar-C), 132.9 (d, Ar-CH), 130.4 (d, Ar-CH), 129.4 (d, Ar-CH),
128.6 (d, 2 C, Ar-CH), 128.2 (d, 2 C, Ar-CH), 127.4 (d, Ar-CH), 126.7
(d, Ar-CH), 40.1 (d, CH), 33.3 (t, CH2), 31.3 (t, CH2), 17.3 (q, CH3)
ppm. HRMS (ESI+): calcd. for C17H17ClNaO [M + Na]+ 295.0860; found
295.0864.
General Procedure for the Preparation of 4a–n (GP-1): Allylic
alcohols 1a–n (100.5–168.0 mg, 0.75 mmol) and KOtBu (42.0 mg,
0.375 mmol) were placed in a Schlenk tube. Then, dry THF (1.5 mL)
was added with a syringe, and the reaction mixture was stirred at
room temperature. The progress of the reaction was monitored by
TLC until the starting material was completely consumed. Then, the
reaction was quenched by the addition of aqueous NaCl solution
and the mixture then extracted with ethyl acetate (3 × 15 mL). The
organic layers were dried with Na2SO4 and filtered. Evaporation of
the solvent under reduced pressure and purification of the crude
material by silica gel column chromatography (petroleum ether/
ethyl acetate) furnished products 4a–n (96.4–150.0 mg, 56–80 %)
as viscous liquids. All compounds are reported in the litera-
ture.[3a,3b,3k,5,6]
4-(2-Bromophenyl)-2-methyl-1-phenylbutan-1-one (3ac): GP-2
was performed with allylic alcohol 1a (100.5 mg, 0.75 mmol) and
alkene 2c (150.0 mg, 0.825 mmol) in the presence of KOtBu
(126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the reaction mix-
ture was stirred at 80 °C for 6 h. Purification of the crude material
by silica gel column chromatography (petroleum ether/ethyl acet-
ate, 95:05 to 93:07) furnished product 3ac (161.0 mg, 68 %) as a
colourless viscous liquid [TLC control (petroleum ether/ethyl acet-
General Procedure for the Preparation of 3aa–nd (GP-2): Allylic
alcohols 1a–n (100.5–168.0 mg, 0.75 mmol), alkenes 2a–e (97.3–
150.0 mg, 0.825 mmol) and KOtBu (126.0 mg, 1.125 mmol) were ate, 95:05), Rf(1a) = 0.20, Rf(3ac) = 0.70, UV detection]. IR (MIR-ATR,
placed in a Schlenk tube. Then, dry THF (1.5 mL) was added with a
syringe, and the reaction mixture was stirred at 80 °C. The progress
4000–600 cm–1): ν
= 2963, 2941, 2846, 1670, 1622, 1454, 1372,
˜
max
1320, 1151, 971, 719, 680 cm–1. 1H NMR (CDCl3, 400 MHz): δ = 7.92
of the reaction was monitored by TLC until the starting material (dd, J = 8.5 Hz and J = 1.2 Hz, 2 H, Ar-H), 7.57–7.43 (m, 4 H, Ar-H),
was consumed. Then, the reaction mixture was removed from the
oil bath and cooled to room temperature. The reaction was
quenched by the addition of aqueous NaCl solution and the mix-
ture then extracted with ethyl acetate (3 × 15 mL). The organic
7.21–7.15 (m, 2 H, Ar-H), 7.06–7.02 (m, 3 H, Ar-H), 3.48–3.55 (m, 1
H, CH), 2.80–2.73 (m, 2 H, CH2), 2.19–2.10 (m, 1 H, CH2), 1.80–1.71
(m, 1 H, CH2), 1.27 (d, J = 6.8 Hz, 3 H, CH3) ppm. 13C NMR (CDCl3,
100 MHz): δ = 203.7 (s, C=O), 141.1 (s, Ar-C), 136.4 (s, Ar-C), 132.9
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(d, Ar-CH), 132.8 (d, Ar-CH), 130.4 (d, Ar-CH), 128.6 (d, 2 C, Ar-CH),
203.4 (s, C=O), 143.7 (s, Ar-C), 141.2 (s, Ar-C), 133.9 (s, Ar-C), 132.8
128.3 (d, 2 C, Ar-CH), 127.7 (d, Ar-CH), 127.4 (d, Ar-CH), 124.3 (s, Ar- (d, Ar-CH), 130.4 (d, Ar-CH), 129.3 (d, 2 C, Ar-CH), 128.4 (d, 2 C, Ar-
C), 40.1 (d, CH), 33.8 (t, CH2), 33.5 (t, CH2), 17.3 (q, CH3) ppm. HRMS
CH), 127.6 (d, Ar-CH), 127.4 (d, Ar-CH), 124.4 (s, Ar-C), 39.9 (d, CH),
33.9 (t, CH2), 33.6 (t, CH2), 21.6 (q, Ar-CH3) 17.4 (q, CH3) ppm. HRMS
(ESI+): calcd. for C18H20BrO [M + H]+ 334.0706; found 334.0711.
(ESI+): calcd. for C17H18BrO [M + H]+ 317.0536; found 317.0543.
4-(4-Bromophenyl)-2-methyl-1-phenylbutan-1-one (3ad): GP-2
was performed with allylic alcohol 1a (100.5 mg, 0.75 mmol) and
alkene 2d (150.0 mg, 0.825 mmol) in the presence of KOtBu
4-(2-Chlorophenyl)-1-(4-ethylphenyl)-2-methylbutan-1-one
(3cb): GP-2 was performed with allylic alcohol 1c (121.5 mg,
(126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the reaction mix- 0.75 mmol) and alkene 2b (113.8 mg,0.825 mmol) in the presence
ture was stirred at 80 °C for 6 h. Purification of the crude material of KOtBu (126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the
by silica gel column chromatography (petroleum ether/ethyl acet- reaction mixture was stirred at 80 °C for 7 h. Purification of the
ate, 95:05 to 93:07) furnished product 3ad (139.8 mg, 59 %) as a crude material by silica gel column chromatography (petroleum
colourless viscous liquid [TLC control (petroleum ether/ethyl acet- ether/ethyl acetate, 95:05 to 93:07) furnished product 3cb
ate, 95:05), Rf(1a) = 0.20, Rf(3ad) = 0.70, UV detection]. IR (MIR-ATR,
(144.1 mg, 64 %) as a colourless viscous liquid [TLC control (petro-
4000–600 cm–1): νmax = 2930, 2913, 1686, 1466, 1367, 1302, 1055, leum ether/ethyl acetate, 95:05), Rf(1c) = 0.20, Rf(3cb) = 0.70, UV
˜
1
945, 801 1089, 934, 718 cm–1. H NMR (CDCl3, 400 MHz): δ = 7.86
(dd, J = 8.3 Hz and 1.4 Hz, 2 H, Ar-H), 7.57–7.53 (m, 1 H, Ar-H), 7.44
detection]. IR (MIR-ATR, 4000–600 cm–1): νmax = 2963, 2943, 2875,
˜
1681, 1615, 1466, 1375, 1327, 1151, 924, 840, 709, 686 cm–1 1H
.
(t, J = 7.5 Hz, 2 H, Ar-H), 7.37 (d, J = 8.3 Hz, 2 H, Ar-H), 7.0 (d, J = NMR (CDCl3, 400 MHz): δ = 7.85 (d, J = 8.3 Hz, 2 H, Ar-H), 7.33–7.26
8.3 Hz, 2 H, Ar-H), 3.49–3.40 (m, 1 H, CH), 2.61–2.54 (m, 2 H, CH2), (m, 3 H, Ar-H), 7.17–7.09 (m, 3 H, Ar-H), 3.53–3.44 (m, 1 H, CH), 2.78–
2.19–2.10 (m, 1 H, CH2), 1.76–1.67 (m, 1 H, CH2), 1.22 (d, J = 6.8 Hz,
2.67 (m, 4 H, CH2), 2.19–2.10 (m, 1 H, CH2), 1.79–1.70 (m, 1 H, CH2),
3 H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 203.9 (s, C=O), 140.7 1.26 (2 d, J = 6.8 Hz, 2 × 3 H, CH3) ppm. 13C NMR (CDCl3, 100 MHz):
(s, Ar-C), 136.4 (s, Ar-C), 133.0 (d, Ar-CH), 131.4 (d, 2 C, Ar-CH), 130.2
(d, 2 C, Ar-CH), 128.6 (d, 2 C, Ar-CH), 128.2 (d, 2 C, Ar-CH), 119.6 (s,
δ = 203.4 (s, C=O), 149.8 (s, Ar-C), 139.5 (s, Ar-C), 134.1 (s, Ar-C),
133.9 (s, Ar-C), 130.4 (d, Ar-CH), 129.4 (d, Ar-CH), 128.5 (d, 2 C, Ar-
Ar-C), 39.6 (d, CH), 34.9 (t, CH2), 32.9 (t, CH2), 17.5 (q, CH3) ppm. CH), 128.1 (d, 2 C, Ar-CH), 127.4 (d, Ar-CH), 126.7 (d, Ar-CH), 40.0 (d,
HRMS (ESI+): calcd. for C17H18BrO [M + H]+ 317.0536; found
317.0543.
CH), 33.4 (t, CH2), 31.3 (t, CH2), 28.9 (t, CH2), 17.4 (q, CH3), 15.2 (q,
Ar-CH2CH3) ppm. HRMS (ESI+): calcd. for C19H22ClO [M + H]+
301.1354; found 301.1356.
4-(2-Chlorophenyl)-2-methyl-1-(p-tolyl)butan-1-one (3bb): GP-2
was performed with allylic alcohol 1b (111.0 mg, 0.75 mmol) and
alkene 2b (138.8 mg,0.825 mmol) in the presence of KOtBu
4-(2-Bromophenyl)-1-(4-ethylphenyl)-2-methylbutan-1-one
(3cc): GP-2 was performed with allylic alcohol 1c (121.5 mg,
(126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the reaction mix- 0.75 mmol) and alkene 2c (150.0 mg,0.825 mmol) in the presence
ture was stirred at 80 °C for 8 h. Purification of the crude material of KOtBu (126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the
by silica gel column chromatography (petroleum ether/ethyl acet- reaction mixture was stirred at 80 °C for 8 h. Purification of the
ate, 95:05 to 93:07) furnished product 3bb (124.4 mg, 60 %) as a crude material by silica gel column chromatography (petroleum
colourless viscous liquid [TLC control (petroleum ether/ethyl acet- ether/ethyl acetate, 95:05 to 93:07) furnished product 3cc
ate, 95:05), Rf(1b) = 0.20, Rf(3bb) = 0.70, UV detection]. IR (MIR-ATR,
(165.6 mg, 64 %) as a colourless viscous liquid [TLC control (petro-
4000–600 cm–1): νmax = 2945, 2925, 2846, 1672, 1612, 1454, 1371, leum ether/ethyl acetate, 95:05), Rf(1c) = 0.20, Rf(3cc) = 0.70, UV
˜
1220, 1151, 970, 759, 682 cm–1. 1H NMR (CDCl3, 400 MHz): δ = 7.81 detection]. IR (MIR-ATR, 4000–600 cm–1): νmax = 2960, 2943, 2852,
˜
1
(d, J = 8.3 Hz, 2 H, Ar-H), 7.32–7.30 (m, 1 H, Ar-H), 7.24 (d, J = 7.3 Hz,
2 H, Ar-H), 7.17–7.10 (m, 3 H, Ar-H), 3.52–3.43 (m, 1 H, CH), 2.79–
2.72 (m, 2 H, CH2), 2.40 (s, 3 H, Ar-CH3), 2.19–2.10 (m, 1 H, CH2),
1.79–1.76 (m, 1 H, CH2), 1.25 (d, J = 6.8 Hz, 3 H, CH3) ppm. 13C NMR
(CDCl3, 100 MHz): δ = 203.4 (s, C=O), 143.6 (s, Ar-C), 139.5 (s, Ar-C),
133.9 (s, 2 C, Ar-C), 130.4 (d, Ar-CH), 129.4 (d, Ar-CH), 129.3 (d, 2 C,
Ar-CH), 128.4 (d, 2 C, Ar-CH), 127.4 (d, Ar-CH), 126.7 (d, Ar-CH), 39.9
1668, 1607, 1556, 1370, 1237, 1151, 904, 845, 709. H NMR (CDCl3,
400 MHz): δ = 7.86 (d, J = 8.3 Hz, 2 H, Ar-H), 7.50 (dd, J = 8.0 and
1.2 Hz, 1 H, Ar-H), 7.27 (d, J = 8.3 Hz, 2 H, Ar-H), 7.21–7.15 (m, 2 H,
Ar-H), 7.06–7.01 (m, 1 H, Ar-H), 3.54–3.46 (m, 1 H, CH), 2.78–2.67 (m,
4 H, CH2), 2.18–2.09 (m, 1 H, CH2), 1.79–1.70 (m, 1 H, CH2), 1.27 (2
d, J = 6.8 Hz, 2 × 3 H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ =
203.4 (s, C=O), 149.8 (s, Ar-C), 141.2 (s, Ar-C), 134.1 (s, Ar-C), 132.8
(d, CH), 33.4 (t, CH2), 31.3 (t, CH2), 21.6 (q, Ar-CH3) 17.4 (q, CH3) (d, Ar-CH), 130.4 (d, Ar-CH), 128.5 (d, 2 C, Ar-CH), 128.1 (d, 2 C, Ar-
ppm. HRMS (ESI+): calcd. for C18H20ClO [M + H]+ 287.1197; found
287.1206.
CH), 127.6 (d, Ar-CH), 127.4 (d, Ar-CH), 124.4 (s, Ar-C), 40.0 (d, CH),
33.9 (t, CH2), 33.6 (t, CH2), 28.9 (t, Ar-CH2), 17.4 (q, CH3), 15.2 (q, Ar-
CH2CH3) ppm. HRMS (ESI+): calcd. for C19H22BrO [M + H]+ 345.0849;
found 345.0856.
4-(2-Bromophenyl)-2-methyl-1-(p-tolyl)butan-1-one (3bc): GP-2
was performed with allylic alcohol 1b (111.0 mg, 0.75 mmol) and
alkene 2c (150.0 mg,0.825 mmol) in the presence of KOtBu
4-(4-Bromophenyl)-1-(4-ethylphenyl)-2-methylbutan-1-one
(126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the reaction mix- (3cd): GP-2 was performed with allylic alcohol 1c (121.5 mg,
ture was stirred at 80 °C for 8 h. Purification of the crude material 0.75 mmol) and alkene 2d (150 mg,0.825 mmol) in the presence of
by silica gel column chromatography (petroleum ether/ethyl acet- KOtBu (126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the reaction
ate, 95:05 to 93:07) furnished product 3bc (148.9 mg, 60 %) as a mixture was stirred at 80 °C for 8 h. Purification of the crude mate-
colourless viscous liquid [TLC control (petroleum ether/ethyl acet- rial by silica gel column chromatography (petroleum ether/ethyl
ate, 95:05), Rf(1b) = 0.20, Rf(3bc) = 0.70, UV detection]. IR (MIR-ATR, acetate, 95:05 to 93:07) furnished product 3cd (160.4 mg, 62 %) as
4000–600 cm–1): ν
= 2965, 2923, 2851, 1667, 1605, 1466, 1367, a colourless viscous liquid [TLC control (petroleum ether/ethyl acet-
˜
max
1302, 1055, 945, 801, 680 cm–1. 1H NMR (CDCl3, 400 MHz): δ = 7.82 ate, 95:05), Rf(1c) = 0.20, Rf(3cd) = 0.70, UV detection]. IR (MIR-ATR,
(d, J = 8.3 Hz, 2 H, Ar-H), 7.50 (dd, J = 7.8 and 0.9 Hz, 1 H, Ar-H),
7.24 (d, J = 7.8 Hz, 2 H, Ar-H), 7.21–7.15 (m, 2 H, Ar-H), 7.06–7.01
4000–600 cm–1): νmax = 2945, 2933, 2856, 1663, 1466, 1367, 1302,
˜
1055, 945, 801 cm–1 1H NMR (CDCl3, 400 MHz): δ = 7.80 (d, J =
.
(m, 1 H, Ar-H), 3.53–3.44 (m, 1 H, CH), 2.79–2.72 (m, 2 H, CH2), 2.40 8.3 Hz, 2 H, Ar-H), 7.38–7.36 (m, 2 H, Ar-H), 7.26 (d, J = 8.8 Hz, 2 H,
(s, 3 H, Ar-CH3), 2.18–2.09 (m, 1 H, CH2), 1.78–1.69 (m, 1 H, CH2),
Ar-H), 7.01 (d, J = 8.3 Hz, 2 H, Ar-H), 3.47–3.39 (m, 1 H, CH), 2.70 (q,
J = 7.8 Hz, 2 H, CH2), 2.59–2.52 (m, 2 H, CH2), 2.18–2.09 (m, 1 H,
1.25 (d, J = 6.8 Hz, 3 H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ =
Eur. J. Org. Chem. 2017, 3886–3895
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© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
CH2), 1.74–1.65 (m, 1 H, CH2), 1.24 (2 d, J = 6.8 Hz, 2 × 3 H, CH3)
ppm. 13C NMR (CDCl3, 100 MHz): δ = 203.5 (s, C=O), 150.0 (s, Ar-C),
140.8 (s, Ar-C), 134.1 (s, Ar-C), 131.4 (d, 2 C, Ar-CH), 130.2 (d, 2 C,
Ar-CH), 128.5 (d, 2 C, Ar-CH), 128.1 (d, 2 C, Ar-CH), 119.6 (s, Ar-C),
39.5 (d, CH), 35.0 (t, CH2), 32.9 (t, CH2), 28.9 (t, Ar-CH2), 17.6 (q, CH3),
15.2 (q, Ar-CH2CH3) ppm. HRMS (ESI+): calcd. for C19H22BrO [M + H]+
348.0863; found 348.0866.
7.16–7.08 (m, 5 H, Ar-H), 3.48–3.39 (m, 1 H, CH), 2.77–2.73 (m, 2 H,
CH2), 2.18–2.10 (m, 1 H, CH2), 1.79–1.70 (m, 1 H, CH2), 1.25 (d, J =
6.8 Hz, 3 H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 202.1 (s, C=
O), 164.3 (d, J = 254 Hz, Ar-CF), 139.2 (s, Ar-C), 133.9 (S, Ar-C), 132.7
(S, Ar-C), 130.9 (d, Ar-CH), 130.8 (d, Ar-CH), 130.5 (d, Ar-CH), 129.5
(d, Ar-CH), 127.5 (d, Ar-CH), 126.8 (d, Ar-CH), 115.8 (d, Ar-CH), 115.6
(d, Ar-CH), 40.0 (d, CH), 33.3 (t, CH2), 33.2 (t, CH2), 17.3 (q, CH3)
ppm. HRMS (ESI+): calcd. for C17H17ClFO [M + H]+ 291.0946; found
291.0945.
4-(2-Chlorophenyl)-1-(4-isopropylphenyl)-2-methylbutan-1-one
(3db): GP-2 was performed with allylic alcohol 1d (132.0 mg,
0.75 mmol) and alkene 2b (113.8 mg, 0.825 mmol) in the presence
of KOtBu (126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the
reaction mixture was stirred at 80 °C for 8 h. Purification of the
crude material by silica gel column chromatography (petroleum
ether/ethyl acetate, 95:05 to 93:07) furnished product 3db
4-(2-Bromophenyl)-1-(4-fluorophenyl)-2-methylbutan-1-one
(3fc): GP-2 was performed with allylic alcohol 1f (114.0 mg,
0.75 mmol) and alkene 2c (150.0 mg,0.825 mmol) in the presence
of KOtBu (126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the
reaction mixture was stirred at 80 °C for 8 h. Purification of the
(143.6 mg, 61 %) as a colourless viscous liquid [TLC control (petro- crude material by silica gel column chromatography (petroleum
leum ether/ethyl acetate, 95:05), Rf(1c) = 0.20, Rf(3db) = 0.70, UV ether/ethyl acetate, 95:05 to 93:07) furnished product 3fc (150.7 mg,
detection]. IR (MIR-ATR, 4000–600 cm–1): νmax = 2946, 2923, 2851,
60 %) as a colourless viscous liquid [TLC control (petroleum ether/
˜
1680, 1615, 1556, 1355, 1327, 1052, 904, 702, cm–1. 1H NMR (CDCl3,
400 MHz): δ = 7.86 (d, J = 8.8 Hz, 2 H, Ar-H), 7.33–7.28 (m, 3 H, Ar-
H), 7.19–7.11 (m, 3 H, Ar-H), 3.54–3.45 (m, 1 H, CH), 3.00–2.93 (m, 1
ethyl acetate, 95:05), Rf(1f) = 0.20, Rf(3fc) = 0.60, UV detection]. IR
(MIR-ATR, 4000–600 cm–1): νmax = 2965, 2923, 2851, 1667, 1605,
˜
1456, 1375, 1227, 1051, 974, 847, 749, 680 cm–1
.
1H NMR (CDCl3,
H, CH2), 2.78–2.74 (m, 2 H, CH2), 2.20–2.11 (m, 1 H, CH2), 1.79–1.72 400 MHz): δ = 7.94–7.91 (m, 2 H, Ar-H), 7.50 (dd, J = 7.8 and 0.9 Hz,
(m, 1 H, CH2), 1.29–1.26 (m, 9 H, CH3) ppm. 13C NMR (CDCl3,
1 H, Ar-H), 7.21–7.02 (m, 5 H, Ar-H), 3.49–3.41 (m, 1 H, CH), 2.79–
2.72 (m, 2 H, CH2), 2.17–2.08 (m, 1 H, CH2), 1.79–1.65 (m, 1 H, CH2),
100 MHz): δ = 203.4 (s, C=O), 154.4 (s, Ar-C), 139.5 (s, Ar-C), 134.2
(s, Ar-C), 133.9 (s, Ar-C), 130.4 (d, Ar-CH), 129.4 (d, Ar-CH), 128.5 (d, 1.26 (d, J = 6.8 Hz, 3 H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ =
2 C, Ar-CH), 127.4 (d, Ar-CH), 126.7 (d, Ar-CH), 126.7 (d,2 C, Ar-CH),
202.1 (s, C=O), 166.9 (s, Ar-C), 164.3 (d, J = 254 Hz, Ar-CF), 141.0 (s,
40.0 (d, CH), 34.2 (d, Ar-CH), 33.4 (t, CH2), 31.3 (t, CH2), 23.6 [q, Ar- Ar-C), 132.8 (d, Ar-CH), 130.9 (d, Ar-CH), 130.8 (d, Ar-CH), 130.4 (d,
CH(CH3)2], 17.4 (q, CH3) ppm. HRMS (ESI+): calcd. for C20H23ClNaO
Ar-CH), 127.7 (d, Ar-CH), 127.4 (d, Ar-CH), 124.3 (s, Ar-C), 115.8 (d,
Ar-CH), 115.5 (d, Ar-CH), 40.0 (d, CH), 33.8 (t, CH2), 33.5 (t, CH2), 17.2
(q, CH3) ppm. HRMS (ESI+): calcd. for C17H17BrFO [M + H]+ 335.0441;
found 335.0447.
[M + Na]+ 337.1330; found 337.1330.
4-(2-Bromophenyl)-1-(4-isopropylphenyl)-2-methylbutan-1-one
(3dc): GP-2 was performed with allylic alcohol 1d (132.0 mg,
0.75 mmol) and alkene 2c (150.0 mg,0.825 mmol) in the presence
of KOtBu (126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the
reaction mixture was stirred at 80 °C for 8 h. Purification of the
crude material by silica gel column chromatography (petroleum
ether/ethyl acetate, 95:05 to 93:07) furnished product 3dc
4-(2-Chlorophenyl)-1-(4-chlorophenyl)-2-methylbutan-1-one
(3gb): GP-2 was performed with allylic alcohol 1g (126.0 mg,
0.75 mmol) and alkene 2b (113.8 mg,0.825 mmol) in the presence
of KOtBu (126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the
reaction mixture was stirred at 80 °C for 8 h. Purification of the
(147.6 mg, 55 %) as a colourless viscous liquid [TLC control (petro- crude material by silica gel column chromatography (petroleum
leum ether/ethyl acetate, 95:05), Rf(1c) = 0.20, Rf(3dc) = 0.70, UV
ether/ethyl acetate, 95:05 to 93:07) furnished product 3gb
(137.7 mg, 60 %) as a colourless viscous liquid [TLC control (petro-
.
1H leum ether/ethyl acetate, 95:05), Rf(1g) = 0.20, Rf(3gb) = 0.60, UV
detection]. IR (MIR-ATR, 4000–600 cm–1): νmax = 2955, 2933, 2851,
˜
1667, 1608, 1466, 1379, 1237, 1051, 974, 840, 713, 689 cm–1
NMR (CDCl3, 400 MHz): δ = 7.87 (d, J = 8.8 Hz, 2 H, Ar-H), 7.52–7.49
(m, 1 H, Ar-H), 7.30 (d, J = 8.3 Hz, 2 H, Ar-H), 7.20–7.16 (m, 2 H, Ar-
H), 7.06–7.02 (m, 1 H, Ar-H), 3.53–3.48 (m, 1 H, CH), 2.93–2.90 (m, 1
detection]. IR (MIR-ATR, 4000–600 cm–1): νmax = 2967, 2925, 2854,
˜
1671, 1615, 1407, 1385, 1230, 1165, 970, 723, 700 cm–1
.
1H NMR
(CDCl3, 400 MHz): δ = 7.82 (d, J = 8.8 Hz, 2 H, Ar-H), 7.40 (d, J =
H, CH2), 2.78–2.74 (m, 2 H, CH2), 2.17–2.10 (m, 1 H, CH2), 1.78–1.71 8.8 Hz, 2 H, Ar-H), 7.33–7.30 (m, 1 H, Ar-H), 7.16–7.11 (m, 1 H, Ar-
(m, 1 H, CH2), 1.29–1.26 (m, 9 H, CH3) ppm. 13C NMR (CDCl3,
H), 3.46–3.38 (m, 1 H, CH), 2.79–2.72 (m, 2 H, CH2), 2.18–2.09 (m, 1
100 MHz): δ = 203.3 (s, C=O), 154.3 (s, Ar-C), 141.2 (s, Ar-C), 134.2
H, CH2), 1.78–1.69 (m, 1 H, CH2), 1.25 (d, J = 6.8 Hz, 3 H, CH3) ppm.
(s, Ar-C), 132.7 (d, Ar-CH), 130.4 (d, Ar-CH), 128.5 (d, 2 C, Ar-CH), 13C NMR (CDCl3, 100 MHz): δ = 202.4 (s, C=O), 139.3 (s, Ar-C), 139.2
127.6 (d, Ar-CH), 127.4 (d, Ar-CH), 126.7 (d,2 C, Ar-CH), 124.3 (s, Ar- (s, Ar-C), 134.6 (s, Ar-C), 133.9 (s, C, Ar-C), 130.4 (d, Ar-CH), 129.7 (d,
C), 40.0 (d, CH), 34.2 (d, Ar-CH), 33.9 (t, CH2), 33.6 (t, CH2), 23.6 [q, 2 C, Ar-CH), 129.5 (d, Ar-CH), 128.9 (d, 2 C, Ar-CH), 127.5 (d, Ar-CH),
Ar-CH(CH3)2], 17.4 (q, CH3) ppm. HRMS (ESI+): calcd. for C20H24BrO 126.8 (d, Ar-CH), 40.0 (d, CH), 33.3 (t, CH2), 31.2 (t, CH2), 17.2 (q,
[M + H]+ 359.1005; found 359.1011.
CH3) ppm. HRMS (ESI+): calcd. for C17H17Cl2O [M + H]+ 307.0651;
found 307.0646.
4-(2-Chlorophenyl)-1-(4-fluorophenyl)-2-methylbutan-1-one
(3fb): GP-2 was performed with allylic alcohol 1f (114.0 mg, 4-(2-Bromophenyl)-1-(4-chlorophenyl)-2-methylbutan-1-one
0.75 mmol) and alkene 2b (1113.8 mg,0.825 mmol) in the presence
of KOtBu (126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the
reaction mixture was stirred at 80 °C for 8 h. Purification of the
crude material by silica gel column chromatography (petroleum
ether/ethyl acetate, 95:05 to 93:07) furnished product 3fb
(3gc): GP-2 was performed with allylic alcohol 1g (126.0 mg,
0.75 mmol) and alkene 2c (150.0 mg,0.825 mmol) in the presence
of KOtBu (126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the
reaction mixture was stirred at 80 °C for 8 h. Purification of the
crude material by silica gel column chromatography (petroleum
(123.9 mg, 57 %) as a colourless viscous liquid [TLC control (petro- ether/ethyl acetate, 95:05 to 93:07) furnished product 3gc
leum ether/ethyl acetate, 95:05), Rf(1f) = 0.20, Rf(3fb) = 0.60, UV
(154.8 mg, 59 %) as a colourless viscous liquid [TLC control (petro-
leum ether/ethyl acetate, 95:05), Rf(1g) = 0.20, Rf(3gc) = 0.60, UV
detection]. IR (MIR-ATR, 4000–600 cm–1): νmax = 2926, 2853, 1671,
˜
1606, 1450, 1457, 1375, 1227, 975, 750 cm–1
.
1H NMR (CDCl3, detection]. IR (MIR-ATR, 4000–600 cm–1): νmax = 2955, 2933, 2852,
˜
1
400 MHz): δ = 7.93–7.90 (m, 2 H, Ar-H), 7.32–7.30 (m, 1 H, Ar-H), 1668, 1600, 1459, 1440, 1327, 1055, 945, 840, 749. H NMR (CDCl3,
Eur. J. Org. Chem. 2017, 3886–3895
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Full Paper
400 MHz): δ = 7.83 (d, J = 8.3 Hz, 2 H, Ar-H), 7.50 (dd, J = 7.8 and
0.9 Hz, 1 H, Ar-H), 7.41 (d, J = 8.3 Hz, 2 H, Ar-H), 7.22–7.14 (m, 2 H,
2857, 1730, 1599, 1565, 1502, 1460, 1440, 1244, 1160, 941, 750,
1
710 cm–1. H NMR (CDCl3, 400 MHz): δ = 7.52–7.50 (m, 2 H, Ar-H),
Ar-H), 7.07–7.02 (m, 1 H, Ar-H), 3.48–3.39 (m, 1 H, CH), 2.79–2.72 (m, 7.31–7.29 (m, 1 H, Ar-H), 7.16–7.08 (m, 3 H, Ar-H), 6.86 (d, J = 8.8 Hz,
2 H, CH2), 2.17–2.08 (m, 1 H, CH2), 1.78–1.69 (m, 1 H, CH2), 1.25 (d,
J = 6.8 Hz, 3 H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 202.4 (s,
C=O), 140.9 (s, Ar-C), 139.3 (s, Ar-C), 134.7 (s, Ar-C), 132.8 (d, Ar-CH),
130.4 (d, Ar-CH), 129.7 (d, 2 C, Ar-CH), 128.9 (d, 2 C, Ar-CH), 127.8
(d, Ar-CH), 127.5 (d, Ar-CH), 124.4 (s, Ar-C), 40.1 (d, CH), 33.8 (t, CH2),
33.4 (t, CH2), 17.2 (q, CH3) ppm. HRMS (ESI+): calcd. for C17H17BrClO
[M + H]+ 351.0146; found 351.0151.
1 H, Ar-H), 3.93 (s, 3 H, Ar-OCH3), 3.91 (s, 3 H, Ar-OCH3), 3.49–3.44
(m, 1 H, CH), 2.76–2.72 (m, 2 H, CH2), 2.18–2.09 (m, 1 H, CH2), 1.78–
1.71 (m, 1 H, CH2), 1.24 (d, J = 6.8 Hz, 3 H, CH3) ppm. 13C NMR
(CDCl3, 100 MHz): δ = 202.4 (s, C=O), 153.1 (s, Ar-C), 149.0 (s, Ar-C),
139.4 (s, Ar-C), 133.8 (s, Ar-C), 130.5 (d, Ar-CH), 129.6 (s, Ar-C), 129.4
(d, Ar-CH), 127.4 (d, Ar-CH), 126.7 (d, Ar-CH), 122.6 (d, Ar-CH), 110.5
(d, Ar-CH), 109.9 (d, Ar-CH), 56.0 (q, Ar-OCH3), 55.9 (q, Ar-OCH3), 39.5
(d, CH), 33.6 (t, CH2), 31.3 (t, CH2), 17.6 (q, CH3) ppm. HRMS (ESI+):
calcd. for C19H22ClO3 [M + H]+ 333.1252; found 333.1261.
4-(2-Chlorophenyl)-1-(4-methoxyphenyl)-2-methylbutan-1-one
(3ib): GP-2 was performed with allylic alcohol 1i (123.0 mg,
0.75 mmol) and alkene 2b (113.8 mg,0.825 mmol) in the presence
of KOtBu (126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the
reaction mixture was stirred at 80 °C for 8 h. Purification of the
crude material by silica gel column chromatography (petroleum
4-(2-Bromophenyl)-1-(3,4-dimethoxyphenyl)-2-methylbutan-1-
one (3jc): GP-2 was performed with allylic alcohol 1j (145.5 mg,
0.75 mmol) and alkene 2c (150.0 mg,0.825 mmol) in the presence
of KOtBu (126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the
ether/ethyl acetate, 90:10 to 95:05) furnished product 3ib reaction mixture was stirred at 80 °C for 8 h. Purification of the
(126.8 mg, 56 %) as a colourless viscous liquid [TLC control (petro- crude material by silica gel column chromatography (petroleum
leum ether/ethyl acetate, 90:10), Rf(1i) = 0.20, Rf(3ib) = 0.70, UV
ether/ethyl acetate, 80:20 to 85:15) furnished product 3jc (155.1 mg,
55 %) as a colourless viscous liquid [TLC control (petroleum ether/
detection]. IR (MIR-ATR, 4000–600 cm–1): νmax = 2965, 2930, 1719,
˜
1686, 1599, 1450, 1287, 1089, 934, 718 cm–1
.
1H NMR (CDCl3, ethyl acetate, 80:20), Rf(1j) = 0.20, Rf(3jc) = 0.60, UV detection]. IR
400 MHz): δ = 7.90 (d, J = 8.8 Hz, 2 H, Ar-H), 7.32–7.30 (m, 1 H, Ar-
H), 7.17–7.10 (m, 3 H, Ar-H), 6.92 (d, J = 8.8 Hz, 2 H, Ar-H), 3.86 (s,
3 H, Ar-OCH3), 3.49–3.41 (m, 1 H, CH), 2.78–2.70 (m, 2 H, CH2), 2.18–
2.09 (m, 1 H, CH2), 1.78–1.69 (m, 1 H, CH2), 1.24 (d, J = 6.8 Hz, 3 H,
CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 202.3 (s, C=O), 163.3 (s,
Ar-C), 139.5 (s, Ar-C), 133.9 (s, Ar-C), 130.5 (d, 2 C, Ar-CH), 130.5 (d,
Ar-CH), 129.4 (d, Ar-CH), 129.4 (s, Ar-C), 127.4 (d, Ar-CH), 126.7 (d,
Ar-CH), 113.7 (d, 2 C, Ar-CH), 55.4 (q, Ar-OCH3), 39.7 (d, CH), 33.5 (t,
CH2), 31.3 (t, CH2), 17.5 (q, CH3) ppm. HRMS (ESI+): calcd. for
C18H20ClO2 [M + H]+ 303.1146; found 303.1141.
(MIR-ATR, 4000–600 cm–1): νmax = 2962, 2923, 2852, 1736, 1598,
˜
1567, 1502, 1460, 1247, 1162, 942, 760, 700 cm–1 1H NMR (CDCl3,
.
400 MHz): δ = 7.54–7.48 (m, 3 H, Ar-H), 7.21–7.14 (m, 2 H, Ar-H),
7.05–7.01 (m, 1 H, Ar-H), 6.86 (d, J = 8.3 Hz, 1 H, Ar-H), 3.94 (s, 3 H,
Ar-OCH3), 3.91 (s, 3 H, Ar-OCH3), 3.52–3.43 (m, 1 H, CH), 2.77–2.73
(m, 2 H, CH2), 2.17–2.10 (m, 1 H, CH2), 1.78–1.71 (m, 1 H, CH2), 1.25
(d, J = 6.8 Hz, 3 H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 202.4
(s, C=O), 153.1 (s, Ar-C), 149.0 (s, Ar-C), 141.1 (s, Ar-C), 132.7
(d, Ar-CH), 130.4 (d, Ar-CH), 129.5 (s, Ar-C), 127.6 (d, Ar-CH), 127.4
(d, Ar-CH), 124.3 (s, Ar-C), 122.7 (d, Ar-CH), 110.5 (d, Ar-CH), 109.9
(d, Ar-CH), 56.0 (q, Ar-OCH3), 55.9 (q, Ar-OCH3), 39.5 (d, CH), 33.9
(t, CH2), 33.7 (t, CH2), 17.6 (q, CH3) ppm. HRMS (ESI+): calcd. for
1-(3,4-Dimethoxyphenyl)-2-methyl-4-phenylbutan-1-one (3ja):
GP-2 was performed with allylic alcohol 1j (145.5 mg, 0.75 mmol)
and alkene 2a (104.0 mg,0.825 mmol) in the presence of KOtBu
C
19H21BrNaO3 [M + Na]+ 399.0566; found 399.0577.
(126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the reaction mix- 1-(3,4-Dimethoxyphenyl)-2-methyl-4-(o-tolyl)butan-1-one (3je):
ture was stirred at 80 °C for 8 h. Purification of the crude material GP-2 was performed with allylic alcohol 1j (145.5 mg, 0.75 mmol)
by silica gel column chromatography (petroleum ether/ethyl acet- and alkene 2e (97.3 mg,0.825 mmol) in the presence of KOtBu
ate, 80:20 to 85:15) furnished product 3ja (127.3 mg, 57 %) as a (126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the reaction mix-
colourless viscous liquid [TLC control (petroleum ether/ethyl acet- ture was stirred at 80 °C for 8 h. Purification of the crude material
ate, 80:20), Rf(1j) = 0.20, Rf(3ja) = 0.70, UV detection]. IR (MIR-ATR, by silica gel column chromatography (petroleum ether/ethyl acet-
4000–600 cm–1): νmax = 2958, 2921, 2851, 1671, 1585, 1514, 1461, ate, 80:20 to 85:15) furnished product 3je (121.6 mg, 52 %) as a
˜
1262, 1150, 1024, 752 cm–1
.
1H NMR (CDCl3, 400 MHz): δ = 7.49–
colourless viscous liquid [TLC control (petroleum ether/ethyl acet-
7.44 (m, 2 H, Ar-H), 7.29–7.25 (m, 2 H, Ar-H), 7.20–7.14 (m, 3 H, Ar-
H), 6.85 (d, J = 8.3 Hz, 1 H, Ar-H), 3.94 (s, 3 H, Ar-OCH3), 3.90 (s, 3
H, Ar-OCH3), 3.48–3.40 (m, 1 H, CH), 2.66–2.61 (m, 2 H, CH2), 2.19–
2.12 (m, 1 H, CH2), 1.79–1.71 (m, 1 H, CH2), 1.22 (d, J = 6.8 Hz, 3 H,
CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 202.8 (s, C=O), 153.1 (s,
Ar-C), 149.0 (s, Ar-C), 141.8 (s, Ar-C), 129.6 (s, Ar-C), 128.5 (d, 2 C,
Ar-CH), 128.3 (d, 2 C, Ar-CH), 125.9 (d, Ar-CH), 122.6 (d, Ar-CH), 110.4
(d, Ar-CH), 109.9 (d, Ar-CH), 56.0 (q, Ar-OCH3), 55.9 (q, Ar-OCH3), 39.0
(d, CH), 35.4 (t, CH2), 33.5 (t, CH2), 17.6 (q, CH3) ppm. HRMS (ESI+):
calcd. for C19H23O3 [M + H]+ 299.1642; found 299.1651.
ate, 80:20), Rf(1j) = 0.20, Rf(3je) = 0.60, UV detection]. IR (MIR-ATR,
4000–600 cm–1): νmax = 2960, 2933, 2862, 1735, 1601, 1568, 1512,
˜
1465, 1249, 1158, 947, 762, 706 cm–1
.
1H NMR (CDCl3, 400 MHz):
δ = 7.951 (s, 2 H, Ar-H), 7.12–7.07 (m, 3 H, Ar-H), 6.86 (d, J = 8.8 Hz,
2 H, Ar-H), 3.94 (s, 3 H, Ar-OCH3), 3.91 (s, 3 H, Ar-OCH3), 3.51–3.46
(m, 1 H, CH), 2.63–2.58 (m, 2 H, CH2), 2.26 (s, 3 H, Ar-CH3), 2.16–2.07
(m, 1 H, CH2), 1.72–1.65 (m, 1 H, CH2), 1.24 (d, J = 6.8 Hz, 3 H, CH3)
ppm. 13C NMR (CDCl3, 100 MHz): δ = 202.6 (s, C=O), 153.1 (s, Ar-C),
149.1 (s, Ar-C), 140.0 (s, Ar-C), 135.9 (s, Ar-C), 130.2 (d, Ar-CH), 129.7
(s, Ar-C), 128.9 (d, Ar-CH), 126.0 (d, Ar-CH), 125.9 (d, Ar-CH), 122.6
(d, Ar-CH), 110.4 (d, Ar-CH), 109.9 (d, Ar-CH), 56.0 (q, Ar-OCH3), 55.9
(q, Ar-OCH3), 39.6 (d, CH), 34.2 (t, CH2), 31.0 (t, CH2), 19.2 (q, Ar-
CH3), 17.7 (q, CH3) ppm. HRMS (ESI+): calcd. for C20H25O3 [M + H]+
313.1798; found 313.1806.
4-(2-Chlorophenyl)-1-(3,4-dimethoxyphenyl)-2-methylbutan-1-
one (3jb): GP-2 was performed with allylic alcohol 1j (145.5 mg,
0.75 mmol) and alkene 2b (150.0 mg,0.825 mmol) in the presence
of KOtBu (126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the
reaction mixture was stirred at 80 °C for 8 h. Purification of the
crude material by silica gel column chromatography (petroleum
ether/ethyl acetate, 80:20 to 85:15) furnished product 3jb
1-(Benzo[d][1,3]dioxol-5-yl)-4-(2-bromophenyl)-2-methylbutan-
1-one (3kc): GP-2 was performed with allylic alcohol 1k (133.5 mg,
0.75 mmol) and alkene 2c (150.0 mg,0.825 mmol) in the presence
(144.4 mg, 58 %) as a colourless viscous liquid [TLC control (petro- of KOtBu (126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the
leum ether/ethyl acetate, 80:20), Rf(1j) = 0.20, Rf(3jb) = 0.60, reaction mixture was stirred at 80 °C for 8 h. Purification of the
UV detection]. IR (MIR-ATR, 4000–600 cm–1): νmax = 2968, 2933, crude material by silica gel column chromatography (petroleum
˜
Eur. J. Org. Chem. 2017, 3886–3895
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3893
© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
ether/ethyl acetate, 80:20 to 85:15) furnished product 3kc
by silica gel column chromatography (petroleum ether/ethyl acet-
(167.4 mg, 62 %) as a colourless viscous liquid [TLC control (petro- ate, 97:03 to 95:05) furnished product 3nd (151.0 mg, 58 %) as a
leum ether/ethyl acetate, 85:15), Rf(1k) = 0.20, Rf(3kc) = 0.70, UV
colourless viscous liquid [TLC control (petroleum ether/ethyl acet-
detection]. IR (MIR-ATR, 4000–600 cm–1): νmax = 2945, 2925, 2846,
ate, 90:10), Rf(1n) = 0.20, Rf(3nd) = 0.90, UV detection]. IR (MIR-ATR,
˜
1672, 1612, 1454, 1371, 1220, 1151, 970, 759, 682 cm–1
.
1H NMR
4000–600 cm–1): νmax = 2940, 2933, 2847, 1901, 1710, 1640, 1453,
˜
(CDCl3, 400 MHz): δ = 7.50 (d, J = 8.3 Hz, 2 H, Ar-H), 7.41 (d, J =
1.9 Hz, 1 H, Ar-H), 7.19–7.14 (m, 2 H, Ar-H), 7.05–7.01 (m, 1 H, Ar-
H), 6.82 (d, J = 8.3 Hz, 1 H, Ar-H), 6.02 (s, 2 H, Ar-OCH2), 3.43–3.38
1376, 1220, 1150, 904, 755 cm–1
.
1H NMR (CDCl3, 400 MHz): δ =
7.80 (d, J = 8.3 Hz, 2 H, Ar-H), 7.35 (d, J = 8.3 Hz, 2 H, Ar-H), 7.25 (d,
J = 8.3 Hz, 2 H, Ar-H), 6.98 (d, J = 8.3 Hz, 2 H, Ar-H), 3.38–3.31 (m,
(m, 1 H, CH), 2.78–2.70 (m, 2 H, CH2), 2.18–2.08 (m, 1 H, CH2), 1.77– 1 H, CH), 2.58–2.44 (m, 2 H, CH2), 2.41 (s, 3 H, Ar-CH3), 2.16–2.08 (m,
1.68 (m, 1 H, CH2), 1.24 (d, J = 6.8 Hz, 3 H, CH3) ppm. 13C NMR
(CDCl3, 100 MHz): δ = 201.8 (s, C=O), 151.6 (s, Ar-C), 148.2 (s, Ar-C),
141.1 (s, Ar-C), 132.8 (d, Ar-CH), 131.2 (s, Ar-C), 130.4 (d, Ar-CH),
127.6 (d, Ar-CH), 127.4 (d, Ar-CH), 124.3 (d, Ar-CH), 108.2 (d, Ar-CH),
107.8 (d, Ar-CH), 101.8 (d, Ar-OCH2), 39.8 (d, CH), 33.9 (t, CH2), 33.7
(t, CH2), 17.5 (q, CH3) ppm. HRMS (ESI+): calcd. for C18H18BrO3 [M +
H]+ 361.0434; found 361.0443.
1 H, CH2), 1.82–1.73 (m, 2 H, CH2), 1.60–1.54 (m, 1 H, CH2), 0.86 (t,
J = 7.3 Hz, 3 H, CH3) ppm. 13C NMR (CDCl3, 100 MHz): δ = 203.5 (s,
C=O), 143.8 (s, Ar-C), 140.9 (s, Ar-C), 134.9 (s, Ar-C), 131.3 (d, 2 C,
Ar-CH), 130.2 (d, 2 C, Ar-CH), 129.3 (d, 2 C, Ar-CH), 128.3 (d, 2 C, Ar-
CH), 119.5 (s, Ar-C), 46.4 (d, CH), 33.2 (t, CH2), 33.1 (t, CH2), 25.7 (t,
CH2), 21.6 (q, CH3), 11.8 (q, CH3) ppm. HRMS (ESI+): calcd. for
C
19H22BrO [M + H]+ 345.0849; found 345.0848.
4-(2-Bromophenyl)-2-methyl-1-(3,4,5-trimethoxyphenyl)butan-
1-one (3lc): GP-2 was performed with allylic alcohol 1l (168.0 mg, Acknowledgments
0.75 mmol) and alkene 2c (150.0 mg,0.825 mmol) in the presence
We are grateful to the Department of Science and Technology-
of KOtBu (126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the
reaction mixture was stirred at 80 °C for 8 h. Purification of the
crude material by silica gel column chromatography (petroleum
ether/ethyl acetate, 70:20 to 80:20) furnished product 3lc (185.7 mg,
61 %) as a colourless viscous liquid [TLC control (petroleum ether/
ethyl acetate, 70:30), Rf(1l) = 0.20, Rf(3lc) = 0.70, UV detection]. IR
Science and Engineering Research Board (DST-SERB), New Delhi
(no. SB/S1/OC-39/2014) for the financial support. S. B. thanks
the Ministry of Human Resource Development (MHRD) for the
award of a research fellowship.
(MIR-ATR, 4000–600 cm–1): νmax = 2947, 2923, 2846, 1669, 1612,
˜
Keywords: Isomerization · Allylic compounds · Ketones ·
Domino reactions · Hydrogen transfer
1454, 1371, 1220, 1152, 900, 750 cm–1
.
1H NMR (CDCl3, 400 MHz):
δ = 7.50 (d, J = 7.8 Hz, 1 H, Ar-H), 7.21–7.16 (m, 4 H, Ar-H), 7.06–
7.01 (m, 1 H, Ar-H), 3.91 (s, 3 H, Ar-OCH3), 3.88 (s, 6 H, 2×Ar-OCH3),
3.47–3.42 (m, 1 H, CH), 2.79–2.75 (m, 2 H, CH2), 2.19–2.10 (m, 1 H,
CH2), 1.79–1.72 (m, 1 H, CH2), 1.26 (d, J = 6.8 Hz, 3 H, CH3) ppm.
13C NMR (CDCl3, 100 MHz): δ = 202.6 (s, C=O), 153.1 (s, 2 C, Ar-C),
142.4 (s, Ar-C), 141.1 (s, Ar-C), 132.8 (d, Ar-CH), 131.7 (s, Ar-C), 130.5
(d, Ar-CH), 127.7 (d, Ar-CH), 127.5 (d, Ar-CH), 124.4 (s, Ar-C), 105.7
(d, 2 C, Ar-CH), 60.9 (q, Ar-OCH3), 56.3 (q, 2 C, Ar-OCH3), 39.6 (d,
CH), 33.8 (t, CH2), 33.7 (t, CH2), 17.4 (q, CH3) ppm. HRMS (ESI+): calcd.
for C20H24BrO4 [M + H]+ 407.0852; found 407.0856.
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2-Ethyl-4-phenyl-1-(p-tolyl)butan-1-one (3na): GP-2 was per-
formed with allylic alcohol 1n (121.6 mg, 0.75 mmol) and alkene
2a (150.0 mg,0.825 mmol) in the presence of KOtBu (126.0 mg,
1.125 mmol) in dry THF (1.5 mL), and the reaction mixture was
stirred at 80 °C for 12 h. Purification of the crude material by silica
gel column chromatography (petroleum ether/ethyl acetate, 97:03
to 95:05) furnished product 3na (119.0 mg, 60 %) as a colourless
viscous liquid [TLC control (petroleum ether/ethyl acetate, 90:10),
Rf(1n) = 0.20, Rf(3na) = 0.90, UV detection]. IR (MIR-ATR, 4000–
600 cm–1): νmax = 2942, 2920, 2846, 1705, 1668, 1619, 1554, 1377,
˜
1
1226, 1159, 910, 850 cm–1. H NMR (CDCl3, 400 MHz): δ = 7.80 (d,
J = 7.8 Hz, 2 H, Ar-H), 7.27–7.15 (m, 5 H, Ar-H), 7.12 (d, J = 7.8 Hz,
2 H, Ar-H), 3.39–3.33 (m, 1 H, CH), 2.65–2.49 (m, 2 H, CH2), 2.41 (s,
3 H, Ar-CH3), 2.17–2.08 (m, 1 H, CH2), 1.83–1.75 (m, 2 H, CH2), 1.62–
1.56 (m, 1 H, CH2), 0.86 (t, J = 7.5 Hz, 3 H, CH3) ppm. 13C NMR
(CDCl3, 100 MHz): δ = 203.8 (s, C=O), 143.7 (s, Ar-C), 141.9 (s, Ar-C),
136.0 (s, Ar-C), 129.3 (d, 2 C, Ar-CH), 128.4 (d, 2 C, Ar-CH), 128.3 (d,
2 C, Ar-CH), 128.3 (d, 2 C, Ar-CH), 125.8 (d, Ar-CH), 46.5 (d, CH), 33.6
(t, CH2), 33.4 (t, CH2), 25.5 (t, CH2), 21.6 (q, CH3), 11.8 (q, CH3) ppm.
HRMS (ESI+): calcd. for C19H23O [M + H]+ 267.1743; found 267.1745.
4-(4-Bromophenyl)-2-ethyl-1-(p-tolyl)butan-1-one (3nd): GP-2
was performed with allylic alcohol 1n (121.6 mg, 0.75 mmol) and
alkene 2d (150.0 mg,0.825 mmol) in the presence of KOtBu
(126.0 mg, 1.125 mmol) in dry THF (1.5 mL), and the reaction mix-
ture was stirred at 80 °C for 8 h. Purification of the crude material
Eur. J. Org. Chem. 2017, 3886–3895
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© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
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Received: March 29, 2017
Eur. J. Org. Chem. 2017, 3886–3895
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