Metal free chemoselective reduction of α-keto amides using TBAF as catalyst

Article abstract of DOI:10.1039/c4ra13090a

The metal and ligand free chemoselective reduction of the keto group and complete reduction of the both keto and amide groups of α-keto amide with hydrosilanes using tetrabutylammoniumflouride (TBAF) as catalyst have been accomplished. This methodology affords an efficient and economic route for the synthesis of biologically important α-hydroxy amides and β-amino alcohols. The other important advantage of this TBAF catalyst is chemoselective reduction of ketones to corresponding alcohols in the presence of several other sensitive functional groups.

Full text of DOI:10.1039/c4ra13090a

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Metal free chemoselective reduction of αꢀketo amides
using TBAF as catalyst
Cite this: DOI: 10.1039/x0xx00000x
N. Chary Mamillapalli and Govindasamy Sekar*
Metal and ligand free chemoselective reduction of keto group and complete reduction of the
both keto and amide groups of αꢀketo amide with hydrosilanes using
tetrabutylammoniumflouride (TBAF) as catalyst have been accomplished. This methodology
affords an efficient and economic route for the synthesis of biologically important αꢀ
hydroxy amides and βꢀamino alcohols. The other important advantage of this TBAF catalyst
is chemoselective reduction of ketones to corresponding alcohols in the presence several
other sensitive functional groups.
Received 00th January 2012,
Accepted 00th January 2012
DOI: 10.1039/x0xx00000x
www.rsc.org/
Recently, reduction of aliphatic tertiary amides to amines using
Cs2CO3 catalyst and reduction of tertiary, secondary and
Introduction
primary amides by B(C6F5)3 catalyst have been reported.13 Very
recently, we have developed a chemoselective reduction of αꢀ
ketoamides using nickel catalyst.14 As part of our onꢀgoing
research towards developing metal free synthetic reactions and
environmentally benign reaction conditions,15 herein, we report,
metal and ligand free chemoselective reduction of keto group of
αꢀketo amides and complete reduction of both keto and amide
groups of αꢀketo amide using TBAF as catalyst yielding
biologically active αꢀhyroxy amides16 and βꢀamino alcohols17
respectively at room temperature (Scheme 1). Fluoride ion was
previously been known as catalysts for the reduction of simple
aldehydes, ketones and nitriles.7e However, to the best our
knowledge, this is the first metal free fluoride ions catalyst for
the selective reduction of αꢀketo amides using hydrosilanes.
Chemoselective reduction is one of the most significant
transformations in synthetic chemistry.1 Metal catalyzed
reduction of ketone2 and amide3 functional groups using
hydrosilanes as reducing reagent are well established
transformations in synthetic methodology. The main drawback
associated with these reduction reactions is the use of expensive
metals, which require inert atmosphere and ligands. It is
believed that these reduction reactions generally take place
through metal hydride transfer.4 With the aid of acid,5 base6 or
fluoride ions,7 the hydrosilanes paved route for metal free
reduction of ketones. There has been tremendous growth in the
base catalyzed reduction of ester8 and tertiary amide9 functional
groups. The serious limitation of this base catalyzed reduction
is moderate selectivity and works only with tertiary amides.
However, recently, much attention has been focused on the
metal free reduction of secondary amides. Recently, Beller et
al. reported metal free selective monoreduction of phthalimides
Results and discussion
and imidazolidineꢀ2,4ꢀdiones using TBAF catalyst10 and The optimization of the chemoselective reduction was initiated
selective reduction of tertiary amide to amine with boronic acid with 2ꢀoxoꢀNꢀ2ꢀdiphenylacetamide 1a as model substrate, using
catalyst.11 Charette et al. reported metal free chemoselective polymethylhydrosilane (PMHS) as reducing agent with 5 mol%
reduction of secondary amides to amines using triflic anhydride of TBAF catalyst at room temperature in THF. This reaction
and Et3SiH/Hantzsch ester hydride (HEH).12
yielded 60% of chemoselectively reduced product αꢀhydroxy
amide 2a in 24 hours (Table 1, entry 1). Usage of 10 mol% of
TBAF catalyst drastically increased the reactivity but the
selectivity got reduced as it yielded 86% of 2a along with 10%
of βꢀamino alcohol 3a (entry 2). In order to increase the
chemoselectivity, various hydrosilanes were examined and the
results are summarized in Table 1. Alkoxysilanehydrides such
as (EtO)3SiH and Me(EtO)2SiH produced 3a as major product
with 55% and 50% yield respectively (entries 3 and 4).
Scheme 1: Reduction of αꢀketoamide using TBAF catalyst
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Table 1. Reduction of αꢀketo amide by various hydrosilanes with 2a as minor product (Table 1, entry 10). Using Ph2SiH2 as
using TBAF catalysta
hydride transfer agent offered almost exclusive formation of 3a
in 4 hours (Table 1, entry 11). Other hydride transfer agents
such as PMHS, (EtO)3SiH, Me(EtO)2SiH and TMDS also
provided 3a in good yield, however the reaction time was too
long (entries 12 to 15). Other fluoride sources such as CsF and
KF were failed to yield 3a. To know the role of TBAF in the
reduction reactions, blank reactions were carried out only with
hydrosilanes without TBAF but the reduction reaction did not
take place at all (Table 1, entries 16 and 17).
Table 2. Chemoselective reduction of αꢀketo amide by TBAF
catalysta
Alkylsilanehydride such as (Et)3SiH, Me2ClSiH and MeCl2SiH
are slow in reduction reaction but provided only chemoselective
reduced product 2a with poor yields 29%, 19% and 15%
respectively after 24 hours (entries 5ꢀ7). Surprisingly, in the
presence of 3 equivalents of Ph3SiH, the reaction yielded 97%
of exclusively 2a after 6 hours and not even trace amount of
complete reduced product 3a was observed (entry 9).
Increasing the amount of Ph3SiH to 10 equivalents and reaction
time 48 hours also did not affect the chemoselectivity. These
results show that the bulkiness and reactivity of Ph3SiH is
playing a major role in the selective reduction of keto group of
1a. In presence of (EtO)3SiH, Me(EtO)2SiH, tetramethyl
disiloxane (TMDSO) and Ph2SiH2 (entries 3, 4, 10 and 11), the
selectivity was reduced due to the high reactivity and small size
of hydrosilanes. Me2ClSiH and MeCl2SiH are less reactive than
(Et)3SiH due to the presence of chlorine and selectively
provided only 2a with low yields (Table 1, entries 5 to 7).18
Using this optimized reaction condition (entry 9), several αꢀ
keto amides were chemoselectively reduced and the results are
summarized in Table 2. Substitutions like electron withdrawing
groups (2f
the aromatic ring attached to amide nitrogen and aliphatic
amide attached ketone (2i 2j and 2k) were well tolerated under
, 2l and 2m), electron donating groups (2d and 2e) on
,
our standard reaction condition. It is important to note that
other sensitive functional groups which are prone to reduction
reaction such as nitrile (2m), nitro (2l) and halo (2g) groups
were unaffected.
After the selective reduction of keto group of αꢀketo amides,
the focus was shifted to complete reduction to produce 3a. In
order to shift the reduction towards 3a, strong hydrosilanes
such as TMDSO and Ph2SiH2 were used for the reduction. As
we expected, TMDSO yielded 72% of fully reduced 3a along
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To establish the substrate scope of complete reduction, several
αꢀketo amides were treated with Ph2SiH2 in presence of TBAF
and the results are summarized in Table 3. Electron donating
groups (3c, 3d and 3e) and electron withdrawing groups (3f and
3g) did not affect the yield of the complete reduction
products.19
Table 3. Complete reduction of αꢀketo amide by TBAF
catalysta
Scheme 2. The plausible mechanism for the selective reduction
of αꢀketo amides by TBAF catalyst.
The mechanism for the TBAFꢀcatalysed complete reduction of
αꢀketoamides also should be similar to the TBAFꢀcatalysed
selective monoreduction of phthalimides.10 The penta
coordinate silicon compound
transferring the hydride to amide to give the corresponding
disilylated amine 11 (Scheme 3). Another activated hydride
9 would reduce the amide 10 by
9
may transfer the second hydride atom to 11 as shown in 12 to
form mono silylated amine 13 then subsequent base workup
should yield the complete reduced product 3a
.
The mechanism for the TBAFꢀcatalyzed selective reduction of
αꢀketoamides might be similar to the fluoride ion catalyzed
hydrosilylation of ketones.7 First, the activation of silicon atom
by anionic fluorine coordination to give penta coordinate
Scheme 3. The plausible mechanism for the complete reduction
of αꢀketoamides by TBAF catalyst.
Other amides such as phenyl benzamide, methyl benzamide and
silicon compound20
ketone by transferring the hydride to the carbonyl carbon to
6 which would then reduce selectively the
N,2ꢀdiphenyl acetamide did not react under complete reduction
condition. However, on the other hand, αꢀhydroxy amide 2a
and trimethylsilane protected hydroxy amide 15 react under
similar reaction conditions and provided the fully reduced
product in 93% and 90% respectively. In addtion, αꢀmethoxy
amide 16 did not yield even a trace amount of reduced product.
yield the corresponding silylated amide
7, which upon base
treatment would yield 2a (scheme 2).
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These results suggest that the αꢀhydroxy group of αꢀhydroxy To examine the scalability of these metalꢀfree reductions, the
amide plays a crucial role in the reduction of amide group of αꢀ selective reduction and complete reduction of 2ꢀoxoꢀ ꢀ2ꢀ
keto amide (Scheme 4). diphenylacetamide 1a was performed in a gram scale and the
N
results are summarized in Scheme 5.
Scheme 4
Scheme 5: Gram scale reaction of 1a with TBAF
Table 4. Chemoselective reduction of ketones by TBAF
catalysta
This metal free methodology affords various biologically active
αꢀhydroxy amide and βꢀamino alcohols at room temperature.
O
OH
TBAF (10 mol %), Ph3SiH (3 equiv.)
THF, rt
R1
R2
17
R1
R2
18
Conclusions
Entry
4
5
TIme (h)
Yieldb (%)
In conclusion, we have developed an efficient transition metal
and ligand free TBAF catalysed chemoselective and complete
reduction of αꢀketo amides using appropriate hydrosilanes at
room temperature. The present metalꢀfree reduction method
have several advantages including short reaction times, high
yields, reaction at room temperature, chemoselective and
complete reductions using appropriate hydrosilanes. The
important advantage of using TBAF catalyst is chemoselective
reduction of ketones to corresponding alcohols in the presence
several other sensitive functional groups.
O
OH
O
O
1
5
97
O
O
17a
18a
O
OH
OH
2
3
4
6
6
6
90
94
95
NC
NC
17b
17c
18b
18c
O
O
O2N
O2N
OH
Experimental Section
O2N
O2N
General Considerations
17d
17e
17f
18d
18e
18f
O
OH
Hydrosilanes and TBAF (1.0 M solution in THF) were
purchased from Sigma Aldrich chemical company. Thinꢀlayer
chromatography (TLC) was performed using Merck silica gel
60 F254 preꢀcoated plates (0.25 mm) and visualized by UV
fluorescence quenching. Silica gel for column chromatography
(particle size 100ꢀ200 mesh) was purchased from SRL India. 1H
and 13C NMR spectra were recorded on a Bruker 400 MHz
5
6
7
5
6
6
92
95
87
O
OH
O
OH
1
instrument. H NMR spectra were reported relative to residual
CHCl3 (
reported relative to CDCl3 (
δ
7.26 ppm) or DMSOꢀd6 (
77.16 ppm) or DMSOꢀd6 (δ 39.52
δ
2.50 ppm). 13C NMR were
17g
18g
OH
O
δ
8
5
89
ppm). FTIR spectra were recorded on a JASCO spectrometer
and are reported in frequency of absorption (cmꢀ1). High
resolution mass spectra (HRMS) were recorded on QꢀTof
Micro mass spectrometer.
18h
17h
aReaction condition: 0.5 mmol of 17 in THF. bIsolated yield
We further extended the scope of this chemoselective reduction
reaction to simple ketones in the presence of several other
sensitive functional groups and the results are summarized in
Table 4. Various functional groups such as olefin, nitro, nitrile
and ester tolerable under the catalytic system.
General experimental procedure for synthesis of αꢀketo
amides
Thionyl chloride (0.3 mL, 4 mmol) was added drop wise to a
stirred mixture of benzyl formic acid (0.300 g, 2 mmol) and
Et3N (0.5 mL, 4 mmol) in CH2Cl2 (10 mL) at 0 oC under
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nitrogen atmosphere. The stirring was continued for 20 min.
and then a suspension of corresponding amine (2 mmol) in NMR (100 MHz, CDCl3):
J
= 7.2 Hz, 1H), 5.15 (d,
J
δ
= 2.0 Hz, 1H), 3.57 (bs, 1H); 13C
170.1, 139.1, 137.2, 129.2, 129.2,
CH2Cl2 (10 mL) was added slowly to the reaction mixture at 0 129.1, 129.0, 127.0, 119.9, 74.8; IR (KBr) 3232, 1666, 1660,
oC under nitrogen flow. The stirring was continued in the room 1651, 1600, 1066 cm−1; HRMS ( ): [M+Na]+ calcd for
m/z
temperature and the completion of the reaction was monitored C14H13NO2Na1, 250.0844; found, 250.0846.
by TLC. A saturated aqueous solution of NaHCO3 (20 mL) was
slowly added to the reaction mixture. The organic layer was 2ꢀHydroxyꢀNꢀphenylbutanamide (2b):
o
o
separated, washed with water (3 × 15 mL) and evaporated Colorless solid, mp = 129ꢀ130 C (lit.14 mp = 129ꢀ130 C); Rf
1
under reduced pressure. The solid residue was purified by silica 0.30; (hexanes : ethyl acetate, 80:20 v/v): H NMR (400 MHz,
gel column chromatography.
CDCl3):
δ
8.42 (bs, 1H), 7.56 (dd,
= 8.4 Hz, 1H), 4.24ꢀ4.18 (m, 1H),
= 4.8 Hz, 1H), 2.03ꢀ1.91 (m, 1H), 1.86ꢀ1.74 (m, 1H),
= 7.6 Hz, 3H); 13C NMR (100 MHz, CDCl3):
171.8,
J = 8.6, 1.2 Hz, 2H), 7.33 (t,
J
=7.6 Hz, 2H), 7.12 (t,
J
General experimental procedure for chemoselective
reduction of αꢀketo amides using TBAF catalyst
2.81 (d,
1.03 (t,
J
J
δ
A mixture of TBAF (1M solution in THF, 50 µL, 0.05 mmol) 137.3, 129.2, 124.7, 119.9, 73.7, 28.0, 9.3; IR (KBr) 3400,
and αꢀketo amide (0.5 mmol) in 1.5 mL of distilled THF was 1646, 1600, 1528, 1443, 1119 cm−1; HRMS (
taken in a reaction tube. The reaction mixture was stirred at calcd for C10H14NO2, 180.1025; found, 180.1031.
room temperature for 10 min. Then Ph3SiH (390 mg, 1.5 mmol)
m/z
): [M+H]+
was added to the reaction mixture. After that, the resulting 2ꢀHydroxyꢀ2ꢀ(4ꢀmethoxyphenyl)ꢀNꢀphenylacetamide (2c):
o
o
reaction mixture was stirred at room temperature under open Colorless solid, mp = 94ꢀ95 C (lit.14 mp = 94ꢀ95 C); Rf 0.32;
air. The progress of the reaction was monitored by TLC. After (hexanes : ethyl acetate, 80:20 v/v): 1H NMR (400 MHz,
complete disappearance of substrate, 10 mL of 2N aq. NaOH CDCl3):
was added to the reaction and the resulting mixture was stirred 8.4 Hz, 2H), 7.31(t, J = 7.6 Hz, 2H), 7.12 (t,
for 10 min. The reaction mixture was extracted with ethyl 6.90 (d, J = 8.4 Hz, 2H), 5.11 ( s. 1H), 3.80 (s, 3H), 13C NMR
acetate (2x10 mL). The combined organic layers were washed (100 MHz, CDCl3): 170.4, 160.2, 137.2, 131.3, 129.2, 128.5
with brine, dried over anhydrous MgSO4, filtered off and the 124.8, 119.9, 114.5, 74.4, 55.5; IR (KBr) 3271, 1644, 1594,
solvent was removed under reduced pressure. The resulting 1532, 1442, 1065 cm−1; HRMS ( ): [M+H]+ calcd for
δ
8.17 (bs, 1H), 7.52 (d, J = 7.6 Hz, 2H), 7.37 (d,
J =
J
= 7.2 Hz, 1H),
δ
m/z
residue was purified by silica gel column chromatography C15H16NO3, 258.1130; found, 258.1133.
(eluents: hexanesꢀethyl acetate, 80:20) to obtain pure αꢀhydrxoy
amide.
2ꢀHydroxyꢀ2ꢀphenylꢀ
Nꢀ(oꢀtolyl)acetamide (2d):
o
Colorless solid, mp = 85ꢀ86 C; Rf 0.36; (hexanes : ethyl
General experimental procedure for complete reduction of
αꢀketo amides using TBAF catalyst
1
acetate, 80:20 v/v): H NMR (400 MHz, CDCl3):
1H), 7.82 (d, = 8.4 Hz, 1H), 7.44 (dd, = 7.6, 2.0 Hz, 2H),
= 6.4,1.2 Hz,
δ 8.20 (bs,
J
J
A mixture of TBAF (1M solution in THF, 50 µL, 0.05 mmol) 7.32ꢀ7.39 (m, 3H), 7.13ꢀ7.19 (m, 2H), 7.06 (td,
and αꢀketo amide (0.5 mmol) in 1.5 mL of dry THF was taken 1H), 5.08 (s, 1H), 4.16 (s, 1H), 2.13 (s, 3H); 13C NMR (100
J
o
in a reaction tube at 0 C. The reaction mixture was stirred at 0 MHz, CDCl3):
δ 170.6, 139.3, 135.3, 135.0,130.6, 128.8 127.8,
oC temperature for 10 min. Then Ph2SiH2 (370 µL, 2 mmol) 126.9, 126.8, 125.4, 122.3, 74.7, 17.5; IR (KBr) 3319, 1668,
was slowly added drop wise to the reaction mixture at 0 C 1588, 1532, 1493, 1064 cm−1; HRMS (
m
/z
): [M+H]+ calcd for
o
under nitrogen atmosphere. After that, the reaction tube was C15H16 NO2, 242.1181; found, 242.1180.
closed with glass stopper under nitrogen flow and the resulting
reaction mixture was stirred at room temperature. The progress 2ꢀHydroxyꢀNꢀ(3ꢀmethoxyphenyl)ꢀ2ꢀphenylacetamide (2e):
o
of the reaction was monitored by TLC. After complete Colorless solid, mp = 132ꢀ133 C; Rf 0.31; (hexanes : ethyl
1
disappearance of substrate, 5 mL of 2N aq. NaOH was added to acetate, 80:20 v/v): H NMR (400 MHz, CDCl3):
δ
9.87 (bs,
= 1.6 Hz, 1H), 7.35(t,
The reaction mixture was extracted with ethyl acetate (2x10 = 6.8 Hz, 2H), 7.26ꢀ7.31 (m, 2H), 7.18 (t, = 8.0 Hz, 1H), 6.62
mL). The combined organic layers were washed with brine, (dd, = 8.2, 1.6 Hz, 1H), 6.42 (d, = 4.8 Hz, 1H), 5.08 (d,
dried over anhydrous MgSO4, filtered off and the solvent was 4.4 Hz, 1H), 3.70 (s, 3H); 13C NMR (100 MHz, CDCl3):
the reaction and the resulting mixture was stirred for 10 min. 1H), 7.50 (d,
J
= 7.2 Hz 2H), 7.40 (t,
J
J
J
J
J
J
=
δ
removed under reduced pressure. The resulting residue was 171.2, 159.5, 140.8, 139.7, 129.4, 128.1, 127.6, 126.6, 111.9,
purified by neutral aluminium oxide column chromatography 109.1, 105.3, 74.0, 55.0; IR (KBr) 3409, 3327, 1654, 1607,
m/z
(eluents: hexanesꢀethyl acetate, 90:10) to obtain pure βꢀamino 1561, 1496, 1053 cm−1; HRMS ( ): [M+H]+ calcd for
alcohol.
C15H16NO3, 258.1130; found, 258.1138.
2ꢀHydroxyꢀN, 2ꢀdiphenylacetamide (2a):
2ꢀHydroxyꢀ2ꢀphenylꢀNꢀ(4ꢀ(CF3)phenylacetamide (2f):
o
o
Colourless solid, mp = 152ꢀ153 C (lit.14 mp = 152ꢀ153 C); Rf
o
Colorless solid, mp = 176ꢀ177 C; Rf 0.40; (hexanes : ethyl
1
0.56; (hexanes : ethyl acetate, 80:20 v/v): H NMR (400 MHz,
1
acetate, 80:20 v/v): H NMR (400 MHz, CDCl3):
δ
10.33 (bs,
CDCl3):
δ
8.19 (bs, 1H), 7.51 (d,
J
=7.6 Hz, 2H), 7.47 (d,
J =
1H), 7.96 (d,
J
= 8.4 Hz, 2H), 7.68 (d,
J
= 8.4 Hz, 2H), 7.54 (d,
6.8 Hz, 2H), 7.42ꢀ7.34 (m, 3H), 7.31 (t,
J
= 7.2 Hz, 2H), 7.12 (t,
J = 7.2 Hz, 2H), 7.38 (t,
J
= 7.6 Hz, 2H), 7.29ꢀ7.34 (m, 1H),
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6.55 (d,
J
= 4.4 Hz, 1H), 5.17 (d,
J
= 4.0 Hz, 1H); 13C NMR 1479, 1064 cm−1; HRMS (
m
/
z
): [M+H]+ calcd for C12H18NO2,
(100 MHz, CDCl3):
127.7, 126.6, 125.9 (q,
δ
171.9, 142.2, 140.5, 134.5, 128.1, 128.0, 208.1338; found, 208.1339.
= 3.6 Hz, CF3), 119.7, 74.1; IR (KBr)
J
3235, 1666, 1614, 1604, 1556, 1072 cm−1; HRMS (
m/z): 2ꢀHydroxyꢀNꢀ(3ꢀnitrophenyl)ꢀ2ꢀphenylacetamide (2l):
[M+Na]+ calcd for C15H12NO2F3Na1, 318.0718; found, Colorless solid, mp = 142ꢀ143 C; Rf 0.42; (hexanes : ethyl
o
1
318.0723.
acetate, 70:30 v/v): H NMR (400 MHz, CDCl3):
δ
10.50 (bs,
= 8.0 Hz, 1H), 7.92 (dd, = 8.2,
= 8.0 Hz, 1H), 7.55 (d, = 7.6 Hz, 2H),
= 7.2 Hz, 2H ), 7.32 (t, = 7.2 Hz, 1H ), 6.59 (s, 1H),
172.1, 147.9,
= 8.2, 1.6 Hz, 140.5, 139.8, 130.0, 128.2, 127.8, 126.6, 125.9, 118.1, 113.9,
= 7.8 Hz, 2H), 7.28ꢀ7.40 (m, 4H), 7.16 (td,
74.1; IR (KBr) 3213, 1659, 1620, 1603, 1550, 1067 cm−1;
7.8, 1.6 Hz, 1H) 6.94 (d, = 4.0 Hz, 1H), 5.18 (d, = 4.0 Hz, HRMS (
): [M+Na]+ calcd for C14H12N2O4Na1, 295.0695;
1H); 13C NMR (100 MHz, CDCl3):
170.8, 140.4, 134.1, found, 295.0690.
1H), 8.78 (s, 1H), 8.14 (d,
1.2 Hz, 1H), 7.60 (t,
J
J
N
ꢀ(2ꢀchlorophenyl)ꢀ2ꢀhydroxyꢀ2ꢀphenylacetamide (2g):
J
J
Colorless solid, mp = 96ꢀ97 oC; Rf 0.36; (hexanes : ethyl 7.38 (t,
J
J
1
acetate, 70:30 v/v): H NMR (400 MHz, CDCl3):
δ δ
9.64 (bs, 5.17 (s, 1H ); 13C NMR (100 MHz, CDCl3):
1H), 8.09 (dd,
1H), 7.49 (d,
J = 8.0, 1.6 Hz, 1H), 7.53 (dd, J
J
J =
J
J
m/z
δ
129.4, 128.2, 127.8, 127.8, 126.7, 125.5, 123.8, 122.2, 73.6; IR
(KBr) 3289, 1671, 1596, 1590, 1553, 1436, 1058 cm−1; HRMS Nꢀ(2ꢀcyanophenyl)ꢀ2ꢀhydroxyꢀ2ꢀphenylacetamide (2m):
o
(
m
/
z
): [M+H]+ calcd for C14H13NO2Cl, 262.0635; found, Colorless solid, mp = 128ꢀ129 C; Rf 0.37; (hexanes : ethyl
1
262.0648.
acetate, 70:30 v/v): H NMR (400 MHz, CDCl3):
δ
10.12 (bs,
1H), 7.84 (d,
7.2 Hz, 2H), 7.29ꢀ7.42 (m, 4H), 6.82 (d,
= 4.4 Hz, 1H); 13C NMR (100 MHz, CDCl3):
δ
J
= 8.0 Hz, 2H), 7.66ꢀ7.73 (m, 1H), 7.54 (d,
= 4.4 Hz, 1H), 5.20
171.4,
(hexanes : ethyl acetate, 70:30 v/v): 1H NMR (400 MHz, 140.4, 139.8, 133.9, 133.0, 128.2, 127.8, 126.8, 125.4, 123.7,
CDCl3): 7.25ꢀ7.13 (m, 3H), 7.14ꢀ7.04 (m, 3H), 6.76ꢀ 6.74 (m, 166.5, 105.8, 73.6; IR (KBr) 3311, 2234, 1687, 1601, 1577,
4H), 4.95 (s, 1H), 3.23 (s, 3H); 13C NMR (100 MHz, CDCl3): 1058 cm−1; HRMS ( ): [M+Na]+ calcd for C15H12N2O2Na1,
J =
2ꢀHydroxyꢀNꢀmethylꢀN,2ꢀdiphenylacetamide (2h):
J
o
o
Colorless solid, mp = 89ꢀ90 C (lit.14 mp = 89ꢀ90 C) ; Rf 0.40; (d,
J
δ
δ
m/z
172.9, 141.5, 139.3, 129.6, 128.4, 128.1, 128.0, 127.3, 71.7, 275.0796; found, 275.0801.
38.4; IR (KBr) 3433, 1652, 1591, 1490, 1447, 1084 cm−1;
HRMS (
242.1192.
m/z
): [M+H]+ calcd for C15H16NO2, 242.1181; found, 1ꢀPhenylꢀ2ꢀ(phenylamino)ethanol (3a):
Colourless oily liquid; Rf 0.36; (hexanes : ethyl acetate, 80:20
1
v/v): H NMR (400 MHz, CDCl3):
7.31 (m, 1H), 7.24ꢀ7.18 (m, 2H), 6.82ꢀ6.77 (m, 1H), 6.75 (dd,
Colorless solid, mp = 78ꢀ79 oC (lit.21 77 oC) ; Rf 0.55; (hexanes = 8.6, 1.2 Hz, 2H), 4.96 (dd,
= 8.6, 4.0 Hz, 1H), 3.45 (dd,
: ethyl acetate, 70:30 v/v): 1H NMR (400 MHz, CDCl3):
7.39ꢀ 13.0, 3.6 Hz, 1H), 3.32 (dd,
7.28 (m, 5H), 5.20 (s, 1H), 3.81ꢀ3.73 (m, 1H), 3.49ꢀ3.43 (m, (100 MHz, CDCl3): 147.3, 142.0, 129.5, 128.8, 128.2, 126.0,
1H), 3.17 (t, = 4.4 Hz, 2H), 1.62ꢀ1.41 (m, 5H), 1.36ꢀ1.27 (m, 119.0, 114.2, 72.4, 52.5; IR (Neat) 3402, 1708, 1600, 1503,
1H), 0.95ꢀ0.85 (m, 1H); 13C NMR (100 MHz, CDCl3): 170.5, 1055 cm−1; HRMS ( ): [M+H]+ calcd for C14H16NO,
δ 7.44ꢀ7.36 (m, 4H), 7.35ꢀ
2ꢀHydroxyꢀ2ꢀphenylꢀ1ꢀ(piperidinꢀ1ꢀyl)ethanꢀ1ꢀone (2i):
J
=
J
J
J
δ
= 13.0, 8.8 Hz, 1H); 13C NMR
δ
J
δ
m/z
139.8, 129.1, 128.5, 127.5, 71.5, 45.9, 44.1, 25.4, 25.2, 24.2; IR 214.1232; found, 214.1230.
(KBr) 3223, 1625, 1449, 1361, 1264, 1081 cm−1; HRMS (
[M+H]+ calcd for C13H18NO2, 220.1338; found, 220.1340.
m/z):
1ꢀ(Phenylamino)butanꢀ2ꢀol (3b):
Colourless oily liquid; Rf 0.40; (hexanes : ethyl acetate, 80:20
1
NꢀBenzylꢀ2ꢀhydroxyꢀ2ꢀphenylacetamide (2j):
v/v): H NMR (400 MHz, CDCl3):
δ
7.77ꢀ7.72 (m, 2H), 7.22ꢀ
= 8.4, 1.2 Hz, 2H), 3.82ꢀ3.74 (m,
= 12.8, 8.5 Hz,
= 7.2 Hz, 3H); 13C NMR (100
148.2, 129.5, 118.3, 113.6, 71.8, 50.2, 28.1,
= 3.2 Hz, 1H); 13C NMR (100 MHz, 10.1; IR (Neat) 3623, 3549, 1740, 1605, 1464, 1047 cm−1;
172.2, 139.5, 137.8, 129.0, 128.9, 127.7, 127.0, 74.4, HRMS (
): [M+H]+ calcd for C10H16NO, 166.1232; found,
43.7; IR (KBr) 3232, 1732, 1625, 1535, 1448, 1060 cm−1; 166.1228.
HRMS (
): [M+H]+ calcd for C15H16NO2, 242.1171; found,
242.1181.
o
o
Colorless solid, mp = 133ꢀ134 C (lit.14 mp = 133ꢀ134 C); Rf 7.15 (m, 2H), 6.68 (dd,
J
1
0.35; (hexanes : ethyl acetate, 80:20 v/v): H NMR (400 MHz, 1H), 3.28 (dd,
J
= 12.8, 3.2 Hz, 1H), 3.02 (dd,
1H), 1.64ꢀ1.51 (m, H), 1.02 (t,
= 2.8 Hz, 1H), 4.49ꢀ MHz, CDCl3):
J
CDCl3):
6.0, 2.0 Hz, 2H), 6.47 (bs, 1H), 5.06 (d,
4.36 (m, 2H), 3.68 (d,
CDCl3):
δ
7.42ꢀ7.32 (m, 5H),7.32ꢀ7.25 (m, 3H), 7.18 (dd,
J
=
2
J
J
δ
J
δ
m/z
m/z
1ꢀ(4ꢀMethoxyphenyl)ꢀ2ꢀ(phenylamino)ethanꢀ1ꢀol (3c):
Pale yellow oily liquid; Rf 0.37; (hexanes : ethyl acetate, 80:20
1
NꢀtertꢀButylꢀ2ꢀhydroxyꢀ2ꢀphenylacetamide (2k):
v/v): H NMR (400 MHz, CDCl3):
δ
7.36ꢀ7.31 (m, 2H), 7.23ꢀ
= 7.2 Hz, 1H), 6.69
= 8.4, 4.0 Hz, 1H), 3.82 (s,
= 12.8, 4.0 Hz, 1H), 3.31 (dd, = 13.0, 8.4 Hz,
171.4, 140.0, 129.0, 1H); 13C NMR (100 MHz, CDCl3):
159.6, 147.9, 134.2,
128.7, 127.0, 74.4, 51.7, 28.8; IR (KBr) 3225, 1647, 1539, 129.5, 127.3, 118.4, 114.2, 113.7, 72.2, 55.5, 52.0; IR (Neat)
Colorless solid, mp = 103ꢀ104 C (lit.14 mp = 103ꢀ104 C); Rf 7.17 (m, 2H), 6.95ꢀ6.90 (m, 2H), 6.76 (t,
J
o
o
1
0.31; (hexanes : ethyl acetate, 70:30 v/v): H NMR (400 MHz, (dd,
J
= 8.6, 1.2 Hz, 2H), 4.89 (dd,
J
CDCl3):
δ
7.31ꢀ7.39 (m, 5H), 5.83 (bs, 1H), 4.89 (s, 1H), 1.32 3H), 3.40 (dd,
J
J
(s, 9H); 13C NMR (100 MHz, CDCl3):
δ
δ
6 | RSC Adv., 2014, 00, 1-8
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ARTICLE
DOI: 10.1039/C4RA13090A
3646, 1663, 1615, 1601, 1049 cm−1; HRMS (
calcd for C15H18NO2, 244.1338; found, 244.1330
m
/z
): [M+H]+ 1047 cm−1; HRMS (
m
/
z
): [M+H]+ calcd for C15H18NO,
228.1388; found, 228.1386.
1ꢀPhenylꢀ2ꢀ(oꢀtolylamino)ethanꢀ1ꢀol (3d):
1ꢀPhenylꢀ2ꢀ(piperidinꢀ1ꢀyl)ethanꢀ1ꢀol (3i):
Colourless oily liquid; Rf 0.35; (hexanes : ethyl acetate, 80:20 Colorless oily liqued; Rf 0.54; (hexanes : ethyl acetate, 80:20
1
1
v/v): H NMR (400 MHz, CDCl3):
7.31 (m, 1H), 7.17ꢀ7.12 (m, 1H), 7.10ꢀ7.06 (m, 1H), 6.74ꢀ6.68 (tt,
(m, 2H), 4.98 (dd, = 8.4, 4.0 Hz, 1H), 3.48 (dd, = 12.8, 4.0 (bs, 2H) 2.41 (dd,
= 13.0, 8.4 Hz, 1H), 2.15 (s, 3H); 13C NMR Hz, 3H), 1.61ꢀ1.48 (m, 4H), 1.40 (q,
145.9, 142.2, 130.4, 128.8, 128.2, 127.3, (100 MHz, CDCl3): 142.6, 128.4, 127.5, 126.0, 68.8, 67.1,
δ
7.76ꢀ7.38 (m, 4H), 7.36ꢀ v/v): H NMR (400 MHz, CDCl3):
δ
J
7.31ꢀ7.23 (m, 4H), 7.18
= 8.4, 2.8 Hz, 1H), 2.62
J = 10.0, 8.4
= 4.4 Hz, 2H); 13C NMR
J
= 5.6, 1.2 Hz, 1H), 4.65 (dd,
J
J
J
J
= 9.8, 2.8 Hz, 1H), 2.32 (dd,
Hz, 1H) 3.36 (dd,
J
(100 MHz, CDCl3):
δ
δ
126.0, 122.9, 117.8, 110.5, 72.6, 51.8, 17.6; IR (Neat) 3411, 54.6, 26.2, 24.4; IR (Neat) 3143, 1445, 1326, 1272, 1036 cm−1;
1602, 1511, 1453, 1051 cm−1; HRMS (
C15H18NO, 228.1388; found, 228.1397.
m
/z
): [M+H]+ calcd for HRMS (
m/z
): [M+H]+ calcd for C13H20NO, 206.1545; found,
206.1555.
2ꢀ((3ꢀMethoxyphenyl)amino)ꢀ1ꢀphenylethanꢀ1ꢀol (3e):
Methyl 2ꢀhydroxyꢀ2ꢀphenylacetate (18a):
Pale yellow oily liqued; Rf 0.36; (hexanes : ethyl acetate, 80:20 Colorless oily liquid; Rf 0.58; (hexanes : ethyl acetate, 70:30
1
v/v): 1H NMR (400 MHz, CDCl3):
δ
7.41ꢀ7.32 (m, 5H), 7.11 (t, v/v): H NMR (400 MHz, CDCl3):
= 8.0 Hz, 1H), 7.35ꢀ6.31 (m, 1H), 6.31ꢀ6.26 (m, 1H), 6.23 (t, 7.32 (m, 3H), 5.18 (s, 1H), 3.75 (s, 3H); 13C NMR (100 MHz,
= 2.0 Hz, 1H), 4.89 (dd, = 8.6, 4.0 Hz, 1H), 3.77 (s, 3H), CDCl3): 174.2, 138.4, 128.7, 128.6, 126.7, 73.0, 53.0; IR
= 13.2, 4.0 Hz, 1H), 3.27 (dd, ):
= 13.8, 8.4 Hz, 1H); (KBr) 3459, 1740, 1636, 1493, 1440, 1093 cm−1; HRMS (
13C NMR (100 MHz, CDCl3): 161.1, 149.5, 142.2, 130.2, [M+Na]+ calcd for C9H10O3Na1, 189.0528; found, 189.0524.
δ 7.44ꢀ7.40 (m, 2H), 7.39ꢀ
J
J
J
δ
3.39 (dd,
J
J
m/z
δ
128.8, 128.2, 126.0, 106.6, 103.4, 99.7, 72.7, 55.3, 51.9; IR
(Neat) 3465, 1613, 1456, 1411, 1049 cm−1; HRMS (
[M+H]+ calcd for C15H18NO2, 244.1338; found, 244.1328.
m
/
z
): 4ꢀ(1ꢀHydroxyethyl)benzonitrile (18b):
Colorless oily liquid; Rf 0.42; (hexanes : ethyl acetate, 70:30
1
v/v): H NMR (400 MHz, CDCl3): = 8.4, 1.6 Hz,
δ
7.61 (dt,
J
1ꢀPhenylꢀ2ꢀ((4ꢀ(CF3)phenyl)amino)ethanꢀ1ꢀol (3f):
2H), 7.47 (dd, = 8.4, 0.4 Hz, 2H), 4.94 (q, J = 6.4 Hz, 1H),
J
Pale yellow oily liqued; Rf 0.39; (hexanes : ethyl acetate, 80:20 1.48 (d,
J
= 6.4 Hz, 3H); 13C NMR (100 MHz, CDCl3):
δ
151.3,
7.44ꢀ7.33 (m, 7H), 6.67 132.4, 126.2, 119.0, 111.1, 69.7, 25.5; IR (Neat) 3417, 2229,
= 8.4, 4.0 Hz, 1H), 3.45 (dd,
1609, 1504, 1407, 1090 cm−1; HRMS ( ): [M+H]+ calcd for
= 13.2, 8.4 Hz, 1H); 13C NMR C9H10NO2, 148.0762; found, 148.0768.
1
v/v): H NMR (400 MHz, CDCl3):
δ
(d,
13.2, 4.0 Hz, 1H), 3.35 (dd,
(100 MHz, CDCl3):
126.8 (q,
3411, 1663, 1616, 1536, 1054 cm−1; HRMS (
calcd for C15H15F3NO, 282.1106; found, 282.1113.
J
= 8.4 Hz, 2H), 4.93 (dd,
J
J
=
m/z
J
δ
150.4, 141.8, 134.2, 128.9, 128.4, 127.8,
J
= 3.5 Hz, CF3), 126.0, 112.6, 72.7, 51.1; IR (Neat) 1ꢀ(3ꢀNitrophenyl)ethanꢀ1ꢀol (18c):
m
/
z
): [M+H]+ Colorless oily liquid; Rf 0.48; (hexanes : ethyl acetate, 70:30
1
v/v): H NMR (400 MHz, CDCl3):
δ
8.18 (t,
J = 2.0 Hz, 1H),
8.05 (ddd,
J
= 7.6 Hz, 1H), 7.66 (d,
J
= 7.6 Hz, 1H), 7.47 (d, J
2ꢀ((2ꢀChlorophenyl)amino)ꢀ1ꢀphenylethanꢀ1ꢀol (3g):
= 7.6 Hz, 1H) 4.97 (q,
J = 6.4 Hz, 1H), 2.78 (bs, 1H) , 1.48 (d,
Colorless oily liquid; Rf 0.38; (hexanes : ethyl acetate, 80:20 J = 6.4 Hz, 3H); 13C NMR (100 MHz, CDCl3):
δ 148.3, 148.0,
1
v/v): H NMR (400 MHz, CDCl3):
δ
J
7.45ꢀ7.38 (m, 4H), 7.34 131.7, 129.5, 122.3, 120.4, 69.3, 25.4; IR (KBr) 3371, 1530,
= 6.4, 1.2 Hz, 1H), 7.18ꢀ 1481, 1448, 1074 cm−1; HRMS ( ): [M+H]+ calcd for
= 6.4, 0.8 Hz, 1H), 6.70 (td, = 6.0, C8H10NO3, 168.0661; found, 168.0660.
= 6.8, 3.2 Hz, 1H), 3.48 (dd, = 10.4,
= 10.4, 6.8 Hz, 1H); 13C NMR (100 1ꢀ(4ꢀNitrophenyl)ethanꢀ1ꢀol (18d):
(tt,
J
= 5.6, 1.2 Hz, 1H), 7.28 (dd,
7.13 (m, 1H), 6.79 (dd,
1.2 Hz, 1H), 5.00 (dd,
3.2 Hz, 1H) 3.39 (dd,
m/z
J
J
J
J
J
MHz, CDCl3):
126.0, 120.3, 118.6, 112.4, 72.5, 51.9; IR (Neat) 3411, 1718, v/v): H NMR (400 MHz, CDCl3):
1663, 1593, 1062 cm−1; HRMS ( ): [M+H]+ calcd for 7.53 (d,
= 8.8 Hz, 2H), 5.01 (q,
1H), 1.51 (d,
= 6.8 Hz, 3H); 13C NMR (100 MHz, CDCl3):
153.2, 147.3, 126.2, 123.9, 69.6, 25.6; IR (KBr) 3387, 1602,
1518, 1451, 1086 cm−1; HRMS ( ): [M+H]+ calcd for
δ 143.4, 141.8, 129.5, 128.9, 128.3, 128.0, Colorless oily liqued; Rf 0.46; (hexanes : ethyl acetate, 70:30
1
δ
8.18 (d,
J = 8.8 Hz, 2H),
m
/
z
J
J = 6.8 Hz, 1H), 2.06 (bs,
C14H15ClNO, 248.0842; found, 248.0852.
J
δ
2ꢀ(Methyl(phenyl)amino)ꢀ1ꢀphenylethanol (3h):
m/z
Colorless oily liqued; Rf 0.62; (hexanes : ethyl acetate, 80:20 C8H10NO3, 168.0661; found, 168.0665.
1
v/v): H NMR (400 MHz, CDCl3):
7.19 (m, 3H), 6.81 (d, = 8.0 Hz, 2H), 6.74 (tt,
= 8.6, 4.4 Hz, 1H), 3.46 (dd,
= 14.8, 4.4 Hz, 1H), 2.88 (s, 3H); 13C NMR acetate, 80:20 v/v): H NMR (400 MHz, CDCl3):
150.0, 142.1, 129.4, 128.7, 127.9, 126.0, 7.6 Hz, 2H), 7.43ꢀ7.38 (m, 4H), 7.37ꢀ7.31 (m, 3H), 7.31ꢀ7.25
δ
7.39ꢀ7.30 (m, 4H), 7.29ꢀ
= 7.2, 0.8 Hz,
= 14.6, 8.8 Hz, Pale yellow solid; mp = 57ꢀ58 C, Rf 0.31; (hexanes : ethyl
J
J
(E)ꢀ1,3ꢀdiphenylpropꢀ2ꢀenꢀ1ꢀol (18e):
o
1H), 4.93 (dd,
1H), 3.38 (dd,
J
J
J
1
δ
7.47 (d,
J =
(100 MHz, CDCl3):
117.7, 113.4, 71.8, 62.1, 39.6; IR (Neat) 3404, 1453, 1374, (m, 1H), 6.72 (d,
1H), 5.41 (d,
δ
J
= 16.0 Hz, 2H), 6.42 (dd, J = 16.0, 6.4 Hz,
J
= 6.4 Hz, 1H), 2.24 (bs, 1H); 13C NMR (100
This journal is © The Royal Society of Chemistry 2012
RSC Adv., 2014, 00, 1-8 | 7

RSC Advances
Page 8 of 9
VJieowuArrtnicalelONnlainme e
ARTICLE
DOI: 10.1039/C4RA13090A
Chem. Soc., 2012, 134, 9727ꢀ9732. (f) Y. Li, L. Q. Lu, S. Das, S.
MHz, CDCl3):
δ 142.9, 136.7, 131.7, 130.7, 128.7, 128.6,
Pisiewicz, K. Junge and M. Beller, J. Am. Chem. Soc., 2012, 134
,
127.9, 127.2, 126.7, 126.5, 75.2; IR (KBr) 3406, 1645, 1604,
1492, 1445 cm−1; HRMS (m/z): [M+H]+ calcd for C15H15O,
211.1123; found, 211.1125.
18325ꢀ18329.
2
(a) Y. Nishibayashi, I. Takei, S. Uemura and M. Hidai,
Organometallics, 1998, 17, 3420ꢀ3422. (b) S. Enthaler, B. Eckhardt,
S. Inoue, E. Irran and M. Driess, Chem. Asian J., 2010,
(c) D. Addis, N. Shaikh, S. Zhou, S. Das, K. Junge and M. Beller,
Chem. Asian J., 2010, , 1687ꢀ1691. (d) F. F. Wu, J. N. Zhou, Q.
Fang, Y. H. Hu, S. Li, X. C. Zhang, A. S. C. Chan and J. Wu, Chem.
Asian J., 2012, , 2527ꢀ2530. (e) T. Inagaki, L. T. Phong, A. Furuta,
J. I. Ito and H. Nishiyama, Chem. Eur. J., 2010, 16, 3090ꢀ3096. (f) H.
Nishiyama and A. Furuta, Chem. Commun., 2007, 760ꢀ762. (g) S.
Sirol, J. Courmarcel, N. Mostefai and O. Riant, Org. Lett., 2001, 3,
4111ꢀ4113. (h) H. Mimoun, J. Y. de Laumer, L. Giannini, R.
Scopelliti and C. Floriani, J. Am. Chem. Soc., 1999, 121, 6158ꢀ6166.
(i) T. Inagaki, A. Ito, J. I. Ito and H. Nishiyama, Angew. Chem., Int.
Ed., 2010, 49, 9384ꢀ9387. (j) S. DiezꢀGonzalez and S. P. Nolan, Acc.
Chem. Res., 2008, 41, 349ꢀ358.
5, 2027ꢀ2035.
(
E
)ꢀ4ꢀphenylbutꢀ3ꢀenꢀ2ꢀol (18f):
5
Colorless oily liquid, Rf 0.28; (hexanes : ethyl acetate, 80:20
1
7
v/v): H NMR (400 MHz, CDCl3):
(td, = 6.8, 2.0 Hz, 2H), 7.19ꢀ7.14 (m, 1H), 6.49 (d,
Hz, 1H), 6.19 (dd, = 16.0, 6.4 Hz, 1H) 4.46ꢀ4.38 (m, 1H),
1.62 (bs, 1H), 1.30 (d,
= 6.4 Hz, 3H); 13C NMR (100 MHz,
CDCl3):
IR (Neat) 3354, 2973, 1646, 1494, 1450, 1062 cm−1; HRMS
(m/z): [M+H]+ calcd for C10H13O, 149.0966; found, 149.0967.
δ
7.33ꢀ7.29 (m, 2H), 7.24
J
J
= 16.0
J
J
δ
136.8, 133.7, 129.5, 128.7, 127.8, 126.6, 69.1, 23.5;
3
(a) S. Das, D. Addis, K. Junge and M. Beller, Chem. Eur. J., 2011,
17, 12186ꢀ12192. (b) S. Das, B. Join, K. Junge and M. Beller, Chem.
Commun., 2012, 48, 2683ꢀ2685. (c) Y. Sunada, H. Kawakami, T.
(
E)ꢀ3ꢀphenylꢀ1ꢀ(pꢀtolyl)propꢀ2ꢀenꢀ1ꢀol (18g):
Pale yellow oily liquid; Rf 0.34; (hexanes : ethyl acetate, 80:20
Imaoka, Y. Motoyama and H. Nagashima, Angew Chem Int Ed Engl
,
1
v/v): H NMR (400 MHz, CDCl3):
7.35 (t, = 8.0 Hz, 4H), 7.29 (d,
8.0 Hz, 2H), 6.72 (d, = 16.0 Hz, 1H), 6.42 (dd,
Hz, 1H), 5.39 (d, = 6.0 Hz, 1H), 2.40 (s, 3H), 2.22 (bs, 1H);
13C NMR (100 MHz, CDCl3):
140.0, 137.6, 136.7, 131.8,
δ
7.43 (d,
= 7.2 Hz, 1H), 7.23 (d,
= 16.0, 6.4
J = 7.2 Hz, 2H),
2009, 48, 9511ꢀ9514. (d) S. Das, D. Addis, S. Zhou, K. Junge and M.
Beller, J. Am. Chem. Soc., 2010, 132, 1770ꢀ1771. (e) C. Cheng and
M. Brookhart, J. Am. Chem. Soc., 2012, 134, 11304ꢀ11307. (f) A. C.
Fernandes and C. C. Romao, J. Mol. Catal. A: Chem., 2007, 272, 60ꢀ
63. (g) S. Das, B. Wendt, K. Moller, K. Junge and M. Beller, Angew
Chem Int Ed Engl, 2012, 51, 1662ꢀ1666. (h) R. Kuwano, M.
Takahashi and Y. Ito, Tetrahedron Lett., 1998, 39, 1017ꢀ1020. (i) R.
J
J
J =
J
J
J
δ
130.4. 129.4, 128.7, 127.8, 126.7, 126.5, 21.2; IR (Neat) 3453,
1605, 1505, 1452, 1039 cm−1; HRMS (m/z): [M+H]+ calcd for
C16H17O, 225.1279; found, 225.1280.
Kuwano, M. Takahashi and Y. Ito, Tetrahedron Lett., 1998, 39
,
1017ꢀ1020. (j) Y. Motoyama, K. Mitsui, T. Ishida and H. Nagashima,
J. Am. Chem. Soc., 2005, 127, 13150ꢀ13151. (k) M. Igarashi and T.
Fuchikami, Tetrahedron Lett., 2001, 42, 1945ꢀ1947. (l) S. Hanada, E.
Tsutsumi, Y. Motoyama and H. Nagashima, J. Am. Chem. Soc., 2009,
131, 15032ꢀ15040. (3m) A. M. Smith and R. Whyman, Chem. Rev.
2014, 114, 5477ꢀ5510.
(
E)ꢀ1ꢀ(naphthalenꢀ1ꢀyl)ꢀ3ꢀphenylpropꢀ2ꢀenꢀ1ꢀol (18h):
Yellow oily liquid; Rf 0.31; (hexanes : ethyl acetate, 80:20
1
v/v): H NMR (400 MHz, CDCl3):
(dd, = 6.8, 2.8 Hz, 1H), 7.61 (d,
δ
8.04ꢀ8.00 (m, 1H), 7.68
4
5
(a) S. Chakraborty, J. A. Krause and H. Guan, Organometallics
2009, 28, 582ꢀ586. (b) B. H. Lipshutz, A. Lower and K. Noson, Org.
Lett., 2002, , 4045ꢀ4048. (c) K. Riener, M. P. Hoegerl, P. Gigler and
F. E. Kuehn, ACS Catal., 2012, , 613ꢀ621.
(a) R. Roesler, B. J. N. Har and W. E. Piers, Organometallics, 2002,
21, 4300ꢀ4302. (b) D. J. Parks and W. E. Piers, J. Am. Chem. Soc.
,
J
J = 7.2 Hz, 1H), 7.33ꢀ7.25
4
(m, 3H), 7.19ꢀ7.15 (m, 2H), 7.12ꢀ7.06 (m, 2H), 7.05ꢀ7.01 (m,
1H) 6.57 (d, = 16.0, 1H), 6.37 (dd, = 16.0, 6.0 Hz, 1H), 5.88
(d,
= 5.6 Hz, 1H), 2.10 (s, 1H); 13C NMR (100 MHz, CDCl3):
138.4, 136.7, 134.1, 131.2, 131.1, 130.8, 129.0, 128.7, 127.9,
2
J
J
J
,
δ
1996, 118, 9440ꢀ9441. (c) N. Asao, T. Ohishi, K. Sato and Y.
Yamamoto, J. Am. Chem. Soc., 2001, 123, 6931ꢀ6932. (d) J. M.
Blackwell, D. J. Morrison and W. E. Piers, Tetrahedron, 2002, 58
8247ꢀ8254. (e) N. Asao, T. Ohishi, K. Sato and Y. Yamamoto,
Tetrahedron, 2002, 58, 8195ꢀ8203. (f) M. Fujita, S. Fukuzumi and J.
Otera, J. Mol. Catal., 1993, 85, 143ꢀ148. (g) Y. Izumi and M. Onaka,
J. Mol. Catal., 1992, 74, 35ꢀ42.
(a) M. Onaka, K. Higuchi, H. Nanami and Y. Izumi, Bull. Chem. Soc.
Jpn., 1993, 66, 2638ꢀ2645. (b) M. Hojo, C. Murakami, A. Fujii and
A. Hosomi, Tetrahedron Lett., 1999, 40, 911ꢀ914. (c) F. Le Bideau,
126.7, 126.3, 125.8, 125.6, 124.1, 123.9, 72.2; IR (Neat) 3595,
2252, 1643, 1600, 1501, 1454 cm−1; HRMS (m/z): [M+H]+
calcd for C19H17O, 261.1279; found, 261.1281.
,
Acknowledgements
6
We thank DST (project No: SB/S1/OCꢀ72/2013) and DST nano
mission (SR/NM/NSꢀ1034/2012(G)) for financial support.
NCM thanks CSIR, New Delhi for senior research fellowship.
T. Coradin, D. Gourier, J. Henique and E. Samuel, Tetrahedron Lett.
,
2000, 41, 5215ꢀ5218. (d) M. Hojo, A. Fujii, C. Murakami, H. Aihara
and A. Hosomi, Tetrahedron Lett., 1995, 36, 571ꢀ574. (e) D. Addis,
S. Zhou, S. Das, K. Junge, H. Kosslick, J. Harloff, H. Lund, A.
Notes and references
aDepartment of Chemistry, Indian Institute of Technology Madras,
Chennai, 600 036, India. E-mail: gsekar@iitm.ac.in; Fax: +91 44 2257
4202; Tel: +91 44 2257 4229.
Schulz and M. Beller, Chem. Asian J., 2010, 5, 2341ꢀ2345. (f) M.
Zhao, W. Xie and C. Cui, Chem. Eur. J., 2014, 20, 9259ꢀ9262.
(a) D. Yang and D. D. Tanner, J. Org. Chem., 1986, 51, 2267ꢀ2270.
(b) M. Fujita and T. Hiyama, J. Org. Chem., 1988, 53, 5405ꢀ5415. (c)
Y. Kawanami, H. Yuasa, F. Toriyama, S.ꢀi. Yoshida and T. Baba,
7
†Electronic Supplementary Information (ESI) available: [details of any
supplementary information available should be included here]. See
DOI: 10.1039/b000000x/
Catal. Commun., 2003, 4, 455ꢀ459. (d) Y. Kobayashi, E. Takahisa,
M. Nakano and K. Watantani, Tetrahedron, 1997, 53, 1627ꢀ1634. (e)
C. Bornschein, S. Werkmeister, K. Junge and M. Beller, New J.
Chem., 2013, 37, 2061ꢀ2065.
1
(a) M. Szostak, M. Spain and D. J. Procter, Chem. Soc. Rev., 2013,
42, 9155ꢀ9183. (b) R. A. Shenvi, D. P. O'Malley and P. S. Baran,
Acc. Chem. Res., 2009, 42, 530ꢀ541. (c) K. Junge, B. Wendt, N.
Shaikh and M. Beller, Chem. Commun. 2010, 46, 1769ꢀ1771. (d) R.
8
9
K. Revunova and G. I. Nikonov, Chem. Eur. J., 2014, 20, 839ꢀ845.
J. A. FernandezꢀSalas, S. Manzini and S. P. Nolan, Chem. Commun.
2013, 49, 9758ꢀ9760.
,
10 S. Das, D. Addis, L. R. Knoepke, U. Bentrup, K. Junge, A. Brueckner
J. Rahaim, Jr. and R. E. Maleczka, Jr., Org. Lett., 2005,
5090. (e) Y. Li, S. Das, S. Zhou, K. Junge and M. Beller, J. Am.
7, 5087ꢀ
and M. Beller, Angew. Chem., Int. Ed., 2011, 50, 9180ꢀ9184.
8 | RSC Adv., 2014, 00, 1-8
This journal is © The Royal Society of Chemistry 2012

Page 9 of 9
Journal Name
RSC Advances
View Article Online
ARTICLE
DOI: 10.1039/C4RA13090A
11 Y. Li, J. A. Molina de La Torre, K. Grabow, U. Bentrup, K. Junge, S.
Zhou, A. Brueckner and M. Beller, Angew. Chem., Int. Ed., 2013, 52
,
11577ꢀ11580.
12 G. Barbe and A. B. Charette, J. Am. Chem. Soc., 2008, 130, 18ꢀ19.
13 (a) W. Xie, M. Zhao and C. Cui, Organometallics, 2013, 32, 7440ꢀ
7444. (b) E. Blondiaux and T. Cantat, Chem. Commun. 2014, 50
,
9349ꢀ9352. (c) R. C. Chadwick, V. Kardelis, P. Lim and A. Adronov,
J. Org. Chem., 2014, 79, 7728ꢀ7733.
14 N. C. Mamillapalli, G. Sekar, Chem. Commun., 2014, 50, 7881ꢀ
7884.
15 V. Rajesh kumar, C. S. and G. Sekar, Org. Biomol. Chem., 2014,
DOI: 10.1039/C4OB01564A.
16 (a) S. L. Shapiro, I. M. Rose and L. Freedman, J. Am. Chem. Soc.
,
1959, 81, 6322ꢀ6329. (b) S. L. Shapiro, I. M. Rose and L. Freedman,
J. Am. Chem. Soc., 1959, 81, 3083ꢀ3088.
17 (a) J. E. Clifton, I. Collins, P. Hallett, D. Hartley, L. H. C. Lunts and
P. D. Wicks, J. Med. Chem., 1982, 25, 670ꢀ679. (b) D. T. Collin, D.
Hartley, D. Jack, L. H. C. Lunts, J. C. Press, A. C. Ritchie and P.
Toon, J. Med. Chem., 1970, 13, 674ꢀ680. (c) F. B. Ablondi, J. J.
Hagen and R. E. Clarke, Proc. Soc. Exptl. Biol. Med., 1957, 95, 195ꢀ
200. (d) P. Das and B. J. K. De, Tetrahedron, 2013, 69, 7646ꢀ7652.
18 H. Mayr, N. Basso and G. Hagen, J. Am. Chem. Soc., 1992, 114
,
3060ꢀ3066.
19 Sensitive functional groups like nitrile, ester, nitro, phenyl benzamide
and methyl benzamide gave several inseparable products in the
complete reduction condition.
20 (a) R. R. Holmes, Chem. Rev., 1996, 96, 927ꢀ950. (b) C. Chuit, R. J.
P. Corriu, C. Reye and J. C. Young, Chem. Rev., 1993, 93, 1371ꢀ
1448.
21 K. Matsumoto, S. Hashimoto and S. Otani, Angew. Chem., 1986, 98
,
569ꢀ570.
This journal is © The Royal Society of Chemistry 2012
RSC Adv., 2014, 00, 1-8 | 9