Stille couplings in water at room temperature

Article abstract of DOI:10.1039/c2gc36042j

A nonionic amphiphile, TPGS-750-M, enables efficient Stille couplings between a wide range of substrates to be conducted in water as the only medium, in most cases at room temperature.

Full text of DOI:10.1039/c2gc36042j

Cutting-edge research for a greener sustainable future
www.rsc.org/greenchem
Volume 15 | Number 1 | January 2013 | Pages 1–268
ISSN 1463-9262
PAPER
Bruce H. Lipshutz et al.
Stille couplings in water at room temperature
1463-9262(2013)15:1;1-Q

Green Chemistry
View Article Online
View Journal | View Issue
PAPER
Stille couplings in water at room temperature†
Guo-ping Lu,a,b Chun Caib and Bruce H. Lipshutz*a
Cite this: Green Chem., 2013, 15, 105
Received 6th July 2012,
Accepted 14th September 2012
A nonionic amphiphile, TPGS-750-M, enables efficient Stille couplings between a wide range of sub-
strates to be conducted in water as the only medium, in most cases at room temperature.
DOI: 10.1039/c2gc36042j
www.rsc.org/greenchem
for conducting Stille couplings in an aqueous solution con-
taining TPGS-750-M, in most cases at room temperature.
Introduction
In a recent review on Nobel Prize-winning Suzuki, Heck, and
Negishi couplings by Colacot, Snieckus and co-workers,1 data
was presented indicative of the number of papers and patents
associated with each of the commonly used cross-coupling
reactions from the last decade. While Suzuki, Heck, and Sono-
gashira reactions ranked among the top three, fourth was
Stille couplings with ca. 2000 citations. Thus, Pd-catalyzed
Stille couplings of various organo- and pseudo-halides with
organostannanes represent one of the most powerful tools for
the formation of carbon–carbon bonds.2 Their popularity is
usually attributed to the stability and functional group toler-
ance of stannanes, as well as their chemoselectivity and broad
scope in terms of reaction partners.3 Traditionally, Stille coup-
lings are carried out in organic solvents (e.g., THF, DMF,
NMP), and oftentimes at temperatures above ambient.4
Although many attempts have been made to perform these
reactions under thermally mild conditions,5 use of (potentially
toxic) organic solvents is always the norm, which by definition
fails to meet the 12 Principles of Green Chemistry.6
Ideally, Stille couplings would be carried out at room temp-
erature, in water as the only medium. Several nanometal cata-
lysts have been designed to enable Stille couplings to be run
under such conditions.7 However, opportunities for variation
in substrate type are limited. More commonly, high tempera-
tures are required in the presence of various Pd catalysts.8
Recently, we have reported that TPGS-750-M (polyethanol-
α-tocopherylsuccinate; shown below) is an excellent commer-
cially available “designer” surfactant that self-assembles in
water to form nanomicelles within which several cross-coup-
lings efficiently take place.9 Herein, we describe a new protocol
Results and discussion
Scattered literature reports have mentioned that Pd(P(t-Bu)3)2
is an unusually reactive catalyst for Stille couplings of aryl bro-
mides and chlorides.4a,5c,10 Thus, three aryl bromides were
initially coupled with vinyl- or 2-furyltributyltin using Pd(P(t-
Bu)3)2 (2 mol%). Using 2 wt.% aqueous TPGS-750-M at room
temperature (0.25 M), excellent yields of products 1–3 were
obtained in two to four hours (Scheme 1).
Based on these initial results, both 3-chlorotoluene and
2-furyltributyltin were selected to investigate potential coup-
lings between aryl chlorides, and to further optimize reaction
conditions to be applied to couplings involving more challen-
ging organotin partners (Table 1). Initially, several commonly
used catalysts and additives were screened (entries 1–14). The
combination of Pd(P(t-Bu)3)2 and DABCO4c,11 emerged as the
best choice. Remarkably, the limited conversion initially
observed could be increased dramatically by adding one equiv-
alent of NaCl (entries 15, 16), but not NaF (entry 17),
aDepartment of Chemistry & Biochemistry, University of California, Santa Barbara,
California 93106, USA. E-mail: lipshutz@chem.ucsb.edu
bChemical Engineering College, Nanjing University of Science & Technology, Nanjing,
Jiangsu 210094, P. R. China
†Electronic supplementary information (ESI) available: More experimental
details and characterization data of all products. See DOI: 10.1039/c2gc36042j
Scheme 1 Stille couplings with aryl bromides in water at room temperature.
Green Chem., 2013, 15, 105–109 | 105
This journal is © The Royal Society of Chemistry 2013

View Article Online
Paper
Green Chemistry
Table 1 Optimization of reaction conditionsa
reaction was conducted “on water” (entry 28), indicative of the
vagaries associated with this type of approach to cross-coup-
lings, as observed previously on many occasions.13
With optimized conditions in hand, several combinations
of aryl halides and organotin reagents were investigated to
ascertain the scope of the protocol (Table 2). In general, aryl
bromides coupled smoothly at room temperature. Tributylphe-
nyltin appeared to be a less active coupling partner than other
organotin reagents. Although in the case of p-bromoanisole
(entry 5), P(P(t-Bu)3)2 led to full conversion at 50 °C, a poor
yield of desired product was obtained due to homocoupling of
the bromide. Switching to Pd2(dba)3/P(o-Tol)3 with increased
catalyst loading (4 mol%) was found to enhance the yield at
the expense of homocoupling.
The analogous reactions of aryl chlorides, not surprisingly,
were more sluggish. However, in some cases, e.g., 2-furyltri-
butyltin and p-chlorobenzonitrile, the coupling was successful
even at room temperature (entry 4). Generally, the couplings
took place under the influence of mild heat, along with an
increase in catalyst loading to 4 mol% (entries 9, 13–16). No
product was formed, however, in the reaction of an electron-rich
aryl chloride (e.g., o-chloroanisole) with tributyl(phenylethynyl)-
stannane (entry 11). It should be noted that the byproduct
4-butyl-2-nitrotoluene was formed when 4-chloro-2-nitrotoluene
was coupled with either of two tributylstannanes (entries 13,
15). The by-product in the case of Bu3SnPh could be avoided by
switching to the trimethylstannyl analog (entry 14).
Entry
Surfactant
Additive
Conversionb (%)
1c
2d
3e
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
TPGS-750-M
TPGS-750-M
TPGS-750-M
TPGS-750-M
TPGS-750-M
TPGS-750-M
TPGS-750-M
TPGS-750-M
TPGS-750-M
TPGS-750-M
TPGS-750-M
TPGS-750-M
TPGS-750-M
TPGS-750-M
TPGS-750-M
TPGS-750-M
TPGS-750-M
None
/
/
/
NR
20
NR
27
NR
14
4
17
30
7
34
/
CuIf
LiCl
CsF
Bu4NF
Net3
NaOH
K2CO3
K2CO3 + CuClf
K2CO3 + ZnBr2
DABCO
NaClg
17
12
37
f
32
DABCO + NaClg
DABCO + NaFg
DABCO + NaClg
DABCO + NaClg
DABCO + NaClg
DABCO + NaClg
DABCO + NaClg
50, 85h,i
35
39
50
40
39
SDS
Trition X-100
Brij 30
CTAB
55
To compare and contrast these couplings, guided by the
principles of green chemistry,5 with traditional Stille coupling
conditions, a direct comparison was performed between 3-
bromobenzothiophene and 2-furyltributyltin (Scheme 2).
Rather than an organic solvent (dioxane), additives (excess
cesium fluoride), and heat (80 °C),14 the “green” protocol
afforded a considerably higher yield, done in water at room
temperature, and in a shorter time frame.
Likewise, Stille couplings with alkenyl halides could also be
effected under otherwise identical conditions (Table 3). Both
alkenyl iodides and bromides readily participate at room temp-
erature to afford products 18–21 (entries 1–4). In the case of
(Z)-β-bromostyrene, significant undesired Z-to-E isomeriza-
tion,15 as well as homocoupling, took place (entry 5). However,
switching catalysts from Pd(P(t-Bu)3)2 to Pd2(dba)3/P(o-Tol)3
led to retention of stereochemistry giving Z-22 in high yield,
while avoiding homocoupling (entry 6).
Interestingly, while the literature illustrates a traditional
coupling between Z-alkenyl triflate 23 and tributyl-4-methoxy-
phenylstannane in NMP leading to isomerized E-product 24,16
the desired Z-24 is formed under micellar conditions
(Scheme 3). To further demonstrate the potential of this meth-
odology, dienoate 25, a crucial intermediate en route to mam-
malian V-ATPase inhibitor 26,17 was smoothly generated by
reaction between (E)-ethyl 3-iodoacrylate and (E)-3-(tributyl-
stannyl)-prop-2-en-1-ol, yielding the unprotected alcohol 25 in
water at room temperature (Scheme 4).
23
24
25
26
27
28
TPGS-750-M
TPGS-750-M
TPGS-750-M
TPGS-750-M
CTAB
/
12
14
K2CO3
DABCO
44
DABCO + NaClg
DABCO + NaClg
DABCO + NaClg
76i, 85i,j
68i
None
12
a Conditions: aryl halide (0.250 mmol), organotin reagent
(0.275 mmol), Pd(P(t-Bu)3)2 (0.005 mmol for entries 1–22, 0.010 mmol
for entries 23–28), solution of aqueous surfactant (2 wt.%, 1 mL),
additive (0.750 mmol) rt, 24 h. b Conversion determined by GC. c The
catalyst is Pd(P(t-Bu)2OH)2Cl2 (2 mol%). d The catalyst is Pd(OAc)2/
2Xphos (2 mol%). e The catalyst isPd2(dba)3/4P(o-Tol)3 (1 mol%).
f 20 mol%. g 1.0 equiv. h At 50 °C. i Isolated yield. j At 40 °C.
presumably due to the enlarged, reorganized micelles which
offer increased surface area and thus, increased binding con-
stants for substrates and catalysts.9 Alternatively, the positive
effects of chloride on the palladium center may be operative.12
A good yield of product 4 (85%) could be achieved by slight
heating to 50 °C. The corresponding coupling run “on water”
(i.e., in the absence of TPGS-750-M), led to lower conversion
(entry 16 vs. entry 18).13 Screening various surfactants indi-
cated that both CTAB, an ionic surfactant (entry 22), and the
neutral amphiphile TPGS-750-M were equally effective in this
model reaction.
On the other hand, in the reaction between 2-bromo-1,3-
dimethylbenzene and (E)-3-(tributylstannyl)allyl acetate,
TPGS-750-M proved to be more effective than CTAB, run under
otherwise identical conditions (entry 26 vs. 27). Very low con-
version to the desired product 5 was observed when the
Finally, the prospects for recycling aqueous solutions of
TPGS-750-M used in Stille couplings were studied (Table 4).
106 | Green Chem., 2013, 15, 105–109
This journal is © The Royal Society of Chemistry 2013

View Article Online
Green Chemistry
Paper
Table 2 Stille couplings with aryl halides in aqueous TPGS-750-Ma
Entry
1
X
Time (h)
24
T (°C)
Product
Yieldb (%)
93
Br
rt
Scheme 2 The reaction of 3-bromobenzothiophene with 2-furyltributyltin.
Table 3 Stille couplings of alkenyl halides under aqueous micellar conditionsa
2
3
Br
Br
4
4
rt
rt
88
94
Entry
1
X
I
Time (h) Product
6
Yieldb (%)
18 88
4
Cl
24
rt
94
5
6
Br
Br
24
4
50
rt
39, 80c
91
2
I
4
19 91
3
4
Br 24
20 89
I
2
21 94 (Z/E = 99/1)
7
Br
5
rt
92
5c
6c
Br 24
Br 24
22 50 (Z/E = 90/10)d
90 (Z/E = 96/4)d,e
a Conditions: alkenyl halide (0.250 mmol), organotin reagent
(0.275 mmol), Pd(P(t-Bu)3)2 (0.005 mmol), aqueous TPGS-750-M
solution (2 wt.%, 1.0 mL), DABCO (0.750 mmol), NaCl (0.250 mmol),
rt. b Isolated yield. c The Z/E ratio of β-bromostyrene is 96/4. d Z/E ratio
of product is determined by GC on the crude products. e 1 mol%
Pd2(dba)3 and 4 mol% P(o-Tol)3 are used as catalyst.
8
9
Br
Cl
1
24
rt
50
95
75d
10
11
Br
Cl
4
24
rt
50
97
NRd
12
Br
5
rt
97
13
14
Cl
Cl
24
24
60
60
78d,e
92d,f
15
16
Cl
Cl
24
24
50
60
45d
73d
Scheme 3 Stille couplings with a Z-alkenyl triflate.
After the successful coupling of 2-bromo-1,3-dimethylbenzene
and tributyl(phenylethynyl)stannane under optimized con-
ditions (entry 1), in-flask extractions with minimal amounts of
hexane led to facile product isolation. The extraction also
removed much of the Pd catalyst, accounting for the reduced
a Conditions: aryl halide (0.250 mmol), organotin reagent (0.275 mmol), Pd(P(t-
Bu)3)2 (0.005 mmol), aqueous TPGS-750-M solution (2 wt.%, 1 mL), DABCO
(0.750 mmol), NaCl (0.250 mmol). b Isolated yield. c 2 mol% Pd2(dba)3 and 8 mol
% P(o-Tol)3 are used as catalyst. d 4 mol% Pd(P(t-Bu)3)2 is used. e A mixture of 15
and 4-butyl-2-nitrotoluene (3 : 1) determined by 1H NMR. f Trimethylphenyltin
(1.1 equiv) used.
This journal is © The Royal Society of Chemistry 2013
Green Chem., 2013, 15, 105–109 | 107

View Article Online
Paper
Green Chemistry
Experimental
General procedure for Stille couplings in water
The palladium catalyst (0.005 mmol), organohalides
(0.250 mmol), DABCO (0.750 mmol) and NaCl (0.250 mmol)
were weighed into a microwave vial at room temperature, and
the organotin reagent (0.275 mmol) and 2 wt.% aqueous
TPGS-750-M solution (1.0 mL) were then added by syringe.
(The liquid organohaildes were also added by syringe.) The
resulting solution was allowed to stir at room temperature
(slight heating was required in some cases) and monitored by
GC or TLC. Upon completion, the reaction mixture was then
diluted with NEt3 (0.3 mL) and EtOAc (4.0 mL), filtered
through a bed of silica gel layered over Celite. The volatiles
were removed in vacuo to afford the crude product. The extent
of conversion and Z/E ratios were determined by GC. Further
column chromatography on silica gel afforded the pure
desired product.
Scheme 4 A potential application of Stille couplings to total synthesis.
Table 4 The recycling of the aqueous solution of TPGS-750-Ma
Procedure for recycling aqueous solutions of TPGS-750-M
After completion of the reaction, the mixture was extracted by
hexane (4 × 1 mL). The organic layer was separated from the
aqueous layer by syringe. The remaining hexane in the micel-
lar solution was removed in vacuo. For the second run, fresh
starting materials and Pd(P(t-Bu)3)2 (2 mol%) were added to
the aqueous solution, and the reaction was conducted as
described for the initial run.
Entry
Run
Time (h)
Yieldb (%)
1
1
2
3
4
5
4
4
6
6
6
91
2c
3c
4c
5c
80d (22)e
92
89
88
a Conditions: 2,6-dimethylbromobenzene (0.250 mmol), tributyl
phenylethynyltin (0.275 mmol), Pd(P(t-Bu)3)2 (0.005 mmol), aqueous
TPGS-750-M solution (2 wt.%, 1.0 mL), DABCO (0.750 mmol), NaCl
(0.250 mmol), rt. b Isolated yield. c Additional 2 mol% Pd(P(t-Bu)3)2 is
used. d Yield after 4 h with additional 2 mol% Pd(P(t-Bu)3)2. e No
additional Pd(P(t-Bu)3)2 added; conversion determined by GC.
Characterization data of new compounds
(E)-3-(2,6-Dimethylphenyl)allyl
acetate
(5). 1H
NMR
(500 MHz, CDCl3) δ 2.11 (s, 3H), 2.29 (s, 6H), 4.75–4.76 (dd, J =
6.5, 1.5 Hz, 2H), 5.77–5.87 (dt, J = 16.0, 6.3 Hz, 1H), 6.63–6.66
(d, J = 16.5 Hz, 1H), 7.02–7.08 (m, 3H). 13C NMR (125 MHz,
CDCl3) δ 20.8, 21.0, 65.2, 126.9, 127.7, 128.6, 131.9, 135.9,
170.8. HRMS(EI) Calcd for C13H16O2 204.1150, found
204.1142.
yield (22%; entry 2). The addition of fresh catalyst to each
recycle increased the level of conversion and the resulting
yields returned to that seen in the initial experiment (entries
3–5).
2-(2-Methoxynaphthalen-1-yl)furan (7). 1H NMR (500 MHz,
CDCl3) δ 3.93 (s, 3H), 6.30 (d, J = 1.5 Hz, 2H), 7.34–7.46 (m,
3H), 7.66–7.67 (t, J = 1.5 Hz, 1H), 7.81–7.91 (m, 3H). 13C NMR
(125 MHz, CDCl3) δ 56.8, 110.8, 111.3, 113.5, 114.5, 123.8,
125.1, 126.9, 128.0, 129.0, 130.7, 133.7, 142.2, 148.8, 155.6.
HRMS(EI) Calcd for C15H12O2 224.0837, found 224.0839.
Conclusions
In summary, Stille couplings can be performed in water typi-
3,4,5-Trimethoxy-2-(phenylethynyl)benzaldehyde
(11). 1H
cally at room temperature by employing nanoreactors formed NMR (500 MHz, CDCl3) δ 3.94 (s, 3H), 3.99 (s, 3H), 4.04 (s,
from the nonionic designer surfactant TPGS-750-M. The cata- 3H), 7.28 (s, 1H), 7.37–7.38 (m, 3H), 7.55–7.57 (m, 2H), 10.53
lyst system Pd(P(t-Bu)3)2/DABCO leads, in many cases, to a (s, 1H). 13C NMR (125 MHz, CDCl3) δ 56.2, 61.2, 61.5, 80.6,
wide range of couplings between various organostannanes and 99.2, 105.3, 115.9, 122.7, 128.5, 128.8, 131.5, 131.8, 147.6,
both aryl and alkenyl halides. The newly developed procedures 154.0, 154.6, 190.6. HRMS(ESI) Calcd for C18H16O4 296.1049,
are environmentally friendly in that no organic solvent is found (M + Na)+ 319.0933.
required in these couplings, limited amounts of water are
4-(4-Methyl-3-nitrophenyl)-3,6-dihydro-2H-pyran
(16). 1H
invested, and workup entails only an in-flask extraction with a NMR (500 MHz, CDCl3) δ 2.50–2.53 (m, 2H), 2.59 (s, 3H),
minimal amount of a single, recoverable organic solvent. 3.94–3.96 (t, J = 5.5 Hz, 2H), 4.33–4.35 (q, J = 3.0 Hz, 2H),
These reactions take place in high yields and stereoselectivity, 6.22–6.24 (m, 1H), 7.30 (d, J = 8.0 Hz, 1H), 7.51–7.53 (dd, J =
thereby offering considerable potential for applications to 8.0, 2.0 Hz, 1H), 7.98 (d, J = 1.5 Hz, 1H). 13C NMR (125 MHz,
complex targets in organic synthesis.
CDCl3) δ 20.1, 26.9, 64.2, 65.7, 120.7, 124.3, 128.9, 132.1, 132.2,
108 | Green Chem., 2013, 15, 105–109
This journal is © The Royal Society of Chemistry 2013

View Article Online
Green Chemistry
Paper
132.8, 139.3, 149.3 HRMS(ESI) Calcd for C12H13NO3 219.0895,
found (M + Na)+ 242.0781.
Chem.–Eur. J., 2005, 11, 3294; (c) J.-H. Li, Y. Liang,
D.-P. Wang, W.-J. Liu, Y.-X. Xie and D.-L. Yin, J. Org. Chem.,
2005, 70, 2832.
(2E,4E)-Undeca-2,4-dien-1-ol (18). 1H NMR (500 MHz,
CDCl3) δ 0.87–0.90 (t, J = 7.0 Hz, 3H), 1.26–1.39 (m, 8H),
2.06–2.10 (q, J = 7.0 Hz, 2H), 4.15–4.17 (t, J = 5.8 Hz, 2H),
5.68–5.75 (m, 2H), 6.02–6.07 (dd, J = 15.0, 10.0 Hz, 1H),
6.19–6.24 (dd, J = 15.5, 10.5 Hz, 1H). 13C NMR (125 MHz,
CDCl3) δ 14.1, 22.6, 28.9, 29.2, 31.7, 32.6, 63.6, 129.3, 132.2,
135.9. HRMS(EI) Calcd for C11H20O 168.1514, found 168.1513.
5 (a) J. K. Stille and B. L. Groh, J. Am. Chem. Soc., 1987, 109,
813; (b) J. K. Stille and J. H. Simpson, J. Am. Chem. Soc.,
1987, 109, 2138; (c) A. F. Littke, L. Schwarz and G. C. Fu,
J. Am. Chem. Soc., 2002, 124, 6343; (d) D.-H. Lee, A. Taher,
W.-S. Ahn and M.-J. Jin, Chem. Commun., 2010, 46, 478;
(e) W. Su, S. Urgaonkar, P. A. McLaughlin and
J. G. Verkade, J. Am. Chem. Soc., 2004, 126, 16433.
6 (a) P. T. Anastas and J. C. Warner, Green Chemistry: Theory
and Practice, Oxford University Press, Oxford, UK, 1998;
(b) P. T. Anastas and T. Williamson, Green Chemistry, Fron-
tiers in Benign Chemical Synthesis and Process, Oxford Uni-
versity of Press, Oxford, UK, 1998; (c) C. Capello, U. Fischer
and K. Hungerbuhler, Green Chem., 2007, 9, 927.
7 (a) J. C. Garcia-Martinez, R. Lezutekong and R. M. Crooks,
J. Am. Chem. Soc., 2005, 127, 5097; (b) M. A. Bernechea,
M. E. de Jesús, C. López-Mardomingo and P. Terreros,
Inorg. Chem., 2009, 48, 4491; (c) L. Wu, X. Zhang and
Z. Tao, Catal. Sci. Technol., 2012, 2, 707.
8 C. Wolf and R. Lerebours, J. Org. Chem., 2003, 68, 7551.
9 (a) B. H. Lipshutz, S. Ghorai, A. R. Abela, R. Moser,
T. Nishikata, C. Duplais, A. Krasovskiy, R. D. Gaston and
R. C. Gadwood, J. Org. Chem., 2011, 76, 4379;
(b) B. H. Lipshutz, B. R. Taft and A. R. Abela, Platin. Met.
Rev., 2012, 56, 62; (c) B. H. Lipshutz and S. Ghorai, Aldrichi-
mica Acta, 2008, 41, 59; (d) B. H. Lipshutz and S. Ghorai,
Aldrichimica Acta, 2012, 45, 3.
(E)-(4-Methyldec-3-en-1-ynyl)benzene
(19). 1H
NMR
(500 MHz, CDCl3) δ 0.88–0.91 (t, J = 7.0 Hz, 3H) 1.26–1.33 (m,
6H), 1.43–1.54 (m, 2H), 1.97 (s, 3H), 2.21–2.15 (t, J = 7.5 Hz,
2H), 5.49 (s, 1H), 7.26–7.32 (m, 3H), 7.42–7.44 (dd, J = 7.5,
1.5 Hz, 2H). 13C NMR (125 MHz, CDCl3) δ 14.1, 19.4, 22.6,
27.6, 28.9, 31.7, 38.8, 87.8, 91.7, 104.6, 124.1, 127.6, 128.2,
131.2, 153.0. HRMS(EI) Calcd for C17H22 226.1722, found
226.1728.
(E)-(4-(Furan-2-yl)but-3-enyloxy)triisopropylsilane
(20). 1H
NMR (500 MHz, CDCl3) δ 1.07 (s, 18H), 2.41–2.45 (m, 3H),
3.69–3.83 (m, 4H), 6.14–6.39 (m, 5H), 7.03 (d, J = 2.0 Hz, 1H).
13C NMR (125 MHz, CDCl3) δ 12.0, 18.0, 36.6, 63.1, 106.2,
111.0, 120.2, 126.2, 141.3, 153.2. HRMS(EI) Calcd for
C17H30O2Si 294.2015, found 294.1991.
(2Z,4E)-Ethyl 6-hydroxy-3-methylhexa-2,4-dienoate (21). 1H
NMR (500 MHz, CDCl3) δ 1.26–1.29 (t, J = 7.3 Hz, 3H), 2.01 (d,
J = 1.0 Hz, 3H), 4.14–4.18 (q, J = 7.0 Hz, 2H), 4.32 (br, 2H), 5.70
(s, 1H), 6.20–6.25 (dt, J = 16.0, 5.5 Hz, 1H), 7.72–7.76 (dd, J =
16.0, 1.0 Hz, 1H). 13C NMR (125 MHz, CDCl3) δ 14.3, 21.0,
59.8, 63.6, 117.9, 127.8, 135.9, 150.0, 166.2. HRMS(EI) Calcd
for C9H14O3 170.0943, found 170.0950.
10 C. G. Fu, Acc. Chem. Res., 2008, 41, 1555.
11 J.-H. Li, X.-C. Hu, Y. Liang and Y.-X. Xie, Tetrahedron, 2006,
62, 31.
12 (a) B. H. Lipshutz, S. Ghorai, W. W. Y. Leong, B. R. Taft and
D. V. Krogstad, J. Org. Chem., 2011, 76, 5061;
(b) T. Kobayashi, M. Nakashima, T. Hakogi, K. Tanaka and
S. Katsumura, Org. Lett., 2006, 8, 3809.
13 (a) J. E. Klijn and J. B. Engberts, Nature, 2005, 435, 746;
(b) S. Narayan, J. Muldoon, M. G. Finn, V. V. Fokin,
H. C. Kolb and K. B. Sharpless, Angew. Chem., Int. Ed.,
2005, 44, 3275; (c) B. H. Lipshutz and B. R. Taft, Org. Lett.,
2008, 10, 1329; (d) B. H. Lipshutz, D. W. Chung and
B. Rich, Org. Lett., 2008, 10, 3793; (e) T. Nishikata and
B. H. Lipshutz, Org. Lett., 2009, 11, 2377.
14 M. Dowlut, D. Mallik and M. G. Organ, Chem.–Eur. J., 2010,
16, 4279.
15 (a) A. Krasovskiy and B. H. Lipshutz, Org. Lett., 2011, 13,
3818; (b) G. P. Lu, K. R. Voigtritter, C. Cai and
B. H. Lipshutz, J. Org. Chem., 2012, 77, 3700.
Notes and references
1 C. C. Carin, J. Seechurn, M. O. Kitching, T. J. Colacot and
V. Snieckus, Angew. Chem., Int. Ed., 2012, 51, 5062.
2 (a) M. Kosugi, K. Sasazawa, Y. Shimizu and T. Migita,
Chem. Lett., 1977, 301; (b) D. Milstein and J. K. Stille, J. Am.
Chem. Soc., 1978, 100, 3636; (c) M. Kosugi and K. Fugami,
J. Organomet. Chem., 2002, 653, 50. For an updated review,
see: .Y. Pengand W.-D. Z. Li, Eur. J. Org. Chem., 2010, 6703,
and references therein.
3 (a) M. D. Shair, T. Y. Yoon, K. K. Mosny, T. C. Chou and
S. J. Danishefsky, J. Am. Chem. Soc., 1996, 118, 9509;
(b) P. Espinet and A. M. Echavarren, Angew. Chem., Int. Ed.,
2004, 43, 4704; (c) H. Fuwa, N. Kainuma, K. Tachibana and
M. Sasaki, J. Am. Chem. Soc., 2002, 124, 14983;
(d) J. H. Chang, H.-U. Kang, I.-H. Jung and C.-G. Cho, Org.
Lett., 2010, 12, 2016.
16 V. Farina and G. P. Roth, Tetrahedron Lett., 1991, 32, 4243.
17 R. Shen, T. Inoue, M. Forgac and J. A. Porco, J. Org. Chem.,
2005, 70, 3686.
4 (a) A. F. Littke and G. C. Fu, Angew. Chem., Int. Ed., 1999,
38, 2411; (b) S. P. H. Mee, V. Lee and J. E. Baldwin,
This journal is © The Royal Society of Chemistry 2013
Green Chem., 2013, 15, 105–109 | 109