Samarium triiodide-catalyzed formation of Mannich-type products by amidoalkylation of 1,3-dicarbonyl compounds

Article abstract of DOI:10.1080/00397910701569569

With samarium triiodide (SmI3) as a catalyst, the amidoalkylation of 1,3-dicarbonyl compounds with N-(1-benzotriazol-1-ylalkyl)amides proceeded readily under mild conditions to afford Mannich-type products in good to excellent yields. Copyright Taylor & F

Full text of DOI:10.1080/00397910701569569

This article was downloaded by: [Duke University Libraries]
On: 11 October 2014, At: 00:53
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office:
Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Synthetic Communications: An International
Journal for Rapid Communication of
Synthetic Organic Chemistry
Publication details, including instructions for authors and subscription
information:
http://www.tandfonline.com/loi/lsyc20
Samarium Triiodide–Catalyzed Formation of
Mannich‐Type Products by Amidoalkylation of
1,3‐Dicarbonyl Compounds
Xiaoxia Wang a , Hui Mao a , Yan Yu a , Xiudan Zhu a & Chunlan Zhu a
a Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces , College
of Chemistry and Life Sciences, Zhejiang Normal University , Jinhua, China
E-mail:
Published online: 19 Oct 2007.
To cite this article: Xiaoxia Wang , Hui Mao , Yan Yu , Xiudan Zhu & Chunlan Zhu (2007) Samarium
Triiodide–Catalyzed Formation of Mannich‐Type Products by Amidoalkylation of 1,3‐Dicarbonyl Compounds,
Synthetic Communications: An International Journal for Rapid Communication of Synthetic Organic Chemistry,
37:21, 3751-3758, DOI: 10.1080/00397910701569569
To link to this article: http://dx.doi.org/10.1080/00397910701569569
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”)
contained in the publications on our platform. However, Taylor & Francis, our agents, and our
licensors make no representations or warranties whatsoever as to the accuracy, completeness, or
suitability for any purpose of the Content. Any opinions and views expressed in this publication
are the opinions and views of the authors, and are not the views of or endorsed by Taylor &
Francis. The accuracy of the Content should not be relied upon and should be independently
verified with primary sources of information. Taylor and Francis shall not be liable for any
losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities
whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or
arising out of the use of the Content.
This article may be used for research, teaching, and private study purposes. Any substantial
or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or
distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use
can be found at http://www.tandfonline.com/page/terms-and-conditions

Synthetic Communicationsw, 37: 3751–3758, 2007
Copyright # Taylor & Francis Group, LLC
ISSN 0039-7911 print/1532-2432 online
DOI: 10.1080/00397910701569569
Samarium Triiodide–Catalyzed
Formation of Mannich-Type
Products by Amidoalkylation
of 1,3-Dicarbonyl Compounds
Xiaoxia Wang, Hui Mao, Yan Yu, Xiudan Zhu,
and Chunlan Zhu
Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces,
College of Chemistry and Life Sciences, Zhejiang Normal University,
Jinhua, China
Abstract: With samarium triiodide (SmI3) as a catalyst, the amidoalkylation of 1,3-
dicarbonyl compounds with N-(1-benzotriazol-1-ylalkyl)amides proceeded readily
under mild conditions to afford Mannich-type products in good to excellent yields.
Keywords: amidoalkylation, N-(1-benzotriazol-1-ylalkyl)amides, 1,3-dicarbonyl
compounds, Mannich-type products, SmI3
The Mannich reaction is among the most useful organic reactions because the
resulting b-amino compounds are either of biological and chemical import-
ance themselves or can be converted into a variety of other useful
compounds.[1]
In recent years, the Mannich reaction between dicarbonyl compounds and
N-acyl imines catalyzed by a Lewis base or Lewis acid to produce the poten-
tially useful b-amido dicarbonyl compounds has drawn intense interest. For
example, the asymmetric addition of b-ketoesters or malonates to acyl
Received in Japan April 13, 2007
Address correspondence to Xiaoxia Wang, Zhejiang Key Laboratory for Reactive
Chemistry on Solid Surfaces, College of Chemistry and Life Sciences, Zhejiang
Normal University, Jinhua 321004, China. E-mail: wangxiaoxia@zjnu.cn
3751

3752
X. Wang et al.
imines catalyzed by cinchona alkaloid[2] or cinchona alkaloid–derived
thiourea[3,4] was achieved with high ee and de values. Phosphorodiamidic
acid as a novel BrØnsted acid was also developed as an efficient catalyst
for the direct Mannich reaction between N-acyl imines and 1,3-dicarbonyl
compounds.[1c,5] Besides, enecarbamates were found to be good imine surro-
gates that underwent a Mannich reaction with 1,3-dicarbonyl compounds with
Cu(OTf)2 or Sc(OTf)3 as the catalyst.[6]
Despite this protocol for the preparation of amido-containing 1,3-dicar-
bonyl compounds, the amidoalkylation of CH acids with N-(1-
benzotriazol-1-ylalkyl)amides developed by the Katritzky group offered
an alternative route.[7] The introduction of N-(1-benzotriazol-1-ylalkyl)a-
mides has the advantages of being stable and readily available; however,
the use of excess AlCl3 as the catalyst therein was undesirable because of
the formation of a large amount of unnecessary aluminum-containing waste.
SmI3 as a mild Lewis acid has been found to catalyze a variety of
reactions such as Michael addition,[8] ring-opening of epoxides,[9] conden-
sation via enolate formation,[10] the transformation of aldehydes into acylals
and acetals, and the reverse deprotection.[11] In the course of our research
aimed at exploiting the application of SmI3 as an efficient Lewis acid in
organic synthesis, we have recently found that the b-amido dicarbonyl
compounds could be prepared readily from 1,3-dicarbonyl compounds and
N-(1-benzotriazol-1-ylalkyl)amides in the presence of a catalytic amount of
SmI3 (Scheme 1).
The reaction proceeded smoothly at room temperature in THF with
20 mol% of SmI3, and a series of amido-containing Mannich adducts were
prepared in this way with good to excellent yields. Table 1 summarizes the
scope and limitation of the reaction.
As described in Table 1, when R1 in the N-(1-benzotriazol-1-ylalkyl)
amides 1 was an aryl (entries 1–13), the corresponding Mannich adducts
were obtained with yields ranging from 67 to 92%, showing good generality.
The 1,3-dicarbonyl compounds 2 could be acetylacetone (entries 1, 5, 9, 12),
methyl or ethyl acetoacetate (entries 2, 3, 6, 7, 10, 11, 13), and diethyl
malonate (entries 4, 8). The reaction using methyl or ethyl acetoacetate
1
afforded high diastereoselectivities (84 to 89%) as determined by H NMR.
However, no reaction occurred when R1 was an alkyl (entry 14), and ethyl
Scheme 1.

Table 1. Amidoalkylation of 1,3-dicarbonyl compounds catalyzed by samarium triiodide
Entry
R1
R2
R3
Me-
R4
Me-
Products 3
Yields (%)a
De (%)b
1
2
3a
3b
3c
3d
3e
3f
83
90
82
87
70
91
80
65
80
85
86
—
87
89
—
—
87
89
—
—
87
89
Me-
Me-
EtO-
Me-
Me-
Me-
EtO-
Me-
Me-
Me-
MeO-
EtO-
EtO-
Me-
3
4
5
Me-
Me-
Me-
Me-
Me-
Me-
6
MeO-
EtO-
EtO-
Me-
7
3g
3h
3i
8
9
10
11
MeO-
MeO-
3j
3k
12
13
Me-
Me-
Me-
Me-
Me-
Me-
3l
67
92
—
84
MeO-
Me-
3m
c
14
15
n-Pr-
3n
4
—
—
—
c
—
aYields of pure isolated products.
1
bDetermined by H NMR analysis.
cNo reaction.

3754
X. Wang et al.
cyanoacetate also failed to undergo the nucleophilic substitution (Table 1,
entry 15).
Attempts were also made to extend the protocol for the preparation of
amino-containing Mannich adducts. 1-(Morpholino(phenyl)methyl)-benzo-
triazole 4 was therefore applied. The reaction between 4 and methyl acetoace-
tate resulted in rapid precipitation of light yellow solid plates, which were
1
characterized by H NMR, 13C NMR, and thermogravimetric analysis to be
a complex containing morpholine and samarium, but the expected product 5
was not detected (Scheme 2). The exact structure of the complex failed to
be ascertained because the single crystal could not be obtained after trying
various conditions. However, the complex obviously formed from the
cleavage of substrate 4, which liberated morpholine and then coordinated to
the samarium salts. The use of another amino-containing substrate 6 failed
also, where complicated products defied further analysis. It could be
concluded that SmI3 was not applicable for the Mannich-type reaction
between N-(1-benzotriazol-1-ylalkyl)amines and 1,3-dicarbonyl compounds.
In summary, SmI3 was found to be an efficient catalyst for the nucleophi-
lic substitution between N-(1-benzotriazol-1-ylalkyl)amides and 1,3-dicarbo-
nyl compounds, and the amido-containing Mannich-type products were
obtained with good yields and high diastereoselectivities. The reaction
provides a useful addition to the existing method for the preparation of
Mannich-type products.
EXPERIMENTAL
Tetrahydrofuran was distilled from sodium benzophenone immediately prior
1
to use. Melting points are uncorrected. H NMR (400-MHz) spectra were
recorded on a Bruker AV400 NMR instrument as DMSO-d6 or CDCl3
solutions using TMS as internal standard. Chemical shifts (d) are reported
in parts per million (ppm) and coupling constants J are given in hertz. IR
spectra were recorded in film or using KBr disks with a Nicolet Nexus 670
Scheme 2.

Amidoalkylation of 1,3-Dicarbonyl Compounds
3755
FT-IR spectrometer. Mass spectra were recorded on a HP 5989B MS
spectrometer (70 eV). Elemental analyses were performed on a Vario-ELIII
instrument. N-(1-Benzotriazol-1-ylalkyl)amides 1 were prepared according
to literature reports.[7,12]
General Procedure for the Preparation of b-Ketoesters
To samarium powder (0.03 g, 0.2 mmol) in a flask, anhydrous THF (10 mL) and
I2 (0.076 g, 0.3 mmol) were added. The mixture was stirred at rt for 1 h. To the
SmI3–THF suspension thus prepared, N-(1-benzotriazol-1-ylalkyl)amides 1
(1 mmol) and 1,3-dicarbonyl compounds 2 (1.1 mmol) were added. The
reaction mixture was stirred until the disappearance of 1 (usually within
10 h). Then the reaction was quenched with dilute hydrochloric acid
(0.1 mol/L, 3 mL) and extracted with diethyl ether (3 ꢀ 30 mL). The
combined extracts were washed with saturated Na2S2O3 solution, then with
brine, and were dried over anhydrous Na2SO4. Removal of the solvent under
reduced pressure and purification by preparative thin-layer chromatography
(TLC) on silica gel (eluent: ethyl acetate/cyclohexane 1:6) gave the
Mannich-type products 3.
Data
Compound 3a: White solid, mp 186–1888C. nmax(KBr)/cm21: 3358, 3061,
2919, 1724, 1700, 1641. dH(DMSO): 8.83 (d, J 8.8 Hz, 1H), 7.72–7.70
(m, 2H), 7.49–7.38 (m, 5H), 7.29 (t, J 7.2 Hz, 2H), 7.23–7.21 (m, 1H),
5.67 (dd, J 11.2, 8.8 Hz, 1H), 4.70 (d, J 11.2 Hz, 1H), 2.21 (s, 3H), 1.92
(s, 3H). m/z (%): 266 (Mþ 2 43, 18.99), 105 (100), 77 (46.35), 43 (37.17).
Anal. calcd. for C19H19NO3: C, 73.77; H, 6.19; N, 4.53. Found: C, 74.09;
H, 6.20; N, 4.51%.
Compound 3b: White solid, mp 161–1648C. nmax(KBr)/cm21: 3347, 3064,
2956, 1743, 1719, 1635. dH(CDCl3): 8.23 (br, d, J 8.8 Hz, 1H), 7.71–7.60
(m, 2H), 7.50–7.23 (m, 8H), 5.89 (dd, J 5.6, 8.8 Hz, 1H), 4.12 (d, J 5.6 Hz,
1H), 3.67 (s, 3H), 2.11 (s, 3H). 13C NMR (100 MHz, CDCl3): 188.1, 150.6.
145.1, 137.0, 134.6, 129.4, 128.8, 126.8, 122.1, 116.2, 112.6, 33.0, 21.2. m/z
(%): 282 (Mþ 2 43, 15.34), 105 (100), 77 (67.31), 43 (48.06). Anal.
calcd. for C19H19NO4: C, 70.14; H, 5.89; N, 4.31. Found: C, 69.86; H, 5.91;
N, 4.30%.
Compound 3c: White solid, mp 157–1608C. nmax(KBr)/cm21: 3361, 2984,
1735, 1717, 1636. dH(CDCl3): 8.21 (d, J 9.2 Hz, 1H), 7.72–7.70 (m, 2H),
7.49–7.21 (m, 8H), 5.87 (dd, J 5.6, 9.2 Hz, 1H), 4.21–4.11 (m, 2H), 4.10
(d, J 5.6 Hz, 1H), 2.11 (s, 3H), 1.2 (t, J 6.8 Hz, 3H). m/z (%): 339 (Mþ,

3756
X. Wang et al.
0.28), 296 (Mþ 2 43, 14.19), 105 (100), 77 (55.32), 43 (34.38). Anal. calcd. for
C20H21NO4: C, 70.78; H, 6.24; N, 4.13. Found: C, 70.95; H, 6.25; N, 4.12%.
Compound 3d: White solid, mp 106–1088C. nmax(KBr)/cm21: 3363, 2980,
1751, 1737, 1637. dH(CDCl3): 8.20 (d, J 9.2 Hz, 1H), 7.87–7.84 (m, 2H),
7.54–7.24 (m, 8H), 6.03 (dd, J 4.4, 9.2 Hz, 1H), 4.26–4.10 (m, 4H), 4.03
(d, J 4.4 Hz, 1H), 1.23 (t, J 7.2 Hz, 3H), 1.16 (t, J 7.2 Hz, 3H). m/z (%): 369
(Mþ, 0.79), 264 (Mþ 2 105, 50.25), 105 (100), 77 (57.94). Anal. calcd. for
C21H23NO5: C, 68.28; H, 6.28; N, 3.79. Found: C, 68.16; H, 6.29; N, 3.78%.
Compound 3e: White solid, mp 132–1348C. nmax(KBr)/cm21: 3359, 3065,
2965, 1670, 1650. dH(CDCl3): 7.33–7.22 (m, 5H), 6.96 (br, d, J 9.2 Hz,
1H), 5.85 (dd, J 5.6, 9.2 Hz, 1H), 4.28 (d, J 5.6 Hz, 1H), 2.27 (s, 3H), 2.08
(s, 3H), 2.00 (s, 3H). m/z (%): 248 (Mþ þ 1, 5.77), 204 (Mþ 2 43, 19.22),
162 (47.35), 148 (52.32), 106 (64.50) 43 (100). Anal. calcd. for
C14H17NO3: C, 68.00; H, 6.93; N, 5.66. Found: C, 68.11; H, 6.91; N, 5.64%.
Compound 3f: White solid, mp 145–1488C. nmax(KBr)/cm21: 3331, 2959,
1745, 1718, 1647. dH(CDCl3): 7.33–7.23 (m, 5H), 6.91 (d, J 9.2 Hz, 1H),
5.75 (dd, J 6.4, 9.2 Hz, 1H), 4.08 (d, J 6.4 Hz, 1H), 3.70 (s, 3H), 2.13
(s, 3H), 2.00 (s, 3H). m/z (%): 263 (Mþ, 0.32), 220 (Mþ 2 43, 25.35), 188
(18.20), 178 (18.42), 146 (45.13), 106 (68.67), 43 (100). Anal. calcd. for
C14H17NO4: C, 63.87; H, 6.51; N, 5.32. Found: C, 64.08; H, 6.50; N, 5.30%.
Compound 3g: White solid, mp 106–1098C. nmax(KBr)/cm21: 3343, 3065,
2984, 2938, 1734, 1716, 1652. dH(CDCl3): 7.32–7.22 (m, 5H), 6.92 (d, J
9.0 Hz, 1H), 5.75 (dd, J 6.0, 9.0 Hz, 1H), 4.21–4.11 (m, 2H), 4.06 (d, J
6.0 Hz, 1H), 2.14 (s, 3H), 1.99 (s, 3H), 1.20 (t, J 6.8 Hz, 3H). m/z (%): 277
(Mþ, 0.46), 234 (Mþ 2 43, 24.90), 188 (28.89), 146 (54.26), 106 (88.09),
43 (100). Anal. calcd. for C15H19NO4: C, 64.97; H, 6.91; N, 5.05. Found:
C, 65.18; H, 6.88; N, 5.04%.
Compound 3h: Viscous oil. nmax(KBr)/cm21: 3280, 3065, 2983, 1736, 1657.
dH(CDCl3): 7.38–7.23 (m, 6H), 5.81 (dd, J 4.4, 9.2 Hz, 1H), 4.21–4.04
(m, 4H), 3.91 (d, J 4.4 Hz, 1H), 2.03 (s, 3H), 1.24 (t, J 7.2 Hz, 3H), 1.12
(t, J 7.2 Hz, 3H). m/z (%): 308 (Mþ þ 1, 100), 264 (Mþ 2 43, 81.68), 148
(65.35), 106 (67.29), 43 (71.45). Anal. calcd. for C16H21NO5: C, 62.53; H,
6.89; N, 4.56. Found: C, 62.36; H, 6.91; N, 4.55%.
Compound 3i: White solid, mp 148–1508C. nmax(KBr)/cm21: 3300, 3038,
2922, 1721, 1700, 1642. dH(CDCl3): 7.14–7.09 (m, 4H), 6.90 (d, J 9.2 Hz,
1H), 5.80 (dd, J 6.0, 9.2 Hz, 1H), 4.26 (d, J 6.0 Hz, 1H), 2.30 (s, 3H), 2.24
(s, 3H), 2.08 (s, 3H), 1.98 (s, 3H). m/z (%): 261 (Mþ, 0.37), 218 (Mþ 2 43,
43.46), 176 (80.61), 120 (75.45), 43 (100). Anal. calcd. for C15H19NO3: C,
68.94; H, 7.33; N, 5.36. Found: C, 68.72; H, 7.35; N, 5.34%.

Amidoalkylation of 1,3-Dicarbonyl Compounds
3757
Compound 3j: White solid, mp 131–1338C. nmax(KBr)/cm21: 3334, 2953,
1746, 1719, 1648. dH(CDCl3): 7.16–7.10 (m, 4H), 6.83 (d, J 9.2 Hz, 1H),
5.71 (dd, J 6.0, 9.2 Hz, 1H), 4.05 (d, J 6.0 Hz, 1H), 3.69 (s, 3H), 2.30
(s, 3H), 2.14 (s, 3H), 1.99 (s, 3H). m/z (%): 277 (Mþ, 1.56), 234 (Mþ 2 43,
52.48), 202 (38.64), 192 (38.53), 160 (80.92), 120 (100), 43 (94.05). Anal.
calcd. for C15H19NO4: C, 64.97; H, 6.91; N, 5.05. Found: C, 65.06; H, 6.89;
S, 5.06%.
Compound 3k: White solid, mp 142–1448C. nmax(KBr)/cm21: 3348, 2954,
2837, 1739, 1717, 1637. dH(CDCl3): 7.80–7.76 (m, 3H), 7.52–7.41
(m, 3H), 7.26–7.24 (m, 2H), 6.84 (d, J 8.4 Hz, 2H), 5.88 (dd, J 4.8, 8.8 Hz,
1H), 4.17 (d, J 4.8 Hz, 1H), 3.76 (s, 3H), 3.70 (s, 3H), 2.17 (s, 3H). m/z
(%): 355 (Mþ, 0.96), 312 (Mþ-43, 12.16), 280 (8.29), 176 (19.27), 105
(100), 77 (53.48), 43 (24.91). Anal. calcd. for C20H21NO5: C, 67.59; H,
5.96; N, 3.94. Found: C, 67.81; H, 5.94; N, 3.93%.
Compound 3l: White solid, mp 153–1568C. nmax(KBr)/cm21: 3302, 3062,
2960, 2839, 1721, 1699, 1649. dH(CDCl3): 7.17 (d, J 8.8 Hz, 2H), 6.85–
6.82 (m, 3H), 5.78 (dd, J 6.0, 9.6 Hz, 1H), 4.24 (d, J 6.0 Hz, 1H), 3.77
(s, 3H), 2.24 (s, 3H), 2.09 (s, 3H), 1.98 (s, 3H). m/z (%): 277 (Mþ, 0.69),
312 (Mþ 2 43, 15.53), 192 (27.78), 136 (39.79), 43 (100). Anal. calcd. for
C15H19NO4: C, 64.97; H, 6.91; N, 5.05. Found: C, 64.78; H, 6. 92; N, 12.35%.
Compound 3m: White solid, mp 143–1458C. nmax(KBr)/cm21: 3340, 3007,
2962, 2840, 1740, 1716, 1648. dH(CDCl3): 7.19 (d, J 8.4 Hz, 2H), 6.84–6.81
(m, 3H), 5.68 (dd, J 6.4, 9.2 Hz, 1H), 4.03 (d, J 6.4 Hz, 1H), 3.76 (s, 3H), 3.68
(s, 3H), 2.15 (s, 3H), 1.98 (s, 3H). m/z (%): 293 (Mþ, 4.02), 250 (Mþ 2 43,
37.11), 218 (24.61), 208 (28.41), 176 (54.16), 136 (87.09), 43 (100). Anal.
calcd. for C15H19NO5: C, 61.42; H, 6.53; N, 4.78. Found: C, 61.63; H, 6.52;
N, 4.77%.
ACKNOWLEDGMENTS
We are grateful to the Natural Science Foundation of Zhejiang Province
(Project No. Y405035) for financial support.
REFERENCES
¯
1. (a) Hirose, T.; Sunazuka, T.; Yamamoto, D.; Kaji, E.; Omura, S. Synthetic appli-
cations of a three-component Mannich reaction. Total synthesis of IL-6 inhibitor
(þ)-madindoline A and B. Tetrahedron Lett. 2006, 47 (58), 6761–6764;
(b) List, B.; Pojarliev, P.; Biller, W. T.; Martin, H. J. The proline-catalyzed

3758
X. Wang et al.
direct asymmetric three-component Mannich reaction: Scope, optimization, and
application to the highly enantioselective synthesis of 1,2-amino alcohols.
J. Am. Chem. Soc. 2002, 124 (5), 827–833; (c) Uraguchi, D.; Terada, M. Chiral
Brønsted acid–catalyzed direct Mannich reactions via electrophilic activation.
J. Am. Chem. Soc. 2004, 126 (17), 5356–5357.
2. Lou, S.; Taoka, B. M.; Ting, A.; Schaus, S. E. Asymmetric Mannich reactions of
b-keto esters with acyl imines catalyzed by cinchona alkaloids. J. Am. Chem. Soc.
2005, 127 (32), 11256–11257.
3. Bode, C. M.; Ting, A.; Schaus, S. E. A general organic catalyst for asymmetric
addition of stabilized nucleophiles to acyl imines. Tetrahedron 2006, 62 (49),
11499–11505.
4. Song, J.; Wang, Y.; Deng, L. The Mannich reaction of malonates with simple
imines catalyzed by bifunctional cinchona alkaloids: Enantioselective synthesis
of b-amino acids. J. Am. Chem. Soc. 2006, 128 (18), 6048–6049.
5. Terada, M.; Sorimachi, K.; Uraguchi, D. Phosphorodiamidic acid as a novel struc-
tural motif of Brønsted acid catalysts for direct Mannich reaction of N-acyl imines
with 1,3-dicarbonyl compounds. Synlett. 2006, 1, 133–136.
6. Kobayashi, S.; Gustafsson, T.; Shimizu, Y.; Kiyohara, H.; Matsubara, R. Enecar-
bamates as imine surrogates: nucleophilic addition of 1,3-dicarbonyl compounds
to enecarbamates. Org. Lett. 2006, 8 (21), 4923–4925.
7. Katritzky, A. R.; Pernak, J.; Fan, W. Q.; Saczewski, F. N-(1-Benzotriazol-1-ylalkyl)
amides, versatile alpha-amidoalkylation reagents: Amidoalkylation of CH acids.
J. Org. Chem. 1991, 56 (14), 4439–4443.
8. (a) Zou, X.; Wang, X.; Cheng, C.; Kong, L.; Mao, H. Highly regioselective
Friedel–Crafts alkylation of indoles with a,b-unsaturated N-acylbenzotriazoles.
Tetrahedron Lett. 2006, 47 (22), 3767–3771; (b) Zhan, Z. P.; Lang, K.
Microwave-accelerated samarium triiodide–catalyzed conjugate addition of
indoles with electron-deficient olefins. Synlett. 2005, 10, 1551–1554.
9. (a) Kwon, D. W.; Cho, M. S.; Kim, Y. H. Samarium(III) iodide complex catalyzed
regioselective cleavage of epoxides to iodohydrins: Tandem epoxide opening–
iodocyclization. Synlett. 2003, 7, 959–946.
10. Yu, Y.; Lin, R.; Zhang, Y. Carbon–carbon double bond formation between
a-haloketones and aldehydes promoted by samarium triiodide. Tetrahedron Lett.
1993, 34 (28), 4547–4550.
11. Wang, X.; Zhang, Y. Formation of a,a0-bis(substituted benzylidene)cycloalka-
nones from masked aldehydes promoted by samarium(III) triiodide. Chin.
Chem. Lett. 2004, 15 (5), 511–514, and the references cited therein.
12. (a) Katritzky, A. R.; Fang, Y.; Silina, A. Preparation of b-amido ketones and
aldehydes via amidoalkylation of eanmines, enol silyl ethers, and vinyl ethers.
´
J. Org. Chem. 1999, 64 (20), 7622–7624; (b) Barluenga, J.; Fernandez-
´
´
Simon, J. L.; Concellon, J. M.; Yus, M. The chemistry of benzotriazoles, part 8:
A novel two-step procedure for the N-alkylation of amides. J. Chem. Soc., Perkin
Trans. 1, 1988, 2339–2344.