POCl3 promoted metal-free synthesis of tertiary amides by coupling of carboxylic acids and N,N-disubstituted formamides

Article abstract of DOI:10.1080/10426507.2018.1539991

Herein we report a robust and synthetically useful catalyst-free amination methodology by the coupling of carboxylic acids and N-substituted formamides using POCl₃ as a promoter. Versatile amides with a wide array of substituent groups were prepared within only 1 h in good to excellent yields. And even multi-substituted aromatic carboxylic acids could give the desired products with satisfactory results.

Full text of DOI:10.1080/10426507.2018.1539991

Phosphorus, Sulfur, and Silicon and the Related Elements
ISSN: 1042-6507 (Print) 1563-5325 (Online) Journal homepage: https://www.tandfonline.com/loi/gpss20
POCl3 promoted metal-free synthesis of tertiary
amides by coupling of carboxylic acids and N,N-
disubstituted formamides
Xiaojing Bi, Junchen Li, Enxue Shi, Yu Li, Ying Liu, Hongmei Wang & Junhua
Xiao
To cite this article: Xiaojing Bi, Junchen Li, Enxue Shi, Yu Li, Ying Liu, Hongmei Wang & Junhua
Xiao (2019): POCl3 promoted metal-free synthesis of tertiary amides by coupling of carboxylic acids
and N,N-disubstituted formamides, Phosphorus, Sulfur, and Silicon and the Related Elements, DOI:
10.1080/10426507.2018.1539991
To link to this article: https://doi.org/10.1080/10426507.2018.1539991
View supplementary material
Published online: 20 Feb 2019.
Submit your article to this journal
Article views: 5
View Crossmark data
Full Terms & Conditions of access and use can be found at
https://www.tandfonline.com/action/journalInformation?journalCode=gpss20

PHOSPHORUS, SULFUR, AND SILICON AND THE RELATED ELEMENTS
https://doi.org/10.1080/10426507.2018.1539991
POCl3 promoted metal-free synthesis of tertiary amides by coupling of
carboxylic acids and N,N-disubstituted formamides
Xiaojing Bi, Junchen Li, Enxue Shi, Yu Li, Ying Liu, Hongmei Wang, and Junhua Xiao
State Key Laboratory of NBC Protection for Civilian, Beijing, PR China
ABSTRACT
ARTICLE HISTORY
Received 7 July 2018
Accepted 21 October 2018
Herein we report a robust and synthetically useful catalyst-free amination methodology by the
coupling of carboxylic acids and N-substituted formamides using POCl3 as a promoter. Versatile
amides with a wide array of substituent groups were prepared within only 1 h in good to excellent
yields. And even multi-substituted aromatic carboxylic acids could give the desired products with
satisfactory results.
KEYWORDS
Amide; metal-free; POCl3;
carboxylic acid; N-
substituted formamides
GRAPHICAL ABSTRACT
Introduction
with amines in the presence of activating agents (Scheme
1f).[4j] In addition to this, new approach to amide was con-
tinuously reported recently.[4k] In Hosoi’s pioneering work
about the Pd-catalyzed aminocarbonylation of halides with
DMF (Scheme 1a),[3h] POCl3 was found to play a vital role
Within the field of organic chemistry, the amide moiety is
central to many extensively used natural products, pharma-
ceuticals, and peptides.[1] Owing to the significance of
amides, diverse synthetic methods for this preparation have
been reported in the past decades.[2] Recently, aminocarbo-
nylation of aryl halides with N-substituted formamides has
become a mainstay transformation in organic synthesis.[3]
Hosoi discovered an aminocarbonylation reaction of aryl
and alkyl halides employing DMF as the amide source,[3h]
in which POCl3 played an important role and participated
in the reaction to form a Vilsmeier-type intermediate
(Scheme 1a). Copper-catalyzed decarboxylative coupling of
aryl-carboxylic acids with DMF was also successfully
achieved in combination with peroxides (Scheme 1b).[3j–3k]
Wang revealed that I2 could effectively mediate the direct
amidation of benzyl alcohols and amines with N-substituted
formamides using TBHP as oxidant in good to excellent
yields (Scheme 1c).[4a] A new method for the synthesis of
amides from benzyl alcohol, benzaldehyde and benzylamine
were reported subsequently.[4b–4g] Very recently, Liu re-
ported a remarkable room temperature reaction catalyzed by
Ru and visible-light using potassium thioacids as acylation
reagent (Scheme 1d).[4i] Another metal-free method use car-
boxylic acids as substrate was reported by Kumagai, good
yields were obtained in the presence of thionyl chloride
(Scheme 1e).[3m] Of course, the most common method for
in the formation of
a
Vilsmeier-type intermediate.[5]
Inspired by this strategy, we hypothesized that amides might
be prepared via decarboxylative coupling of carboxylic acids
with formamides under specific experimental conditions. To
our delight, we found that amides were successfully obtained
when carboxylic acids instead of aryl halides in the similar
reaction conditions. More significant, this transformation
occurred well in the absence of Pd catalyst and ligand,[3h]
suggesting that POCl3 might be a key factor in this reaction.
Encouraged by these results, herein we presented a POCl3-
mediated metal-free synthesis of amides by coupling of car-
boxylic acids with N-substituted formamides (Scheme 1g).
Results and discussion
We began our investigation using benzoic acid 1a and DMF
2a as the model reaction (Table 1). Evaluation of the POCl3
loading effect revealed that 1 equivalent of POCl3 was most
suitable for this reaction (entry 2). Reducing or increasing
the amount of POCl3 both resulted in lower yields (entries
1, 3–4). To further improve the reaction, we changed the
reaction time. A shorter time, less than 1 h was found to
lead to a lower yield due to the low conversion of benzoic
the preparation of amides is the coupling of carboxylic acids acid (entry 5). Prolonging the reaction time from 1 to 2 h or
CONTACT Junhua Xiao
xiao.junhua@pku.edu.cn
Supplemental data for this article can be accessed on the publisher’s website at https://doi.org/10.1080/10426507.2018.1539991.
ß 2019 Taylor & Francis Group, LLC

2
X. BI ET AL.
With above optimized conditions in hand, we next
applied this new method to various carboxylic acids and N-
substituted formamides to examine the efficiency and scope
of the new approach (Table 2). We found that arylcarboxylic
acids containing both electron-donating (3a–3c) and elec-
tron-withdrawing (3e–3k) substituents afforded good yields.
As outlined in Table 2, this transformation is tolerant to
aromatic coupling partners that incorporate a wide range of
functional groups, including OH (3d), halides (3f, 3h), and
NO2 (3i–3k). Whereas, 4-OH-benzoic acid gave a lower
yield of 3d because parts of the substrate participated in
Vilsmeier-Haack reaction in this reaction conditions
(Scheme 2).[6]
Steric hindrance in terms of ortho-substitution with Cl, I,
CF3, and NO2 were tolerated well under the optimal condi-
tions (Table 2, 3f–3i). Heteraromatic carboxylic acids, such
as nicotinic acid and its two homologous compounds also
proceeded to give the corresponding amides in good yields
(3m–3o). This concept could be further applied to the cou-
pling of aliphatic carboxylic acids to provide the amidation
products in 83-96% yields (3p–3q). Moreover, other types of
N-substituted formamides such as N-formylmorpholine and
N,N-dibutylformamide were compatible under this reaction
conditions (3r–3s).
Moreover, this transformation is not limited to mono-
substituted carboxylic acids, but can also be applied to
multi-substituted benzoic acids in high yields (Table 3). In
our previous work of Ru-catalyzed direct amination of car-
boxylic acids, the multi- substituted benzoic acids were not
very successful, and low yields were obtained.[7] Notably, in
this POCl3-promoted reaction, even sterically hindered sub-
strates of ortho-nitrobenzoic acids with two or more sub-
stituent groups were transformed to the corresponding
products, demonstrating that a steric effect of the ortho-sub-
stituent might not be obvious.
Scheme 1. Synthetic approaches of amides.
Table 1. Optimization of reaction conditions.a,b
During the amidation of benzoic acid with N,N-dibutyl-
formamide, benzoyl chloride could be observed as the inter-
mediate through GC-MS. A control experiment showed that
benzoyl chloride could also give the corresponding amide in
a good yield without any additives (Scheme 3), which pro-
vides another effective method for the synthesis of amides
from N-substituted formamides.
In order to provide insight into the reaction mechanism,
we first set out a 13C-labeling experiment to determine the
source of the carbonyl group of the amination reaction
(Scheme 4). Both GC-MS and 13C NMR results showed that
carboxylic acid is the carbonyl contributor.
On the basis of above results, a probable mechanism was
speculated in Scheme 5. The combination of DMF and
POCl3 is known to form a Vilsmeier reagent (I), which
could act as a chlorination reagent to converse carboxylic
acid into acyl chloride (II). And we hold the opinion that
some of II were probably transformed through the chlorina-
tion of POCl3. It has been established that DMF can decom-
pose to dimethylamine and carbon monoxide when heating
Entry
POCl3 (eq.)
Temp. (ꢀC)
Time (h)
Yield (%)b
1
2
3
4
5
6
7
8
0.5
1
2
3
1
1
1
1
1
120
120
120
120
120
120
120
80
1
1
1
1
0.7
2
7
2
35
96
93
54
80
96
97
15
19
72
80
9
100
110
135
2
2
2
10
11
1
1
aReaction conditions: Benzoic acid 1a (0.3 mmol), 2a (2 mL).
bDetermined by GC-MS with area normalization method by using mesitylene
as the internal standard.
even 7 h could not further ameliorate the reaction efficiency
(entries 6–7). Temperature screening experiments showed
that the best result could be obtained when the reaction was to the boiling point or in the presence of some acidic or
carried out at 120 ꢀC (entries 8–11). basic materials.[8]

PHOSPHORUS, SULFUR, AND SILICON AND THE RELATED ELEMENTS
3
Table 2. Scope of substituted carboxylic acids and formamides.a,b
Table 3. Scope of multisubtituted benzoicacids.a,b
aReaction conditions: Carboxylic acid 1 (0.3mmol), 2a (2 mL), POCl3(0.3mmol),
120 ꢀC, 1 h.
bIsolated yield.
aReaction conditions: Carboxylic acid 1 (0.3 mmol), 2 (2 mL), POCl3 (0.3 mmol),
120 ꢀC, 1 h.
bIsolated yield.
Scheme 3. Control experiment.
Scheme 2. Vilsmeier-Haack reaction.
Conclusions
Subsequently, the newly formed dimethylamine and acyl
chloride (II) reacted to give the desired amide product.
The control experiment and proposed mechanism suggest
that other reagents including Cl might also be effective in
this amidation reaction. We then screened several chlorating
agents and found that phosphoryl chloride (Table 4, entries
1–3) and phosphonic chloride (Table 4, entry 4) afforded
the desired amides with 99% yield, and SOCl2 gave a yield
of 95%, but other chlorating reagents such as DCDMH and
trichloroisocyanuric acid exhibited relatively lower activities
in this reaction. And the same effect was achieved by the
scale up reaction (Table 4, entry 2).
In conclusion, we have developed a highly efficient approach
for the synthesis of amides with the assistance of POCl3.
Mono-substituted benzoic acids with electron-rich and elec-
tron-deficient groups, as well as disubstituted benzoic acids
or even multi-substituted benzoic acids reacted well under
the optimized conditions to give the corresponding amides
in good to excellent yields. Compared with former reports,
our strategy had shorter reaction time and higher yields.
This efficient synthetic methodology is expected to find
more applications in the synthesis of nature products
and peptides.

4
X. BI ET AL.
dried with MgSO4 for 24 h. The solution was evaporated
under reduced pressure and the crude product was purified
by column chromatography (silica gel, n-hexane-EtOAc,
1:1). The Supplemental Materials contains sample 1H and
13C NMR spectra for the products 3 and 4 (Figures S1–S63).
Scheme 4. Carbon labeling experiment.
References
[1] (a) Costall, B.; Sui-Chun, Hui, G.; Naylor, R. J. Differential
Actions of Substituted Benzamides on Pre- and Postsynaptic
Dopamine Receptor Mechanisms in the Nucleus Accumbens. J.
Pharm. Pharmacol. 1980, 32, 594–596. doi:10.1111/j.2042-
7158.1980.tb13009.x. (b) Florvall, L.; Oegren, S. O. Potential
Neuroleptic Agents. 2, 6-Dialkoxybenzamide Derivatives with
Potent Dopamine Receptor Blocking Activities. J. Med. Chem.
1982, 25, 1280–1286. doi:10.1021/jm00353a003. (c) Pitzer, J.;
Steiner, K. Amides in Nature and Biocatalysis. J. Biotechnol.
2016, 235, 32–46. doi:10.1016/j.jbiotec.2016.03.023.
[2] (a) de Figueiredo, R. M.; Suppo, J.-S.; Campagne, J.-M.
Nonclassical Routes for Amide Bond Formation. Chem. Rev.
2016, 116, 12029–12122. doi:10.1021/acs. chemrev.6b00237. (b)
Dunetz, J. R.; Magano, J.; Weisenburger, G. A. Large-Scale,
Applications of Amide Coupling Reagents for the Synthesis of
Pharmaceuticals. Org. Process Res. Dev. 2016, 20, 140–177. doi:
ꢀ
10.1021/op500305s. (c) Ojeda-Porras, A.; Gamba-Sanchez, D.
Recent Developments in Amide Synthesis Using Nonactivated
Starting Materials. J. Org. Chem. 2016, 81, 11548–11555. doi:
10.1021/acs.joc.6b02358. (d) Bannwart, L.; Abele, S.; Tortoioli,
S. Metal-Free Amidation of Acids with Formamides and T3P.
Synthesis 2016, 48, 2069–2078. doi:10.1055/s-0035-1561427. (e)
Bode, J. W.; Fox, R. M.; Baucom, K. D. Chemoselective Amide
Ligations by Decarboxylative Condensations of N-
Alkylhydroxylamines and a-Ketoacids. Angew. Chem. Int. Ed.
2006, 45, 1248–1252. doi:10.1002/anie.200503991. (f) Ghosh, S.;
Jana, C. K. Aminofluorene-Mediated Biomimetic Domino
Amination–Oxygenation of Aldehydes to Amides. Org. Lett.
2016, 18, 5788–5791. doi:10.1021/acs.orglett.6b02465. (g)
Schwieter, K. E.; Johnston, J.; N. A One-Pot Amidation of
Primary Nitroalkanes. Chem. Commun. 2016, 52, 152–155. doi:
10.1039/c5cc08415f. (h) Kuang, Z.; Li, B.; Song, Q. Cu/Pd
Cooperatively Catalyzed Tandem Intramolecular anti-
Markovnikov Hydroarylation of Unsaturated Amides: facile
Construction of 3,4-Dihydroquinolinones via Borylation/
Intramolecular C(sp3)-C(sp2) Cross Coupling. Chem. Commun.
2018, 54, 34–37. doi:10.1039/C7CC07180A. (i) Kumar, A.;
Espinosa-Jalapa, N. A.; Leitus, G.; Diskin-Posner, Y.; Avram, L.;
Milstein, D. Direct Synthesis of Amides by Dehydrogenative
Coupling of Amines with Either Alcohols or Esters: Manganese
Pincer Complex as Catalyst. Angew. Chem. Int. Ed. 2017, 56,
14992–14996. doi:10.1002/ange.201709180.
Scheme 5. Proposed mechanism.
Table 4. Different chloratingagents in this reaction.a,b
Entry
Chlorating agents（1 eq.）
Yield (%)
1
POCl3
POCl3
PCl3
>99%
>99%
>99%
>99%
95
2c
3
4
5
6
EtPOCl2
SOCl2
DCDMHd
25
28
Trichloroisocyanuric acid
aReaction conditions: benzoic acid (0.3 mmol), DMF (2 mL), 1 h.
bDetermined by GC-MS with area normalization method by using mesitylene
as the internal standard.
cBenzoic acid (10 mmol), DMF (3 mL), 1 h.
dDCDMH was the abbreviation of 1,3-dichloro-5,5-dimethylhydantoin.
[3] (a) Mane, R. S.; Bhanage, B. M. Pd/C-Catalyzed
Aminocarbonylation of Aryl Iodides via Oxidative C–N Bond
Activation of Tertiary Amines to Tertiary Amides. J. Org.
Chem. 2016, 81, 1223–1228. doi:10.1021/acs.joc. 5b02385. (b)
Iranpoor, N.; Firouzabadi, H.; Motevalli, S. Silicadiphenyl
Phosphinite (SDPP)/Pd (0) Nanocatalyst for Efficient
Aminocarbonylation of Aryl Halides with POCl3 and DMF. J.
Mol. Catal. A: Chem. 2012, 355, 69–74. doi:10.1016/j.mol-
cata.2011.10.021. (c) Sawant, D. N.; Wagh, Y. S.; Bhatte, K. D.;
Bhanage, B. M. Palladium-Catalyzed Carbon-Monoxide-Free
Aminocarbonylation of Aryl Halides Using N-Substituted
Formamides as an Amide Source. J. Org. Chem. 2011, 76,
5489–5494. doi:10.1021/jo200754v. (d) Sawant, D. N.; Wagh,
Y. S.; Tambade, P. J.; Bhatte, K. D.; Bhanage, B. M. Cyanides-
Free Cyanation of Aryl Halides Using Formamide. Adv. Synth.
Catal. 2011, 353, 781–787. doi:10.1002/adsc.201000807. (e)
Tambade, P. J.; Patil, Y. P.; Bhanushali, M. J.; Bhanage, B. M.
Pd/C: An Efficient, Heterogeneous and Reusable Catalyst for
Experimental
1H and 13C NMR spectra were recorded on Bruker Advance
300 MHz in CDCl3. GC-MS spectra were measured at
Thermo Polaris Q GC-MS instrument. All the chemicals
were commercially available and used without further purifi-
cation. Amide Synthesis: Carboxylic acids (0.3 mmol), POCl3
(1 equiv.) and N-substituted formamides (2 mL) were mixed
in a 20 mL tube. After tightening the cap, the mixture was
stirred at 120 ꢀC for 1 h and then cooled to room tempera-
ture and a saturated solution of 10 mL Na2CO3 was added.
Then the solution was extracted with ethyl acetate
(3 Â 10 mL), and the organic layers were combined and

PHOSPHORUS, SULFUR, AND SILICON AND THE RELATED ELEMENTS
5
Carbon Monoxide-Free Aminocarbonylation of Aryl Iodides.
Tetrahedron Lett. 2008, 49, 2221–2224. doi:10.1016/j.tet-
let.2008.02.049. (f) Ju, J.; Jeong, M.; Moon, J.; Hyun, M. J.; Lee,
Magnetic Carbon Nanotubes (MagCNTs@SiO2)-Immobilized
imine-Cu(I). Appl. Organomet. Chem. 2014, 28, 101–108. doi:
10.1002/aoc.3087. (g) Zhang, L.; Wang, W.; Wang, A.; Cui, Y.;
Huang, Y.; Zhang, T. Aerobic Oxidative Coupling of Alcohols
and Amines over Au-Pd/Resin in Water: Au/Pd Molar Ratios
Switch the Reaction Pathways to Amides or Imines. Green
Chem. 2013, 15, 2680–2684. doi:10.1039/C3GC41117F. (i) Liu,
H.; Zhao, L.; Yuan, Y.; Xu, Z.; Chen, K.; Qiu, S.; Tan, H.
Potassium Thioacids Mediated Selective Amide and Peptide
Constructions Enabled by Visible Light Photoredox Catalysis.
ACS Catal. 2016, 6, 1732–1736. doi:10.1021/acscatal.5b02943.
(j) Valeur, E.; Bradley, M. Amide Bond Formation: Beyond the
Myth of Coupling Reagents. Chem. Soc. Rev. 2009, 38, 606–631.
doi:10.1039/B701677H. (k) Fu, R.; Yang, Y.; Zhang, J.; Shao, J.;
Xia, X.; Ma, Y.; Yuan, R. Direct Oxidative Amidation of
Aldehydes with Amines Catalyzed by Heteropolyanion-Based
S. Aminocarbonylation of Aryl Halides Using
a Nickel
Phosphite Catalytic System. Org. Lett. 2007, 9, 4615–4618. doi:
€
10.1021/ol702058e. (g) Papp, M.; Skoda-Foldes, R. Phosphine-
Free Double Carbonylation of Iodobenzene in the Presence of
Reusable Supported Palladium Catalysts. J. Mol. Catal. A:
Chem. 2013, 378, 193–199. doi:10.1016/j.molcata.2013.06.002.
(h) Hosoi, K.; Nozaki, K.; Hiyama, T. Carbon Monoxide Free
Aminocarbonylation of Aryl and Alkenyl Iodides Using DMF
as an Amide Source. Org. Lett. 2002, 4, 2849–2851. doi:10.1021/
ol026236k. (i) Kumar, P. S.; Kumar, G. S.; Kumar, R. A.;
Reddy, N. V.; Rajender Reddy, K. Copper-Catalyzed Oxidative
Coupling of Carboxylic Acids with N,N-Dialkylformamides: An
Approach to the Synthesis of Amides. Eur. J. Org. Chem. 2013,
7, 1218–1222. doi:10.1002/ejoc.201201544. (j) Liu, H.-Q.; Liu, J.;
Zhang, Y.-H.; Shao, C.-D.; Yu, J.-X. Copper-Catalyzed Amide
Bond Formation from Formamides and Carboxylic Acids. Chin.
Chem. Lett. 2015, 26, 11–14. doi:10.1016/j.cclet.2014.09.007. (k)
Priyadarshini, S.; Joseph, P. J. A.; Kantam, M. L. Copper
Catalyzed Cross-Coupling Reactions of Carboxylic Acids: An
Expedient Route to Amides, 5-Substituted Gamma-Lactams and
Alpha-Acyloxy Esters. RSC Adv. 2013, 3, 18283–18287. doi:
10.1039/C3RA41000E. (l) Xie, Y.-X.; Song, R.-J.; Yang, X.-H.;
Xiang, J.-N.; Li, J.-H. Copper-Catalyzed Amidation of Acids
Using Formamides as the Amine Source. Eur. J. Org. Chem.
2013, 25, 5737–5742. doi:10.1002/ejoc.201300543. (m) Kumagai,
T.; Anki, T.; Ebi, T.; Konishi, A.; Matsumoto, K.; Kurata, H.;
Kawase, T. An Effective Synthesis of N,N-Dimethylamides from
Carboxylic Acids and a New Route from N,N-Dimethylamides
to 1,2-Diaryl-1,2-Diketones. Tetrahedron 2010, 66, 8968–8973.
doi:10.1016/j.tet.2010.09.037.
Ionic Liquids under Solvent-Free Conditions via
a Dual-
Catalysis Process. Org. Biomol. Chem. 2016, 14, 1784–1793. doi:
10.1039/C5OB02376A.
ꢀ
[5] (a) Gooßen, L. J.; Rodrıguez, N.; Gooßen, K.; Carboxylic Acids
as Substrates in Homogeneous Catalysis. Angew. Chem. Int. Ed.
2008, 4. 3100–3120. doi:10.1002/anie.200704782. (b) Rodriguez,
N.; Goossen, L. Decarboxylative Coupling Reactions: A Modern
Strategy for C–C-Bond Formation. J. Chem. Soc. Rev. 2011, 40,
5030–5048. doi:10.1039/C1CS15093F. (c) Shang, R.; Liu, L.
Transition Metal-Catalyzed Decarboxylative Cross-Coupling
Reactions. Sci. China Chem. 2011, 54, 1670–1687. doi:10.1007/
s11426-011-4381-0. (d) Dzik, W. I.; Lange, P. P.; Gooßen, L. J.
Carboxylates as Sources of Carbon Nucleophiles and
Electrophiles:
comparison
of
Decarboxylative
and
Decarbonylative Pathways. Chem. Sci. 2012, 3, 2671–2678. doi:
10.1039/C2SC20312J.
Decarboxylative
(e)
Cornella,
J.;
Larrosa,
Bond-Forming
I.
Carbon-Carbon
[4] (a) Gao, L.; Tang, H.; Wang, Z. Oxidative Coupling of
Methylamine with an Aminyl Radical: direct Amidation
Catalyzed by I 2/TBHP with HCl. Chem. Commun. 2014, 50,
4085–4088. doi:10.1039/C4CC00621F. (b) Baba, H.; Moriyama,
K.; Togo, H. Preparation of N,N-Dimethyl Aromatic Amides
from Aromatic Aldehydes with Dimethylamine and Iodine
Reagents. Synlett 2012, 23, 1175–1180. doi:10.1055/s-0031-
1290659. (c) Ghosh, S. C.; Ngiam, J. S. Y.; Seayad, A. M.; Tuan,
D. T.; Chai, C. L. L.; Chen, A. Copper-Catalyzed Oxidative
Amidation of Aldehydes with Amine Salts: Synthesis of
Primary, Secondary, and Tertiary Amides. J. Org. Chem. 2012,
77, 8007–8015. doi:10.1021/jo301252c. (d) Huang, H.; Yuan, G.;
Li, X.; Jiang, H. Electrochemical Synthesis of Amides: direct
Transformation of Methyl Ketones with Formamides.
Tetrahedron Lett. 2013, 54, 7156–7159. doi:10.1016/j.tet-
let.2013.10.101. (e) Li, H.; Xie, J.; Xue, Q.; Cheng, Y.; Zhu, C.
Metal-Free n-Bu4NI-Catalyzed Direct Synthesis of Amides from
Alcohols and N,N-Disubstituted Formamides. Tetrahedron Lett.
2012, 53, 6479–6482. doi:10.1016/j.tetlet.2012.09.039. (f) Saberi,
D.; Heydari, A. Oxidative Amidation of Aromatic Aldehydes
with Amine Hydrochloride Salts Catalyzed by Silica-Coated
Transformations of (hetero) Aromatic Carboxylic Acids.
Synthesis 2012, 44, 653–676. doi:10.1055/s-0031-1289686. (f)
ꢀ
Gooßen, L. J.; Gooßen, K.; Rodrıguez, N.; Blanchot, M.; Linder,
C.; Zimmermann, B. New Catalytic Transformations of
Carboxylic Acids. Pure Appl. Chem. 2008, 80, 1725–1733. doi:
10.1351/pac200880081725. (g) Hosoi, K.; Nozaki, K.; Hiyama,
T. Carbon Monoxide Free Aminocarbonylation of Aryl and
Alkenyl Iodides Using DMF as an Amide Source. Org. Lett.
2002, 4, 2849–2851. doi:10.1021/ol026236k.
ꢀ
[6] Ku€rti, L.; Czako, B. Strategic Applications of Named Reactions
in Organic Synthesis; Elsevier Inc.: Amsterdam, 2005.
[7] Bi, X.; Li, J.; Shi, E.; Wang, H.; Gao, R.; Xiao, J. Ru-Catalyzed
Direct Amidation of Carboxylic Acids with N-Substituted
Formamides. Tetrahedron 2016, 72, 8210–8214. doi:10.1016/
j.tet.2016.10.043.
[8] (a) Ding, S.; Jiao, N.; N,N-Dimethylformamide: A Multipurpose
Building Block. Angew. Chem. Int. Ed. 2012, 51, 9226–9237.
doi:10.1002/anie.201200859.
(b)
Muzart,
J.
N,N-
Dimethylformamide: much More than a Solvent. Tetrahedron
2009, 65, 8313–8323. doi:10.1016/j.tet.2009.06.091