Shashikant U. Dighe and Sanjay Batra
UPDATES
1
H NMR spectrum of the reaction mixture (B) was Council of Scientific and Industrial Research, New Delhi.
The authors acknowledge the SAIF Division of CSIR-CDRI
compared with that of the starting alkyne (A), prod-
uct (D) and commercial CH I (E). As we noticed
minor deviations in the chemical shift of the signal for
CH I as compared to its authentic sample we record-
for providing the spectroscopic and analytical data. This
work was carried out from the grant to SB under the CSIR-
Network project BSC0014.
2
2
2
2
ed another spectrum of a reaction mixture doped with
CH I (C). Herein we observed only one signal for
2
2
the CH I which implied that the minor shift may References
2
2
have been due to the mixture of reagents. Simultane-
ously H O reacts with NH I to liberate NH OH and
HOI that acts as source of I .
[
1] For reviews on the reactions of alkynes, see: a) G.
Zeni, R. C. Larock, Chem. Rev. 2004, 104, 2285–2310;
b) T. E. Muller, K. C. Hultzsch, M. Yus, F. Foubelo, M.
Tada, Chem. Rev. 2008, 108, 3795–3892; c) M. C. Willis,
Chem. Rev. 2010, 110, 725–748; d) B. Godoi, R. F. Schu-
macher, G. Zeni, Chem. Rev. 2011, 111, 2937–2980;
e) K. Gilmore, I. V. Alabugin, Chem. Rev. 2011, 111,
6513–6556; f) U. Wille, Chem. Rev. 2013, 113, 813–853;
g) R. Salvio, M. Moliterno, M. Bella, Asian J. Org.
Chem. 2014, 3, 340–351; h) S. Quintero-Duque, K. M.
Dyballa, I. Fleischer, Tetrahedron Lett. 2015, 56, 2634–
2
2
4
4
È [20]
In conclusion, we have disclosed an iodine-cata-
lyzed direct transformation of terminal alkynes to pri-
mary amides via a CꢀC bond cleavage reaction under
oxidative conditions at room temperature. This up-
dates the literature concerning the transformation of
primary alkynes to other useful products. The reaction
proceeds via initial hydroamination of the acetylenic
bond followed by liberation of one carbon as CH2I2
which becomes the source of iodine under the visible
light. This CꢀC bond cleavage strategy is attractive
2650; i) P. Gao, X.-R. Song, X.-Y. Liu, Y.-M. Liang,
Chem. Eur. J. 2015, 21, 7648–7661; j) T. Besset, T. Pois-
son, X. Pannecoucke, Eur. J. Org. Chem. 2015, 2765–
not only because of the use of an inexpensive catalyst
and metal-free mild reaction conditions but also be-
cause it employs readily available starting materials
which can be used without preliminary functionaliza-
tion.
2
2
2
789; k) S. Hassan, T. J. J. Mueller, Adv. Synth. Catal.
015, 357, 617–666; l) G. Fang, X. Bi, Chem. Soc. Rev.
015, 44, 8124–8173.
[
[
2] a) Modern Acetylene Chemistry, (Eds.: P. J. Stang, F.
Diederich), VCH, Weinheim, 1995; b) Acetylene
Chemistry, (Eds.: F. Diederich, P. J. Stang, R. R. Tyk-
winski), Wiley-VCH, Weinheim, 2005.
3] For reviews on CÀC cleavage, see: a) H. Yorimitsu, K.
Experimental Section
Oshima, Bull. Chem. Soc. Jpn. 2009, 82, 778–792; b) M.
Murakami, T. Matsuda, Chem. Commun. 2011, 47,
General Procedure for the Transformation of 1 to 2
as Exemplified for 2b
1100–1105; c) C. Aïssa, Synthesis 2011, 3389–3407;
d) K. Ruhland, Eur. J. Org. Chem. 2012, 2683–2706;
e) C. J. Allpress, L. M. Berreau, Coord. Chem. Rev.
2013, 257, 3005–3029; f) F. Chen, T. Wang, N. Jiao,
Chem. Rev. 2014, 114, 8613–8661; g) H. Liu, M. Feng,
X. Jiang, Chem. Asian J. 2014, 9, 3360–3389; h) I.
Marek, A. Masarwa, P. -O. Delaye, M. Leibeling,
Angew. Chem. 2015, 127, 424–439; Angew. Chem. Int.
Ed. 2015, 54, 414–429.
To a stirred solution of 1-(tert-butyl)-4-ethynylbenzene 1b
(
0.2 g, 1.26 mmol) in DMSO (5 mL) was added molecular
iodine (0.097 g, 0.38 mmol), aqueous NH3 (25%) (107 mL,
.3 mmol) and H O (35%) (86 mL, 2.52 mmol) were then
6
2
2
added to the reaction mixture at room temperature and the
reaction was allowed to continue for 3 h under visible light
(150 W tungsten filament lamp) Thereafter the reaction was
quenched by the addition of Na S O (10% w/w aqueous,
[4] a) H. Adams, L. V. Y. Guio, M. J. Morris, S. E. Spey, J.
Chem. Soc. Dalton Trans. 2002, 2907–2915; b) R. L. M.
Chamberlin, D. C. Rosenfeld, P. T. Wolczanski, E. B.
Lobkovsky, Organometallics 2002, 21, 2724–2735; c) N.
Hayashi, D. M. Ho, R. A. Pascal Jr, Tetrahedron Lett.
2000, 41, 4261–4376; d) G. A. Cairns, N. Carr, M.
Green, M. F. Mahon, Chem. Commun. 1996, 2431–
2432; e) J. M. OꢁConnor, L. Pu, J. Am. Chem. Soc.
1990, 112, 9013–9015; f) R. M. Moriarty, R. Penmasta,
A. K. Awasthi, I. Prakash, J. Org. Chem. 1988, 53,
6124–6125; g) Y. Sawaki, H. Inoue, Y. Ogata, Bull.
Chem. Soc. Jpn. 1983, 56, 1133–1136; h) B. P. Sullivan,
R. S. Smythe, E. M. Kober, T. J. Meyer, J. Am. Chem.
Soc. 1982, 104, 4701–4703.
2
2
3
1
(
0 mL) and the resulting mixture was extracted with EtOAc
320 mL). The combined organic fractions were dried over
Na SO , and the solvent was removed under vacuum. The
2
4
crude product thus obtained was purified by chromatogra-
phy over a column of silica gel using hexanes/EtOAc
(
6.0:4.0, v/v) as eluent to afford the desired product 4-tert-
[21]
butylbenzamide
(2b) as a white solid; yield: 0.205 g
(
92%); mp 170–1728C [lit. 168–1708C]; R =0.42 (hexane:
f
1
EtOAc, 6:4, v/v); H NMR (400 MHz, CDCl ): d=1.34 (s,
3
9
8
1
H), 6.14 (bs, 2H), 7.45 (d, J=8.5 Hz, 2H), 7.75 (d, J=
13
.5 Hz, 2H); C NMR (100 MHz, CDCl ): d=31.3, 35.1,
3
+
25.7, 127.4, 130.6, 155.6, 169.7; MS (ESI ): m/z=178.2.
[
5] For metal-based approaches to CꢀC cleavage, see:
a) C.-H. Jun, H. Lee, C.-W. Moon, H.-S. Hong, J. Am.
Chem. Soc. 2001, 123, 8600–8601; b) T. Shimada, Y. Ya-
mamoto, J. Am. Chem. Soc. 2003, 125, 6646–6647; c) S.
Datta, C.-L. Chang, K.-L. Yeh, R.-S. Liu, J. Am. Chem.
Soc. 2003, 125, 9294–9295; d) D. Yang, F. Chen, Z.-M.
Acknowledgements
One of the authors (SUD) gratefully acknowledges the finan-
cial assistance in the form of senior research fellowship from
5
04
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 2016, 358, 500 – 505