D
A. S. Barrow, J. E. Moses
Letter
Synlett
salt (Scheme 4).21 The fluoride ion could subsequently acti-
vate the TMSN3 toward nucleophilic attack, yielding the de-
sired sulfonyl azide and regenerating the tertiary amine.
(6) Culhane, J. C.; Fokin, V. V. Org. Lett. 2011, 13, 4578.
(7) (a) Aswad, M.; Chiba, J.; Tomohiro, T.; Hatanaka, Y. Chem.
Commun. 2013, 10242. (b) Bae, I.; Han, H.; Chang, S. J. Am. Chem.
Soc. 2005, 127, 2038. (c) Fleury, L. M.; Wilson, E. E.; Vogt, M.;
Fan, T. J.; Oliver, A. G.; Ashfeld, B. L. Angew. Chem. Int. Ed. 2013,
52, 11589.
RSO2F
(8) (a) Cassidy, M. P.; Raushel, J.; Fokin, V. V. Angew. Chem. Int. Ed.
2006, 45, 3154. (b) Shangguan, N.; Katukojvala, S.; Greenberg,
R.; Williams, L. J. J. Am. Chem. Soc. 2003, 125, 7754. (c) Wu, X.;
Hu, L. J. Org. Chem. 2007, 72, 765.
R''
N+
R'
R'''
R''
N
F-
R'
R'''
(9) Driver, T. G. Org. Biomol. Chem. 2010, 8, 3831.
SO2R
(10) Katritzky, A. R.; Widyan, K.; Gyanda, K. Synthesis 2008, 1201.
(11) Maleki, B.; Hemmati, S.; Tayebee, R.; Salemi, S.; Farokhzad, Y.;
Baghayeri, M.; Zonoz, F. M.; Akbarzadeh, E.; Moradi, R.;
Entezari, A.; Abdi, M. R.; Ashrafi, S. S.; Taimazi, F.; Hashemi, M.
Helv. Chim. Acta 2013, 96, 2147.
TMSN3
RSO2N3 + TMSF
(12) Štefane, B.; Kočevar, M.; Polanc, S. J. Org. Chem. 1997, 62, 7165.
(13) Raushel, J.; Pitram, S. M.; Fokin, V. V. Org. Lett. 2008, 10, 3385.
(14) Goddard-Borger, E. D.; Stick, R. V. Org. Lett. 2007, 9, 3797.
(15) Stevens, M. Y.; Sawant, R. T.; Odell, L. R. J. Org. Chem. 2014, 79,
4826.
(16) Goddard-Borger, E. D.; Stick, R. V. Org. Lett. 2011, 13, 2514.
(17) Suárez, J. R.; Trastoy, B.; Pérez-Ojeda, M. E.; Marín-Barrios, R.;
Chiara, J. L. Adv. Synth. Catal. 2010, 352, 2515.
Scheme 4 Proposed mechanistic route
This reactivity pattern is consistent with the previously
reported observation that organic bases activate both sulfo-
nyl fluorides and silyl groups in transformations such as the
conversion of hydroxyl groups into fluorides and silyl ether
hydrolysis.29,30
(18) Davies, H. M. L.; Cantrell, W. R.; Romines, K. R.; Baum, J. S. Org.
Synth. 1992, 70, 93.
In summary, we have developed an operationally simple
procedure for the formation of sulfonyl azides, from the ro-
bust sulfonyl fluoride via base activation, with consistently
high yields obtained with a range of functional groups. This
methodology offers a complimentary approach for when
sulfonyl chlorides are inappropriate precursors. Additional-
ly, conditions have been developed that allow the synthesis
of sulfonyl azides from base-sensitive sulfonyl fluoride pre-
cursors. The sulfonyl azides formed can be used in situ as
diazo-transfer reagents, reacting with both diones and pri-
mary amines to give the corresponding diazo and azide
products in moderate to excellent yields (50–90%).
(19) Dong, J.; Krasnova, L.; Finn, M. G.; Sharpless, K. B. Angew. Chem.
Int. Ed. 2014, 53, 9430.
(20) It should be noted that, in general, sulfonyl chlorides do not
undergo reductive collapse in the presence of azide ions.
(21) Gembus, V.; Marsais, F.; Levacher, V. Synlett 2008, 1463.
(22) There is literature precedent for the conversion of sulfonyl fluo-
rides to sulfonyl azides using NaN3 in MeCN on an extremely
electrophilic substrate: (a) Kamoshenkova, O. M.; Boiko, V. N. J.
Fluorine Chem. 2010, 131, 248. Conversion of sulfonyl fluorides
to sulfonyl azides using NaN3 in wet acetone has been reported:
(b) McManus, S. P.; Smith, M. R.; Abramovitch, R. A.; Offor, M. N.
J. Org. Chem. 1984, 49, 683.
(23) We continued our studies with TMSN3 over NaN3 due to its con-
venient liquid form, although both are viable options.
(24) Typical Procedure for the Synthesis of Compound 2a
To a solution of 2-nitrobenzenesulfonyl fluoride (103 mg, 0.5
mmol) in MeCN (1 mL) was added DBU (22 μL, 0.15 mmol, 0.3
equiv) followed by TMSN3 (50 μL, 0.375 mmol, 0.75 equiv). The
resultant solution was stirred at room temperature for 15 min,
then a further portion of TMSN3 (50 μL, 0.375 mmol, 0.75 equiv)
was added. The solution was stirred for a further 45 min, fil-
tered through a silica plug, eluting with EtOAc (50 mL), and vol-
atiles removed under reduced pressure to yield 2a as a white
solid. (105 mg, 0.46 mmol, 92%). 1H NMR (400 MHz, CDCl3): δ =
8.49–8.46 (m, 2 H), 8.20–8.16 (m, 2 H). 13C NMR (101 MHz,
Acknowledgment
We thank the University of Nottingham for studentship support
(ASB).
Supporting Information
Supporting information for this article is available online at
S
u
p
p
ortioInfgrmoaitn
S
u
p
p
ortiInfogrmoaitn
CDCl3): δ = 151.2, 143.7, 128.9, 124.9. IR (CHCl3): 2134 cm–1
.
(25) See the Supporting Information for more information.
References and Notes
(26) Whilst the reduction of the corresponding sulfonyl chloride has
been reported, in our hands, the transformation proved unsuc-
cessful: Basoglu, S.; Demirbas, A.; Ulker, S.; Alpay-Karaoglu, S.;
Demirbas, N. Eur. J. Med. Chem. 2013, 69, 622.
(27) Barral, K.; Moorhouse, A. D.; Moses, J. E. Org. Lett. 2007, 9, 1809.
(28) Excess TMSN3 is destroyed in the workup procedure with tri-
phenylphosphine in the rotary evaporator solvent trap.
(29) Vorbrüggen, H. Synthesis 2008, 1165.
(1) Kim, S. H.; Park, S. H.; Choi, J. H.; Chang, S. Chem. Asian J. 2011, 6,
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(2) Ye, T.; Mckervey, M. A. Chem. Rev. 1994, 1091.
(3) Hughes, C. C.; Kennedy-Smith, J. J.; Trauner, D. Org. Lett. 2003, 5,
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(4) Kitamura, M.; Kato, S.; Yano, M.; Tashiro, N.; Shiratake, Y.;
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(5) Erdik, E. Tetrahedron 2004, 60, 8747.
(30) Yeom, C.-E.; Kim, H.; Lee, S.; Kim, B. Synlett 2007, 146.
© Georg Thieme Verlag Stuttgart · New York — Synlett 2016, 27, A–D