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COMMUNICATION
ChemComm
DOI: 10.1039/C6CC01576J
BnNH2 was used as nitrogen source. Aromatic amine, PhNH2,
could furnish the desired pyrroles 6b and 6c in excellent yields
when reacted with fluoroacetyl cyclopropanes 3a and 3a’.
Commission (Peak Discipline Construction Program) for their
financial support.
Notes and references
a School of Environmental and Chemical Engineering, Shanghai University,
99 Shang Da Road, Shanghai 200444, P. R. China. E-mail:
wgcao@staff.shu.edu.cn, Fax: +86-21-6613 4856
b
Department of Chemistry, Innovative Drug Research Center, Shanghai
University, 99 Shang Da Road, Shanghai 200444, P. R. China
Key Laboratory of Organofluorine Chemistry, Shanghai Institute of
c
Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road,
Shanghai 200032, P. R. China
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of
d
Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road,
Shanghai 200032, P. R. China
Key Laboratory of Synthetic Organic Chemistry of Natural Substances,
e
Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences,
345 Lingling Road, Shanghai 200032, P. R. China
Scheme 9. Further Transformations of Cyclopropanes
† Electronic supplementary information (ESI) available: Experimental
procedure, spectral data, and copies of the NMR spectra of products. See
DOI: 10.1039/c0ccxxxxxx
A
tentative reaction mechanism for this iodine-promoted
cyclopropanation reaction was then proposed in Scheme 10.
Initially fluoroacetyl acetate was converted into 2-iodo-
fluoroacetyl acetate A under the conditions of I2/oxidant. In the
presence of base, 2-iodo-fluoroacetyl acetate A underwent
1
(1). (a) R. A. Moss; M. P. Doyle, Contemporary Carbene Chemistry,
Wiley, New Jeesey, 2014; (b) M. P. Doyle; M. A. McKervey; T. Ye,
Modern Catalytic Methods for Organic Synthesis with Diazo
Compounds, Wiley, New York, 1997.
(2). (a) W. Kirmse, Carbene Chemistry, Academic Press, Newyork and
London, 1971. (b) E. Abele; R. Abele; E. Lukevics, Heterocycl.
Commun. 1998, 4, 253. (c) W. Kirmse; W. von E. Doering,
Tetrahedron 1960, 11, 266. (d) E. V. Dehmlow, Tetrahedron Lett.
1976, 91. (e) M. Rabinovitz; Y. Sasson; M. Halpern, J. Org. Chem.
1983, 48, 1022. (f). E. J. Fendler; J. H. Fendler, Adv. Phys. Org.
Chem. 1970, 8, 271. (g) J. P. Jayachandran; M.-L. Wang, Synth.
Commun. 1999, 29, 4101.
α-
elimination to lead free carbene intermediate C, which then was
cyclopropanated with aromatic alkenes to lead the corresponding
cyclopropane 3. The control reactions indicated that iodide ion (I-)
could promote the transformation of cyclopropane
dihydrofuran 4.
3 into
(3). M. S. Singh, Reactive Intermediates in Organic Chemistry, Wiley,
Weinheim, 2014, pp 153-196.
(4). (a) H. Lebel; J.-F. Marcoux; C. Molinaro; A. B. Charette, Chem. Rev.
2003, 103, 977. (b) H. M. L. Davies; E. Antoulinakis, Org. React.
2001, 57, 1-326. (c) M. P. Doyle; D. C. Forbes, Chem. Rev. 1998, 98,
911. (d) A. Padwa; K. E. Krumpe, Tetrahedron 1992, 48, 5385. (e)
M. P. Doyle, Chem. Rev. 1986, 86, 919. (f) H. M. L. Davies; R. E. J.
Beckwith, Chem. Rev. 2003, 103, 2861.
(5). (a) B. E. Smart, J. Fluorine Chem. 2001, 109, 3. (b) F. M. D. Ismail,
J. Fluorine Chem. 2002, 118, 27. (c) K. Müller, C. Faeh, F.
Diederich, Science 2007, 317, 1881.
(6). (a) J. Pietruszka, Chem. Rev. 2003, 103, 1051. (b) L. A. Wessjohann;
W. Brandt; T. Thiemann, Chem. Rev. 2003, 103, 1625. (c) W. A.
Donaldson, Tetrahedron 2001, 57, 8589. (d) J. Salaun, Chem. Rev.
1989, 89, 1247.
(7). (a) J. Barluenga; M. Marco-Arias; F. González-Bobes; A. Ballesteros;
J. M. González, Chem. Commun. 2004, 2616. (b) C.-K. Sha; J.-J.
Young; T.-S. Jean, J. Org. Chem. 1987, 52, 3920. (c) H. Cao; J.
Yuan; C. Liu; X. Hu; A. Lei, RSC Adv. 2015, 5, 41493. (d) J.
Barluenga; E. Campos-Gomez; D. Rodriguez; F. Gonzalez-Bobes; J.
M. Gonzalez, Angew. Chem. Int. Ed. 2005, 44, 5851. (e) V. Estevez;
M. Villacampa; J. C. Menendez, Chem. Commun. 2013, 49, 591.
(8). [3+2] Cycloaddition is another representative reaction of carbene.
For example: L. Xia; Y. R. Lee, Adv. Synth. Cat. 2013, 355, 2361.
(9). P. Gopinath; S. Chandrasekaran, J. Org. Chem. 2011, 76, 700.
(10). (a) R. A. Jones; G. P. Bean, The Chemistry of Pyrroles; Academic:
London, 1977; pp 1-5. (b) D. L. Boger; C. W. Boyce; M. A. Labrili;
C. A. Sehon; Q. Jin, J. Am. Chem. Soc. 1999, 121, 54. (c) J. Lehuede;
B. Fauconneau; L. Barrier; M. Ourakow; A. Piriou; J. M. Vierfond,
Eur. J. Med. Chem. 1999, 34, 991. (d) X. Feng; Q. Wang; W. Lin;
G.-L. Dou; Z.-B. Huang; D.-Q. Shi, Org. Lett. 2013, 15, 2542.
Scheme 10. Proposed Reaction Mechanism.
In conclusion, we have developed a mild iodine-catalyzed and
transition metal-free method to generate acceptor/ acceptor-carbene
via base-promoted
α-elimination of 2-iodo-fluoroacetyl acetate,
which was generated in situ from fluoroacetyl acetate 1 with
I2/oxidant. The control reactions revealed that iodide ion could
promote the transformation of cyclopropane 3 into fluoromethyl
dihydrofuran 4 efficiently. Furthermore, the product fluoroacetyl
cyclopropane 3 could be further converted into fluoromethyl
pyrrole 6 through the ring-expansion with amine and followed by
oxidation with DDQ. We believed such process would provide
some useful insights for the carbene chemistry. Furthermore, owing
to the excellent substrate scopes and mild reaction conditions, this
transition metal-free system may hold considerable potential for the
construction of useful heterocylic molecules. Investigations on the
detailed reaction mechanism, and additional applications of this
reaction are underway in our laboratory.
We are grateful to the National Natural Science Foundation of
China (Grant Nos. 21542005, 21272152), Yang Fan Program of
Science and Technology Commission of Shanghai Municipality
(Grant No. 15YF1404200) and Shanghai Municipal Education
4 | J. Name., 2012, 00, 1-3
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