I. Nicolas et al. / Tetrahedron Letters 50 (2009) 5149–5151
5151
H
N2
O
Catalyst (1, 2, 3)
N
PhNH2
N2
+
+
COPh
R1= H, CH3
R1
Ph
Ph
CH2Cl2
R1
Scheme 2. N–H insertion into aniline by diazoketones.
6. Nakamura, A.; Konishi, A.; Tatsuno, Y.; Otsuka, S. J. Am. Chem. Soc. 1978, 100,
3443–3448.
Table 3
NH Insertion of aniline with N2CHCOC6H5 and N2C(CH3)COC6H5 catalyzed by Fe TPP
(Cl) (1), Fe Halt (Cl)(2), and Fe TPP triflate (3)a
7. Nicolas, I.; Le Maux, P.; Simonneaux, G. Tetrahedron Lett. 2008, 49, 2111–2113.
8. Doyle, M. P.; Eismont, M. Y.; Zhou, Q. L. Russ. Chem. Bull. 1997, 46, 955–958.
9. Müller, P.; Maîtrejean, E. Collect. Czech. Chem. Commun. 1999, 64, 1807–1826.
10. Gross, Z.; Galili, N.; Simkhovich, L. Tetrahedron Lett. 1999, 40, 1571–1574.
11. Hamaker, C. G.; Mirafzal, G. A.; Woo, L. K. Organometallics 2001, 20, 5171–5176.
12. Le Maux, P.; Juillard, S.; Simonneaux, G. Synthesis 2006, 10, 1701–1704.
13. Lai, T. S.; Chan, F. Y.; So, P. K.; Ma, D. L.; Wong, K. Y.; Che, C. M. Dalton Trans.
2006, 4845–4851.
14. Halterman, R. L.; Jan, S. T. J. Org. Chem. 1991, 56, 5253–5254.
15. Johnson, C. R.; Schroeck, C. W. J. Am. Chem. Soc. 1968, 90, 6852–6854.
16. Liu, B.; Zhu, S. F.; Zhang, W.; Chen, C.; Zhou, Q. L. J. Am. Chem. Soc. 2007, 129,
5834–5835.
Entry
Catalyst
Diazo
T (°C)
Time (h)
Yieldb (%)
1
2
3
4
5
1
1
2
3
3
N2CHCOC6H5
20
40
40
20
20
0.25
2
2
0.25
2
90
66
51c
92
20
N2C(CH3)COC6H5
N2C(CH3)COC6H5
N2CHCOC6H5
N2C(CH3)COC6H5
a
A molar ratio of 1:200:200 for catalyst: diazo: aniline was employed.
b
Yields were determined by isolation of product by column chromatography on
silica gel.
17. Aviv, I.; Gross, Z. Chem. Eur. J. 2008, 14, 3995–4005.
18. A solution of diazoacetophenone (29.2 mg, 0.2 mmol) in 0.2 ml chloroform was
c
ee of the insertion product was controlled by chiral HPLC using a Chiralcel OJ
column, ee = 0.
added dropwise to a 0.8 ml chloroform solution of Fe TPP (Cl) 1 (0.7 mg,
1 lmol), pyridine (0.16 mg, 2 lmol), and styrene (104 mg, 1 mmol) under a
nitrogen atmosphere. The reaction mixture was stirred until complete
transformation of the diazo compound (the reaction was monitored by TLC).
The solvent was then removed under reduced pressure and the residue was
purified by column chromatography on silica gel (pentane:CH2Cl2 = 1:1) to
give a mixture of cis and trans-2-phenyl-1-benzoyl cyclopropane (14 mg, 32%
yield). The diastereoselectivity was determined by GC analysis, 91:9, using a
CP-Chirasil-Dex column. The dimer product was then recovered after elution
with a pentane: CH2Cl2 mixture (1:2) (10 mg, 42% yield).
Finally, we investigated possible asymmetric N–H insertion into
aniline (Scheme 2) catalyzed by chiral iron porphyrin since a suc-
cessful example was reported by Zhou with copper complexes of
chiral spiro ligands, very recently.16 The results are summarized
in Table 3. With diazoacetophenone, the catalytic reaction was
very effective at room temperature, (90–92% yield) to give N–H
insertion, both with complex 1 or complex 3 (entry 1 or 4, Table
19. X-ray crystallographic study: (C16H13Br1O1); M = 301.17. APEXII, Bruker-AXS
diffractometer, Mo-K
P 21 21 21, a = 5.1692(9), b = 7.9218(12), c = 32.549(5) Å, V = 1332.9(4) Å3,
Z = 4, d = 1.501 g cmÀ3 = 3.068 mmÀ1. The structure was solved by direct
methods using the SIR97 program [a], and then refined with full-matrix least-
square methods based on F2
SHELX-97) [b] with the aid of the WINGX [c] program.
a radiation (k = 0.71073 Å), T = 100(2) K; orthorhombic
3). Using
a-methyl acetophenone, chosen to get a possible asym-
,
l
metric induction, N–H insertion was also possible but with lower
yield (51%). Unfortunately, no chiral induction was detected using
iron chiral porphyrin as the catalyst (entry 3). A similar situation
was previously observed with ethyl diazoacetate insertion into
N–H bond catalyzed by heme derivatives.17
(
All non-hydrogen atoms were refined with anisotropic thermal parameters. H
atoms were finally included in their calculated positions. A final refinement on
F2 with 3024 unique intensities and 163 parameters converged at
x
R(F2) = 0.0479 (R(F) = 0.0292) for 2611 observed reflections with I > 2
r(I).
(a) Altomare, A., Burla, M. C.; Camalli, M.; Cascarano, G.; Giacovazzo, C.;
Guagliardi, A.; Moliterni, A. G. G.; Polidori, G.; Spagna, R. J. Appl. Crystallogr.
1999, 32, 115–119. (b) SHELX97—Programs for Crystal Structure Analysis
(Release 97-2). G. M. Sheldrick, Institüt für Anorganische Chemie der
Universität, Tammanstrasse 4, D-3400 Göttingen, Germany, 1998. (c)
Farrugia, L. J. J. Appl. Cryst. 1999, 32, 837–838.
In conclusion, chiral iron porphyrins are good catalysts for
asymmetric cyclopropanation of styrene18 yielding optically active
cyclopropyl ketones19 and for N–H insertion of aniline20 but with-
out any asymmetric induction in the latter case.
20. Fe TTP (Cl) 1 (0.7 mg, 1 lmol), diazoacetophenone (29.2 mg, 0.2 mmol), and
References and notes
aniline (18.6 mg, 0.2 mmol) were stirred in a solution of CH2Cl2 (1 ml) at room
temperature under a nitrogen atmosphere until complete consumption of
diazo was evident by TLC (10 min). The solvent was then removed under
reduced pressure and the residue was purified by column chromatography on
silica gel (pentane: ether = 19:1) to give the insertion product (38 mg, 90%
yield). 1H NMR (CDCl3, 200 MHz) d 1.53 (d, J = 6.8 Hz,3H), 4.76 (s, 1H), 5.18 (q,
J = 6.6 Hz, 1H), 6.72 (d, J = 8.2 Hz, 2H), 6.76 (t, J = 8.0 Hz, 1H), 7.23 (t, J = 7.8 Hz,
2H), 7.52–7.66 (m, 3H), 8.06 (d, J = 8.0 Hz, 2H).
1. (a) Doyle, M. P. Angew. Chem., Int. Ed. 2009, 48, 850–852; (b) Lebel, H.; Marcoux,
J. F.; Molinaro, C.; Charette, A. B. Chem. Rev. 2003, 103, 977–1050.
2. Ye, T.; McKervey, M. A. Chem. Rev. 1994, 94, 1091–1160.
3. Pfaltz, A. Acc. Chem. Res. 1993, 26, 339–345.
4. Piqué, C.; Fähndrich, B.; Pfaltz, A. Synlett 1995, 491–492.
5. Saha, B.; Uchida, T.; Katsuki, T. Chem. Lett. 2002, 846–847.