Rhodium(II) acetate catalyzed synthesis of cyclic enamides and enamines via β-hydride elimination

Article abstract of DOI:10.1055/s-2002-20951

A series of cylic diazoamides and diazoamines were synthesized. Treatment of these cylic diazoamides and diazoamines with a catalytic amount of rhodium(II) acetate furnished the corresponding cyclic enamides and enamines, respectively. Interestingly, cyclic diazoamines produced stereoselectively Z-enamines.

Full text of DOI:10.1055/s-2002-20951

PAPER
471
Rhodium(II) Acetate Catalyzed Synthesis of Cyclic Enamides and Enamines
via -Hydride Elimination
Synthesis of
C
e
yclic Enam
n
ides andEna
g
mines odagounder Muthusamy,* Chidambaram Gunanathan, Srinivasarao Arulananda Babu
Silicates and Catalysis Discipline, Central Salt and Marine Chemicals Research Institute, Bhavnagar 364 002, India
Fax +91(278)567562; E-mail: salt@csir.res.in
Received 24 October 2001; revised 21 January 2002
smoothly only to the ester functional group and provid-
ed compounds 3. Without the isolation of formyl com-
pounds 3, the diazo transfer reaction was performed using
Abstract: A series of cylic diazoamides and diazoamines were syn-
thesized. Treatment of these cylic diazoamides and diazoamines
with a catalytic amount of rhodium(II) acetate furnished the corre-
sponding cyclic enamides and enamines, respectively. Interesting- mesyl azide to afford the cyclic diazoamides 4a–c in good
ly, cyclic diazoamines produced stereoselectively Z-enamines. yields (Scheme 1).
Key words: diazoamides, diazoamines, enamides, enamines, rhod- We initially investigated the performance of diazoamide
ium(II) acetate
4
a using rhodium( ) acetate as a catalyst in the absence
of any dipolarophile. Diazoamide 4a was dissolved in an-
hydrous benzene and refluxed with 0.3 mol% of rhodi-
The utility of -diazo carbonyl compounds in modern or- um(II) acetate for 25 h. The reaction was followed by
ganic synthesis and their participation in a variety of TLC until the disappearance of diazoamide 4a. The chro-
transformations like cyclopropanation, insertion reaction matographic purification of the crude reaction mixture af-
1
and ylide formation is well documented. The tandem pro- forded two products which were characterized as cyclic
cesses involving rhodium carbenoids generated from dia- enamides of type 5a (40%) and 6a (31%) with Z and E ge-
zo carbonyl compounds with a catalytic amount of ometry, respectively (Scheme 1, Table).
rhodium(II) acetate have been used to construct various
2
complex polycyclic systems. The rhodium(II)-catalyzed
Y
Y
Y
( )n
(
)n
Ethyl acrylate
( )n
NaH
reactions of cyclic and acyclic diazo ketoamides were
skillfully applied to generate ylides followed by trapping
with dipolarophiles to synthesize various alkaloids and
nitrogen containing heterocycles. The study of -hy-
dride elimination reactions of rhodium carbenoid is
scarcely reported in the literature, particularly to obtain
cis-enoates, trans- -methoxy enones and , -unsaturat-
ed esters. However, to the best of our knowledge there is
no report dealing with the -hydride elimination chemis-
try of diazoamides and diazoamines. In continuation of
our interest on the reactions of diazo carbonyl
compounds and to expose the novel utilities of these dia-
zo compounds, we herein wish to report the results of -
hydride elimination reactions of cyclic diazoamides and
diazoamines in the presence of rhodium(II) acetate as a
catalyst.
N
H
X
NaOH powder
THF
N
X
HCOOEt
benzene
N
X
CHO
3
1
COOEt
COOEt
2
,4
2
3
MsN3
5
6
Y
Y
Y
(
)n
( )n
( )n
7
Rh2(OAc)4
+
N
X
N
X
N
X
N2
dry benzene
COOEt
1
COOEt
COOEt
6
5
4
8
Scheme 1
IR spectrum of compound 5a showed a band at 1632
–
1
cm indicating the presence of a olefin functional group.
1
The H NMR spectrum of 5a displayed characteristic two
doublets at = 5.14 and 7.10 with a coupling constant of
J = 10.6 Hz confirming the Z geometry. The C NMR and
DEPT-135 spectra of 5a disclosed the presence of one
For this purpose, -diazo carbonyl compounds 4a–f hav-
ing -hydrogen atoms were chosen for this study. The re-
quired cyclic diazoamides 4a–c can be easily prepared
from the corresponding cyclic amides 1a–c as described
below. The Michael addition reaction of cyclic amides
a–c and ethyl acrylate afforded the corresponding cyclic
I3
CH , four CH , two CH and two quaternary carbons,
9
3
2
which clearly confirmed the structure of compound 5a as
an Z enamide.
1
amides 2a–c in quantitative yields. To generate a diazo
10
IR spectrum of compound 6a had absorption band at 1629
group adjacent to ester functionality, the formylation re-
action of cyclic amides 2a–c using sodium hydride/ethyl
formate was carried out. The formylation took place
–
1
1
cm for the presence of olefin moiety. The H NMR spec-
trum of 6a showed two characteristic doublets at =5.21
and 8.09 with a coupling constant of J = 14.2 Hz indicat-
I3
ing the E geometry. The C NMR and DEPT-135 spectra
Synthesis 2002, No. 4, 15 03 2002. Article Identifier:
of 6a revealed the presence of one CH , four CH , two CH
and two quaternary carbons, which confirmed the struc-
ture of compound 6a as an E enamide.
3 2
1
437-210X,E;2002,0,04,0471,0474,ftx,en;E07301SS.pdf.
Georg Thieme Verlag Stuttgart · New York
ISSN 0039-7881
©

4
72
S. Muthusamy et al.
PAPER
Table Rh(OAc) Catalyzed Reaction of Diazoamides and Diazoamines
2
Entry
X
Y
n
Yield of 4 (%)a
Yield of 5 and 6 (%)
% of Z/E-Isomers
5
6
43
a
b
c
O
CH2
CH2
CH2
CH2
CH2
O
0
1
2
0
1
1
95
98
97
60
65
68
71
76
65
45
47
48
57
30
O
70
60
0
O
40
d
e
H2
H2
H2
100
100
100
0
f
0
a
Yields refer to isolated pure diazo compounds 4 from 2.
Diazoamides 4b,c were also studied under similar reac-
tion conditions to afford the corresponding cyclic ena-
mides 5/6b and 5/6c in good yields, respectively. The
rhodium(II) acetate catalyzed reaction of 4c was followed
by IR until the disappearance of the characteristic diazo
Y
EtO2C
N
EtO C
2
Ha
N
X
Rh(II)
4a-f
Ha
Hb
–
1
X
peak at 2108 cm since the R values of 4c and 6c in TLC
f
Hb
LnRh
LnRh
are identical.
After studying various cyclic diazoamides, we extended
the study to the rhodium(II)-catalyzed behavior of cyclic
diazoamines 4d–f. Thus, we synthesized the diazoamines
Y
7
a
7b
X=H or O
X=O
2
4
d–f from the corresponding cyclic amines 1d–f by fol-
lowing the similar procedure described for compounds
a–c. Subsequently, the rhodium(II) catalyzed reaction of
compound 4d was carried out followed by alumina col-
5
6
Scheme 2
4
umn chromatographic purification of the residue to afford The -hydride elimination is generally considered as a rel-
only one product 5d in moderate yield. Based on its inter- atively low-energy pathway for metal carbene decompo-
1
2
related spectral data, compound 5d was characterized as sition reactions. But the literature precedents show that
an Z-enamine. Surprisingly this reaction afforded stereo- this elimination is competitive with the other reaction
1
3
14
selectively Z-isomer 5d and no E-isomer could be ob- pathways like C–H insertion,
O–H insertion,
6
,13b
5
served. The similar reaction was carried out with intramolecular cyclopropanation,
dimerization and
diazoamines 4e,f which also afforded exclusively the cor- Wolff rearrangement.15 We could not observe any other
responding enamines 5e,f with Z geometry. The forma- product produced by possible competition reactions like
tion of products 5 and 6 may be explained by a -hydride C–H insertion or ylide formation in the above substrates 4.
1
1
elimination of diazo compounds 4a–f in the presence of
In conclusion, we have studied the -hydride elimination
rhodium(II) acetate catalyst. Interestingly, a complete ste-
reactions of cyclic diazoamides which afforded both Z-
reoselectivity was observed in cyclic amines 4d–f but not
and E-enamides without any selectivity in the presence of
in the case of cyclic amides 4a–c. This may be rational-
rhodium( ) acetate as a catalyst, whereas the cyclic di-
ized where the intermediate rhodium carbenoids formed
azoamines stereoselectively produced only the Z-enamine
from cyclic amides 4a–c may exist in two conformations
under the similar experimental conditions.
7
a and 7b (Scheme 2) which lead to a mixture of stereoi-
somers 5 and 6. Interestingly, the rhodium carbenoids
Mps are uncorrected. IR spectra were recorded on a Perkin-Elmer
formed from cyclic amines 4d–f exist only in the
1
13
6
Spectrum GX FT-IR spectrophotometer. H NMR and C NMR
spectra were recorded on a Bruker DPX 200 (200 MHz and 50.3
MHz respectively) spectrometer and referenced to internal standard
conformation 7a (X = H ) to afford product 5 with Z ste-
2
reochemistry. The additional carbonyl group adjacent to
nitrogen atom in compounds 4a–c assists partially to the
presence of conformer 7b, which resulted in the E-isomer
TMS using CDCl as solvent. Carbon types were determined from
3
13
DEPT C NMR experiments. Mass analyses were obtained using
6
.
either a Finnigan MAT 8230 (with an ionizing voltage of 70eV) or
+
Jeol M Station 700 (FD method in absolute CH Cl ) mass spec-
2
2
trometer. Elemental analyses were performed on a Perkin-Elmer
Model 2400 analyzer.
Synthesis 2002, No. 4, 471–474 ISSN 0039-7881 © Thieme Stuttgart · New York

PAPER
Synthesis of Cyclic Enamides and Enamines
473
Ethyl (2Z)-3-(2-Oxopyrrolidin-1-yl)prop-2-enoate (5a) and Eth-
yl (2E)-3-(2-Oxopyrrolidin-1-yl)prop-2-enoate (6a); Reactions
of Diazo Compound 4 with Rhodium(II) Acetate Catalyst; Typ-
ical Procedure
Ethyl (2E)-3-(2-Oxopiperidin-1-yl)prop-2-enoate (6b)
Yield: 139 mg (53%); colorless liquid.
IR (CHCl ): 2949, 1667, 1621 (C=C), 1451, 1411, 1292, 1259,
3
–1
1
167, 1097, 1024 cm .
To a stirred solution of the diazo compound 4a (0.30 g, 1.4 mmol)
in anhyd benzene (15 mL) was added a 0.3 mol% of Rh (OAc) un-
1H NMR: = 1.29 (t, 3 H, J = 7.1 Hz, CH ), 1.83–2.04 (complex, 4
3
2
4
H), 2.53–2.59 (m, 2 H), 3.41–3.47 (m, 2 H), 4.19 (q, 2 H, J = 7.1
der an argon atmosphere. The reaction mixture was refluxed for
5 h by following the reaction with TLC until the disappearance of
Hz, OCH ), 5.27 (d, 1 H, J = 14.6 Hz, CH), 8.60 (d, 1 H, J = 14.6
2
2
Hz, CH).
the diazo compound 4a. Then the solvent was removed under re-
duced pressure and the residue was purified using alumina column
chromatography (EtOAc–hexane, 1:2) to afford the enamides 5a
13C NMR:
= 14.2 (CH ), 20.1 (CH ), 22.2 (CH ), 33.0 (CH ), 45.5
3
2
2
2
(
CH ), 59.0 (CH ), 99.8 (CH), 140.6 (NCH), 167.3 (quat-C, CO Et),
2
2
2
(0.125 g, 40%) and 6a (0.095 g, 31%) as colorless solids.
1
69.2 (quat-C, NCO).
FD-MS: m/z = 197 (M+).
Anal. Calcd for C10
60.84; H, 7.66; N, 7.08.
Ethyl (2Z)-3-(2-Oxopyrrolidin-1-yl)prop-2-enoate (5a)
Yield: 104 mg (40%); colorless solid; mp 35–37 °C (hexanes–
EtOAc).
H
15NO : C, 60.90; H, 7.67; N, 7.10. Found: C,
3
IR (CHCl ): 2922, 1716, 1632 (C=C), 1517, 1458, 1356, 1162,
3
–1
Ethyl (2Z)-3-(2-Oxoazepan-1-yl)prop-2-enoate (5c)
Yield: 69 mg (26%); colorless solid; mp 56–58 °C (hexanes–
EtOAc).
1
042, 805 cm .
1H NMR: = 1.28 (t, 3 H, J = 7.1 Hz, CH ), 2.01–2.17 (m, 2 H),
3
2
.48 (t, 2 H, J = 8.2 Hz, CH ), 3.97 (t, 2 H, J = 7.1 Hz, CH ), 4.14
2 2
IR (KBr): 2935, 1709, 1683, 1627 (C=C), 1384, 1358, 1169, 910,
(
q, 2 H, J = 7.1 Hz, OCH ), 5.14 (d, 1 H, J = 10.6 Hz, CH), 7.10 (d,
2
–1
7
34 cm .
1
H, J = 10.6 Hz, CH).
1H NMR: = 1.28 (t, 3 H, J = 7.1 Hz, CH
), 1.73–1.89 (complex, 6
13C NMR:
3
= 14.1 (CH ), 18.5 (CH ), 30.1 (CH ), 48.5 (CH ), 59.9
3
2
2
2
H), 2.67–2.79 (m, 2 H), 3.81–3.85 (m, 2 H), 4.15 (q, 2 H, J = 7.1
(
CH ), 99.1 (CH), 133.5 (NCH), 165.3 (quat-C, CO Et), 175.8
2
2
Hz, OCH ), 5.21 (d, 1 H, J = 10.4 Hz, CH), 7.24 (d, 1 H, J = 10.4
2
(
quat-C, NCO).
Hz, CH).
+
EIMS: m/z (%) = 183 (M , 34), 154 (25), 138 (100), 110 (98), 82
98), 70 (48), 55 (31), 41 (65).
13C NMR:
CH ) 50.9 (CH ), 60.0 (CH ), 102.4 (CH), 140.1 (NCH), 165.1
= 14.2 (CH ), 23.3 (CH ), 29.2 (CH ), 29.5 (CH ), 37.2
3 2 2 2
(
(
2
2
2
Anal. Calcd for C H NO : C, 59.00; H, 7.15; N, 7.65. Found: C,
9
13
3
(quat-C, CO Et), 176.4 (quat-C, NCO).
2
5
9.08; H, 7.12; N, 7.63.
+
EIMS: m/z (%) = 211 (M , 5), 183 (3), 166 (12), 154 (22), 138
(
100), 109 (18), 96 (13), 82 (17), 79 (24), 55 (19), 41 (25), 29 (28).
Anal. Calcd for C11 : C, 62.54; H, 8.11; N, 6.63. Found: C,
62.57; H, 8.08; N, 6.61.
Ethyl (2E)-3-(2-Oxopyrrolidin-1-yl)prop-2-enoate (6a)
Yield: 80 mg (31%); colorless solid; mp 57–58 °C (hexanes–
EtOAc).
H17NO
3
IR (KBr): 2983, 2901, 1730, 1701, 1629 (C=C), 1462, 1406, 1329,
–1
Ethyl (2E)-3-(2-Oxoazepan-1-yl)prop-2-enoate (6c)
Yield: 103 mg (39%); colorless solid; mp 53–55 °C (hexanes–
EtOAc).
1
219, 915, 732 cm .
1H NMR: = 1.29 (t, 3 H, J = 7.1 Hz, CH ), 2.11–2.26 (m, 2 H),
3
2
.57 (t, 2 H, J = 8.3 Hz, CH ), 3.57 (t, 2 H, J = 7.2 Hz, CH ), 4.20
2 2
IR (CHCl ): 2938, 1709, 1621 (C=C), 1476, 1440, 1365, 1256,
3
(
q, 2 H, J = 7.1 Hz, OCH ), 5.21 (d, 1 H, J = 14.2 Hz, CH), 8.09 (d,
2
–1
1
172, 1052, 968, 911 cm .
1
H, J = 14.2 Hz, CH).
1H NMR: = 1.29 (t, 3 H, J = 7.1 Hz, CH
), 1.73–1.79 (complex, 6
13C NMR:
3
= 14.2 (CH ), 17.3 (CH ), 30.8 (CH ), 44.8 (CH ), 60.0
3
2
2
2
H), 2.68–2.73 (m, 2 H), 3.61–3.66 (m, 2 H), 4.19 (q, 2 H, J = 7.1
(
CH ), 100.6 (CH), 137.1 (NCH), 167.0 (quat-C, CO Et), 174.1
2
2
Hz, OCH ), 5.31 (d, 1 H, J = 14.5 Hz, CH), 8.43 (d, 1 H, J = 14.5
2
(
quat-C, NCO).
Hz, CH).
+
EIMS: m/z (%) = 183 (M , 35), 154 (25), 138 (99), 110 (100), 82
98), 70 (43), 41 (59).
13C NMR:
CH ) 45.2 (CH ), 59.7 (CH ), 98.5 (CH), 140.5 (NCH), 167.5
= 14.1 (CH ), 23.2 (CH ), 26.9 (CH ), 28.8 (CH ), 36.7
3 2 2 2
(
(
2
2
2
Anal. Calcd for C H NO : C, 59.00; H, 7.15; N, 7.65. Found: C,
9
13
3
(quat-C, CO Et), 174.6 (quat-C, NCO).
2
5
9.06; H, 7.13; N, 7.67.
FD-MS: m/z = 211 (M+).
Ethyl (2Z)-3-(2-Oxopiperidin-1-yl)prop-2-enoate (5b)
Anal. Calcd for C11
H17NO : C, 62.54; H, 8.11; N, 6.63. Found: C,
3
Yield: 60 mg (23%); colorless liquid.
62.48; H, 8.14; N, 6.61.
IR (CHCl ): 2956, 1709, 1623(C=C), 1475, 1409, 1262, 1161,
3
–1
Ethyl (2Z)-3-(Pyrrolidin-1-yl)prop-2-enoate (5d)
Yield: 116 mg (45%); colorless liquid.
1
095, 830, 738 cm .
1H NMR: = 1.30 (t, 3 H, J = 7.1 Hz, CH ), 1.79–1.92 (complex, 4
3
IR (CHCl ): 2921, 1718, 1633 (C=C), 1519, 1475, 1365, 1162,
3
H), 2.53–2.60 (m, 2 H), 3.72–3.78 (m, 2 H), 4.17 (q, 2 H, J = 7.1
–
1
1
045, 850 cm .
Hz, OCH ), 5.27 (d, 1 H, J = 10.4 Hz, CH), 7.37 (d, 1 H, J = 10.6
2
1H NMR (200 MHz, CDCl
): = 1.25 (t, 3 H, J = 7.1 Hz, CH ),
3
Hz, CH).
3
13C NMR:
1.68–1.76 (complex, 4 H), 3.16–3.21 (complex, 4 H), 4.15 (q, 2 H,
= 14.5 (CH ), 21.3 (CH ), 21.9 (CH ), 35.2 (CH ), 45.7
3
2
2
2
J = 7.1 Hz, OCH ), 4.62 (d, 1 H, J = 13.1 Hz, CH), 7.36 (d, 1 H,
2
(
CH ), 59.2 (CH ), 100.4 (CH), 135.7 (NCH), 165.6 (quat-C,
2 2
J = 13.1 Hz, CH).
CO Et), 171.4 (quat-C, NCO).
2
13C NMR (50.3 MHz, CDCl
CH ), 60.0 (OCH ), 84.3 (CH), 152.7 (NCH), 170.5 (quat-C,
): = 14.7 (CH ), 25.5 (CH ), 50.1
3 2
FD-MS: m/z = 197 (M+).
3
(
2
2
Anal. Calcd for C H NO : C, 60.90; H, 7.67; N, 7.10. Found: C,
10
15
3
CO Et).
2
6
0.97; H, 7.65; N, 7.13.
FD-MS: m/z = 169 (M+).
Synthesis 2002, No. 4, 471–474 ISSN 0039-7881 © Thieme Stuttgart · New York

4
74
S. Muthusamy et al.
PAPER
Anal. Calcd for C H NO : C, 63.88; H, 8.93; N, 8.28. Found: C,
(2) (a) Padwa, A.; Weingarten, M. D. Chem. Rev. 1996, 96,
223. (b) Padwa, A. Acc. Chem. Res. 1991, 24, 22.
c) Padwa, A. Top. Curr. Chem. 1997, 189, 121.
9
15
2
6
3.84; H, 8.92; N, 8.29.
(
Ethyl (2Z)-3-(Piperidin-1-yl)prop-2-enoate (5e)
Yield: 122 mg (47%); colorless liquid.
(3) (a) Padwa, A.; Harring, S. R.; Semones, M. A. J. Org. Chem.
1998, 63, 44. (b) Padwa, A.; Price, A. T. J. Org. Chem.
1
998, 63, 556. (c) Padwa, A.; Brodney, M. A.; Marino, J. P.
IR (CHCl ): 2944, 1676, 1627 (C=C), 1451, 1371, 1338, 1118,
3
–
1
Jr.; Sheehan, S. M. J. Org. Chem. 1997, 62, 78. (d) Marino,
J. P. Jr.; Osterhout, M. H.; Padwa, A. J. Org. Chem. 1995,
60, 2704.
1
048, 910, 739, 650 cm .
1H NMR: = 1.25 (t, 3 H, J = 7.1 Hz, CH ), 1.54–1.67 (complex, 6
3
H), 3.09–3.25 (complex, 4 H), 4.13 (q, 2 H, J = 7.1 Hz, OCH ), 4.62
2
(4) (a) Jauk, B.; Belaj, F.; Kappe, C. O. J. Chem. Soc., Perkin
Trans. 1 1999, 307. (b) Padwa, A.; Brodney, M. A.; Marino,
J. P. Jr.; Osterhout, M. H.; Price, A. T. J. Org. Chem. 1997,
(
d, 1 H, J = 13.1 Hz, CH), 7.30 (d, 1 H, J = 13.1 Hz, CH).
13C NMR:
= 14.6 (CH ), 24.1 (CH ), 25.4 (CH ), 55.8 (OCH ),
3
2
2
2
62, 67. (c) Padwa, A.; Hertzog, D. L.; Nadler, W. R. J. Org.
8
3.8 (CH), 152.0 (NCH), 170.1 (quat-C, CO Et).
2
Chem. 1994, 59, 7072.
FD-MS: m/z = 183 (M+).
(
5) Hudlicky, T.; Olivo, H. F.; Natchus, M. G.; Umpierrez, E. F.;
Pandolfi, E.; Volonterio, C. J. Org. Chem. 1990, 55, 4767.
Anal. Calcd for C H NO : C, 65.55; H, 9.35; N, 7.64. Found: C,
10
17
2
6
5.49; H, 9.38; N, 7.62.
(6) Ikota, N.; Takamura, N.; Young, S. D.; Ganem, B.
Tetrahedron Lett. 1981, 22, 4163.
Ethyl (2Z)-3-(Morpholin-4-yl)acrylate (5f)
Yield: 125 mg (48%); colorless liquid.
(7) Taber, D. F.; Herr, R. J.; Pack, S. K.; Geremia, J. M. J. Org.
Chem. 1996, 61, 2908.
(
8) (a) Muthusamy, S.; Babu, S. A.; Gunanathan, C.; Suresh, E.;
IR (CHCl ): 2929, 1731, 1682 (C=C), 1613, 1446, 1372, 1261,
3
–1
Dastidar, P.; Jasra, R. V. Tetrahedron 2001, 57, 7009.
1
166, 909, 733 cm .
(
b) Muthusamy, S.; Gunanathan, C.; Babu, S. A.
1H NMR: = 1.26 (t, 3 H, J = 7.1 Hz, CH ), 3.20 (complex, 4 H),
3
Tetrahedron Lett. 2001, 42, 523. (c) Muthusamy, S.; Babu,
S. A.; Gunanathan, C.; Suresh, E.; Dastidar, P. Synlett 2001,
3
.70 (complex, 4 H), 4.13 (q, 2 H, J = 7.1 Hz, OCH ), 4.70 (d, 1 H,
2
J = 13.2 Hz, CH), 7.36 (d, 1 H, J = 13.2 Hz, CH).
13C NMR:
= 14.2 (CH ), 48.6 (CH ), 59.1 (CH ), 66.2 (CH ), 86.3
CH), 151.7 (NCH), 170.3 (quat-C, CO Et).
1407. (d) Muthusamy, S.; Babu, S. A.; Gunanathan, C.;
Jasra. R. V. Synlett 2002, 407. (e) Muthusamy, S.; Babu, S.
A.; Gunanathan, C. Tetrahedron Lett. 2000, 41, 8839.
3
2
2
2
(
2
(
f) Muthusamy, S.; Babu, S. A.; Gunanathan, C.; Suresh, E.;
+
EIMS: m/z (%) = 185 (M , 62), 156 (96), 140 (100), 112 (55), 82
62), 42 (53), 29 (79).
Dastidar, P.; Jasra, R. V. Tetrahedron 2000, 56, 6307.
9) Fang, F. G.; Prato, M.; Kim, G.; Danishefsky, S. J.
Tetrahedron Lett. 1989, 30, 3625.
(
(
Anal. Calcd for C H NO : C, 58.36; H, 8.16; N, 7.56. Found: C,
9
15
3
5
8.41; H, 8.13; N, 7.54.
(10) Padwa, A.; Kulkarni, Y. S.; Zhang, Z. J. J. Org. Chem. 1990,
5, 4144.
11) H NMR spectra showed no trace of the E-isomer in the
crude reaction mixtures of 4d–f even before
chromatography.
12) Doyle, M. P.; McKervey, M. A.; Ye, T. Modern Catalytic
Methods for Organic Synthesis with Diazo Compounds.
From Cyclopropanes to Ylides; Wiley-Interscience: New
York, 1998, 608.
5
1
(
Acknowledgments
This research was supported by Young Scientist Scheme, CSIR,
New Delhi. We thank Dr. P. K. Ghosh, Director and Dr. R. V. Jasra,
Head of the division, for their encouragement shown in this work.
C. G. and S. A. B. thank CSIR, New Delhi for a Fellowship.
(
(
13) (a) Taber, D. F.; Hennessy, M. J.; Louey, J. P. J. Org. Chem.
1
992, 57, 436. (b) Taber, D. F.; Hoerrner, R. S. J. Org.
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Synthesis 2002, No. 4, 471–474 ISSN 0039-7881 © Thieme Stuttgart · New York