Highly enantioselective intramolecular cyclopropanation reactions of N-Allylic-N-methyldiazoacetamides catalyzed by chiral dirhodium(II) carboxamidates

Article abstract of DOI:10.1021/jo9519219

Catalytic diazo decomposition of representative N-allylic-N- methyldiazoacetamides produced the corresponding intramolecular cyclopropanation products in good to excellent yields and with exceptional enantiocontrol. In the simplest case, with N-allyl-N-methyldiazoacetamide, catalysis by dirhodium(II) tetrakis[methyl 2-oxapyrrolidine-5(S)-carboxylate], Rh ₂(5(S)-MEPY)₄, achieved the highest yield and enantioselectivity (93% ee). Dirhodium(II) tetrakis[methyl 2-oxo-1-(3- phenylpropanoyl) imidazolidin-4(S)-carboxylate], Rh₂(4S)-MPPIM) ₄, was preferred for substituted N-allylic-N-methyldiazoacetamides from which 92-95% ee's were obtained in intramolecular cyclopropanation reactions (88-95% yields), even when the catalyst was employed in only 0.1 mol %. Competition with intramolecular dipolar cycloaddition was minimized with the use of Nmethyldiazoacetamides relative to N-tert-butyldiazoacetamides.

Full text of DOI:10.1021/jo9519219

J . Org. Chem. 1996, 61, 2179-2184
2179
High ly En a n tioselective In tr a m olecu la r Cyclop r op a n a tion
Rea ction s of N-Allylic-N-m eth yld ia zoa ceta m id es Ca ta lyzed by
Ch ir a l Dir h od iu m (II) Ca r boxa m id a tes
Michael P. Doyle* and Alexey V. Kalinin
Department of Chemistry, Trinity University, San Antonio, Texas 78212
Received October 27, 1995X
Catalytic diazo decomposition of representative N-allylic-N-methyldiazoacetamides produced the
corresponding intramolecular cyclopropanation products in good to excellent yields and with
exceptional enantiocontrol. In the simplest case, with N-allyl-N-methyldiazoacetamide, catalysis
by dirhodium(II) tetrakis[methyl 2-oxapyrrolidine-5(S)-carboxylate], Rh
highest yield and enantioselectivity (93% ee). Dirhodium(II) tetrakis[methyl 2-oxo-1-(3-phenyl-
propanoyl)imidazolidin-4(S)-carboxylate], Rh (4S)-MPPIM) , was preferred for substituted N-allylic-
2 4
(5(S)-MEPY) , achieved the
2
4
N-methyldiazoacetamides from which 92-95% ee’s were obtained in intramolecular cyclopropan-
ation reactions (88-95% yields), even when the catalyst was employed in only 0.1 mol %.
Competition with intramolecular dipolar cycloaddition was minimized with the use of N-
methyldiazoacetamides relative to N-tert-butyldiazoacetamides.
We recently reported that the homoallylic N-tert-butyl-
N-(3-buten-1-yl)diazoacetamides (1) underwent intra-
molecular cyclopropanation catalyzed by dirhodium(II)
catalytic cyclopropanation with N-allyldiazoacetamides,4
intramolecular reactions would be frustrated by the lack
of proximity of the double bond to the diazo or metal
carbene enter. However, if the substituent is methyl,
there was expected to be a balance between 3 and 4 so
that, relative to R ) t-Bu, dipolar cycloaddition might
occur on a time scale that was significantly less than that
for intramolecular cyclopropanation. We now wish to
report that N-allylic-N-methyldiazoacetamides undergo
intramolecular cyclopropanation with high enantiocontrol
and without extensive competition from intramolecular
dipolar cycloaddition.
tetrakis[methyl 2-oxapyrrolidine-5(S)-carboxylate], Rh
5(S)-MEPY) , or dirhodium(II) tetrakis[methyl 2-oxo-
oxazolidine-4(S)-carboxylate], Rh (4(S)-MEOX) , in good
2
-
(
4
2
4
yields and with enantiomeric excesses ranging from 60
1
to 90% (eq 1), but we were frustrated in our attempts to
Resu lts a n d Discu ssion
Diazoacetamides were prepared in good yields from
5
effect intramolecular cyclopropanation with their allylic
analogs by an unexpectedly facile [3 + 2] cycloaddition
to form pyrazolines.2 Only N,N-diallyldiazoacetamide
was competitively transformed to the intramolecular
cyclopropanation product, but its yield was low and its
enantiomeric excess was only 72%.1 The amide func-
tionality exacts a conformational rigidity on the diazo-
allylic bromides by methylamine substitution followed
by direct diazoacetyl transfer from succinimidyl diazo-
acetate (eq 3), for which we have developed an improved
6
3
acetamide that with a N-tert-butyl substituent favors 3,
which is suitably aligned for intramolecular cycloaddition
as well as for eventual intramolecular cyclopropanation.
We reasoned that if the tert-butyl group was replaced by
H (R ) t-Bu f R ) H, eq 2), the preferred conformation
method for synthesis. This diazoacetylation procedure
would be 4 and, as was demonstrated in attempted
is preferred over the diketene condensation-diazo trans-
X
Abstract published in Advance ACS Abstracts, February 15, 1996.
(4) Doyle, M. P.; Austin, R. E.; Bailey, A. S.; Dwyer, M. P.; Dyatkin,
A. B.; Kalinin, A. V.; Kwan, M. M. Y.; Liras, S.; Oalmann, C. J .; Pieters,
R. J .; Protopopova, M. N.; Raab, C. E.; Roos, G. H. P.; Zhou, Q.-L.;
Martin, S. F. J . Am. Chem. Soc. 1995, 117, 5763.
(5) Nordlander, J . E.; Catalane, D. B.; Eberline, T. H.; Farkas, L.
V.; Howe, R. S.; Stevens, R. M.; Tripoulas, N. A. Tetrahedron Lett. 1978,
4987.
(
1) Doyle, M. P.; Eismont, M. Y.; Protopopova, M. N.; Kwan, M. M.
Y. Tetrahedron 1994, 50, 1665.
2) (a) Sturm, H.; Ongania, K.-H.; Daly, J . J .; Kl o¨ tzer, W. Chem.
(
Ber. 1981, 114, 190. (b) Minami, T.; Kamitamari, M.; Utsunomiya,
T.; Tanaka, T.; Ichikawa, J . Bull. Chem. Soc. J pn. 1993, 66, 1496.
(3) (a) Regitz, M.; Mass, G. Aliphatic Diazo CompoundssProperties
and Synthesis; Academic Press: New York, 1986. (b) Challis, B. C.;
Latif, F. J . Chem. Soc., Perkin Trans. 1 1990, 1005.
(6) Quihia, A.; Ren e´ , L.; Guilhem, J .; Pascard, C.; Badet, B. J . Org.
Chem. 1993, 58, 1641.
0
022-3263/96/1961-2179$12.00/0 © 1996 American Chemical Society

2
180 J . Org. Chem., Vol. 61, No. 6, 1996
Doyle and Kalinin
fer-deacylation methodology1,7 because it avoids the
production of N-allylic diazoacetoacetamides which are
more susceptible than are N-allylic diazoacetamides
toward dipolar cycloaddition.2 Furthermore, succin-
imidyl diazoacetate is a stable, easily stored solid that is
Ta ble 1. Ca ta lytic In tr a m olecu la r Cyclop r op a n a tion of
N-Allyl-N-m eth yld ia zoa ceta m id e (8)a
catalyst
yield, %, of 9b
% ee of 9c
Rh2(5(S)-MEPY)4
62
45
23
20
33
41
93
86
56
75
Rh (4(S)-MEOX)4
2
highly selective toward diazoacetyl transfer to amines
Rh2(4(S)-MACIM)4
and phenols.6
Rh (4(S)-MPPIM)4
2
Rh2(cap)4
Rh2(OAc)4
Diazo decomposition of N-allyl-N-methyldiazoacet-
amide (8) was accomplished in refluxing CH Cl (eq 4)
2 2
a
Reactions were performed in refluxing CH2Cl2 using 1.0 mol
of catalyst. b Isolated yield of purified product. c Determined by
%
capillary GC with base line resolution on a Chiraldex G-TA
column.
for pyrazoline formation from 8 was approximately 25 h
at 22 °C. In refluxing chloroform, 10 was obtained in
quantitative yield within 2.5 h. Enantiomeric excesses
were determined by GC analyses on a chiral capillary
column, and unless the pyrazoline byproduct was com-
pletely separated from the catalytic cyclopropanation
product, reduced % ee values (up to 12%) were observed,
1
3
presumably due to dinitrogen loss from the pyrazoline.
The absolute configuration of 9 was established to be
R,5S by comparison (rotation and GC) of 9 with the
1
product from N-methylation of (1R,5S)-3-azabicyclo[3.1.0]-
hexan-2-one.4
Catalytic intramolecular cyclopropanation of represen-
tative substituted N-allylic-N-methyldiazoacetamides (eq
6
) occurred without noticeable competition from dipolar
with chiral dirhodium(II) carboxamidate catalysts chosen
to evaluate optimization of enantiocontrol: Rh (5(S)-
(4(S)-MEOX);9 dirhodium(II) tetrakis-
2
methyl 1-acetyl-2-oxoimidazolidine-4(S)-carboxylate], Rh -
2
8
MEPY)
4
;
Rh
2
[
1
0
(4(S)-MACIM)
4
;
and dirhodium(II) tetrakis[methyl 2-oxo-
1
Rh
-(3-phenylpropanoyl)imidazolidine-4(S)-carboxylate],
cycloaddition and produced cyclopropane-fused γ-lactams
11 in high yield and with exceptional enantiocontrol
(Table 2). The preferred catalyst was Rh (4(S)-MPPIM) ,
1
1
2
(4(S)-MPPIM)
4
.
Rhodium(II) acetate and rho-
1
2
2 4
dium(II) caprolactamate, Rh (cap) , catalyzed reactions
2
4
were performed to obtain racemic products and to esti-
mate the relative extent of competing reactions with the
use of achiral catalysts. As seen from Table 1, the
highest % ee and isolated yield were achieved with
which could be effectively employed in as little as 0.1 mol
% to achieve the highest levels of enantiocontrol and the
lowest amount of the competing product 12. Absolute
configurations are those depicted for 11a -d ; they were
inferred from 9 and from their sign of rotation relative
to that of their lactone analogs whose absolute configu-
ration is known.4
2 4
Rh (5(S)-MEPY) . Dipolar cycloaddition of 8 (eq 5) was
,8
The formation of 12 is consistent with stepwise in-
tramolecular electrophilic addition of the metal carbene
(13) to the carbon-carbon double bond (eq 7), forming
competitive with intramolecular cyclopropanation and
caused the lower than optimal yields of 9; the half-life
(
7) Doyle, M. P.; Pieters, R. J .; Taunton, J .; Pho, H. Q.; Padwa, A.;
Hertzog, D. L.; Precedo, L. J . Org. Chem. 1991, 56, 820.
8) Doyle, M. P.; Winchester, W. R.; Hoorn, J . A. A.; Lynch, V.;
Simonsen, S. H.; Ghosh, R. J . Am. Chem. Soc. 1993, 115, 9968.
9) Doyle, M. P.; Dyatkin, A. B.; Protopopova, M. N.; Yang, C. I.;
Miertschin, C. S.; Winchester, W. R.; Simonsen, S. H.; Lynch, V.;
Ghosh, R. Recl. Trav. Chim., Pays-Bas 1995, 114, 163.
(
an intermediate carbocation 14 that produces 12 follow-
ing 1,2-hydrogen migration and elimination of ML . An
n
identical transformation to that described in eq 7 has
(
1
4
(
10) Doyle, M. P.; Dyatkin, A. B.; Roos, G. H. P.; Ca n˜ as, F.; Pierson,
D. A.; Basten, A. van; M u¨ ller, P.; Polleux, P. J . Am. Chem. Soc. 1994,
16, 4507.
11) Doyle, M. P.; Protopopova, M. N.; Zhou, Q.-L.; Bode, J . W.;
Simonsen, S. H.; Lynch, V. J . Org. Chem. 1995, 60, 6654.
12) Doyle, M. P.; Westrum, L. J .; Wolthuis, W. N. E.; See, M. M.;
Boone, W. P.; Bagheri, V.; Pearson, M. M. J . Am. Chem. Soc. 1993,
15, 958.
1
(13) Doyle, M. P.; Dorow, R. L.; Tamblyn, W. H. J . Org. Chem. 1982,
47, 4059.
(14) Similar processes, including the well-known “apparent” allylic
C-H insertion, have been previously observed: (a) Alonso, M. E.;
Fernandez, R. Tetrahedron 1989, 45, 3313. (b) Doyle, M. P. Chem.
Rev. 1986, 89, 919.
(
(
1

Reactions of N-Allylic-N-methyldiazoacetamides
J . Org. Chem., Vol. 61, No. 6, 1996 2181
Ta ble 2. In flu en ce of Dir h od iu m (II) Ca ta lysts on P r od u ct Selectivity in In tr a m olecu la r Cyclop r op a n a tion
Rea ction s of 7a
b
% ee of 11c
confignd
7
a
Rt
Rc
catalyst
yield, %
11:12
Me
Me
Rh2(5(S)-MEPY)4
Rh2(4(S)-MEOX)4
Rh2(4(S)-MACIM)4
Rh2(4(S)-MPPIM)4e
Rh2(cap)4
92
91
82
88
49
70
93
93
93
56
60
95
86
88
59
54
98
94
95
67
77
98:2
83:17
>99:<1
>99:<1
97:3
82:18
>99:<1
98:2
86
94
81
94
(1S,5R)
(1S,5R)
(1S,5R)
(1S,5R)
Rh2(OAc)4
b
c
d
n-Pr
H
Rh2(5(S)-MEPY)4
Rh2(4(S)-MEOX)4
Rh2(4(S)-MPPIM)4
Rh2(cap)4
86
57
92
(1R,5S)
(1R,5S)
(1R,5S)
99:1
96:4
Rh2(OAc)4
97:1f
99:1
H
n-Pr
Me
Rh2(5(S)-MEPY)4
Rh2(4(S)-MEOX)4
Rh2(4(S)-MPPIM)4
Rh2(cap)4
90
92
95
(1R,5S)
(1R,5S)
(1R,5S)
97:3
99:1
99:1
87:13
98:2
83:17
>99:<1
97:3
Rh2(OAc)4
(CH2)2CHdCMe2
Rh2(5(S)-MEPY)4
Rh2(4(S)-MEOX)4
Rh2(4(S)-MPPIM)4g
Rh2(cap)4
92
94
93
(1S,5R)
(1S,5R)
(1S,5R)
Rh2(OAc)4
79:21
a
b
Reactions were performed in refluxing CH2Cl2 using, unless specified otherwise, 1.0 mol % of catalyst. Isolated yield of purified
c
d
product (11 + 12). Determined by capillary GC on a Chiraldex G-TA column with base line resolution. Absolute configurations are as
depicted for 11a -d ; change in notation results from change in priorities by substituents. Catalyst amount was 0.1 mol %. f Two additional
e
g
products, 1% each (not identified), were detected. Catalyst amount was 0.2 mol %.
Ta ble 3. In flu en ce of Dir h od iu m (II) Ca ta lysts on
P r od u ct Selectivity in In tr a m olecu la r Rea ction s of
N-(2-Meth yl-2-p r op en -1-yl)-N-m eth yld ia zoa ceta m id ea
cyclopropanation reactions catalyzed by chiral dirho-
dium(II) carboxamidates, and its N-ethyldiazoacetamide
analog behaved similarly. Diazo decomposition of N-ethyl-
N-(2-methyl-2-propen-1-yl)diazoacetamide (15) produced
the product from intramolecular cyclopropanation (16)
in good yield (eq 8), but enantioselectivity did not exceed
relative yield
catalyst
isolated yield, % 16 17
18 % ee 16b
Rh2(5(S)-MEPY)4
Rh2(4(S)-MEOX)4
Rh2(4(S)-MACIM)4
Rh2(4(S)-MPPIM)4
Rh2(cap)4
78
81
86
85
83
71
98 <1
92 <1
2
8
<1
<1
35
7
48
44
c
95
94
80
70
5
6
20 <1
30 <1
Rh2(OAc)4
a
Reactions were performed in refluxing CH2Cl2 using 1.0 mol
b
%
of catalyst. Determined by capillary GC with base line resolu-
tion on a Chiraldex B-PH column. The predominant configuration
was opposite that from other entries in this table.
c
been reported in intramolecular cyclopropanation reac-
tions of 3-methyl-2-buten-1-yl diazoacetate, the ester
analog of 7a , particularly with chiral dirhodium carbox-
5
0% ee (Table 3). In addition, the product from carbene
8
insertion into a methyl C-H bond of the N-ethyl sub-
stituent (17) was a major competing process with use of
the achiral catalysts, although not with the chiral
amidates without pendent carbomethoxy substituents.
That 7a and 7d gave the highest relative yields of 12 is
also consistent with the stepwise carbocation mechanism
for its formation.
The highest levels of enantiocontrol achieved with
chiral dirhodium(II) carboxamidates for the formation of
catalysts. Furthermore, in reactions catalyzed by Rh
2
-
(5(S)-MEPY) and Rh (4(S)-MEOX) a product (18) con-
4
2
4
sistent with intramolecular electrophilic addition of the
metal carbene to the carbon-carbon double bond was
detected. This product conforms to the chairlike transi-
tion state orientation (19) previously described for cata-
9
and 11 are only 2-4% ee lower than those previously
4,15
reported for their lactone analogs,
and the absolute
configuration of products formed by intramolecular cy-
clopropanation of diazoacetamides with the same catalyst
configuration is identical. For example, the S-series of
chiral dirhodium(II) carboxamidate catalysts forms
(1R,5S)-9, whereas the R-series provides (1S,5R)-9 with
the same level of enantiocontrol. The only limitation with
N-allylic-N-methyldiazoacetamide is dipolar cycloaddition
which in our hands precluded intramolecular cyclopro-
lytic cyclopropanation of 2-methyl-2-propen-1-yl diazo-
acetate in which initial interaction occurs at the terminal
carbon in order to optimize carbocation stabilization.
t
c
panation of 7 (R ) Ph, R ) H).
-Methyl-2-propen-1-yl diazoacetate was previously
2
shown to be an anomoly among allylic diazoacetates in
its resistance to high enantiocontrol in intramolecular
Exp er im en ta l Section
Gen er a l P r oced u r es. 1H NMR (300 MHz) and 13C NMR
(
15) Doyle, M. P.; Zhou, Q.-L.; Dyatkin, A. B.; Ruppar, D. A.
(75 MHz) spectra were obtained as solutions in CDCl
3
, unless
Tetrahedron Lett. 1995, 36, 7579.
indicated otherwise, and chemical shifts are reported in parts

2
182 J . Org. Chem., Vol. 61, No. 6, 1996
Doyle and Kalinin
per million (ppm, δ) downfield from internal Me
4
Si (TMS).
2 H), 3.25-3.21 (comp, 2 H), 2.43 (s, 3 H), 2.08-2.00 (comp, 2
H), 1.39 (hex, J ) 7.1 Hz, 2 H), 1.12 (br s, 1 H), 0.91 (t, J )
7.3 Hz, 3 H); 13C NMR δ 131.8, 127.8, 48.1, 35.8, 29.3, 22.6,
Mass spectra were obtained using electron ionization on a
quadrupole instrument. Infrared spectra were recorded as a
thin film on sodium chloride plates, and adsorptions are
13.5; IR (film) 3291 (br, NH), 3012, 2960, 2931, 2872, 2845,
-
1
-1
reported in wavenumbers (cm ). Elemental analyses were
performed at Texas Analytical Laboratories, Inc. The prepa-
7
2786, 1655 (CdC) cm . Anal. Calcd for C H15N: C, 74.27;
H, 13.36; N, 12.38. Found: C, 74.26; H, 13.28; N, 12.24.
Gen er a l P r oced u r e for th e P r ep a r a tion of N-Allylic-
N-m eth yld ia zoa ceta m id es. To an ice-bath cooled solution
of the N-allylic-N-methylamine (9.6 mmol) and triethylamine
8
9
rations of Rh
2
(5(S)-MEPY)
2
4
,
Rh
2
(4(S)-MEOX)
4
,
Rh
2
(4(S)-
4
11
12
MACIM)
4
,
Rh
(4(S)-MPPIM)
4
,
2 4
and Rh (cap)
have been
previously reported. Dichloromethane was distilled from
calcium hydride prior to use. N-methyl-N-(2-propen-1-yl)-
amine and N-ethyl-N-(2-methyl-2-propen-1-yl)amine were com-
mercially available.
2 2
(1.21 g, 12.0 mmol) in 20 mL of anhydrous CH Cl was added
over 10 min a solution of succinimidyl diazoacetate (1.46 g,
7.98 mmol) in 30 mL of the same solvent. The mixture was
stirred for 30 min at 0 °C and then for 1 h at room tempera-
ture. After concentration of the solution under vacuum, the
residue was purified by flash chromatography on silica gel (1:1
hexanes:EtOAc) to yield the yellow diazoacetamide. All opera-
tions were conducted at or below room temperature, and the
diazoacetamides were stired in a refrigerator. NMR spectra
revealed significant broadening of absorptions for atoms near
nitrogen, suggesting restricted rotation.
Su ccin im id yl Dia zoa ceta te. Glyoxylic acid chloride (p-
1
6
toluenesulfonyl)hydrazone (103.3 g, 0.500 mol) in 1.00 L of
CH Cl was added over 2 h to a mechanically stirred suspen-
sion of N-hydroxysuccinimide (63.25 g, 0.550 mol) and Na CO
79.5 g, 0.750 mol) in 0.75 L of dry CH Cl maintained at 0
C. The resulting mixture was stirred for an additional hour
2
2
2
3
(
2
2
°
and then warmed to room temperature, where it was main-
tained for 3 h, after which time it was filtered through a sand
plug and then Celite. The filtrate was concentrated under
reduced pressure to provide crude succinimidyl diazoacetate
N-Met h yl-N-(3-m et h yl-2-b u t en -1-yl)d ia zoa cet a m id e
(7a ): prepared in 81% yield; R
) 0.46 (1:1 hexanes:EtOAc);
f
1
as a brown-yellow solid. Recrystallization from CH
2
Cl
2
/
H NMR δ 5.15-5.08 (m, 1 H), 4.94 (s, 1 H), 4.00-3.75 (br m,
2 H), 2.84 (br s, 3 H), 1.74 (s, 3 H), 1.69 (s, 3 H); 13C NMR δ
hexanes gave light yellow crystalline product (43.0 g, 0.235
6
mmol, 47% yield): mp 113.5-115.0 °C (lit. mp 119-120 °C);
165.3, 135.9, 119.4, 46.0, 46.0, 33.5, 25.4, 17.5; IR (film) 2102
1
-1
H NMR δ 5.13 (br s, 1 H), 2.85 (s, 4 H).
2 8 13 3
(CdN ), 1618 (CdO) cm . Anal. Calcd for C H N O: C,
5
7.46; H, 7.83; N, 25.13. Found: C, 57.41; H, 7.89; N, 25.03.
N -(t r a n s-2-H e x e n -1-y l)-N -m e t h y ld ia zo a c e t a m id e
7b): prepared in 86% yield; R ) 0.51 (1:1 hexanes:EtOAc);
H NMR δ 5.64-5.53 (m, 1 H), 5.41-5.30 (m, 1 H), 4.95 (s, 1
H), 4.00-3.60 (br m, 2 H), 3.00-2.70 (br s, 3 H), 2.07-1.98
Gen er a l P r oced u r e for th e P r ep a r a tion of N-Allylic-
5
N-m eth yla m in es. To a stirred suspension of KH (35 wt %
(
f
in mineral oil; 6.86 g, 60.0 mmol) in 250 mL of absolute ether
under a nitrogen atmosphere was added a solution of N-
methyltrifluoroacetamide (6.35 g, 50.0 mmol) and 0.13 g (0.50
mmol) of 18-crown-6 in 75 mL of anhydrous ether dropwise
over 30 min. After the mixture was stirred for an additional
hour, the allyl bromide (70.0 mmol) was added dropwise over
1
(
3
2
comp, 2 H), 1.40 (hex, J ) 7.3 Hz, 2 H), 0.89 (t, J ) 7.3 Hz,
H); 13C NMR δ 165.6, 133.9, 124.3, 50.3 (br), 46.1, 34.1, 33.6,
1
-
2.1, 13.4; IR (film) 2100 (CdN
O: C, 59.64; H, 8.34; N, 23.18. Found: C,
9.56; H, 8.39; N, 23.12.
N-(cis-2-Hexen -1-yl)-N-m eth yldiazoacetam ide (7c): pre-
2
), 1605 (CdO) cm . Anal.
9 15 3
Calcd for C H N
5
3
0 min, and the resulting mixture was refluxed with vigorous
stirring for 24 h. Cautious acidification was performed by
adding 10% aqueous HCl at 0 °C, the organic layer was
separated, and solvent was removed under reduced pressure.
The crude N-allyl-N-methyl trifluoroacetamide was then treated
with a solution of KOH (4.20 g, 75.0 mmol) in 100 mL of 1:1
1
pared in 82% yield; R
f
) 0.55 (1:1 hexanes:EtOAc); H NMR δ
.66-5.55 (m, 1 H), 5.38-5.28 (m, 1 H), 4.95 (s, 1 H), 4.10-
.80 (br m, 2 H), 2.95-2.80 (br s, 3 H), 2.12-2.04 (comp, 2 H),
5
3
1
1
3
.42 (hex, J ) 7.3 Hz, 2 H), 0.93 (t, J ) 7.3 Hz, 3 H); C NMR
MeOH:H
2
O and stirred for 3 h at 25 °C. After acidification
δ 165.1, 133.2, 124.2, 45.8 (br), 45.6, 33.1, 28.8, 22.2, 13.1; IR
with concd HCl at 0 °C, methanol was removed under reduced
pressure, and the resulting aqueous solution was washed twice
with 50-mL portions of ether. The amine hydrochloride in
water was combined with 50 mL of ether, and the free amine
was generated by the addition of KOH pellets at 0 °C. The
etheral solution of the amine was separated and dried over
KOH, and the solvent was removed by distillation at atmo-
spheric pressure. The residue was distilled under vacuum to
provide the pure amine as a colorless liquid. N-Meth yl-N-
-
1
(film) 2104 (CdN
2
), 1603 (CdO) cm
.
Anal. Calcd for
9 15 3
C H N
O: C, 59.64; H, 8.34; N, 23.18. Found: C, 59.52; H,
8
.38; N, 23.10.
N-(tr a n s-3,7-Dim et h yl-2,6-d ien -1-yl)-N-m et h yld ia zo-
a ceta m id e (7d ): prepared in 93% yield; R ) 0.74 (1:1
f
1
hexanes:EtOAc); H NMR δ 5.14-5.02 (comp, 2 H), 4.95 (s, 1
H), 4.05-3.70 (br m, 2 H), 2.92-2.77 (br s, 3 H), 2.15-1.98
(comp, 4 H), 1.68 (s, 6 H), 1.60 (s, 3 H); 13C NMR δ 165.2, 139.3,
131.3, 123.5, 119.2, 45.9, 45.8 (br), 39.2, 33.3, 26.0, 25.3, 17.3,
1
7
(
3-m eth yl-2-bu ten -1-yl)a m in e (7a ), bp 116-118 °C, was
1
15.8; IR (film) 2103 (CdN ), 1608 (CdO) cm-1. Anal. Calcd
prepared in 61% yield: H NMR δ 5.29-5.21 (m, 1 H), 3.16
d, J ) 6.9 Hz, 2 H), 2.41 (s, 3 H), 1.72 (br s, 3 H), 1.65 (s, 3
H), 1.10 (br s, 1 H). N-(tr a n s-3,7-Dim eth yl-2,6-octa d ien -
2
(
21 3
for C13H N O: C, 66.35; H, 8.99; N, 17.86. Found: C, 66.21;
H, 9.07; N, 17.73.
N-Meth yl-N-(2-p r op en -1-yl)d ia zoa ceta m id e (8): pre-
1
8
1
-yl)-N-m eth yla m in e (7d ), bp 124-126 °C (25 Torr), was
1
prepared in 90% yield: H NMR δ 5.29-5.21 (m, 1 H), 5.14-
pared in 84% yield; R
unstable and used immediately after chromatography;
NMR δ 5.80-5.66 (m, 1 H), 5.21-5.10 (comp, 2 H), 4.95 (s, 1
f
) 0.35 (1:1 hexanes:EtOAc); thermally
1
5
1
.06 (m, 1 H), 3.18 (d, J ) 6.7 Hz, 2 H), 2.42 (s, 3 H), 2.15-
H
.97 (comp, 4 H), 1.68 (s, 3 H), 1.65 (s, 3 H), 1.60 (s, 3 H), 1.31
1
3
(s, 1 H).
H), 4.10-3.60 (br m, 2 H), 2.86 (br s, 3 H); C NMR δ 165.0,
1
2
31.9, 115.9, 49.9 (br), 45.3, 33.1; IR (film) 2104 (CdN ), 1607
N-(tr a n s-2-Hexen -1-yl)-N-m eth yla m in e (7b): bp 81-84
-
1
1
(CdO) cm .
°
C (105 Torr), prepared in 59% yield; H NMR δ 5.65-5.45
3
,3r,4,5,6,6r-Hexah ydr o-5-m eth ylpyr r olo[3,4-c]pyr azol-
-on e (10). A solution of 0.139 g (1.00 mmol) of 8 in 5 mL of
CHCl was refluxed for 2.5 h. After evaporation of the solvent,
(
(
(
2
2
comp, 2 H), 3.16-3.13 (comp, 2 H), 2.41 (s, 3 H), 2.04-1.96
6
comp, 2 H), 1.39 (hex, J ) 7.4 Hz, 2 H), 1.11 (br s, 1 H), 0.90
t, J ) 7.3 Hz, 3 H); 1 C NMR δ 132.5, 128.2, 53.7, 35.7, 34.4,
3
3
1
1
0 was obtained in quantitative yield as a colorless oil:
NMR δ 5.50 (dddd, J ) 9.2, 3.3, 1.6, 0.8 Hz, 1 H), 4.84 (ddd, J
18.4, 9.2, 1.6 Hz, 1 H), 4.60 (ddd, J ) 18.4, 3.3, 2.3 Hz, 1 H),
.65 (dd, J ) 10.5, 8.6 Hz, 1 H), 2.98 (dd, J ) 10.5, 3.4 Hz, 1
H), 2.91-2.79 (m, 1 H), 2.82 (s, 3 H); C NMR δ 165.8, 95.5,
5.2, 53.9, 28.9, 26.0; IR (film) 1678 (CdO) cm . Anal. Calcd
H
2.4, 13.5; IR (film) 3289 (br, NH), 2959, 2928, 2873, 2843,
-
1
7
788, 1669 (CdC) cm . Anal. Calcd for C H15N: C, 74.27;
)
3
H, 13.36; N, 12.38. Found: C, 74.18; H, 13.23; N, 12.31.
N-(cis-2-Hexen -1-yl)-N-m eth yla m in e (7c): bp 81-84 °C
1
3
1
(
105 Torr), prepared in 67% yield; H NMR δ 5.56-5.41 (comp,
-1
8
for C O: C, 51.79; H, 6.52; N, 30.19. Found: C, 51.86;
H, 6.41; N, 30.27.
N -E t h yl-N -(2-m e t h yl-2-p r op e n -1-yl)d ia zoa ce t a m id e
6
9 3
H N
(
16) Blankley, J .; Sauter, F. J .; House, H. O. Organic Syntheses;
Wiley: New York, 1973; Collect. Vol. V, p 259.
17) Grigoryan, D. V.; Kazaryan, A. T.; Martirosyan, G. T.; Babayan,
A. T. Zh. Org. Khim. 1971, 6, 1390.
18) Deshpande, R. S.; Tipnis, H. P.; Kulkarni, V. M. Indian J .
Chem., Sect. B 1976, 14B, 979.
(
(
15): prepared in 91% yield; R
f
) 0.26 (3:1 hexanes:EtOAc);
H NMR δ 4.93 (br s, 1 H), 4.90 (s, 1 H), 4.82 (s, 1 H), 4.00-
3.50 (br m, 2 H), 3.50-3.20 (br m, 2 H), 1.71 (s, 3 H), 1.14 (t,
1
(

Reactions of N-Allylic-N-methyldiazoacetamides
J . Org. Chem., Vol. 61, No. 6, 1996 2183
(100), 53 (91). Anal. Calcd for C
15NO: C, 70.55; H, 9.87;
J ) 7.1 Hz, 3 H); 13C NMR δ 165.5, 140.5 (br), 111.7 (br), 51.8
9
H
(
br), 46.2, 41.3, 19.7, 13.1; IR (film) 2111 (CdN
2
), 1609 (CdO)
N, 9.14. Found: C, 70.51; H, 9.82; N, 9.21.
-
1
cm . Anal. Calcd for C
8
H
13
N
3
O: C, 57.47; H, 7.83; N, 25.13.
1-Meth yl-4-n -bu tyl-1,5-d ih yd r o-2H-p yr r ol-2-on e (12b )
Found: C, 57.56; H, 7.81; N, 25.07.
Ca ta lytic Cyclop r op a n a tion of N-Allylic-N-m eth yld i-
a zoa ceta m id es. Gen er a l P r oced u r e. A solution of the
12c) was isolated by column chromatography on silica gel (2:1
EtOAc:hexanes, R
f
) 0.27) as a colorless oil: 1H NMR (C
D )
6 6
δ 5.74 (quin, J ) 1.5 Hz, 1 H), 2.87-2.85 (m, 2 H), 2.63 (s, 3
H), 1.73-1.67 (comp, 2 H), 1.10-1.00 (comp, 4 H), 0.75 (t, J )
diazoacetamide (1.00 mmol) in 10 mL of anhydrous CH
was added via syringe pump over 10 h (1.0 mL/h) to a solution
of the catalyst (0.1-1.0 mol %) in 10 mL of CH Cl . (With 8
2 2
Cl
7
2
.0 Hz, 3 H); 13C NMR (C
D ) δ 171.2, 158.2, 122.5, 55.4, 29.8,
6 6
1
-
9.1, 28.4, 22.5, 13.8; IR (film) 1677 (CdO) cm ; mass
2
2
spectrum, m/ z (rel abundance) 154 (7, M + 1), 153 (61, M),
a 5 h addition time was employed.) After addition was
complete, the reaction solution was filtered through a silica
gel plug to remove the dirhodium(II) catalysts, and the solvent
was then evaporated under reduced pressure. Analyses by GC
and NMR were performed on the residue before distillation
or chromatographic purification.
1
5
11 (23), 110 (100), 97 (32), 96 (95), 82 (32), 68 (24), 67 (23),
5 (30).
[1R-(1r,5r,6r)]-6-n -P r op yl-3-a za bicyclo[3.1.0]h exa n -2-
on e (11c): colorless oil, bp 80-90 °C (0.1 Torr); chromato-
graphic purification with 1:2 hexanes:EtOAc; enantiomer
separation on a 30-m Chiraldex G-TA column operated at 135
(
1R,5S)-3-Meth yl-3-azabicyclo[3.1.0]h exan -2-on e (9): col-
orless oil, bp 70-75 °C (0.2 Torr); enantiomer separation on a
0-m Chiraldex G-TA column operated at 140 °C, 11.2 min
for the major isomer, (1R,5S)-9, and 14.6 min for the minor
isomer, (1S,5R)-9, from reaction catalyzed by Rh
(5(S)-
) for 93% ee; H NMR
°
C, 24.5 min for the major isomer, (1R)-11c, and 28.3 min for
the minor isomer, (1S)-11c, from reaction with Rh (4(S)-
) for 95% ee; H NMR
2
3
1
MPPIM)
4
: [R]20
D
) +78.6 (c 1.51, CHCl
3
δ 3.54 (dd, J ) 10.9, 6.5 Hz, 1 H), 3.11 (d, J ) 10.9 Hz, 1 H),
2.74 (s, 3 H), 2.06-1.99 (m, 1 H), 1.83 (q, J ) 6.5 Hz, 1 H),
1
2
2
0
1
MEPY)
4
: [R]
D
) +59.9 (c 2.95, CHCl
3
.54-1.38 (comp, 2 H), 1.26-1.12 (comp, 3 H), 0.95 (t, J ) 7.4
δ 3.52 (dd, J ) 10.3, 5.7 Hz, 1 H), 3.28 (dd, J ) 10.3, 1.8 Hz,
13
Hz, 3 H); C NMR δ 172.5, 47.4, 28.2, 24.9, 24.2, 22.0, 21.1,
1
8
H), 2.74 (s, 3 H), 1.94-1.79 (comp, 2 H), 1.09 (ddd, J ) 8.0,
-
1
.0, 4.5 Hz, 1 H), 0.59 (ddd, J ) 4.5, 4.5, 3.2 Hz, 1 H); 13
16.0, 13.7; IR (film) 1685 (CdO) cm ; mass spectrum, m/ z
rel abundance) 154 (5, M + 1), 153 (31, M), 152 (7, M - 1),
138 (10), 124 (15), 111 (17), 110 (100), 98 (86), 97 (62), 96 (39),
2 (32), 81 (91), 69 (38), 68 (63), 67 (76), 55 (64), 54 (94), 53
77). Anal. Calcd for C 15NO: C, 70.55; H, 9.87; N, 9.14.
Found: C, 70.46; H, 9.81; N, 9.12.
1S-(1r,5r)]-6r-Met h yl-6â-(4-m et h yl-3-p en t en -1-yl)-3-
a za bicyclo[3.1.0]h exa n -3-on e (11d ): colorless oil, bp 120-
25 °C (0.25 Torr); chromatographic purification with 1:2
C
(
NMR δ 175.1, 51.4, 29.2, 20.2, 12.8, 11.8; IR (film) 1679 (CdO)
-1
cm ; mass spectrum, m/ z (rel abundance) 112 (8, M + 1), 111
8
(
(
8
100, M), 110 (39, M - 1), 96 (15), 83 (19), 82 (35), 68 (37), 55
52), 54 (37), 53 (22). Anal. Calcd for C NO: C, 64.80; H,
.16; N, 12.60. Found: C, 64.80; H, 8.10; N, 12.56.
Treatment of (1R,5S)-3-azabicyclo[3.1.0]hexan-2-one with
(
9
H
6
H
9
[
4
MeI (NaH/THF, 25 °C; 92% yield) produced 9 whose specific
rotation and chromatographic analysis confirmed the absolute
1
hexanes:EtOAc; enantiomer separation on a 30-m Chiraldex
G-TA column operated at 140 °C, 94.1 min for the major
ismoer, (1S)-11d , and 98.8 min for the minor isomer, (1R)-
configuration of the product from Rh
diazo decomposition of 8 as (1R,5S)-9: [R]
CHCl ) for 93% ee.
1S ,5R )-3,6,6-Tr im e t h yl-3-a za b icyclo[3.1.0]h e xa n -2-
2
(5(S)-MEPY)
4
-catalyzed
2
0
D
) +49.0 (c 1.08,
3
: [R]20
1
2
1d , from reaction with Rh
2
(4(S)-MEOX)
4
D
) +66.1 (c
(
1
.41, CHCl ) for 94.5% ee; H NMR δ 5.10-5.02 (m, 1 H), 3.53
3
on e (11a ): colorless oil, bp 75-80 °C (0.4 Torr); chromato-
graphic purification with 1:4 hexanes:EtOAc; enantiomer
separation on a 30-m Chiraldex G-TA column operated at 130
(
3
1
dd, J ) 11.0, 6.6 Hz, 1 H), 3.08 (d, J ) 11.0 Hz, 1 H), 2.73 (s,
H), 2.15-2.00 (comp, 2 H), 1.80 (dd, J ) 6.6, 1.8 H, 1 H),
.67 (s, 3 H), 1.60 (s, 3 H), 1.38-1.14 (comp, 2 H), 0.97 (s, 3
°
C, 23.0 min for the minor isomer, (1R,5S)-11a , and 25.3 min
for the major isomer, (1S,5R)-11a, from reactions with Rh (4(S)-
) for 94% ee;
13
H); C NMR δ 172.7, 131.7, 123.7, 48.1, 39.7, 32.3, 28.5, 25.6,
2
-1
2
5.6, 24.9, 23.2, 17.5, 11.0; IR (film) 1686 (CdO) cm ; mass
spectrum, m/ z (rel abundance) 208 (9, M + 1), 207 (48 M),
92 (13), 164 (29), 151 (17), 138 (56), 125 (51), 124 (82), 110
56), 99 (46), 98 (100) 95 (47), 82 (45), 81 (53), 79 (62), 69 (100),
7 (85), 53 (83). Anal. Calcd for C13 21NO: C, 75.31; H, 10.21;
N, 6.76. Found: C, 75.25; H, 10.13; N, 6.68.
-Met h yl-4-(6-m et h yl-5-h ep t en -2-yl)-1,5-d ih yd r o-2H -
2
1
MEOX)
4
(94% ee): [R]
D
) +100.4 (c 2.78, CHCl
3
1
H NMR δ 3.52 (dd, J ) 10.9, 6.6 Hz, 1 H), 3.10 (d, J ) 10.9
1
(
6
Hz, 1 H), 2.73 (s, 3 H), 1.79 (dd, J ) 6.6, 1.8 Hz, 1 H), 1.60 (t,
1
3
J ) 6.6 Hz, 1 H), 1.10 (s, 3 H), 0.99 (s, 3 H); C NMR δ 172.7,
H
4
8.2, 33.1, 28.5, 25.6, 23.9, 21.5, 13.7; IR (film) 1667 (CdO)
-
1
cm ; mass spectrum, m/ z (rel abundance) 140 (16 M + 1),
1
1
(
(
39 (99, M), 138 (18, M - 1), 124 (36), 111 (25), 98 (97), 97
34), 96 (60), 83 (24), 82 (100), 81 (77), 68 (69), 67 (100), 55
48), 54 (44), 53 (66). Anal. Calcd for C 13NO: C, 69.03; H,
.41; N, 10.06. Found: C, 68.95; H, 9.31; N, 9.98.
-Met h yl-1-(2-m et h ylet h yl)-1,5-d ih yd r o-2H -p yr r ol-2-
p yr r ol-2-on e (12d ) was isolated by column chromatography
1
on silica gel (2:1 EtOAc:hexanes) as a colorless oil: H NMR
8
H
(
1
1
C
6
D
6
) δ 5.78 (q, J ) 1.4 Hz, 1 H), 5.04 (t hept, J ) 7.1, 1.4 Hz,
9
H), 3.00-2.98 (m, 2 H), 2.63 (s, 3 H), 2.03 (hex, J ) 7.0 Hz,
H), 1.82 (q, J ) 7.3 Hz, 2 H), 1.66 (q, J ) 1.4 Hz, 3 H), 1.49
1
on e (12a ) was isolated by column chromatography on silica
(
d, J ) 0.9 Hz, 3 H), 1.30-1.05 (comp, 2 H), 0.74 (d, J ) 7.0
1
gel (1:4 EtOAc:hexanes) as a colorless oil: H NMR δ 5.83-
13
Hz, 3 H); C NMR (C
6 6
D ) δ 171.0, 162.9, 131.8, 124.3, 121.9,
5
7
1
.81 (m, 1 H), 3.88 (s, 2 H), 3.01 (s, 3 H), 2.62 (d hept, J ) 1.4,
5
3.8, 35.9, 33.8, 28.4, 25.82, 25.78, 19.3, 17.7; IR (film) 1683
.0 Hz, 1 H), 1.17 (d, J ) 7.0 Hz, 6 H); 13C NMR δ 172.3, 165.1,
-1
(CdO), 1621 (CdC) cm ; mass spectrum, m/ z (rel abundance)
-
1
20.4, 55.0, 29.03, 28.98, 21.5; IR (film) 1670 (CdO) cm ; mass
2
08 (4, M + 1), 207 (17, M), 192 (9), 164 (11), 150 (25), 138
spectrum, m/ z (rel abundance) 140 (4, M + 1), 139 (36, M),
38 (4, M - 1), 124 (60), 97 (59), 96 (100), 81 (12), 67 (17), 53
19).
1R-(1r,5r,6â)]-6-n -P r op yl-3-a za bicyclo[3.1.0]h exa n -2-
(32), 125 (52), 124 (100), 110 (26), 94 (18), 69 (24), 55 (22), 53
23).
1
(
(
(
1R,5S)-3-E t h yl-5-m et h yl-3-a za b icyclo[3.1.0]h exa n -2-
[
on e (16): colorless oil, bp 72-75 °C (0.15 Torr); chromato-
graphic purification with 1:2 hexanes:EtOAc; enantiomer
separation on a 30-m Chiraldex B-PH column operated at 90
°C, 76.9 min for the major isomer, (1R,5S)-16, and 84.2 min
for the minor isomer (1S,5R)-16, from reaction with
on e (11b): colorless oil, bp 80-85 °C (0.15 Torr); chromato-
graphic purification with 1:2 hexanes:EtOAc; enantiomer
separation on a 30-m Chiraldex G-TA column operated at 135
°
C, 22.2 min for the major isomer, (1R)-11b, and 28.2 min for
the minor isomer, (1S)-11b, from reaction with Rh (4(S)-
) for 92% ee; H NMR
: [R]20
2
Rh
2
(4(S)-MACIM)
4
D
3
) -5.1 (c 3.13, CHCl ) for 48% ee;
2
0
1
1
MPPIM)
4
: [R]
D
) +57.4 (c 1.99, CHCl
3
H NMR δ 3.35-3.11 (comp, 4 H), 1.67 (ddd, J ) 8.5, 3.2, 1.7
Hz, 1 H), 1.33 (s, 3 H), 1.05 (t, J ) 7.2 Hz, 3 H), 0.99 (dd, J )
8.5, 4.4 Hz, 1 H), 0.69 (dd, J ) 4.4, 3.2 Hz, 1 H); 13C NMR δ
175.2, 53.6, 36.6, 27.0, 19.6, 19.1, 19.0, 12.7; IR (film) 1673
δ 3.48 (dd, J ) 10.3, 5.9 Hz, 1 H), 3.27 (dd, J ) 10.3, 1.5 Hz,
1
)
3
H), 2.72 (s, 3 H), 1.69 (dt, J ) 6.2, 2.1 Hz, 1 H), 1.60 (dt, J
6.2, 3.6 Hz, 1 H), 1.51-1.17 (comp, 4 H), 0.93 (t, J ) 7.0 Hz,
1
3
-1
H); C NMR δ 174.5, 51.4, 33.5, 29.1, 26.9, 26.4, 21.9, 18.3,
(CdO) cm ; mass spectrum, m/ e (rel abundance) 140 (7, M
-
1
1
3.7; IR (film) 1685 (CdO) cm ; mass spectrum, m/ z (rel
+ 1), 139 (75, M), 138 (9, M - 1), 124 (89), 111 (25), 96 (100),
95 (30), 68 (63), 67 (72), 55 (77), 53 (46). Anal. Calcd for C H -
8 13
NO: C, 69.03; H, 9.41; N, 10.06. Found: C, 69.10; H, 9.51; N,
9.97.
abundance) 154 (15, M + 1), 153 (98, M), 152 (18, M - 1), 138
(22), 124 (32), 111 (70), 110 (96), 99 (44), 98 (89), 97 (47), 96
94), 82 (47), 81 (100), 69 (54), 68 (92), 67 (100), 55 (89), 55
(

2
184 J . Org. Chem., Vol. 61, No. 6, 1996
-(2-Meth yl-2-pr open -1-yl)pyr r olidin -2-on e (17) was iden-
Doyle and Kalinin
1
(CdO) cm-1; mass spectrum, m/ z (rel abundance) 140 (4, M
+ 1), 139 (50, M), 138 (4, M - 1), 124 (47), 110 (10), 95 (32),
82 (100), 81 (33), 67 (23), 58 (25), 54 (48), 53 (25).
1
tified from its NMR spectra: H NMR δ 4.89-4.84 (m, 1 H),
4
.80-4.77 (m, 1 H), 3.80 (br s, 2 H), 3.28 (t, J ) 7.0 Hz, 2 H),
.41 (t, J ) 7.9 Hz, 2 H), 2.07-1.95 (comp, 2 H), 1.63 (s, 3 H);
C NMR δ 174.8, 140.0, 112.5, 48.5, 46.6, 30.8, 19.8, 17.7. The
H NMR spectrum was identical to that reported in the
2
1
1
3
Ack n ow led gm en t. Financial support for this re-
search from the National Institutes of Health (GM
6503) and the National Science Foundation is grate-
1
9
literature for this compound.
4
1
-Eth yl-5-m eth yl-5,6-d ih yd r o-2-p ip er id on e (18). Iso-
lated by column chromatography on silica gel (2:1 EtOAc:
fully acknowledged.
1
hexanes) as a colorless oil. H NMR δ 6.38 (dd, J ) 9.8, 3.4
Hz, 1 H), 5.86 (dd, J ) 9.8, 1.9 Hz, 1 H), 3.58-3.32 (comp, 3
H), 3.12 (dd, J ) 12.2, 8.5 Hz, 1 H), 2.68-2.53 (m, 1 H), 1.14
Su p p or tin g In for m a tion Ava ila ble: Copies of spectra for
2a -12d and 18 (8 pages). This material is contained in
libraries on microfiche, immediately follows this article in the
microfilm version of the journal, and can be ordered from the
ACS; see any current masthead page for ordering information.
1
1
3
(
1
t, J ) 7.1 Hz, 3 H), 1.11 (d, J ) 6.9 Hz, 3 H); C NMR δ
63.9, 144.8, 124.5, 51.7, 41.3, 29.4, 17.4, 12.5; IR (film) 1672
(19) Voshchula, V. N.; Tolkunov, S. V.; Zubritskii, M. Yu.; Dulenko,
V. I. Chem. Heterocycl. Compds. 1988, 24, 1175.
J O9519219