A new and mild heterogeneous catalytic decomposition of α-diazo carbonyl compounds using montmorillonite or zeolite

Article abstract of DOI:10.1055/s-2002-20452

A very mild method of decomposition of various α-diazo carbonyl compounds 1 in the presence of environmentally attractive solid acids such as montmorillonite K-10 or zeolite H-Y in a heterogeneous manner to furnish α-hydroxy/alkoxy ketones in very good yield is reported. Interestingly, novel bicycloalkane-1,3-diones and 3-furanones were obtained as unusual products in the case of aliphatic/alicyclic α-diazo carbonyl compounds.

Full text of DOI:10.1055/s-2002-20452

LETTER
407
A New and Mild Heterogeneous Catalytic Decomposition of -Diazo Carbonyl
Compounds Using Montmorillonite or Zeolite
H
S
eterogeneou
eC atalytic
n
ecompositi
g
on of
-
Diaz
o
C
d
ompounds agounder Muthusamy,* Srinivasarao Arulananda Babu, Chidambaram Gunanathan, Raksh Vir Jasra
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 11 December 2001
composition, we herein report the mild heterogeneous cat-
alytic decomposition of -diazo carbonyl compounds
with montmorillonite clay K-10 or zeolite H-Y as applied
Abstract: A very mild method of decomposition of various -diazo
carbonyl compounds 1 in the presence of environmentally attractive
solid acids such as montmorillonite K-10 or zeolite H-Y in a heter-
ogeneous manner to furnish -hydroxy/alkoxy ketones in very good to the synthesis of -hydroxy/alkoxy ketones, bicycloal-
yield is reported. Interestingly, novel bicycloalkane-1,3-diones and kane-1,3-diones, 3-furanone ring systems.
3
-furanones were obtained as unusual products in the case of ali-
To the best of our knowledge, there is no report, which
deals with the reaction of -diazo carbonyl compounds
with solid acids such as clays or zeolites. Montmorillonite
phatic/alicyclic -diazo carbonyl compounds.
Key words: diazo ketones, heterogeneous catalysts, hydroxy ke-
tones, O-H insertion, montmorillonite, zeolite
clay K-108 and zeolites
–12
13,14
have many applications in
modern organic synthesis such as catalysts for Michael
addition reactions, Friedel–Crafts reactions, methoxyme-
thylation of alcohols and deprotection of acetal/silyl
groups.
The ready availability, relative stability and facile decom-
position, under thermal, photochemical, acid, base and
transition-metal catalyzed conditions of -diazo carbonyl
compounds make them useful intermediates in organic
synthesis. The utility of -diazo carbonyl compounds in
modern organic synthesis and their participation in a vari-
ety of transformations such as ylide formation, cyclopro-
panation and insertion reactions is well documented.1,2
The formation of inter- and intramolecular ether linkages
from diazo ketones and alcohols in the presence of rhodi-
montmorillonite K-10
or zeolite H-Y
R
COCHN2
R
COCH2OH
r.t. / DCM
1
2
Scheme 1
-
Diazo ketones 1, 3 and 5–7 involved in this work were
3
um(II) acetate is well studied. The decomposition of -
1
,16
prepared according to literature precedents. To a solu-
tion of -diazo ketone 1a (100 mg) in 4 mL of commercial
grade dichloromethane was added montmorillonite clay
K-10 (175 mg) and decomposition started with slow evol-
ution of nitrogen gas. The reaction mixture was allowed to
stir at room temperature for 5 hours and followed by TLC
until the disappearance of starting material. The reaction
mixture was filtered, concentrated under reduced pressure
and the crude reaction mixture was purified using silica
gel column chromatography to furnish -hydroxy
diazo carbonyl compounds dominantly with protic/aprotic
and Lewis acids has been well studied and also applied2
1,4
to the synthesis of important natural products. The use of
5
–7
solid acidic catalysts such as ion-exchange resins,
clays and zeolites
8
–12
13,14
has received substantial attention
in different areas of organic synthesis because of their en-
vironmental compatibility, greater selectivity, experimen-
tal simplicity, low cost, high efficiency and ease of
isolation of the products. In particular, clay and zeolite
catalysts make reaction processes expedient; cost effec-
tive, environmentally benign, and act as both Brønsted
and Lewis acids in their natural or ion-exchanged forms,
enabling them to function as efficient catalysts for various
organic transformations. Very recently, we have
15
ketone 2a in 90% yield (Scheme 1).
This reaction stimulated us to study further the decompo-
sition of other -diazo ketones 1b–h with montmorillonite
to afford the corresponding -hydroxy ketones 2b–h in
very good yield (Table 1). We have studied this reaction
with both aromatic/aliphatic diazo compounds 1 which af-
forded the respective -hydroxy ketones 2 as a result of O-
1
5
reported that a solid ionic matrix (such as Amberlyst-
®
1
5 ) mediated decomposition of -diazo ketones to afford
hydroxy ketones. Albeit reactions of -diazo carbonyl
-
3
H insertion. It is significant that -hydroxy ketones are
compounds in classic/Lewis acidic medium have been
studied, such procedures require careful handling and an
1
8
very useful intermediates in organic synthesis and their
chemistry is being exploited intensively in asymmetric
Aldol reactions.19 In some representative cases we have
carried out the decomposition of diazo ketones 1a,b in the
presence of clay K-10 under ultrasonication to furnish
products 2a,b in 1.5 hours and 2.5 hours, respectively.
4
aqueous work-up.
In continuation of our interest in -diazo ketones15–17 and
the discovery of new and effective catalysts for their de-
Synlett 2002, No. 3, 04 03 2002. Article Identifier:
Similarly, we carried out the reaction of -diazo ketones
1a–h in commercial dichloromethane in the presence of
1
©
437-2096,E;2002,0,03,0407,0410,ftx,en;D18501ST.pdf.
Georg Thieme Verlag Stuttgart · New York
ISSN 0936-5214

4
08
S. Muthusamy et al.
LETTER
zeolite H-Y as described above. The decomposition of - lective manner (Scheme 2). The reaction was repeated
diazo ketones 1a–h takes place to afford the correspond- with zeolite H-Y and also afforded product 4a. Under sim-
ing -hydroxy ketones 2a–h (Scheme 1). It may be noted ilar conditions, the product 4b was obtained from 3b using
that the yield of -hydroxy ketones in both montmorillo- clay K-10 as well as zeolite H-Y.
nite clay K-10 as well as zeolite H-Y mediated reactions
of -diazo ketones were found to be the same (see
Table 1).
We further extended the solid acid mediated reactions of
-
diazo compounds 5–7. In the case of 5, purification on
neutral alumina column afforded the novel 3-furanone de-
rivative 8 in 85% yield (Table 2). The presence of charac-
teristic singlet at = 2.72 ppm for OH proton and two
O
O
O
R3
montmorillonite K-10
or zeolite H-Y
R3
doublets at = 4.14 and 4.06 ppm having coupling con-
COCHN2 DCM, room temp.
1
stant J = 16.6 Hz for the OCH protons in H NMR spec-
2
3
2
3
3
3
3
a; R = H
4a; R = H
trum; the presence of three sp carbons, one sp carbon,
three quaternary carbons in C/DEPT-135 analyses re-
3
4b; R3 = Me
13
b; R = Me
vealed the structure of 8. Moreover, FT-IR spectrum and
the deutrium exchange experiment in NMR confirmed the
presence of hydroxy group in 8. A plausible mechanism
for the formation of isomeric furanone skeleton 8 instead
of the corresponding alcohol 8a from 5 involves intramo-
lecular cyclization of the initially formed O-H insertion
product 8a (Scheme 3). It is noteworthy that the formation
of furan ring has also been observed from -keto alcohols
Scheme 2
We have shown that diazo compounds 3a,b having a
three-carbon chain tethered to a cyclohexanone ring sys-
1
5
20
tem, react with Amberlyst-15 or Lewis acid to furnish
the rearranged 1,3-diones 4a,b instead of the correspond-
ing -hydroxy ketones. We were keen to study the effect
of montmorillonite K-10 or zeolite H-Y with diazo ke-
tones 3a,b. To a solution of diazo ketone 3a (100 mg) in
dichloromethane was added montmorillonite K-10 (125
mg) and the reaction was followed by TLC until the dis-
appearance of starting material. Filtration, followed by
concentration of the filtrate under reduced pressure, gave
a residue which was subjected to silica gel column chro-
21
of type 8a. Diazo ketones 6,7 under similar reaction con-
ditions afforded the corresponding furanones 9, 10 in very
good yield. The same results were observed using zeolite
H-Y instead of clay K-10.
Finally, we were eager to study the O-H insertion reac-
tions of -diazo carbonyl compounds 1a,b with alcohols
in the presence of clay or zeolite to obtain -alkoxy ke-
tones 11. Thus, diazo ketone 1a (50 mg) in absolute meth-
1
5,20
matography to afford product
4a (68%) in a regiose-
Table 1
-Hydroxy Ketones Produced via Scheme 1
a
b
b
-
Diazo Ketones 1
-Hydroxy Ketones 2
Time (h) r.t.
Clay Method Yield (%) Zeolite Method Yield (%)
5
9
4
3
/4
/8
/4
.5/4
2a; 90
2b; 80
2c; 83
2d; 86
2a; 92
2b; 84
2c; 87
2d; 86
1
1
1
1
1
1
a; n = 0, R = H
2a; n = 0, R = H
1
1
b; n = 0, R = OMe
2b; n = 0, R = OMe
1
1
c; n = 1, R = H
2c; n = 1, R = H
1
1
d; n = 2, R = H
2d; n = 2, R = H
6
7
/5
/5
82
79
85
82
1
1
e
f
2e
2f
3
4
/2.5
/2.5
2g; 73
2h; 76
2g; 79
2h; 82
1
1
g; n = 1
h; n = 2
2g; n = 1
2h; n = 2
a
The reaction time for clay/zeolite method.
Yields (unoptimized) refer to chromatographically isolated and pure compounds 2.
b
Synlett 2002, No. 3, 407–410 ISSN 0936-5214 © Thieme Stuttgart · New York

LETTER
Heterogeneous Catalytic Decomposition of -Diazo Carbonyl Compounds
409
COCHN2
COCH2OR2
clay K-10 or
zeolite H-Y
Methanol or
Ethanol or
Propanol
R1
R1
1
1
2
Scheme 3
1a; R = H
1
11a; R = H; R = Me (87/81%)
1
1
2
b; R = OMe
11b; R = H; R = Et (72/77%)
1
2
1
1c; R = H; R = Pr (67/61%)
1
2
1
1d; R = OMe; R = Me (71/79%)
Table 2 3-Furanones prepared by the Decomposition of -Diazo
Ketones in the Presence of Montmorillonite Clay K-10 or Zeolite H-Y
11e; R1 = OMe; R2 = Et (77/82%)
11f; R1 = OMe; R2 = Pr (70/62%)
-
Diazo Ketones 3-Furanones
Reaction Montmoril- Zeolite
Scheme 4
Timea
min)
lonite Clay
Method
Method
Yield
b
(
b
Yield (%)
(%)
Acknowledgement
1
5/12
0/15
85
72
89
This research was supported by the Young Scientist Scheme, CSIR,
New Delhi. We thank Dr. P. K. Ghosh, Director, for his encourage-
ment of this work. S. A. B. and C. G. thank CSIR, New Delhi, for a
Fellowship.
5
6
8
9
2
81
89
References
(
1) Doyle, M. P.; McKervey, M. A.; Ye, T. Modern Catalytic
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7
1
0
(2) (a) Padwa, A. Top. Curr. Chem. 1997, 189, 121. (b) Padwa,
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a
The reaction time for clay/zeolite method.
Yields (unoptimized) refer to chromatographically isolated and pure
b
compounds.
(
3) (a) Miller, D. J.; Moody, C. J. Tetrahedron 1995, 51, 10811.
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(
anol in the presence of clay (100 mg) afforded -methoxy
ketone 11a (87%). The use of zeolite H-Y under similar
experimental conditions produced compound 11a in 81%
yield (Scheme 4). We have performed the above reaction
of compounds 1a,b using clay in absolute ethanol and pro-
panol to furnish products 11b–f. A similar trend was ob-
served using zeolite H-Y in the above reactions. All new
compounds gave satisfactory spectral data consistent with
(
Trans. 1 1997, 457.
(
4) Regitz, M.; Mass, G. Diazo Compounds-Properties and
Synthesis; Academic Press: New York, 1986, 90.
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(
(6) Perni, R. B. Synth. Commun. 1989, 19, 2383.
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(
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2
2
their structures.
1
Yields of products in all reactions were comparable
whether the reaction was carried out using clay or zeolite.
There is no formation of other products due to C-H inser-
tion. Significantly in all these reactions the use of the solid
acid catalysts clay or zeolite produced high yield of prod-
ucts involving filtration of catalyst without any aqueous
work-up.
Org. Chem. 1996, 61, 3209.
(8) (a) Balogh, M.; Laszlo, P. Organic Chemistry using Clay;
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(
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(
(
(
10) Upadhya, T. T.; Daniel, T.; Sudalai, A.; Ravindranathan, T.;
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In summary, we have discovered and explored that the de-
composition of various -diazo carbonyl compounds us-
ing new and environmentally acceptable solid acid
catalysts such as montmorilonite K-10 or zeolite H-Y un-
der mild heterogeneous conditions furnished -hydroxy/
alkoxy ketones, bicycloalkane-1,3-diones and 3-fura-
nones. This solid acid method is in particularly attractive
since it does not need any aqueous work up; mere filtra-
tion of the catalyst offering high yields of product.
(13) Sreekumar, R.; Rugmini, P.; Padmakumar, R. Tetrahedron
Lett. 1997, 38, 6557; and references cited therein.
(
14) Van Herwijnen, H. W. G.; Brinker, U. H. J. Org. Chem.
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2
(
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Tetrahedron Lett. 2001, 42, 5113.
Synlett 2002, No. 3, 407–410 ISSN 0936-5214 © Thieme Stuttgart · New York

4
10
S. Muthusamy et al.
LETTER
by TLC until disappearance of starting material. The
(
(
16) Muthusamy, S.; Babu, S. A.; Gunanathan, C.; Suresh, E.;
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reaction mixture was then filtered, concentrated under
reduced pressure and purified by silica gel column
chromatography to afford product 2a. All novel compounds
gave satisfactory spectral data consistent with their
structures. Selected spectral data of 5-Hydroxy-4,4,5-
trimethyldihydrofuran-3-one (8): colourless solid, mp 63–
65 ºC; IR (KBr): 3372, 2998, 2978, 2913, 2934, 1744, 1704,
5
23. (c) Muthusamy, S.; Babu, S. A.; Gunanathan, C.;
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–
1 1
1471, 1453, 1396, 1121, 1039, 932, 851 cm ; H NMR (200
(
(
18) Whitsell, J. K.; Buchanan, C. M. J. Org. Chem. 1986, 51,
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2
5
443.
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2
1
3
CH ), 1.09 (s, 3 H, CH ), 1.05 (s, 3 H, CH ); C NMR (50.3
3
3
3
2
MHz, CDCl3): = 16.5 (CH ), 22.0 (CH ), 22.3 (CH ), 51.1
3 3 3
Shabat, D.; Anderson, J.; Gramatikova, S.; Lerner, R. A.;
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22) Typical Experimental Procedure: The clay/zeolite
catalysts used in this work were activated at 200 °C for 3 h.
To a solution containing -diazo ketone 1a (100 mg) in
commercial grade dichloromethane was added zeolite H-Y
(quat-C), 67.9 (OCH ), 107.4 (quat-C), 218.6 (C=O); MS:
2
+
m/z = 144 [M ]; Anal. Calcd for C H O : C, 58.31; H, 8.39.
7
12
3
(
(
(
Found: C, 58.40; H, 8.44. 2-Methoxy-1-(4-
methoxyphenyl)ethanone (11d): colourless thick liquid;
IR(neat): 3059, 2934, 2842, 1776, 1691, 1602, 1576, 1512,
–
1 1
1462, 1422, 1312, 1259, 1175, 1128, 1026 cm ; H NMR
(200 MHz, CDCl3): = 7.93 (d, 2 H, J = 8.6 Hz, Arom-H),
6.93 (d, 2 H, J = 8.6 Hz, Arom-H), 4.65 (s, 2 H, OCH ), 3.87
2
1
3
(s, 3 H, OCH ), 3.50 (s, 3 H, OCH ); C NMR (50.3 MHz,
3
3
CDCl ): = 55.9 (OCH ), 59.8 (OCH ), 75.5 (OCH ), 114.0
3
3
3
2
(
175 mg) or montmorillonite clay K-10 (175 mg) and the
(=CH), 130.6 (=CH), 133.2 (quat-C), 164.2 (quat-C), 195.1
+
mixture stirred at r.t. or ultrasonicated. Slow nitrogen
(C=O); MS: m/z = 180 [M ]; Anal. Calcd for C H O : C,
1
0
12
3
evolution took place and the reaction mixture was followed
66.65; H, 6.71. Found: C, 66.72; H, 6.65.
Synlett 2002, No. 3, 407–410 ISSN 0936-5214 © Thieme Stuttgart · New York