Montmorillonite clay-catalyzed cyclotrimerization and oxidation of aliphatic aldehydes

Article abstract of DOI:10.1016/j.tetlet.2009.12.009

A temperature-dependent equilibrium is observed for the cyclotrimerization of aliphatic aldehydes in the presence of Montmorillonite K10 clay, while aerobic oxidation of aliphatic aldehydes to the corresponding carboxylic acids is favored at room temperature in the presence of Montmorillonite KSF clay.

Full text of DOI:10.1016/j.tetlet.2009.12.009

Tetrahedron Letters 51 (2010) 826–827
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Tetrahedron Letters
journal homepage: www.elsevier.com/locate/tetlet
Montmorillonite clay-catalyzed cyclotrimerization and oxidation
of aliphatic aldehydes
*
Matthew R. Dintzner , Yawo A. Mondjinou, Dominic J. Pileggi
Department of Chemistry, DePaul University, 1110 West Belden Ave., Chicago, IL 60614, United States
a r t i c l e i n f o
a b s t r a c t
Article history:
A temperature-dependent equilibrium is observed for the cyclotrimerization of aliphatic aldehydes in the
presence of Montmorillonite K10 clay, while aerobic oxidation of aliphatic aldehydes to the correspond-
ing carboxylic acids is favored at room temperature in the presence of Montmorillonite KSF clay.
Ó 2009 Elsevier Ltd. All rights reserved.
Received 29 October 2009
Revised 1 December 2009
Accepted 2 December 2009
Available online 6 December 2009
Keywords:
Cyclotrimerization
Aliphatic aldehydes
Montmorillonite clay
Oxidation
Carboxylic acids
1
,3,5-Trioxanes
Green chemistry
1
. Introduction
As concern for the environment continues to shape the way
neat) we observed only minimal formation of trioxane (3).1b Thus,
we set out to optimize conditions for the cyclotrimerization reac-
tion, with propanal as a model system, by varying the following
experimental parameters: solvent, stoichiometry, temperature,
time, and type of clay. In keeping with the tenets of green chemis-
try, we were delighted to find that solvent was completely unnec-
essary for cyclotrimerization. Similarly, varying the amount of clay
(10–100% by mass relative to aldehyde) had minimal impact on the
conversion of propanal to 3. Further, the use of unactivated (‘wet’)
clay was observed to be much more effective in promoting cyclo-
trimerization than the heat-activated clay. The effects of tempera-
ture and time were investigated simultaneously, using neat, wet
chemists think about the construction of physiologically active com-
pounds, the development of synthetic methodologies that promote
greener reactions is essential. Environmentally benign clays are ide-
ally suited for the ‘greening’ of modern synthetic chemistry—they
are naturally abundant, inexpensive, nontoxic, chemically versatile,
and recyclable. We have shown that Montmorillonite K10 clay is an
effective catalyst for a variety of reactions, including the hetero-
Diels–Alder reaction of aromatic aldehydes with 2,3-dimethyl-1,3-
butadiene. Our efforts to effect the hetero-Diels–Alder reaction
of aliphatic aldehydes with 2,3-dimethyl-1,3-butadiene (1–2,
Scheme 1), however, were unsuccessful, primarily due to a compet-
ing side reaction: cyclotrimerization (1–3, Scheme 1).1b Because
1
1
b
R
1
,3,5-trioxanes (3) have been implicated in a host of practical appli-
2
3
O
O
cations, and because their synthesis in the presence of untreated
Montmorillonite clay had not been reported, we were encouraged
to further pursue this reaction. In the course of our investigation of
the clay-catalyzed cyclotrimerization of aliphatic aldehydes, we ob-
served another competing reaction: oxidation to the corresponding
carboxylic acids (1–4, Scheme 1). Herein we report our findings.
Under the conditions that were optimal for the hetero-Diels–Al-
der reaction (heat-activated Montmorillonite K10 clay, 1 h, 23 °C,
R
O
R
3
O
O
R
H
R
K10
2
1
O
R
OH
4
*
Corresponding author. Tel.: +1 773 325 4726; fax: +1 773 3257421.
E-mail address: mdintzne@depaul.edu (M.R. Dintzner).
Scheme 1. Cyclotrimerization and oxidation of aliphatic aldehydes.
0
040-4039/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2009.12.009

M. R. Dintzner et al. / Tetrahedron Letters 51 (2010) 826–827
827
clay. The relative ratio of trioxane-to-propanal (3:1a) was assessed
7–10). The Montmorillonite KSF-catalyzed air oxidation of
aliphatic aldehydes constitutes a much milder and environmen-
tally friendlier alternative to traditional methodology for the syn-
1
over a range of temperatures (À80 to 50 °C) by H NMR analysis of
the reaction mixtures at 24-h increments over the course of
6
1
0 days, specifically by comparison of the relative integration val-
thesis of aliphatic carboxylic acids.
ues for the ketal protons of 3 with the aldehydic proton of 1a.
Interestingly, the K10 clay-mediated equilibrium appeared to favor
the trioxane product at low temperature, with the highest ratio of
trioxane-to-propanal (3:1a, Table 1) observed at À20 °C after 192 h
A typical procedure for the KSF clay-catalyzed air oxidation of
aliphatic aldehydes follows. Propanal (200 mg, 3.44 mmol) was
thoroughly mixed with Montmorillonite KSF clay (200 mg) in a
scintillation vial. The mixture was allowed to stand at room tem-
(
8 days). We rationalized this temperature dependence as an en-
2 2
perature for 168 h, and then taken up in 3 mL CH Cl and the mix-
4
tropy effect. Small amounts of by products, presumably from aldol
ture filtered and washed with 3–5 mL methanol. The filtrate was
5
concentrated under vacuum to give propanoic acid (149 mg, 59%).7
condensations, were also observed at À20 °C. In a typical proce-
dure, propanal was thoroughly mixed using a metal spatula with
untreated Montmorillonite K10 clay in a glass scintillation vial.
The vial was capped and allowed to stand at specified tempera-
tures for extended periods of time. Aliquots were periodically re-
Acknowledgments
We thank DePaul University’s College of Liberal Arts & Science
for funding, and the National Science Foundation CCLI A&I program
(Grant No. DUE-0310624) for support in purchasing our Bruker
Avance 300 MHz NMR spectrometer.
moved, and the reaction mixture filtered with CDCl
an NMR tube for analysis. The ratio of trioxane-to-propanal
3:1a) was determined by comparison of the relative integration
values for the ketal protons of 3 with the aldehydic proton of 1a
Table 1).
Although interesting theoretically, we found this reversible
3
directly into
(
(
References and notes
1.
(a) Dintzner, M. R.; Mondjinou, Y. A.; Unger, B. Tetrahedron Lett. 2009, 50, 6639;
b) Dintzner, M. R.; Little, A. J.; Pacilli, M.; Pileggi, D. J.; Osner, Z. R.; Lyons, T. W.
reaction to be rather capricious in the presence of Montmorillonite
K10, minimizing its potential usefulness in synthesis. Thus, we
next investigated the use of Montmorillonite KSF clay in place of
the K10, anticipating that the smaller surface area of KSF compared
to K10 might afford better control of the cyclotrimerization reac-
tion. Remarkably, in the presence of Montmorillonite KSF we ob-
served a different reaction all together: oxidation of propanal to
propanoic acid (1a–4a, Scheme 1). Oxidation proceeded slowly at
ambient temperature or above, but was irreversible, giving near
quantitative yield of the acid in approximately 168 h (7 days).In or-
der to confirm that atmospheric oxygen was acting as the oxidizing
agent for this reaction, a control experiment was conducted at
room temperature under a nitrogen environment. Indeed, in the
absence of atmospheric oxygen, no reaction was observed after
(
Tetrahedron Lett. 2007, 48, 1577; (c) Dintzner, M. R.; Wucka, P. R.; Lyons, T. W. J.
Chem. Educ. 2006, 83, 270; (d) Dintzner, M. R.; Lyons, T. W.; Akroush, M. H.;
Wucka, P.; Rzepka, A. T. Synlett 2005, 5, 785; (e) Dintzner, M. R.; McClelland, K.
M.; Morse, K. M.; Akroush, M. H. Synlett 2004, 11, 2028; (f) Dintzner, M. R.;
Morse, K. M.; McClelland, K. M.; Coligado, D. M. Tetrahedron Lett. 2004, 45, 79.
2. (a) Withycombe, D. A.; Mookherjee, B. D.; Vock, M. H.; Vinals, J. F. US 4,093,752,
June 6, 1978.; (b) Segawa, T.; Hosokawa, H.; Yokoro, K.; Uchino, H.; Okada, K.
Oyo Yakuri 1977, 14, 391–396; (c) Ishikawa, M.; Kagawa, N.; Hagiwara, M.;
Koboshi, S. Jpn Kokai Tokkyo Koho JP 04,024,634, January 28, 1992.; (d) Ueno, Y.;
Saeki, Y.; Akiyama, T.; Fujita, M. US 4,123,525, October 31, 1978.; (e) Hon, Y.;
Lee, C. Tetrahedron 2001, 57, 6181–6188.
3.
(a) Dermer, O. C.; Jenkins, A. M. J. Org. Chem. 1959, 24, 869; (b) Kagan, J.;
Agdeppa, D. A.; Chang, A. I.; Chen, S.; Harmata, M. A.; Melnick, B.; Patel, G.;
Poorker, C.; Singh, S. P. J. Org. Chem. 1981, 46, 2916; (c) Wakasugi, T.; Tonouchi,
N.; Miyakawa, T.; Ishizuka, M.; Yamauchi, T.; Itsuno, S.; Ito, K. Chem. Lett. 1992,
171; (d) Nishiyama, K.; Oba, M. Bull. Chem. Soc. Jpn. 1987, 60, 2289; (e)
Chandrasekhar, S.; Takhi, M.; Ravindra Reddy, Y. R.; Mohapatra, S.; Rama Rao, C.
R.; Venkatram Reddy, K. V. Tetrahedron 1997, 53, 14997; (f) Peidro, L.; Le Roux,
C.; Laporterie, A.; Dubac, J. J. Organomet. Chem. 1996, 521, 397; (g) Denmark, S.
E.; Almstead, N. G. Tetrahedron 1992, 48, 5565; (h) Sato, S.; Furuta, H.; Sodesawa,
T.; Nozaki, F. J. Chem. Soc., Perkin Trans. 2 1993, 385; (i) Mori, H.; Yamazaki, T.;
Ozawa, S.; Ogino, Y. Bull. Chem. Soc. Jpn. 1993, 66, 2498; (j) Astle, M. J.; Pinns, M.
L. J. Org. Chem. 1959, 24, 56; (k) Camarena, R.; Cano, A. C.; Delgado, F.; Zuniga, N.;
Alvarez, C.; Garcia, O. Tetrahedron Lett. 1993, 34, 6857.
1
68 h. The oxidation reaction appears to be fairly general with
aliphatic aldehydes (Table 2, entries 1–6), but no reaction was ob-
served for aromatic or a,b-unsaturated systems (Table 2, entries
Table 1
Trioxane (3) formation after 192 h at various temperatures
4. Denmark et al, observed similar results with metal-based Lewis acids Denmark,
S. E.; Wilson, T.; Wilson, T. M. J. Am. Chem. Soc. 1988, 110, 984.
Entry
T (°C)
3:1aa
5
6
.
.
Blanc, P. Y.; Perret, A.; Teppa, F. Helv. Chim. Acta 1964, 47, 567.
Larock, R. C. Comprehensive Organic Transformations: A Guide to Functional Group
Preparations; VCH: New York, 1989. and references cited therein.
1
2
3
4
5
50
23
8
0.1:1
1.3:1
1.0:1
3.9:1
0.2:1
1
7
.
Analytical data for compounds 4a–4f: Proton nuclear magnetic resonance ( H)
spectra and carbon-13 (13C) spectra were recorded at 300 MHz and 75 MHz,
À20
respectively. The proton signal of residual, non-deuterated solvent (d 7.26 ppm
À80
) was used as an internal reference for 1H spectra. For C spectra,
13
for CHCl
chemical shifts are reported relative to the d 77.23 ppm resonance of CDCl
Coupling constants are reported in Hz. Infrared spectra were recorded as thin
films on a Nicolet Avatar 360 spectrometer. Propanoic acid (4a):IR (CDCl ) 2968,
3
a
Determined by 1H NMR integration.
3
.
3
À1
1
2
940, 2880, 1734, 1653, 1463, 1412, 1381, 1340, 1154, 1095, 950, 668 cm ;1 H
3
NMR (300 MHz, CDCl
3
) d 11.73 (s, 1H), 2.40 (m, 2H), 1.17 (t, J = 7.6 Hz, 3H);
C
Table 2
NMR (75 MHz, CDCl
2936, 2875, 1711, 1465, 1412, 1381, 1150, 1105, 966, 775 cm ; H NMR
3
) d 180.0, 27.2, 8.9. Butanoic acid (4b): IR (CDCl ) 2963,
3
À1
1
KSF-catalyzed oxidation reaction
(
300 MHz, CDCl1 ) d 11.70 (s, 1H), 2.35 (t, J = 7.4 Hz, 2H), 1.68 (m, 2H), 1.00 (t,
3
3
Entry Aldehyde
Carboxylic acid
%
J = 7.5 Hz, 3H); C NMR (75 MHz, CDCl
3
) d 180.0, 36.0, 18.7, 13.3.Isobutyric acid
Yield
(4c): IR 2966, 2876, 1703, 1682, 1471, 1390, 1368, 1253, 1221, 1120, 1025, 994,
À1
1
7
1
52, 739, 702, 665 cm
;
H NMR (300 MHz, CDCl
.22 (d, J = 7.0, 6H); C NMR (75 MHz, CDCl ) d 183.4, 32.8, 18.8. Pentanoic acid
) 2960, 2935, 2874, 1711, 1467, 1413, 1381, 1279, 1216, 1108,
3
) d 11.76 (s, 1H), 2.6 (m, 1H),
1
2
3
4
5
6
Propanal (1a)
Butanal (1b)
Isobutyraldehyde (1c)
Pentanal (1d)
Hexanal (1e)
Propanoic acid (4a)
Butanoic acid (4b)
Isobutyric acid (4c)
Pentanoic acid (4d)
Hexanoic acid (4e)
Cyclohexanecarboxylic acid
(4f)
59
81
58
95
90
57
13
3
(4d):IR (CDCl
3
À1
1
9
1
40, 751 cm
;
H NMR (300 MHz, CDCl
3
) d 11.77 (s, 1H), 2.36 (t, J = 7.4 Hz, 2H),
13
.62 (m, 2H), 1.37 (m, 2H), 0.9 (t, J = 7.1 Hz, 3H); C NMR (75 MHz, CDCl
) 2957, 2933, 2870,
2861, 2700, 1711, 1467, 1450, 1414, 1379, 1292, 1245, 1213, 1146, 1111,
3
) d
180.0, 34.0, 27.8, 22.6, 14.0. Hexanoic acid (4e):IR (CDCl
3
Cyclohexanecarboxaldehyde
À1
1
(1f)
934 cm
1.30 (m, 4H), 0.9 (t, J = 6.3 Hz, 3H); C NMR (75 MHz, CDCl
24.6, 22.0, 14.0. Cyclohexanecaboxylic acid (4f): IR (CDCl
;
H NMR (300 MHz, CDCl1) d 11.80 (s, 1H), 2.35 (m, 2H), 1.65 (m, 2H),
3
3
7
8
9
Benzaldehyde (1g)
2-Butenal (1h)
3-Methyl-2-butenal (1i)
Benzoic acid (4g)
2-Butenoic acid (4h)
3-Methyl-2-butenoic acid
0
0
0
3
) d 180.3, 34.0, 31.7,
3
) 2934, 2856, 1701,
À1
1
1
452, 1420, 1312, 1256, 1213, 1182, 1136, 922, 895 cm
;
H NMR (300 MHz,
CDCl
3
) d 11.81 (s, 1H), 2.35 (m, 1H), 1.92 (m, 1H), 1.76 (m, 1H), 1.65 (m, 1H), 1.46
(
4i)
13
(
3
m,1H), 1.3 (m, 1H), 1.2 (m, 1H); C NMR (75 MHz, CDCl ) d 182.3, 43.0, 28.8,
1
0
Cinnamaldehyde (1j)
Cinnamic acid (4j)
0
25.7, 25.45.