Iodine as Acetylation Catalyst in the Preparation of 1,1-Diacetates from Aldehydes

Full text of DOI:10.1021/jo961741e

J . Org. Chem. 1997, 62, 1563-1564
1563
Ta ble 1a
Iod in e a s Acetyla tion Ca ta lyst in th e
P r ep a r a tion of 1,1-Dia ceta tes fr om
Ald eh yd es
(°C)/time
(h)
yield mp
(°C) (%) found/reported
entry
substrate
1
2
3
4
5
6
7
8
9
benzaldehyde
ambient/0.3
4-NO2C6H4CHO ambient/2
4-ClC6H4CHO ambient/1
95
99
92
90
86
78
90
98
80
70
45-46/44-452
125/12511
Nabajyoti Deka, Dipok J . Kalita, Ruli Borah, and
J adab C. Sarma*
80/79-8011
67/67-6810
86/84-862
55/52-5411
4-MeOC6H4CHO 0-10/0.6
cinnamaldehyde 0-10/1
Natural Products Chemistry Group,
Organic Chemistry Division, Regional Research Laboratory,
J orhat 785006, Assam, India
furfural
ambient/2.5
butyraldehyde
glutaraldehyde
crotonaldehyde
acrolein
ambient/0.5
0-10/1
0-10/0.2
0-10/0.5
63/64-655
10
Received September 10, 1996
a
All the compounds give satisfactory spectral analysis for IR,
NMR (60 MHz), and MS. Yields are all of isolated pure products,
and mp’s are uncorrected.
Aldehydes are known to react with simple anhydrides
in the presence of acid catalysts to give 1,1-diacetates
(acylals).1 Because of their stability in neutral as well
as basic media,2 the acylals are gaining importance in
synthetic organic chemistry as aldehyde protecting group
alternatives to acetals.3 The acylals of R,â-unsaturated
aldehydes are important starting materials for the
synthesis of acetoxy dienes and vinyl acetate.4 Acylals
have been applied as crosslinking reagents for cellulose
in cotton.5 One European patent claims the use of
peroxygen compounds of the 1,1,5-triacetoxy-4-pentene
type as activators in the composition of bleaching mix-
tures for wine-stained fabrics.6
Sch em e 1
H+
RCH(OAc)2
+
RCHO
Ac2O
1
3
2
Sch em e 2
OAc
OAc
OAc
OAc
Ac2 O/I2
ambient temp./30 min
+
CHO
(1)
Usually, the acylals 3 are prepared from aldehydes 1
and acetic anhydride 2 under the catalysis of strong acids
such as sulfuric acid,1 phosphoric acid, or methane-
sulfonic acid7 (Scheme 1). Olah et al.8 have reported the
use of Nafion-H as a catalyst for this conversion where
average yields of products are moderate and reaction
times are 3-5 h, except in two cases. Lewis acids like
ZnCl2,9 FeCl3,2 and PCl310 and zeolites11 of different types
are also used as catalysts for this conversion. But in most
cases, either a long reaction time (up to 120 h in the case
of 2-furyl aldehyde with PCl310) or a low yield of product
(4% in case of 4-nitro benzaldehyde10) is incurred. There-
fore, the development of new reagents with more ef-
ficiency and better yield is of interest.
OH
OH
OAc
dehyde are worth mentioning as they give quantitative
yields by this method, in contrast to yields of 4% and 30%,
respectively, with PCl3.10 The nature of the substituents
on the aromatic ring seems to have no effect on the
reaction system. In the case of aliphatic aldehydes, one
also observes high yields in short reaction time. The 25%
water solution of glutaraldehyde gives an almost quan-
titative yield of diacylal, thus indicating the versatility
of this reagent system.
Exp er im en ta l Section
While the catalytic activity of iodine in the acetylation
of alcohols with acetic anhydride was being studied,12 the
following conversion was observed (Scheme 2, eq 1) in
more than 90% yield and after a short reaction time.
To generalize the feasibility of the reaction in other
systems, we examined 10 different aldehydes (Table 1)
including aromatic and aliphatic and R,â-unsaturated
ones. In almost all cases, the reactions are quicker than
those of the reported methods and the yields are quite
high. The cases of 4-nitrobenzaldehyde and cinnamal-
Typ ica l P r oced u r e. A solution of benzaldehyde (2 mmol)
in 2 mL of chloroform is stirred at room temperature under
nitrogen atmosphere. Freshly distilled acetic anhydride (10
mmol) is added to it followed by the addition of iodine (0.2 mmol)
as catalyst. The reaction is monitored in TLC and on completion
worked up by adding water and chloroform to the reaction
mixture followed by washing with a solution of sodium thiosul-
fate. The organic layer was then washed with water and dried
over anhydrous sodium sulfate and evaporated under reduced
pressure to get the desired product in pure form. The acylal of
benzaldehyde showed identical spectral data and mp as reported
earlier.2 In an isolated example, 5.3 g (50 mmol) of benzaldehyde
gives a satisfactory result (85% isolated yield) with 5% of the
catalyst also.
Five of the compounds synthesized had spectra and mp’s
identical to those reported previously.2,5 The reactions of anisole
(Table 1, entry 4), cinnamaldehyde (Table 1, entry 5), glutaral-
dehyde, crotonaldehyde, and acrolein (Table 1, entries 8-10) are
done at 0-10 °C.
The acylals of the following aldehydes show MS (EI), NMR
(60 MHz, CDCl3), and IR (CHCl3) spectra as mentioned below.
4-Nitr oben za ld eh yd e: NMR δ 8.05 d (J ) 9 Hz, 2H), 7.47
d (J ) 9 Hz, 2H), 7.45 s (1H), 2.10 s (6H); IR 1760, 1540, 1460,
1235, 1095, 1060 cm-1; MS m/ e 253, 210, 194, 150, 134, 77.
(1) Gregory, M. J . J . Chem. Soc. B 1970, 1201.
(2) Kochhar, K. S.; Bal, B. S.; Deshpande, R. P.; Rajadhyaksha, S.
N. Pinnick, H. W. J . Org. Chem. 1983, 48, 1765.
(3) Greene, T. W. Protective Groups in Organic Synthesis, 1st ed.;
Wiley: New York, 1981; p 116.
(4) Held, H.; Rengstl, A.; Mayer, D. Ullman’s Enclycopedia of
Industrial Chemistry, 5th ed.; Gerhartz, W., Ed.; VCH: New York,
1985; Vol. A1, p 68.
(5) Frick, J . G., J r.; Harper, R. J ., J r. J . Appl. Polymer Sci. 1984,
29,1433.
(6) Eanderson, W. R. Eur. Pat. Appl. EP 125,781; Chem. Abstr. 1985,
102, P64010K..
(7) Freeman, F.; Karchevski, E. M. J . Chem. Eng. Data 1977, 22,
355.
(8) Olah, G. A.; Mehrotra, A. K. Synthesis 1982, 962.
(9) Scriabine, I. Bull. Soc. Chim. Fr. 1961, 1194.
(10) Michie, J . K.; Miller, J . A. Synthesis 1981, 824.
(11) (a) Pereira, C.; Gigante, B.; Marcclo Curto, M. J .; Carreyre, H.;
Perot, G.; Guisnet, M. Synthesis 1995, 1077. (b) Kumar, P.; Hegde, V.
R.; Kumar, T. P. Tetrahedron Lett. 1995, 36, 601.
(12) Borah, R.; Deka, N.; Sarma, J . C. J . Chem. Res., Synop. in press.
4-Ch lor oben za ld eh yd e: NMR δ 7.50 s (1H), 7.30 s (4H), 2.10
s (6H); IR 1755, 1605, 1495, 1375, 1215 cm-1; MS m/ e 244, 242,
201, 199, 185, 183, 156, 142, 141, 139, 111, 77.
4-Meth oxyben za ld eh yd e: NMR δ 7.40 s (1H), 7.35 d (J )
9Hz, 2H), 6.75 d (J ) 9Hz, 2H), 3.80 s (3H), 2.10 s (6H); IR 1763,
S0022-3263(96)01741-0 CCC: $14.00 © 1997 American Chemical Society

1564 J . Org. Chem., Vol. 62, No. 5, 1997
Additions and Corrections
1614, 1519, 1372, 1241, 1204 cm-1; MS m/ e 238, 195, 179, 152,
135, 107, 93, 92, 77, 65.
Bu tyr a ld eh yd e: NMR δ 6.50 m (1H), 2.40-2.00 brm (2H),
2.00 s (6H), 1.90-1.30 brm (2H), 1.00 t (J ) 7 Hz, 3H); IR 2960,
1765, 1374, 1244, 1208, 1010 cm-1; MS m/ e 175 (M + 1), 161,
160, 132, 116, 101, 74.
Cr oton a ld eh yd e: NMR δ 6.70 d (J ) 6 Hz, 1H), 6.00-5.10
m (2H), 2.10-1.90 (overlapping signals of 9H); IR 1760, 1390,
1250, 1215 cm-1; MS, m/e 173 (M + 1), 159, 158, 145, 141, 131,
99, 71, 69, 55.
Ack n ow led gm en t. We are grateful to the DST,
Government of India, for financial support and to the
Director, RRL, J orhat for providing necessary facilities.
One of us (D.J .K.) thanks CSIR, New Delhi, for provid-
ing a fellowship. Thanks are also due to Dr. N. C. Barua
for helpful discussions.
J O961741E
Additions and Corrections
Vol. 61, 1996
Hir oyu k i Sa im oto, Koji Yosh id a , Tetsu ya Mu r a k a m i,
Min or u Mor im oto, Hitosh i Sa sh iw a , a n d Yosh ih ir o
Ma u r izio P u lici, F u m io Su ga w a r a ,* Hir oyu k i Kosh in o,
J u n Uza w a , Sh igeo Yosh id a , Em il Lobk ovsk y, a n d
Sh igem a sa *. Effect of Calcium Reagents on Aldol Reactions of
Phenolic Enolates with Aldehydes in Alcohol.
J on Cla r d y*. Pestalotiopsins A and B: New Caryophyllenes
from an Endophytic Fungus of Taxus brevifolia.
Page 6769, footnote a in Table 2 should read as
follows: RCHO, 0.72 mmol; substrate, 0.60 mmol; sol-
vent, 2 mL; 0 °C. Solvent: MeOH except run 1 (H2O-
MeOH 2:3) and run 6 (H2O-MeOH 1:1).
Page 2122, abstract, line 4. Ratio of 5:6, not 6:5.
Page 2123, column 2. All references to major con-
former (component) should be for minor conformer (com-
ponent), and vice versa.
J O9640332
S0022-3263(96)04033-9
J O964032+
Melin d a L. Gr eer a n d Sila s C. Bla ck stock *. Complexes of
Oxygenated trans-Azoalkanes and Tetracyanoethylene. The
Interaction of π Oxygen Anions with an Electron Poor Alkene.
S0022-3263(96)04032-7
Diego A. Alon so, La r r y R. F a lvello, Ba lbin o Ma n ch en˜ o,
Ca r m en Na´jer a ,* a n d Mila gr os Tom a´s. Lithiated γ-Tosyl-
Substituted Benzylmethallylamine: New γ-Amino Methallyl
Sulfone Anions in Organic Synthesis.
Pages 7897 (Table 1) and 7902 (Tables 3 and 4). Due
to an error in calculation, the formation constants (Kf)
reported in Tables 1, 3, and 4 are incorrect. The correct
Kf values for Table 1 are (entries 1-5 sequentially) 2.8
( 0.4, 0.8 ( 0.2, 0.4 ( 0.04, 0.8 ( 0.02, and 0.6 ( 0.04
M-1. The corrected Kf values for Table 3 are 2.33 M-1 (λ
344 nm), 1.82 M-1 (λ 364 nm), 3.23 M-1 (λ 394 nm), and
4.55 M-1 (λ 410 nm) and for Table 4, 0.27 M-1 (λ 500 nm),
0.50 M-1 (λ 520 nm), 0.32 M-1 (λ 540 nm), and 0.36 M-1
(λ 550 nm).
Page 5007, Table 2. Entry 9 (see below) was omitted
from the table.
Ta ble 2. Rea ction of In ter m ed ia tes 10 w ith
Dielectr op h iles
Su p p or tin g In for m a tion Ava ila ble: Corrected Kf values
for Tables S1-S7 published with the original paper (1 page).
This material is contained in libraries on microfiche, im-
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