One-step stereoselective synthesis of dialkyl 1,1-diacetyl-8a-hydroxy-8- oxo-1,2,8,8a-tetrahydrocyclopenta[a]indene-2,3-dicarboxylates from the reaction of dialkyl 2-(1-acetyl-2-oxopropyl)-3-(tributylphosphoranylidene) succinates with indene-1,2,3-trione

Article abstract of DOI:10.1080/104265090920912

Protonation of the highly reactive 1:1 intermediates produced in the reaction between tributylphosphine and dialkyl acetylenedicarboxylates by acetylacetone leads to sterically congested phosphorus ylides that undergo an intermolecular addition reaction with indene-1,2,3-trione and concomitant intramolecular Wittig reaction in CH₂Cl₂ at room temperature to produce dialkyl 1,1-diacetyl-8a-hydroxy-8-oxo-1,2,8,8a- tetrahydrocyclopenta[a]indene-2,3-dicarboxylates in fairly good yields. Copyright Taylor & Francis Inc.

Full text of DOI:10.1080/104265090920912

Phosphorus, Sulfur, and Silicon, 180:2285–2290, 2005
Copyright © Taylor & Francis Inc.
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/104265090920912
One-Step Stereoselective Synthesis
of Dialkyl 1,1-Diacetyl-8a-hydroxy-8-oxo-1,2,8,8a-
tetrahydrocyclopenta[a]indene-2,3-dicarboxylates
from the Reaction of Dialkyl 2-(1-Acetyl-2-oxopropyl)-3-
(
tributylphosphoranylidene) Succinates with
Indene-1,2,3-trione
Ali Ramazani
Ebrahim Ahmadi
Nader Noshiranzadeh
Chemistry Department, Zanjan University, Zanjan, Iran
Protonation of the highly reactive 1:1 intermediates produced in the reaction be-
tween tributylphosphine and dialkyl acetylenedicarboxylates by acetylacetone leads
to sterically congested phosphorus ylides that undergo an intermolecular addition
reaction with indene-1,2,3-trione and concomitant intramolecular Wittig reaction
in CH Cl at room temperature to produce dialkyl 1,1-diacetyl-8a-hydroxy-8-oxo-
2
2
1
,2,8,8a-tetrahydrocyclopenta[a]indene-2,3-dicarboxylates in fairly good yields.
Keywords Acetylacetone; acetylenic esters; indene-1,2,3-trione; intramolecular Wittig
reaction; tributylphosphine
INTRODUCTION
Organophosphorus compounds have been extensively used in organic
1
,2
synthesis. A well-known method for achieving alkenylation is the
Wittig reaction.1 β-additions of nucleophiles to the vinyl group of
vinylic phosphonium salts leading to the formation of new alkyli-
denephosphoranes has attracted much attention as a very conve-
1
,2
nient and synthetically useful method in organic synthesis.
In
the past, we have established a convenient, one-pot method for
preparing stabilized phosphorus ylides utilizing in situ generation
1
of the phosphonium salts. In this article, we wish to report facial
one-pot stereoselective synthesis of dialkyl 1,1-diacetyl-8a-hydroxy-
8-oxo-1,2,8,8a-tetrahydrocyclopenta[a]indene-2,3-dicarboxylates 10 in
Received October 12, 2004; accepted October 14, 2004.
This work was supported by Zanjan University.
Address correspondence to Ali Ramazani, Zanjan University, Chemistry Department,
P.O. Box 45195-313, Zanjan, Iran. E-mail: aliramazanani@yahoo.com
2285

2
286
A. Ramazani et al.
SCHEME 1
fairly good yields by the reaction of dialkyl 2-(1-acetyl-2-oxopropyl)-
-(tributylphosphoranylidene) succinates 4 and indene-1,2,3-trione 6
Scheme 1).
3
(
RESULTS AND DISCUSSION
Reactions are known in which an α,β-unsaturated carbonyl compound
is produced from a phosphorane and a carbonyl compound such as
3
an aldehyde or ketone. Thus, compounds 10 may be regarded as the
product of an intramolecular Wittig reaction. Such addition-olefination
products may result from an initial addition of tributylphosphine 1 to
the acetylenic ester 2 and concomitant protonation of the 1:1 adduct,

One-Step Stereoselective Synthesis
2287
followed by attack of the acetylacetone anion on the vinylphospho-
4
nium cation to form phosphorane 4. Attack of the stabilized ylide 5
on the highly electron-deficient carbonyl group of indane-1,2,3-trion 6,
would lead to the stabilized ylide 9. An intramolecular Wittig reac-
tion of stabilized ylide 9 leads to dialkyl 1,1-diacetyl-8a-hydroxy-8-oxo-
1,2,8,8a-tetrahydrocyclopenta[a]indene-2,3-dicarboxylates 10 and trib-
utylphosphine oxide 11 (Scheme 1). TLC indicated that the reactions
were completed in CH2Cl2 at room temperature after 24h. We also have
used less reactive aldehydes (p-nitrobezaldehyde and ect.) and ketones
(
acetophenone and ect.) instead of indane-1,2,3-trion in this reaction,
but no products were observed even at reflux temperature (toluene as
a solvent) after 24 h. TLC indicated that the solution contained ylide
4
and the starting aldehyde or ketone. Structures 10a–c were deduced
1
13
from their elemental analysis and their UV, IR, and H and C NMR
spectra. All of these data are the same as our previous data for the
compounds 10a–c. Since compound 10 possess two stereogenic cen-
5
ters, four stereoisomers (2R and 8aR; 2S, 8aS; 2R, 8aS, and 2S, 8aR)
5
are possible. We have proved the stereochemistry of compound 10a
(
2R and 8aR and its mirror image 2S and 8aS) via single crystal X-ray
6
diffractions method (Figures 1 and 2).
In summary, we have developed a convenient, one-pot stereoselective
method for preparing dialkyl 1,1-diacetyl-8a-hydroxy-8-oxo-1,2,8,8a-
tetrahydrocyclopenta[a]indene-2,3-dicarboxylates 10 utilizing in situ
generation of phosphorane 4. Other aspects of this process are under
investigation.
EXPERIMENTAL
Melting points were measured on an Electrothermal 9100 apparatus
and are uncorrected. IR spectra were recorded on a Shimadzu IR-
1
13
4
60 spectrometer. H and C NMR spectra were measured with a
BRUKER DRX-500 AVANCE spectrometer at 500, 125, and 470.6 MHz,
respectively.
General Procedure for the Preparation of Dialkyl
1
,1-Diacetyl-8a-Hydroxy-8-oxo-1,2,8,8a-
tetrahydrocyclopenta[a]indene-2,3-dicarboxylates (10a–c)
To a magnetically stirred solution of tributylphosphine (1) (1 mmol)
and acetylacetone 3 (1 mmol) in CH2Cl2 (4 mL) was added drop-
◦
wise to a mixture of 2 (1 mmol) in CH2Cl2 (3 mL) at −10 C over
1
5 min. The mixture was allowed to warm up to room temperature and
the solvent was removed under reduced pressure. The homogeneous

2
288
A. Ramazani et al.
FIGURE 1 Molecular structure of 10a.
mixture of the dried residue (ylide 4) and powdered indane-1,2,3-
trione (6, prepared from powdered ninhydrin 8 under thermal con-
◦
ditions [4 h at 120 C] in an oven) were dissolved in dry CH2Cl2 and
stirred for 24 h. at room temperature. The solvent was removed under
reduced pressure and the viscous residue was purified by flash column

One-Step Stereoselective Synthesis
2289
FIGURE 2 Unit cell crystal structure of 10a.

2
290
A. Ramazani et al.
chromatography (silica gel and ethyl acetate-light petroleum ether).
The solvent was removed under reduced pressure and the products
◦
were obtained as white crystals (10a: mp; 180–183 C; Yield; 65%. 10b:
◦
◦
mp; 104–108 C; Yield; 63.5%. 10c: mp; 163–165 C; Yield; 70%.). The
characterization data of dialkyl 1,1-diacetyl-8a-hydroxy-8-oxo-1,2,8,8a-
tetrahydrocyclopenta[a]indene-2,3-dicarboxylates (10a–c) are given in
our previous report.5
REFERENCES
[
1] A. Ramazani, L. Yousefi, E. Ahmadi, and A. Souldozi, Phosphorus, Sulfur, and Silicon,
79, 1459 (2004) and references cited therein.
1
[
2] J. I. G. Cadogan (Ed.), Organophosphorus Reagents in Organic Synthesis, New York:
Academic Press (1979).
[
[
3] K. P. C. Vollhardt, Synthesis, 765 (1975) and references cited therein.
4] A. Ramazani and M. Mohammadi-Vala, Phosphorus, Sulphur, and Silicon, 176, 243
(
2001).
[
[
5] A. Ramazani, Phosphorus, Sulphur, and Silicon, 178, 1839 (2003).
6] A. Ramazani, Z. Kristallogr., NCS, 219, 177 (2004).