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Molecular Recognition between Chemically Modified -Cyclodextrin and Dec-1-ene New Prospects for Biphasic Hydroformylation of Water-Insoluble Olefins.

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was distinctly different from the spectrum of 2-H". Under
preparative conditions, the photolysis of 2-H with tetranitromethane in HFP at 2 0 ' C gave after 2 h a 19% (after 4 h,
33 YO)conversion into 1,4-dimethoxy-2-nitrobenzene
(2-NO,)
as the only product; the analogous reaction in dichloromethane
gave under identical conditions a 47 YO(after 4 h, 82 O h ) conversion into 2 - N 0 2 . Since the product in the two solvents is the
same, one can only conclude that the higher efficiency of the
conversion in dichloromethane points to a trinitromethanide
ion initiated pathway, possibly leading to a transient adduct.I4]
which is eventually transformed into 2-N02.The markedly lower efficiency i n H F P would then be caused by H F P blocking this
pathway. leaving the fairly slow reaction between 2-H" and
NO, as ;I fcasible route to 2-NO2.
1.4-Dimethylnaphthalene (3). which gave no EPR signal
upon photolysis with tetranitromethane in dichloromethane at
-60 'C."''] in H F P under the same conditions but at 5 "C gave
a broad unresolved signal. A preparative run in H F P ([3] = 0.5,
[tetranitromethane] = 1.0 moldm-3) at 20°C after 40% conversion showed essentially quantitative formation of 1,4dimethyl-7-nitro-naphthalene. Again it is evident that the formation of the 3"+-trinitromethanide ion derived products
obtained i n dichloromethane at 2 0 ' C,IS1namely the adducts 4
and 5 (in total 49 YOyield) and the side chain nitro substitution
product 6 (48 '!A), have been completely suppressed.
3
4
5
6
These examples demonstrate the unique high persistency of
radical cations in HFP, which allows these radical cations to be
observed in the presence of a nucleophile such as trinitromethanide ion even at room temperature. The reactivity of the
radical cations that remain leads to dehydrodimer formation
and:or radical coupling with NO, to give the "normal" product(s) of the reactions of ArH" with NO,. Thus it appears that
HFP will discriminate decisively between the radical and electrophilic reactivity of radical cations.
German version:
-
Eric Monflier,* Georges Fremy, Yves Castanet, and
Andrk Mortreux
The development of water-soluble catalysts for the hydroformylation of olefins in a two-phase system has attracted a
great deal of attention during the last years. The application of
this concept to the hydroformylation of propylene has been
developed industrially by Hoechst AG using ;I water-soluble
rhodium catalyst containing triphenylphosphane trisulfonate as
ligand."' Although hydroformylation of long-chain olefins can
be achieved in good yields in the presence of organic solvent,
these olefins are generally hydroformylated slowly with low selectivities in two-phase systems owing to their poor solubility in
water."] To solve these problems, surfactants.l'I catalyst-binding ligands,["] amphiphilic phosphanes.I5] supported aqueousphase catalysts,['l and/or c o ~ o l v e n t s [have
~ ~ been used. However, despite these numerous efforts, the hydroformylation of
water-insoluble olefins remains a challenge, and research in this
field is still being pursued.
We have previously reported in this journal that the Wacker
oxidation of higher a-olefins could be achieved in high yields (up
to 95%) in an aqueous two-phase system in the presence of
P-cyclodextrins functionalized with hydrophilic or lipophilic
groups.'81 In this reaction, the chemically modified P-cyclodextrins behaved mainly as inverse phase-transfer catalysts. Indeed,
owing to the formation of inclusion complexes. the chemically
modified cyclodextrins can transfer the higher olefins into the
aqueous phase and so improve the mass transfer between
aqueous and organic layers. We wish now to report that these
chemically modified [j-cyclodextrins were also very effective for
the hydroformylation of water-insoluble olefins in a n aqueous
two-phase system free of organic solvent (Scheme
The typical results obtained with and without chemically
modified cyclodextrins are given in Table 1. The catalytic activ-
Received: June 8, 1995 [Z8071 I€]
C/ioir. 1995. 107. 1417- 2418
Aiipw.
Keywords: hexafluoropropanol nitro compounds
chemistry . radical cations tetranitromethane
-
Molecular Recognition between Chemically
Modified P-Cyclodextrin and Dec-1-ene :
New Prospects for Biphasic Hydroformylation
of Water-Insoluble Olefins**
-
I
11
a+b=21
photo0
[ I ] L. Ehcrwn. M . P Hartahorn, 0. Persson. ,I Cheni. Soc. C/ieni.C ~ i t i f ~1995.
i .
1131 1 1 32: .I C ' h w i . Soc. Perkin Trunc.. 3, in press.
121 a ) 1.theraun. M . P. Hartshorn, F. Radner, J 0. Svensson, J. Chein. Soc. PivAifi
7 r u i i \ 3 1994. 1719 1730: h) C P. Butts. L. Eberson. M . P. Hartshorn. 0.
Perswii. \h r. Robinson, Acru C/imi. Scond. 1995. 49. 153 -264.
131 A rim11;ir mcch;inism opei-ates in thc generation of ArH" from the photolysis
01 Art{ uith 1.3-dichloro-4.5-dicyanobenzo~~ninone
i n trilluoroacetic acid:
A. (i. D a v i c . K.-M. Ng. ,411.Tl.J C/inii. 1995. 48. 167-173.
[4j Mo\t producta from the photolysis of ArH and tetranitromethane in dichloroinethaiir o r xctonitrile are derived by elimination of nitroform or nitrous acid
from initiall~formed nitro-trinitromethyl or nitrito-trinitromethyl 1.2- and;or
I.4-adduct.. to the aromatic ring system. The persistency o f the addiicts range
from isolahlc t o transient. See earlier papers of this series and two revieNs: L.
Ehcrsoii. M . P. Hartshorn. F. Radner. Acto C % m S u m / . . 1994. 4s. 937 -950;
A i l v u i i w v i i i C'ur/~iicutfiniC'/iciiii.\rrjr RJ/2 (Ed.: J. M . Coxon). JAI, 1995. in
)?re\\
[S] L. Eherwn. M. P. Hartshorn. F. Radner, J. Cheni. So<. Perkin Truns. 3 1992.
17'J'J 1 X O f x
d
H
+
AH
O
Scheme 1. Rhodium-catalyzed hydroformylation of dec-1 - m e i n a two-phase system. The chemically modified cyclodextrins are schematicall) repesented by i~ hollow truncated cone. R = C H , , CH,CH(OH)CH,. C O C H ,
['I
Dr. E. Monflier
Universitk d'Artois. Faculte des Sciences J. Perrin
Rue Jean Souvraz. Sac postal 18. F-623(17 Lens (Fraiicc)
Telefax: Int. code + 21791717
Dip].-Chem. G. Fremy. Prof. Dr. A. Mortreux. Prof. L)r Y. Castanet
Laboratoire de Catalyse HetCrogene et Homogene
Villeneuve d'Ascq Cedex (France)
[**I
This work was supported by the CNRS.
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Table 1 . Hydroformylation of dec-I-ene i n the presence of chemically modified cyclodcxtrins [a]
No.
Cyclodextrin [h]
type
R
Conversion
'U,[cl
h
(I
(dec-1 -enc)
[mol
1
7
3
4
5
6 [fl
7
8
9
10
11
CH3
CH,
CH 1
COCH
,
COCH,
CH2CH(OH)CH
SO,Na
0
0
0
12.6
12.6
21
21
14
6.3
9
973
1297
I135
1310
1310
142x
2017
I724
1500
1'53
18
24
21
8.4
8.4
0
0
7
14.7
12
~
~
~
/?:,w-ratio
[d 1
Selectivity
(aldehyde formation)
[e][mol "A]
6
8.5
6
15
2.7
3.2
2.5
2.1
1.8
1.9
2.5
2.6
2.6
60
85
66
78
7
84
69
%I
10
~
Y-ield
[mol'%,]
10
9
19
76
100
30
6
46
32
7
69
95
17
4
26
27
5
2.8
91
95
57
66
57
~
ki] Reaction conditions: [Rh(acac)(CO),j (0.16 mmol). P(/wC,H,SO,N;i),
(0.8 mniol). cyclodextrin ( I . I 2 mmol). H,O (45 mL). dec-1-enc (80 mmol). undecane (4 mmol).
p(CO;H,) = 50 atm. T = 80 C. i = 8 11. [b] For the structures of cyclodextrins see ref. [14]. (I = no. of hydrophilic or hydrophobic groups R: h = no. of free OH groups
(Schemes 1 and 2). The cheinically moditied cyclodextrins were supplied by Cyclolah (Budapest, Hungary) and Aldrich Chemical Co. and used without further purification.
[c] Relative molecular mass of the cyclodextrin. [d] Ratio of linear ( I t ) to branched aldehyde ( i s o ) [el (Yield aldehydes);(dec-1-ene conversion); the side products were mainly
dec-2-ene. dec-3-ene. and dec-4-ene. [q Cyclodextrin (2.24 mmol): the time rcquired for complete conversion was 6 h: at the end of the reaction the phase separation was
excellent and the Rh and P content in the organic phase was <0.5 and 1.2 ppm. respectively: that is. the water-soluble catalysts ciin be easily and complctely recovered after
the reaction
ities of the classical a-, /Iand
, 7-cyclodextrins are rather disappointing.["] Actually, the only suitable cyclodextrin was the
j-cyclodextrin, and the dec-I -ene conversion can only be enhanced by a factor of 2 (entry 4). Interestingly, the functionalization of this p-cyclodextrin with hydrophilic or hydrophobic
groups such as methyl. acetyl, and 2-hydroxypropyl improved
the dec-1 -ene conversion greatly. The best results have been
obtained with the dimethyl-B-cyclodextrin (entries 5 and 6).
Indeed, in this case the dec-I -ene conversion reached 100%, and
the aldehyde was formed with 9 5 % selectivity (entry 6). However, the activity is strikingly dependent on the degree of substitution of the B-cyclodextrin. For example, the permethyl-b-cyclodextrin exhibited a much lower activity than the dimethyl-11cyclodextrin. Acetylated cyclodextrins behaved similarly (entries 8 and 9).
As it has been suggested that hydroforinylation under twophase reaction conditions with water-insoluble olefins is limited
by the rate of mass transfer,"] we think that the beneficial effect
of the chemically modified cyclodextrins on the dec-I -ene conversion can be mainly explained by an improvement of the
transfer of material between aqueous and organic layers according to Scheme 2.
The effectiveness of chemically modified cyclodextrins on the
mass transfer is probably due to the solubility of these cyclodextrins in both the aqueous and organic layers. Indeed, in contrast
to the 8-cyclodextrin and the sulfonated B-cyclodextrin, which
are totally insoluble in the organic phase, the dimethyl-/l-cyclodextrin and the diacetylated-p-cyclodextrin dissolve well in
water and partially in the organic layer, and can therefore transfer the olefin rapidly into the aqueous phase." ' ] This hypothesis
is in agreement with the results obtained with the peracetylated
and the permethylated-P-cyclodextrins. These cyclodextrins are
weakly soluble in aqueous layer and are preferably localized in
the organic layer. Consequently, transfer of dec-I-ene into the
aqueous layer is unlikely. Another possible explanation could be
the lower stability of the host-guest complexes. The stability
constant of the inclusion complex between the aldehyde and
chemically modified cyclodextrin is probably weaker than that
of the aldehyde-cyclodextrin complex (fewer hydrogen bonds).
Therefore, the organic compounds and cyclodextrins would dissociate and associate more readily (step 1 and 3 in Scheme 2).
The unusually high selectivities (up to 90%) observed with the
dimethyl-/{-cyclodextrin could be explained by the deeper hydro-
Aqueous layer
M
//
Rh / P(mC6H4S03Na)3
CO /H,
Scheme 2. TransCer of material between the aqueous and the organic phases
in the presence of chemically modified cyclodextrin during the dec-1-ene
hydroformylation.
phobic cavity in the host of this cyclodextrin, which would wrap
the olefin efficiently and would so avoid isomerization by the
rhodium catalyst." 2 1 Finally, the variations of the normal to
branched aldehyde ratio (1.8 to 3.2) could be attributed to the
ability of modified cyclodextrins to cause preorientation of the
dec-I -ene in the host cavity and/or to interactions between the
cyclodextrin and the catalyst. Indeed, interactions between transition metal complexes and cyclodextrins can give rise to the formation of inclusion compounds.['0-13] To confirm this latter hypothesis, NMR investigations are now under way in our laboratory.
These results and our previous work on the Wacker oxidation
of higher olefins support the idea that the beneficial effect of
chemically modified cyclodextrins in an aqueous two-phase system is a phenomenon of general importance. As the chemically
modified cyclodextrins are nontoxic, cheap, biodegradable, and
bulk industrial chemicals, the use of these compounds in biphasic reactions catalyzed by transition-metal complexes should
become general. Due to the chiral environment of cyclodextrins,
some fruitful developments are possible, for example, in asymetric catalysis.
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E.~ppc~rirlzl~/lro/
Proc~c.hrre
I n ii Iypical experiment, [ R h ( x a c ) ( C O (0.1 6 inmol). P(f,iciii-C,H,SO,NII),
ted
w1 ynthesized a s reported by R. Giirtner
(0.8 mino1 t h i s ~ ~ i l l i i i ~ iphosphane
et ill. [ I 51). ,ind chemically modified cyclodextrin (1.12 mmol) were ditsolvcd in
u'iter (45 1111.) .\ \t;rinless steel autoclave (100 mL) w a s charged under an xtino\phere 0 1 N1 with thc resulting q u c o u s phase and a n organc phase composcd of
dcc-I-enc (80 nrinol) ;ind undecxne (4 mmol. GC internal standard), and then hcatcd :it X O C and pressuriaxl w i t h SO atm of CO:H, ( l : l ) . A meclianical ctirrer
(1000 i p m j equipped with :I inultipaddle unit was then started. The pressure was
kept con\tant thr~rughoutthe whole reaction by uiing a gas reservoir along w ~ t ha
prc\surc regul;itoi The reaction % a s monitored by quantitative faschromatographic sn,il>\i\ (('I'SiI5-C'B. 25 in. inner diameter 0.32 mmj.
Received: June 3. 1995 [Z7X121E]
German version: An,Toi.. Cheiii. 1995. 107. 2450 2457
Keywords: cyclodextrins . hydroformylation * phase transfer
catalysis . rhodium compounds . Wacker oxidation
[I]
\I, >\. Herrmann. C. W Kohlpaintner. Angm.. C/wui. 1993. 105. 1588:
4 n y ~ i i ~<.' / I ( I U . Inr Ed. Ens/. 1993. 32. 1524. h) B. Cornila. E. Wiebus.
( ' / l t h 1 7 ' E ( / I 1995. 33: c ) Cheni. Iirg Z d i . 1994, 66. 916: d ) W. A . Herrmann.
C ' W. Kohlp;iintner. R. B Manetsherper. H. Bahrmann. H. Kottinan. .1. ,Mo/.
( ' u r n / 1995. V i . 65.
;I)
121 S S Divekai. R. M . Bhanagc. R. M. Deshpande. R. V. Gholap. R . V Chaud11<111../. , M I , / ( ~ u r u l .1994. Y I . L I .
[3] a ) M. 1 H . Russel. 8. A. Murrer (Johnson Matthey). US-A 4399312. 1983
[ < / w n i .Ah.\/, 1982. Y7. P23291nI: b) H . Bahrmann. P. Lappe (Hoechst AG).
Fur.. Pur. Appl. 602463. 1994 [Chem. A h r r . 1994. 121. P107982rl. c) T. Bartik.
H. tlai-Ilk. 8 k. Hanbon. .I Mu/. Ccod. 1994. 88, 43.
141 Ti V. ('h;iudhari. B. M Bhanage, R. M. Deshpande. H Delmas. .Vn/irr.c 1995,
373. 501
151 a ) H. Ding. H.k.Hailson. T. Bartik. B. B a t i k . O ~ ~ q f i ~ i o / i r ~ t1994.
r r / / / i13.
. ~ 3761 :
b j H. Ding. T E. Glass. B. E Hanson, Inorg. Chrm. AL./<J
1995. 229. 3289: c)
B Fcll. ( i Papadogianakis. J. Mol. Curd. 1991. 66. 143: d ) H Bahrmann. G.
I)ci.krrs. VY Grcb. P. Heyinanns. P. Lappe, T. Mueller. J. Szameitat. E. Weibus
( l i o c c h d A(;). t'iir.. Prrr. A p p / . 602442. 1994 [C%riri. A h w . 1994. 121.
P I 0797XU]
[h] I . J'. Arhmcct. M. E Davis. .I. S. Merola. B. E. Hanson, J C'ural. 1990. 121.
377
[7] 1; Montcil. K . Queau. P. Kalck. ./. Or.gaiu)i?ict.Chern. 1994. 480. 177.
[XI a ) 1. Monllier. E. Blouet. Y. Biirbaux. A. Mortreux. A i ~ ~ j i e i iC'/wn?.
..
1994. 1116.
2183: 41i,qcii, ('hrni. In/. 0 1 . Etigl. 1994, 33. 2100: h) E. Monflier. S. Tilloy. G.
Freiny. Y. ILirbnux. A. Mortreuw. Tc~trirheilronLerr. 1995, 36, 387.
[Y] t.Monllici. Y. C~isranet.A. Mortreux (Centre National d e 12 Recherchc Scientilique). t [<-A 9500466. 1995.
[lo] Thc lack ol activity of the a-cyclodestrin has also observed by W. R. Jackson
during the biplrasic hydrolormylation but with hex-I-ene; J. R. Anderson.
E. M Cainpi. W. R. Jackson. Co/o/. Lett. 1991. 9, 55.
1111 a ) 1). Ihchcne. D Wouessidjewe. J. Coorrl. Chem. 1992, 27. 223: b) H. Ikeda.
I<K o p . ( ' .I. Yoon. T.Ikeda. J In</u.\ionPhmoiri. Mu/. Kcr.og17it.Chfwi. 1989.
7. 1 I , c ) C'. M. Spencer. J. F. Stoddart. R. Zarzycki, J. C/i?iii.Soc. Perkiri 7kun.v
7 1987, 1323. d ) Y. Kubota. T. Tanimoto. S. Horiyama. K . Koiruini. Cur.ho/i~il.
K<..,. 19x9. /Y-'. 159.
[I21 M C ~ u g l e rE. Ecke. J. 1. Stezowski. J. C h i . Soc. Chcni. C'oii?muii. 1981, 1294.
1131 I f . M ('olquhoun. J. F. Stoddart. D. J. Williams. An,&yiv Chcrri. 1986. YH. 483:
Airgvii. ( ' / i w i . In!. E d Engl. 1986. 75. 487.
1141 G Wcw. 4i/,qc,11.C/WII.1994. 106. X51: An,Tcti.. C h ~ n ?Iiit.
. €d. B i g / . 1994. 33,
Facial Diastereoselectivity in the Paterno - Buchi
Reaction of Chiral Silyl Enol Ethers**
Thorsten Bach," Kai Jodicke, Kristian Kather. and
Jiirgen Hecht
The [2 + 21 photocycloaddition of alkenes t o carbonyl compounds commonly known as the Patern6 - Buchi reaction provides an efficient and straightforward route to functionalized oxetanes.['] By employing chiral auxiliaries it has become possible
to photochemically produce enantiomerically pure oxetanes.lZ1
Studies by Scharf et al. impressively demonstrated that the two
diastereotopic carbonyl faces can be well differentiated in phenyl
glyoxylates of 8-phenylmenthol and related concavc alcohol^.'^'
Besides the auxiliary-directed methodology there are several procedures that employ cyclic substrates to establish a stereoselective
carbonyl photocy~loaddition.[~~
In these cases a htcreogenic center within the ring system is responsible for it successful side
differentiation. Contrary to the auxiliary-directed method, the
chirdl information is not removed after the reaction but is utilized
for further synthetic operations. Analogously acyclic chiral substrates have not yet been employed for the preparation of enantioinerically pure oxetanes. Chiral aldehydes, which showed a
remarkable Cram selectivity in nucleophilic addition reactions,
proved less selective as carbonyl substrates in Paterno- Buchi
reactions and yielded an unsatisfactory mixture of diastereoisomers.[']
In connection with our studies on the regio- and stereoselective photocycloaddition of silyl enol ethers to aromatic aldehydes,"] we were intrigued by a possible synthesis of enantiomerically pure oxetanes according to the principles of acyclic
stereoselection. We started our investigations with a single carbony1 compound (benzaldehyde) and left the z-substituent on
the silyl enol ether unchanged.['] The only parameter varied was
the 7-substituent on the silyl enol ether. The starting materials
rac-1 were readily accessible in racemic form bq addition of the
appropriate cuprates to 2,2-dimethyl-4-hexen-3-one and subsequent silylation. Upon irradiation of these substrates in the
presence of benzaldehyde the desired oxetanes were produced as
one of four possible pairs of diastereoisomers r~ic-2/ruc-3(the
formula of only one enantiomer is shown in each case). Based
on our previous studies[hc.dlit appears likely that the relative
configuration of the three substituents within the oxetane ring is
fixed. The ratio of the two diastereoisomers found therefore reflects the facial diastereoselectivity which is induced by the stereogenic center. This ratio increases with increasing size of the substituent R and is considerably high for some examples (Table 1 ) .
$R
+
O f RH -
XO.3.
[Is] R .
Gdrtnci. B Cornils. H. Springer. P. Lappe (Ruhrchemre AG). DE-B
3215030. 19x2 [ C ~ P I Ahvrr.
I I . 1984, 101, PSS331tl
t Bu
racl
Ph
" t Bu
OTMS
'OTMS
Ph'
rac2
tBU
fac3
~
[*] Dr. T. Bach, Dipl.-Chem K. JBdicke. DipLChem K . tixther.
Dip1 -Chem. 3. Hccht'"
Orfanisch-chemisches lnstitut der Universitdt
Orlcansring 23. D-48149 Munster (Germany)
Telcfax: Int. code + (251)X3-977?
e-mail: bachtcn uni-rnuenster.de
[ ' 1 X-ray crystallography
[**I
This project was generously supported hq the Deutschc F;orschungsgemeinschaft. the Fonds der Chemirchen Industrie, the Geselljchaft zur Fiirdcrung
der Westliditchen Wilhelms-Universitit. and the Dr. O t l o Riihm-Gediichtnisstil'tung. We thank Mrs. B. Wihbeling for her help w i t h the X-ray crystallographic measurement. The continuing support of Prof. I)r. D. Hoppe is gratefully acknowleged
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water, molecular, hydroformylation, ene, recognition, new, dec, chemical, biphasic, prospects, modified, olefin, insoluble, cyclodextrin
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