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Catalytic properties of iron and manganese glycoconjugated porphyrins.
Tetr~aedron Letters, Vol.32, No.37, pp 4901-4904, 1991 Printed in Great Britain
0040-4039/91 $3.00 + .00 Pergamon Press plc
Catalytic Properties of Iron and Manganese Glycoconjugated
Porphyrins.
Ph.Maillard, J.L.Guerquin-Kern and M.Momenteau*. lnstitut Curie, Section de Biologie, Laboratoire Associ6 au CNRS et Unit6 INSERM, B'~t 112, Centre Universitaire, 91405 Orsay, France.
Abstract: The catalytic properties of new family of tetrapyrrolic macrocycles containing some glycosylated groups are described. Of particular interest is the structure of the catalysts. Model catalytic systems involving metalloporphyrins and different oxidizing reagents have been investigated to mimic cytochrome P450 dependent oxidations 1. Of particular interest are metalloporphyrins which are both oxidatively robust and able to show a regioselectivity in alkene oxidation2, 3 Recently, we described the synthesis and characterization of glycosylated porphyrins4 1, 2 and 3 which contain chiral acetylated glucose superstructure. These groups are covalently linked to the ortho position of meso phenyl groups of tetraphenylporphyrin.
R--O~ R=
l
0tl3c~~
2
c~otct[~ M = Ha, MnCI
~
O-Ac
(YAc
M = tl2, MnCI, FeCI
3
4901
M = H2, MnCI
4902
We now report the catalytic properties of metallic complexes [chloro iron(HI) derivative, I-FeC1, chloro manganese(III) derivatives, 1-MnC1, 2-MnC1 and 3-MnC1] of these porphyrins in the asymmetric epoxidation
ofpara-chlorostyrene (Figue 1). The activity of the tetraglycosylated derivatives 1 and 2 is compared with those of the monoglycosylated compound 3-MnCI and two chiral metalloporphyrins 4 and 5 described in the literatureZ 3.
FeCI or MnC1 Glycoconjugated ~
#
'
~
H
/
H
porphyrin
CI
I1~
CI
lodosobenzene
0 H
Figure 1
The metallic complexes were prepared either by a classical method 5 for compound 3-MnC1 which is not sensitive to atropoisomerisation, or following Guilleux' method 6 for compounds I and 2 which are sensitive to isomerisation. The manganese and iron complexes 1-FeC1, 1-MnC1 and 2-MnC1 were synthetized at reflux in THF containing FeC12 or MnC13 in the presence of p-nitrophenol, under argon 7. The absorption spectra of these compounds are characteristic of iron(Ill) and manganese(III) porphyrinic derivatives8 In a typical oxidation reaction, 8x10 -4 mole
ofpara-chlorostyrene was reacted with 10 -4 mole of
iodosobenzene in purified methylene chloride9 (0.9 ml) in the presence of 2 mg of catalyst for 3 hours, at 0°C, under argon and in the dark. The para-chlorostyrene epoxide was isolated under argon by preparative column chromatography and its enantiomeric excess (e e %) was determined by 1H NMR with the use of the chiral shift reagent, tris[3-(heptafluoropropylhydroxymethylene)-(+)-camphorato]-europium(III) 2. Results are shown in Table 1 and are compared with those obtained using two chiral porphyrins (Groves' catalyst24 and Mansuy's catalyst35). Chloro iron(III) and chloro manganese(Ill) complexes of 1 were the more active catalysts with turnover numbers of 57 and 50 respectively observed after 3 hours resulting in the formation of epoxide I°. The yield of epoxidation obtained with the best glycoconjugated catalyst (1-FeCI) compares well with the results presented in the literatureZ 3. All the epoxidations show a asymmetric induction under the conditions of the experiments but lower than with other methods reportedZ3.
4903
Compound
Yield %/
e. e.a %
Turnoverb
References
IO-C6H5 1-Feel
60
33
57
this work
1-MnCI
53
27.5
50
this work
2-MnCI
34
23.5
32
this work
3-MnCI
26
0
24
this work
4*
63
51
nd
2
5 **
28
50
nd
3
Table 1: Catalytic activity of manganese and iron complexes in the oxydation ofpara-chlorostyrene in presence of iodosylbenzene, a eniantomeric excess, b Number of molecules of para-chlorostyrene oxided by one molecule of catalyst during three hours, * C1 Fe-T(~,13,~,l]-Binapht)PP 2, ** C1 Mn-[(+)phenylalanine"basket-handle"] porphyrin3. The conversion ofpara-chlorostyrene to para-chlorostyrene epoxide decreased as the microenvironment created by the sugar substitution becomes asymmetrical. Compound 2-MnC1 which is very strongly sterically hindered on one face while the second face bears only one sugar, is less active than compound 1-MnC1. In contrast, compound 3-MnC1 shows a moderate catalytic activity but without asymmetric induction, because the epoxidation reaction probably takes place on the nonchiral free face. Another interesting observation is that styrene epoxide is produced with compound I (from Fe(III) and Mn(III) complexes) in the presence of excess oxidant without oxidation of the porphyrin. This result is obtained from the visible absorption spectrum of the metalloporphyrin I-MnC1 which appears without changes after reaction. These data on the control of asymmetric induction show the importance of the sugar in the vicinity of the metal center, which induces a very large prochiral steric hindrance. The steric protection of the both faces of metalloporphyrins enhances the stabilisation of the active oxo species toward a self oxidation of the macrocycle. However it leads to decrease the catalytic activity of compounds compared with that observed using less hindered porphyrin for which rapid decomposition of the catalyst is observed lb.
Acknowledgments
Authors wish to thank CNRS (URA 1387) and INSERM (U 219) for technical and financial support. They are also extremely grateful to Dr A. Loupy and Mr A. Petit (Universit6 Paris Sud) for chromatographic analysis.
4904
References and Notes 1.
a) McMurry T.J.; Groves J.T., in Cytochrome P-450, Structure, Mechanism and Biochemistry (Ortiz de Montellano, P.R., Ed), Plenum Press, New York, pl-29, 986; b) Mansuy D.; Battioni P.; Battioni J.P., Eur. J. Biochem. 1989, 184,267. and references cited in this paper.
2
Groves J.T.; Myers R.S., J. Amer. Chem. Soc. 1983, 105, 5791.
3
Mansuy D.; Battioni P.; Renaud J.P.; Gu6rin P., J. Chem. Soc. Chem. Cornmun. 1985, 155. Maillard Ph.; Guerquin-Kem J.L.; Momenteau M.; Gaspard S., J. Amer. Chem. Soc. 1989, 111, 9125.
5
Alder A.D.; Longo F.R.; Kampas F.; Kim J.J., J. lnorg. Nucl. Chem. 1970, 32, 2443.
6
Guilleux L.; Krausz P.; Nadjo L.; Uzan R., J. Chem. Soc. Perla'n Trans II 1985, 951. Yield of metallation of free base porphyrins; 1-FeC1 52%, 1-MnCI 15%, 2-MnCI 26%, 3-MnCI 91%. U.V.-visib[¢,. spectra of metallic complexes in chloroform: )-max nmj,..(~m3.mole-l.cm-1): 1-FeCl: 420 (124,000), 570 (136,00), 576 (5,400), 651.5 (3,500) and 673.5 (3,500); 1-MnCl: 377 (46,000), 400 (45,000), 469.5 (82,000), 517 (shoulder), 556.5 (11,600), 594 (shoulder) and 618 (shoulder); 2-MnCI: 377 (49,000), 400 (48,000), 472 (92,000), 521 (shoulder), 568 (12,400) and 618 (shoulder); 3-MnCI: 376 (46,000), 402 (39,000), 478 (100,000), 527 (shoulder), 582 (9,600) and 616 (9,200)
9
Methylene chloride was distilled over calcium hydride and kept on 4/~ molecular sieves.
10
The concentration ofpara-chlorostyrene epoxide was determined by gas chromatography on a OVl-15 m capillary column.
(Received in France 31 May 1991)
0040-4039/91 $3.00 + .00 Pergamon Press plc
Catalytic Properties of Iron and Manganese Glycoconjugated
Porphyrins.
Ph.Maillard, J.L.Guerquin-Kern and M.Momenteau*. lnstitut Curie, Section de Biologie, Laboratoire Associ6 au CNRS et Unit6 INSERM, B'~t 112, Centre Universitaire, 91405 Orsay, France.
Abstract: The catalytic properties of new family of tetrapyrrolic macrocycles containing some glycosylated groups are described. Of particular interest is the structure of the catalysts. Model catalytic systems involving metalloporphyrins and different oxidizing reagents have been investigated to mimic cytochrome P450 dependent oxidations 1. Of particular interest are metalloporphyrins which are both oxidatively robust and able to show a regioselectivity in alkene oxidation2, 3 Recently, we described the synthesis and characterization of glycosylated porphyrins4 1, 2 and 3 which contain chiral acetylated glucose superstructure. These groups are covalently linked to the ortho position of meso phenyl groups of tetraphenylporphyrin.
R--O~ R=
l
0tl3c~~
2
c~otct[~ M = Ha, MnCI
~
O-Ac
(YAc
M = tl2, MnCI, FeCI
3
4901
M = H2, MnCI
4902
We now report the catalytic properties of metallic complexes [chloro iron(HI) derivative, I-FeC1, chloro manganese(III) derivatives, 1-MnC1, 2-MnC1 and 3-MnC1] of these porphyrins in the asymmetric epoxidation
ofpara-chlorostyrene (Figue 1). The activity of the tetraglycosylated derivatives 1 and 2 is compared with those of the monoglycosylated compound 3-MnCI and two chiral metalloporphyrins 4 and 5 described in the literatureZ 3.
FeCI or MnC1 Glycoconjugated ~
#
'
~
H
/
H
porphyrin
CI
I1~
CI
lodosobenzene
0 H
Figure 1
The metallic complexes were prepared either by a classical method 5 for compound 3-MnC1 which is not sensitive to atropoisomerisation, or following Guilleux' method 6 for compounds I and 2 which are sensitive to isomerisation. The manganese and iron complexes 1-FeC1, 1-MnC1 and 2-MnC1 were synthetized at reflux in THF containing FeC12 or MnC13 in the presence of p-nitrophenol, under argon 7. The absorption spectra of these compounds are characteristic of iron(Ill) and manganese(III) porphyrinic derivatives8 In a typical oxidation reaction, 8x10 -4 mole
ofpara-chlorostyrene was reacted with 10 -4 mole of
iodosobenzene in purified methylene chloride9 (0.9 ml) in the presence of 2 mg of catalyst for 3 hours, at 0°C, under argon and in the dark. The para-chlorostyrene epoxide was isolated under argon by preparative column chromatography and its enantiomeric excess (e e %) was determined by 1H NMR with the use of the chiral shift reagent, tris[3-(heptafluoropropylhydroxymethylene)-(+)-camphorato]-europium(III) 2. Results are shown in Table 1 and are compared with those obtained using two chiral porphyrins (Groves' catalyst24 and Mansuy's catalyst35). Chloro iron(III) and chloro manganese(Ill) complexes of 1 were the more active catalysts with turnover numbers of 57 and 50 respectively observed after 3 hours resulting in the formation of epoxide I°. The yield of epoxidation obtained with the best glycoconjugated catalyst (1-FeCI) compares well with the results presented in the literatureZ 3. All the epoxidations show a asymmetric induction under the conditions of the experiments but lower than with other methods reportedZ3.
4903
Compound
Yield %/
e. e.a %
Turnoverb
References
IO-C6H5 1-Feel
60
33
57
this work
1-MnCI
53
27.5
50
this work
2-MnCI
34
23.5
32
this work
3-MnCI
26
0
24
this work
4*
63
51
nd
2
5 **
28
50
nd
3
Table 1: Catalytic activity of manganese and iron complexes in the oxydation ofpara-chlorostyrene in presence of iodosylbenzene, a eniantomeric excess, b Number of molecules of para-chlorostyrene oxided by one molecule of catalyst during three hours, * C1 Fe-T(~,13,~,l]-Binapht)PP 2, ** C1 Mn-[(+)phenylalanine"basket-handle"] porphyrin3. The conversion ofpara-chlorostyrene to para-chlorostyrene epoxide decreased as the microenvironment created by the sugar substitution becomes asymmetrical. Compound 2-MnC1 which is very strongly sterically hindered on one face while the second face bears only one sugar, is less active than compound 1-MnC1. In contrast, compound 3-MnC1 shows a moderate catalytic activity but without asymmetric induction, because the epoxidation reaction probably takes place on the nonchiral free face. Another interesting observation is that styrene epoxide is produced with compound I (from Fe(III) and Mn(III) complexes) in the presence of excess oxidant without oxidation of the porphyrin. This result is obtained from the visible absorption spectrum of the metalloporphyrin I-MnC1 which appears without changes after reaction. These data on the control of asymmetric induction show the importance of the sugar in the vicinity of the metal center, which induces a very large prochiral steric hindrance. The steric protection of the both faces of metalloporphyrins enhances the stabilisation of the active oxo species toward a self oxidation of the macrocycle. However it leads to decrease the catalytic activity of compounds compared with that observed using less hindered porphyrin for which rapid decomposition of the catalyst is observed lb.
Acknowledgments
Authors wish to thank CNRS (URA 1387) and INSERM (U 219) for technical and financial support. They are also extremely grateful to Dr A. Loupy and Mr A. Petit (Universit6 Paris Sud) for chromatographic analysis.
4904
References and Notes 1.
a) McMurry T.J.; Groves J.T., in Cytochrome P-450, Structure, Mechanism and Biochemistry (Ortiz de Montellano, P.R., Ed), Plenum Press, New York, pl-29, 986; b) Mansuy D.; Battioni P.; Battioni J.P., Eur. J. Biochem. 1989, 184,267. and references cited in this paper.
2
Groves J.T.; Myers R.S., J. Amer. Chem. Soc. 1983, 105, 5791.
3
Mansuy D.; Battioni P.; Renaud J.P.; Gu6rin P., J. Chem. Soc. Chem. Cornmun. 1985, 155. Maillard Ph.; Guerquin-Kem J.L.; Momenteau M.; Gaspard S., J. Amer. Chem. Soc. 1989, 111, 9125.
5
Alder A.D.; Longo F.R.; Kampas F.; Kim J.J., J. lnorg. Nucl. Chem. 1970, 32, 2443.
6
Guilleux L.; Krausz P.; Nadjo L.; Uzan R., J. Chem. Soc. Perla'n Trans II 1985, 951. Yield of metallation of free base porphyrins; 1-FeC1 52%, 1-MnCI 15%, 2-MnCI 26%, 3-MnCI 91%. U.V.-visib[¢,. spectra of metallic complexes in chloroform: )-max nmj,..(~m3.mole-l.cm-1): 1-FeCl: 420 (124,000), 570 (136,00), 576 (5,400), 651.5 (3,500) and 673.5 (3,500); 1-MnCl: 377 (46,000), 400 (45,000), 469.5 (82,000), 517 (shoulder), 556.5 (11,600), 594 (shoulder) and 618 (shoulder); 2-MnCI: 377 (49,000), 400 (48,000), 472 (92,000), 521 (shoulder), 568 (12,400) and 618 (shoulder); 3-MnCI: 376 (46,000), 402 (39,000), 478 (100,000), 527 (shoulder), 582 (9,600) and 616 (9,200)
9
Methylene chloride was distilled over calcium hydride and kept on 4/~ molecular sieves.
10
The concentration ofpara-chlorostyrene epoxide was determined by gas chromatography on a OVl-15 m capillary column.
(Received in France 31 May 1991)