Synthesis, transformations, and comparative studies of porphyryl acrylic acids and their homologues

Article abstract of DOI:10.1021/jo8021764

The reactivity of porphyryl acrylates and their homologues was studied systematically and to establish their potential as building blocks for the synthesis of novel tetrapyrroles. A new synthetic approach for multifunctional porphyrins was developed using

Full text of DOI:10.1021/jo8021764

Synthesis, Transformations, And Comparative Studies of Porphyryl
Acrylic Acids and Their Homologues
Natalia N. Sergeeva,† Mohd B. Bakar,† and Mathias O. Senge*,†,‡
School of Chemistry, SFI Tetrapyrrole Laboratory, Trinity College Dublin, Dublin 2, Ireland, and
Medicinal Chemistry, Institute of Molecular Medicine, Trinity Centre for Health Sciences, Trinity College
Dublin, St James’s Hospital, Dublin 8, Ireland
sengem@tcd.ie
ReceiVed September 29, 2008
The reactivity of porphyryl acrylates and their homologues was studied systematically and to establish
their potential as building blocks for the synthesis of novel tetrapyrroles. A new synthetic approach for
multifunctional porphyrins was developed using R,ꢀ-unsaturated acyl porphyrins as versatile building
blocks with yields of 44-95%. The reaction of acyl chlorides generated in situ with ethyl diazoacetate
in the presence of PPh3 led to the corresponding phosphazine, which was quickly self-transformed into
a novel porphyrin ꢀ-keto ester system in up to 78% yield. Comparative studies of the next homologue
of acrylic porphyrins, i.e., those bearing an additional CH2 group next to the double bond of the R,ꢀ-
unsaturated fragment, showed that these can undergo rearrangement reactions via vinylketenes to yield
both regioisomers. Depending on the reaction conditions, this method gives regioselectively access to
either a rearrangement product or the product of esterification reactions in yields of 81% or 57%,
respectively. Enyne metathesis of novel propargyl esters with allyl porphyrins provided an easy access
to 1,3-disubstituted butadienes in up to 76% yield.
Introduction
Unsaturated acyl compounds are a subclass of these derivatives
and constituents of numerous natural and synthetic products
which display a wide range of biological activities. As multi-
modal groups they possess two reactively reverse sites (e.g.,
COX and CdC) suitable for C-C and C-X bond (trans)forma-
tions. The carbonyl unit is a versatile electrophile, while the
double bond can react as a nucleophile. Thus, depending on
the conditions and reagents used, these reactive sites can either
be activated or deactivated at the same time in a favorable
manner. Therefore, their chemistry offers significant synthetic
prospects based on different types of possible reactions (e.g.,
Claisen condensation and related acylations, substitutions, (1,2-
The chemistry of acyl compounds has a long history that can
be traced back to the early part of the last century.1 Acyl building
blocks derived from carboxylic acids are some of the best known
and most valuable synthons and are widely used in the synthesis
of organic fine chemicals. A variety of synthetic methodologies
has been developed to access these reactive molecules. R,ꢀ-
† School of Chemistry.
‡ Institute of Molecular Medicine.
(1) Gladstone, J. H. J. Chem. Soc., Trans. 1884, 45, 241–259. Purdie, T.;
Marshall, W. J. Chem. Soc., Trans. 1891, 59, 468–483. Bentley, W. H.; Perkin,
W. H. J. Chem. Soc., Trans. 1898, 73, 45–67.
1488 J. Org. Chem. 2009, 74, 1488–1497
10.1021/jo8021764 CCC: $40.75 2009 American Chemical Society
Published on Web 01/26/2009

Porphyryl Acryclic Acids
1,4- or cyclo)additions, to name a few) that can be carried out
to afford novel tetrapyrrole-based materials.
Only a few reports have been published using porphyrin benzoyl
acyl chlorides11,12,14 to leave the chemistry almost untouched.
Similarly, while the synthesis of acrylic porphyrins is well-
known,15 their chemistry remains relatively unexplored.
In the context of a program aimed at the development of novel
porphyrin bioconjugates suitable for cell targeting, we have
systematically studied the reactivity of porphyryl acyl acrylates
and their homologues. Here we present results on the synthesis,
transformation, and comparative studies of a series of porphyryl
acrylic derivatives.
Porphyrins and their derivatives are one of the most important
classes of heterocycles with unique properties. The practical
utilization of these macrocycles is expanding rapidly in emerging
areas such as cancer therapy, artificial photosynthesis, sensors,
nonlinear optics, nanomaterials, and use as pigments and
oxidation catalysts.2-4 These and many other possible applica-
tions of porphyrins require the development of new and more
efficient reactions to introduce functional groups into the
macrocycle. Broadly speaking, at present the chemistry available
for porphyrin modification is based on metal-catalyzed5 and
organolithium6 approaches that sometimes require special condi-
tions which leaves room for alternative synthetic methodologies.
Surprisingly, acyl chemistry has not been used much for the
modification of porphyrins. Several reports described the
utilization of porphyrin-benzoic acids7 as building blocks for
porphyrin thin films,7,8 and surface porphyrin monolayers for
use as sensor materials.8-12 Remarkably, functionalization of
these compounds involved mostly carbodiimide chemistry.7,13
Results and Discussion
1. Generation of Acyl Chlorides and Their Reactivity
toward Simple Nucleophiles. For our initial studies, we chose
3 and 4 with either one or two acroleinyl groups as model
compounds. Porphyrins 3 and 4 were synthesized via Heck
reaction from a bromoporphyrin 1 or 2 and methyl acrylate in
80-95% yields. They were easily hydrolyzed in KOH-EtOH
to the acrylic acids 5 and 6 in 80-95% yields (Scheme 1).The
corresponding acyl chlorides 7 and 8 were easily generated upon
treatment of 5 and 6 with SOCl2-THF in situ. Light heating
(35 °C) is essential to accelerate the formation of these green-
purple materials. Moreover, the acyl chlorides are moisture
sensitive, hydrolyzing back into the corresponding acids 5 and
6. Hence, they were used immediately in further transformations.
To evaluate the reactivity of these intermediates, we simply used
the nucleophiles such as ROH and R2NH. These studies have
shown that the acyl chlorides 7 and 8 in situ generated can be
easily converted into the novel porphyrin adducts 3b and 9-12
in good yields (Scheme 1).
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dimeric porphyrins. For example, the reaction of 7 with 5-(4-
hydroxyphenyl)-10,20-bis(3-methoxyphenyl)porphyrin 13 re-
sulted in the formation of dimer 14. Noteworthy, the first attempt
to carry out this reaction in THF shown to be successful for the
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However, replacement of THF by dichloromethane provided
dimer 14 in 51% (Scheme 2).
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Sergeeva et al.
SCHEME 1. Generation of Acyl Chlorides 7 and 8 and Synthesis of the Porphyrins 3b and 9-12
SCHEME 2. Synthesis of Porphyrin Dimer 14
as ꢀ-substituents can be converted into biologically active
phaeoporphyrins via photoinduced cyclization.16 While diazo
compounds are widely used as versatile precursors in synthetic
chemistry,17 surprisingly, only one strategy was applied for the
synthesis of diazo ꢀ-keto esters using acrylic acid halides in
the reaction of the latter with mercuryl diazoacetate reported
by Padwa et al.17 In this context, the reaction of acyl chloride
7 with ethyl diazoacetate in the presence of PPh3 offers an entry
into the important and unexplored class of porphyryl ꢀ-keto
esters. Acyl chloride 7 generated in situ was treated with a
mixture of ethyl diazoacetate and PPh3 in dichloromethane at
35 °C for several hours to give the phosphazine 15 in 70% yield
(Scheme 3). Some structural diversity was observed in solutions
of CDCl3 where slow conversion of 15 and formation of 16
was detected over the course of 7 days. Compound 16 trapped
in CDCl3 appears to be a product of partial hydrolysis of
phosphazine 15. However, compound 15 proved to be quite
unstable in dichloromethane and autotransformed (24 h) into
the stable ꢀ-keto ester 17 in 78% (Scheme 3). According to 1H
NMR data, porphyrin 17 exists only in the enol form in a
solution of either CDCl3 or CD2Cl2. More detailed NMR
analyses showed that compound 17 consists of only one
stereoisomer. Importantly, no response between either Hx and
Hz or in the pair of Hy with Hz were observed in 1D NOE
experiments. Strong NOE were detected for the CH2-group of
CO2Et and Hz, and also between Hx and Hy with ꢀ-Hs. These
results confirm that 17 has a 2E,4E-configuration as shown in
Scheme 3. Noteworthy, the synthesis of the ꢀ-keto esters are
generally requiring the hydrolysis of the phosphazines formed
in the reaction of the nonacrylic acid chlorides with diazoacetate
and further elimination of an NNH2 group.18 In our case, this
reaction offers a versatile approach to yield porphyryl hydroxy-
dienoates in just one step.
(16) Kenner, G. W.; McCombie, S. W.; Smith, K. M. J. Chem. Soc., Chem.
Commun. 1972, 844–845. Kenner, G. W.; McCombie, S. W.; Smith, K. M.
J. Chem. Soc., Perkin Trans. 1 1974, 4, 527–530. Cox, M. T.; Howarth, T. T.;
Jackson, A. H.; Kenner, G. W. J. Chem. Soc., Perkin Trans. 1 1974, 4, 512–
516. Cox, M. T.; Jackson, A. H.; Kenner, G. W.; McCombie, S. W.; Smith,
K. M. J. Chem. Soc., Perkin Trans. 1 1974, 4, 516–527.
(17) Regitz, M.; Maas, G. Diazo compounds. Properties and synthesis;
Academic: Orlando, FL, 1986. Doyle, M.; McKervey, M. A.; Ye, T. Reaction
synthesis with R-diazocarbonyl compounds; Wiley: New York, 1997. Padwa,
A.; Sa, M. M.; Weingarten, M. D. Tetrahedron 1997, 53, 2371–2386.
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Porphyryl Acryclic Acids
SCHEME 3. Reaction of 7 with Ethyl Diazoacetate via Formation of Phosphazine 15 and Conversion to 16 and 17
SCHEME 4. Synthesis and Transformations of Acrylic Esters 20-24
3. Homologues. The reactions of acyl chlorides bearing R-Hs
with tertiary amines is an old and common method for the
synthesis of ketenes and is often used for in situ generation,
e.g., in cycloadditions and other reactions typical for ketenes.19
Our investigations were further inspired by the fact that
substituted vinyl ketenes can be formed in situ by dehydroha-
logenation of R,ꢀ-unsaturated acyl chlorides, and as unstable
species, they can be activated and trapped.19,20Strategically, the
series of the next homologues of the acrylates 3 and 4 bearing
CH2 groups accessible for double-bond migration were
prepared using the metathesis approach for the synthesis of
R,ꢀ-unsaturated ketones reported by us earlier,21 followed
by ester hydrolysis. Metathesis of the allyl porphyrins 18,
19 and corresponding acrylate esters in the presence of
Grubbs II catalyst in dichloromethane provided an easy access
to the corresponding esters 20-22 in about 80-90% yield
(Scheme 4).
Unexpectedly, a first attempt to hydrolyze the methyl ester
23 in KOH-EtOH resulted in formation of a very polar
compound, which when treated with HCl (1 N) yielded 5 in
90%. The analytical data obtained were in accordance with the
structure of a product prepared through an alternative approach
via Heck reaction. In order to avoid basic conditions, we
considered an alternative approach for the synthesis of a
(18) Bestmann, H. J.; Kolm, H. Chem. Ber. 1963, 96, 1948–1958. Bestmann,
H. J.; Klein, O.; Goethlich, L.; Buckschewski, H. Chem. Ber. 1963, 96, 2259–
2265.
(19) Tidwell, T. T. Ketenes; Wiley: Hoboken, NJ, 2006. Tidwell, T. T Angew.
Chem., Int. Ed. 2005, 44, 5778–5785. Tidwell, T. T. Eur. J. Org. Chem. 2006,
563–576. Tiseni, P. S.; Peters, R. Angew. Chem., Int. Ed. 2007, 46, 5325–5328.
(20) Payne, G. B. J. Org. Chem. 1966, 31, 718–721. Truce, W. E., Jr. J.
Org. Chem. 1969, 34, 1341–1345.
(21) Sergeeva, N. N.; Lopez, V.; Senge, M. O. J. Organomet. Chem. 2008,
693, 2637–2640.
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Sergeeva et al.
SCHEME 5. Transformations of 26. Synthesis of 3b, 9, 27, and 28
porphyrin acrylic acid involving allyl porphyrin 18 and the
acrylic acid in the presence of Grubbs II catalyst. However,
test reactions gave the acroleinyl porphyrin 25 in 23% yield.
Similar transformations of (allyl porphyrinato)nickel(II) com-
plexes into porphyryl acroleinssalbeit catalyzed by Ni(OAc)2s
were recently reported by us.15 Finally, the tert-butyl ester 24
was successfully converted into the free acid 26 in the presence
of trifluoroacetic acid in dichloromethane in 95% (Scheme 4).
28 presented a mixture of stereomers in a ratio of 3:1, with an
overall yield for the two stereomers of 81% (Scheme 5).
1H NMR analysis confirmed the differences between 27 and
28 (here, data for the major stereoisomer 28E are given). The
signal for a double bond hydrogen atom Hx in 28E was shifted
to 8.76 ppm (d) compared to 5.83 ppm (d) for Hx′ in 27.
Likewise, the signals for the methylene hydrogen atoms (5.48
ppm, d) and a double-bond hydrogen atom Hy′ (7.92 ppm, dt)
in 27 were shifted toward higher field (3.79 ppm, d and 6.17
ppm, dt, respectively) in 28E. This confirms compound 28 to
be a rearrangement product. An analysis of the H NMR J
coupling constants of the CHdCH fragment in the stereomeric
mixture 28 (J for E 15.2 Hz and for Z 11.3. Hz) revealed the
stereochemistry of the major product to be E. This major
stereoisomer 28E was isolated in 59% yield. The formation of
both regioisomers 27 and 28 under different reaction conditions
suggests a competition20 of the two reaction pathways involving
substitution and elimination processes. The vinyl ketene is the
result of an elimination reaction causing a migration of the
double bond and formation of 28. The observation of the E/Z
mixture 28 suggests a pathway via a vinyl ketene intermediate
where the original stereochemistry is lost. In contrast, the
intermediate of the substitution reaction leading to the esteri-
fication product 27 is most likely a zwitterionic dienolate.
4. C-C Coupling Reactions. Enyne metathesis is a unique
and interesting transformation involving the reaction between
an alkene and an alkyne partner.22 We used enyne metathesis
starting from the propargyl ester 10 and the allyl porphyrins 18
and 29 to prepare the synthetically useful 1,3-disubstituted
The corresponding acyl chloride generated from porphyrin
26 by treatment with SOCl2 in THF reacted with piperidine in
the absence of NEt3 to give the compound 9 in 41% yield
(Scheme 5). Reaction of acyl chloride of 26 with MeOH and
N(i-Pr)2Et (4 equiv) led to the porphyrin 3b in almost quantita-
tive yield (95%). Analytical data for the compounds 3b and 9
prepared via these routes were the same as those derived for
the compounds prepared using the alternative approach outlined
in Scheme 1. The reaction pathway (mechanism) of 26 into 3b
and 9 seems to be similar to the one for the hydrolytic
conversion of 23 to 5, where “elimination” of a CH2 fragment
was observed, too. Assuming, that a vinyl ketene might be an
intermediate of these transformations; we slightly changed the
synthetic approach and used a bulky soft base (DMAP) and a
reactive propargyl alcohol. Indeed, the reaction of 26 with
propargyl alcohol provided only the esterification product 27
in 57% yield. However, traces of the rearrangement product 28
could be detected as well. In order to improve the yield of 28
and to confirm its structure, porphyrin 26 was alternatively
treated with a mixture of DMAP-EDAC (N-ethyl-N′-(3-
dimethylaminopropyl)carbodiimide) in dichloromethane, fol-
lowed by addition of propargyl alcohol. Surprisingly, two
regioisomeric products (27 and 28) were detected, with the
regioisomer 28 being the major product. Moreover, compound
1
3
(22) Blechert, S.; Connon, S. J. Angew. Chem., Int. Ed. 2003, 42, 1900–
1923, and references cited therein. (b) For the first report of enyne metathesis,
see: Katz, T. J.; Sivavec, T. M. J. Am. Chem. Soc. 1985, 107, 737–738.
1492 J. Org. Chem. Vol. 74, No. 4, 2009

Porphyryl Acryclic Acids
SCHEME 6. Enyne Metathesis of 10 and Allyl Porphyrins 18 and 29. Synthesis of 1,3-Disubstituted Butadienes 30 and 31
butadiene derivatives 30 and 31 (Scheme 6). Such compounds
offer themselves toward structural elaboration via Diels-Alder
and other cycloaddition reactions. We next compared the
reactivity and chemoselectivity of both generations of Grubbs
catalysts. Enyne metathesis of porphyrin 10 and the allyl
porphyrin 18 resulted only in formation of 30, with E/Z ) 3:2
in a good yield of 76%. Although stereochemistry of the reaction
of allyl porphyrinatonickel 29 and 10 using the same catalyst
was slightly improved to give E/Z ) 2:1, compounds 31 were
isolated in 41% yield. In the case of Grubbs II catalyst, a
competing CM homodimerization of the allyl porphyrin 18 took
place, resulting in a mixture of alkene 32 (31%, cis isomer)
and the 1,3-disubstituted butadiene derivatives 30 (55%)
(Scheme 6).
The assignment of the stereochemistry of the 1,3-disubstituted
butadienes 30 and 31 was based on NMR analyses involving
1D NOE, 2D-ROESY, HSQC, and HMBC experiments. For
the major stereomer in the 31E/Z mixture, ROESY experiments
showed a reliable correlation between Hx and Hb and between
Hy and Hz. A strong response was found for each of the Hx-Hb
and Hy-Hz pairs in 1D NOE as well. ROESY analysis of the
minor isomer of 31 showed the appropriate correlations between
Ha and Hz and between Hy and Hb. The stereochemistry of the
minor product in 31 could be assigned as Z and the major one
as the E-isomer as illustrated in Figure 1. Similar results were
obtained for the porphyrin 30. Thus, based on these analytical
data, the major stereomer has E stereochemistry in both mixtures
of 30 and 31.
porphyrins. Our studies show that the acyl chlorides 7 and 8
generated in situ can easily be converted using simple nucleo-
philes into the corresponding acyl derivatives. The reaction of
7 with ethyl diazoacetate via the instable phosphazine 15
represents a convenient entry into the important class of ꢀ-keto
esters 17. We could show that the phosphazine 15 was self-
converted into the ꢀ-keto ester, possibly via intermediate 16.
Interestingly, compound 17 exists only as the enol form in
halogenated solvents, and its stereochemistry was assigned as
the 2E,4E-configuration. The next homologues 23 and 26 of
the acrylic porphyrins (3 and 4), can undergo rearrangement
via vinyl ketenes under basic conditions to yield both regioi-
somers 27 and 28. Variation of the reaction conditions regi-
oselectively provides access to either a rearrangement (28, 81%)
or an esterification product (27, 57%). Finally, enyne metathesis
Conclusions
Based on acrylic porphyrins and some homologues, a new
synthetic approach has been developed for multifunctional
FIGURE 1. Assignments of the stereochemistry for the 1,3-disubsti-
tuted butadienes 30 and 31.
J. Org. Chem. Vol. 74, No. 4, 2009 1493

Sergeeva et al.
(2E,2′E)-3,3′-[(5,15-Diphenylporphyrinato-10,20-diyl)nickel(II)]-
diacrylic acid 6: violet solid (180 mg, 91%); mp >300 °C; Rf 0.1
of the novel propargyl esters with allyl porphyrins provided an
easy access to 1,3-disubstituted butadienes 30 and 31 in up to
76% yield. Porphyrin arrays can be constructed using cycload-
dition reactions based on the dimeric porphyrins 30-32
presented. The syntheses described provide access to the novel
porphyrins and expand the repertoire of the porphyrin based
reagents to be utilized for the further functionalization of the
porphyrin periphery. They can serve as versatile building blocks
for the facile transformation into porphyrin bioconjugates, e.g.,
amino and hydroxy acid derivatives, especially, for medicinal
applications.
1
(ethyl acetate/hexane, 1:2 v/v); H NMR (400 MHz, THF-d8) δ
6.24 (d, J ) 15.8 Hz, 2H), 7.71 (m, 6H), 7.97 (m, 4H), 8.72 (d, J
) 4.7 Hz, 4H), 9.40 (d, J ) 4.7 Hz, 4H), 9.80 (d, J ) 15.8 Hz,
2H), 11.28 (br, 2H); 13C NMR (100.6 MHz, THF-d8) δ 112.6, 120.6,
128.2, 129.1, 133.0, 134.2, 134.4, 134.5, 141.2, 142.3, 142.9, 143.5,
167.0; UV-vis (THF) λmax (log ε) 435 (4.2), 561 (3.2), 607 (3.2)
nm; TOF MS LD+ (C38H24N4NiO4) calcd for [M] 658.1151, found
658.1132.
General Procedure for Synthesis of 9-12: Generation of Acyl
Chloride 7 and Its Reactions with Nucleophiles. To a solution of
acid 5 (30 mg, 0.045 mmol) in anhydrous THF (4 mL) were added
SOCl2 (0.025 mL, 0.225 mmol) in 1 mL of THF and DMF (2-3
drops) under argon. The mixture was warmed to 35 °C and stirred
for 60 min (color change from red to green). The volatiles were
removed under reduced pressure, and the remaining acyl chloride
7 (purple-greenish solid) was dissolved in anhydrous CH2Cl2 (ca.
5 mL). The respective nucleophile (0.09-0.225 mmol) dissolved
in CH2Cl2 (ca. 2-5 mL) followed by NEt3 (0.013 mL, 0.09 mmol)
in CH2Cl2 (0.5 mL) were added, and the reaction was stirred for
several hours (TLC control) at 35 °C under argon. The reaction
mixture was filtered through a plug of silica and washed with
CH2Cl2, and the solvents were removed in vacuo. The crude
products were purified by flash chromatography on silica with
CH2Cl2/hexane or ethyl acetate/hexane to give the corresponding
porphyrins 9-11 (68-95%).
(E)-1-(Piperidin-1-yl)-3-[(5,10,15-triphenylporphyrinato-20-yl)nick-
el(II)]prop-2-en-1-one 9. To a solution of the acyl chloride 7
generated from 5 (30 mg, 0.045 mmol) in anhydrous CH2Cl2 (5
mL) were added piperidine (0.015 mL, 0.15 mmol) in CH2Cl2 (1
mL) and NEt3 (0.008 mL, 0.06 mmol) in CH2Cl2 (0.5 mL). The
reaction was stirred for 1 h (TLC control) at 35 °C under argon,
and the resulting mixture was worked up as described above. The
crude product was purified by flash chromatography on silica
(hexane/CH2Cl2, 2:1 v/v) to give 9 (18.2 mg, 83%) as a violet solid.
9 via 26: To a solution of acid 26 (30 mg, 0.044 mmol) in
anhydrous THF (5 mL) were added SOCl2 (0.016 mL, 0.22 mmol)
in 1 mL of THF and DMF (2-3 drops) under argon. The mixture
was stirred at 35 °C for 1 h. The volatiles were removed under
reduced pressure, and the remained acyl chloride was dissolved in
anhydrous CH2Cl2 (5 mL). Piperidine (0.031 mL, 0.309 mmol) in
CH2Cl2 (1 mL) was added to the reaction mixture, which was stirred
for 18 h (TLC control) at 35 °C under argon. The reaction mixture
was filtered through a plug of silica and washed with CH2Cl2, and
the solvents were removed in vacuo. The crude products were
purified by flash chromatography on silica (hexane/CH2Cl2, 1:1 v/v)
to give 9 (13.8 mg, 42%) as a violet solid: mp >300 °C; Rf 0.5
(ethyl acetate/hexane, 1:3 v/v); 1H NMR (400 MHz, CDCl3) δ 1.68
(m, 6H), 3.50 (m, 2H), 3.77 (m, 2H), 6.79 (d, J ) 15.8 Hz, 1H),
7.66 (m, 9H), 7.93 (m, 6H), 8.60 (m, 4H), 8.79 (d, 2H, J ) 4.4
Hz), 9.33 (d, 2H, J ) 4.4 Hz), 9.82 (d, J ) 15.8 Hz, 1H); 13C
NMR (100.6 MHz, CDCl3) δ 24.5, 25.7, 26.5, 29.7, 42.6, 47.3,
108.3, 109.7, 114.3, 120.1, 121.4, 127.1, 128.1, 131.2, 132.4, 133.0,
133.5, 134.2, 136.5, 140.0, 141.5, 141.8, 142.2, 143.2, 147.0, 165.9;
UV-vis (CH2Cl2) λmax (log ε) 423 (4.3), 538 (3.1) nm; TOF MS
LD+ (C46H35N5ONi) calcd for [M] 731.2195, found 731.2225.
(E)-Propargyl 3-[(5,10,15-Triphenylporphyrinato-20-yl)nick-
el(II)]acrylate 10. To a solution of acyl chloride 7 generated from
5 (30 mg, 0.045 mmol) in anhydrous CH2Cl2 (5 mL) were added
propargyl alcohol (0.013 mL, 0.225 mmol) in CH2Cl2 (1 mL) and
NEt3 (0.013 mL, 0.09 mmol) in CH2Cl2 (0.5 mL). The reaction
was stirred for several hours (TLC control) at 35 °C under argon,
and the resulting mixture was worked up as described above. The
crude product was purified by flash chromatography on silica
(CH2Cl2/hexane ) 1/1) to give 10 (31.7 mg, 73%) as a purple solid:
mp 143-158 °C dec; Rf 0.6 (CH2Cl2/hexane ) 1/1, v/v); 1H NMR
(400 MHz, CDCl3) δ 2.62 (br, 1H), 5.01 (br, 2H), 6.37 (d, J )
15.8 Hz, 1H), 7.71 (m, 9H), 7.99 (m, 6H), 8.68 (dd, J ) 4.7, 4.7
Experimental Section
All solvents were distilled prior to use. All reagents were
purchased from Sigma-Aldrich and were used without any further
purification. Allyl porphyrins (18, 19, and 29) and bromoporphyrins
1 and 2 were synthesized according to the procedures previously
reported.15,21 General experimental and analytical techniques used
were as described previously.15
Synthesis of the Compounds 3. A heterogeneous solution of a
bromoporphyrin 1 (0.32 mmol), methyl acrylate (0.29 mL, 3.2
mmol), PPh3 (252 mg, 0.96 mmol), Pd(OAc)2 (14.4 mg, 0.064
mmol), and K2CO3 (442 mg, 3.2 mmol) in toluene (120 mL) was
heated under argon at 110 °C for 36-48 h (TLC control). The
reaction mixture was filtered through a plug of silica and washed
with ethyl acetate. After removal of the solvents under reduced
pressure, the residue was recrystallized from CH2Cl2-MeOH to
give 3 in 80-95%. The analytical data for 3 were in accordance
with the data previously reported.15
(2E,2′E)-Dimethyl 3,3′-[(5,15-Diphenylporphyrinato-10,20-diyl)-
nickel(II)]diacrylate 4. A heterogeneous solution of (5,15-dibromo-
10,20-diphenylporphyrinato)nickel(II) 2 (200 mg, 0.32 mmol),
methyl acrylate (0.58 mL, 6.4 mmol), PPh3 (420 mg, 1.6 mmol),
Pd(OAc)2 (14.4 mg, 0.064 mmol), and K2CO3 (885 mg, 6.4 mmol)
in toluene (120 mL) was heated under argon at 110 °C for 72 h
(TLC control). The reaction mixture was filtered through a plug of
silica and washed with ethyl acetate. After removal of the solvents
under reduced pressure, the residue was recrystallized from
CH2Cl2-MeOH to give 4 (200 mg, 91%) as a green-violet solid:
mp >300 °C; Rf 0.7 (ethyl acetate/hexane, 1:2 v/v); 1H NMR (400
MHz, CDCl3) δ 3.97 (s, 6H), 6.28 (d, J ) 15.6 Hz, 2H), 7.71 (m,
6H), 7.95 (m, 4H), 8.75 (d, J ) 4.9 Hz, 4H), 9.31 (d, J ) 4.9 Hz,
4H), 9.81 (d, J ) 15.6 Hz, 2H); 13C NMR (100.6 MHz, CDCl3) δ
51.6, 110.5, 119.5, 126.7, 127.6, 131.3, 131.5, 133.0, 133.2, 139.3,
140.6, 141.3, 143.0, 166.2; UV-vis (CH2Cl2) λmax (log ε) 438 (5.3),
568 (4.2), 610 (4.3); TOF MS LD+ (C40H28N4NiO4) calcd for [M
+ Na] 709.1362, found 709.1369.
General Procedure for the Synthesis of 5 and 6 via Hydrolysis
with EtOH-KOH. To porphyrins 3 and 4 (0.3 mmol) in EtOH
(30 mL) was added an aqueous solution (2 mL) of KOH (400 mg).
The reaction was heated at 70 °C for 24-72 h (TLC control)
resulting in complete dissolution of the porphyrin. Ethanol was
removed under reduced pressure, and the violet solid left was treated
with HCl (1 N). The crystals formed were filtered off and washed
with HCl (1 N) (10 mL) and distilled H2O (20 mL). The free acid
was dried in vacuo to yield the products 5 and 6 (91-95%).
(E)-3-[(5,10,15-Triphenylporphyrinato-20-yl)nickel(II)]acrylic acid
5: purple solid (189 mg, 95%); mp >300 °C; Rf 0.2 (ethyl acetate/
hexane, 1:2 v/v); 1H NMR (400 MHz, CDCl3) δ 6.39 (d, J ) 15.4
Hz, 1H), 7.72 (m, 9H), 8.00 (m, 6H), 8.69 (m, 4H), 8.87 (d, J )
4.8 Hz, 2H), 9.42 (d, J ) 4.8 Hz, 2H), 10.03 (d, J ) 15.4 Hz, 1H);
13C NMR (150.9 MHz, CDCl3) δ 108.4, 119.6, 120.7, 126.8, 126.9,
127.8, 129.0, 131.0, 132.2, 132.7, 133.3, 133.4, 133.8, 140.0, 141.4,
142.1, 142.9, 146.7, 159.4, 169.9; UV-vis (CH2Cl2) λmax (log ε)
429 (5.3), 546 (4.3), 585 (4.2) nm; TOF MS LD+ (C41H26N4NiO2)
calcd for [M] 664.14, found 664.11.
1494 J. Org. Chem. Vol. 74, No. 4, 2009

Porphyryl Acryclic Acids
Hz, 4H), 8.85 (d, J ) 4.7 Hz, 2H), 9.39 (d, J ) 4.7, 2H), 9.97 (d,
J ) 15.8 Hz, 1H); 13C NMR (100.6 MHz, CDCl3) δ 51.9, 74.7,
108.6, 119.1, 120.1, 126.5, 126.6, 127.47, 127.5, 129.5, 130.9,
131.9, 132.4, 133.06, 133.1, 133.2, 133.3, 139.7, 141.0, 141.1,
141.7, 142.4, 144.7, 165.0; UV-vis (CH2Cl2) λmax (log ε) 429 (5.4),
547 (4.3), 587 (4.2) nm; TOF MS LD+ (C44H28N4NiO2) calcd for
[M] 702.1566, found 702.1531.
139.8, 141.2, 141.8, 142.5, 142.6, 145.6, 146.2 (br), 150.4, 157.6,
164.4; UV-vis (CH2Cl2) λmax (log ε) 413 (5.5), 432 (5.2), 508 (4.4),
543 (4.3), 585 (4.3), 635 (4.0) nm; TOF MS LD+ (C81H54N8NiO4)
calcd for [M + H] 1261.3700, found 1261.366.
Reaction of 7 with Ethyl Diazoacetate. Synthesis of 15-17.
Ethyl 2-(Triphenylphosphoranylidene)-5-[(5,10,15-triphenylpor-
phyrinato-20-yl)nickel(II)]azino-3-oxopent-4-enoate 15. Ethyl dia-
zoacetate (20.6 mg, 0.18 mmol) in CH2Cl2 (1 mL), PPh3 (47.3 mg,
0.18 mmol), and NEt3 (0.013 mL, 0.09 mmol) in CH2Cl2 (0.5 mL)
were added to a solution of acyl chloride 7 generated from 5 (30
mg, 0.045 mmol) in anhydrous CH2Cl2 (5 mL). The reaction was
stirred for 2 h (TLC control) at 35 °C under argon, and the resulting
mixture was diluted with hexane and quickly filtered through a short
column of silica. The volatiles were removed in vacuo, and the
solid residue was washed with hexane (3 × 5 mL) and dried under
vacuum to give 15 (32.2 mg, 70%) as a pale purple solid: Rf 0.4
(CH2Cl2/hexane, 1:1 v/v); 1H NMR (400 MHz, CD2Cl2) δ 1.45 (t,
J ) 7.0 Hz, 3H), 4.44 (q, J ) 7.0 Hz, 2H), 6.84 (d, J ) 15.4 Hz,
1H), 7.54 (m, 9H), 7.74 (m, 15H), 8.00 (m, 6H), 8.68 (dd, J ) 5.0
Hz, 5.0 Hz, 4H), 8.83 (d, J ) 5.0 Hz, 2H), 9.38 (d, J ) 5.0, 2H),
9.80 (d, J ) 15.4 Hz, 1H); 31P NMR (162 MHz, CD2Cl2) 44.26;
13C NMR (150.9 MHz, CD2Cl2) δ 14.2, 62.5, 110.2, 120.0, 120.8,
127.2, 127.3, 128.2, 128.7, 128.8, 131.2, 131.8, 131.9, 132.4, 132.5
(m), 132.9, 133.1, 133.6, 133.7, 133.8, 133.9, 136.0, 140.4, 140.5,
141.6, 141.7, 141.9, 142.6, 143.2, 145.8, 148.6, 162.6; TOF MS
LD+ (C63H45N6NiO3P) calcd for [M + 2H - O] 1008.2852, found
1008.2845; calcd for [M - H2O - PPh3] 745.1862, found 745.1868.
Ethyl 2-Diazenyl-5-[(5,10,15-triphenylporphyrinato-20-yl)nick-
el(II)]-3-hydroxypenta-2,4-dienoate 16. yield 12 mg (35%); Rf 0.6
(ethyl acetate/hexane, 2:1 v/v); 1H NMR (400 MHz, CDCl3) δ 1.38
(t, J ) 7.0 Hz, 3H), 4.32 (q, J ) 7.0 Hz, 2H), 6.75 (br, 1H), 7.35
(d, J ) 15.8 Hz, 1H), 7.71 (m, 9H), 7.99 (m, 6H), 8.67 (dd, J )
5.3 Hz, 5.0 Hz, 4H), 8.85 (d, J ) 5.3 Hz, 2H), 9.44 (d, J ) 5.3,
2H), 10.06 (d, J ) 15.8 Hz, 1H), 12.46 (br, 1H); UV-vis (CH2Cl2)
(E)-4-Bromophenyl 3-[(5,10,15-Triphenylporphyrinato-20-yl)-
nickel(II)]acrylate 11. To a solution of acyl chloride 7 generated
from 5 (30 mg, 0.045 mmol) in anhydrous CH2Cl2 (5 mL) were
added 4-bromophenol (15.6 mg, 0.09 mmol) in CH2Cl2 (1 mL) and
NEt3 (0.013 mL, 0.09 mmol) in CH2Cl2 (0.5 mL). The reaction
was stirred for several hours (TLC control) at 35 °C under argon,
and the resulting mixture was worked up as described above. The
crude product was purified by flash chromatography on silica
(CH2Cl2/hexane, 1:1 v/v) to give 11 (25.1 mg, 68%) as a violet
1
solid: mp 173 °C; Rf 0.25 (CH2Cl2/hexane ) 1/1, v/v); H NMR
(400 MHz, CDCl3) δ 6.50 (d, J ) 15.2 Hz, 1H), 7.24 (d, J ) 8.8
Hz, 2H), 7.61 (d, J ) 8.8 Hz, 2H), 7.71 (m, 9H), 7.99 (m, 6H),
8.66 (d, J ) 5.2 Hz, 2H), 8.70 (d, J ) 5.2 Hz, 2H), 8.87 (d, J )
5.2 Hz, 2H), 9.44 (d, J ) 5.2 Hz, 2H), 10.08 (d, J ) 15.2 Hz, 1H);
13C NMR (100.6 MHz, CDCl3) δ 108.3, 118.5, 119.3, 120.4, 123.1,
123.6, 125.1, 126.5, 126.6, 127.5, 127.6, 129.2, 130.8, 132.0, 132.1,
132.5, 132.6, 133.05, 133.1, 133.5, 139.7, 141.1, 141.8, 142.5,
145.7, 149.5, 163.9; UV-vis (CH2Cl2) λmax (log ε) 430 (5.3), 547
(4.3), 592 (4.3) nm; TOF MS LD+ (C47H29BrN4NiO2) calcd for
[M] 818.0827, found 818.0826.
(2E,2′E)-3,3′-[(5,15-Diphenylporphyrinato-10,20-diyl)nickel(II)]-
bis(1-(piperidin-1-yl)prop-2-en-1-one) 12. To a solution of acid 6
(30 mg, 0.045 mmol) in anhydrous THF (5 mL) were added SOCl2
(0.013 mL, 0.18 mmol) in 1 mL of THF and DMF (2-3 drops)
under argon, and the mixture was stirred for 2 h. The volatiles were
removed under reduced pressure, and the remaining purple-greenish
acyl chloride 8 was dissolved in anhydrous THF (5 mL). NEt3
(0.013 mL, 0.09 mmol) in THF (1 mL) was added, and stirring
was continued for 15 min. Piperidine (0.09-0.225 mmol) dissolved
in THF (1 mL) was added, and the reaction was stirred for 30 min
(TLC control) at rt under argon. The mixture was filtered through
a plug of silica and washed with ethyl acetate, followed by removal
of the solvents in vacuo. The residue was purified by flash
chromatography on silica with ethyl acetate/hexane ) 1:2 to give
12 (16 mg, 44%) as a green-purple solid: mp 282 °C; Rf 0.15 (ethyl
λ
max(A) 433 (1.0), 547 (0.1), 592 (0.09) nm; TOF MS LD+
(C45H32N6NiO3) calcd for [M + Na] 785.1787, found 785.1779.
(2E,4E)-Ethyl 3-Hydroxy-5-[(5,10,15-triphenylporphyrinato-20-
yl)nickel(II)]penta-2,4-dienoate 17. Phosphazine 15 (32 mg, 0.31
mmol) was dissolved in dichloromethane and allowed to stand for
24 h. The solvent was removed under reduced pressure, and the
residue was recrystallized from CH2Cl2-MeOH to give 17 (18 mg,
78%) as a violet solid: mp >300 °C; Rf 0.0 (ethyl acetate/hexane,
1:2 v/v); 1H NMR (600 MHz, CDCl3) δ 1.46 (t, J ) 7.0 Hz, 3H),
4.47 (q, J ) 7.0 Hz, 2H), 6.84 (d, J ) 15.2 Hz, 1H), 7.59 (s, 1H),
7.71 (m, 9H), 7.99 (m, 6H), 8.67 (dd, J ) 4.7, 4.7 Hz, 4H), 8.85
(d, J ) 5.2 Hz, 2H), 9.37 (d, J ) 5.2, 2H), 9.79 (d, J ) 15.2 Hz,
1H); 13C NMR (150.9 MHz, CDCl3) δ 14.2, 62.2, 109.7, 119.7,
120.6, 126.9, 127.0, 127.9, 128.0, 131.1, 132.4, 132.8, 133.5, 133.6,
133.7, 135.7, 140.2, 141.4, 141.6, 142.3, 142.9, 145.6, 147.8, 162.5;
UV-vis (CH2Cl2) λmax (log ε) 435 (5.8), 547 (4.8), 597 (4.8) nm;
TOF MS LD+ (C45H32N4NiO3) calcd for [M + 2H + 2Na]
782.1780, found 782.1621.
1
acetate/hexane ) 1/2, v/v); H NMR (400 MHz, CDCl3) δ 1.67
(m, 12H), 3.54 (m, 4H), 3.82 (m, 4H), 6.67 (d, J ) 15.2 Hz, 2H),
7.70 (m, 6H), 7.96 (m, 4H), 8.74 (d, J ) 4.7 Hz, 4H), 9.32 (d, J )
4.7 Hz, 4H), 9.80 (d, J ) 15.2 Hz, 2H); 13C NMR (100.6 MHz,
CDCl3) δ 24.2, 25.2, 26.3, 43.1, 46.6, 112.1, 119.0, 126.7, 127.6,
131.5, 132.7, 132.9, 133.0, 139.5, 140.6, 141.1, 164.0; UV-vis
(CH2Cl2) λmax (log ε) 436 (5.5), 557 (4.6), 604 (4.6) nm; TOF MS
LD+ (C48H42N6NiO2) calcd for [M] 792.2723, found 792.2720.
(E)-4-[5,15-Bis(3-methoxyphenyl)porphyrin-10-yl]phenyl 3-[(5,10,
15-Triphenylporphyrinato-20-yl)nickel(II)]acrylate 14. To a solu-
tion of acyl chloride 7 generated from 5 (30 mg, 0.045 mmol) in
anhydrous CH2Cl2 (5 mL) were added 5-(4-hydroxyphenyl)-10,20-
bis(3-methoxyphenyl)porphyrin 13 (26.3 mg, 0.43 mmol) in CH2Cl2
(1 mL) and NEt3 (0.013 mL, 0.09 mmol) in CH2Cl2 (0.5 mL). The
reaction was stirred for 24 h (TLC control) at 35 °C under argon,
and the resulting mixture was worked up as described above.
Purification by flash chromatography on silica (ethyl acetate/hexane,
1:2 v/v) afforded 14 (27.6 mg, 51%) as a purple solid: mp 247 °C;
Rf 0.8 (ethyl acetate/hexane, 1:2 v/v); 1H NMR (400 MHz, CDCl3)
δ -2.97 (s, 2H), 4.05 (s, 6H), 6.73 (d, J ) 15.8 Hz, 1H), 7.40 (m,
2H), 7.74 (m, 13H), 7.89 (m, 4H), 8.04 (m, 6H), 8.35 (m, 2H),
8.72 (dd, J ) 4.7, 4.7 Hz, 4H), 8.94 (d, J ) 4.7 Hz, 2H), 9.02 (dd,
J ) 4.7, 4.7 Hz, 4H), 9.12 (d, J ) 4.7 Hz, 2H), 9.37 (d, J ) 4.7
Hz, 2H), 9.58 (d, J ) 4.7 Hz, 2H), 10.28 (m, 2H); 13C NMR (100.6
MHz, CDCl3) δ 55.1, 104.5, 108.3, 113.1, 119.0, 119.3, 119.5,
120.2, 120.3, 126.6, 126.7, 127.3, 127.4, 127.5, 127.6, 129.8, 130.5,
131.0, 131.1 (br), 132.0, 132.5, 133.1, 133.2, 133.5, 134.9, 139.7,
General Procedure: Synthesis of 20-22 via Cross-Metathesis.
A mixture of allyl porphyrin (0.3 mmol), acrylate (1.5-3.0 mmol),
and Grubbs II catalyst (25.5 mg, 0.03 mmol) in dry CH2Cl2 (25
mL) was stirred at 35 °C under argon for 12 h (TLC control). The
solution was filtered through a plug of silica and washed with
CH2Cl2. The solvent was removed under reduced pressure followed
by recrystallization of the solid residue from CH2Cl2-MeOH to
give 20-22 (78-90%).
(E)-Methyl 4-[(5,10,15-Triphenylporphyrinato-20-yl)nickel(II)]-
but-2-enoate 20. Porphyrin 18 (174 mg, 0.3 mmol), methyl acrylate
(129 mg, 1.5 mmol), and Grubbs II catalyst (25.5 mg, 0.03 mmol)
gave 20 (153 mg, 80%) a violet solid: mp >300 °C; Rf 0.45 (ethyl
acetate/hexane, 1:5 v/v); 1H NMR (400 MHz, CDCl3) δ -2.74 (s,
2H), 3.55 (s, 3H), 5.72 (d, J ) 15.8 Hz, 1H), 5.87 (d, J ) 5.9 Hz,
2H), 7.76 (m, 9H), 7.94 (m, 1H), 7.99 (m, 6H), 8.81 (br, 4H), 8.91
(d, J ) 4.8 Hz, 2H), 9.34 (d, J ) 4.8 Hz, 2H); 13C NMR (100.6
MHz, CDCl3) δ 37.4, 51.4, 113.2, 120.0, 120.3, 123.0, 126.6, 127.8,
J. Org. Chem. Vol. 74, No. 4, 2009 1495

Sergeeva et al.
134.5, 142.0, 142.6, 150.7, 166.9; UV-vis (CH2Cl2) λmax (log ε)
419 (4.3), 517 (3.1), 553 (2.8), 657 (2.8) nm; HRMS (ES+)
[C43H32N4O2] calcd for [M + H] 637.2604, found 637.2596.
(E)-tert-Butyl 4-(5,10,15-Triphenylporphyrin-20-yl)but-2-enoate
21. Porphyrin 18 (174 mg, 0.3 mmol), tert-butyl acrylate (192 mg,
1.5 mmol), and Grubbs II catalyst (25.5 mg, 0.03 mmol) gave 21
(159 mg, 78%) as a violet solid: mp >300 °C; Rf 0.4 (ethyl acetate/
122.7, 126.8, 128.0, 134.4, 141.2, 141.8, 154.0, 192.4; UV-vis
(CH2Cl2) λmax (log ε) 429 (4.3), 523 (2.9), 570 (3.0), 660 (2.7),
666 (2.6) nm; HRMS (ES+) [C41H28N4O] calcd for [M + H]
593.2341, found 593.2357.
(E)-4-[(5,10,15-Triphenylporphyrinato-20-yl)nickel(II)]but-2-
enoic Acid 26. A solution of porphyrin 24 (100 mg, 0.136 mmol)
and TFA (0.85 mL) in CH2Cl2 (20 mL) was stirred at 35 °C for
12 h (TLC control). The solvents were removed under reduced
pressure, and the solid residue was dried in vacuo to give 26 (88
mg, 95%) as red solid: mp >300 °C; Rf 0.1 (CH2Cl2/hexane, 2:1
v/v); 1H NMR (400 MHz, CDCl3) δ 5.40 (d, J ) 4.8 Hz, 2H), 5.80
(d, J ) 15.6 Hz, 1H), 7.66 (m, 9H), 7.95 (m, 7H), 8.69 (br, 4H),
8.77 (d, J ) 5.0 Hz, 2H), 9.10 (d, J ) 5.0 Hz, 2H); 13C NMR
(100.6 MHz, CDCl3) δ 25.1, 31.0, 36.6, 111.9, 118.9, 119.2, 126.9,
127.8, 129.0, 132.4, 132.4, 133.2, 133.8, 140.7, 142.2, 142.5, 142.8,
154.0; UV-vis (CH2Cl2) λmax (lg ε) 415 (5.3), 529 (4.2) nm; TOF
MS LD+ (C42H28N4NiO2) calcd for [M] 678.1566, found 678.1564.
(E)-Propargyl 4-[(5,10,15-Triphenylporphyrinato-20-yl)nickel-
(II)]but-2-enoate 27. DMAP (15 mg, 0.124 mmol) in CH2Cl2 (1
mL) was added to a solution of the acyl chloride generated from
26 (42 mg, 0.062 mmol) in anhydrous CH2Cl2 (5 mL). The reaction
mixture was stirred for 10 min, and propargyl alcohol (0.036 mL,
0.62 mmol) in CH2Cl2 (0.5 mL) was added. Stirring was continued
for 1 h (TLC control) at 35 °C under argon. The resulting mixture
was filtered through a plug of silica and washed with CH2Cl2.
Purification using silica TLC plates (CH2Cl2/hexane, 1:2 v/v)
afforded 27 (25 mg, 57%) as a purple solid: mp >300 °C; Rf 0.4
1
hexane)1/5, v/v); H NMR (400 MHz, CDCl3) δ -2.70, 1.34 (s,
9H), 5.66 (d, J ) 15.8 Hz, 1H), 5.91 (d, J ) 5.8 Hz, 2H), 7.80 (m,
9H), 7.90 (dt, J ) 15.8, 5.8 Hz, 1H), 8.25 (m, 6H), 8.86 (br, 4H),
8.97 (d, J ) 4.7 Hz, 2H), 9.42 (d, J ) 4.7 Hz, 2H); 13C NMR
(100.6 MHz, CDCl3) δ 27.5, 36.8, 79.8, 113.2, 119.5, 119.8, 124.8,
126.2, 126.3, 127.3, 127.6 (br), 130.6 (br), 134.1, 141.5, 141.7,
148.8, 165.5; UV-vis (CH2Cl2) λmax (log ε) 418 (4.0), 444 (3.6),
516 (2.6), 550 (2.3), 594 (2.3), 654 (2.7) nm; HRMS (ES+)
[C46H38N4O2] calcd for [M + H] 679.3073, found 679.3085.
(2E,2′E)-Dimethyl 4,4′-[5,15-Triphenylporphyrin-10,20-diyl]di-
but-2-enoate 22. Porphyrin 19 (171 mg, 0.3 mmol), methyl acrylate
(258 mg, 3.0 mmol), and Grubbs II catalyst (25.5 mg, 0.03 mmol)
gave 22 (186 mg, 90%) as a violet solid: mp >300 °C; Rf 0.4 (ethyl
acetate/hexane, 1:2 v/v); 1H NMR (400 MHz, CDCl3) δ -2.68 (s,
2H), 2.75 (s, 6H), 3.56 (s, 6H), 5.74 (d, J ) 15.8 Hz, 2H), 5.91 (d,
J ) 5.3 Hz, 4H), 7.59 (m, 4H), 7.96 (dt, J ) 15.8, 5.3 Hz, 1H),
8.09 (m, 4H), 8.93 (d, J ) 4.7 Hz, 4H), 9.35 (d, J ) 4.7 Hz, 4H);
13C NMR (100.6 MHz, CDCl3) δ 22.3, 36.8, 51.0, 112.7, 119.5,
122.5, 127.0, 134.0, 137.0, 138.7, 150.3, 166.5; UV-vis (CH2Cl2)
λmax (log ε) 516 (4.1), 552 (4.0), 592 (3.0) nm; HRMS (ES+)
[C44H38N4O4] calcd for [M + H] 687.2971, found 687.2972.
(E)-Methyl 4-[(5,10,15-Triphenylporphyrinato-20-yl)nickel]but-
2-enoate 23. A mixture of porphyrin 20 (191 mg, 0.3 mmol) and
Ni(II)(acac)2 (308 mg, 1.2 mmol) in toluene (100 mL) was stirred
at 110 °C for 2 h (TLC control). The reaction mixture was filtered
through a plug of silica and washed with CH2Cl2. The solvents
were removed under reduced pressure, and the residue was
recrystallized from CH2Cl2-MeOH to give 23 (204 mg, 98%) as
a purple solid: mp >300 °C; Rf 0.33 (ethyl acetate/hexane, 1:5 v/v);
1H NMR (400 MHz, CDCl3) δ 3.60 (s, 3H), 5.36 (d, J ) 4.4 Hz,
2H), 5.81 (d, J ) 15.6 Hz, 1H), 7.67 (m, 9H), 7.82 (m, 1H), 7.98
(m, 6H), 8.71 (br, 4H), 8.77 (d, J ) 4.8 Hz, 2H), 9.13 (d, J ) 4.4
Hz, 2H); 13C NMR (100.6 MHz, CDCl3) δ 36.5, 51.5, 111.9, 118.8,
122.8, 126.9, 127.8, 129.2, 132.4, 133.1, 133.7, 140.7, 142.2, 142.3,
142.5, 142.7, 150.3, 166.9; UV-vis (CH2Cl2) λmax (lg ε) 416 (4.3),
530 (3.0) nm; TOF MS LD+ [C43H30N4O2Ni] calcd for [M + Na]
715.1620, found 715.1596.
1
(CH2Cl2/hexane, 1:1 v/v); H NMR (400 MHz, CDCl3) δ 2.35 (t,
J ) 2.3 Hz, 1H), 4.61 (d, J ) 2.3 Hz, 2H), 5.48 (d, J ) 5.8 Hz,
2H), 5.83 (d, J ) 15.6 Hz, 1H), 7.68 (m, 9H), 7.92 (dt, J ) 5.8
Hz, 15.6 Hz, 1H), 7.98 (m, 6H), 8.70 (s, 4H), 8.79 (d, J ) 5.0 Hz,
2H), 9.18 (d, J ) 5.0 Hz, 2H); 13C NMR (100.6 MHz, CDCl3) δ
36.6, 51.9, 74.8, 111.5, 118.8, 119.1, 122.3, 126.9, 127.78, 127.8,
129.2, 132.4, 133.2, 133.7, 140.7, 142.2, 142.3, 142.5, 142.7, 151.6,
165.6; UV-vis (CH2Cl2) λmax (log ε) 415 (4.7), 530 (3.7) nm; TOF
MS (C45H30N4NiO2) calcd for [M - H] 717.1598, found 717.1612.
(E)-Propargyl 4-[(5,10,15-Triphenylporphyrinato-20-yl)nickel-
(II)]but-3-enoate 28E. N-Ethyl-N′-(3-dimethylaminopropyl)carbo-
diimide hydrochloride (23.7 mg, 0.124 mmol) and propargyl alcohol
(0.036 mL, 0.62 mmol) were added to a solution of 26 (42 mg,
0.062 mmol) in anhydrous CH2Cl2 (5 mL) and DMAP (15 mg,
0.124 mmol). The reaction mixture was stirred for 12 h (TLC
control) at rt. The resulting mixture was filtered through a plug of
silica and washed with CH2Cl2. Purification by column chroma-
tography (CH2Cl2/hexane, 1:2 v/v) afforded 28-E/Z (ratio E/Z )
3:1, 36 mg, 81%) as a purple solid. Additional purification on silica
TLC plates (ethyl acetate/hexane ) 1/10) gave 28E (26.2 mg, 59%):
mp >300 °C; Rf 0.45 (CH2Cl2/hexane, 1:1 v/v); 1H NMR (400 MHz,
CDCl3) δ 2.57 (t, J ) 2.0 Hz, 1H), 3.79 (d, J ) 7.8 Hz, 2H), 4.88
(d, J ) 2.0 Hz, 2H), 6.17 (dt, J ) 7.8 Hz, 15.2 Hz, 1H), 7.71 (m,
9H), 8.00 (m, 6H), 8.71 (dd, J ) 4.9 Hz, 4.9 Hz, 4H), 8.76 (d, J
) 15.2 Hz, 1H), 8.82 (d, J ) 4.9 Hz, 2H), 9.38 (d, J ) 4.9 Hz,
2H); 13C NMR (100.6 MHz, CDCl3) δ 38.7, 52.1, 74.8, 113.4,
118.3, 118.5, 126.5, 127.3, 131.1, 131.76, 131.8, 132.2, 133.17,
133.2, 135.0, 140.2, 141.0, 141.4, 141.86, 141.9, 170.3; UV-vis
(CH2Cl2) λmax (log ε) 419 (5.2), 534 (4.1) nm; TOF MS LD+
(C45H30N4NiO2) calcd for [M] 716.1722, found 716.1746.
(E)-tert-Butyl 4-[(5,10,15-Triphenylporphyrinato-20-yl)nickel-
(II)]but-2-enoate 24. Compound 24 was prepared from 21 (203 mg,
0.3 mmol) using the same procedure as for the synthesis of 23.
Recrystallization from CH2Cl2-MeOH gave 24 (210 mg, 95%) as
a purple solid: mp >300 °C; Rf 0.75 (ethyl acetate/hexane, 1:5 v/v);
1H NMR (400 MHz, CDCl3) δ 1.40 (s, 9H), 5.26 (d, J ) 4.9 Hz,
2H), 5.73 (d, J ) 15.6 Hz, 1H), 7.70 (m, 10H), 8.03 (m, 6H), 8.78
(br, 4H), 8.81 (d, J ) 4.9 Hz, 2H), 9.13 (d, J ) 4.9 Hz, 2H); 13C
NMR (100.6 MHz, CDCl3) δ 28.1, 36.3, 80.4, 112.3, 118.8, 119.0,
124.9, 127.0, 127.9, 129.4, 132.4, 133.1, 133.8, 140.8, 142.2, 142.4,
142.5, 142.8, 148.8, 166.0; UV-vis (CH2Cl2) λmax (log ε) 416 (4.4),
530 (3.2) nm; TOF MS LD+ [C46H36N4O2Ni] calcd for [M]
734.2219, found 734.2192.
(E)-5-Acroleinyl-10,15,20-triphenylporphyrin 25. Grubbs II cata-
lyst (8.5 mg, 0.01 mmol) and acrylic acid (0.03 mL, 0.43 mmol)
were added to a solution of porphyrin 18 (51 mg, 0.09 mmol) in
dry CH2Cl2 (20 mL). The mixture was stirred for 18 h and then
filtered through a plug of silica eluting with CH2Cl2. Purification
by column chromatography (hexane/CH2Cl2, 2:1 v/v) gave 25 (12
mg, 0.02 mmol, 23%) as a purple solid: mp >300 °C; Rf 0.48 (ethyl
acetate/hexane, 1:3 v/v); 1H NMR (400 MHz, CDCl3) δ -2.40 (s,
2H), 7.16 (d, J ) 7.8 Hz, 15.6 Hz, 1H), 7.76 (m, 9H), 8.17 (m,
6H), 8.77 (dd, J ) 4.8, 4.8 Hz, 4H), 8.91 (d, J ) 4.8 Hz, 2H), 9.39
(d, J ) 4.8 Hz, 2H), 10.02 (d, J ) 15.6 Hz, 1H), 10.23 (d, J ) 7.8
Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 29.7, 32.0, 110.8, 121.7,
2-Methylene-5-[(5,10,15-triphenylporphyrin-20-yl)pent-3-enyl
3-[(5,10,15-Triphenylporphyrinato-20-yl)nickel(II)]acrylate 30.
The allyl porphyrin 18 (8.2 mg, 0.014 mmol) in dry CH2Cl2 (10
mL) was added dropwise under argon to a solution of porphyrin
propargyl ester 10 (10 mg, 0.014 mmol) and Grubbs I catalyst (2.34
mg, 0.003 mmol) in dry CH2Cl2 (10 mL). The reaction mixture
was stirred for 18 h at 35 °C and then filtered through a plug of
silica and washed with CH2Cl2. The volatiles were removed in
vacuo, and the remaining solid was purified by flash chromatog-
raphy on silica (hexane/CH2Cl2, 1:1 v/v) to yield 30 (13.9 mg, 76%,
E/Z 3:2) as a purple solid: mp >300 °C; Rf 0.3 (ethyl acetate/hexane,
1:5 v/v); UV-vis (CH2Cl2) λmax (log ε) 420 (4.0), 519 (3.0), 550
1496 J. Org. Chem. Vol. 74, No. 4, 2009

Porphyryl Acryclic Acids
(3.0), 596 (3.0), 656 (3.2) nm; TOF MS LD+ (C85H58N8O2Ni) calcd
(d, J ) 11.7 Hz, 1H, CHdCHCH2), 6.44 (d, J ) 15.4 Hz, 1H,
CHdCHCO), 6.77 (dt, J ) 6.4 Hz, 11.7 Hz, 1H, CHdCHCH2),
10.01 (d, J ) 15.4 Hz, 1H, CHdCHCO); 13C NMR (150 MHz,
CDCl3) δ 33.7 (CH2CHd), 67.4 (CH2OCO), 118.0 (CdCH2), 124.7
(CHdCHCH2), 130.8 (CHdCHCO), 136.9 (CHdCHCH2), 144.4
(CHdCHCO), 165.4 (CO2).
Synthesis of 30 and 32 Using Grubbs II Catalyst. The allyl
porphyrin 18 (8.2 mg, 0.014 mmol in 10 mL dry CH2Cl2) was added
dropwise under argon to a solution of the porphyrin propargyl ester
10 (10 mg, 0.014 mmol) and Grubbs II catalyst (2.41 mg, 0.003
mmol) in dry CH2Cl2 (10 mL). The reaction mixture was stirred
for 18 h at 35 °C and then filtered through a plug of silica. Flash
column chromatography on silica (hexane/CH2Cl2, 1:1 v/v) gave
30 (10 mg, 55%, E/Z 3:2) as the first fraction and 32 (18.2 mg,
31%) as the second fraction.
(Z)-1,4-Bis[5,10,15-triphenylporphyrin-20-yl]but-2-ene 32: yield
18.2 mg (31%); mp >300 °C; Rf 0.54 (ethyl acetate/hexane, 1:3
v/v); 1H NMR (400 MHz, CDCl3) δ -2.73 (s, 4H), 5.70 (br, 4H),
6.67 (br, 2H), 7.75 (m, 20H), 8.19 (m, 12H), 8.81 (br, 12H), 9.40
(d, 4H, J ) 5.2 Hz); 13C NMR (100.6 MHz, CDCl3) δ 29.27,
116.26, 119.18, 126.13, 126.26, 127.17, 128.36, 134.01, 134.07,
135.09, 141.80; UV-vis (CH2Cl2) λmax (lg ε) 420 (4.2), 517 (3.0),
551 (2.6), 593 (2.5), 650 (2.5) nm; HRMS (ES+) [C41H28N4O] calcd
for [M + H] 1129.4710, found 1129.4679.
1
for [M] 1280.4036, found 1280.4056; NMR key data (30E) H
NMR (600 MHz, CDCl3) δ 5.01 (m, 3H, CH2OCO, CdCHH), 5.24
(s, 1H, CdCHH), 5.93 (d, J ) 5.6 Hz, 2H, CH2CHd), 6.29 (d, J
) 15.8 Hz, 1H, CHdCHCH2) 6.30 (d, J ) 15.4 Hz, 1H,
CHdCHCO), 6.95 (dt, J ) 5.6 Hz, 15.8 Hz, 1H, CHdCHCH2),
9.83 (d, J ) 15.4 Hz, 1H, CHdCHCO); 13C NMR (150 MHz,
CDCl3) δ 38.0 (CH2CHd), 64.2 (CH2OCO), 116.8 (CdCH2), 130.9
(CHdCHCO), 134.2 (CHdCHCH2), 133.9 (CHdCHCH2), 144.2
(CHdCHCO), 165.3 (CO2); (30Z) 1H NMR (600 MHz, CDCl3) δ
5.30 (s, 2H, CH2OCO), 5.97 (s, 1H, CdCHH), 6.04 (s, 1H,
CdCHH), 6.16 (m, 3H, CH2CHd, CHdCHCH2), 6.48 (d, J ) 15.4
Hz, 1H, CHdCHCO), 6.83 (dt, J ) 6.8 Hz, 11.3 Hz, 1H,
CHdCHCH2), 10.03 (d, J ) 15.4 Hz, 1H, CHdCHCO); 13C NMR
(150 MHz, CDCl3) δ 35.1 (CH2CHd), 68.0 (CH2OCO), 118.2
(CdCH2), 124.2 (CHdCHCH2), 130.9 (CHdCHCO), 137.5
(CHdCHCH2), 144.5 (CHdCHCO), 165.6 (CO2).
2-Methylene-5-[(5,10,15-triphenylporphyrinato-20-yl)nickel(II)]-
pent-3-enyl 3-[(5,10,15-Triphenylporphyrinato-20-yl)nickel(II)]-
acrylate 31. The synthesis of 31 was carried out as described above
for 30 using the porphyrin propargyl ester 10 (10 mg, 0.014 mmol),
Grubbs I catalyst (2.34 mg, 0.003 mmol), and allyl porphyrin 29
(9.0 mg, 0.014 mmol). The mixture of 31 (7.8 mg, 41%, E/Z 2:1)
was obtained as as a purple solid: mp >300 °C; Rf 0.49 (ethyl
acetate/hexane, 1:5 v/v); UV-vis (CH2Cl2) λmax (log ε) 418 (4.0),
533 (2.9) 590 (2.0) nm; TOF MS LD+ (C85H56N8O2Ni2) calcd for
Acknowledgment. This work was supported by grants from
Science Foundation Ireland (SFI Research Professorship 04/
RP1/B482) and the Health Research Board (HRB Translational
Research Award 2007 TRA/2007/11).
1
[M + H] 1337.3311, found 1337.3322; NMR key data (31E) H
NMR (600 MHz, CDCl3) δ 5.02 (s, 2H, CH2OCO), 5.16 (s, 1H,
CdCHH), 5.31 (s, 1H, CdCHH), 5.46 (d, J ) 5.6 Hz, 2H,
CH2CHd), 6.29 (d, J ) 15.8 Hz, 1H, CHdCHCO), 6.43 (d, J )
16.2 Hz, 1H, CHdCHCH2), 6.84 (dt, J ) 5.6 Hz, 16.2 Hz, 1H,
CHdCHCH2), 9.82 (d, J ) 15.8 Hz, 1H, CHdCHCO); 13C NMR
(150 MHz, CDCl3) δ 36.8 (CH2CHd), 64.0 (CH2OCO), 117.0
(CdCH2), 130.4 (CHdCHCH2), 130.9 (CHdCHCO), 133.7
(CHdCHCH2), 144.0 (CHdCHCO), 165.3 (CO2); (31Z) 1H NMR
(600 MHz, CDCl3) δ 5.24 (s, 2H, CH2OCO), 5.68 (d, J ) 6.4 Hz,
2H, CH2CHd), 5.83 (s, 1H, CdCHH), 5.94 (s, 1H, CdCHH), 6.18
Supporting Information Available: Characterization data
including 1D and 2D NMR spectra of compounds 4-6, 9-12,
14-17, 20-28, and 30-32. This material is available free of
charge via the Internet at http://pubs.acs.org.
JO8021764
J. Org. Chem. Vol. 74, No. 4, 2009 1497