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6Порфирины
Porphyrins
Макрогэтэроцмклы
Статья
Paper
http://macroheterocycles.isuct.ru
DOI: 10.6060/mhc150664g
Application of Hydroxyporphyrins-Based Phosphite-Type Ligands to Asymmetric Pd-Catalyzed Allylic Substitution Reactions
Konstantin N. Gavrilov,a@ Sergey V. Zheglov,a Marina G. Maksimova,a
Ilya V. Chuchelkin,a Ivan M. Novikov,a Gelii V. Ponomarev,a,c Dina R. Erzina,a,b
and Igor S. Mikhela,b
aS.A. Esenin Ryazan State University, 390000 Ryazan, Russian Federation
hA.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 119071 Moscow, Russian Federation
cV.N. Orekhovich Institute of Biomedical Chemistry, 119121 Moscow, Russian Federation @Corresponding author E-mail: k.gavrilov@rsu.edu.ru
Diamidophosphite and phosphite ligands with (S)-2-(anilinomethyl)pyrrolidine or (S)-BINOL backbone and porphyrin cores were obtained. The use of these ligands provides up to 92 % ee (enantiomeric excess) in Pd-catalyzed asymmetric alkylation of (E)-1,3-diphenylallyl acetate with dimethyl malonate, up to 82 % ee in its sulfonylation with sodium p-toluene sulfinate and up to 76 % ee in its amination with pyrrolidine. Also, up to 90 % ee was achieved in Pd-catalyzed allylic alkylation of cinnamyl acetate with ethyl 2-oxocyclohexane-1-carboxylate. The influence of the structural moieties such as the nature of phosphorus-containing ring or porphyrin exocyclic substituent on the catalytic activity and enantioselectivity are discussed.
Keywords: Asymmetric allylic substitution, palladium, phosphites, diamidophosphites, porphyrins.
Применение основанных на гидроксипорфиринах лигандов фосфитного типа к Pd—катализируемым реакциям аллильного замещения
К. Н. Гаврилов,а@ С. В. Жеглов,а М. Г. Максимова,' И. В. Чучелкин,а И. М. Новиков,a Г. В. Пономарев,'Д. Р. Эрзина,аЬ И. С. МихельаЬ
Рязанский государственный университет им. С.А. Есенина, 390000 Рязань, Российская Федерация ьИнститут физической химии и электрохимии им. А.Н. Фрумкина РАН, 119071 Москва, Российская Федерация °Научно-исследовательский институт биомедицинской химии им. В.Н. Ореховича, 119121 Москва, Российская Федерация
@Е-шай: k.gavrilov@rsu.edu.ru
На основе (Б1)-2-(анилинометил)пирролидина или (Б)-BINOL получены диамидофосфитные и фосфитные лиганды, имеющие порфириновые циклы. Их использование в Pd-катализируемом асимметрическом алкилировании диметилмалонатом (Е)-1,3-дифенилаллилацетата позволило получить до 92 % энантиомерного избытка (ее), в его сульфонилировании пара-толуолсульфинатом натрия - до 82 % ее и в его аминировании пирролидином - до 76 % ее. Кроме того, до 90 % ее было достигнуто в Pd-катализируемом аллильном алкилировании этил-2-оксоциклогексанкарбоксилатом циннамилацетата. Обсуждается влияние на каталитическую активность и энантиоселективность таких структурных особенностей лигандов, как природа фосфорсодержащего цикла или экзоциклического порфиринового заместителя.
Ключевые слова: Асимметрическое аллильное замещение, палладий, фосфиты, диамидофосфиты, порфирины. 266 © ISUCT Publishing Макрогетероциклы / Macroheterocycles 2015 8(3) 266-273
Introduction
Asymmetric catalysis by transition metal complexes has rapidly grown from the point of a convenient synthetic approach to the organic and organoelement compounds with high enantiomeric purity. Such compounds are widely used as the main components of pharmaceuticals, agrochemicals, perfumery compositions, food additives, and fragrances.11"61 Activity and enantioselectivity of the metal complex catalysts are determined to a great extent by a proper design and synthesis strategy of the corresponding chiral ligands, first of all, phosphorus containing ligands, thousands representatives of which were used in various asymmetric transformations.11" 13] However, elaboration of an efficient asymmetric inductor for a given catalytic process often represents a challenge. The vast majority of known phosphorus-based chiral ligands in the corresponding metal complexes are able to catalyze (with different enantioselectivities) either a certain type of chemical transformation, or one certain reaction. There are very few versatile (the so-called 'privileged') ligands, and their high cost significantly limits their wide application. Therefore, the development of novel phosphorus-containing stereoselectors is ongoing and still in high demand.[1114-18]
Chiral phosphite-type compounds constitute a class of prominent ligands because they are favorably distinguished by resistance to oxidation, pronounced n-acidity, and are inexpensive. Also, they can be easily prepared from readily available starting materials via simple condensation processes, including those involving parallel and solidphase synthetic procedures.[5'71U218-31] In the case of P*-chiral phosphite-type ligands the presence of a stereogenic donor of phosphorus atom significantly promotes successful asymmetric induction in the key step of the catalytic cycle.
[2,17,18,32,33]
Catalytic systems based on chiral supramolecular ligands with phosphite moiety have recently attracted increasing attention.[34-38] In particular, phosphites and phosphoramidites with BINOL or TADDOL backbone and metalloporphyrin fragment have proven to be highly advantageous building blocks in creating large libraries of supramolecular ligands.[34-43] However, according to our best knowledge, there is only one brief mention of chiral phosphite bearing porphyrin core without a metal ion.[40] In this paper, we report on the preparation of a small series of phosphite and diamidophosphite ligands containing metal-free porphyrin framework, that we had subsequently explored in Pd-catalyzed asymmetric allylation reactions.
Pd-catalyzed enantioselective allylic substitutions have become one of the most powerful tools for asymmetric carbon-carbon and carbon-heteroatom bond formation, finding wide application in the total synthesis of valuable enantiomerically pure natural and unnatural compounds.[3'32,44-51] Furthermore, these reactions are the reliable instruments for ligands benchmark testing and the enantiomeric excesses obtained are the simplest scale for evaluating new chiral inductors.[44'5052] It should also be noted that construction of a quaternary carbon stereocenter via Pd-catalyzed enantioselective synthesis is highly challenging. From a drug discovery perspective, this method provides access to useful building blocks with a single quaternary stereocenter.[53,54]
Results and Discussion
The novel porphyrin-functionalized diamidophosphites 4a-c and phosphite 5 were synthesized by one step through the reaction of the corresponding hydroxyporphyrins 1a-c with one equivalent of the phosphorylating reagent 2 or 3 in the presence of Et3N or i-Pr2NEt as bases (Scheme 1). Ligands 4a-c and 5 were obtained in yields varying from 76 to 85 %; they can be stored in the solid form under dry conditions at room temperature for at least a few months with minimal degradation. Compounds 4a-c and 5 were fully characterized by 31P, 1H, and 13C NMR spectroscopy, MALDI TOF/ TOF mass spectrometry as well as by elemental analysis. Porphyrin-appended ligands 4a, 4c and 5 are metal-free, diamidophosphite-porphyrinato-zinc(II) compound 4b was prepared for comparison purposes.
As revealed by 31P and 13C NMR spectroscopy, exclusive formation of stereospecific diamidophosphites 4a-c with (^)-configuration at the P*-stereocentres occurred (see Table 1 and Experimental). Indeed, the 13C NMR spectra of these ligands are characterized by large spin-spin coupling constants 2Jc(8)p (35.6-38.5 Hz).
Table 1. 31P NMR chemical shifts and cone angles 0 of ligands 4a-c and 5.
Ligand Sp ppm 0,deg.
4a in C6D5CD3 6 5 3 123.3 121
4b in C6D5CD3 6 5 3 122.8 122
4c in C6D6 66 118.3 165
5 in CDCl3 143.3 146
These values suggest the ««//'-orientation of the pseudoequatorial exocyclic substituent at the phosphorus atom and the -(CH2)3- part of the pyrrolidine fragment of the phosphabicyclic skeleton and, consequently, the syn-orientation of the phosphorus lone pair with respect to the C(8) atom (Figure i).[i3.i8.55-59]
H
Figure 1. Stereochemistry of the phosphabicyclic part in ligands 4a-c (X = exocyclic substituent).
In order to have an estimation of the steric bulk of ligands 4a-c and 5, we calculated their Tolman cone angles[60] by the reported method using semi-empirical quantum-mechanical AM1 techniques with full optimization of geometrical parameters.[61] The obtained results (Table 1) show that the steric parameters (0) of 4a-c and 5 vary within the interval of 121°-165°, peaking at diamidophosphite 4c. Compounds 4a,b and 5 are characterized by moderate steric demands (0 = 121°-146°), while 4c appears to be rather
Scheme 1. Synthesis of diamidophosphites 4a-c and phosphite 5.
bulky ligand (6 = 165o).[60=62'631 It should be noted that ligands bearing P*-chirogenic phosphorus atoms and porphyrin or metalloporphyrin fragments were prepared for the first time.
The first set of catalytic runs was carried out employing racemic (£)-1,3-diphenylallyl acetate 6, which is a widespread substrate for asymmetric allylic substitutions. As nucleophilic agents, sodium /»-toluene sulfinate, dimethyl malonate and pyrrolidine were used (Table 2-4). The catalysts were generated in situ from [Pd(allyl)Cl]2 and the ligands at 1:1 and 2:1 L/Pd molar ratios.
The results achieved with /-TolSO2Na as the S-nucleophile are summarized in Table 2. Zinc(II)-containing ligand 4b was the most efficient, and (S)-7a was formed with 89 % yield and 82 % ee (Table 2, entry 4). The analogous catalysts based on metal-free diamidophosphite 4a showed a somewhat lower enantioselectivity: up to 70 % ee for (S)-7a was achieved in this case (Table 2, entries 1 and 2). Compound 4c afforded sulfone (S)-7a with rather good enantiomeric purity (up to 78 % ee). In general, chemical yield and especially asymmetric induction were poorly sensitive to the L/Pd molar ratio. Unfortunately, palladium catalysts with phosphite 5 gave no conversion in the synthesis of 7a.
Table 3 shows the results obtained in Pd-catalyzed asymmetric allylic alkylation of substrate 6. The most sterically demanding ligand 4c provided quantitative conversion of the starting substrate and enantioselectivities of up to 92 % (Table 3, entries 9-12). The best result was
Table 2. Pd-catalyzed allylic sulfonylation of (,E)-1,3-diphenylallyl acetate 6 with sodium /-toluene sulfinate a.
Ph
OAc
Ph
NaSO2pTol, cat
THF
O=S=O
Ph^v-^Ph
7a
Entry Ligand L/Pd Yield, % ee, %b
1 4a 1 78 70 (S)
2 4a 2 82 67 (S)
3 4b 1 84 80 (S)
4 4b 2 89 82 (S)
5 4c 1 61 78 (S)
6 4c 2 68 77 (S)
aAll reactions were carried out with 2 mol % of [Pd(allyl)Cl]2 in THF at room temperature for 48 h.
bEnantiomeric excess of 7a was determined by HPLC (Daicel Chiralcel OD-H, C6H14/i-PrOH = 4/1, 0.5 ml/min, 254 nm, t(R ) = 16.3 min, t(S) =18.5 min).
obtained in THF at L/Pd = 2. Both diamidophosphites 4a and 4b have afforded the desired product (S)-7b with 76 % and 75 % ee, respectively. Catalytic systems based on 4a have demonstrated better activity (Table 3, entries 1-4 and
6
5-8). In all cases, with participation of ligands 4a and 4b, the higher enantioselectivity was observed in CH2Cl2 as well as at the molar ratio L/Pd = 2. Compound 5 has allowed the synthesis of product (R)-7b with excellent conversion, but with low enantiomeric purity (no more than 22 % ee).
As a whole, catalytic performance in the Pd-catalyzed allylic amination of 6 with pyrrolidine as a N-nucleophile followed the same trend as for its allylic alkylation. In particular, the amination process with participation of diamidophosphite 4c has resulted in quantitative conversion and enantioselectivity up to 76 % ee (Table 4, entries 9-12). Ligands 4a and 4b have provided lower levels of asymmetric induction (64 % and 54 % ee, respectively, Table 4, entries 3 and 6). Phosphite 5 with binaphthyl backbone was again practically inefficient (ee does not exceed 25 %).
We have also screened ligands 4a-c and 5 in the allylic alkylation of cinnamyl acetate 8 with ethyl 2-oxocy-clohexane-1-carboxylate 9 (Table 5); this is a transformation where a quaternary stereogenic center is generated in the nucleophile. The reaction was performed in toluene in the presence of allylpalladium(II) chloride dimer as the pre-catalyst. Enantioselection occurs when the n-allyl-ligand complex differentiates between the prochiral faces of the approaching reagent. In this mechanism, where the nucleo-phile attacks on the face of the n-allyl system opposite to that of the chirality inducing metal-ligand complex, the generation of asymmetry appears to be relatively challenging.^18,5^ Both related diamidophosphites 4a and 4b have provided practically equal very good results: enantio-
meric quaternary-substituted product (S)-10 was obtained in 100 % conversion, 88 % ee and 99 % conversion, 90 % ee, respectively (Table 5, entries 2 and 4). Catalysts based on 4c have proved to be less efficient: 83 % conversion and 78 % ee for (S)-10 were achieved in this case. The use of phosphite 5 has generated an almost racemic product 10. It is clear that for all ligands the optimal L/Pd molar ratio is 2.
Conclusion
In summary, we have designed, synthesized and characterized some novel phosphite-type chiral ligands containing oxyporphyrin groups. In asymmetric Pd-catalyzed allylic substitution, metal-free P*-chiral diamidophosphites 4a and 4c as well as zinc(II)-containing 4b are quite efficient as complementary asymmetric inducers. On the contrary, phosphite 5 with (Sa)-binaphthyl backbone has provided much lower activity and enantioselectivity. As a whole, di-amidophosphite-functionalized porphyrins with stereogenic phosphorus atoms are very attractive for further screening in transition metal catalyzed asymmetric reactions. Such investigations are currently in progress in our laboratories.
Experimental
31P, 13C and 1H NMR spectra were recorded on a Bruker Avance III 600 (242.9 MHz for 31P, 150.9 MHz for 13C and 600.13 MHz
Table 3. Pd-catalyzed allylic alkylation of (,E)-1,3-diphenylallyl acetate 6 with dimethyl malonatea.
MeO2C^,XO2Me
CH2(CO2Me)2, cat
Ph
OAc Ph
6
Solvents
Ph ^^ Ph 7b
Entry Ligand L/Pd Solvent Conversion, % ee, % b
1 4a 1 CH2Cl2 100 69 (S)
2 4a 2 CH2Cl2 100 76 (S)
3 4a 1 THF 91 67 (S)
4 4a 2 THF 90 69 (S)
5 4b 1 CH2Cl2 88 68 (S)
6 4b 2 CH2Cl2 62 75 (S)
7 4b 1 THF 87 62 (S)
8 4b 2 THF 53 70 (S)
9 4c 1 CH2Cl2 100 83 (S)
10 4c 2 CH2Cl2 100 84 (S)
11 4c 1 THF 100 87 (S)
12 4c 2 THF 100 92 (S)
13 5 1 CH2Cl2 98 17 (R)
14 5 2 CH2Cl2 94 22 (R)
15 5 1 THF 0 -
16 5 2 THF 0 -
aAll reactions were carried out with 2 mol % of [Pd(allyl)Cl]2 at room temperature for 48 h (BSA, KOAc).
bThe conversion of substrate 6 and enantiomeric excess of 7b were determined by HPLC (Daicel Chiralcel OD-H, C6H14/i-PrOH = 99/1, 0.3 ml/min, 254 nm, t(R) = 28.0 min, t(S) = 29.3 min).
Table 4. Pd-catalyzed allylic amination of (,E)-1,3-diphenylallyl acetate 6 with pyrrolidine1.
OAc s HN(CH2)4, cat Q __ 1*
Ph 6 Ph Solvents ' Ph' 7c
Entry Ligand L/Pd Solvent Conversion, % ee, % b
1 4a 1 CH2Cl2 100 53 (R)
2 4a 2 CH2Cl2 100 54 (R)
3 4a 1 THF 80 64 (R)
4 4a 2 THF 75 55 (R)
5 4b 1 CH2Cl2 99 44 (R)
6 4b 2 CH2Cl2 96 54 (R)
7 4b 1 THF 71 48 (R)
8 4b 2 THF 89 52 (R)
9 4c 1 CH2Cl2 100 70 (R)
10 4c 2 CH2Cl2 100 75 (R)
11 4c 1 THF 100 75 (R)
12 4c 2 THF 100 76 (R)
13 5 1 CH2Cl2 24 10 (R)
14 5 2 CH2Cl2 30 5 (R)
15 5 1 THF 10 25 (R)
16 5 2 THF 19 16 (R)
aAll reactions were carried out with 2 mol% of [Pd(allyl)Cl]2 at room temperature for 48 h.
bThe conversion of substrate 6 and enantiomeric excess of 7c were determined by HPLC (Daicel Chiralcel OD-H, C6H14//-PrOH/HN(Et)2 = 200/1/0.1, 0.9 ml/min, 254 nm, t(R) = 5.0 min, t(S) = 6.1 min).
Table 5. Pd-catalyzed allylic alkylation of cinnamyl acetate 8 with ethyl 2-oxocyclohexane-1-carboxylate 9a.
O O A« 9 Et^O
Ph^^^OAc 8 + 6 cat PhCH3 10
Entry Ligand L/Pd Conversion, % ee, %b
1 4a 1 68 74 (S)
2 4a 2 100 88 (S)
3 4b 1 55 68 (S)
4 4b 2 99 90 (S)
5 4c 1 58 55(S)
6 4c 2 83 78 (S)
7 5 1 0 -
8 5 2 16 12 (S)
aAll reactions were carried out with 2 mol % of [Pd(allyl)Cl]2 in toluene at room temperature for 48 h (BSA, Zn(OAc)2).
bThe conversion of substrate 8 and enantiomeric excess of 10 were determined by HPLC (Kromasil 5-CelluCoat, C6H14//-PrOH = 95/5, 0.4
ml/min, 254 nm, t(R) = 14.3 min, t(S) = 16.4 min).
for Щ) spectrometer. The assignment of the resonances in the Щ and 13C NMR spectra was achieved by the use of DEPT, COSY, and HSQC techniques and published data.[55-57] Chemical shifts (ppm) are given relative to Me4Si ('H and 13C) and 85 % H3PO4 (31P NMR). Data are represented as follows: chemical shift, multiplicity (br = broad, s = singlet, d = doublet, t = triplet, m = multiplet); coupling constants nJ in Hz integration, «n» values are reported in the case of their unambiguous determination. Mass spectra were recorded on a Braker Daltonics Ultraflex spectrometer (MALDI TOF/TOF). Optical rotations were measured on an Atago AP-300 polarimeter. HPLC analyses were performed on Agilent 1100 and Stayer instruments using Chiralcel® and Kromasil® columns. Elemental analyses were performed on a CHN-microanalyzer Carlo Erba EA1108 CHNS-O.
All reactions were carried out under a dry argon atmosphere in flame-dried glassware and in freshly dried and distilled solvents. For example, toluene and tetrahydrofuran were freshly distilled from sodium benzophenone ketyl before use; dichloromethane was distilled from NaH. Triethylamine, N,N-diisopropylethylamine and pyrrolidine were distilled over KOH and then over a small amount of LiAlH4 before use. Thin-layer chromatography was performed on E. Merck pre-coated silica gel 60 F254 and Macherey-Nagel Alugram Alox N/UV254 plates. Column chromatography was performed using silica gel MN Kieselgel 60 (230-400 mesh) and MN-Aluminum oxide, basic, Brockmann Activity I. 4-(10,15,20-Triphenylporphyrin-5-yl) phenol 1a, 5-(4-hydroxyphenyl)-10,15,20-triphenylporphyrinyl-K4N21,N22,N23,N24-zinc(II) 1b and (5,10,15,20-tetraphenylporphyrin-2-yl)methanol 1c were prepared using known procedures. [42-64"66] Phosphorylating reagents (5S)-2-chloro-3-phenyl-1,3-diaza-2-phosphabicyclo[3.3.0]octane 2 and (Sa)-4-chlorodinaphtho[2,1-d:r,2'-/][1,3,2]dioxaphosphepine 3 were prepared as published. [5667] The [Pd(allyl)Cl]2 and starting substrate 6 were obtained as published.[68] Pd-catalyzed reactions: allylic sulfonylation of (E)-1,3-diphenylallyl acetate 6 with sodium p-toluene sulfinate, alkylation with dimethyl malonate, amination with pyrrolidine and allylic alkylation of cinnamyl acetate 8 with ethyl 2-oxocyclohexane-1-carboxylate 9 were performed according to the appropriate procedures.[535669]
(Sa)-BINOL, sodium p-toluene sulfinate, dimethyl malonate, BSA (N,0-bis(trimethylsilyl) acetamide), cinnamyl acetate 8 and ethyl 2-oxocyclohexane-1-carboxylate 9 were purchased from Aldrich and Acros Organics and used without further purification.
General procedure for the preparation of ligands 4a-c and 5. To a vigorously stirred solution of the appropriate phosphorylating reagent (1 mmol) and Et3N (0.70 ml, 5 mmol) or i-Pr2NEt (in the synthesis of 4b, 0.87 ml, 5 mmol) in toluene (15 ml) relevant hydroxyporphyrin (1 mmol) was added in one portion. The mixture was stirred at reflux for 5 min, and cooled to 20 °C. The resulting suspension was filtered through a short plug of aluminum oxide, the column was washed twice with toluene (5 ml), and the solvent was evaporated under reduced pressure (40 Torr). The residue was additionally purified by flash chromatography on silica gel (toluene).
(2R,5S)-2-(4-(10,15,20-Triphenylporphyrin-5-yl)phenoxy)-3-phenyl-1,3-diaza-2-phosphabicyclo [3.3.0]octane (4a). Maroon-purple powder (0.69 g, yield 83%). [a]D23 = - 214.5° (c 1.0, toluene). Found, %: C, 79.46; H, 5.42; N, 10.17. C„H N OP. Calculated, %:
55 43 6
C, 79.12; H, 5.19; N, 10.07. Mass spectra (MALDI TOF/TOF) m/z (%): 835 (100) ([M + H]+), 631 (52) ([C44H30N4O + H]+). 1H NMR (600.13 MHz, C6D5CD3, 25 °C) SH ppm: -2.29 (br. s, 2 H, NH), 1.11-1.17 (m, 1 H, C(6)H2), 1.40-1.48 (m, 2 H, C(7)H2), 1.56-1.61 (m, 1 H, C(6)H2), 2.88-2.92 (m, 1 H, C(4)H2), 3.10-3.16 (m, 1 H, C(8)H2), 3.42 (dd, 3JHH = 7.8, 3JHH = 9.0, 1 H, C(4)H2), 3.46-3.52 (m, 1 H, C(8)H2), 3.76-3.81 (m, 1 H, C(5)H), 6.89 (tt, 3JHH = 6.6, JHH = 1.8, 1 H, Ar.), 7.26-7.31 (m, 4 H, Ar.), 7.34 (d, 3JHH = 8.4, 2 H, Ar.), 7.44-7.50 (m, 9 H, Ar.), 7.93 (d, 3JHH = 8.4, 2 FI, Ar.), 8.07-8.11 (m, 6 H, Ar.), 8.85 (br. s, 4 H, Ar.), 8.88 (d,
3JHH = 4.8, 2 H, Ar.), 8.90 (d, 3JHH = 4.8, 2 H, Ar.). 13C NMR (150.9 MHz, C6D5CD3, 25 °C) SC ppm:' 26.6 (d, 3JCP = 4.5, C(7)), 32.1 (s, C(6)), 48.0 (d, 3JCP = 35.6, C(8)), 54.3 (d, 2JCP = 8.1, C(4)), 63.5 (d, 2JCP = 8.8, C(5)), 115.9 (d, 3JCP = 13.0, CHJ, 119.9 (d, JC P = 0.9, CHj, 120.46 (s, Cat), 120.52 '(s, Cat), 120.7 (d, J„ = 4.7c ' CHJ, 126.9 (s, CHJ, 127.8 (s, CHJ, 129.7 (s, CHJ, 131.4 (very br., CHJ, 134.9 (s, CHJ, 135.7 (s, CHJ 137.6 (s, Cat), 142.96 (s, Cat), 143.0 (s, Cat), 146.0 (d, 2Jcp = 15.2, Cph), 154.6 (d, = 5.3, POC). 31P NMR (242.9 MHz, C6D5CD3, 25 °C) SP ppm: 123.3.
(2R,5S)-2-(4-(10,15,20-Triphenyl-zinc(lI) porphyrin-5-yl) phenoxy) -3-phenyl-1,3-diaza-2-phosphabicyclo[3.3.0]octane (4b). Maroon-purple powder (0.68 g, yield 76 %). [a]D23 = -262.2° (c 1.0, toluene). Found, %: C, 73.83; H, 4.74; N, 9.04. C55H41N6OPZn. Calculated, %: C, 73.54; H, 4.60; N, 9.36. Mass spectral (MALDI TOF/TOF) m/z (%): 897 (10) ([M + H]+), 693 (12) ([C44H28N4OZn + H]+), 206 (100) ([C11H15N2P]+). 1H NMR (600.13 MHz, C6D5CD3, 23 °C) SH ppm: 1.16-1.222 (m, 1 H, C(6)H2), 1.46-1.54 (m, 2 H, C(7)H2), 1.62-1.68 (m, 1 H, C(6)H2), 2.93-2.97 (m, 1 H, C(4) H2), 3.16-3.21 (m, 1 H, C(8)H2), 3.47 (dd, 3JHH = 7.8, 3JHH = 9.0, 1 H, C(4)H2), 3.50-3.56 (m, 1 H, C(8)H2), 3.81-3.86 (m, 1 H, C(5) H), 6.94 (tt, 3JHH = 6.6, JHH = 1.8, 1 H, Ar.), 7.30-7.33 (m, 4 H, Ar.), 7.35 (d, 3JHH = 8.4, 2' H, Ar.), 7.67-7.61 (m, 9 H, Ar.), 8.10 (d, 3JHH = 8.4, 2 H, Ar.), 8.28-8.31 (m, 6 H, Ar.), 9.04 (br. s, 4 H, Ar.), 9.07 (d, 3JHH = 4.8, 2 H, Ar.), 9.08 (d, 3JHH = 4.8, 2 H, Ar.). 13C NMR (150.9 MHz, C6D5CD3, 23 °C) SC ppm: 26.6 (d, 3JCP = 4.4, C(7)), 32.2 (s, C(6)), 48.0 (d, 2JCP = 35.7, C(8)), 54.4 (d, J, = 8.1, C(4)), 63.5 (d, 2JCP = 8.9, C(5))c 115.9 (d, 3JCP = 13.0, CHj, 119.8 (s, CHJ, 120.6 (d, J,P = 4.2, CHJ, 120.97 (s, CJ, 121.0 (s, CJ, 121.1 (s, Cat), 126.7 ' (s, CHJ, 127.5 (s, CHJ, 129.7 (s, CHJ, 132.0 (s, CHJ, 132.1 (s, CHJ, 134.9 (s, CHJ, 135.6 (s, CHJ, 137.6 (s, CJ, 143.99 (s, CJ, 144.0 (s, CJ, 1A0.45 (d, 2JCP = 2.3, POC), 150.6 (d, 2JCP = 15.8, CPh). 31P NMR (242.9 MHz, C6D5CD3, 23 °C) SP ppm: 122.8.
(2R, 5S)-2-((5,10,15,20-Tetraphenylporphyrin-2-yl)methoxy) -3-phenyl-1,3-diaza-2-phosphabicyclo [3.3.0]octane (4c). Maroon-purple powder (0.72 g, yield 85%). [a]D23 = -193.2° (c 1.0, toluene). Found, %: C, 79.52; H, 5.44; N, 10.07. C H N OP. Calculated, %:
56 45 6
C, 79.23; H, 5.34; N, 9.90. Mass spectra (MALDI TOF/TOF) m/z (%): 849 (11) ([M + H]+), 629 (100) ([C45H32N4 + H]+). 1H NMR (600.13 MHz, C6D6, 27 °C) SH ppm: -2.15 (b>r. s, 2 H, NH), 1.131.18 (m, 1 H, C(6)H2), 1.27-1.39 (m, 2 H, C(7)H2), 1.55-2.61 (m, 1 H, C(6)H2), 2.83-2.90 (m, 2 H, C(4)H2 and C(8)H2), 3.33-3.39 (m, 2 H, C(4)H2 and C(8)H2), 3.66-3.71 (m, 1 H, C(5)H), 4.97 (dd, 2JHH = 15.02 3JHP = 5.4, 1 H, CH2O), 5.15 (dd, 2JHH = 15.0, 3JHP = (5.0, 1 H, CH2O), 6.81 (t, 3JHH = 6.6, 1 H, CHPh), 7.16-7.20 (m, 4 H, CHPh), 7.27 (t, 3JHH = 7.2, 1 H, CHPh), 7.36 (t, 3JHH = 7.8, 1 H, CHPh), 7.39-7.48 (m, ' 10 H, CHPh), 7.55 (d, 3JHH = 7.2, 1 H, CHPh), 7.74 (d, 3JHH = 7.8, 1 H, CHPh), 8.08-8.12 (m, 4 H, CHPh), 8.16 (d, 3JHH = 7i, 2 H, CHPh), 8.652 (d, 3JHH = 4.8, 1 H, Ar.), 8.86 (d, 3JHH = 4.8, 1 H, Ar.), 8.89 (d, 3JHH = 4.8, 1 H, Ar.), 8.90 (d, 3JHH = 4.8, 1 H, Ar.), 8.904 (d, 3JHH = 5.4, 1 H, Ar.), 8.913 (d, 3JHH = ' 5.4, 1 H, Ar.), 9.56 (s, 1H, OCH2CCH). 13C NMR (150.9 MHHz, C6D6, 27 °C) SC ppm: 26.0 (d, 3JCP = 3.8, C(7)), 31.8 (s, C(6)), 48.3 (d, 2JCP = 38.5, C(8)), 54.9 (d, 2JCP = 7.5, C(4)), 60.7 (d, 2JCP = 5.9, CH2O)P 62.8 (d, 2JCP = 8.9, C(5)C, 115.0 (d, 3JCP = 11.6, C2ip)h), 118.9 (s, CHJ, 119.2 (s, Cat), 119.7 (d, J„ = 1.4,', CHJ, 119.8 (s, CJ, 120.4 (s, CJ, 120.7 (s, CJ, 124.3 (s, CHJ, 124.4 (s, CHJ, 126.5 (s, CHJ, 126.56 (s, CHJ, 126.6 (s, CHJ, 126.63 (s, CHJ, 127.0 (s, CHJ, 127.4 (s, CHJ, 127.5 (s, CHJ, 127.6 (s, CHJ, 128.0 (s, CHJ, 129.1 (s, CHJ, 130.4 (very br., CHJ, 131.8 (very br., CHJ, 133.1 (s, CHJ, 133.3 (s, CHJ, 134.5 (s, CHJ, 134.6 (s, CHJ, 142.4 (s, CJ, 142.7 (s, CJ, 142.8 (d, JCP = 2.1, CJ, 146.0 (d, 2JCP = 15.8, CPh). 31P NMR (242.9 MHz, C6D6, 27 °C) SP ppm: 118.3. '
(S a)-4-(4-(10,15,20-Triphenylporphyrin-5-yl)phenoxy) dinaphtho[2,1-d:1',2'-f][1,3,2]dioxaphosphepine (5). Violet powder (0.76 g, yield 80%). [a]D22 = +188.4° (c 1.0, toluene). Found, %: C, 81.55; H, 4.30; N, 5.79. C.H.N OP. Calculated, %:
64 41 4 3
C, 81.34; H, 4.37; N, 5.93. Mass spectra (MALDI TOF/TOF) m/z (%): 945 (100) ([M + H]+), 631 (58) ([C44H30N4O + H]+). 1H NMR (600.13 MHz, CDCl3, 25 °C) SH ppm: -2.73 (br. s, 2 H, NH), 7.347.39 (m, 2 H, Ar.), 7.49-7.55 (m, 4 H, Ar.), 7.61 (d, 3JHH = 8.4, 2 H, Ar.), 7.67 (d, 3JHH = 9.0, 1 H, Ar.), 7.74 (d, 3JHH = 84, 1 H, Ar.), 7.77-7.83 (m, 9 H, Ar.), 8.01 (d, 3JHH = 7.8, 1 H, Ar.), 8.03 (d, 3Jnn = 7.2, 1 H, Ar.), 8.08 (d, 3JHH = 9.0, 1 H, Ar.), 8.11 (d, 3JHH = '9.0, 1 H, Ar.), 8.20 (d, 3JHH = 8.4, 2 H, Ar.), 8.25-8.28 (m, 6 H, Ar.), 8.86-8.91 (m, 8 H, Ar.). 13C NMR (150.9 MHz, CDCl3, 25 °C) SC ppm: 118.8 (d, JCP = 7.6, CHAr), 119.1 (s, CAr), 120.26 (s, Cat), 120.3 (s, Cat), 121.8' (d, Jcp = 1.4, CHJ, 121.9 (s, CHJ, 123.0 (d, JCP = 2.5, CJ, 124.5 (d, JCP = 5.2, CJ, 125.2 (s, CHJ, 125.4 (s, CHj, 126.4 (s, CHJ, 126.5 (s, CHJ, 126.72 (s, CHJ, 126.73 (s, CHJ, 127.1 (s, CHJ, 127.2 (s, CHJ, 127.8 (s, CHJ, 128.48 (s, CHJ, 128.5 (s, CHJ, 130.1 (s, CHJ, 131.2 (very br., CHJ, 131.4 (s, CJ, 131.8 (s, CJ, 132.7 (d, JCp = 1.1, CJ, 133.0 (d, JCP = 1.2, CJ, 134.59 (s, CHJ, 134.61 (s, 'CHJ, 135.7 (s, CHJ, 138.4 (s, CJ, 142.2 (s, CJ, 147.1 (s, 2JCP = 2.3, POC), 147.8 (d, 2JCP = 4.7, POC), 151.7 (d, 2JCP = 6.9, POC). 31P NMR (242.9 MHz,CDCl3, 25 °C) Sp ppm: 143.3.
Catalytic Reactions
Pd-catalyzed allylic sulfonylation of (E)-1,3-diphenylallyl acetate 6 with sodium p-toluene sulfinate. A solution of [Pd(allyl) Cl]2 (1.9 mg, 0.005 mmol) and the appropriate ligand (0.01 mmol or 0.02 mmol) in THF (1.5 ml) was stirred for 40 min. (E)-1,3-Diphenylallyl acetate (0.05 ml, 0.25 mmol) was added and the solution stirred for 15 min, then sodium p-toluene sulfinate (0.089 g, 0.5 mmol) was added and the reaction mixture was stirred for a further 48 h, quenched with brine (3 ml) and extracted with THF (3x2 ml). The organic layer was washed with brine (2x2 ml) and dried over MgSO4. The solvent was evaporated at reduced pressure (40 Torr). Crystallization of the residue from EtOH, followed by desiccation in vacuo (10 Torr, 12 h), has given (E)-1,3-diphenyl-3-tosylprop-1-ene 7a as white crystals.[7071] The enantiomeric excess of 7a was determined by HPLC (Daicel Chiralcel OD-H column, C6H14/i-PrOH = 4/1, 0.5 ml/min, 254 nm, t(R) = 16.3 min, t(S) = 18.5 min).
Pd-catalyzed allylic alkylation of (E)-1,3-diphenylallyl acetate 6 with dimethyl malonate. A solution of [Pd(allyl)Cl]2 (1.9 mg, 0.005 mmol) and the appropriate ligand (0.01 mmol or 0.02 mmol) in the appropriate solvent (1.5 ml) was stirred for 40 min. (E)-1,3-Diphenylallyl acetate (0.05 ml, 0.25 mmol) was added, and the solution was stirred for 15 min. Dimethyl malonate (0.05 ml, 0.44 mmol), BSA (0.11 ml, 0.44 mmol) and potassium acetate (0.002 g) were added. The reaction mixture was stirred for 48 h, diluted with CH2Cl2 or THF (2 ml) and filtered through a thin layer of silica gel. The filtrate was evaporated at reduced pressure (40 Torr) and dried in vacuo (10 Torr, 12 h) affording a residue containing (E)-dimethyl 2-(1,3-diphenylallyl)malonate 7b.[7273] In order to evaluate ee and conversion, the obtained residue was dissolved in an appropriate eluent mixture (8 ml) and a sample was taken for HPLC analysis (Daicel Chiralcel OD-H column, C6H14/i-PrOH = 99/1, 0.3 ml/min, 254 nm, t(R) = 28.0 min, t(S) = 29.3 min).
Pd-catalyzed allylic amination of (E)-1,3-diphenylallyl acetate 6 with pyrrolidine. A solution of [Pd(allyl)Cl]2 (1.9 mg, 0.005 mmol) and the appropriate ligand (0.01 mmol or 0.02 mmol) in the appropriate solvent (1.5 ml) was stirred for 40 min. (E)-1,3-Diphenylallyl acetate (0.05 ml, 0.25 mmol) was added and the solution was stirred for 15 min, then freshly distilled pyrrolidine (0.06 ml, 0.75 mmol) was added. The reaction mixture was stirred for 48 h, diluted with CH2Cl2 or THF (2 ml) and filtered through a thin layer of silica gel. The filtrate was evaporated at reduced pressure (40 Torr) and dried in vacuo (10 Torr, 12 h) affording a residue containing (E)-1-(1,3-diphenylallyl)pyrrolidine 7c.[7475] In order to evaluate ee and conversion, the obtained residue was dissolved in an appropriate eluent mixture (8 ml) and a sample was taken for HPLC analysis (Daicel Chiralcel OD-H column, C6H14/i-
PrOH/HN(Et)2 = 200/1/0.1, 0.9 ml/min, 254 nm, t(R) = 5.0 min, t(S) = 6.1 min).
Pd-catalyzed allylic alkylation of cinnamyl acetate 8 with ethyl 2-oxocyclohexane-1-carboxylate 9. A solution of [Pd(allyl) Cl]2 (1.9 mg, 0.005 mmol) and the appropriate ligand (0.01 mmol or 0.02 mmol) in the appropriate solvent (1.5 ml) was stirred for 40 min. Cinnamyl acetate (0.04 ml, 0.25 mmol) was added, and the solution was stirred for 15 min. Ethyl 2-oxocyclohexane-1-carboxylate (0.06 ml, 0.375 mmol), BSA (0.25 ml, 1 mmol) and zinc acetate (0.005 g) were added. The reaction mixture was stirred for 48 h, diluted with CH2Cl2 or toluene (2 ml) and filtered through a thin layer of silica gel. The filtrate was evaporated at reduced pressure (40 Torr) and dried in vacuo (10 Torr, 12 h) affording a residue containing ethyl 1-cinnamyl-2-oxocyclohexanecarboxylate 10.[53] In order to evaluate ee and conversion, the obtained residue was dissolved in an appropriate eluent mixture (8 ml) and a sample was taken for HPLC analysis (Kromasil 5-CelluCoat, C6H14/i-PrOH = 95/5, 0.4 ml/min, 254 nm, t(R) = 14.3 min, t(S) = 16.4 min).
Acknowledgements. We acknowledge the financial support from the Russian Science Foundation (Grant No. 14-1301383).
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Received 25.06.2015 Accepted 03.08.2015
