Download PDF
Synthesis 2014; 46(05): 653-659
DOI: 10.1055/s-0033-1340497
paper
© Georg Thieme Verlag Stuttgart · New York

Synthesis of Functional Tripodal Phosphines with Amino and Ether Groups by the Hydrophosphination of Trivinyl Ethers with Secondary Phosphines

Ludmila A. Oparina
A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, 1 Favorsky Str., 664033 Irkutsk, Russian Federation   Fax: +7(395)2419346   Email: boris_trofimov@irioch.irk.ru
,
Nina K. Gusarova
A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, 1 Favorsky Str., 664033 Irkutsk, Russian Federation   Fax: +7(395)2419346   Email: boris_trofimov@irioch.irk.ru
,
Oksana V. Vysotskaya
A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, 1 Favorsky Str., 664033 Irkutsk, Russian Federation   Fax: +7(395)2419346   Email: boris_trofimov@irioch.irk.ru
,
Alexander V. Artem’ev
A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, 1 Favorsky Str., 664033 Irkutsk, Russian Federation   Fax: +7(395)2419346   Email: boris_trofimov@irioch.irk.ru
,
Nikita A. Kolyvanov
A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, 1 Favorsky Str., 664033 Irkutsk, Russian Federation   Fax: +7(395)2419346   Email: boris_trofimov@irioch.irk.ru
,
Boris A. Trofimov*
A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, 1 Favorsky Str., 664033 Irkutsk, Russian Federation   Fax: +7(395)2419346   Email: boris_trofimov@irioch.irk.ru
› Author Affiliations
Further Information

Publication History

Received: 17 October 2013

Accepted after revision: 09 December 2013

Publication Date:
08 January 2014 (online)

 
 PDF Download Permissions and Reprints All articles of this category


Abstract

A one-pot, atom-economic, metal- and halogen-free synthesis of functional triphosphines with nitrogen and (or) oxygen atoms­ as additional weaker coordinating sites (new hemilabile ligands) through exhaustive addition of secondary phosphines to available trivinyl ethers of aminotriols and triols has been developed. The reaction proceeds under free-radical conditions (UV irradiation or AIBN, with 3:1 reactant molar ratio) to give chemo- and regioselectively anti-Markovnikov triadducts to all three vinyloxy groups in good to excellent yields.


#

Key words

addition - alkenes - radical reaction - ligands - phosphorylation

Tripodal multidentate phosphines exhibit rich and diverse coordination chemistry and, as such, they have found an integral place in inorganic and organometallic chemistry.[1] [2] [3] Among these phosphines, 1,1,1-tris(diphenylphosphinomethyl)ethane (triphos) is a versatile ligand that can be used with transition metals in a variety of oxidation states.[2] Its complexes have been applied in the area of catalysis, for example in hydrogenation of esters,[4] alkenes[5] and other substrates.[6] [7] Tripodal terdentate phosphines act as ligands in Ru-catalyzed C–O bond cleavage in lignin[8] and dehydrogenation of formic acid (as potential hydrogen storage compound).[9] In addition, these ligands are found to be active stabilizers for noble metal nanoparticles having a small core diameter (< 4 nm) and narrow size distribution.[10] [11] Such nanoparticles show good to excellent catalytic activities for various synthetically important C–C coupling reactions, namely Suzuki, Heck, and Sonogashira, which are widely used in organic synthesis.[11]

Over the last decades, research interest has increasingly focused on polydentate ligands with phosphorus and other donor atoms such as oxygen and nitrogen (P,O-,[12] P,N-,[13] and P,N,O-ligands[14]). In these compounds, the metal center is bounded by phosphorus atom, and weak interactions with the other heteroatom (N or O) ensures additional stabilization of the complexes (hemilable ligands).[14] However, the synthesis of such polydentate ligands presents some difficulties. To our knowledge, functional triphosphines containing amino and ether groups have not been yet described. One of the most straightforward and promising strategies through which to achieve the synthesis of these ligands might be the exhaustive addition of secondary phosphines to trivinyl ethers of triols.

Here, we report on the radical addition of available secondary phosphines 1–6, which are easily prepared from elemental phosphorus and aryl(or hetaryl)ethenes,[15] to trivinyl ethers of aminotriols 7, 8 and triols 9–11. These trivinyl ethers were chosen because they are efficiently prepared by vinylation of the corresponding triols with acetylene in superbases of the type KOH/dimethyl sulfoxide (DMSO).[16]

We have found that bis(aralkyl)phosphines 1 and 2 can be exhaustively added to N,N,N-tris[2-(vinyloxy)ethyl]amine (7) in the presence of a radical initiator (AIBN, 65 °C, 60 h, 1,4-dioxane, argon, the 3:1 reactant molar ratio) in an anti-Markovnikov manner to afford triphosphines 12а and 12b, respectively, with amino and ether groups, in almost quantitative yields (Scheme [1]). Notably, the reaction proceeds chemo- and regioselectively, and none of the corresponding mono-, di- or Markovnikov adducts, or cyclization or telomerization products were observed (1H and 31P NMR analysis) under these conditions.

Zoom Image
Scheme 1 Exhaustive free-radical addition of secondary phosphines 1 and 2 to N,N,N-tris[2-(vinyloxy)ethyl]amine (7)

Under similar conditions (AIBN, 75 °C, 72 h, benzene, argon), bis(aralkyl)phosphines 1 and 3 react with the trivinyl ether of aminotriol 8 at a 3:1 molar ratio to give anti-Markovnikov triadducts 13а and 13b, respectively, in 92 and 86% yield (Scheme [2]).

Zoom Image
Scheme 2 Synthesis of triphosphines with NH2 and ether groups from secondary phosphines 1 and 3, and the trivinyl ether of amino­triol 8

The efficacy and generality of the elaborated strategy was confirmed by the synthesis of functional triphosphines with ether groups by the exhaustive free-radical addition of secondary phosphines to trivinyl ethers of triols 9–11. Indeed, the free-radical initiation (UV irradiation or AIBN) proved to be effective for the full hydrophosphination of glycerol trivinyl ether 9 with a diverse range of secondary phosphines 1 and 4–6, bearing aralkyl, hetaralkyl, and phenyl substituents, to afford anti-Markovnikov triadducts 14a–d in 80–90% yield (Table [1]). The reaction time was 9 hours in the case of UV irradiation (Table [1], entries 1 and 3), and 24–53 hours when AIBN was employed (Table [1], entries 2, 4, and 5).

Table 1 Exhaustive Free-Radical Addition of Secondary Phosphines 1 and 4–6 to the Trivinyl Ether of Glycerol 9 a

Entry

Phosphine

R

Initiator

Solvent

Temp (°C)

Time (h)

14

Yield (%)b

1

1

(CH2)2Ph

UV

1,4-dioxane

40с

 9

14a

90

2

1

(CH2)2Ph

AIBN

none

65

24

14a

87

3

4

UV

1,4-dioxane

40с

9

14b

88

4

5

AIBN

none

65

53

14c

80

5

6

Ph

AIBN

none

65

48

14d

90

a Reaction conditions: phosphine (3 equiv.), 9 (1 equiv), argon, UV irradiation (200 W Hg arc lamp) or AIBN (2 wt% of total reactant mass).

b Isolated yield.

c Heating caused by UV lamp.

Triphosphines 15a–d with ether groups have likewise been synthesized in high yields by the reaction of trivinyl ethers of triols (10 or 11) with bis(aralkyl)phosphines 1 or 3 in the presence of AIBN (Table [2]). A preliminary application of this strategy was reported with examples of divinyl ethers of diols[17] and the tetravinyl ether of pentaerithritol.[18]

The high chemo- and regioselectivity of the hydrophos­phination found deserves special consideration. Indeed, as noted above, neither expected cyclizations nor oligomerizations were discernible in this hydrophosphination. However, in contrast to these results, it was reported that free-radical hydrophosphorylation of divinyl ethers of dioles with dialkylphosphites under similar conditions (AIBN, 67–70 °C) resulted in the formation of cyclic products (ca. 50% yield), and macrocyclic and linear phosphorus-containing telomeres.[19] Furthermore,[20] free-radical addition of diethyl thiophosphite to diallyl ether (AIBN, 60 °C, THF) proceeds as exclusive cyclization to yield O,O-diethyl (4-methyltetrahydro-3-furanyl)methylthiophosphonate. This occurs because initial intermediate radical-adducts preferentially attack the neighboring double bonds instead of abstracting a hydrogen radical from the phosphite molecule. The astonishing full inhibition of the side cyclization and telomerization reactions during the hydrophosphination with secondary phosphines may be rationalized in terms of the spin exchange between the radical center and lone electron pair of the phosphine moiety in the initial intermediate radical-adduct A (Scheme [3]). Such a through-space interaction may preclude attack of the intermediate A on the neighboring double bonds, instead of abstracting the hydrogen atom from the P–H bond. Since dialkylphosphites do not have the lone electron pair on the phosphorus atom, they cannot participate in the above spin-exchange. Additionally, the P–H bond homolization energy in dialkylphosphites is much higher than that of phosphines (365 and 319 kJ/mol, respectively).[21] Therefore, in case of hydrophosphination, transfer of the hydrogen atom from another phosphine molecule on radical A (Scheme [3]) appears to be more favorable than intramolecular cyclization of the latter.

Table 2 Exhaustive Free-Radical Addition of Secondary Phosphines 1 and 3 to Trivinyl Ethers 10 and 11 a

Entry

Phosphine

R1

Trivinyl ether

R2

Adduct

Yield (%)b

1

1

(CH2)2Ph

10

Me

15a

88

2

1

(CH2)2Ph

11

Et

15b

82

3

3

10

Me

15c

92

4

3

11

Et

15d

90

a Reaction conditions: phosphine (3 equiv.), 10/11 (equiv.), AIBN (2 wt% of the total reactant mass), 75 °C, 72 h, argon.

b Isolated yield.

Zoom Image
Scheme 3 A through-space stabilization within radical-adduct A

Trialkyl- and tris(aralkyl)phosphines are known to be readily oxidized to the corresponding phosphine oxides on exposure to air.[13c] [22] Surprisingly, triphosphines 12–15 are more resistant to air oxidation. For example, after storage of triphosphine 14a in an open vessel at room temperature for one month, only traces of its oxide were detected (31P NMR analysis). In contrast, triphoshines are smoothly oxidized by aqueous H2O2 (r.t., 3 h, acetone) to give the corresponding triphosphine oxides quantitatively (exemplified by oxidation of triphosphine 14d to triphosphine oxide 16; Scheme [4]).

Zoom Image
Scheme 4 Oxidation of trisphosphine 14d

Clearly, the stability of the synthesized triphoshines towards air oxidation is advantageous for their handling and applications, particularly as ligands. Moreover, these tripodal phosphines of hemilabile character will likely be used in the design of new metal complexes with diverse and tunable catalytic activity. These compounds are also prospective synthetic intermediates. For instance, triphosphine 12a easily reacts (r.t., 1 h) with iodomethane to give salt 17 in 97% yield (Scheme [5]).

Zoom Image
Scheme 5 Exhaustive quaternization of triphosphine 12a [R = Ph(CH2)2]

Over the last years, such phosphonium salts have been considered as very promising alternatives to imidazolium-based ionic liquids due to the superior thermal stability of phosphonium analogues and their inertness in basic reaction media.[23]

The novel tripodal phosphines 12–15 have been fully characterized by multinuclear (1H, 13C and 31P) NMR and IR spectroscopy; their composition was also confirmed by elemental analysis data.

In summary, a novel group of functional triphosphines bearing amino and (or) ether groups has been synthesized through exhaustive chemo- and regioselective free-radical addition of secondary phosphines to trivinyl ethers of triols, thereby demonstrating the generality and wide substrate scope of this strategy for the synthesis of tripodal phosphines with extra hemilabile sites. These triphosphines are prospective polydentate ligands that can be used in the design of multipurpose metal complexes and reactive building blocks for organic synthesis, and the primary amino group in triphosphines 13a and 13b secures almost unlimited possibilities for the synthesis of a wide range of novel tripodal phosphines with hemilabile sites.

All reactions were carried out under an argon atmosphere. All solvents were dried and purified according to standard procedures. Secondary phosphines 1–5 were prepared from the corresponding styrenes and 2-vinylfuran and red phosphorus as previously described.[17] Diphenylphosphine (6) was employed as purchased (Aldrich). Trivinyl ethers 7–11 were prepared according to a published method.[18] 1H, 13C, 31P NMR spectra were recorded with Bruker DPX 400 or Bruker AV-400 spectrometers (400.13, 100.62, and 161.98 MHz, respectively) at ambient temperature for CDCl3 solutions. Chemical shifts are reported in δ units (ppm) relative to CDCl3 (1H, 13C) as internal standard or H3PO4 (31P) as external standard. FTIR spectra were recorded with a Bruker Vertex 70 spectrometer. Microanalyses were performed with a Flash EA 1112 Series elemental analyzer. Melting points were recorded with a Stuart melting-point apparatus and are uncorrected.


#

Synthesis of Triphosphines 12–15; General Procedure

Method A: A solution of PH-addend 1 or 4 (0.9 mmol) and trivinyl ether 9 (0.3 mmol) in 1,4-dioxane (0.5 mL) was irradiated (200 W Hg arc lamp) in a quartz ampoule (the reaction time is given in Table [1]).

Method B: A solution of PH-addend 1–6 (0.9 mmol) and trivinyl ether 7–11 (0.3 mmol) either with solvent (0.5 mL) or without solvent, in the presence of AIBN (2 wt% of the total mass of reactants) was stirred at 65–75 °C in a sealed ampoule for the given reaction time (Table [1, ]Table [2], and Scheme [1]).

The reaction was monitored by 31P NMR spectroscopy following the disappearance of the peaks of the starting PH-addendes (the –82 to –69 ppm region for phosphines 1–5, and the –39 ppm region for phosphine 7) and appearance of new peaks in the –32 to –20 ppm region corresponding to triphosphines 12–15. The reaction mixture was dissolved in Et2O (3 mL), and passed through a layer of Al2O3 (activity level II, 0.5 cm), and the latter was additionally washed with n-hexane–Et2O (1:1, 3 mL). The solvents were removed under reduced pressure to give triphosphines 12–15.


#

N,N,N-Tris[2-(diphenethylphosphino)ethoxyethyl]amine (12a)

Yield: 275 mg (96%); colorless oil.

IR (KBr): 752 (P–C) cm–1.

1H NMR (400.13 MHz, CDCl3): δ = 1.79–1.83 (m, 18 H, PCH2), 2.75–2.83 (m, 18 H, PhCH2, NCH2), 3.52–3.64 (m, 12 H, OCH2), 7.22–7.33 (m, 30 H, Ph).

13C NMR (100.62 MHz, CDCl3): δ = 27.8 (d, 2 J P–C = 14.6 Hz, PhСH2), 29.4 (d, 1 J P–C = 14.0 Hz, PCH2CH2O), 32.3 (d, 1 J P–C = 14.6 Hz, PCH2), 54.8 (NCH2), 68.9 (d, 2 J P–C = 20.1 Hz, CH2O), 69.5 (CH2O), 126.0 (p-C in Ph), 128.2 (o-C in Ph), 128.5 (m-C in Ph), 142.8 (d, 3 J P–C = 10.5 Hz, ipso-C in Ph).

31P NMR (161.98 MHz, CDCl3): δ = –32.3.

Anal. Сalcd for C60H78NO3P3: С, 75.52; Н, 8.24; N, 1.47; Р, 9.74. Found: С, 75.58; Н, 8.33; N, 1.55; Р, 9.86.


#

N,N,N-Tris[2-(bis[4-(tert-butyl)phenylethyl]phosphino)ethoxyethyl]amine (12b)

Yield: 364 mg (94%); colorless oil.

IR (KBr): 771 (P–C) cm–1.

1H NMR (400.13 MHz, CDCl3): δ = 1.34 (s, 54 H, 18 × Me), 1.77–1.85 (m, 18 H, PCH2), 2.73–2.84 (m, 18 H, ArCH2, NCH2), 3.53–3.63 (m, 12 H, OCH2), 7.14–7.35 (m, 24 H, Ar).

13C NMR (100.62 MHz, CDCl3): δ = 27.6 (d, 2 J P–C = 14.7 Hz, ArСH2), 29.1 (d, 1 J P–C = 13.8 Hz, PCH2CH2O), 31.3 (18 × Me), 31.5 (d, 1 J P–C = 14.7 Hz, PCH2), 54.6 (NCH2), 68.8 (d, 2 J P–C = 20.7 Hz, CH2O), 69.4 (CH2O), 77.9 (C in t-Bu), 125.4 (C2,6 in Ar), 127.6 (C3,5 in Ar), 139.6 (d, 3 J P–C = 10.8 Hz, C1 in Ar), 148.6 (C4 in Ar).

31P NMR (161.98 MHz, CDCl3): δ = –31.7.

Anal. Сalcd for C84H126NO3P3: С, 78.16; Н, 9.84; N, 1.09; Р, 7.20. Found: С, 78.35; Н, 9.42; N, 1.14; Р, 7.47.


#

1,1,1-Tris[2-(diphenethylphosphino)ethoxymethyl]methylamine (13a)

Yield: 256 mg (92%); colorless oil.

IR (KBr): 752 (P–C), 3299, 3379 (N–H) cm–1.

1H NMR (400.13 MHz, CDCl3): δ = 1.74–1.78 (m, 18 H, PCH2), 2.70–2.74 (m, 12 H, PhCH2), 2.91 (s, 2 H, NH2), 3.33 (s, 6 H, CH2O), 3.55–3.60 (m, 6 H, CH2O), 7.18–7.27 (m, 30 H, Ph).

13C NMR (100.62 MHz, CDCl3): δ = 27.3 (d, 2 J P–C = 14.8 Hz, PhСH2), 29.0 (d, 1 J P–C = 14.0 Hz, PCH2CH2O), 32.0 (d, 1 J P–C = 14.6 Hz, PCH2), 55.6 (CNH2), 68.1 (d, 2 J P–C = 18.8 Hz, CH2O), 72.8 (OCH2C), 125.71 (p-C in Ph), 127.8 (o-C in Ph), 128.2 (m-C in Ph), 142.5 (d, 3 J P–C = 10.7 Hz, ipso-C in Ph).

31P NMR (161.98 MHz, CDCl3): δ = –31.7.

Anal. Сalcd for C58H74NO3P3: С, 75.22; Н, 8.05; N, 1.51; Р, 10.03. Found: С, 75.35; Н, 8.27; N, 1.63; Р, 9.87.


#

1,1,1-Tris[2-(bis[4-(tert-butoxy)phenylethyl]phosphino)ethoxymethyl]methylamine (13b)

Yield: 351 mg (86%); colorless oil.

IR (KBr): 756 (P–C), 3292, 3349 (N–H) cm–1.

1H NMR (400.13 MHz, CDCl3): δ = 1.33 (s, 54 H, 18 × Me), 1.73–1.79 (m, 18 H, PCH2), 2.69–2.73 (m, 12 H, ArCH2), 3.46–3.65 (m, 14 H, CH2O, NH2), 6.89–7.09 (m, 24 H, ArH).

13C NMR (100.62 MHz, CDCl3): δ = 27.6 (d, 2 J P–C = 14.7 Hz, ArСH2), 28.8 (18 Me), 29.3 (d, 1 J P–C = 13.4 Hz, PCH2CH2O), 31.6 (d, 1 J P–C = 14.7 Hz, PCH2), 55.8 (CNH2), 69.4 (d, 2 J P–C = 18.5 Hz, CH2O), 72.9 (CH2O), 78.1 (C in t-BuO), 124.1 (C2,6 in Ar), 128.3 (C3,5 in Ar), 137.6 (d, 3 J P–C = 10.4 Hz, C1 in Ar), 153.4 (C4 in Ar).

31P NMR (161.98 MHz, CDCl3): δ = –31.5.

Anal. Сalcd for C82H122NO9P3: С, 72.48; Н, 9.05; N, 1.03; Р, 6.84. Found: С, 72.65; Н, 9.12; N, 1.17; Р, 6.77.


#

1,2,3-Tris(2-{diphenethylphosphino}ethoxy)propane (14a)

Yield: 242 mg (90%) (method A), 234 mg (87%) (method B); colorless oil.

IR (KBr): 752 (P–C) cm–1.

1H NMR (400.13 MHz, CDCl3): δ = 1.73–1.77 (m, 18 H, PCH2), 2.69–2.75 (m, 12 H, PhCH2), 3.45–3.62 (m, 10 H, PCH2 CH2O, CH2O), 3.75 (m, 1 H, CHO), 7.15–7.28 (m, 30 H, PhH).

13C NMR (100.62 MHz, CDCl3): δ = 27.6 (d, 2 J P–C = 14.6 Hz, PhСH2), 27.9 (d, 2 J P–C = 14.6 Hz, PhСH2), 29.3 (d, 1 J P–C = 13.8 Hz, PCH2), 32.2 (d, 1 J P–C = 14.6 Hz, PCH2), 68.2 (d, 2 J P–C = 20.7 Hz, PCH2 CH2O), 69.3 (d, 2 J P–C = 20.3 Hz, PCH2 CH2O), 70.9 (CH2O), 77.9 (CHO), 125.9 (p-C in Ph), 128.1 (o-C in Ph), 128.4 (m-C in Ph), 142.7 (d, 3 J P–C = 10.4 Hz, ipso-C in Ph).

31P NMR (161.98 MHz, CDCl3): δ = –31.5 (br s).

Anal. Сalcd for C57H71O3P3: С, 76.31; Н, 7.98; Р, 10.36. Found: C, 76.54; Н, 7.80; Р, 10.33.


#

1,2,3-Tris(2-{bis[4-chlorophenethyl]phosphino}ethoxy)propane (14b)

Yield: 291 mg (88%) (method A); colorless oil.

IR (KBr): 651 (P–C) cm–1.

1H NMR (400.13 MHz, CDCl3): δ = 1.62–1.71 (m, 6 H, PCH 2CH2O), 1.96–2.10 (m, 12 H, PCH2), 2.57–2.67 (m, 4 H, CH2Ar), 2.78–2.94 (m, 8 H, CH2Ar), 3.44–3.54 (m, 5 H, CH2O, CHO), 3.70–3.81 (m, 6 H, PCH2CH 2O), 7.03–7.11 (m, 12 H, H2,6 in Ar), 7.19–7.25 (m, 12 H, H3,5 in Ar).

13C NMR (100.62 MHz, CDCl3): δ = 27.0 (d, 2 J P–C = 15.0 Hz, CH2Ar), 27.3 (d, 2 J P–C = 15.0 Hz, CH2Ar), 29.1 (d, 1 J P–C = 14.2 Hz, PCH2CH2O), 31.5 (d, 1 J P–C = 14.9 Hz, PCH2), 68.2 (d, 2 J P–C = 20.7 Hz, PCH2 CH2O), 69.3 (d, 2 J P–C = 20.3 Hz, PCH2 CH2O), 70.9 (CH2O), 77.9 (CHO), 128.4 (C2,6 in Ar), 128.7 (C3,5 in Ar), 129.4 (C4 in Ar), 140.9 (d, 3 J P–C = 10.0 Hz, C1 in Ar).

31P NMR (161.98 MHz, CDCl3): δ = –31.5 (br s).

Anal. Сalcd for C57H65Cl6O3P3: С, 62.03; Н, 5.94; Cl, 19.27; Р, 8.42. Found: С, 62.21; Н, 5.82; Cl, 19.14; Р, 8.54.


#

1,2,3-Tris(2-{bis[2-(2-furyl)ethyl]phosphino}ethoxy)propane (14c)

Yield: 201 mg (80%) (method B); colorless oil.

IR (KBr): 731 (P–C) cm–1.

1H NMR (400.13 MHz, CDCl3): δ = 1.70–1.78 (m, 18 H, PCH2), 2.71–2.77 (m, 12 H, CH 2Fur), 3.44–3.76 (m, 11 H, CH2O, CHO), 5.98 (br s, 6 H, H3 in Fur), 6.25 (br s, 6 H, H4 in Fur), 7.27 (br s, 6 H, H5 in Fur).

13C NMR (100.62 MHz, CDCl3): δ = 20.4 (CH2Fur), 24.6 (d, 1 J P–C = 13.6 Hz, PCH2), 25.4 (d, 1 J P–C = 16.5 Hz, PCH2), 27.4 (d, 2 J P–C = 14.6 Hz, PCH2CH2O), 27.7 (d, 2 J P–C = 13.2 Hz, PCH2CH2O), 68.0 (d, 2 J P–C = 22.8 Hz, PCH2 CH2O), 69.2 (d, 2 J P–C = 19.7 Hz, PCH2 CH2O), 70.9 (CH2O), 77.9 (CHO), 104.9 (C3 in Fur), 110.1 (C4 in Fur), 140.9 (C5 in Fur), 155.9 (d, 3 J P–C = 11.3 Hz, C2 in Fur).

31P NMR (161.98 MHz, CDCl3): δ = –31.9 (br s).

Anal. Сalcd for C45H59O9P3: С, 64.58; Н, 7.11; Р, 11.10. Found: С, 64.69; Н, 7.30; Р, 11.27.


#

1,2,3-Tris[2-(diphenylphosphino)ethoxy]propane (14d)

Yield: 197 mg (90%) (method B); colorless oil.

IR (KBr): 740 (P–C) cm–1.

1H NMR (400.13 MHz, CDCl3): δ = 2.26–2.32 (m, 6 H, PCH2), 3.27–3.65 (m, 11 H, CH2O, CHO), 7.23–7.37 (m, 30 H, Ph).

13C NMR (100.62 MHz, CDCl3): δ = 28.8 (d, 1 J P–C = 13.0 Hz, PCH2), 29.2 (d, 1 J P–C = 13.1 Hz, PCH2), 67.6 (d, 2 J P–C = 25.3 Hz, PCH2 CH2O), 68.7 (d, 2 J P–C = 24.5 Hz, PCH2 CH2O), 70.7 (CH2O), 77.8 (CHO), 128.4 (p-C in Ph), 128.5 (d, 2 J P–C = 13.0 Hz, o-C in Ph), 132.7 (d, 3 J P–C = 19.3 Hz, m-C in Ph), 138.4 (d, 1 J P–C = 13.0 Hz, ipso-C in Ph).

31P NMR (161.98 MHz, CDCl3): δ = –20.9.

Anal. Сalcd for C45H47O3P3: С, 74.16; Н, 6.50; Р, 12.75. Found: С, 74.25; Н, 6.36; Р, 12.88.


#

1,1,1-Tris[2-(diphenethylphosphino)ethoxymethyl]ethane (15a)

Yield: 244 mg (88%); colorless oil.

IR (KBr): 753 (P–C) cm–1.

1H NMR (400.13 MHz, CDCl3): δ = 0.95 (s, 3 H, Me), 1.71–1.78 (m, 18 H, PCH2), 2.68–2.72 (m, 12 H, PhCH2), 3.25 (s, 6 H, CH2O), 3.52–3.56 (m, 6 H, PCH2CH 2O), 7.23–7.41 (m, 30 H, Ph).

13C NMR (100.62 MHz, CDCl3): δ = 17.6 (Me), 27.5 (d, 1 J P–C = 14.0 Hz, PhCH2), 29.2 (d, 1 J P–C = 13.9 Hz, PCH2CH2O,), 32.2 (d, 1 J P–C = 14.5 Hz, PCH2), 40.8 (C), 69.4 (d, 2 J P–C = 18.9 Hz, PCH2 CH2O), 73.6 (CH2O), 125.9 (p-C in Ph), 128.0 (o-C in Ph), 128.4 (m-C in Ph), 142.8 (d, 3 J P–C = 11.1 Hz, ipso-C in Ph).

31P NMR (161.98 MHz, CDCl3): δ = –31.5.

Anal. Сalcd for C59H75O3P3: С, 76.60; Н, 8.17; Р, 10.04. Found: С, 76.54; Н, 8.08; Р, 10.21.


#

1,1,1-Tris[2-(diphenethylphosphino)ethoxymethyl]propane (15b)

Yield: 231 mg (82%); colorless oil.

IR (KBr): 752 (P–C) cm–1.

1H NMR (400.13 MHz, CDCl3): δ = 0.87 (t, 3 J H–H = 7.4 Hz, 3 H, Me), 1.42 (q, 3 J H–H = 7.6 Hz, 2 H, CH 2Me), 1.77–1.82 (m, 18 H, PCH2), 2.73–2.79 (m, 12 H, PhCH2), 3.30 (s, 6 H, CH2O), 3.54–3.60 (m, 6 H, PCH2CH 2O), 7.19–7.32 (m, 30 H, Ph).

13C NMR (100.62 MHz, CDCl3): δ = 7.8 (Me), 23.1 (СH2), 27.5 (d, 1 J P–C = 14.5 Hz, PhCH2), 29.3 (d, 1 J P–C = 13.9 Hz, PCH2CH2O), 32.3 (d, 1 J P–C = 14.5 Hz, PCH2), 43.1 (C), 69.3 (d, 2 J P–C = 18.5 Hz, CH2O), 71.4 (CH2O), 125.9 (p-C in Ph), 128.1 (o-C in Ph), 128.4 (m-C in Ph), 142.8 (d, 3 J P–C = 10.8 Hz, ipso-C in Ph).

31P NMR (161.98 MHz, CDCl3): δ = –31.4.

Anal. Сalcd for C60H77O3P3: С, 76.73; Н, 8.26; Р, 9.89. Found: С, 76.69; Н, 8.30; Р, 9.47.


#

1,1,1-Tris[2-bis[4-(tert-butoxy)phenethyl]phosphinoethoxymethyl]ethane (15c)

Yield: 375 mg (92%); colorless oil.

IR (KBr): 756 (P–C) cm–1.

1H NMR (400.13 MHz, CDCl3): δ = 0.93 (s, 3 H, CH3), 1.32 (s, 54 H, 18 Me), 1.74–1.78 (m, 18 H, PCH2), 2.67–2.71 (m, 12 H, ArCH2), 3.27 (s, 6 H, CH2O), 3.52–3.58 (m, 6 H, PCH2CH 2O), 6.89–7.08 (m, 24 H, Ar).

13C NMR (100.62 MHz, CDCl3): δ = 17.6 (CH3), 27.5 (d, 1 J PC = 13.8 Hz, ArCH2), 28.8 (18 Me), 29.3 (d, 1 J PC = 13.4 Hz, PCH2CH2O), 31.6 (d, 1 J PC = 14.7 Hz, PCH2), 40.8 (CMe), 69.4 (d, 2 J PC = 19.0 Hz, CH2O), 73.7 (CH2O), 78.1 (C in t-BuO), 124.1 (C2,6 in Ar), 128.4 (C3,5 in Ar), 137.7 (d, 3 J PC = 10.8 Hz, C1 in Ar), 153.4 (C4 in Ar).

31P NMR (161.98 MHz, CDCl3): δ = –31.3.

Anal. Сalcd for C83H123O9P3: С, 73.42; Н, 9.13; Р, 6.84. Found: С, 73.70; Н, 9.26; Р, 6.72.


#

1,1,1-Tris[2-bis[4-(tert-butoxy)phenethyl]phosphinoethoxymethyl]propane (15d)

Yield: 370 mg (90%); colorless oil.

IR (KBr): 756 (P–C) cm–1.

1H NMR (400.13 MHz, CDCl3): δ = 0.69 (t, 3 J = 7.5 Hz, 3 H, Me), 1.18 (s, 54 H, 18 × Me), 1.25 (q, 3 J H–H = 7.5 Hz, 2 H, CH 2Me), 1.58–1.64 (m, 18 H, PCH2), 2.53–2.59 (m, 12 H, ArCH2), 3.137 (s, 6 H, CH2O), 3.38–3.44 (m, 6 H, PCH2CH 2O), 6.74–6.94 (m, 24 H, Ar).

13C NMR (100.62 MHz, CDCl3): δ = 7.8 (Me), 23.0 (СH2), 27.5 (d, 2 J P–C = 14.2 Hz, ArСH2), 28.8 (18 Me), 29.3 (d, 1 J P–C = 13.8 Hz, PCH2CH2O), 31.6 (d, 1 J P–C = 14.7 Hz, PCH2), 43.0 (CEt), 69.3 (d, 2 J P–C = 18.5 Hz, CH2O), 71.3 (CH2O), 78.0 (C in t-BuO), 124.1 (C2,6 in Ar), 128.3 (C3,5 in Ar), 137.7 (d, 3 J P–C = 11.2 Hz, C1 in Ar), 153.4 (C4 in Ar).

31P NMR (161.98 MHz, CDCl3): δ = –31.2.

Anal. Сalcd for C84H125O9P3: С, 73.55; Н, 9.18; Р, 6.77. Found: С, 73.63; Н, 9.30; Р, 6.84.


#

Oxidation of Triphosphine 14d with H2O2 (Scheme [4]); Synthesis of 1,2,3-Tris[2-(diphenylphosphinyl)ethoxy]propane (16)

To a solution of triphosphine 14d (146 mg, 0.2 mmol) in acetone (5 mL), a 33% aqueous solution of H2O2 (1 mL) was added dropwise. The reaction mixture was stirred at 23–25 °C for 3 h, then solvents were evaporated in vacuum and the residue was reprecipitated from chloroform to hexane and dried in vacuum to give triphosphine oxide 16.

Yield: 149 mg (96%); white resin.

IR (KBr): 1173 (P=O), 751 (P–C) cm–1.

1H NMR (400.13 MHz, CDCl3): δ = 2.51–2.58 (m, 6 H, PCH2), 3.07–3.19 (m, 5 H, CH2O), 3.60–3.77 (m, 6 H, CHO), 7.41–7.76 (m, 30 H, Ph).

13C NMR (100.62 MHz, CDCl3): δ = 30.5 (d, 1 J P–C = 70.7 Hz, PCH2), 30.9 (d, 1 J P–C = 70.3 Hz, PCH2), 63.5, 64.6 (PCH2 CH2O), 70.4 (CH2O), 77.5 (CHO), 128.6 (d, 3 J P–C = 11.6 Hz, m-C in Ph), 130.7 (d, 2 J P–C = 9.5 Hz, o-C in Ph), 131.8 (p-C in Ph), 132.8 (d, 1 J P–C = 100.4 Hz, ipso-C in Ph).

31P NMR (161.98 MHz, CDCl3): δ = 31.04, 31.15.

Anal. Сalcd for C45H47O6P3: С, 69.58; Н, 6.10; Р, 11.96. Found: С, 69.35; Н, 6.15; Р, 12.09.


#

Exhaustive Quaternization of Triphosphine 12a (Scheme [5]); Synthesis of Methyl-N,N,N-tris{2-[methyl-bis(phenyleth­yl)phosphonio]ethoxyethyl}ammonium Tetraiodide (17)

A solution of triphosphine 12a (204 mg, 0.21 mmol) and MeI (1 mL) in Et2O (2 mL) was stirred under an argon atmosphere at 23–25 °C for 1 h. The solvent and excess MeI were removed in vacuum, the residue was ground in hexane (7 mL), and the hexane was decanted. The white powder formed was washed with hexane (10 mL) and dried in vacuum (1 Torr, 35–40 °C) to afford salt 17.

Yield: 310 mg (97%); white powder; mp 68 °C.

1H NMR (400.13 MHz, CDCl3): δ = 1.95–2.28 (m, 18 H, PCH2), 2.08 (d, 1 J PH = 11.7 Hz, 9 H, 3 PMe), 2.75–2.90 (m, 18 H, PhCH2, NCH2), 3.30–3.38 (br s, 3 H, NMe), 3.91–4.04 (m, 12 H, OCH2), 7.15–7.30 (m, 30 H, Ph).

31P NMR (161.98 MHz, CDCl3): δ = 32.46.

Anal. Сalcd for C64H90I4NO3P3: C, 50.51; H, 5.96; I, 33.35; N, 0.92; P, 6.11. Found: C, 50.71; H, 5.95; I, 32.82; N, 1.26; P, 6.18.


#
#

Acknowledgment

This work was supported by the Russian Foundation for Basic Research (grant no. 11-03-00286) and the President of the Russian Federation (program for the support of leading scientific schools, grant NSh-1550.2012.3).

Supporting Information

    for this article is available online at http://www.thieme-connect.com.accesdistant.sorbonne-universite.fr/ejournals/toc/synthesis.
  • Supporting Information


   Permissions and Reprints All articles of this category
Zoom Image
Scheme 1 Exhaustive free-radical addition of secondary phosphines 1 and 2 to N,N,N-tris[2-(vinyloxy)ethyl]amine (7)
Zoom Image
Scheme 2 Synthesis of triphosphines with NH2 and ether groups from secondary phosphines 1 and 3, and the trivinyl ether of amino­triol 8
Zoom Image
Scheme 3 A through-space stabilization within radical-adduct A
Zoom Image
Scheme 4 Oxidation of trisphosphine 14d
Zoom Image
Scheme 5 Exhaustive quaternization of triphosphine 12a [R = Ph(CH2)2]