Synthesis of an Acrylate from CO2 and an Alkene
FULL PAPER
ene (2 bar) and CO2 (6 bar) to an overall pressure of 8 bar and then
heated to 25 (1d) or 508C (1a–c, e, and f) and the reaction was studied
by NMR spectroscopy (1H/31P) after 19 (1d) or 72 h (1a–c, e, and f).
(1.74 g, 5.45 mmol) were dissolved in THF (20 mL). The reaction mixture
was cooled to 08C and then acrylic acid (390 mL, 5.70 mmol) was added
slowly. After stirring at 08C for 3 h, the solvent was removed by evapora-
tion and the crude mixture was washed with Et2O (2ꢇ10 mL). Filtration
and drying under vacuum yielded compound 6 as a yellow powder
(2.31 g, 94%). Crystals suitable for X-ray analysis were grown at RT by
slow diffusion of Et2O into a saturated solution in THF. Yellow crystal
(polyhedron); dimensions: 0.23ꢇ0.14ꢇ0.05 mm3; crystal system: mono-
clinic; space group: P21/c; Z=4; a=11.0623(16), b=16.941(3), c=
14.043(2) ꢆ; a=90, b=112.762(3), g=908; V=2426.8(6) ꢆ3; 1=
1.230 gcmÀ3; T=200(2) K; qmax =28.338; radiation: MoKa, l=0.71073 ꢆ;
0.38 w scans with a CCD area detector, covering a whole sphere in recip-
1
Ligand 1a (dppm): Formation of a black precipitate. H NMR (200 MHz,
[D8]THF): d=2.33 (s, 8H; CH2 COD, dppm), 5.35 (s, 4 H; C2H4),
5.50 ppm (s, 4H; CH COD); 31P{1H} NMR (81 MHz, [D8]THF): d=
22 ppm (brs).
Ligand 1b (dppe): 31P NMR spectroscopic yield of 4b: 65%. 1H NMR
(200 MHz, [D8]THF): d=2.07 (m, 4H; CH2 dppe), 2.33 (s, 8H; CH2
COD), 5.35 (s, 4 H; C2H4), 5.50 (s, 4H; CH COD), 6.98 (m, 8H; CH),
7.39 ppm (m, 12H; CH); 31P{1H} NMR (81 MHz, [D8]THF): d=43.9 (s;
4b), 50.9 ppm (s).
Ligand 1c (dppp): 31P NMR spectroscopic yield of 4c: 24%. 1H NMR
(200 MHz, [D8]THF): d=1.70. (m, 4H; CH2 dppp) 2.17 (brs, 2H; CH2
dppe), 2.33 (s, 8H; CH2 COD), 4.96 (s, 4 H; C2H4), 5.50 (s, 4H; CH
COD), 7.05 (m, 2H; CH), 7.24 (m, 10H; CH), 7.51 ppm (m, 8H; CH);
31P{1H} NMR (81 MHz, [D8]THF): d=12.0 (s; 4c), 17.4 (s), 20.8 ppm (s).
Ligand 1d (dtbpm): 31P NMR spectroscopic yield of 2d: 60%; 1d: 40 %.
1H NMR (200 MHz, [D8]THF): d=0.91 (m, 2H; 2d NiCH2), 1.20 (m, 36
H; 1 d CH3), 1.49 (m, 18H; 2d CH3), 1.56 (m, 2, 18H; 1 d, 2d CH2,
CH3), 1.75 (s), 2.12 (s,), 2.33 (s, 8H; CH2 COD), 2.62 (m, 2H; 2d
CH2CO), 3.60 (brs), 4.32 (s) 5.36 (s, 4 H; C2H4), 5.50 ppm (s, 4H; CH
COD); 31P{1H} NMR (81 MHz, [D8]THF): d=16.3 (d, J=22.8 Hz, 2d),
21.8 (s, 1 d), 36.1 ppm (d, J=22.8 Hz, 2 d).
rocal space; reflections: 25344 measured, 6021 unique (RACTHNUTRGNE(UNG int)=0.0325),
5032 observed (I>2s(I)); m=0.94 mmÀ1; min/max transmission=0.81/
0.95; 238 parameters refined; hydrogen atoms were treated by using ap-
propriate riding models, except for H15 (in the carboxy group), which
was refined isotropically; goodness of fit: 1.07 for observed reflections;
final residual values: R1(F)=0.041, wR(F2)=0.091 for observed reflec-
tions; residual electron density: À0.22 to 0.49 eꢆÀ3
;
1H NMR (600 MHz,
C6D6): d=0.98 (d, 3JPH =12 Hz, 9H; (CH3)3C), 1.10 (d, 3JPH =12 Hz, 9H;
(CH3)3C), 1.14 (d, 3JPH =12 Hz, 9H; (CH3)3C), 1.22 (d, 3JPH =12 Hz, 9H;
(CH3)3C), 1.33 (m, 4H; CH2), 2.27 (brm, 1H; CHH=CHCO2H), 2.76
(brm, 1H; CHH=CHCO2H), 3.36 (brm, 1H; CHH=CHCO2H),
13.56 ppm (brs, 1H; OH); 13C{1H} NMR (151 MHz, C6D6): d=23.6 (m;
CH2), 30.5 (m; (CH3)3C), 33.0 (d, 2JPC =23 Hz; CH2=CHCO2H), 34.6 (m;
(CH3)3C), 35.4 (m; (CH3)3C), 42.7 (d, 2JPC =14 Hz; CH2=CHCO2H),
182.7 ppm (s; CH2=CHCO2H); 31P{1H} NMR (243 MHz, C6D6): d=86.1
(d, 3JPP =53 Hz), 94.9 ppm (d, 3JPP =53 Hz); IR (KBr): v˜ =431, 454, 495,
529, 564, 578, 609, 664, 690, 792, 814, 838, 849, 899, 950, 989, 1022, 1055,
1095, 1140, 1180, 1279, 1367, 1392, 1452, 1479, 1561, 1637, 1659, 1685,
Ligand 1e (dtbpe): 31P NMR spectroscopic yield of 2e: 35%; 3e: 62%.
1H NMR (200 MHz, [D8]THF): d=1.21 (m, 2, 36H; 2 e, 3e CH2, CH3),
1.40 (m, 36H; 2e CH3), 1.77 (m, 6, 8H; 2e, 3d), 2.33 (s, 8H; CH2 COD),
5.36 (s, 4H; C2H4), 5.50 ppm (s, 4H; CH COD); 31P{1H} NMR (81 MHz,
[D8]THF): d=78.5 (d, J=8.9 Hz; 2e), 81.0 (d, J=8.9 Hz; 2e), 91.9 ppm
(s; 3e).
1908, 2718, 2867, 2900, 2948, 2979, 3041, 3085, 3407 cmÀ1
[Bis(di-tert-butylphosphino)ethane](sodium prop-2-enoate)nickel,
[Ni(h2-C2H3COONa)(dtbpe)] (5): [Ni(h2-C2H3COOH)
(dtbpe)] (6)
.
Ligand 1 f (dtbpp): 31P NMR spectroscopic yield of 3 f: 97%. Single crys-
tals suitable for X-ray diffraction were isolated from the HP NMR ex-
periment. Orange crystal (polyhedron); dimensions: 0.27ꢇ0.25ꢇ
0.21 mm3; crystal system: monoclinic; space group: C2/c; Z=4; a=
18.1611(14), b=13.1964(10), c=19.8885(15) ꢆ; a=90, b=109.6810(10),
g=908; V=4488.1(6) ꢆ3; a=1.308 gcmÀ3; T=200(2) K; qmax =28.328; ra-
diation: MoKa, l=0.71073 ꢆ; 0.38 w scans with a CCD area detector, cov-
ering a whole sphere in reciprocal space; reflections: 23309 measured,
AHCTUNGTRENNUNG
G
ACHTUNGTRENNUNG
(503 mg, 1.12 mmol) and sodium bis(trimethylsilyl)amide (209 mg,
1.12 mmol) were dissolved in THF (10 mL) and stirred at RT for 14 h. A
yellow precipitate formed. Filtration and washing with THF yielded com-
1
pound 5 (197 mg, 37%). H NMR (600 MHz, CD3OD): d=1.26 (m, 36H;
(CH3)3C), 1.76 (m, 4H; CH2), 1.89 (brm, 1H; CHH=CHCO2Na), 2.28
(brm, 1H; CHH=CHCO2Na), 2.86 ppm (brm, 1H; CH2=CHCO2Na);
13C{1H} NMR (151 MHz, CD3OD): d=24,6 (m; CH2), 31.2 (m; (CH3)3C),
5566 unique (RACHTUNGTRENNUNG ;
(int)=0.0241), 5129 observed (I>2s(I)); m=0.61 mmÀ1
2
2
35.0 (d, JPC =22 Hz; CH2=CHCO2Na), 35.5 (m; (CH3)3C), 47.9 (d, JPC
=
min/max transmission=0.85/0.88; 267 parameters refined; hydrogen
atoms were treated by using appropriate riding models; goodness of fit:
1.04 for observed reflections; final residual values: R1(F)=0.029,
wR(F2)=0.075 for observed reflections; residual electron density: 0.20 to
17 Hz; CH2=CHCO2Na), 187.3 ppm (s; CH2=CHCO2Na); 31P{1H} NMR
3
3
(243 MHz, CD3OD): d=87.2 (d, JPP =61 Hz), 93.5 ppm (d, JPP =61 Hz);
IR (KBr): v˜ =431, 454, 495, 529, 564, 578, 609, 664, 690, 792, 814, 838,
849, 899, 950, 989, 1022, 1055, 1095, 1140, 1180, 1279, 1367, 1392, 1452,
1479, 1561, 1637, 1659, 1685, 1908, 2718, 2867, 2900, 2948, 2979, 3041,
0.40 eꢆÀ3 1H NMR (200 MHz, [D8]THF): d=1.21 (m, 36H; 3 f CH3),
;
1.44 (m), 1.73 (s, 8H; 3 f CH2), 2.05 (m, 2H; 3 f CH2), 2.33 (s, 8H; CH2
COD), 5.36 (s, 4H; C2H4), 5.50 ppm (s, 4H; CH COD); 31P{1H} NMR
(81 MHz, [D8]THF): d=47.4 ppm (s; 3 f).
3085, 3407 cmÀ1
.
Ligand exchange of [bis(di-tert-butylphosphino)ethane](sodium prop-2-
enoate)nickel, [Ni(h2-C2H3COONa)(dtbpe)], with ethylene: [Ni(h2-
C2H3COOH)(dtbpe)] (6; 32.4 mg, 72.1 mmol) and sodium bis(trimethylsi-
AHCTUNGTRENNUNG
Formation of nickelalactone 2e at various temperatures: [NiACTHNUTRGNEUNG(cod)2]
AHCTUNGTRENNUNG
(138 mg, 500 mmol), dtbpe (159 mg, 500 mmol), and the internal standard
tetrabutylphosphonium tosylate (108 mg, 250 mmol) were dissolved in
THF (15 mL) and added to an autoclave (60 mL) by using a charger. The
autoclave was pressurized with ethylene at RT (5 bar, 15 min equilibra-
tion time), CO2 was added until a pressure of 40 bar was reached. After
15 min, the reaction was heated to the temperature given in the main
text and a sample was taken from the reaction by syringe and character-
ized by 31P NMR spectroscopy.
lyl)amide (69.7 mg, 369 mmol) were dissolved in [D8]THF (0.60 mL) and
stirred at RT for 6 h. The reaction mixture was transferred to a high-pres-
sure NMR tube and the tube was filled with ethylene (8 bar). The reac-
tion mixture was heated at 608C for 20 h. 31P{1H} NMR analysis revealed
the product to be mainly [NiACTHNUGRTENNUG AHCTUNGTRENN(UGN dtbpe)] (3e, 95.9%; d=91.9 ppm
(h2-C2H4)
(s)), along with minor amounts of dtbpe (4.1%; d=35.9 ppm (s)).
Ligand exchange of [bis(di-tert-butylphosphino)ethane](prop-2-enoic
ACTHNUTRGNEUNG
acid)nickel, [Ni(h2-C2H3COOH)(dtbpe)], with ethylene: [Ni(h2-
Kinetic experiments for formation of nickelalactone 2e in PhCl: [Ni-
C2H3COOH)ACTHNUGTRNENG(U dtbpe)] (6; 31.5 mg, 70.1 mmol) was dissolved in [D8]THF
ACHTUNGTRENNUNG(cod)2] (138 mg, 500 mmol), dtbpe (159 mg, 500 mmol) and the internal
(600 mL) and transferred to a high-pressure NMR tube. The tube was
filled with ethylene (8 bar) and heated at 608C for 18 h. 31P{1H} NMR
analysis revealed the product to be mainly the starting material (95.6%;
d=86.8 (d, 3JPP =55 Hz), 95.2 ppm (d, 3JPP =55 Hz)), along with minor
standard tetrabutylphosphonium tosylate (108 mg, 250 mmol) were dis-
solved in PhCl (15 mL) and added to an autoclave by using a charger.
The autoclave was pressurized with ethylene at RT (5 bar, 15 min equili-
bration time), CO2 was added until a pressure of 40 bar was reached.
After 15 min, the reaction was heated to 608C. Samples were taken from
the reaction by syringe and characterized by 31P NMR spectroscopy after
the indicated time periods (see the Supporting Information).
amounts of [NiACTHNUTRGENNGU ACHTUNGTERNN(UGN dtbpe)] (3e, 3.1%; d=91.9 ppm (s)) and free
(h2-C2H4)
dtbpe (1.3%; d=35.9 ppm (s)).
General procedure for cleavage of nickelalactone 2e to form [Ni(h2-
G
C2H3COONa)
ACHTUNGTREN(NUGN dtbpe)]: The corresponding base (100 mmol) and, if indi-
G
ACHTUNGTRENNUNG
cated, NaBArF (50.0 mmol) were added to a solution of 2e (11.2 mg,
Chem. Eur. J. 2012, 00, 0 – 0
ꢄ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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