J. Lach et al. / Polyhedron 117 (2016) 795–802
799
from moist ether and crystallization from methanol phosphanyl
glycine methanol solvates were obtained. As shown for 1dꢀMeOH,
the crystals may consist of only one enantiomer, while solution
NMR spectra detect equilibrium amounts of two diastereoisomers.
The kinetic lability of the phosphanyl glycines in solution pre-
vented separation of the diastereoisomers and limits applications
in transition metal complex chemistry and catalysis. The reaction
separated, washed with ether and dried in vacuum to give 0.90 g
(50%) of a white powder. Crystallization from methanol afforded
small colorless crystals of 1aꢀMeOH. Anal. Calc. for C19
PꢀCH OH (361.41): C, 66.46; H, 7.81; N, 3.88; found: C, 66.46; H,
7.91; N, 3.86%. The solution NMR spectra in [d ]THF displayed
two diastereoisomers (A, B) and minor amounts of Ph PH by partial
solvolysis (molar ratio after 4–6 h ca. 50:38:12, after 1 d ca.
3
H24NO -
3
8
2
1
3
1
with Ni(COD)
2
to nickel precatalysts, which by heating with ethy-
37:33:30 by integration of o-CH C NMR signals). H NMR ([d
8
]
3
3
lene under pressure lead to formation of efficient oligomerization
catalysts, shows however that the phosphanyl glycines may form
transition metal compounds that are sufficiently stable to act as
catalysts. The same high selectivity for oligomerization of ethylene
THF): d = 0.74 (d, J = 6.8 Hz, 3H, Me
B
), 0.78 (d, J = 7.0 Hz, 3H,
3
3
Me
Me
B
), 0.81 (d, J = 6.8 Hz, 6H, 2MeAB), 0.87 (d, J = 6.5 Hz, 3H,
), 0.90 (d, J = 6.4 Hz, 3H, Me ), 1.16–1.74 (m, 2H, 2CHAB),
A
3
A
2
2.43–2.55 (m, 2H, 2NCHAB), 4.14 (d, JPH = 2.5 or 4.5 Hz, 1H, PCH
B
),
), 5.70 (v br s, 3H, NH, OH),
7.21–7.34 (m, 6H, Ph), 7.40–7.67 (m, 4H, Ph); 3.26 (s, 3H, MeOH)
2
to linear
a
-olefins as observed for (organo)nickel phosphanyl acet-
4.15 (d, JPH = 3.2 or 5.4 Hz, 1H, PCH
A
ate catalysts, even in the presence of excess 1-hexene, suggest for-
ꢁ
13
1
mation of organonickel(II) P^COO -chelate complexes and that
ppm.
C{ H} NMR and DEPT-135 ([d
8
]THF): d = 15.46, 16.20,
), 34.27 (CH ),
), 59.36 (d, J = 8.4 Hz, NCH ), 60.53 (d,
B A
J = 15.1 Hz, PCH ), 62.09 (d, J = 14.1 Hz, PCH ), 128.49 (d,
ꢁ
other types of (organo)transition metal P^COO -chelate complexes
16.96, 17.93, 18.91, 19.49 (6 CH
3
), 32.03 (CH
B
A
3
3
might also be accessible from the new ligands by suitable methods
and perhaps be usable as catalysts.
58.01 (d, J = 7.9 Hz, NCH
B
A
1
1
3
3
3
J = 5.1 Hz, m-CH), 128.55 (d, J = 4.1 Hz, m-CH), 128.61 (d,
3
J = 4.3 Hz, m-CH), 128.70 (d, J = 5.4 Hz, m-CH), 128.96, 129.09,
29.68, 129.88 (4 p-CHAB), 133.86 (d, J = 17.5 Hz, o-CH
4
. Experimental
2
1
A
), 134.10
2
2
(
B
d, J = 18.6 Hz, o-CH ), 135.21 (d, J = 21.1 Hz, o-CH), 135.44 (d,
4.1. General remarks
2
1
1
J = 21.1 Hz, o-CH), 136.96 (br d, J = 14.6 Hz, i-C
q
), 137.85 (br d,
2
ꢁ
ꢁ
J = 18.2 Hz, i-C
9.77 (s, MeOH) ppm; P{ H} NMR ([d
integral ratio 45:55) ppm.
q
), 174.09 (d, J = 9.4 Hz, COO ), 174.84 (br, COO );
All manipulations were carried out under nitrogen atmosphere
3
1
1
4
8
]THF): d = 0.3, 0.7 (A, B)
using Schlenk techniques. The solvents were dried by standard
methods and freshly distilled before use. Diphenylphosphane
was synthesized from triphenylphosphane by cleavage of a phenyl
group with two equivalents of sodium in liquid ammonia and neu-
(
4.3. Diphenylphosphanyl-[(1R)-(1-phenyl-ethylamino)]-acetic acid
methanol solvate (1bꢀMeOH)
4
tralization with dry NH Cl [15]. Other chemicals were purchased
and used without further treatment. NMR spectra were recorded
on a multinuclear FT-NMR spectrometer ARX300 or Avance300
A freshly prepared solution of glyoxylic acid hydrate (534 mg,
1
13
31
(
Bruker) at 300.1 ( H), 75.5 ( C), and 121.5 ( P) MHz. For longer
5
.8 mmol) in diethyl ether (20 mL) was added at room temperature
NMR measurements, tubes should be sealed by melting or closed
by glass stoppers to prevent oxidation by air, which slowly diffuses
through commercial plastic caps. Chemical shifts d are given in
to solution of diphenylphosphane (1.08 g, 5.8 mmol) and
a
R(+)-methylbenzylamine (0.74 mL, 5.8 mmol) in diethyl ether
(10 mL). The solution was stirred overnight and separated from a
small amount of a sticky precipitate. The solvent was removed in
vacuum and methanol added (>20 mL). The solid residue dissolved
immediately, but shortly afterwards the methanol solvate of 1b
started to crystallize, forming a thick precipitate. It is much less
soluble in cold methanol than the primary product and insoluble
1
13
ppm and referred to tetramethylsilane for H and C and H
3
PO
4
3
1
(
85%) for P or to solvent signals calibrated with these references.
1
13
Coupling constants refer to JHH in H NMR and to JPC in C NMR
data unless stated otherwise. Assignments of the P-phenyl signals
(
two sets for each diastereoisomer) are indicated by i, o, m, p, by A
and B for different diastereoisomers (if distinguishable) and by an
additional apostrophe (’) for phenyl signals of the N-substituent.
The assignments are tentative and based on characteristic shift
ranges, coupling constants and intensity ratios, for 1dꢀMeOH addi-
tionally supported by HH- and CH-COSY experiments. 31P integrals,
referring to AQ 0.33 s and D1 2.0 s, are not quantitative but compa-
rable for closely related substances with similar relaxation times.
ESI-HRMS spectra of 1d were recorded with a high-resolution mass
spectrometer APEX IV (Bruker Daltonik). Because of the isomeriza-
in Et O. Crystallization from slightly warmed methanol (max.
2
3
0 °C), washing with diethyl ether and drying under vacuum pro-
vided 1.5 g (65%) of colorless needles, mp. (dec.) 104–105 °C. Anal.
Calc. for C22 OH (395.43): C, 69.86; H, 6.63; N, 3.54;
PꢀCH
found: C, 69.93; H, 6.71; N, 3.67%. The solution NMR spectra in
]THF revealed two diastereoisomers A and B, molar ratio
H22NO
2
3
[d
8
1
75:25% by integration of proton NMR signals. H NMR ([d ]THF):
d = 1.24 (d, J = 6.5 Hz, 3H, Me
3.71 (br q, J = 6.7 Hz, 2NCHAB), 3.77 (d, JPH = 3.2 Hz, 1H, PCHA),
8
3
3
A
), 1.25 (d, J = 6.6 Hz, 3H, Me
B
),
3
2
2
tion in solution the specific rotation ([a]) of polarized light was not
4
.20 (d,
7.43, 7.50–7.60 (m, 15H, 3 Ph); 3.26 (3H, MeOH) ppm. C{ H}
NMR and DEPT-135 ([d ]THF): d = 22.76 (Me ), 24.91 (Me ),
B
JPH = 1.2 Hz, 1H, PCH ), 4.5–6.0 (v br, 3H, NH, OH), 7.12–
13
1
given for the new asymmetric compounds. Melting points (uncor-
rected) were determined with a Sanyo Gallenkamp melting point
apparatus, elemental analysis with a CHNS-932 analyzer from
LECO using standard conditions.
8
B
A
3
3
57.80 (d, J = 9.1 Hz, NCH ), 58.63 (d, J = 9.6 Hz, NCH ), 60.71 (d,
B
A
1
), 60.93 (d, 1J = 19.7 Hz, PCH
0
J = 14.2 Hz, PCH
A
B
), 127.38 (p -CH
), 128.28 (2o -CH
A
),
0
0
0
1
27.53 (p -CH
B
), 127.68 (2o -CH
B
A
), 128.59 (d,
3
0
4.2. [(1S)-(1,2-Dimethyl-propylamino)]-diphenylphosphanyl-acetic
J = 6.7 Hz, 4 m-CH
2m-CH ), 128.82 (d, J = 7.7 Hz, 2m-CH
p-CH ), 129.69 (p-CH ), 129.78 (p-CH
), 134.08 (d, J = 18.7 Hz, 2o-CH
A
), 128.63, 128.77 (br, superimp. sh, 2m -CHAB,
3
acid methanol solvate (1aꢀMeOH)
B
B B
), 129.04 (p-CH ), 129.14
(
A
A
B
), 133.92 (d, 2J = 18.5 Hz,
2
2
A solution of Ph PH (1.01 g, 5.42 mmol) and (2S)(+)-2-amino-3-
2
2o-CH
2o-CH
B
A
), 135.17 (d, J = 21.2 Hz,
2
), 136.48 (d, 1J = 18 Hz,
methylbutane (0.47 g, 5.45 mmol) in diethyl ether (10 mL) was
added at room temperature (ca. 22 °C) to a solution of glyoxylic
acid hydrate (0.50 g, 5.43 mmol) in diethyl ether (20 mL), freshly
prepared in an ultrasound bath. After few minutes a precipitate
was observed. Stirring was continued overnight, the precipitate
A
), 135.38 (d, J = 20.9 Hz, 2o-CH
), 137.08 (d, J = 17.2 Hz, i-C ), ca. 137.7 (d, noise level, 2i-C
), 146.60 (i -C ), ca. 173.2 (d, noise level, COO
B
B
1
i-C
A
A
B
),
),
0
0
145.16 (i -C
173.84 (d, J = 12.0 Hz, COO
A
B
2
31
1
A
); 49.76 (MeOH) ppm. P{ H} NMR
([d ]THF): d = 1.0, 0.3 (A, B, integral ratio 73:27) ppm.
8