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lution was transferred to a homemade 75 mL stainless steel auto-
clave, which was purged with Ar. The autoclave was charged with
liquid NH3 (6 mL) at RT and then heated to 1708C. The reaction
was monitored by taking samples at intervals of 0.5, 1, 2, 3.75, 5.5,
7.5, 10, and 21 h. After 21 h, the reaction was allowed to cool
down. NH3 was released while the remaining mixture was kept
under an Ar atmosphere. To the mixture, a new batch of cyclohex-
anol (15 mmol, 1.59 mL) was added and fresh NH3 (6 mL) was
dosed at RT afterwards. The mixture was allowed to warm up
again to 1708C. This method was repeated in a total of six consec-
utive runs.
only a minor loss of activity even though the product was not
removed, which resulted in 600 catalyst turnovers.
Experimental Section
Chemicals and ligands L2, L6, L10–L12, L14–L15 were purchased
from Sigma–Aldrich and Acros; [Ru3(CO)12] was purchased from
Strem; and all chemicals were used as received. Ligands L1, L4,[7]
and L9[5] were synthesized according to a literature method report-
ed previously. Synthesis and catalysis reactions were performed
under an inert Ar atmosphere by using standard Schlenk tech-
niques. Product distribution and yield analyses were performed on
a Shimadzu GC17A instrument with an Ultra 2 column (25 m,
Synthesis of 1-phenyl-2-(dicyclopentylphosphino)-1H-pyrrole
(L3)
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0.2 mm i.d.). H NMR, 31P NMR, 13C NMR spectra were recorded on
200 and 400 MHz Varian Mercury spectrometers. The 1H and 13C
chemical shifts were reported in ppm downfield from TMS; 31P
chemical shifts were reported in ppm downfield from 85% H3PO4.
GC/MS analyses were conducted on a Shimadzu GCMS-QP2010 SE
with a DB-1ms column (10 m, 0.1 mm i.d.). Liquid NH3 was pur-
chased from LindeGas Benelux B.V. and used as received. NH3 was
dosed with a Bronkhorst Liqui-Flow mass flow meter/controller.
Direct aminations of alcohols were performed in a homemade
75 mL stainless steel autoclave equipped with a manometer and
a sampling unit for samples (50 mL). Samples were subjected di-
rectly to GC without further workup.
This compound was prepared following a modified literature
method.[16] In a three-neck round-bottom Schlenk flask, 1-phenyl-
pyrrole (1.432 g, 10 mmol) was dissolved in dry degassed hexane
(30 mL). To this, N,N,N’,N’-tetramethyl-1,2-ethane (TMEDA; 2.25 mL,
15 mmol, 1.5 equiv.) was added followed by a solution of nBuLi
(2.5m) in hexane (4 mL, 10 mmol). The mixture was heated to
reflux until a clear bright red solution was obtained. Chlorodicyclo-
pentylphosphine (2.047 g, 10 mmol) was then added dropwise at
reflux temperature. After the addition, the mixture was heated to
reflux for an additional hour and then cooled to RT. Degassed
water was added to quench the reaction. The layers were separat-
ed, and the aqueous layer was extracted twice with hexane (2ꢁ
15 mL). All hexane fractions were combined, dried over Na2SO4,
and filtered. The solvents were evaporated, and the pure ligand
was obtained as an off-white solid (99%, 3310 mg). 1H NMR
(200 MHz, C6D6): d=1.4 (m, 16H cyclopentyl), 2.0 (m, 3J=4.2 Hz,
2H cyclopentyl), 6.3 (q, 3J=3.2 Hz, 1H pyrrole), 6.5 (dd, 3J=1.6,
General method for the direct amination of secondary
alcohols with [Ru3(CO)12] and phosphine ligands
[Ru3(CO)12] (0.066 mol%) was weighed into a Schlenk tube and was
purged with Ar. To this, dry degassed tert-amyl alcohol (13.3 mL)
was added. Subsequently, the ligand (1 mol%, Ru/P=1:1) and the
alcohol (10 mmol) were added and the whole mixture was heated
gently to dissolve the components. The bright red solution was
transferred to a homemade 75 mL stainless steel autoclave, which
was previously purged with Ar. The autoclave was charged with
liquid NH3 (6 mL) at RT and then heated to 150 or 1708C for the
appropriate time.
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3.2 Hz, 1H pyrrole), 6.8 (q, J=2.8 Hz, 1H pyrrole), 7.1 (m, J=1.6,
7.0, 4H phenyl), 7.3 ppm (dt, 3J=1.2, 8.2 Hz, 1H phenyl); 13C{1H}
NMR (50 MHz, C6D6): d=25.6 (CH2), 25.7 (CH2), 26.5 (CH2) 26.6
(CH2), 30.78 (CH2), 30.92 (CH2), 31.17 (CH2), 31.21 (CH2), 38.6 (CP cy-
clopentyl), 38.8 (CP cyclopentyl), 109.6 (CH pyrrole), 116.6 (CP pyr-
role), 125.3 (CH pyrrole), 126.6 (CH phenyl), 127.3 (CH phenyl),
128.1 (CH pyrrole), 128.5 (CH phenyl), 130.8 (CH phenyl), 131.0 (CH
phenyl), 141.1 ppm (CN phenyl); 31P{1H} NMR (162 MHz, C6D6): d=
À28.4 ppm (s).
Method for the preformation reactions
[Ru3(CO)12] (0.066 mmol, 42.5 mg) was weighed into a Schlenk tube
and was evacuated and purged with Ar. To this, L9 (0.1 mmol,
44.0 mg Ru/P=1:1) was added and the compounds were dissolved
in tert-amyl alcohol (13.3 mL). The mixture was transferred to
a homemade 75 mL stainless steel autoclave, which was previously
purged with Ar. In the case of the preformation with NH3, NH3
(6 mL) was added and the mixture was heated to 1708C for 18 h.
After this, the mixture was cooled down slowly and cyclohexanol
(10 mmol) was added and fresh NH3 (6 mL) was dosed at RT. The
mixture was heated to 808C and allowed to stand at this tempera-
ture for 2 h. A sample was taken at 0.5 h intervals. After no conver-
sion was detected, the temperature was increased to 1008C and
the same method was followed.
Synthesis of 1-phenyl-2-(diethylphosphino)-1H-pyrrole (L5)
This compound was prepared following a modified literature
method.[16] In a three-neck round-bottom Schlenk flask, 1-phenyl-
pyrrole (1.432 g, 10 mmol) was dissolved in dry degassed hexane
(30 mL). To this, TMEDA (2.25 mL, 15 mmol, 1.5 equiv.) was added
followed by a solution of nBuLi (2.5m) in hexane (4 mL, 10 mmol).
The mixture was heated to reflux until a clear bright red solution
was obtained. Chlorodiethylphosphine (1.245 g, 10 mmol) was
then added dropwise at reflux temperature. After the addition, the
mixture was heated to reflux for an additional hour and then
cooled to RT. Degassed water was added to quench the reaction.
The layers were separated, and the aqueous layer was extracted
twice with hexane (2ꢁ15 mL). All hexane fractions were combined,
dried over Na2SO4, and filtered. The solvents were evaporated, and
the pure ligand was obtained as a yellow oil. 1H NMR (400 MHz,
C6D6): d=0.85 (t, 3J=7.6 Hz, 3H ethyl), 0.89 (t, 3J=7.6 Hz, 3H
Method for the repetitive batch reaction
[Ru3(CO)12] (1 mol%, 32 mg, 0.05 mmol) was weighed into a Schlenk
tube and was purged with Ar. To this, dry degassed tert-amyl alco-
hol (20 mL) was added. Subsequently, L9 (1 mol%, 65.9 mg) and
the alcohol (15 mmol, 1.59 mL) were added and the whole mixture
was heated gently to dissolve the components. The bright red so-
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ethyl), 1.4 (q, J=7.6 Hz, 2H ethyl), 1.5 (q, J=7.6 Hz, 2H ethyl), 6.4
(d, 3J=2.4 Hz, 1H pyrrole), 6.5 (s, 1H pyrrole) 6.9 (s, 1H pyrrole),
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7.00 (m J=7.2 Hz, 4H phenyl), 7.2 ppm (d, J=7.2 Hz, 1H phenyl);
13C{1H} NMR (100 MHz, C6D6): d=9.7 (CH3), 9.8 (CH3), 20.3 (CH2),
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