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W.S. Seo et al. / Journal of Organometallic Chemistry 640 (2001) 79–84
asymmetric unit contains five equivalent molecules (5-
A, 5-B, 5-C, 5-D and 5-E), which slightly differ from
one another in bond lengths and angles. The average
bond lengths of TiꢀN(pyrrolyl), TiꢀN(3) and
mmol) was added to a THF solution (200 ml) of 1 (5.80
g, 40.5 mmol) at 0 °C. The reaction mixture was heated
at 40 °C for 10 h and quenched with water. The
aqueous layer was extracted with Et2O (4×50 ml). The
combined organic layer was washed with water and
brine, dried over anhydrous MgSO4, filtered, and evap-
orated under vacuum. After purification by column
chromatography (EtOAc–hexane=1/8), a colorless oil
of 2 (5.59 g, 38.5 mmol, 95%) was obtained as a ca. 2:1
,
TiꢀCp(centroid) are 2.02(2), 1.86(2) and 1.99 A, respec-
tively, and the average bond angle of Cp(cen-
troid)ꢀTiꢀN(pyrrolyl) is 105°. All other bond lengths
and angles are within the expected ranges.
1
mixture of 1,3- and 1,2-isomers. H-NMR (CDCl3, 25
3. Experimental
°C): C5H5-olefinic, C4H3NH, and NH protons could
not be exactly assigned to each isomer: l 7.88 (br s,
NH), 6.67–5.96 (m, C4H3NH and C5H5-olefinic). 1,2-
isomer: l 3.71 (s, 2H, ꢀCH2ꢀ), 3.00 (m, 2H, C5H5-
aliphatic). 1,3-isomer: l 3.75 (s, 2H, ꢀCH2ꢀ), 2.89 (m,
2H, C5H5-aliphatic).
3.1. General comments
All reactions were carried out under an inert atmo-
sphere of Ar by using either standard Schlenk or dry-
box techniques. Tetrahydrofuran (THF) and toluene
were distilled from Na/K alloy under N2 atmosphere.
CH2Cl2 was refluxed over CaH2 and then distilled
under N2 atmosphere.
3.4. Preparation of
[(p5-C5H4)CH2(2-C4H3N)]Ti(NMe2)2 (3)
Ti(NMe2)4 purchased from Strem was used without
further purification. Pyrrolidine (Aldrich) was freshly
distilled under nitrogen before use. Silica gel (Merck,
230–400 mesh) was used for column chromatography.
1H- (400 MHz) and 13C- (100 MHz) NMR spectra were
recorded on a Bruker AVANCE-400 spectrometer.
Mass spectra (EI) were obtained by the staff of the
Korea Basic Science Center using a JEOL JMS-SX-
102A mass spectrometer, and all m/z values are refer-
enced to 48Ti. Elemental analyses were provided by the
staff of the Energy and Environment Research Center
at KAIST.
A toluene solution (10 ml) of 2 (0.36 g, 2.49 mmol)
was added to a toluene solution (10 ml) of Ti(NMe2)4
(0.56 g, 2.49 mmol) at 0 °C. The reaction mixture was
warmed to r.t. and stirred for 3 h. Evaporation of the
solvent and recrystallization in CH2Cl2 at −20 °C gave
3 (0.60 g, 2.14 mmol, 86%) as orange crystals. 1H-NMR
(CDCl3, 25 °C): l 6.90 (m, 1H, C4H3N), 6.05 (m, 1H,
C4H3N), 5.85 (m, 1H, C4H3N), 6.19 (m, 2H, C5H4),
6.12 (m, 2H, C5H4), 3.86 (s, 2H, ꢀCH2ꢀ), 3.21 (s, 12H,
(NMe2)2). MS (70 eV): m/z 279 [M+]. Anal. Found: C,
60.08; H, 7.63; N, 15.28. Calc. for C14H21N3Ti: C,
60.22; H, 7.58; N, 15.05%.
3.2. Preparation of (C5H4)CH(2-C4H3NH) (1)
3.5. Preparation of 1,3- and
1,4-{CH2(2-C4H3NH)}2C5H4 (4)
To a methanol solution (40 ml) of pyrrole-2-carbox-
aldehyde (3.97 g, 41.8 mmol) and cyclopentadiene (6.90
g, 104.4 mmol) was added pyrrolidine (5.94 g, 83.5
mmol) at 0 °C. The reaction mixture was stirred for 90
min at room temperature (r.t.). Glacial AcOH (5.02 g,
83.5 mmol) was added to the red solution at 0 °C to
quench the reaction. The reaction mixture was diluted
with ether (50 ml) and water (50 ml). The aqueous
portion was extracted with ether (4×50 ml). The com-
bined organic portion was washed with water and
brine, then dried over anhydrous MgSO4, filtered, and
evaporated under reduced pressure. Purification by
column chromatography (EtOAc–hexane=1/8) af-
forded 1 (5.80 g, 40.5 mmol, 97%) as a red solid.
1H-NMR (CDCl3, 25 °C): l 8.62 (br s, 1H, NH), 6.67
(s, 1H, ꢀCHꢀ), 7.02–6.60 (m, 3H, C4H3NH), 6.62–6.28
(m, 4H, C5H4).
To a MeOH solution (15 ml) of pyrrole-2-carbox-
aldehyde (1.02 g, 10.7 mmol) and 2 (3.10 g, 21.4 mmol)
was added pyrrolidine (1.52 g, 21.4 mmol) at r.t. The
reaction mixture was stirred for 3 h. Glacial AcOH
(1.28 g, 21.4 mmol) was added to the red solution at 0
°C. The reaction mixture was diluted with ether (30 ml)
and water (30 ml). The aqueous portion was extracted
with Et2O (4×30 ml) and the combined organic por-
tion was washed with water and brine, dried over
anhydrous MgSO4, filtered and evaporated under re-
duced pressure. Purification by column chromatogra-
phy (EtOAc–hexane=1/5) afforded a ca. 1:4 mixture
of 1,2- (minor) and 1,3-disubstituted (major) fulvene-
type cyclopentadiene compounds (1.17 g, 5.26 mmol,
49%) with respective cis and trans isomers. To a THF
solution (40 ml) of this mixture of fulvene compounds
(1.17 g, 5.26 mmol) was added a THF solution of
LiAlH4 (1.0 M, 5.26 ml, 5.26 mmol) at 0 °C. The
reaction mixture was heated at 40 °C for 10 h and
quenched with water. The aqueous layer was extracted
3.3. Preparation of (C5H5)CH2(2-C4H3NH) (2)
A THF solution of LiAlH4 (1.0 M, 40.5 ml, 40.5
Seo, Won Seok
