Synthesis of diterpenoid indole derivatives via tethered chromium alkynylaminocarbenes

Article abstract of DOI:10.1016/S0022-328X(01)00844-0

Thermolysis of podocarpane-tethered chromiumalkynylaminocarbenes gives indole derivatives in moderate yields. (Arylalkynyl)aminocarbenes could not be isolated. Ester derivatives were formed due to trapping of the intermediate ketene in situ with butan-1-o

Full text of DOI:10.1016/S0022-328X(01)00844-0

Journal of Organometallic Chemistry 629 (2001) 131–144
www.elsevier.com/locate/jorganchem
Synthesis of diterpenoid indole derivatives via tethered chromium
alkynylaminocarbenes
Paul D. Woodgate *, Hamish S. Sutherland
Department of Chemistry, The Uni6ersity of Auckland, Pri6ate Bag 92019, Auckland, New Zealand
Received 9 March 2001; accepted 31 March 2001
Abstract
Thermolysis of podocarpane-tethered chromiumalkynylaminocarbenes gives indole derivatives in moderate yields. (Ary-
lalkynyl)aminocarbenes could not be isolated. Ester derivatives were formed due to trapping of the intermediate ketene in situ
with butan-1-ol. © 2001 Elsevier Science B.V. All rights reserved.
Keywords: Chromium; Alkynylaminocarbenes; Diterpenoid; Indole
1. Introduction
of functionalised 2-alkynylaniline derivatives, them-
selves prepared by the palladium-catalysed coupling of
a terminal alkyne (RCꢀCH; R=H, SiMe3, phenyl,
t-butyl, pentyl, pyridinyl, ferrocenyl) with 2-iodoani-
line. Although most Sonogashira reactions [10–12] in-
volving aryl iodides can be carried out at room
temperature, substrates possessing an electron donating
group ortho to the halide undergo oxidative addition
more slowly and consequently benefit from a slightly
elevated reaction temperature [13]. The coupling reac-
tions were therefore performed by reacting 2-iodoani-
line with the alkyne in the presence of Pd(PPh3)2Cl2 and
CuI, in either diethylamine or triethylamine at ca. 40°C.
2-Ethynylaniline (3) was synthesised by desilylation
(KOH–MeOH/H2O, 72%) [14] of 2-(trimethylsi-
lylethynyl)aniline (4) (from 2-iodoaniline and trimethyl-
silylethyne, diethylamine, 30°C, 76%) [15]). Reaction of
2-iodoaniline with phenylethyne in triethylamine at
40°C gave 2-(phenylethynyl)aniline (5) (94%) [16]. The
coupling of 3,3-dimethylbutyne with 2-iodoaniline us-
ing CuI (1 mol%) and Pd(PPh3)2Cl2 (2 mol%) was
performed at room temperature due to the low
A variety of fused nitrogen heterocycles have been
synthesised from tethered alkynyl aminocarbenes by
insertion of an alkyne intramolecularly [1–9]. For ex-
ample, thermolysis of a wide range of vinyl and aryl
2-alkynylanilinocarbene chromium complexes gives
9H-carbazoles and 11H-benzo[a]carbazoles [3–5]. The
presence of the indole ring system in a wide variety of
biologically active molecules led us to investigate the
synthesis and reactions of some diterpenoid alkyny-
lanilinocarbene chromium complexes, as a potential
route to indenoindole 1 and naphthoindole 2 deriva-
tives containing six fused rings.
2. Results and discussion
The aminocarbene complexes were synthesised by
reaction of a podocarpane acyloxycarbene with a range
* Corresponding author. Tel.: +64-9-3737599, ext. 8262; fax: +
64-9-3737422.
E-mail address: p.woodgate@auckland.ac.nz (P.D. Woodgate).
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)00844-0

132
P.D. Woodgate, H.S. Sutherland / Journal of Organometallic Chemistry 629 (2001) 131–144
synthesised by adding a solution of a 2-(alkynyl)aniline
and triethylamine directly to a solution of the acetyl-
oxycarbene at −78°C. Thus, addition of 2-(trimethyl-
silylethynyl)aniline (4) (1.07 molar equivalents) and
Et3N (1.14 molar equivalents) to a solution of the
acetyloxycarbene 12 followed by chromatography on
silica gel gave pentacarbonyl[(2-(trimethylsilyl)ethynyl)-
(13 - (12,19 - dimethoxypodocarpa - 8,11,13 - triene))-
carbene]chromium (13) (84%) as a stable yellow–or-
boiling point (37–38°C) of this alkyne. Although this
reaction required 48 h, as well as the addition of further
CuI (11 mol%) after 24 h, it afforded 2-(3%,3%-dimethyl-
butynyl)aniline (6) in high yield (95%). 2-(Hept-1-
yl)aniline (7) was synthesised (98%) by the PdꢁCu(I)
mediated coupling of 2-iodoaniline with hept-1-yne in
diethylamine at 30°C. Treatment of ethynylferrocene
[17] with 2-iodoaniline using standard Sonogashira con-
ditions in diethylamine at 30°C for 18.5 h afforded only
starting material. However, the use of a higher molar
ratio of CuI (23 mol%) and increasing the reaction
temperature to 60°C gave 2-(ferrocenyl)ethynylaniline
(8) (99%) after 24 h. In contrast, coupling of 2-
ethynylpyridine (from 2-bromopyridine and trimethylsi-
lylethyne, 91% [18]) with 2-iodoaniline using
Sonogashira conditions to give 2-(2%-pyridyl)-
ethynylaniline (9) was more efficient at room tempera-
ture (45 h; 65%) than at 40°C (34%).
1
ange foam. H-NMR analysis indicated that 13 was a
mixture (1.75:1) of E and Z isomers (NHE, 10.89 ppm;
NHZ, 10.06 ppm) [4]. In the 13C-NMR spectrum, sig-
nals due to alkynyl carbons were observed at 98.8
(CꢀCSiMe3) and 103.8 ppm (CꢀCSiMe3), and those
due to the carbene carbon at 289.0 and 289.1 ppm.
Similarly, pentacarbonyl[(2-(ethynyl)aniline)(13-(12,19-
dimethoxypodocarpa-8,11,13-triene))carbene]chromium
(14) was synthesised (67%) by aminolysis of 12 with
2-ethynylaniline (3) (1.03 molar equivalents). Anili-
nocarbene 14 existed as a mixture (1.9:1) of E and Z
isomers (NHE, 10.89 ppm; NHZ, 10.06 ppm).
The 2-alkynylaniline derivatives were then reacted
with a podocarpane chromium acetyloxycarbene to give
the anilinocarbene complexes. The diterpenoid acety-
loxycarbenes were synthesised by in situ acetylation of
the corresponding tetraalkylammonium complex. The
procedure used for synthesis of the acylate complex was
based on literature methods [19,20], although some
modifications were introduced. Thus, addition of
13-lithio-12,19-dimethoxypodocarpa-8,11,13-triene to
Cr(CO)6 gave the lithium acylate 10. An aqueous solu-
tion of benzyltriethylammonium chloride was added to
an aqueous solution of 10 to give water-insoluble ben-
Addition of 2-(1,1-dimethylbutynyl)aniline (6) (1.02
molar equivalents) to 12 in the presence of Et3N (1.11
molar equivalents) gave pentacarbonyl[(2-(1,1-di-
methylbutynyl)aniline))(13 - (12,19 - dimethoxypodo-
carpa-8,11,13-triene))carbene]chromium (15) (77%) as a
mixture (5:1) of E and Z isomers (NHE, 10.81 ppm;
NHZ, 10.01 ppm). In the 13C-NMR spectrum signals
due to alkynyl carbons were observed at 73.8 (CꢀCt-
Bu), and 93.9 ppm (CꢀCt-Bu) while a signal at 287.4
ppm was characteristic of a carbene carbon.
zyltriethylammonium
pentacarbonyl[(oxo)(13-(12,19-
dimethoxypodocarpa-8,11,13-triene))carbene]chromium
(11) (78%). Tetraalkylammonium salts exhibit a strong
b-shielding effect [21]; the 13C-NMR spectrum of 11
showed the signal due to the triethylammonium methyl
group (b to nitrogen) at 8.1 ppm, and the benzyl
methylene signal was broad due to coupling with the
14N nucleus.
Addition of a solution of acetyl bromide (1.05 molar
equivalents) to a solution of the salt 11 gave the red–
purple acetyloxycarbene complex 12. Since acyloxycar-
benes are sensitive to heat, moisture, air, and light, the
acetylation was performed at −20°C in flame-dried,
foil-covered flasks. The anilinocarbenes were then
Reaction of 2-(heptyn-1-yl)aniline (7) (1.00 molar
equivalent) with 12 in the presence of Et3N (1.13 molar
equivalents) gave pentacarbonyl[(2-(heptyn-1-yl)ani-
line)(13 - (12,19 - dimethoxypodocarpa - 8,11,13 - triene))-
carbene]chromium (16) (64%) as a relatively unstable
orange oil. The infrared spectrum showed absorptions
characteristic of carbonyl ligands at 2054, 1977 and
1931 cm−1, but attempts to obtain NMR spectra in
either CDCl3 or C6D6 led to rapid decomposition of
this (2-alkylethynyl)anilinocarbene complex. Further-
more, all attempts to isolate the analogous (2-
arylethynyl)aminocarbenes 17–19 were unsuccessful,
and decomposition of these anilinocarbenes either in

P.D. Woodgate, H.S. Sutherland / Journal of Organometallic Chemistry 629 (2001) 131–144
133
Table 1
followed by aerial oxidation of the chromium-contain-
ing products gave butyl 2-[13%-(12%,19%-dimethoxypodo-
carpa-8%,11%,13%-triene]-a-(trimethylsilyl)-1H-indole-3-
acetate (20) (14%). Accurate measurement of the molec-
Indole 1H-NMR signals for the silyl derivative 20
Hydrogen
Signal (l ppm; coupling constant Hz)
ular ion (M+ 589.3580) in the mass spectrum sup-
’
H(4)
H(5)
H(6)
H(7)
7.66 (bd, J=7.7 Hz); 7.80 (bd, J=8.0 Hz)
7.06 (td, J=8.1, 1.1 Hz); 7.11 (td, J=8.1 Hz)
7.13 (td, J=8.2, 1.2 Hz); 7.18 (td, J=8.1, 1.2 Hz)
7.29 (bd, J=8.0 Hz); 7.35 (bd, J=7.7 Hz)
ported the molecular formula C36H51NO4Si. A broad
absorption centred at 3369 cm−1 corresponding to the
indole NꢁH stretching vibration, and an intense peak at
1730 cm−1 indicative of an ester carbonyl group, were
observed in the infrared spectrum. The ester was a
mixture (1:1) of epimers; atoms which are close to the
new stereogenic centre showed different NMR chemical
shifts for each epimer (lCꢂO 172.4, 173.9 ppm; lCH
36.5(8), 36.6(4); lCH 3.79(6), 3.80(4) ppm). Each of the
indolyl aromatic protons also showed a different chem-
ical shift for each epimer in the 1H-NMR spectrum
(Table 1).
solution or during chromatography meant that they
had to be thermolysed (see below) without prior isola-
tion. There are reported examples of stable tethered
(arylalkynyl)aminocarbenes [4,5,8,9].
A
(phenyl-
alkynyl)aminocarbene having a propyl spacer between
the aminocarbene nitrogen and the alkyne is stable
while the corresponding compound with an ethyl spacer
is not; interestingly, both of the related (trimethylsilyl)-
alkynyl derivatives are stable [6]. Phenylethyne poly-
merises more readily than trimethylsilylethyne, and so
polymerisation of the phenylethynyl group in the anili-
nocarbene may cause gross decomposition of the car-
bene. However, this does not explain why one of the
phenylalkynyl aminocarbenes synthesised by Wulff [6]
is unstable while the other one is stable. The reason for
the instability of the (arylalkynyl)aminocarbenes in the
present work remains unknown.
Although tetrahydrofuran, acetonitrile, t-butyl
methyl ether or hexane have been used as the solvent in
thermolysis studies of aminocarbenes [3], dibutyl ether
or toluene are most commonly employed. However, the
yields of indole derivatives are generally higher when
dibutyl ether is used instead of toluene as the solvent
for thermolysis of (alkynyl)aminocarbenes, the superi-
ority of dibutyl ether being significant when the prod-
ucts are indolylketenes [4]. Heating the diterpenoid
trimethylsilyl anilinocarbene derivative 13 in dibutyl
ether at 85°C for 1.5 h under a stream of nitrogen
Formation of the butyl ester 20 instead of its parent
carboxylic acid was unexpected. Although the dibutyl
ether had been distilled from calcium hydride under
nitrogen immediately before use, GLC analysis of the
distillate indicated that some butan-1-ol was present;
although only in trace amount, it corresponded to 10
molar equivalents relative to the diterpenoid anilinocar-
bene. A route to the ester is included in Scheme 1.
Insertion of the alkyne into the carbene gives the
indenoyl carbene 21, which undergoes insertion of car-
Scheme 1.

134
P.D. Woodgate, H.S. Sutherland / Journal of Organometallic Chemistry 629 (2001) 131–144
bon monoxide to afford ketene 22; nucleophilic attack
by butan-1-ol then gives 20. Interestingly, this reaction
showed no stereofacial selectivity, both epimers of the
product being isolated in equal amounts.
signals due to the indolyl group was made using the
13C–1H correlation spectrum. A plausible mechanism
for the formation of the pentyl ketone 25 is included in
Scheme 1. Insertion of the alkyne into the chromium–
carbene bond gives the indolyl carbene 26, oxidation of
which gives 25.
Heating a solution of the t-butylethynyl anilinocar-
bene 15 in dibutyl ether at 85°C gave a low yield of a
product assigned as butyl 2-[13%-(12%,19%-dimethoxy-
podocarpa-8%,11%,13%-triene)]-a-(1,1-dimethylethyl]-1H-
indole-3-acetate (23) by high resolution mass spec-
Thermolysis of the (ethynyl)anilinocarbene 14 gave
2-(13%-(12%,19%-dimethoxypodocarpa-8%,11%,13%-triene))-3-
(pentan-2-one)-1H-indole (27) (7%). The structure of
27 was indicated in the mass spectrum by the molecu-
troscopy (M+ 573.3813, C37H51NO4), the base peak at
’
lar ion (M+ 487.3083, C32H41NO3) and by the base
’
’
m/z 516 being consistent with loss of C4H9 from the
peak at m/z 416, which arose from loss of
CH3CH2CH2CO . Although an indolylcarbonyl struc-
molecular ion. Repeated attempts to purify this com-
pound, either by PLC (silica gel; hexanes–ether, 1:1) or
by using analytical TLC plates (hexanes–ether, 2:1)
failed to give material which was sufficiently pure for
NMR analysis. It is suspected that hydrolysis of the
butyl ester 23 led to the carboxylic acid and then to
other decarboxylation-derived products. Thermolysis
of 15 in toluene at 85°C for 2 h was a cleaner but still
low yielding reaction, affording 2-[13%-(12%,19%-
dimethoxypodocarpa-8%,11%,13%-triene)]-a-(1,1-dimethyl-
ethyl)-1H-indole-3-acetic acid (24) (17%), also as a
mixture (1:1) of epimers. The elemental composition
(C33H43NO4) of the molecular ion was confirmed by
’
ture was considered, the spectral data were significantly
different from that of the 3-(hexan-1-one)-1H-indole
derivative 25. For example, while H(4) was deshielded
significantly in 25 (8.35 ppm), the signal at 7.50 ppm
1
due to H(4) in the H-NMR spectrum of the 3-(pen-
tan-2-one) derivative indicated that the carbonyl group
in 27 was not close spatially to H(4). The singlet at
3.83 ppm was assigned to the methylene group bonded
to the carbonyl group and the C(3) indolyl carbon.
13C-NMR spectral data (lCO=210 ppm) also indicated
that 27 was a dialkyl ketone rather than an alkylaryl
ketone (l:199 ppm).
mass spectroscopy (M+ 517.3191), the base peak at
’
m/z 460 resulting from the loss of a t-butyl radical
from the molecular ion. Signals at 175.0 and 175.2
ppm in the 13C-NMR spectrum confirmed the presence
of a carboxylic acid.
Thermolysis of the (pentylethynyl)anilinocarbene 16
in dibutyl ether gave 2-[13%-(12%,19%-dimethoxypodo-
carpa-8%,11%,13%-triene)]-3-(hexan-1-one)-1H-indole (25)
(44%); products derived from addition of either butan-
1-ol (to give an ester) or water (to give an acid) to an
intermediate ketene were not detected. High resolution
mass spectroscopy gave the molecular ion at m/z
501.3256 (C33H43NO3), loss of a pentyl radical from
the molecular ion yielding a resonance-stabilised in-
doloyl cation (m/z 430, 62%). A signal at 210.3 ppm in
the 13C-NMR spectrum and an intense absorption at
1667 cm−1 in the infrared spectrum confirmed the
presence of an arylalkyl ketone. The signal due to the
indolyl proton H(4) was shifted downfield (8.35 ppm)
in the 1H-NMR spectrum due to deshielding by the
proximal carbonyl group. Assignment of the carbon
The intermediate in the formation of 27 is presumed
to be a 3-indolyl chromium hydridocarbene. Analo-
gous tungsten hydridocarbenes are known to react with
either tetrahydrofuran or diethyl ether to give products
corresponding to the insertion of the arylidene ligand
into the a-CH bond of these ethereal solvents [22]. By
analogy, a feasible pathway (Scheme 2) for formation
of the 3-(pentan-2-one)-1H-indole 27 involves insertion
of the alkyne into the chromium–carbene bond to give
an indolyl chromium hydridocarbene 28 which inserts
into the a-CH bond of butan-1-ol to give the
secondary alcohol 29, oxidation of which affords ke-
tone 27.
As mentioned above, the anilinocarbenes 17, 18, and
19 having, respectively, a phenyl, ferrocenyl, or pyridyl

P.D. Woodgate, H.S. Sutherland / Journal of Organometallic Chemistry 629 (2001) 131–144
135
indole (32) (8%) and butyl 2-[13%-(12%,19%-dimethoxy-
podocarpa - 8%,11%,13% - triene)] - a - (ferrocenyl) - 1H-
indole-3-acetate (33) (16%), whose structures followed
from their spectroscopic data.
The pyridinylalkynyl anilinocarbene 19 was synthe-
sised by aminolysis of 12 with 2-(2%-pyridyl)ethynyl-
aniline (9). TLC analysis indicated that 19 was highly
unstable, some decomposition being detected in situ.
Not unexpectedly, therefore, low yields resulted from
thermolysis of this anilinocarbene in dibutyl ether at
85°C;
triene)]-a-(2-pyridylmethyl)-1H-indole (34) (3%) and
butyl 2-[13%-(12%,19%-dimethoxypodocarpa-8%,11%,13%-
triene)]-a-(2-pyridyl)-1H-indole-3-acetate (35) (3%)
were recovered as an inseparable mixture.
2-[13%-(12%,19%-dimethoxypodocarpa-8%,11%,13%-
Scheme 2.
substituent on the alkyne terminus had to be synthe-
sised and thermolysed without isolation. Reaction of
the acetyloxycarbene 12 with the appropriate 2-alkyny-
laniline and triethylamine gave the corresponding anili-
nocarbene. The solvent was removed in vacuo and
replaced with dibutyl ether; heating at 85°C then gave
the indole derivatives. Thus, thermolysis of the phenyl
anilinocarbene 17 gave 2-[13%-(12%,19%-dimethoxypodo-
carpa-8%,11%,13%-triene)]-3-benzyl-1H-indole (30) (7%)
and butyl 2-[13%-(12%,19%-dimethoxypodocarpa-8%,11%,13%-
triene)]-a-phenyl-1H-indole-3-acetate (31) (7.5%). The
1H-NMR spectrum of the benzyl derivative 30 included
an AB coupled system, doublets at 4.20 and 4.25 ppm
(J=16.7 Hz) being consistent with the presence of the
diastereotopic benzylic methylene hydrogens. The two
outer wings of this pair of doublets had almost zero
intensity, reflecting the low ratio for the difference in
chemical shifts to the coupling constant (Dw/J=1.20).
These doublets correlated with the signal due to a CH2
group at 31.0 ppm in the 13C-NMR spectrum. Full
structural assignment was made using COSY, 13C–1H
and long-range 13C–1H spectra. Loss of a phenyl radi-
Indenoindole 1 and carbazole 2 products were not
isolated from the present reactions. The electrocyclic
ring closure leading to these hexacyclic compounds
requires a transition state in which the ketene and
indole groups are essentially coplanar [4,5], a conforma-
tion which is apparently unable to be attained in the
podocarpane derivatives due to steric encumbrance.
Thermolysis of the isolated diterpenoid-tethered
alkynylaminocarbenes gave indole derivatives in low
yields, while direct thermolysis of the (ary-
lalkynyl)aminocarbenes without isolation was charac-
terised by the formation of more than one heterocyclic
product. The low yield of indoles is attributed to the
steric bulk around the carbene moiety, precluding effi-
cient insertion of an alkyne [5]. Nevertheless, the large
number of carbon–carbon bonds formed combined
with the increase in synthetic complexity offsets the low
yields of the indole products obtained.
cal from the molecular ion (M+ 493.2987) gave a weak
’
3. Experimental
fragment peak at m/z 416 in the mass spectrum. The
butyl ester 31 was isolated as a mixture (4:5) of epimers,
the methine a hydrogens giving rise to singlets at
5.33(0) and 5.33(5) ppm in the 1H-NMR spectrum.
Separate signals (8.52, 8.54 ppm) were also observed for
NH, while two of the signals of the butyl group showed
small differences in chemical shift for each epimer. A
resonance at 173.3 ppm in the 13C-NMR spectrum and
a strong absorption at 1729 cm−1 in the infrared
spectrum confirmed the presence of the ester carbonyl
group. Mass spectroscopy showed the molecular for-
3.1. 2-(Trimethylsilylethynyl)aniline (4)
A mixture of 2-iodoaniline (3.303 g, 15.08 mmol),
trimethylsilylethyne (2.60 ml, 18.40 mmol), CuI (15 mg,
0.079 mmol) and PdCl2(PPh3)2 (0.216 g, 0.308 mmol) in
Et2NH (40 ml) was heated to 30°C under nitrogen in a
sealed pressure vessel for 41 h. The solvent was re-
moved in vacuo, the residue was extracted into Et2O,
and the organic layer was washed with water and dried
(MgSO4). Column chromatography (hexanes–Et2O,
9:1) gave 2-(trimethylsilylethynyl)aniline (4) (2.156 g,
76%) [15] as a pale yellow oil. IR (cm−1): wmax 3479
(NH), 3384 (NH), 2959 (CHaliphatic), 2147 (CꢀC), 1614
mula to be C39H47NO4 (M+ 593.3501), the base peak
’
’
at m/z 493 corresponding to the loss of BuOCO from
the molecular ion.
The ferrocenylalkynyl anilinocarbene 18 was synthe-
sised by the aminolysis of the acetyloxycarbene 12 with
2-(ferrocenylethynyl)aniline (8). Thermolysis of 18 in
dibutyl ether at 85°C gave 2-[13%-(12%,19%-dimethoxy-
podocarpa-8%,11%,13%-triene)]-a-(ferrocenylmethyl)-1H-
1
(CꢂC), 1250 (CꢁSi), 843 (CꢁSi). H-NMR: l 0.26 (s,
Si(CH3)3), 4.20 (bs, NH2), 6.69 (td, J=7.8, 1.1 Hz,
H(4)), 6.72, (d, J=7.8 Hz, H(6)), 7.15 (td, J=7.8, 1.6
Hz, H(5)), 7.31 (dd, J=7.8, 1.7 Hz, H(3)). 13C-NMR: l

136
P.D. Woodgate, H.S. Sutherland / Journal of Organometallic Chemistry 629 (2001) 131–144
0.11 (Si(CH3)3), 99.7 (CꢀCSiMe3), 101.8 (CꢀCSiMe3),
107.7 (C(2)), 114.1 (C(6)), 117.7 (C(4)), 129.8 (C(5)),
132.2 (C(3)), 148.2 (C(1)).
for a further 23 h. Workup and chromatography (hex-
anes–Et2O, 9:1) gave 2-(3%,3%-dimethylbutynyl)aniline
(6) (0.841 g, 95%) as tan crystals, m.p. 42–43°C.
Found: M+ 173.1207. Calc. for C12H15N: 173.1204. IR
’
3.2. 2-(Ethynyl)aniline (3)
(cm−1): wmax 3478 (NH), 3383 (NH), 3056 (CHaromatic),
1
2966 (CHalkyl), 1613 (CꢂC), 784, 749, 693 (CH). H-
A solution of KOH (0.403 g, 7.18 mmol) in water (5
NMR: l 1.34 (s, CH3), 4.11 (bs, NH2), 6.65 (td, J=7.8,
1.1 Hz, H(4)), 6.67 (d, J=7.7 Hz, H(6)), 7.06 (td,
J=7.8, 1.5 Hz, H(5)), 7.23 (dd, J=7.8, 1.5 Hz, H(3)).
13C-NMR: l 28.2 (C(CH3)3), 31.2 (C(CH3)3), 75.4
(CꢀCtBu), 104.09 (CꢀCtBu), 108.8 (C(2)), 114.0 (C(6)),
ml) was added to
a solution of 2-(trimethylsi-
lylethynyl)aniline (4) (0.835 g, 4.41 mmol) in MeOH (10
ml) and then stirred at room temperature (r.t.) for 3 h.
The solvent was removed in vacuo and the residue was
extracted into CH2Cl2, washed with water and dried
(MgSO4). The crude product was distilled, b.p. 90°C/10
mmHg (Kugelrohr) (lit. b.p. [23] 98–100°C/12 mmHg),
to give 2-(ethynyl)aniline (3) (0.372 g, 72%) as a colour-
less oil. IR (cm−1): wmax 3471 (NH), 3387 (NH), 3279
(CHalkynyl), 3075 (CHaryl), 3030 (CHaryl), 2096 (CꢀC),
117.8 (C(4)), 128.7 (C(5)), 131.8 (C(3)), 147.4 (C(1)).
+
’
MS; m/z: 173 [80, M ], 158 [100, M−Me ], 143 [42,
+
’
158−Me ], 118 (31), 57 [25, (CH3)3C ], 41 (22).
3.5. 2-(Heptyn-1-yl)aniline (7)
1
1614 (CꢂC), 751 (CH). H-NMR: l 3.38 (s, CꢀCH),
A mixture of 2-iodoaniline (1.099 g, 5.02 mmol),
1-heptyne (0.78 ml, 5.95 mmol), CuI (11 mg, 0.06
mmol) and PdCl2(PPh3)2 (72 mg, 0.10 mmol) in Et2NH
(15 ml) was heated to 30°C under nitrogen in a sealed
pressure vessel for 24 h. Workup and chromatography
(hexanes–Et2O, 9:1) gave 2-(heptyn-1-yl)aniline (7)
4.23 (bs, NH2), 6.67 (t, J=7.8 Hz, H(4)), 6.69 (d,
J=7.8 Hz, H(6)), 7.14 (td, J=7.8, 1.5 Hz, H(5)), 7.30
(dd, J=7.8, 1.5 Hz, H(3)). 13C-NMR: l 80.6 (CꢀCH),
82.4 (CꢀCH), 106.5 (C(2)), 114.2 (C(6)), 117.7 (C(4)),
130.1 (C(5)), 132.5 (C(3)), 148.5 (C(1)).
(0.921 g, 98%) as a pale brown oil. Found: M+
,
’
3.3. 2-(Phenylethynyl)aniline (5)
187.1354. Calc. for C13H17N: 187.1361. IR (cm−1): wmax
3476 (NH), 3380 (NH), 3028 (CHaromatic), 2930
(CHalkyl), 2859 (CHalkyl), 2221 (CꢀC), 1613 (CꢂC), 747
(CH). 1H-NMR: l 0.92 (t, J=7.2 Hz, H(7%)), 1.37
(sextet, J=7.4, 1.1 Hz, H(6%)), 1.44 (m, H(5%)), 1.63 (p,
J=7.2 Hz, H(4%)), 2.46 (t, J=7.1 Hz, H(3%)), 4.15 (bs,
NH2), 6.66–6.67 (m, H(4), H(6)), 7.07 (td, J=7.6, 1.5
Hz, H(5)), 7.24 (dd, J=7.5, 1.5 Hz, H(6)). 13C-NMR: l
13.9(5) (C(7%)), 19.6 (C(6%)), 22.2 (C(5%)), 28.6 (C(4%)),
31.1 (C(3%)), 76.9 (CꢀCPent), 95.7 (CꢀCPent), 108.92
(C(2)), 114.1 (C(6)), 117.8 (C(4)), 128.7 (C(5)), 131.9(5)
A mixture of 2-iodoaniline (1.97 g, 8.99 mmol),
phenylethyne (1.20 ml, 10.93 mmol), CuI (40 mg, 0.21
mmol) and PdCl2(PPh3)2 (0.130 g, 0.19 mmol) in Et3N
(40 ml) was heated to 40°C under a nitrogen atmo-
sphere in a sealed pressure vessel for 19 h. The solvent
was removed in vacuo, the residue was partitioned
between Et2O and water, and the organic layer was
washed with water and dried (MgSO4). Chromatogra-
phy on silica gel using hexanes eluted phenylethyne,
while hexanes–Et2O (9:1) gave 2-(phenylethynyl)aniline
(5) (1.638 g, 94%) as colourless needles, m.p. 90–91°C
(lit. m.p. [16] 90.5–91.5°C). IR (cm−1): wmax 3465
(NH), 3368 (NH), 2205 (CꢀC), 1612 (CꢂC), 747 (CH),
(C(3)), 147.6 (C(1)). MS; m/z: 187 [85, M+ ], 172 [25,
’
’
’
’
M−Me ], 158 [33, M−Et ], 144 [52, M−Pr ], 132
+
’
(50), 130 [100, M−Bu ], 77 (Ph ).
1
691 (CH). H-NMR: l 4.27 (bs, NH2), 6.67–6.76 (m,
3.6. 2-(Trimethylsilylethynyl)pyridine
H(4), H(6)), 7.14 (td, J=7.7, 1.6 Hz, H(5)), 7.31–7.39
(m, H(3), H(2%), H(4%)), 7.50–7.55 (m, H(3%)). 13C-
NMR: l 85.9 (CꢀCPh), 94.6 (CꢀCPh), 107.8 (C(2)),
114.3 (C(6)), 117.0 (C(4)), 123.24 (C(1%)), 128.2 (C(4%)),
128.3 (C(3%)), 129.6 (C(5)), 131.4 (C(2%)), 132.1 (C(3)),
147.7 (C(1)).
A mixture of 2-bromopyridine (3.165 g, 20.03 mmol),
trimethylsilylethyne (4.2 ml, 30 mmol), CuI (0.214 g,
1.12 mmol) and PdCl2(PPh3)2 (0.400 g, 0.57 mmol) in
Et3N (40 ml) was heated to 40°C under nitrogen in a
sealed pressure vessel for 43.5 h. Workup and chroma-
tography (hexanes–Et2O, 3:1) gave 2-(trimethylsilyl-
ethynyl)pyridine (3.205 g, 91%) [18] as a pale yellow oil.
IR (cm−1): wmax 3303 (CHalkynyl), 3053 (CHaryl), 2959
(CHalkyl), 2167 (CꢀC), 1582, 1562 (CꢂC), 1250 (CꢁSi),
3.4. 2-(3%,3%-Dimethylbutynyl)aniline (6)
A mixture of 3,3-dimethylbutyne (0.90 ml, 6.58
mmol), 2-iodoaniline (1.125 g, 5.14 mmol), CuI (10 mg,
0.053 mmol) and PdCl2(PPh3)2 (72 mg, 0.10 mmol) in
Et3N (15 ml) was stirred at r.t. under a nitrogen atmo-
sphere in a sealed pressure vessel. CuI (110 mg, 0.58
mmol) was added after 25 h as the reaction had not
gone to completion, and stirring was continued at r.t.
1
845 (CꢁSi). H-NMR: l 0.26 (s, Si(CH3)3), 7.20 (ddd,
J=7.8, 4.9, 1.1 Hz, H(5)), 7.44 (dt, J=7.8, 0.9 Hz,
H(3)), 7.62 (td, J=7.8, 1.8 Hz, H(4)), 8.56 (ddd, J=
4.9, 1.6, 0.8 Hz, H(6)). 13C-NMR: l −0.3 (Si(CH3)3),
94.7 (CꢀCSiMe3), 103.6 (CꢀCSiMe3), 123.0 (C(6)),
127.2 (C(4)), 136.0 (C(5)), 143.0(5) (C(2)), 149.9 (C(3)).

P.D. Woodgate, H.S. Sutherland / Journal of Organometallic Chemistry 629 (2001) 131–144
137
3.7. 2-Ethynylpyridine
Et2NH (15 ml) was heated to 30°C under nitrogen in a
sealed pressure vessel for 18.5 h; no reaction occurred.
CuI (220 mg, 1.16 mmol) was added and the solution
was heated to 60°C for 24 h. The reaction mixture was
adsorbed onto silica gel and the solvent was removed in
vacuo. Column chromatography followed by radial
chromatography (CH2Cl2) gave 2-(ferrocenyl)ethynyl-
aniline (8) (1.500 g, 99%) as a red solid. Recrystallisa-
tion of a small portion of the product from hexanes–
CH2Cl2 gave small red needles, m.p. (dec., darkens at
A solution of potassium hydroxide (0.663 g, 11.8
mmol) in water (10 ml) was added to a solution of
2-(trimethylsilylethynyl)pyridine (401) (1.500 g, 8.56
mmol) in MeOH (12 ml) at r.t. After 3.5 h the solution
was extracted with Et2O, washed twice with water, and
dried (MgSO4). Removal of the solvent in vacuo gave a
pale yellow oil. Kugelrohr distillation (35°C, 2 mmHg)
gave 2-ethynylpyridine (0.714 g, 81%) [18] as a colour-
less oil. IR (cm−1): wmax 3293 (CHalkynyl), 3053
(CHaromatic), 2109 (CꢀC), 780. 1H-NMR: l 3.15 (s,
H(alkynyl)), 7.26 (td, J=7.7, 4.9, 1.3 Hz, H(5)), 7.48 (dt,
J=7.8, 1.0 Hz, H(3)), 7.66 (td, J=7.7, 1.8 Hz, H(4)),
8.59 (ddd, J=4.9, 1.6, 0.9 Hz, H(6)). 13C-NMR: l 76.9
(CꢀCH), 82.4 (CꢀCH), 123.1 (C(6)), 127.1 (C(4)), 135.9
(C(5)), 141.9 (C(2)), 149.6 (C(3)).
80°C), 120°C. Found: M+ 301.0547. Calc. for
’
C18H15FeN: 301.0554. IR (cm−1): wmax 3432 (NH),
3378 (NH), 2199 (CꢀC), 1612 cm−1 (CꢂC). 1H-NMR: l
(C6D6) 3.78 (bs, NH2), 3.88 (s, Cp (minor rotamer)),
3.93 (t, J=1.8 Hz, H(2%)), 4.06 (s, Cp (major)), 4.34 (t,
J=1.9 Hz, H(3%) (minor)), 4.40 (t, J=1.8 Hz, H(3%)
(major)), 6.33 (dd, J=8.4, 0.7 Hz, H(6)), 6.56 (td,
J=7.5, 1.1 Hz, H(4)), 6.96 (ddd, J=8.4, 7.5, 1.5 Hz,
H(5) (major)), 7.23 (m, H(5) (minor)), 7.45 (dd, J=7.8,
1.5 Hz, H(3) (minor)), 7.65 (bdd, J=6.4, 2.6, H(3)
(major)). 13C-NMR: l 65.3 (C(1%)), 65.9 (C(1%)), 68.8
(C(2%)), 69.5 (Cp), 70.0 (Cp), 71.4 (C(3%)), 82.0 (CꢀCFc),
93.5 (CꢀCFc), 98.8 (CHminor), 108.7 (C(2)), 110.3
(CHminor), 114.2 (C(6)), 117.9 (C(4)), 119.8 (CHminor),
120.0 (CHminor), 121.4 (CHminor), 129.1 (C(5)), 131.9
(C(3)), 147.5 (C(1)). MS; m/z: 301 [100, M+].
3.8. 2-(2%-Pyridyl)ethynylaniline (9)
(A) A mixture of 2-ethynylpyridine (0.477 g, 4.63
mmol), 2-iodoaniline (0.833 g, 3.80 mmol), CuI (60 mg,
0.32 mmol) and PdCl2(PPh3)2 (50 mg, 0.071 mmol) in
Et3N (10 ml) was heated at 40°C under nitrogen in a
sealed pressure vessel for 22 h. Workup and chro-
matography
(hexanes–Et2O,
1:1)
gave
2-(2%-
pyridyl)ethynylaniline (9) (0.254 g, 34%) as fine tan
needles, m.p. 104–106°C. Found: M+ 194.0840. Calc.
’
for C13H10N: M, 194.0844. IR (Nujol, cm−1): wmax 3376
(NH), 3306 (NH), 3192 (CHaryl), 2208 (CꢀC), 1639
3.10. Benzyltriethylammonium pentacarbonyl[(oxo)-
(13-(12,19-dimethoxypodocarpa-8,11,13-triene))-
carbene]chromium (11)
1
(C=C), 773, 743, 736 (CHaryl). H-NMR: l 4.39 (bs,
NH2), 6.70 (td, J=7.8, 1.1 Hz, H(4)), 6.72 (d, J=7.8
Hz, H(6)), 7.17 (td, J=7.8, 1.6 Hz, H(5)), 7.24 (ddd,
J=7.8, 4.8, 1.2 Hz, H(5%)), 7.42 (dd, J=7.8, 1.6 Hz,
H(3)), 7.52 (dd, J=7.8, 1.1 Hz, H(3%)), 7.68 (td, J=7.8,
1.8 Hz, H(4%)), 8.61 (ddd, J=4.9, 1.6, 0.8 Hz, H(6%)).
13C-NMR: l 86.2 (CꢀCPy), 94.0(5) (CꢀCPy), 106.6
(C(2)), 114.4 (C(6)), 117.8 (C(4)), 122.6 (C(6%)), 127.0
(C(4%)), 130.5 (C(5)), 132.6 (C(3)), 136.2 (C(5%)), 143.6
(C(2%)), 148.5 (C(1)), 150.0 (C(3%). MS; m/z: 194 [100,
M+], 193 [35, M−H].
(B) A solution of 2-iodoaniline (0.855 g, 3.90 mmol),
2-ethynylpyridine (0.444 g, 4.31 mmol), CuI (69 mg,
0.36 mmol) and PdCl2(PPh3)2 (53 mg, 0.076 mmol) in
Et3N (40 ml) was stirred under nitrogen in a sealed
pressure vessel at r.t. in a foil-covered flask for 45 h.
Workup followed by chromatography gave (i) 2-
Butyllithium (1.63 ml, 2.5 mol l−1) was added to a
solution
of
13-bromo-12,19-dimethoxypodocarpa-
8,11,13-triene [24] (1.5 g, 4.08 mmol) in THF (12 ml) at
−78°C under nitrogen. The solution was transferred
via cannula to a slurry of Cr(CO)6 in Et2O (20 ml) at
0°C under nitrogen. The mixture was stirred at 0°C for
1.25 h, then the solvent was removed in vacuo to give
crude lithium pentacarbonyl[(oxo)(13-(12,19-dimeth-
oxypodocarpa-8,11,13-triene))carbene]chromium (10).
The salt 10 was dissolved in nitrogen-degassed water
(30 ml) and a solution of benzyltriethylammonium
chloride in nitrogen-degassed water (10 ml) was added,
producing a yellow precipitate. The suspension was
stirred for 1 h, followed by extraction into CH2Cl2.
Workup gave benzyltriethylammonium pentacarbony-
l[(oxo)(13-(12,19-dimethoxypodocarpa-8,11,13-triene))-
carbene]chromium (11) (2.099 g, 78%) as a yellow
foam. IR (cm−1): wmax 2031 (s, CꢀO), 1943 (sh, CꢀO),
iodoaniline
(51
mg,
6%)
and
(ii)
2-(2%-
pyridyl)ethynylaniline (9) (0.489 g, 65%).
3.9. 2-(Ferrocenyl)ethynylaniline (8)
1
1897 (br, CꢀO). H-NMR: l 1.01 (s, H(18)), 1.13 (s,
H(20)), 0.90–1.85 (m, H(1ax), H(2ax), H(2eq), H(3ax),
H(6ax), CH3CH2N)), 1.80–2.00 (m, H(3eq),H(6eq)),
2.21 (bd, J=9.9 Hz, H(1eq)), 2.60–2.90 (m, H(7ax),
A mixture of 2-iodoaniline (1.108 g, 5.06 mmol),
ethynylferrocene (1.160 g, 5.52 mmol) [17], CuI (11 mg,
0.058 mmol) and PdCl2(PPh3)2 (70 mg, 0.10 mmol) in

138
P.D. Woodgate, H.S. Sutherland / Journal of Organometallic Chemistry 629 (2001) 131–144
Hz, H(6%)), 6.91 (td, J=7.7, 1.2 Hz, H(4%)), 6.99 (td,
J=7.7, 1.2 Hz, H(4%)), 7.07 (bt, J=7.4 Hz, H(5%)), 7.09
(bt, J=7.4 Hz, H(5%)), 7.45 (bd, J=7.7 Hz, H(3%)),
10.06 (bs, NH(Z)), 10.89 (bs, NH(E)). 13C-NMR: l 0.27
(SiMe3), 19.1(5) (C(2)), 19.3 (C(6)), 25.6 (C(20)), 25.7
(C(20)), 27.6 (C(18)), 30.2 (C(7)), 30.4 (C(7)), 35.9
(C(3)), 37.9(5) (C(10)), 38.0(3) (C(4)), 38.9 (C(1)), 39.1
(C(1)), 50.9 (C(5)), 51.3 (C(5)), 54.9 (12-OMe), 59.4
(19-OMe), 75.8 (C(19)), 98.8 (CꢀCSiMe3), 103.8
(CꢀCSiMe3), 106.4 (C(11)), 117.5 (C(6%)), 117.6 (C(6%)),
117.7 (C(2%)), 121.3(8) (C(14)), 121.4(2) (C(14)), 123.2(7)
(C(4%)), 123.3(4) (C(4%)), 126.8 (C(13)), 126.9 (C(13)),
126.9(6) (C(13)), 127.0 (C(13)), 128.3 (C(5%)), 128.6
(C(5%)), 129.9 (C(5%)), 132.2 (C(3%)), 132.6 (C(3%)), 136.8
(C(8)), 137.0 (C(8)), 140.5 (C(1%)), 147.7 (C(9)), 150.5
(C(12)), 150.6 (C(12)), 217.1 (CꢀOcis), 224.1 (CꢀOtrans),
289.0 (Ccarbene), 289.1 (Ccarbene). FABMS; m/z: 679 [4,
M+], 651 [3, M−CO], 609 (8), 539 [100, M−5CO],
H(7eq)), 3.10–3.40 (b, CH3CH2N), 3.20 (d, J=9.0 Hz,
H(19)), 3.32 (s, 19-OMe), 3.53 (d, J=9.0 Hz, H(19)),
3.66 (s, 12-Ome), 4.30 (bs, CH2Ph), 6.29 (s, H(11)), 6.58
(s, H(14)), 7.10–7.60 (b, Ph). 13C-NMR:
l 8.1
(CH3CH2N), 19.2 (C(2)), 19.4 (C(6)), 25.6 (C(20)), 27.6
(C(18)), 30.5 (C(7)), 35.9 (C(3)), 37.7(5) (C(4)), 38.0
(C(10)), 39.1 (C(1)), 51.5 (C(5)), 52.8(5) (CH3CH2N),
55.0 (12-OMe), 59.4 (19-OMe), 61.1 (CH2Ph), 75.9
(C(19)), 108.6 (C(11)), 120.8 (C(14)), 126.0 (C(13)),
126.5 (Cpara), 129.5 (Cortho), 131.0 (C(8)), 132.2 (Cmeta),
147.2 (Cipso), 148.3 (C(9)), 150.0 (C(12)), 222.2 (CꢀOcis),
228.6 (CꢀOtrans), 300.3 (Ccarbene).
3.11. Pentacarbonyl[(2-(trimethylsilylethynyl)-
phenylamino)(13-(12,19-dimethoxypodocarpa-
8,11,13-triene))carbene]chromium (13)
Acetyl bromide in CH2Cl2 (0.96 ml, 0.152
g
’
’
CH3COBr per ml) was added to a solution of the
benzyltriethylammonium acylate 12 (0.783 g, 1.19
mmol) in CH2Cl2 (15 ml) at −30°C in a foil-covered
flask under nitrogen. The solution was stirred at −
30°C for 1 h and then cooled to −78°C. A solution of
2-(trimethylsilylethynyl)aniline (4) (0.222 g, 1.27 mmol)
and Et3N (190 ml, 1.36 mmol) in CH2Cl2 (10 ml) was
added to the acetyloxycarbene and the mixture was
held at −78°C for 2.5 h, then warmed slowly to r.t.
The mixture was filtered, the solvent was removed from
the filtrate, and the residue was adsorbed onto silica
gel. Flash chromatography (hexanes–Et2O, 2:1) gave
pentacarbonyl[(2 - (trimethylsilylethynyl)phenylamino)-
(13 - (12,19 - dimethoxypodocarpa - 8,11,13 - triene))-
523 [539−Me −H ], 504 (24), 486 [18, M−
’
Cr(CO)5−H ].
3.12. Pentacarbonyl[(2-(ethynyl)phenylamino)-
(13-(12,19-dimethoxypodocarpa-8,11,13-triene))-
carbene]chromium (14)
Acetyl bromide in CH2Cl2 (0.95 ml, 0.152 g of
CH3COBr per millilitre, 1.17 mmol) was added to a
solution of the benzyltriethylammonium acylate 12
(0.769 g, 1.17 mmol) in CH2Cl2 (15 ml) cooled to
−30°C in a foil-covered flask under nitrogen. The
solution was stirred at −30°C for 1 h then cooled to
−78°C. A solution of 2-ethynylaniline (3) (0.140 g,
1.20 mmol) and Et3N (170 ml, 1.22 mmol) in CH2Cl2
(10 ml) was added to the acetyloxycarbene solution and
the mixture was held at −78°C for 2.5 h then warmed
slowly to r.t. Removal of solvent followed by flash
chromatography (hexanes–Et2O, 2:1) gave pentacar-
bonyl[(2 - (ethynyl)phenylamino)(13 - (12,19 - dimethoxy-
podocarpa - 8,11,13 - triene))carbene]chromium (14)
(0.477 g, 67%) (E/Z ratio 1.9:1) as a yellow foam.
carbene]chromium (13) (0.680 g, 84%) (E/Z ratio
’
1.75:1) as
a
yellow–orange foam. Found: M+
679.2095. Calc. for C36H41CrNO7Si: 679.2057. IR
(cm−1): wmax 2158 (br, CꢀC), 2053 (s, CꢀO), 1976 (sh,
CꢀO), 1926 (br, CꢀO), 1251 (s, CꢁSi), 1110 (s, CꢁOꢁC),
1
845 (s, CꢁSi). H-NMR: l 0.28 (s, SiMe3(Z)), 0.33 (s,
SiMe3(E)), 1.01 (m, H(3ax)), 1.02 (s, H(18)(E)), 1.03 (s,
H(18)(E)), 1.06 (H(18)(Z)), 1.09 (s, H(18)(E)), 1.15 (s,
H(20)(E)), 1.23 (s, H(20)(Z)), 1.42 (dd, J=12.9, 1.8 Hz,
H(5)), 1.43 (ddd, J=13.2, 13.2, 4.0 Hz, H(1ax)), 1.54–
1.73 (m, H(2ax), H(2eq), H(6ax)), 1.83–1.94 (m,
H(3eq), H(6eq)), 2.19 (dd, J=12.7, 2.7 Hz, H(1eq)(E)),
2.29 (bd, J=13.0 Hz, H(1eq)(Z)), 2.53–2.75 (m,
H(7ax)), 2.80 (bdd, J=16.6, 5.7 Hz, H(7eq)(E)), 2.84
(bdd, J=16.6, 6.0 Hz, H(7eq)(Z)), 3.21 (d, J=9.0 Hz,
H(19)), 3.23 (d, J=9.0 Hz, H(19)), 3.31(7) (s, 19-
OMe(E)), 3.32(2) (s, 19-OMe(E)), 3.34 (s, 19-OMe(Z)),
3.48 (d, J=9.0 Hz, H(19)), 3.51 (d, J=9.0 Hz, H(19)),
3.67(3) (s, 12-OMe(E)), 3.69(4) (s, 12-OMe(E)), 3.77 (s,
12-OMe(Z)), 3.84 (s, 12-OMe(Z)), 6.36 (d, J=8.2 Hz,
H(6%)), 6.55 (bd, J=8.2 Hz, H(6%)), 6.58 (bs, H(11),
H(14)), 6.61 (bd, J=8.2 Hz, H(6%)), 6.68 (bd, J=8.2
Found: M+
, 607.1678. Calc. for C33H33CrNO7:
’
607.1662. IR (cm−1): wmax 2054 (s, CꢀO), 1976 (sh,
1
CꢀO), 1925 (br, CꢀO). H-NMR: l 1.01 (m, H(3ax)),
1.02 (s, H(18)), 1.03 (s, H(18)), 1.06 (s, H(18)), 1.08 (s,
H(18)), 1.16 (H(20)), 1.19 (s, H(20)), 1.23 (s, H(20)),
1.40–1.48 (m, H(5), H(1ax)), 1.52–1.80 (m, H(2ax),
H(2eq), H(6ax)), 1.85–2.03 (m, H(3eq), H(6eq)), 2.13–
2.25 (m, H(1eq)), 2.51–2.91 (m, H(7ax), H(7eq)), 3.21–
3.28 (m, H(19)), 3.31(7) (19-OMe(Z)), 3.32(3) (s,
19-OMe(Z)), 3.34 (s, 19-OMe(E)), 3.35 (s, 19-OMe(E)),
3.56 (d, J=9.2 Hz (H(19)), 3.59 (s, 12-OMe), 3.60 (s,
12-OMe), 3.77 (s, 12-OMe), 3.84 (CꢀCH), 6.41 (d,
J=8.6 Hz, H(6%)), 6.57 (bd, J=7.6 Hz, H(6%)), 6.57 (s,

P.D. Woodgate, H.S. Sutherland / Journal of Organometallic Chemistry 629 (2001) 131–144
139
H(2ax), H(6ax), H(2eq)), 1.82–1.92 (m, H(3eq)), 1.96
(ddt, J=13.4, 7.2, 1.9 Hz, H (6eq)), 2.18 (bd, J=12.6
Hz, H(1eq)), 2.27 (bd, J=12.8 Hz, H(1eq)), 2.53–2.82
(m, H(7ax), H(7eq)), 2.87 (bdd, J=17.1, 6.8 Hz,
H(7eq)), 3.20–3.26 (m, H(19)), 3.31(5) (s, 19-OMe),
3.32(3) (s, 19-OMe), 3.33(1) (s, 19-OMe), 3.34 (s, 19-
OMe), 3.48 (d, J=9.1 Hz, H(19)), 3.54 (d, J=9.1 Hz,
H(19)), 3.62 (s, 12-OMe), 3.63 (s, 12-OMe), 3.77 (s,
12-OMe), 6.25(0) (s, H(14)), 6.25(4) (s, H(14)), 6.25(7)
(s, H(14)), 6.26 (s, H(14)), 6.35 (d, J=7.6 Hz, H(6%)),
6.54 (d, J=8.0 Hz, H(6%)), 6.57(5) (s, H(11)), 6.58 (s,
H(11)), 6.61 (d, J=8.2 Hz, H(6%)), 6.65(7) (J=8.4 Hz,
H(6%)), 6.66 (d, J=8.4 Hz, H(6%)), 6.80 (m, H(4%)), 6.85
(td, J=8.2, 1.4 Hz, H(4%)), 6.93 (d, J=8.4 Hz, H(4%)),
7.06 (td, J=7.3, 1.3 Hz, H(5%)), 7.11 (td, J=7.2, 1.1
Hz, H(5%)), 7.31 (dd, J=7.9, 0.7 Hz, H(3%)), 7.38 (dd,
J=7.7, 1.7 Hz, H(3%)), 7.53 (d, J=7.8, 0.7 Hz, H(3%)),
10.05 (b, NH(E)), 10.81 (b, NH(Z)). 13C-NMR: l 19.2
(C(2)), 19.2(8) (C(6)), 19.3(4) (C(6)), 25.6 (C(20)), 25.7
(C(20)), 27.5(6) (C(CH3)3), 27.6(3) (C(18)), 30.1(3)
(C(7)), 30.3 (C(7), C(CH3)3), 30.8(5) (C(CH3)3), 30.9(5)
(C(CH3)3), 35.9 (C(3)), 36.0 (C(3)), 38.0 (C(10)),
38.0(5) (C(10)), 38.9 (C(4)), 39.0 (C(1)), 39.1 (C(1)),
50.9 (C(5)), 51.2(6) (C(5)), 51.3 (C(5)), 54.9 (12-OMe),
55.2(5) (12-OMe), 59.4 (19-OMe), 73.8 (CꢀCtBu), 75.9
(C(19)), 76.0 (C(19)), 93.9 (CꢀCtBu), 110.3 (C(11)),
110.9 (C(11)), 118.3 (C(2%)), 119.6 (C(6%)), 119.9
H(14)), 6.63 (bd, J=7.7 Hz, H(6%)), 6.65 (s, H(14)),
6.65 (d, J=8.4 Hz, H(6%)), 6.66 (d, J=8.4 Hz, H(6%)),
6.80(1) (s, H(11)), 6.80(6) (s, H(11)), 6.81(3) (s, H(11)),
6.96 (t, J=8.2 Hz, H(4%)), 7.02 (td, J=8.2, 1.5 Hz,
H(4%)), 7.09 (td, J=7.8, 1.1 Hz, H(5%)), 7.12 (td, J=
7.9, 1.1 Hz, H(5%)), 7.48 (dd, J=8.0, 2.1 Hz, H(3%)),
7.57 (dd, J=7.9, 1.4 Hz, H(3%)), 7.66 (bd, J=7.9 Hz,
H(3%)), 10.06 (b, NH(Z)), 10.89 (b, NH(E)). 13C-NMR: l
19.1(5) (C(2)), 19.3 (C(6)), 25.5(5) (C(20)), 25.7
(C(20)), 27.6 (C(18)), 30.1 (C(7)), 30.4 (C(7)), 35.9
(C(3)), 38.1 (C(10)), 38.8 (C(4)), 38.9(5) (C(1)), 39.1
(C(1)), 50.9 (C(5)), 51.3 (C(5)), 54.8 (12-OMe), 55.1
(12-OMe), 59.4 (19-OMe), 75.8 (C(19)), 75.9 (C(19)),
78.0 (CꢀCH), 75.9 (CꢀCH), 84.1(5) (CꢀCH), 85.9
(CꢀCH), 106.4 (C(11)), 106.9 (C(11)), 110.3 (C(6%)),
110.9 (C(6%)), 120.0 (C(2%)), 121.3 (C(14)), 121.6
(C(14)), 123.3 (C(4%)), 123.4 (C(4%)), 126.8 (C(13)),
127.1 (C(13)), 127.1(3) (C(13)), 128.7 (C(5%)), 129.5
(C(5%)), 129.8 (C(5%)), 132.3 (C(3%)), 132.7 (C(3%)), 136.5
(C(8)), 141.7 (C(1%)), 143.5 (C(9)), 150.8 (C(12)), 150.9
(C(12)), 216.8 (CꢀOcis), 217.0 (CꢀOcis), 224.0
(CꢀOtrans), 224.9 (CꢀOtrans), 289.3 (Ccarbene). FABMS;
m/z: 607 [2, M+], 579 [4, M−CO], 495 [9, M−4CO],
’
467 [100, M−5CO], 452 [5, 467−Me ], 414 [10,
’
467−Cr−H ].
3.13. Pentacarbonyl[(2-(3,3-dimethylbutynyl)phenyl-
amino)(13-(12,19-dimethoxypodocarpa-8,11,13-triene))-
carbene]chromium (15)
(C(6%)),
(C(14)), 123.3 (C(4%)), 126.7(8) (C(13)), 126.8(5)
(C(13)), 127.0 (C(13)), 127.3 (C(5%)), 128.6
121.0 (C(14)), 121.3
(C(14)), 121.4
(C(5%)), 129.8 (C(5%)), 132.4(0) (C(3%)), 132.4(3) (C(3%)),
135.7 (C(8)), 140.2 (C(1%)), 147.8 (C(9)), 148.7 (C(9)),
150.4 (C(12)), 150.6 (C(12)), 217.2 (CꢀOcis), 223.9
(CꢀOtrans), 287.4 (Ccarbene). FABMS; m/z: 663 [5, M+],
635 [9, M−CO], 593 (14), 551 [16, M−4CO], 523
[100, M−5CO], 507 (56), 488 (34), 472 [23, M−
Acetyl bromide in CH2Cl2 (0.92 ml, 0.152 g of
CH3COBr per millilitre, 1.14 mmol) was added to a
solution of the benzyltriethylammonium acylate 12
(0.745 g, 1.13 mmol) in CH2Cl2 (15 ml) cooled to
−30°C in a foil-covered flask under nitrogen. The
solution was stirred at −30°C for 1 h then cooled to
−78°C. A solution of 2-(3,3-dimethylbutynyl)aniline
(6) (0.200 g, 1.15 mmol) and Et3N (174 ml, 1.25 mmol)
in CH2Cl2 (10 ml) was added to the acetyloxycarbene
solution. The mixture was held at −78°C for 2 h then
warmed slowly to r.t. Removal of the solvent and
adsorption of the residue onto silica gel followed by
flash chromatography (hexanes–Et2O, 1:1) gave pen-
tacarbonyl[(2 - (3,3 - dimethylbutynyl)phenylamino)(13-
(12,19 - dimethoxypodocarpa - 8,11,13 - triene))carbene]-
chromium (15) (0.582 g, 77%) (E/Z ratio 5:1) as an
’
Cr(CO)5+H ].
3.14. Pentacarbonyl[(2-(heptyn-1-yl)phenyl-
amino)(13-(12,19-dimethoxypodocarpa-8,11,13-
triene))carbene]chromium (16)
Acetyl bromide in CH2Cl2 (0.87 ml, 0.152 g of
CH3COBr per millilitre) was added to a solution of the
benzyltriethylammonium acylate 12 (0.703 g, 1.07
mmol) in CH2Cl2 (15 ml) cooled to −30°C in a foil-
covered flask under nitrogen. The solution was stirred
at −30°C for 1 h then cooled to −78°C. A solution of
2-(1%-heptynyl)aniline (7) (0.202 g, 1.08 mmol) and Et3N
(170 ml, 1.22 mmol) in CH2Cl2 (10 ml) was added to the
acetyloxycarbene solution and the mixture was held at
−78°C for 2 h, then warmed slowly to r.t. Removal of
solvent followed by flash chromatography (hexanes–
orange–yellow foam. Found: M+ 663.2319. Calc. for
’
C37H41CrNO7: 663.2288. IR (cm−1): wmax 2054 (s,
CꢀO), 1976 (sh, CꢀO), 1925 (br, CꢀO). 1H-NMR: l
1.01 (m, H(3ax)), 1.01 (s, H(18)), 1.02 (s, H(18)), 1.03
(s, H(18)), 1.20 (s, H(20)), 1.39 (s, (CH3)3C), 1.42(0) (s,
(CH3)3C), 1.42(4) (dd, J=12.4, 1.8 Hz, H(5)), 1.45
(ddd, J=13.0, 13.0, 3.8 Hz, H(1ax)), 1.55–1.74 (m,

140
P.D. Woodgate, H.S. Sutherland / Journal of Organometallic Chemistry 629 (2001) 131–144
Et2O, 1:1) gave pentacarbonyl[(2-(heptyn-1-yl)phenyl-
amino)(13-(12,19-dimethoxypodocarpa-8,11,13-triene))-
carbene]chromium (16) (0.466 g, 64%) as an unstable
yellow–orange oil. IR (cm−1): wmax 2054 (s, CꢀO), 1977
(sh, CꢀO), 1931 (br, CꢀO). Attempts to obtain NMR
spectra in either CDCl3 or C6D6 failed due to decompo-
sition of the product.
(C(11%)), 109.3 (C(3)), 109.4 (C(3)), 110.4 (C(7)), 110.6
(C(7)),118.2 (C(4)), 118.7 (C(4)), 119.0 (C(13%)), 119.1
(C(13%)), 119.4 (C(13%)), 121.4 (C(5)), 122.0 (C(6)), 122.4
(C(6)), 127.3(0) (C(8%)), 127.3(5) (C(8%)), 127.3(9)
(C(3a)), 127.9 (C(3a)), 131.5 (C(2)), 131.7 (C(2)),
131.8(7) (C(14%)), 131.9(4) (C(14%)), 135.4 (C(7a)),
135.9(5) (C(7a)), 151.1 (C(9)), 155.2(5) (C(12)), 172.4
(CꢂO), 173.9 (CꢂO). IR (cm−1); m/z: 589 [64, M+], 532
’
[22, M−Bu ], 517 [100, M−Me2SiꢂCH2], 443 (18), 414
’
3.15. Thermolysis of pentacarbonyl[(2-(trimethylsilyl-
ethynyl)phenylamino)(13-(12,19-dimethoxypodo-
carpa-8,11,13-triene))carbene]chromium (13)
[74, M−Me3SiH−BuOCO ].
3.16. Thermolysis of pentacarbonyl[(2-(3,3-dimethyl-
butynyl)phenylamino)(13-(12,19-dimethoxy-
A
solution of pentacarbonyl[(2-(trimethylsilyl-
ethynyl)phenylamino)(13-(12,19-dimethoxy-podocarpa-
8,11,13-triene))carbene]chromium (13) (0.248 g, 0.364
mmol) in dibutyl ether (7 ml) was freeze–pump–thaw
cycled three times and then heated to 85°C under a
continuous stream of nitrogen for 1.5 h. The solvent
was removed in vacuo and the residue was dissolved in
Me2CO–H2O (2:1 v/v, 15 ml) and stirred at r.t. for 24
h. The product was extracted with Et2O (3×50 ml) and
dried. PLC (hexanes–Et2O, 2:1) then analytical TLC
(hexanes–Et2O, 2:1) gave butyl 2-[13%-(12%,19%-
dimethoxy podocarpa-8%,11%,13%-triene)]-a-(trimethylsi-
lyl)-1H-indole-3-acetate (20) (29.2 mg, 14%) as a
podocarpa-8,11,13-triene))carbene]chromium (15)
3.16.1. In dibutyl ether
A
solution of pentacarbonyl[(2-(3,3-dimethylbu-
tynyl)phenylamino)(13 - (12,19 - dimethoxy - podocarpa-
8,11,13-triene))carbene]chromium (15) (0.222 g, 0.335
mmol) in dibutyl ether (6 ml) was freeze–pump–thaw
cycled three time and then heated to 90°C under a
continuous flow of nitrogen for 2 h. The mixture was
filtered and the solvent was removed to give a orange
oil which was dissolved in Et2O–water (2:1 v/v, 30 ml)
and photolysed under air for 18 h using a Wotan
sunlamp. The greenish yellow solution was diluted with
Et2O and washed with water. PLC (hexanes–Et2O, 2:1;
two elutions) followed by analytical TLC (hexanes–
Et2O, 1:1 then 2:1, two elutions) failed to improve
product purity. Mass spectroscopy showed that butyl
2-[13%-(12%,19%-dimethoxypodocarpa-8%,11%,13%-triene)]-a-
(1,1-dimethylethyl)-1H-indole-3-acetate (23) was one
component of the mixture.
colourless oil. Found: M+
, 589.3580. Calc. for
’
C36H51NO4Si: 589.3587. IR (cm−1): wmax 3369 (br,
1
NH), 1730 (CꢂO), 1254 (CꢁSi), 850 (CꢁSi). H-NMR: l
0.05, s, Me3Si), 0.06 (s, Me3Si), 0.89 (t, J=7.4 Hz,
CH3CH2), 0.93 (t, J=7.4 Hz, CH3CH2), 1.04 (m,
H(3%ax)), 1.06(5) (s, H(18%)), 1.07(2) (s, H(18%)), 1.26(4)
(s, H(20%)), 1.26(9) (s, H(20%)), 1.35 (sextet, J=7.3 Hz,
CH3CH2CH2), 1.38 (sextet, J=7.4 Hz, CH3CH2CH2),
1.49 (dd, J=10.9, 2.0 Hz, H(5%)), 1.51 (dd, J=10.9, 1.8
Hz, H(5%)), 1.60–1.80 (m, H(1%ax), H(2%ax), H(2%eq),
H(6%ax)), 1.65 (p, J=7.4 Hz, CH3CH2CH2CH2), 1.91
(bd, J=13.7 Hz, H(3%eq)), 2.02 (bdd, J=13.2, 6.8 Hz,
H(6%eq)), 2.33 (bd, J=12.5 Hz, H(1%eq)), 2.75–2.96 (m,
H(7%ax), H(7%eq)), 3.27 (d, J=9.1 Hz, H(19%)), 3.35 (s,
19%-OMe), 3.56 (d, J=9.1 Hz, H(19%)), 3.74 (s, 12%-
OMe), 3.78 (s, CHCO2Bu), 3.79(6) (s, CHCO2Bu),
3.80(4) (s, 12%-OMe), 4.07–4.16 (m, OCH2CH2), 6.88 (s,
H(11%)), 6.90 (s, H(11%)), 7.00(9) (s, H(14)), 7.01 (s,
H(14)), 7.06 (td, J=8.1, 1.1 Hz, H(5)), 7.11 (td, J=
8.1, 1.1 Hz, H(5)), 7.13 (td, J=8.2, 1.2 Hz, H(6)), 7.18
(td, J=8.1, 1.2 Hz, H(6)), 7.29 (bd, J=8.0 Hz, H(7)),
7.35 (bd, J=8.0 Hz, H(7)), 7.66 (bd, J=7.7 Hz, H(4)),
7.80 (bd, J=8.0 Hz, H(4)), 8.19 (bs, NH). 13C-NMR: l
−0.68, Me3Si), 13.7 (CH3CH2), 19.2 (C(2%)), 19.3
(C(6%)), 25.6 (C(20%)), 27.6 (C(18%)), 30.1 (C(7%)), 30.7
(CH3CH2), 30.9 (CH3CH2CH2), 31.7 (CH3CH2), 36.0
(C(3%)), 36.5(8) (CHCO2Bu), 36.6(4) (CHCO2Bu), 38.1
(C(10%)), 38.2 (C(4%)), 39.0 (C(1%)), 51.3 (C(5%)), 55.6
(12%-OMe), 55.8 (12%-OMe), 59.4 (19%-OMe), 64.0
(CH2OCO), 64.6 (CH2OCO), 75.9 (C(19%)), 107.7
3.16.2. In toluene
A
solution of pentacarbonyl[(2-(3,3-dimethylbu-
tynyl)phenylamino)(13 - (12,19 - dimethoxypodocarpa-
8,11,13-triene))carbene]chromium (15) (0.168 g, 0.253
mmol) in C6H5Me (10 ml) was freeze–pump–thaw
cycled three times and then heated to 85°C for 2 h
under a continuous flow of nitrogen. Removal of the
solvent gave a orange oil which was dissolved in Et2O
and photolysed under air in sunlight. The colourless
solution was filtered and PLC (hexanes–Et2O, 1:1) gave
2-[13%-(12%,19%-dimethoxypodocarpa-8%,11%,13%-triene)]-a-
(1,1-dimethylethyl)-1H-indole-3-acetic acid (24) (22.1
mg, 17%) as a colourless glass. Found: M+ , 517.3191.
’
Calc. for C33H43NO4: 517.3192. IR (cm−1): wmax 1705
(CꢂO). 1H-NMR: l 0.96 (s, C(CH3)3), 1.04 (m,
H(3%ax)), 1.07 (s, H(18%)), 1.08 (s, H(18%)), 1.26(7) (s,
H(20%)), 1.27 (s, H(20%)), 1.49 (bd, J=12.7 Hz, H(5%)),
1.54 (ddd, J=13.0, 13.0, 3.6 Hz, H(1%ax)), 1.60–1.80
(m, H(2%ax), H(2%eq), H(6%ax)), 1.91 (bd, J=13.5 Hz,

P.D. Woodgate, H.S. Sutherland / Journal of Organometallic Chemistry 629 (2001) 131–144
141
H(3%eq)), 2.02 (bdd, J=12.5, 6.6 Hz, H(6%eq)), 2.34 (bd,
J=12.6 Hz, H(1%eq)), 2.80 (ddd, J=16.7, 11.2, 7.3 Hz,
H(7%ax)), 2.92 (bdd, J=16.7, 6.0 Hz, H(7%eq)), 3.28(2)
(d, J=9.0 Hz, H(19%)), 3.28(7) (d, J=9.0 Hz, H(19%)),
3.35(2) (s, 19%-OMe), 3.35(5) (s, 19%-OMe), 3.55 (d,
J=9.1 Hz, H(19%)), 3.63 (s, CHCO2H), 3.65 (s,
CHCO2H), 3.75 (s, 12%-OMe), 6.91 (s, H(11%)), 7.08 (td,
J=7.0, 1.4 Hz, H(5)), 7.09 (s, H(14%)), 7.15 (t, J=7.1
Hz, H(6)), 7.31 (d, J=8.0 Hz, H(7)), 7.76 (bd, J=7.4
Hz, H(4)), 7.88 (dd, J=8.0, 3.3 Hz, H(4), 8.14, bs,
NH), 8.15 (bs, NH), COOH, b, not detected. 13C-
NMR: l 19.1(6) (C(2%)), 19.2(4) (C(6%)), 25.6(2) (C(20%)),
25.6(3) (C(20%)), 27.7 (C(18%)), 28.5 ((CH3)3C), 30.0(7)
(C(7%)), 30.1(0) (C(7%)), 35.7 ((CH3)3C), 36.0 (C(3%)), 38.1
(C(10%)), 38.3 (C(4%)), 39.095 (C(1%)), 51.1 (C(5%)), 51.2
(C(5%)), 52.8(0) (CHCO2H), 52.8(6) (CHCO2H), 55.9(1)
(12%-OMe), 55.9(7) (12%-OMe), 59.4 (19%-OMe), 75.9(2)
(C(19%)), 75.9(6) (C(19%)), 107.7 (C(11%)), 107.8 (C(11%)),
108.9(5) (C(3a)), 109.0(2) (C(3)), 110.5 (C(7)), 119.0
(C(13%)), 119.5(3) (C(4)), 119.5(7) (C(4)), 121.7 (C(5)),
122.3(0) (C(6)), 122.3(5) (C(6)), 127.2 (C(8%)), 128.0
(C(3a)), 132.4 (C(14%)), 134.7(8) (C(2)), 134.8(5) (C(2)),
135.8(6) (C(7a)), 135.9(1) (C(7a)), 152.0 (C(9%)), 154.9
H(19%)), 3.76 (s, 12%-OMe), 6.82 (s, H(11%)), 6.96 (s,
H(14%)), 7.22–7.25 (seven lines), H(6), H(5)), 7.34 (ddd,
J=6.7, 1.7, 0.5 Hz, H(7), 8.35 (three lines), H(4)), 8.69
(bs, NH). 13C-NMR: l 14.0 (CH3CH2), 19.1 (C(2%)),
19.2 (C(6%)), 22.3 (CH3CH2), 24.8 (CH2CH2CO), 25.5
(C(20%)), 27.7 (C(18%)), 30.0 (C(7%)), 31.6 (CH3CH2CH2),
35.9 (C(3%)), 38.0(5) (C(10%)), 38.3 (C(4%)), 39.0(5)
(C(1%)), 41.3 (COCH2), 51.2 (C(5%)), 55.5 (12%-OMe),
59.4 (19%-OMe), 75.9 (C(19%)), 107.2 (C(11%)), 110.5(5)
(C(7)), 115.9(5) (C(3)), 118.8 (C(13%)), 122.0 (C(5),
C(3a)), 122.2 (C(4)), 123.0 (C(6)), 127.3 (C(8%)), 132.4
(C(14%)), 135.0(5) (C(2)), 140.4 (C(7a)), 153.0 (C(9%)),
155.1 (C(12%)), 199.1 (CꢂO). MS; m/z: 501 [49, M+],
’
’
470 [100, M−MeO ], 430 [62, M−C5H11 ].
3.18. Thermolysis of pentacarbonyl[(2-(ethynyl)-
phenylamino)(13-(12,19-dimethoxypodocarpa-
8,11,13-triene))carbene]chromium (14)
A
solution of pentacarbonyl[(2-(ethynyl)phenyl-
amino)(13-(12,19-dimethoxypodocarpa-8,11,13-triene))-
carbene]chromium (14) (0.181 g, 0.298 mmol) in dibutyl
ether (5 ml) was freeze–pump–thaw cycled three times
and then was heated to 85°C under a continuous flow
of nitrogen for 1.5 h. Removal of solvent gave a brown
oil. PLC (hexanes–Et2O, 1:1 and then 2:1, two elutions)
(C(12%)), 155.0 (C(12%)), 175.0 (CꢂO), 175.2 (CꢂO). MS;
+
’
m/z: 517 [22, M ], 460 [100, M−t-Bu ].
gave
2-[13%-(12%,19%-dimethoxypodocarpa-8%,11%,13%-
3.17. Thermolysis of pentacarbonyl[(2-(heptyn-1-yl)-
phenylamino)(13-(12,19-dimethoxy-podocarpa-
8,11,13-triene))carbene]chromium (16)
triene)-3-(pentan-2-one)-1H-indole (27) (9.9 mg, 7%) as
a colourless oil. Found: M+ , 487.3083. Calc. for
’
C32H41NO3: 487.3086. IR (cm−1): wmax 3407 (NH),
1
1705 (CꢂO). H-NMR: l 0.81 (t, J=7.4 Hz, CH3CH2),
A solution of pentacarbonyl[(2-(heptyn-1-yl)phenyl-
amino)(13-(12,19-dimethoxypodocarpa-8,11,13-triene))-
carbene]chromium (16) (0.222 g, 0.328 mmol) in dibutyl
ether (8 ml) was freeze–pump–thaw cycled three times
and then was heated to 85°C under a continuous flow
of nitrogen for 2 h. The solvent was removed and the
residual orange oil was dissolved in Me2CO–H2O (3:1
v/v, 20 ml) and stirred at r.t. for 24 h to oxidise any
chromium residues. The solution was extracted with
CH2Cl2 (80 ml) and washed with water (50 ml). PLC
(hexanes–Et2O, 2:1) gave 2-[13%-(12%,19%-dimethoxy-
podocarpa-8%,11%,13%-triene)]-3-(hexan-1-one)-1H-indole
(25) (71.6 mg, 44%) as a pale orange glass. Found:
1.04 (ddd, J=13.7, 4.3 Hz, H(3%ax)), 1.06 (s, H(18%)),
1.25 (s, H(20%)), 1.47 (dd, J=12.9, 1.8 Hz, H(5%)), 1.49
(ddd, J=13.1, 3.6 Hz, H(1%ax)), 1.53 (sx, J=7.3 Hz,
CH3CH2), 1.62–1.82 (m, H(2%ax), H(2%eq), H(6%ax)),
1.91 (bd, J=13.4 Hz, H(3%eq)), 2.01 (bdd, J=13.3, 7.1
Hz, H(6%eq)), 2.33 (bd, J=12.3 Hz, H(1%eq)), 2.40 (t,
J=7.3 Hz, CH2CH2CO), 2.79 (ddd, J=16.7, 11.4, 7.2
Hz, H(7%ax)), 2.89 (bdd, J=16.7, 5.7 Hz, H(7%eq)), 3.27
(d, J=9.1 Hz, H(19%), 3.35 (s, 19%-OMe), 3.55 (d,
J=9.1 Hz, H(19)), 3.79 (s, 12%-OMe), 3.83 (s,
ArCH2CO), 6.90 (s, H(11)), 7.07 (s, H(14)), 7.12 (td,
J=7.8, 7.5, 0.9 Hz, H(5)), 7.19 (td, J=8.0, 7.5, 1.1 Hz,
H(6)), 7.37 (bd, J=8.0 Hz, H(7)), 7.50 (bd, J=7.8 Hz,
H(4)), 8.61 (bs, NH). 13C-NMR: l 13.7 (CH3CH2), 17.2
(CH3CH2), 19.1(5) (C(2%)), 19.2(5) (C(6%)), 25.5 (C(20%)),
27.6(5) (C(18%)), 30.1 (C(7%)), 35.9 (C(3%)), 38.1 (C(10%)),
38.2 (C(4%)), 39.0 (C(1%)), 40.4 (CH2CH2CO), 43.2
(ArCH2O), 51.2 (C(5%)), 55.7 (12%-OMe), 59.4 (19%-
OMe), 75.9 (C(19%)), 106.7 (C(3)), 107.7 (C(11%)),
110.7(5) (C(7)), 118.3 (C(13%)), 118.6 (C(4)), 119.6
(C(5)), 122.0 (C(6)), 127.6(5) (C(3a), C(8%)), 128.6
(C(2)), 131.2 (C(14%)), 135.5 (C(7a)), 151.3 (C(9%)), 155.0
(C(12%)), 210.3 (CꢂO). MS; m/z: 487 [23, M+], 416 [100,
M+ , 501.3256. Calc. for C33H43NO3: 501.3243. IR
’
1
(cm−1): wmax 3322 (NH), 1667 (CꢂO). H-NMR: l 0.80
(t, J=7.3 Hz, CH3CH2CH2), 1.01–1.16 (m, H(3%ax),
CH3CH2CH2), 1.07 (s, H(18%)), 1.26 (s, H(20%)), 1.45
(dd, J=12.4, 1.8 Hz, H(5%)), 1.46 (ddd, J=12.9, 3.8
Hz, H(1%ax)), 1.56 (p, J=7.4 Hz, PrCH2CH2), 1.64–
1.80 (m, H(2%ax), H(2%eq), H(6%ax)), 1.91 (bd, J=13.5
Hz, H(3%eq)), 2.02 (bdd, J=13.3, 7.1 Hz, H(6%eq)), 2.35
(bd, J=12.5 Hz, H(1%eq)), 2.43 (t, J=7.6 Hz,
ArCOCH2), 2.76 (ddd, J=16.7, 11.4, 7.2 Hz, H(7%ax)),
2.86 (bdd, J=16.7, 5.8 Hz, H(7%eq)), 3.28 (d, J=9.1
Hz, H(19%)), 3.35 (s, 19%-OMe), 3.55 (d, J=9.1 Hz,
’
M−PrCO ], 248 (28).

142
P.D. Woodgate, H.S. Sutherland / Journal of Organometallic Chemistry 629 (2001) 131–144
3.19. Synthesis and thermolysis of pentacarbonyl[(2-
(phenylethynyl)phenylamino)(13-(12,19-dimethoxy-
podocarpa-8,11,13-triene))carbene]chromium (17)
(C(7)), 118.2 (C(13%)), 119.4 (C(4)), 121.4 (C(5)), 121.8
(C(6)), 126.4 (Cpara), 127.3 (C(8%)), 127.5 (C(3a)),
128.0(4) (Cortho), 128.0(7) (Cortho), 128.3 (Cmeta),
128.4(5) (Cmeta), 131.9 (C(14%)), 133.9 (C(2)), 135.8
(Cipso), 139.1 (C(7a)), 139.2 (C(7a)), 151.5 (C(9%)), 155.3
(C(12%)), 173.3 (CꢂO). MS; m/z: 593 [66, M+], 493 [100,
A solution of acetyl bromide in CH2Cl2 (0.277 g of
CH3COBr per millilitre, 0.47 ml, 1.06 mmol) was added
to a solution of the benzyltriethylammonium acylate 12
(0.693 g, 1.05 mmol) in CH2Cl2 (15 ml) at −30°C in a
foil-covered flask under nitrogen. The solution was
stirred at −30°C for 1 h then cooled to −78°C. A
solution of 2-(phenylethynyl)aniline (5) (0.213 g, 1.10
mmol) and Et3N (0.154 ml, 1.10 mmol) in CH2Cl2 (10
ml) was added and the temperature was held at −78°C
for 2 h before warming to r.t. TLC showed that pen-
tacarbonyl[(2 - (phenylethynyl)phenylamino)(13 - (12,19-
’
M−BuOCO ]; and (ii) 2-[13%-(12%,19%-dimethoxypodo-
carpa-8%,11%,13%-triene)]-3-(benzyl)-1H-indole (30) (37
mg, 7%) as a colourless glass. Found: M+ 493.2987.
’
1
Calc. for C34H39NO2: 493.2981. H-NMR: l 1.02 (ddd,
J=13.6, 13.6, 3.9 Hz, H(3%ax)), 1.03 (s, H(18%)), 1.23 (s,
H(20%)), 1.43 (dd, J=12.6, 1.7 Hz, H(5%)), 1.48 (ddd,
J=13.0, 13.0, 3.8 Hz, H(1%ax)), 1.61–1.80 (m, H(2%ax),
H(2%eq), H(6%ax)), 1.89 (bd, J=13.6 Hz, H(3%eq)), 1.95
(bdd, J=13.4, 6.7 Hz, H(6%eq)), 2.31 (bd, J=12.3 Hz,
H(1%eq)), 2.61–2.75 (m, H(7%ax), H(7%eq)), 3.24 (d, J=
9.1 Hz, H(19%)), 3.33 (s, 19%-OMe), 3.53 (d, J=9.1 Hz,
H(19%)), 3.79 (s, 12%-OMe), 4.20 (d, J=16.7 Hz, CHPh),
4.25 (d, J=16.7 Hz, CHPh), 6.88 (s, H(11%)), 7.02 (td,
J=7.4, 0.7 Hz, H(5)), 7.04 (s, H(14%)), 7.14 (bt, J=7.6
Hz, Hpara), 7.16 (td, J=7.0, 1.0 Hz, H(6)), 7.23 (three
lines, Hortho, Hmeta). 7.37 (bd, J=8.1 Hz, H(7)), 7.41
(bd, J=7.9 Hz, H(4)), 8.75 (bs, NH). 13C-NMR: l 19.1
(C(2%)), 19.2 (C(6%)), 25.5 (C(20%)), 27.6 (C(18%)), 30.0
(C(7%)), 31.0 (CH2Ph), 35.9 (C(3%)), 38.0(5) (C(10%)), 38.1
(C(4%)), 39.0 (C(1%)), 51.3 (C(5%)), 55.8 (12%-OMe), 59.4
(19%-OMe), 75.8 (C(19%)), 110.6 (C(11%)), 110.6 (C(7)),
111.4 (C(3)), 118.7 (C(13%)), 119.1 (C(4)), 119.2 (C(5)),
121.8 (C(6)), 125.5 (Cpara), 127.5 (C(8%)), 128.2 (Cortho),
128.3 (Cmeta), 129.0 (C(3a)), 131.2 (C(14%)), 132.6(5)
(C(2)), 135.5(5) (Cipso), 141.9 (C(7a)), 150.8 (C(9%)),
154.9 (C(12%). MS; m/z: 493 [100, M+], 416 [12, M−
dimethoxypodocarpa
-
8,11,13
-
triene))carbene]-
chromium (17) had been produced. The solvent was
removed using an oil pump connected via a cold trap to
the flask and dibutyl ether (20 ml) was added to the
yellow–orange residue under nitrogen. The mixture was
heated to 85°C for 1.5 h under nitrogen then the
product was diluted with water and stirred overnight at
r.t. The product was extracted with Et2O, washed with
water and dried. PLC (hexanes–Et2O, 2:1) followed by
PTLC of individual fractions (hexanes–Et2O, 2:1) gave
(i) butyl 2-[13%-(12%,19%-dimethoxypodocarpa-8%,11%,13%-
triene)]-a-(phenyl)-1H-indole-3-acetate (31) (47 mg,
7.5%) as a colourless glass. Found: M+ , 593.3501.
’
Calc. for C39H47NO4: 593.3505. IR (cm−1): wmax 3401
1
(NH), 1729 (CꢂO). H-NMR: l 0.81(7) (t, J=7.4 Hz,
CH3CH2), 0.82(2) (t, J=7.4 Hz, CH3CH2), 1.04 (m,
H(3%ax)), 1.04(3) (s, H(18%)), 1.06 (s, H(18%)), 1.21–1.28
(m, CH3CH2), 1.23 (s, H(20%)), 1.26 (s, H(20%)), 1.43 (dd,
J=12.3, 1.6 Hz, H(5%)), 1.46 (dd, J=12.3, 1.7 Hz,
H(5%)), 1.50–1.58 (m, H(1%ax), CH3CH2CH2), 1.61–1.77
(m, H(2%ax), H(2%eq), H(6%ax)), 1.89 (bd, J=13.3 Hz,
H(3%eq)), 1.99 (bdd, J=12.9, 6.5 Hz, H(6%eq)), 2.31 (bd,
J=12.4 Hz, H(1%eq)), 2.69–2.85 (m, H(7%ax), H(7%eq)),
3.25 (d, J=9.1 Hz, H(19%)), 3.26 (d, J=9.1 Hz,
H(19%)), 3.34(0) (s, 19%-OMe), 3.34(5) (s, 19%-OMe), 3.54
(d, J=9.0 Hz, H(19%)), 3.71 (s, 12%-OMe), 3.72 (s,
12%-OMe), 4.10(5) (t, J=6.7 Hz, PrCH2O), 4.11(1) (t,
J=6.7 Hz, PrCH2O), 5.33(0) (s, CHPh), 5.33(5) (s,
CHPh), 6.87(0) (s, H(11%)), 6.87(4) (s, H(11%)), 6.99 (td,
J=7.5, 1.1 Hz, H(5)), 7.12 (s, H(14%)), 7.13 (s, H(14%)),
7.14 (td, J=7.7, 1.1 Hz, Hpara), 7.16–7.22 (m, H(6)),
7.23–7.26 (m, Hortho, Hmeta), 7.35 (bdd, J=8.3, 0.7 Hz,
H(7)), 7.53 (bdd, J=7.5, 0.8 Hz, H(4)), 7.54 (bdd,
J=7.5, 0.8 Hz, H(4)), 8.52 (s, NH), 8.54 (s, NH).
13C-NMR: l 13.6 (CH3CH2), 19.0 (CH3CH2), 19.1(5)
(C(2%)), 19.2 (C(6%)), 25.5 (C(20%)), 27.6 (C(18%)), 30.0
(C(7%)), 30.6 (CH3CH2CH2), 35.9 (C(3%)), 38.1 (C(10%)),
38.1(5) (C(4%)), 39.0 (C(1%)), 48.9 (CHPh), 51.2(4)
(C(5%)), 51.2(8) (C(5%)), 55.7 (12%-OMe), 59.4 (19%-OMe),
64.8 (PrCH2OCO), 75.8(6) (C(19%)), 75.9(1) (C(19%)),
107.8 (C(11%)), 109.6(8) (C(3)), 109.7(4) (C(3)), 110.6
’
Ph ].
3.20. Synthesis and thermolysis of pentacarbonyl[(2-
( ferrocenylethynyl)phenylamino)(13-(12,19-dimethoxy-
podocarpa-8,11,13-triene))carbene]chromium (18)
A solution of acetyl bromide in CH2Cl2 (0.71 ml,
0.152 g of CH3COBr per millilitre, 0.88 mmol) was
added to a solution of benzyltriethylammonium acylate
12 (0.573 g, 0.872 mmol) in CH2Cl2 (12 ml) cooled to
−30°C in a foil-covered flask under nitrogen. The
solution was stirred at −30°C for 1 h then cooled
to −78°C. A solution of 2-(ethynylferrocene)aniline
(8) (0.274 g, 0.910 mmol) and Et3N (134 ml, 0.961
mmol) in CH2Cl2 (10 ml) was added and the tempera-
ture was held at −78°C before warming to r.t.
TLC (hexanes–Et2O, 1:1) showed that pentacar-
bonyl[(2 - (ferrocenylethynyl)phenylamino)(13 - (12,19 -
dimethoxypodo - carpa - 8,11,13 - triene))carbene]-
chromium (18) had been produced. The solvent was
removed using an oil pump connected via a cold trap to
the flask, and dibutyl ether (20 ml) was then added to
the yellow–orange residue. The mixture was heated to
85°C for 2 h, cooled and filtered through Celite. Radial
chromatography (hexanes–Et2O, 1:1) followed by PLC

P.D. Woodgate, H.S. Sutherland / Journal of Organometallic Chemistry 629 (2001) 131–144
143
155.2(5) (C(12%)), 172.9 (CꢂO), 173.0 (CꢂO). MS; m/z:
(hexanes–Et2O, 1:1) gave an inseparable mixture of
butyl 2-[13%-(12%,19%-dimethoxypodocarpa-8%,11%,13%-
701 [100, M+ (32)], 601 [100, M (33)].
+
’
’
triene)]-a-(ferrocenyl)-1H-indole-3-acetate (33) (97.8
mg, 16%) and 2-[13%-(12%,19%-dimethoxypodocarpa-
8%,11%,13%-triene)]-a-(2-ferrocenylmethyl)-1H-indole (32)
3.21. Synthesis and thermolysis of pentacarbonyl-
[(2-(pyridylethynyl)phenylamino)(13-(12,19-dimethoxy-
podocarpa-8,11,13-triene))carbene]chromium (19)
(41.9 mg, 8%). Found: M+ , 701.3232. Calc. for
’
C43H51FeNO4: 701.3299 (33). Found: M+ , 601.2682.
’
Calc. for C38H43FeNO2: 601.2643 (32). IR (cm−1): wmax
A solution of acetyl bromide in CH2Cl2 (0.51 ml,
0.151 g of CH3COBr per millilitre, 0.63 mmol) was
added to a solution of benzyltriethylammonium acylate
12 (0.407 g, 0.619 mmol) in CH2Cl2 (10 ml) cooled to
−30°C in a foil-covered flask under nitrogen. The
solution was stirred at −30°C for 1 h then cooled to
−78°C. A solution of 2-(2%-pyridinylethynyl)aniline (9)
(0.127 g, 0.654 mmol) and Et3N (100 ml, 0.717 mmol) in
CH2Cl2 (10 ml) was added and the temperature was
held at −78°C for 2 h before warming the mixture to
1
3401 (NH), 1736 (CꢂO), 1107 (CꢁOꢁC). H-NMR: l
0.83–0.90 (m, CH3CH2), 1.03–1.06 (m, H(3%ax)), 1.05
(s, H(18%)), 1.08 (s, H(18%)), 1.21–1.28 (m, CH3CH2),
1.23 (s, H(20%)), 1.25 (s, H(20%)), 1.26 (s, H(20%)), 1.38
(bt, J=13.0 Hz, H(5%)), 1.47 (b, H(1%ax)), 1.50–1.75 (m,
CH3CH2CH2, H(2%ax), H(2%eq), H(6%ax)), 1.92 (bd, J=
12.8 Hz, H(3%eq)), 1.93 (b, H(6%eq)), 2.25–2.33 (m,
H(1%eq)), 2.63–2.66 (m, H(7%ax), H(7%eq)), 3.24 (d, J=
9.0 Hz, H(19%)), 3.26 (d, J=9.0 Hz, H(19%)), 3.34 (s,
19%-OMe), 3.36 (s, 19%-OMe), 3.54 (d, J=9.0 Hz,
H(19%)), 3.56 (d, J=9.0 Hz, H(19%)), 3.68 (s, 12%-OMe),
3.69 (s, 12%-OMe), 3.70 (s, 12%-OMe), 3.71 (s, 12%-OMe),
3.75–3.81 (m, CH2CH2O), 4.09 (three lines, J=1.4 Hz,
H(2¦)), 4.18 (s, Cp), 4.25 (m, H(2¦)), 4.29 (m, H(1¦)),
4.36 (bs, CH2Fc), 4.58 (three lines, J=1.1 Hz, H(1¦)),
4.60 (three lines, J=1.1 Hz, H(1¦)), 5.94 (s, COCHFc),
5.95 (s, COCHFc), 6.67 (s, H(11%)), 6.70 (s, H(11%)),
6.71 (dd, J=7.9, 0.8 Hz, H(5)), 6.91–7.11 (m, H(5),
H(6)), 7.15 (d, J=8.3 Hz, H(6)), 7.23 (s, H(14%)), 7.25
(s, H(14%)), 7.31 (d, J=8.5 Hz, H(7)), 7.38 (d, J=8.3
Hz, H(7)), 7.87 (d, J=8.2 Hz, H(4)), 7.95 (d, J=8.2
Hz, H(4)), 7.80–8.00 (b, NH). 13C-NMR: l 13.7
(CH3CH2), 14.1 (CH3CH2), 19.1 (CH3CH2), 19.3
(C(2%)), 19.5 (C(6%)), 25.6 (C(20%)), 25.6(5) (C(20%)), 27.7
(C(18%)), 29.9 (C(7%)), 30.0(9) (C(7%)), 30.1 (CH2Fc), 30.2
(CH2Fc), 30.6 (CH3CH2CH2), 35.5 (C(3%)), 35.9 (C(3%)),
38.0(5) (C(10%)), 38.1 (C(4%)), 38.2 (C(4%)), 39.0 (C(1%)),
39.1 (C(1%)), 51.2 (C(5%)), 51.3 (CHFc), 55.1 (12%-OMe),
55.2 (12%-OMe), 55.4 (12%-OMe), 55.5 (12%-OMe), 59.4
(19%-OMe), 64.6 (CO2CH2), 66.8 (C5H4Fe), 66.9
(C5H4Fe), 67.0 (C5H4Fe), 67.2 (C5H4Fe), 67.3
(C5H4Fe), 67.4 (C5H4Fe), 67.5 (C5H4Fe), 68.1 (Cp),
68.2 (C5H4Fe), 68.3 (C5H4Fe), 68.5 (Cp), 68.8
(C5H4Fe), 68.9 (C5H4Fe), 69.3 (C5H4Fe), 69.4
(C5H4Fe), 69.5 (C5H4Fe), 69.9 (C5H4Fe), 75.6 (C(19%)),
75.8(5) (C(19%)), 75.9 (C(19%)), 106.5 (C(11%)), 106.7
(C(11%)), 106.9 (C(11%)), 107.0 (C(11%)), 107.3 (C(3)),
107.5 (C(3)), 110.2 (C(7)), 110.4 (C(7)), 110.8 (C(7)),
110.0 (C(7)), 117.7 (C(13%)), 117.9 (C(13%)), 118.0
(C(13%)), 118.6 (C(4)), 118.9 (C(4)), 119.0 (C(4)), 120.9
(C(5)), 121.0 (C(5)), 121.6 (C(6)), 121.7 (C(6)), 126.8
(C(8%)), 127.1 (C(8%)), 127.3 (C(8%)), 127.4 (C(8%)), 128.7
(C(3a)), 128.8 (C(3a)), 129.0 (C(3a)), 129.7 (C(3a)),
131.7 (C(14%)), 131.8 (C(14%)), 133.1 (C(2)), 133.1(7)
(C(2)), 133.2 (C(2)), 133.3 (C(2)), 135.6 (C(7a)), 135.7
(C(7a)), 151.1 (C(9%)), 151.3 (C(9%)), 151.6 (C(9%)),
155.0(9) (C(12%)), 155.1(4) (C(12%)), 155.2 (C(12%)),
r.t.
TLC
showed
that
pentacarbonyl[(2-(2%-
pyridylethynyl)phenylamino)(13 - 912,19 - dimethoxy-
podocarpa-8,11,13-triene)) carbene]chromium (19) was
present, but only as a minor component. The solvent
was removed using an oil pump connected via a cold
trap to the flask and dibutyl ether (15 ml) was added to
the yellow–brown residue under nitrogen. The mixture
was heated to 85°C for 1 h then the product was
extracted with Et2O and the extract was washed with
water and dried. Flash chromatography gave a pale
yellow oil which was purified by PLC (hexanes–Et2O,
1:1, three elutions) followed by analytical TLC (hex-
anes–Et2O, 1:1, 5 elutions) to give (i) an inseparable
mixture (19.7 mg) of butyl 2-[13%-(12%,19%-dimethoxy-
podocarpa-8%,11%,13%-triene)]-a-(2-pyridyl)-1H-indole-3-
acetate (35) (3%) and (ii) 2-[13%-(12%,19%-dimethoxypodo-
carpa-8%,11%,13%-triene)]-a-(2-pyridylmethyl)-1H-indole
(34) (3%). Found: M+
,
594.3460. Calc. for
’
C38H46N2O4: 594.3458 (35). Found: M+ , 494.2938.
’
Calc. for C33H38N2O2: 494.2933 (34). IR (cm−1): wmax
3393 (NH), 1731 (CꢂO). H-NMR: l 0.81 (t, J=7.4
1
Hz, CH2CH3), 1.02 (m, H(3%ax)), 1.03 (s, H(18%)),
1.04(6) (s, H(18%)), 1.05(5) (s, H(18%)), 1.23 (s, H(20%)),
1.25 (s, H(20%)), 1.42 (six lines, H(5%)), 1.47 (ddd, J=
12.6, 12.6, 3.9 Hz, H(1%ax)), 1.55 (p, J=CH3CH2CH2),
1.61–1.80 (m, H(2%ax), H(2%eq), H(6%ax)), 1.89 (bd, J=
13.6 Hz, H(3%eq)), 1.98 (bdd, J=13.4, 6.8 Hz, H(6%eq)),
2.30 (bd, J=12.5 Hz, H(1%eq)), 2.64–2.88 (m, H(7%ax),
H(7%eq)), 3.24 (d, J=9.1 Hz, H(19%)), 3.25 (d, J=9.1
Hz, H(19%)), 3.33(6) (s, 19%-OMe), 3.34(3) (s, 19%-OMe),
3.34(5) (s, 19%-OMe), 3.54 (d, J=9.1 Hz, H(19%)), 3.55
(d, J=9.1 Hz, H(19%)), 3.67(4) (s, 12%-OMe), 3.67(9) (s,
12%-OMe), 3.76 (s, 12%-OMe), 4.14 (t, J=6.7 Hz,
CH2CO2Bu), 4.41 (s, CH2Py), 5.49 (s, CHCO2Bu), 5.50
(s, CHCO2Bu), 6.86 (s, H(11%)), 6.87 (s, H(11%)), 7.00–
7.19 (m, H(14%), H(5), H(6), H(5¦)), 7.35 (bd, J=7.9
Hz, H(7)), 7.39 (dd, J=8.0, 1.5 Hz, H(3¦)), 7.44–7.50
(m, H(4¦)), 7.58 (bd, J=7.9 Hz, H(4)), 8.57–8.60 (m,
NH, H(6¦)), 8.76 (s, NH). 13C-NMR: l 13.6 (CH3CH2),
19.0 (C(2%)), 19.1 (CH2CH3), 19.2 (C(2%)), 25.5 (C(20%)),

144
P.D. Woodgate, H.S. Sutherland / Journal of Organometallic Chemistry 629 (2001) 131–144
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(1992) 8088.
27.6 (C(18%)), 30.0 (C(7%)), 30.5 (CH3CH2CH2), 34.0
(CH2Py), 35.9 (C(3%)), 38.0(4) (C(10%)), 38.0(9) (C(4%)),
38.1(4) (C(4%)), 39.0 (C(1%)), 51.2 (C(5%)), 51.8
(BuO2CCHPy), 55.5(5) (12%-OMe), 55.5(7) (12%-OMe),
55.7 (12%-OMe), 59.4 (19%-OMe), 64.8 (COOCH2), 75.8
(C(19%)), 107.5(8) (C(11%)), 107.6(3) (C(11%)), 108.4
(C(3)), 108.5 (C(3)), 110.0 (C(7)), 110.7 (C(7)), 117.9(5)
(C(13%)), 118.4 (C(13%)), 119.1 (C(4)), 119.2(5) (C(4)),
119.5 (C(5¦)), 120.8 (C(5¦)), 121.3 (C(5)), 121.3(5)
(C(5)), 121.5 (C(6)), 121.8 (C(6)), 122.5 (C(6)), 123.0
(C(3¦)), 127.2 (C(8%)), 127.5(5), C(8%)) (127.6, C(3a)
(128.7, C(3a)), 131.2(5) (C(14%)), 132.0 (C(14%)), 132.1
(C(14%)), 133.1 (C(2)), 134.3(8) (C(2)), 134.4(3) (C(2)),
135.6 (C(7a)), 135.8 (C(7a)), 136.2(5) (C(4¦)), 136.4(5)
(C(4¦)), 148.7(7) (C(6¦)), 148.8(1) (C(6¦)), 151.0 (C(9%)),
151.6 (C(9%)), 154.9 (C(12%)), 155.2 (C(12%)), 159.4
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’
[100, M+ (34)].
’
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