Reactions of complex ligands. Part 94. Chromium-templated angular versus linear benzannulation of dibenzofuran and haptotropic metal migration in tetracyclic fused arenes

Article abstract of DOI:10.1016/S0022-328X(01)01299-2

The chromium-templated [3+2+1]-benzannulation of dibenzofuryl(methoxy)carbene complex 1 with alkynes leads to hydroquinoid benzonaphthofurans. A competition of angular versus linear annulation affords angular-fused (η⁶-1,2,3,4,4a,11c)-benzo[b]n

Full text of DOI:10.1016/S0022-328X(01)01299-2

Journal of Organometallic Chemistry 641 (2002) 185–194
www.elsevier.com/locate/jorganchem
Reactions of complex ligands Part 94.ꢀ
Chromium-templated angular versus linear benzannulation of
dibenzofuran and haptotropic metal migration in tetracyclic fused
arenes
Holger Christian Jahr a, Martin Nieger b, Karl Heinz Do¨tz a,*
a Kekule´-Institut fu¨r Organische Chemie und Biochemie der Rheinischen Friedrich-Wilhelms-Uni6ersita¨t Bonn, Gerhard-Domagk-Straße 1,
53121 Bonn, Germany
b Institut fu¨r Anorganische Chemie der Rheinischen Friedrich-Wilhelms-Uni6ersita¨t Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
Received 16 August 2001; accepted 24 August 2001
Abstract
The chromium-templated [3+2+1]-benzannulation of dibenzofuryl(methoxy)carbene complex 1 with alkynes leads to hy-
droquinoid benzonaphthofurans. A competition of angular versus linear annulation affords angular-fused (h6-1,2,3,4,4a,11c)-ben-
zo[b]naphtho[1,2-d]furan tricarbonyl chromium complexes 2–6 along with considerable amounts of uncoordinated
benzo[b]naphtho[2,3-d]furans as linear annulation products 7–9. As demonstrated for 2 and 6 the Cr(CO)3 complexes undergo a
thermally induced haptotropic metal migration along the tetracyclic heteroaromatic p-system to give (h6-7a,8,9,10,11,11a)-benzo-
naphthofuran complexes 10 and 11 in which the chromium fragment is coordinated to the terminal unsubstituted benzoid ring.
The molecular structures of both the kinetic annulation products and the thermodynamic rearrangement products were
established by NMR spectroscopy and single crystal X-ray analysis. © 2002 Published by Elsevier Science B.V.
Keywords: Chromium; Carbene complexes; Benzannulation; Benzonaphthofurans; Haptotropic metal migration
ligands an angular annulation pattern has been gener-
ally observed [3], even in cases where an ortho-substitu-
tion has been applied to force the annulation to linear.
So far, there is only a single early report of a linear
benzannulation [4]; a more recent study confirmed the
preference of angular over linear benzannulation [5]
which, however, also may depend on the ortho-substitu-
tion pattern [6].
Organometallic fragments coordinated to fused
arenes are capable of haptotropic migrations along the
p-system. This process has been most extensively studied
for (naphthalene)Cr(CO)3 complexes; synthetic, kinetic
and theoretical studies suggest an intramolecular metal
shift along one face and close to the periphery of the
aromatic p-system [7].
1. Introduction
Annulation provides an established access to bi- and
oligocyclic ring systems. Whereas this approach gen-
erally keeps the balance of functionalization present in
the starting material, a metal-templated assembly of
building blocks may introduce additional functional
groups along the cyclization sequence. In this respect,
the benzannulation of arylcarbene ligands by an alkyne
and carbon monoxide occurring at a Cr(CO)3 template
has received considerable attention as a straightforward
route to densely substituted oxygenated arenes [2]. The
reaction is compatible with a series of functional groups
both in the alkyne and in the carbene ligand; when
extended from phenyl to bi- and tricyclic arylcarbene
Following our interest to homologize fused arenes
and label them by organometallic fragments, we applied
the chromium-mediated benzannulation to dibenzo-
furan; we now report on its regioselectivity and on the
haptotropic migration of the chromium template along
the tetracyclic annulation product.
ꢀ For Part 93, see Ref. [1].
* Corresponding author. Tel.: +49-228-735609; fax: +49-228-
735813.
E-mail address: doetz@uni-bonn.de (K.H. Do¨tz).
0022-328X/02/$ - see front matter © 2002 Published by Elsevier Science B.V.
PII: S0022-328X(01)01299-2

186
H.C. Jahr et al. / Journal of Organometallic Chemistry 641 (2002) 185–194
Scheme 1. Synthesis of pentacarbonyl[2-dibenzofuryl(methoxy)carbene]chromium.
2. Benzonaphthofurans via [3+2+1]-benzannulation
uncoordinated
benzo[b]naphtho[2,3-d]furans
7–9
of a chromium dibenzofurylcarbene complex
(Scheme 2) as unprecedented linear benzannulation
products. The relevant substitution pattern was first
1
Bromination of dibenzofuran according to a slightly
modified literature procedure yielded 2-bromodibenzo-
furan [8] which after low-temperature lithiation with
n-butyl lithium was applied to the Fischer carbene
complex synthesis. Addition to hexacarbonyl chromium
followed by alkylation with trimethyloxoniumte-
trafluoroborate gave the pentacarbonyl[2-dibenzofuryl(-
methoxy)carbene] complex (1) (Scheme 1). Red crystals
suitable for X-ray analysis (Fig. 1) were grown from a
toluene solution of 1 by slow evaporation of the
solvent.
[3+2+1]-Benzannulation of pentacarbonyl[2-diben-
zofuryl(methoxy)carbene]chromium (1) with various
alkynes in tert-butyl methyl ether at 50 °C and subse-
quent silylation with tert-butyldimethylsilyl chloride or
trifluoromethanesulfonic acid tert-butyldimethylsilyl es-
ter led to benzo[b]naphtho[1,2-d]furan complexes 2–6
(Scheme 2). In some cases, the silylation was not quan-
titative and less stable unprotected tricarbonyl com-
plexes 4 and 6 were isolated; obviously an increasing
steric demand of the substituent next to the phenolic
group hampers the protection procedure with the bulky
silylation reagent. Upon cooling of a toluene solution
of 2 to −30 °C, single crystals suitable for X-ray
analysis were obtained (Fig. 2). The bond lengths be-
tween chromium and the carbon atoms of the coordi-
suggested by their H-NMR data and finally confirmed
by X-ray analysis of colourless prisms obtained upon
slow evaporation of the solvent from a toluene solution
of 7 (Fig. 3). Similar to the structure of 2 alternating
bond lengths are observed within the naphthoid part of
7.
The formation of benzo[b]naphtho[2,3-d]furans 7–9
provides the first example in which an arylcarbene
ligand bearing two hydrogen atoms ortho to the ring
carbon atom connected with the carbene carbon atom
undergoes a linear benzannulation. The observation
that — in contrast to the angular annulation
product — the linear annulation is accompanied by
decomplexation is remarkable and deserves further
comment. The reason for this behaviour remains un-
clear at the moment. Loss of the chromium template
,
nated hydroquinoid ring range from 2.23 to 2.30 A.
The conformation of the Cr(CO)3-fragment is close to
eclipsed with respect to the carbon atoms C1, C3 and
C4a. Interestingly, the aromatic skeleton is screwed
towards the chromium fragment, as indicated by tor-
sion angles of up to 12° for the benzonaphthofuran
system which also reveals alternating bond lengths
within the coordinated hydroquinoid and its adjacent
ring. As suggested by a donor–acceptor distance of
Fig. 1. Molecular structure of pentacarbonyl[2-dibenzofuryl(-
,
methoxy)carbene] complex (1). Selected bond lengths (A): C2ꢀC10,
,
3.36 A an intermolecular hydrogen bonding involving a
1.496(4); C10ꢀO1, 1.329(3); Cr1ꢀC10, 2.072(3); Cr1ꢀC1a, 1.879(4);
Cr1ꢀC1b, 1.902(3); Cr1ꢀC1c, 1.911(3); Cr1ꢀC1d, 1.895(3); Cr1ꢀC1e,
1.898(3). Selected bond angles (°): O1ꢀC10ꢀC2, 104.8(2);
C2ꢀC10ꢀCr1, 127.8(2); O1ꢀC10ꢀCr1, 127.20(19); C1aꢀCr1ꢀC10,
177.19(13); C1bꢀCr1ꢀC10, 96.20(12); C1cꢀCr1ꢀC10, 89.80(12);
C1dꢀCr1ꢀC10, 91.71(11); C1eꢀCr1ꢀC10, 91.92(11). Selected torsion
angles (°): C9ꢀC9aꢀC9bꢀC1, −2.5(6); C1ꢀC2ꢀC10ꢀCr1, −23.2(4);
carbonyl oxygen and an aromatic hydrogen atom is
encountered in the solid state.
Whereas the chromium-templated benzannulation
generally occurs in an angular fashion, the dibenzo-
furylcarbene complex 1 provides a rare example which
also allows for a linear annulation. In addition to the
angular benzonaphthofuran complexes 2–6 chromato-
graphic workup of the reaction products afforded also
C3ꢀC2ꢀC10ꢀCr1,
C1cꢀCr1ꢀC10ꢀC2,
154.28(19);
−30.7(2);
C1bꢀCr1ꢀC10ꢀC2,
C1dꢀCr1ꢀC10ꢀC2,
149.9(2);
−117.7(2);
C1eꢀCr1ꢀC10ꢀC2, 63.0(2).

H.C. Jahr et al. / Journal of Organometallic Chemistry 641 (2002) 185–194
187
Scheme 2. Synthesis of benzonaphthofurans via [3+2+1]-benzannulation.
prior to the formation of the vinylketene intermediate
seems unlikely, since this species is considered to result
from a metal-mediated insertion of carbon monoxide
into the h3-vinylcarbene ligand to metal bond. The
question whether the subsequent electrocyclization to
the cyclohexadienone skeleton necessarily requires the
assistance of the tricarbonyl chromium template is open
to speculation. The cyclization of uncoordinated
vinylketenes to naphthols has been reported to occur
also in the absence of a transition metal [9] under mild
conditions comparable to those applied in the
The metal migration, which also occurs in non-coordi-
nating solvents can easily be monitored by IR spec-
troscopy based on the hypsochromic shift of the
A-band in the rearranged products. Their molecular
structure bearing the chromium coordinated to the
terminal benzoid ring was elucidated from their 1H-
NMR spectra and was finally established by X-ray
analysis of complex 10 (Fig. 4). Suitable crystals for the
structure determination were obtained by evaporation
of the solvent from a toluene solution. The distances
between chromium and the carbon atoms of the coordi-
,
nated ring are between 2.20 and 2.29 A. The carbonyl
chromium-assisted
benzannulation
of
aryl(-
ligands are nearly eclipsed with the carbon atoms C7a,
C9 and C11. Torsion angles along the aromatic skele-
ton are comparable to those found for isomeric com-
methoxy)carbene ligands such as in 1 [10]. This result
may encourage to underestimate the influence of preori-
entation for the electrocyclization provided by the
metal template. So far, there is neither evidence for the
appealing idea that the annulation generally occurs in
the coordination sphere of the metal and the reduced
aromaticity of the terminal ring in the linear annulation
product is responsable for the decomplexation, nor for
the alternative that the competitive benzannulation sim-
ply reflects the kinetic stability of the vinylketene com-
plex intermediate. A DFT study is underway to shed
light on this issue.
3. Haptotropic rearrangement of chromium
benzonaphthofuran complexes
The tricarbonyl complexes 2–6 represent the kinetic
benzannulation products. Previous studies on naphtho-
hydroquinoid complexes have demonstrated that under
thermodynamic control the metal fragment migrates to
the less oxygenated ring along the same arene face [3,7].
We were interested in whether the haptotropic metal
migration is compatible with heterocyclic spacers and
more extended fused arenes. In this context we studied
the thermal behaviour of benzo[b]naphtho[1,2-d]furan
complexes 2 and 6. Upon warming in di-n-butyl ether
to 90 °C they underwent a haptotropic rearrangement
leading to isomeric complexes 10 and 11 (Scheme 3).
Fig. 2. Molecular structure of (h6-1,2,3,4,4a,11c)-benzonaphthofuran
,
complex (2). Selected bond lengths (A): C1ꢀC2, 1.408(4); C2ꢀC3,
1.443(4); C3ꢀC4, 1.391(4); C4ꢀC4a, 1.430(4); C4aꢀC5, 1.438(4);
C5ꢀC6, 1.355(4); C6ꢀC6a, 1.405(4); C6aꢀC11b, 1.384(4); C11bꢀC11c,
1.444(4); C11cꢀC1, 1.442(4); C4aꢀC11c, 1.441(4); Cr1ꢀZAr, 1.770(1);
Cr1ꢀC1, 2.304(3); Cr1ꢀC2, 2.275(3); Cr1ꢀC3, 2.230(3); Cr1ꢀC4,
2.254(3); Cr1ꢀC4a, 2.298(3); Cr1ꢀC11c, 2.267(3); Cr1ꢀC1a, 1.830(4);
Cr1ꢀC1b, 1.826(4); Cr1ꢀC1c, 1.830(3). Selected torsion angles (°):
C11ꢀC11aꢀC11bꢀC11c, −5.8(6); C11aꢀC11bꢀC11cꢀC1, −12.2(6);
C6aꢀC11bꢀC11cꢀC1, 169.6(3).

188
H.C. Jahr et al. / Journal of Organometallic Chemistry 641 (2002) 185–194
Fig. 4. Molecular structure of (h6-7a,8,9,10,11,11a)-benzonaphtho-
,
furan complex 10. Selected bond lengths (A): C1ꢀC2, 1.383(3);
C2ꢀC3, 1.427(3); C3ꢀC4, 1.382(3); C4ꢀC4a, 1.421(3); C4aꢀC5,
1.428(3); C5ꢀC6, 1.358(3); C6ꢀC6a, 1.390(3); C6aꢀC11b, 1.381(3);
C11bꢀC11c, 1.441(2); C11cꢀC1, 1.415(3); C4aꢀC11c, 1.426(3);
Cr1ꢀZAr, 1.728(1); Cr1ꢀC7a, 2.2508(19); Cr1ꢀC8, 2.237(2); Cr1ꢀC9,
2.201(2); Cr1ꢀC10, 2.200(2); Cr1ꢀC11, 2.1960(18); Cr1ꢀC11a,
2.2871(18); Cr1ꢀC1a, 1.854(2); Cr1ꢀC1b, 1.831(2); Cr1ꢀC1c, 1.842(2).
Selected torsion angles (°): C11ꢀC11aꢀC11bꢀC11c, 0.5(4);
C11aꢀC11bꢀC11cꢀC1, 11.3(3); C6aꢀC11bꢀC11cꢀC1, −174.72(17).
Fig. 3. Molecular structure of the linear benzannulation product 7.
,
Selected bond lengths (A): C5aꢀC6, 1.358(3); C6ꢀC6a, 1.420(3);
C6aꢀC7, 1.424(3); C7ꢀC8, 1.378(3); C8ꢀC9, 1.440(3); C9ꢀC10,
1.362(3); C10ꢀC10a, 1.427(3); C10aꢀC11, 1.414(3); C11ꢀC11a,
1.379(3); C11aꢀC5a, 1.409(3); C6aꢀC10a, 1.433(3). Selected torsion
angles (°): C11ꢀC11aꢀC11bꢀC1, −3.0(4); C10aꢀC11ꢀC11aꢀC11b,
−176.0(2); C10aꢀC11ꢀC11aꢀC5a, 1.1(3).
plex 2; however, in contrast to 2, the benzona-
phthofuran ligand is screwed away from the chromium
fragment. The solid state structure reveals five different
hydrogen bonds three of which involve carbonyl oxy-
gen atoms; donor–acceptor distances range from 3.24
ring undergo an extended haptotropic metal migration
along which the metal is shifted to the opposite termi-
nal benzene ring. These results demonstrate that this
process, which has been extensively studied in the past
for naphthalenes, can be also applied to larger fused
p-systems and even tolerates heteroarene spacers.
,
to 3.69 A.
4. Conclusions
5. Experimental
Benzannulation of chromium carbene complexes
bearing polycyclic aromatic substituents by alkynes
may lead to both angular and linear annulation prod-
ucts. Linear annulation is even compatible with an
arylcarbene substitution pattern bearing two ortho-hy-
drogen atoms as shown for the reaction of dibenzo-
furylcarbene complex 1. The kinetic benzo[b]naphtho-
[1,2-d]furan benzannulation products bearing the
chromium fragment coordinated to the hydroquinoid
5.1. General reaction conditions
All reactions were carried out under Ar atmosphere.
Solvents used for reactions and chromatography were
dried by distillation from lithium aluminium hydride
(Et2O, petroleum ether, heptane), CaH2 (tert-butyl
methyl ether, di-n-butyl ether, CH2Cl2) or from sodium
(toluene). Et3N was dried by distillation from potas-
Scheme 3. Haptotropic rearrangement of the benzonaphthofuran complexes.

H.C. Jahr et al. / Journal of Organometallic Chemistry 641 (2002) 185–194
189
sium hydroxide, 2,6-lutidine by distillation from CaH2.
Chromatography was performed with silica gel (Merck,
type 60, 0.063–0.2 mm and Machery Nagel, type 60,
0.015–0.025 mm), which was degassed at high vacuum
prior to use.
with a Nonius KappaCCD at 123 K. The molecular
structures have been solved by direct methods (1 and 7)
or Patterson methods (2 and 10) (SHELXS-97) [11]. The
non-hydrogen atoms were refined anisotropically on F2
(SHELXL-97) [12]; hydrogen atoms were refined using a
riding model. Details are presented in Table 1.
5.2. Instrumentation
5.4. Reagents
IR: Nicolet Magna 550 FT-IR. NMR: Bruker DRX
500, AM 400 and AM 250. MS (FAB, EI): Kratos
Instruments Concept 1H (mNBA matrix) and MS 50
(70 eV). Elemental analysis: Elementar Analysensys-
teme Vario EL. HPLC: Knauer injection valve A0258,
two pumps type 64, UV detector type K 2600, column
Knauer Eurospher 100 RP C-18 (250×16 mm), Eu-
rochrom 2000 for Windows.
2-Bromodibenzofuran was prepared according to a
slightly modified literature procedure [8].
5.5. Synthesis of pentacarbonyl[2-dibenzofuryl-
(methoxy)carbene]chromium (1)
To a solution of 5.9 g (23.9 mmol) of 2-bromodiben-
zofuran in 100 ml tert-butyl methyl ether 9.6 ml (24
mmol) of 2.5 M n-butyl lithium solution was added
dropwise at −70 °C. Stirring for 2 h and subsequent
warming led to a yellow solution which was transferred
into a suspension of 4.8 g (21.8 mmol) hexacarbonyl
chromium in 100 ml tert-butyl methyl ether, cooled to
−60 °C. After stirring for 3 h the reaction mixture was
allowed to warm to room temperature (r.t.). Trimethyl-
5.3. X-ray crystallographic studies of 1, 2, 7 and 10
Red crystals were obtained by cooling a toluene
solution of complex 2 to −30 °C; upon slow evapora-
tion of the solvent from a toluene solution, 1 gave red
crystals, 7 provided colourless prisms and 10 afforded
light red crystals. Crystallographic data were collected
Table 1
Crystal data and structure refinement parameters for 1, 2, 7 and 10
1
2
7
10
Empirical formula
Formula weight
Temperature (K)
C19H10CrO7
402.27
123(2)
C30H34CrO6Si·1/2 toluene
616.73
123(2)
C
434.63
123(2)
27H34O3Si
C30H34CrO6Si
570.66
123(2)
,
Wavelength (A)
0.71073
Triclinic
0.71073
Triclinic
0.71073
Triclinic
0.71073
Monoclinic
C2/c (no. 15)
Crystal system
Space group
(
(
(
P1 (no. 2)
P1 (no. 2)
P1 (no. 2)
Unit cell dimensions
,
a (A)
7.5624(4)
8.9423(4)
13.2149(7)
74.760(2)
81.624(2)
84.022(3)
851.00(7)
2
8.3424(5)
10.5552(6)
17.9899(10)
79.520(3)
82.589(3)
88.207(2)
1544.63(15)
2
9.9382(4)
10.8886(3)
12.0322(4)
109.113(2)
91.960(2)
102.655(2)
1192.43(7)
2
18.0990(3)
11.3470(2)
28.4012(5)
90
98.948(1)
90
5761.75(17)
8
1.316
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
V (A )
3
,
Z
Dcalc (g cm−3
)
1.570
0.713
408
1.326
0.452
650
1.211
0.124
468
v (mm−1
F(000)
)
0.479
2400
Crystal size (mm)
Diffractometer
Radiation
0.15×0.10×0.05
Nonius KappaCCD
Mo–Ka
50.00
0.20×0.15×0.05
Nonius KappaCCD
Mo–Ka
0.20×0.15×0.10
Nonius KappaCCD
Mo–Ka
0.45×0.40×0.35
Nonius KappaCCD
Mo–Ka
50.00
Max 2q (°)
50.70
50.64
Index ranges
−75h58,
−105k510,
−155l515
6793
−95h510,
−125k512,
−215l520
11 966
−115h511,
−135k512,
−125l514
9496
−215h516,
−105k513,
−335l528
16 565
Total reflections
Unique reflections
Parameters/restraints
R for I\2|(I)
2883
244/0
0.0387
0.0646
5250
360/14
0.0448
0.1127
4205
280/0
0.0440
0.1086
5034
343/0
0.0317
0.0914
wR2 for all data
Goodness-of-fit on F2
0.892
0.963
0.926
1.052

190
H.C. Jahr et al. / Journal of Organometallic Chemistry 641 (2002) 185–194
oxoniumtetrafluoroborate (3.25 g, 22.0 mmol) was
added to the brown solution at −60 °C, which was
allowed to reach r.t. while stirring overnight. The sol-
vent was removed and the residue was subjected to
column chromatography at 0 °C using petroleum
ether–CH2Cl2 2:1 as eluent.
5.6. General procedure for the benzannulation of
carbene complex 1 yielding tricarbonyl complexes 2–6
and linear benzannulation products 7–9
To a solution of 1 in tert-butyl methyl ether an
excess of alkyne was added and the solution was heated
to 50 °C. Upon completion of the reaction the mixture
Yield: 5.43 g (13.5 mmol, 62%) of a red solid. Rf=
0.61 (petroleum ether–CH2Cl2 2:1). IR (petroleum
ether, cm−1): wCO=2062 (m, A1), 1961 (sh, A1), 1952
(vs, E), 1942 (sh, E). 1H-NMR (250 MHz, CDCl3,
ppm): l=8.09 (d, 4JHH=2.0 Hz, 1H, H1), 8.00 (d,
3JHH=7.7 Hz, 1H, H9/6), 7.71 (dd, 3JHH=8.7 Hz,
was transferred into
a
suspension of tert-
butyldimethylsilylchloride in Et3N at r.t. or into a
mixture of trifluoromethanesulfonic acid tert-
butyldimethylsilyl ester and 2,6-lutidine at 0 °C, respec-
tively, and stirred at r.t. overnight. After removal of
volatile components, the products were separated by
column chromatography at 0 °C.
3
4JHH=2.0 Hz, 1H, H3), 7.59 (d, JHH=8.2 Hz, 1H,
H6/9), 7.57 (d, 3JHH=8.8 Hz, 1H, H4), 7.50 (td,
3JHH=8.4 Hz, 4JHH=1.4 Hz, 1H, H7/8), 7.39 (td,
4
3JHH=7.9 Hz, JHH=1.1 Hz, 1H, H8/7), 4.88 (s, 3H,
OCH3). 13C-NMR (62.5 MHz, CDCl3, ppm): l=346.5
(CꢁCr), 223.8 (trans-CO), 216.5 (cis-CO), 157.0, 149.1
(2ArCO), 128.0 (ArCH), 125.7 (ArCH), 124.0 (ArC),
123.9 (ArC), 123.3 (ArCH), 120.9 (ArCH), 117.5
(ArCH), 112.0 (ArCH), 111.2 (ArCH, 10ArC), 67.4
(OCH3). FABMS; m/z (%): 402 (9) [M+], 374 (20)
[M+−CO], 346 (23) [M+−2CO], 318 (13) [M+−
3CO], 307 (100) [(2 matrix+H)+], 290 (40) [M+−
4CO], 262 (25) [M+−5CO] (Table 2).
5.6.1. Tricarbonyl[(p6-1,2,3,4,4a,11c)-1-tert-butyldime-
thylsilyloxy-2,3-diethyl-4-methoxybenzo[b]naphtho-
[1,2-d]furan]chromium (2) and 7-tert-butyldimethyl-
silyloxy-8,9-diethyl-10-methoxybenzo[b]naphtho[1,2-d]-
furan (7)
Carbene complex 1: 1.00 g (2.5 mmol); 3-hexyne: 0.85
ml (7.5 mmol); tert-butyl methyl ether: 60 ml; tert-
butyldimethylsilylchloride: 3.77 g (25.0 mmol); Et3N:
3.48 ml (25.0 mmol).
5.6.1.1. Tricarbonyl[(p6-1,2,3,4,4a,11c)-1-tert-butyl-
dimethylsilyloxy-2,3-diethyl-4-methoxybenzo[b]-
naphtho[1,2-d]furan]chromium (2). Yield: 0.43
Table 2
Atomic coordinates (×104) and equivalent isotropic displacement
2
3
,
parameters (A ×10 ) for 1
g
a
(0.75 mmol, 30%) of red crystals. Rf=0.44 (petroleum
x
y
z
Ueq
ether–Et2O 10:1). IR (petroleum ether, cm−1): wCO
=
1
Cr1
C1a
O1a
C1b
O1b
C1c
O1c
C1d
O1d
C1e
O1e
C1
C2
C3
C4
C4a
O5
C5a
C6
C7
C8
C9
C9a
C9b
C10
O1
2140(1)
2441(4)
2616(3)
387(4)
−665(3)
3954(4)
5087(3)
4016(4)
5196(3)
255(4)
−916(3)
2066(3)
2202(3)
2704(3)
3091(4)
2941(4)
3328(2)
3103(4)
3420(4)
3131(4)
2563(4)
2263(4)
2543(4)
2435(3)
1907(3)
1600(2)
1416(4)
2342(1)
443(4)
2547(1)
2163(2)
1913(2)
1592(2)
1021(2)
3452(2)
3945(2)
1463(2)
818(2)
3593(2)
4171(2)
4986(2)
4062(2)
4126(2)
5045(2)
5932(2)
6918(1)
7548(2)
8601(2)
9102(2)
8587(2)
7525(2)
7004(2)
5925(2)
3016(2)
2423(1)
1309(2)
23(1)
27(1)
37(1)
28(1)
44(1)
24(1)
37(1)
25(1)
35(1)
23(1)
34(1)
21(1)
18(1)
22(1)
25(1)
23(1)
27(1)
24(1)
30(1)
33(1)
32(1)
27(1)
23(1)
20(1)
20(1)
25(1)
29(1)
1959 (vs, A1), 1894 (s, E), 1882 (s, E). H-NMR (250
3
MHz, CDCl3, ppm): l=8.69 (d, JHH=7.3 Hz, 1H,
−708(2)
2949(3)
3161(3)
1541(3)
1000(2)
3062(3)
3407(2)
1512(3)
955(2)
3402(3)
4616(3)
6068(3)
6334(3)
5095(4)
5146(2)
3650(4)
3183(4)
1645(4)
644(4)
H11), 7.86 (d, 3JHH=9.5 Hz, 1H, H5/6), 7.78 (d,
3
3JHH=9.5 Hz, 1H, H5/6), 7.62 (d, JHH=7.9 Hz, 1H,
3
4
H8), 7.49 (td, JHH=7.7 Hz, JHH=1.0 Hz, 1H, H9/
10), 7.40 (td, 3JHH=7.0 Hz, 4JHH=1.0 Hz, 1H, H10/9),
4.03 (s, 3H, OCH3), 2.99 (dq, JHH=13.7 Hz, JHH
2
3
=
2
3
7.4 Hz, 1H, CH2), 2.75 (dq, JHH=13.7 Hz, JHH=7.4
Hz, 1H, CH2), 2.70 (dq, 2JHH=14.2 Hz, 3JHH=7.4 Hz,
1H, CH2), 2.34 (dq, 2JHH=14.2 Hz, 3JHH=7.4 Hz, 1H,
3
CH2), 1.50 (t, JHH=7.4 Hz, 3H, CH2CH3
6
), 1.29 (t,
3JHH=7.4 Hz, 3H, CH2CH3
6 ), 1.12 (s, 9H, C(CH3),
−0.21 (s, 3H, SiCH3), −0.60 (s, 3H, SiCH3). 13C-
NMR (62.5 MHz, CDCl3, ppm): l=233.9 (Cr(CO)3),
155.6, 152.5 (C6a, C7a), 129.6 (ArC), 127.5, 126.9
(ArCH), 124.5, 122.7, 122.0, 119.4, 111.3 (ArCH), 111.2
(ArCH), 104.6 (ArCCr), 104.0 (ArCCr, 14ArC), 67.2
(OCH3), 26.5 (C(C
6
H3)3), 21.6, 19.7 (2CH2), 18.8, 18.7
H3), −2.1, −4.9
1167(4)
2684(4)
3642(3)
4398(3)
5828(2)
6201(3)
(C(CH3)3), CH2CH3), 14.7 (CH2C
6
6
6
(Si(CH3)2). EIMS; m/z (%): 570 (15) [M+], 514 (5)
[M+−2CO], 486 (100) [M+−3CO], 434 (39) [M+−
Cr(CO)3], 377 (12) [M+−Cr(CO)3−C(CH3)3], 348
(17) [M+−Cr(CO)3−C(CH3)3−C2H5]. HRMS: Calc.
for C30H34O6SiCr: 570.1529. Found: 570.1527 (Table
3).
C11
a Ueq is defined as one-third of the trace of the orthogonalized Uij
tensor.

H.C. Jahr et al. / Journal of Organometallic Chemistry 641 (2002) 185–194
191
3
Table 3
2H, CH2
6
CH3), 1.33 (t, JHH=7.4 Hz, 3H, CH2CH3
6
),
Atomic coordinates (×104) and equivalent isotropic displacement
1.22 (t, 3JHH=7.4 Hz, 3H, CH2CH3
6 ), 1.19 (s, 9H,
2
3
,
parameters (A ×10 ) for 2
C(CH3)3), 0.29 (s, 6H, Si(CH3)2). 13C-NMR (100 MHz,
CDCl3, ppm): l=157.7, 154.4, 148.5, 144.7 (C4a, C5a,
C7, C10), 130.9, 129.6 (2ArC), 128.1 (ArCH), 127.6,
124.5, 124.3, 124.3 (4ArC), 122.7, 121.3, 113.5, 111.5,
a
x
y
z
Ueq
Cr1
C1a
O1a
C1b
O1b
C1c
O1c
C1
C2
C3
C4
C4a
C5
C6
C6a
O7
C7a
C8
C9
C10
C11
C11a
C11b
C11c
O11
Si1
C12
C13
C14
C15
C16
C17
C21
C22
C31
C32
O41
C41
C1t
C2t
C3t
C4t
C5t
C6t
C7t
7654(1)
4645(1)
5135(3)
5469(2)
6219(3)
7233(2)
5415(3)
5922(2)
2562(3)
2567(3)
3132(3)
3628(3)
3654(3)
4149(3)
4197(3)
3794(3)
3889(2)
3534(3)
3506(3)
3175(3)
2917(3)
2960(3)
3225(3)
3361(3)
3189(3)
1950(2)
356(1)
8039(1)
7573(2)
7277(1)
7598(2)
7317(1)
8834(2)
9331(1)
7873(2)
8652(2)
8879(2)
8331(2)
7536(2)
6995(2)
6237(2)
6002(2)
5245(1)
5228(2)
4567(2)
4644(2)
5366(2)
6023(2)
5960(2)
6476(2)
7288(2)
7658(1)
7631(1)
6691(2)
8347(2)
7828(2)
7186(2)
7886(3)
8576(2)
9245(2)
9499(2)
9715(2)
20(1)
24(1)
33(1)
24(1)
39(1)
25(1)
42(1)
19(1)
19(1)
20(1)
20(1)
20(1)
25(1)
26(1)
24(1)
29(1)
25(1)
33(1)
34(1)
30(1)
25(1)
23(1)
20(1)
19(1)
20(1)
26(1)
38(1)
38(1)
34(1)
44(1)
79(2)
68(2)
24(1)
37(1)
25(1)
34(1)
25(1)
30(1)
40(2) b
47(2) b
47(2) b
53(3) b
38(2) b
36(2) b
45(2) b
9675(4)
10951(3)
6934(4)
6510(3)
8018(4)
8216(3)
8262(4)
7783(4)
6256(4)
5257(4)
5741(4)
4646(4)
5069(4)
6644(4)
7227(3)
8826(4)
9864(4)
11456(4)
11981(4)
10918(4)
9290(4)
7804(4)
7327(3)
9670(2)
9888(1)
9508(4)
8336(4)
12028(4)
13268(4)
12233(5)
12403(5)
8825(4)
9981(4)
5653(4)
4669(4)
3696(2)
3398(4)
3768(7)
4355(8)
5755(8)
6569(7)
5982(7)
4582(7)
3907(9)
103.2 (5ArCH), 62.5 (OCH3), 26.2 (C(C
(2CH2CH3), 18.8 (C(CH3)3), 16.1, 15.0 (2CH2C
6
H3)3), 20.8, 20.2
H3), −
6
6
6
2.9 (Si(CH3)2). EIMS; m/z (%): 434 (100) [M+], 419
(42) [M+−CH3], 377 (7) [M+−C(CH3)3], 348 (13)
[M+−C(CH3)3−C2H5], 333 (12) [M+−C(CH3)3−
C2H5−CH3], 73 (100) [(Si(CH3)3)+]. HRMS: Calc. for
C27H34O3Si: 434.2277 Found: 434.2272 (Table 4).
5.6.2. Tricarbonyl[(p6-1,2,3,4,4a,11c)-1-tert-butyl-
dimethylsilyloxy-4-methoxy-3-n-propylbenzo[b]-
naphtho[1,2-d]furan]chromium (3) and 7-tert-butyl-
dimethylsilyloxy-10-methoxy-8-n-propylbenzo[b]-
naphtho[2,3-d]furan (8)
Carbene complex 1: 1.38 g (3.4 mmol); 1-pentyne:
2.71 ml (27.4 mmol); tert-butyl methyl ether: 10 ml;
trifluoromethanesulfonic acid tert-butyldimethylsilyl es-
ter: 3.90 ml (17.0 mmol); 2,6-lutidine: 1.98 ml (17.0
mmol).
5.6.2.1.
Tricarbonyl[(p6-1,2,3,4,4a,11c)-1-tert-butyl-
16(3)
dimethylsilyloxy-4-methoxy-3-n-propylbenzo[b]naphtho-
[1,2-d]furan]chromium (3). Yield: 0.28 g (0.50 mmol,
15%) of a red solid. Rf=0.39 (petroleum ether–CH2Cl2
2:1). IR (petroleum ether, cm−1): wCO=1961 (vs, A1),
−566(3)
−61(3)
596(4)
−1531(4)
308(5)
1920(3)
2795(3)
3115(3)
1882(3)
3993(2)
5338(3)
−459(6)
645(6)
1
1898 (s, E), 1888 (s, E). H-NMR (500 MHz, CD2Cl2,
ppm): l=8.59 (ddd, 3JHH=8.0 Hz, 4JHH=1.4 Hz,
5JHH=0.6 Hz, 1H, H11), 8.11 (d, JHH=9.4 Hz, 1H,
3
3
10054(2)
8568(1)
8576(2)
4837(3)
4344(3)
4463(3)
5075(4)
5568(3)
5449(3)
5979(4)
H5/6), 7.76 (d, JHH=9.4 Hz, 1H, H5/6), 7. 59 (ddd,
3JHH=8.2 Hz, JHH=1.1 Hz, JHH=0.6 Hz, 1H, H8),
4
5
3
4
7.52 (td, JHH=7.7 Hz, JHH=1.4 Hz, 1H, H9), 7.43
(td, JHH=7.6 Hz, JHH=1.1 Hz, 1H, H10), 5.50 (s,
1H, H3), 4.00 (s, 3H, OCH3), 2.90 (ddd, JHH=15.9
Hz, JHH=12.4 Hz, JHH=4.7 Hz, 1H, CH6 2CH2CH3),
3
4
2
1218(6)
687(6)
−417(6)
−990(5)
−2191(7)
3
3
2
3
3
2.71 (ddd, JHH=15.9 Hz, JHH=12.1 Hz, JHH=5.0
Hz, 1H, CH2CH2CH3), 2.07 (m, 1H, CH2CH2CH3),
1.85 (m, 1H, CH2CH2CH3), 1.18 (t, JHH=7.3 Hz, 3H,
CH2CH3), 1.12 (s, 9H, C(CH3)3), −0.18 (s, 3H,
6
6
3
6
a Ueq is defined as one-third of the trace of the orthogonalized Uij
tensor.
b s.o.f.=0.50.
6
SiCH3), −0.57 (s, 3H, SiCH3). 13C-NMR (125 MHz,
CD2Cl2, ppm): l=233.9 (Cr(CO)3), 155.7, 154.5
(2ArCO), 135.8 (ArC), 128.0, 126.7 (2ArCH), 125.0
(ArC), 123.8, 122.8 (2ArCH), 117.7 (ArC), 116.6, 111.2
(2ArCH), 103.0, 97.2 (ArCCr), 73.6 (ArCHCr), 56.7
5.6.1.2.
7-tert-Butyldimethylsilyloxy-8,9-diethyl-10-
methoxybenzo[b]naphtho[1,2-d]furan (7). Yield: 0.42 g
(0.97 mmol, 39%) of colourless prisms. Rf=0.73
(petroleum ether–Et2O 10:1). 1H-NMR (400 MHz,
CDCl3, ppm): l=8.59 (s, 1H, H6), 8.15 (s, 1H, H11),
8.12 (d, 3JHH=7.8 Hz, 1H, H1), 7.59 (d, 3JHH=8.2 Hz,
1H, H4), 7.50 (t, 3JHH=7.8 Hz, 1H, H3), 7.38 (t,
(OCH3), 32.7 (C
(C6 H2CH3), 19.0 (C
6
H2CH2CH3), 26.5 (C(C
(CH3)3), 14.1 (CH2CH3), −2.3, −
6 H3)3), 21.5
6
6
4.9 (Si(CH3)2). EIMS; m/z (%): 556 (5) [M+], 500 (2)
[M+−2CO], 472 (27) [M+−3CO], 420 (100) [M+−
Cr(CO)3], 363 (87) [M+−Cr(CO)3−C(CH3)3], 320
(59) [M+−Cr(CO)3−C(CH3)3−CH2CH2CH3], 305
3JHH=7.2 Hz, 1H, H2), 4.05 (s, 3H, OCH3), 2.94 (q,
3JHH=7.4 Hz, 2H, CH2
6
CH3), 2.90 (q, JHH=7.4 Hz,
(25)
[M+−Cr(CO)3−C(CH3)3−CH2CH2CH3−
3

192
H.C. Jahr et al. / Journal of Organometallic Chemistry 641 (2002) 185–194
Table 4
124.4, 123.6 (3ArC), 122.7 (ArCH), 122.1 (ArC), 121.2,
113.7, 111.4, 104.2, 102.7 (5ArCH), 55.6 (OCH3), 33.2
Atomic coordinates (×104) and equivalent isotropic displacement
2
3
,
parameters (A ×10 ) for 7
(C
(C6
6
H2CH2CH3), 26.2 (C(C
6
H3)3, 23.7 (C
6 H2CH3), 18.7
a
(CH)3)3), 14.1 (CH2C6 H3), −3.1 (Si(CH3)2). EIMS;
x
y
z
Ueq
m/z (%): 420 (100) [M+], 405 (7) [M+−CH3], 363 (22)
[M+−C(CH3)3], 320 (18) [M+−C(CH3)3−C3H7], 305
(17) [M+−C(CH3)3−C3H7−CH3]. HRMS: Calc. for
C26H32O3Si: 420.2121. Found: 420.2121.
C1
C2
C3
C4
C4a
O5
C5a
C6
C6a
C7
C8
2652(2)
2964(2)
3679(2)
4640(2)
4915(2)
4188(2)
4324(1)
3426(2)
3266(2)
2353(2)
2157(2)
1420(2)
732(2)
5808(2)
6264(2)
5820(2)
4907(2)
4461(2)
3546(1)
3390(2)
2585(2)
2579(2)
1802(2)
1900(2)
2743(2)
3443(2)
3422(2)
4207(2)
4198(2)
4886(2)
979(1)
27(1)
30(1)
29(1)
26(1)
22(1)
24(1)
20(1)
22(1)
20(1)
20(1)
21(1)
21(1)
21(1)
19(1)
21(1)
21(1)
22(1)
21(1)
20(1)
29(1)
27(1)
26(1)
37(1)
38(1)
38(1)
24(1)
35(1)
26(1)
32(1)
25(1)
35(1)
1688(2)
1406(2)
2071(2)
3024(2)
3789(1)
4627(2)
5557(2)
6384(2)
7428(2)
8362(2)
8206(2)
7159(2)
6232(2)
5207(2)
4411(2)
3344(2)
7544(1)
6673(1)
4783(2)
7247(2)
7081(2)
8535(2)
5989(3)
7024(3)
9593(2)
10884(2)
9123(2)
8616(2)
6962(2)
7740(3)
5.6.3. Tricarbonyl[(p6-1,2,3,4,4a,11c)-2-tert-butyl-1-
hydroxy-4-methoxybenzo[b]naphtho[1,2-d]furan]-
chromium (4) and 8-tert-butyl-7-tert-butyldimethyl-
silyloxy-10-methoxybenzo[b]naphtho[2,3-d]furan (9)
Carbene complex 1: 2.45 g (6.1 mmol); 3,3-dimethyl-
1-butyne: 3.71 ml (30.5 mmol); tert-butyl methyl ether:
15 ml; tert-butyldimethylsilylchloride: 9.19 g (61.0
mmol); Et3N: 8.48 ml (61.0 mmol).
C9
C10
C10a
C11
C11a
C11b
O71
Si71
C71
C72
C73
C74
C75
C76
C81
C82
C91
C92
O101
C101
847(2)
1674(2)
1844(2)
2731(2)
3225(2)
2803(1)
2168(1)
1632(2)
681(2)
3586(2)
3729(2)
3279(3)
4902(2)
1416(2)
2472(2)
−202(2)
5.6.3.1. Tricarbonyl[(p6-1,2,3,4,4a,11c)-2-tert-butyl-1-
hydroxy - 4 - methoxybenzo[b]naphtho[1,2 - d]furan]chro-
mium (4). Yield: 0.65 g (1.42 mmol, 23%) of a red solid.
Rf=0.73 (petroleum ether–Et2O 3:1). IR (CH2Cl2,
−383(1)
−302(2)
−1324(2)
−984(2)
−1403(2)
−2044(2)
−32(2)
1197(2)
1898(2)
2773(2)
1800(2)
1
cm−1): wCO=1951 (vs, A1), 1871 (s, br, E). H-NMR
3
(500 MHz, CD2Cl2, ppm): l=8.74 (d, JHH=8.1 Hz,
3
1H, H11), 8.22 (d, JHH=9.4 Hz, 1H, H5/6), 7.86 (d,
3
3JHH=9.4 Hz, 1H, H5/6), 7.72 (d, JHH=8.2 Hz, 1H,
H8), 7.55 (t, 3JHH=7.6 Hz, 1H, H9/10), 7.47 (t, 3JHH
=
7.7 Hz, 1H, H10/9), 5.63 (s, 1H, H3), 5.49 (s, 1H, OH),
3.96 (s, 3H, OCH3), 1.67 (s, 9H, C(CH3)3). 13C-NMR
(125 MHz, CD2Cl2, ppm): l=233.9 (Cr(CO)3), 127.1,
125.9, 124.5, 123.6, 117.1, 111.9 (6ArCH), 74.0
−1571(2)
140(1)
4235(1)
5376(2)
883(2)
(ArCHCr), 57.1 OCH3, 34.2 (C6 (CH3)3), 30.5 (C(C6 H3)3).
a Ueq is defined as one-third of the trace of the orthogonalized Uij
tensor.
EIMS; m/z (%): 456 (1) [M+], 400 (1) [M+−2CO], 372
(9) [M+−3CO], 320 (100) [M+−Cr(CO)3], 305 (63)
[M+−Cr(CO)3−CH3], 273 (16) [M+−Cr(CO)3−
2CH3−OH]. HRMS: Calc. for C24H20O6Cr: 456.0666.
Found: 456.0661.
CH3]. HRMS: Calc. for C29H32O6SiCr: 556.1373.
Found: 556.1375. Elemental analysis: Calc. for
C29H32O6SiCr: C, 62.57; H, 5.79. Found: C, 62.72; H,
5.99%.
5.6.3.2.
8-tert-Butyl-7-tert-butyldimethylsilyloxy-10-
methoxybenzo[b]naphtho[2,3-d]furan (9). Yield: 0.51 g
(1.16 mmol, 20%) of a white solid. Rf=0.80 (petroleum
5.6.2.2. 7-tert-Butyldimethylsilyloxy-10-methoxy-8-n-
propylbenzo[b]naphtho[2,3-d]furan (8). Yield: 0.21 g
(0.50 mmol, 15%) of a white solid. Rf=0.68 (petroleum
1
ether–CH2Cl2 6:5). H-NMR (250 MHz, CDCl3, ppm):
3
l=8.70 (s, 1H, H6), 8.14 (s, 1H, H11), 8.05 (d, JHH
=
1
3
ether–CH2Cl2 2:1). H-NMR (500 MHz, CDCl3, ppm):
7.9 Hz, 1H, H1), 7.55 (d, JHH=7.9 Hz, 1H, H4), 7.47
5
3
4
l=8.77 (d, 5JHH=0.8 Hz, 1H, H6), 8.10 (d, JHH=0.8
(td, JHH=7.8 Hz, JHH=1.3 Hz, 1H, H3), 7.34 (td,
3
4
4
Hz, 1H, H11), 8.06 (ddd, JHH=7.7 Hz, JHH=1.3 Hz,
5JHH=0.6 Hz, 1H, H1), 7.56 (ddd, 3JHH=8.2 Hz,
4JHH=0.9 Hz, 5JHH=0.6 Hz, 1H, H4), 7.47 (td,
3JHH=7.8 Hz, 4JHH=1.3 Hz, 1H, H3), 7.35 (td,
3JHH=7.4 Hz, JHH=1.1 Hz, 1H, H2), 6.81 (s, 1H,
H9), 4.05 (s, 3H, OCH3), 1.52 (s, 9H, C(CH3)3), 1.12 (s,
9H, C(CH3)3), 0.22 (s, 6H, Si(CH3)2). 13C-NMR (62.5
MHz, CDCl3, ppm): l=157.7, 154.7, 149.4, 141.7
(C4a, C5a, C7, C10), 133.0, 129.4 (2ArC), 127.8
(ArCH), 124.4, 123.7 (2ArC), 122.6 (ArCH), 122.1
(ArC), 121.2, 113.1, 111.4, 103.8, 103.5 (5ArCH), 55.5
4
3JHH=7.8 Hz, JHH=0.9 Hz, 1H, H2), 6.61 (s, 1H,
3
H9), 4.05 (s, 3H, OCH3), 2.78 (t, JHH=7.8 Hz, 2H,
3
3
CH
2H, CH2
Hz, 3H, CH2CH3
6
2CH2CH3), 1.70 (tq, JHH=7.8 Hz, JHH=7.4 Hz,
CH3), 1.17 (s, 9H, C(CH3)3), 1.00 (t, 3JHH=7.4
), 0.22 (s, 6H, Si(CH3)2). 13C-NMR
6
(OCH3), 36.1 (CC6 (CH3)3), 32.1 (CC(C6 H3)3, 26.9
6
(SiC(C6 H3)3), 19.2 (SiC6 (CH3)3), −1.3 (Si(CH3)2). EIMS;
(125 MHz, CDCl3, ppm): l=157.6, 155.1, 150.3, 141.3
m/z (%): 434 (100) [M+], 419 (18) [M+−CH3]. HRMS:
(C4a, C5a, C7, C10), 128.9 (ArC), 127.8 (ArCH), 127.0,
Calc. for C27H34O3Si: 434.2277. Found: 434.2271.

H.C. Jahr et al. / Journal of Organometallic Chemistry 641 (2002) 185–194
193
5.6.4. Tricarbonyl[(p6-1,2,3,4,4a,11c)-1-tert-butyl-
5.7. General procedure for the haptotropic
dimethylsilyloxy-4-methoxy-2,3-diphenylbenzo[b]-
naphtho[1,2-d]furan]chromium (5) and tricarbonyl-
[(p6-1,2,3,4,4a,11c)-1-hydroxy-4-methoxy-2,3-
diphenylbenzo[b]naphtho[1,2-d]furan]chromium (6)
Carbene complex 1: 1.25 g (3.1 mmol); dipheny-
lacetylene: 0.61 g (3.4 mmol); tert-butyl methyl ether:
15 ml; tert-butyldimethylsilylchloride: 4.67 g (31.0
mmol); Et3N: 3.14 ml (31.0 mmol).
rearrangement of the tricarbonylchromium complexes 2
and 6 yielding the isomeric complexes 10 and 11
A solution of the tricarbonylchromium complex in
di-n-butyl ether was heated to 90 °C. Within 4 h the
colour of the solution changed from intense red to
bright yellow. The reaction was monitored by IR spec-
troscopy; upon completion of the rearrangement the
solvent was removed and the product was purified by
column chromatography at 0 °C.
5.6.4.1. Tricarbonyl[(p6-1,2,3,4,4a,11c)-1-tert-butyldi-
methylsilyloxy-4-methoxy-2,3-diphenylbenzo[b]naphtho-
[1,2-d]furan]chromium (5). Yield: 0.03 g (0.04 mmol,
1%) of a red solid and 0.38 g of a 5 containing fraction.
Rf=0.43 (petroleum ether–CH2Cl2 2:1). IR (petroleum
ether, cm−1): wCO=1961 (vs, A1), 1902 (s, E), 1890 (s,
5.7.1. Tricarbonyl[(p6-7a,8,9,10,11,11a)-1-tert-butyl-
dimethylsilyloxy-2,3-diethyl-4-methoxybenzo[b]naphtho-
[1,2-d]furan]chromium (10)
Tricarbonylchromium complex 2: 57 mg (100 mmol);
di-n-butyl ether: 10 ml.
1
E). H-NMR (500 MHz, CDCl3, 50 °C, ppm): l=8.11
Yield: 12 mg (21 mmol, 21%) of a light red solid.
Rf=0.54 (petroleum ether–CH2Cl2 5:6). IR (petroleum
ether, cm−1): wCO=1975 (vs, A1), 1913 (s, E), 1905 (s,
E). 1H-NMR (400 MHz, CDCl3, ppm): l=8.09 (d,
3
3
(d, JHH=9.1 Hz, 1H, H5/6), 8.07 (d, JHH=9.1 Hz,
3
1H, H5/6), 8.04 (d, JHH=7.8 Hz, 1H, H11/8), 7.81 (d,
3JHH=8.2 Hz, 1H, H8/11), 7.57 (t, JHH=7.8 Hz, 1H,
3
3
3
H9/10), 7.54–7.51 (3H, C5H6), 7.49 (t, JHH=8.2 Hz,
3JHH=9.4 Hz, 1H, H5/6), 7.51 (d, JHH=9.4 Hz, 1H,
1H, H10/9), 7.30–7.15 (7H, C5H6), 3.72 (s, 3H, OCH3),
1.03 (s, 9H, C(CH3)3), −0.02 (s, 3H, SiCH3), −0.37 (s,
3H, SiCH3). 13C-NMR (125 MHz, CDCl3, ppm): l=
233.1 (Cr(CO)3), 156.6, 149.9 (C6a, C7a), 134.9, 133.0,
132.8, 132.3, 132.0, 130.4, 130.1, 128.0 (ArCH), 127.9
(ArCH), 127.2 (ArCH), 126.9, 123.6 (ArCH), 123.5,
121.7, 121.1 (ArCH), 120.7 (ArCH), 120.3 (ArCH),
112.3 (22ArC), 108.4, 104.3, 96.9, 93.8 (C2, C3, C4a,
H5/6), 7.47 (dd, 3JHH=6.9 Hz, 4JHH=1.0 Hz, 1H,
3
4
H11), 6.18 (dd, JHH=6.9 Hz, JHH=1.0 Hz, 1H, H8),
5.56 (td, 3JHH=5.9 Hz, 4JHH=1.0 Hz, 1H, H9/10),
4.99 (td, 3JHH=6.3 Hz, 4JHH=1.0 Hz, 1H, H10/9),
2
3
3.93 (s, 3H, OCH3), 3.09 (dq, JHH=13.3 Hz, JHH
=
2
3
7.4 Hz, 1H, CH2), 2.96 (dq, JHH=13.3 Hz, JHH=7.4
Hz, 1H, CH2), 2.75 (dq, 2JHH=13.3 Hz, 3JHH=7.4 Hz,
1H, CH2), 2.67 (dq, 2JHH=13.3 Hz, 3JHH=7.4 Hz, 1H,
3
C11c), 65.8 (OCH3), 26.0 (C(C
6
H3)3), 18.8 (C
6
(CH3)3),
CH2), 1.26 (t, JHH=7.4 Hz, 3H, CH2CH3
6
), 1.25 (t,
−3.5, −4.1 (Si(CH3)2). EIMS; m/z (%): 666 (2) [M+],
582 (37) [M+−3CO], 530 (100) [M+−Cr(CO)3], 473
(86) [M+−Cr(CO)3−C(CH3)3], 458 (48) [M+−
3JHH=7.4 Hz, 3H, CH2CH3
6
), 1.15 (s, 9H, C(CH3)3),
−0.35 (s, 3H, SiCH3), −0.43 (s, 3H, SiCH3). 13C-
NMR (125 MHz, CDCl3, ppm): l=232.7 (Cr(CO)3),
157.2, 149.4, 144.2 (C1, C4, C6a), 136.7, 135.1, 132.7,
124.8, 124.6, 121.7, 116.2, 111.2 (8ArC), 97.8 (C11a),
92.8, 91.9, 85.5, 77.2 (C8, C9, C10, C11), 62.7 (OCH3),
Cr(CO)3−C(CH3)3−CH3].
HRMS:
Calc.
for
C38H34O6SiCr: 666.1529. Found: 666.1534.
26.8 (C(C
15.3 (2CH2C
6
H3)3), 21.2, 20.2 (2CH2), 18.9 (C
6
(CH3)3), 15.6,
5.6.4.2.
Tricarbonyl[(p6-1,2,3,4,4a,11c)-1-hydroxy-4-
6 H3), −2.2, −5.4 (Si(CH3)2). EIMS; m/z
methoxy-2,3-diphenylbenzo[b]naphtho[1,2-d]furan]chro-
mium (6). Yield: 0.52 g (0.94 mmol, 30%) of a red solid.
Rf=0.37 (petroleum ether–Et2O 2:1). IR (CH2Cl2,
(%): 570 (9) [M+], 514 (3) [M+−2CO], 486 (49) [M+
−3CO], 434 (96) [M+−Cr(CO)3], 419 (20) [M+−
Cr(CO)3−CH3], 377 (45) [M+−Cr(CO)3−C(CH3)3],
348 (63) [M+−Cr(CO)3−C(CH3)3−C2H5], 333 (24)
cm−1): wCO=1957 (vs, A1), 1886 (s, br, E). H-NMR
1
(500 MHz, acetone-d6, ppm): l=8.97 (d, 3JHH=8.4
[M+−Cr(CO)3−C(CH3)3−C2H5−CH3].
HRMS:
3
Hz, 1H, H11), 8.35 (d, JHH=9.3 Hz, 1H, H5/6), 8.15
Calc. for C27H34O3SiCr [M+−3CO]: 486.1651. Found:
3
3
(d, JHH=9.7 Hz, 1H, H5/6), 7.78 (d, JHH=8.4 Hz,
1H, H8), 7.60–7.15 (m, 12H, H9, H10, 2C6H5), 3.47 (s,
3H, OCH3). 13C-NMR (125 MHz, acetone-d6, ppm):
l=234.2 (Cr(CO)3), 157.3, 156.1 (C6a, C7a), 134.1,
133.0, 132.6, 132.0, 129.6, 129.5, 129.4, 128.9, 128.8,
128.6, 128.4, 128.3, 128.1, 127.3, 127.2, 126.8, 124.3,
123.6, 119.1, 114.3, 112.4, 112.1 (26ArC), 64.2 (OCH3).
EIMS; m/z (%): 552 (2) [M+], 468 (54) [M+−3CO],
416 (100) [M+−Cr(CO)3], 401 (50) [M+−Cr(CO)3−
CH3]. HRMS: Calc. for C32H20O6Cr: 552.0664. Found:
552.0673.
486.1667 (Table 5).
5.7.2. Tricarbonyl[(p6-7a,8,9,10,11,11a)-1-hydroxy-
4-methoxy-2,3-diphenylbenzo[b]naphtho[1,2-d]furan]-
chromium (11)
Tricarbonylchromium complex 6: 100 mg (181 mmol);
di-n-butyl ether: 20 ml.
Yield: 2.2 mg (4.0 mmol, 2%) of a yellow solid.
Rf=0.37 (petroleum ether–CH2Cl2 1:1). IR (petroleum
ether, cm−1): wCO=1975 (vs, A1), 1911 (s, E), 1905 (s,
1
E). H-NMR (500 MHz, acetone-d6, ppm): l=8.40 (d,

194
H.C. Jahr et al. / Journal of Organometallic Chemistry 641 (2002) 185–194
Table 5
6. Supplementary material
Atomic coordinates (×104) and equivalent isotropic displacement
2
3
,
parameters (A ×10 ) for 10
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC nos. 168735, 168736, 168737 and
168738 for compounds 1, 2, 7 and 10, respectively.
Copies of this information may be obtained free of
charge from The Director, CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK (Fax: +44-1223-336033;
e-mail: deposit@ccdc.cam.ac.uk or www: http://
www.ccdc.cam.ac.uk).
a
x
y
z
Ueq
Cr1
C1a
O1a
C1b
O1b
C1c
O1c
C1
C2
C3
C4
C4a
C5
C6
C6a
O7
C7a
C8
C9
C10
C11
C11a
C11b
C11c
O11
Si11
C12
C13
C14
C15
C16
C17
C21
C22
C31
C32
O41
C42
5269(1)
4905(1)
4672(1)
4643(1)
4253(1)
4514(1)
4039(1)
6080(1)
5836(1)
5815(1)
6041(1)
6243(1)
6448(1)
6607(1)
6534(1)
6610(1)
6417(1)
6380(1)
6180(1)
5998(1)
5986(1)
6235(1)
6335(1)
6225(1)
6183(1)
7003(1)
7610(1)
7508(1)
6765(1)
6279(2)
7500(1)
6353(2)
5565(1)
4812(1)
5585(1)
6208(1)
6015(1)
6697(1)
9350(1)
9964(2)
10350(1)
10349(2)
10990(1)
8247(2)
7553(1)
5311(2)
4246(2)
4062(2)
4970(2)
6097(2)
7023(2)
8127(2)
8321(2)
9439(1)
9319(2)
10259(2)
9985(2)
8822(2)
7911(2)
8139(2)
7486(2)
6290(2)
5422(1)
5111(1)
6448(2)
3959(2)
4627(2)
5542(2)
4490(2)
3443(2)
3307(2)
3620(2)
2895(2)
1968(2)
4833(1)
4439(2)
3529(1)
4052(1)
4373(1)
3149(1)
2910(1)
3468(1)
3420(1)
4122(1)
4278(1)
4773(1)
5086(1)
4929(1)
5265(1)
5125(1)
4637(1)
4450(1)
3968(1)
3646(1)
3163(1)
3013(1)
3346(1)
3836(1)
4286(1)
4431(1)
3649(1)
3467(1)
3511(1)
3859(1)
2825(1)
2527(1)
2620(1)
2776(1)
3914(1)
3621(1)
4958(1)
4989(1)
5568(1)
5846(1)
20(1)
28(1)
45(1)
25(1)
37(1)
30(1)
48(1)
19(1)
20(1)
21(1)
21(1)
20(1)
23(1)
24(1)
21(1)
23(1)
21(1)
25(1)
26(1)
25(1)
21(1)
19(1)
19(1)
18(1)
19(1)
21(1)
29(1)
35(1)
27(1)
45(1)
47(1)
48(1)
26(1)
35(1)
27(1)
37(1)
26(1)
38(1)
Acknowledgements
Financial support from the Deutsche Forschungsge-
meinschaft and the Fonds der Chemischen Industrie is
gratefully acknowledged.
References
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G. Lee, A.M. Gilbert, W.D. Wulff, R.G. Ball, J. Am. Chem.
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1751;
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N.A. Ustynyuk, J. Organomet. Chem. 583 (1999) 136;
(g) Y. Oprunenko, A. Malyugina, P. Nesterenko, D. Mityuk, O.
Malyshev, J. Organomet. Chem. 597 (2000) 42.
a Ueq is defined as one-third of the trace of the orthogonalized Uij
tensor.
3JHH=9.2 Hz, 1H, H5/6), 7.98 (s, 1H, OH), 7.86 (d,
3JHH=9.2 Hz, 1H, H5/6), 7.84 (dd, 3JHH=6.9 Hz,
4JHH=1.1 Hz, 1H, H11), 7.32–7.13 (m, 10H, 2C6H5),
3
4
6.56 (dd, JHH=6.9 Hz, JHH=0.9 Hz, 1H, H8), 5.98
[8] N.P. Buu-Hoi, R. Royer, Recl. Trav. Chim. 67 (1948) 175.
[9] (a) E.W. Neuse, B.R. Green, J. Organomet. Chem. 39 (1974)
585;
(b) E.W. Neuse, B.R. Green, Liebigs Ann. Chem. (1974) 1534.
[10] H. Mayr, R. Huisgen, J. Chem. Soc. Chem. Commun. (1976) 57.
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[12] G.M. Sheldrick, SHELXL-97, University of Go¨ttingen, Go¨ttingen,
Germany, 1997.
3
4
(td, JHH=6.6 Hz, JHH=1.1 Hz, 1H, H9), 5.29 (td,
3JHH=6.4 Hz, JHH=0.9 Hz, 1H, H10), 3.47 (s, 3H,
4
OCH3). 13C-NMR (125 MHz, acetone-d6, ppm): l=
234.5 (Cr(CO)3), 137.8–112.1 (ArC), 95.8, 95.3, 88.7,
79.3 (C8, C9, C10, C11), 61.9 (OCH3). EIMS; m/z (%):
416 (6) [M+−Cr(CO)3], 400 (100) [C28H16O+3 ].