Dichotomies in microwave-assisted propargyl-isomerization-Claisen domino sequences dependent on base strengths

Article abstract of DOI:10.1039/b714351f

Microwave-assisted unimolecular isomerization-Claisen domino reactions of 1,3-di(hetero)aryl propargyl trityl ethers lead, depending on the basicity of the amine, either to the formation of tricyclo[3.2.1.0^2,7]oct-3-enes (with triethylamine) or to indanes (with DBU). Based upon product analyses and computations, this base dependent dichotomy can be rationalized as a sequel of pericyclic reactions with intermediate protonation and deprotonation. The Royal Society of Chemistry 2008.

Full text of DOI:10.1039/b714351f

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Dichotomies in microwave-assisted propargyl-isomerization–Claisen domino
sequences dependent on base strengths†‡
Daniel M. D’Souza,a Wei-Wei Liao,a Frank Romingera and Thomas J. J. Mu¨ller*a,b
Received 17th September 2007, Accepted 26th November 2007
First published as an Advance Article on the web 17th December 2007
DOI: 10.1039/b714351f
Microwave-assisted unimolecular isomerization–Claisen domino reactions of 1,3-di(hetero)aryl
propargyl trityl ethers lead, depending on the basicity of the amine, either to the formation of
tricyclo[3.2.1.02,7]oct-3-enes (with triethylamine) or to indanes (with DBU). Based upon product
analyses and computations, this base dependent dichotomy can be rationalized as a sequel of pericyclic
reactions with intermediate protonation and deprotonation.
Introduction
In the past few years, the concept of domino reactions1 has
become almost synonymous for the rapid construction of complex
structural frameworks in a one-pot fashion. With regard to syn-
thetic efficiency and efficacy, reactive functionalities are generated
and transformed in a programmed fashion without altering the
reaction conditions nor adding further reagents or catalysts.
Therefore, mastering unusual combinations and sequences of ele-
mentary organic reactions under identical conditions remains the
major conceptual challenge in engineering novel types of domino
sequences. Based upon the coupling–isomerization reaction2
(CIR)—a Sonogashira coupling of electron deficient (hetero)aryl
halides and (hetero)aryl propargyl alcohols followed by a base
catalyzed transformation of the intermediate internal 3-aryl
Scheme 1 Dichotomies in CI–Claisen domino sequences.
should render a deeper insight into the parameters of the new
domino sequences. Here, we report on a series of unimolecular
isomerization–Claisen domino sequences triggered by microwave
heating and two bases with different base strengths.
propargyl alcohol into a 1,3-aryl propenone—we have developed,
in recent years, consecutive multi-component heterocycle synthe-
ses initiated by transition metal catalysis3 giving rise to efficient
and diverse syntheses of pharmaceutically relevant heterocycles
in a one-pot fashion.4 Furthermore, a mechanistic expansion of
CIR by etherification of the propargyl alcohol and intramolecular
carbopalladation led to the formation of a new class of highly
fluorescent spirocyclic benzofuranones and dihydroindolones.5
However, propargyl trityl ethers as alkynyl substrates set the
stage for a whole multitude of domino sequels that, after CIR
and Claisen rearrangement, culminated in dichotomizing final
pericyclic steps with high selectivity as a consequence of minute
electronic differences in the substitution pattern (Scheme 1).6
Since CIR can be considerably accelerated by microwave
heating7 and encouraged by the amazing and highly selective bi-
furcation in the concluding steps of CI–Claisen domino reactions,6
the influence of dielectric heating and variation of the base strength
Results and discussion
In all CIR based domino sequences, the cross-coupling event is
always rapid in comparison to the isomerization step. Therefore,
it is reasonable to treat both elementary steps separately and,
thus, 1,3-di(hetero)aryl propargyl trityl ethers 1 are logical starting
substrates for unimolecular sequences. Upon reaction of propargyl
trityl ethers 1 in a 1 : 1 mixture of butyronitrile and triethylamine
under microwave heating in a sealed vessel, tricyclo[3.2.1.02,7]oct-
3-enes 2 were formed as sole products in excellent yields, whereas
in a 1 : 1 mixture of DMSO and DBU, dielectric heating in a
sealed vessel led to the selective formation of indanes 3 in good to
excellent yields (Scheme 2, Table 1 and Table 2).
The structures of the tricyclo[3.2.1.02,7]oct-3-enes 2 and the
indanes 3 were unambiguously supported by spectroscopic (1H,
13C and DEPT, COSY, NOESY, HETCOR and HMBC NMR
experiments, IR, UV–Vis, mass spectrometry) and combustion
analyses. Additionally, the molecular structure of 2 was corrobo-
rated by X-ray structure analyses of compounds 2a (Fig. 1) and
2c (Fig. 2).§
aOrganisch-Chemisches Institut, Ruprecht-Karls-Universita¨t Heidelberg, Im
Neuenheimer Feld 270, 69121 Heidelberg, Germany
bInstitut fu¨r Organische Chemie und Makromolekulare Chemie, Heinrich-
Heine-Universita¨t Du¨sseldorf, Universita¨tsstrasse 1, 40225 Du¨sseldorf,
Germany. E-mail: ThomasJJ.Mueller@uni-duesseldorf.de; Fax: +221 81
12298; Tel: +221 81 14324
† Electronic supplementary information (ESI) available: X-Ray structure
data of 2a, 2c, 11eand 11f; computational studies on the intermediates and
products. See DOI: 10.1039/b714351f
‡ CCDC reference numbers 660693, 660694, 641143 and 641144. For
crystallographic data in CIF or other electronic format see DOI:
10.1039/b714351f
§ Data were collected on a Bruker Smart CCD (2c) or a Bruker APEX
˚
diffractometer (2a, 11e, 11f). Mo Ka radiation (k = 0.71073 A) was used in
532 | Org. Biomol. Chem., 2008, 6, 532–539
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Table 1 Microwave-assisted isomerization–Claisen rearrangement–
Diels–Alder domino sequence to tricyclo[3.2.1.02,7]oct-3-enes 2a
Entry
Tricyclo[3.2.1.02,7]oct-3-ene 2 (yield)b
1c
2d
3
4
5
2a (aryl1 = p-O2NC6H4, 85%)
2b (aryl1 = p-MeO2CC6H4, 83%)
2c (aryl1 = p-NCC6H4, 92%)
2d (aryl1 = p-MeC6H4, 0%)
2e (aryl1 = p-MeOC6H4, 0%)
a Reaction conditions: 1 (0.2 M in butyronitrile–triethylamine 1 : 1), was
dielectrically heated at 135 ◦C for 30 min in a sealed vial. b Yields refer to
isolated yields of tricyclo[3.2.1.02,7]oct-3-enes 2 after flash chromatography
on silica gel and were ≥95% pure as determined by NMR spectroscopy
and elemental analysis. c After conductive heating in a coupling sequence
and after isolation and recrystallization, a 91% yield of 2a was obtained.
d After conductive heating in a coupling sequence and after isolation and
recrystallization, a 85% yield of 2b was obtained.
Fig. 1 Molecular structure of tricyclo[3.2.1.02,7]oct-3-ene 2a (hydrogen
atoms were omitted for clarity, ORTEP: 50% probability).
Table 2 Microwave-assisted isomerization–Claisen rearrangement–
deprotonation–electrocyclization–protonation domino sequence to
indanes 3a
Entry
Indane 3 (yield)b
1c
2
3a (aryl1 = p-MeO2CC6H4, 80%)
3b (aryl1 = Ph, 94%)
3d
4e
5
3c (aryl1 = p-NCC6H4, 62%)
3c (aryl1 = Ph, 92%)
3d (aryl1 = p-MeC6H4, 82%)
6
3e (aryl1 = p-MeOC6H4, 62%)
a Reaction conditions: 1 (0.2 M in DMSO) and 1.6 eq DBU were
dielectrically heated at 130 ◦C for 20 min in a sealed vial. b Yields refer
to isolated yields of indanes 3 after flash chromatography on silica gel
and were ≥95% pure as determined by NMR spectroscopy and elemental
analysis. c The reaction was carried out in butyronitrile and 1.15 eq DBU
at 100 ◦C for 18 min. d The reaction was carried out at 120 ◦C for 5 min.
e The reaction was carried out in butyronitrile under otherwise identical
conditions.
Fig. 2 Molecular structure of tricyclo[3.2.1.02,7]oct-3-ene 2c (hydrogen
atoms were omitted for clarity, ORTEP: 50% probability).
In consistency with the CI process carried out under con-
ductive heating and in the presence of NEt3 as the base,
◦
3
˚
˚
c = 22.612(4) A, b = 109.831(3) , V = 2874.9(7) A , T = 100(2) K,
Z = 4, q = 1.◦28 g cm−3, dimensions 0.43 × 0.065 × 0.04 mm3, l =
0.08 mm−1, 0.3 omega-scans, 16360 reflections measured, 3488 unique
[R(int) = 0.0536], 2697 observed [I > 2r(I)], 509 parameters refined,
goodness of fit 1.04, wR2 = 0.107, R1 = 0.048 (observed reflections),
residual electron density −0.59 to 0.54 eA−3, CCDC 660693. 2c: C35H25NO,
˚
¯
M = 475.6, triclinic, space group P1, a = 12.1762(2), b = 17.4◦387(2),
◦
◦
˚
c = 20.1060(1) A, a = 80.239(1) , b = 73.766(1) , c = 73.137(1) , V =
3904.56(8) A , T = 200(2) K, Z = 6, q = 1.21 g cm−3, crystal dimensions
3
˚
0.40 × 0.24 × 0.08 mm3, l = 0.07 mm−1, 0.3◦ omega-scans, 26587
reflections measured, 10487 unique [R(int) = 0.0491], 7415 observed [I >
2r(I)], 1000 parameters refined, goodness of fit 1.03, wR2 = 0.107, R1 =
−3
˚
0.049 (observed reflections), residual electron density −0.23 to 0.37 eA
,
¯
CCDC 641143. 11e: C29H24O, M = 388.5, triclinic, space group P1,
◦
˚
a = 8.5190(2), b = 12.5850(3), c = 10.2410(1) A, a = 73.0570(1) , b =
◦
◦
3
˚
86.7680(1) , c = 98.8770(9) , V = 1031.73(4) A , T = 200(2) K, Z = 2,
q = 1.25 g cm−3, crystal dimensions 0.49 × 0.17 × 0.06 mm3, l = 0.07 mm−1
,
0.3◦ omega-scans. The crystals turned out to be partially merohedrically
twinned, so an artificially enlarged unit cell had to be used to be able to
integrate all the reflections, 6151 reflections of solely component A, 6201
reflections of solely component B, and 2026 reflections belonging to both
components result in 14378 observations measured, 9690 observed [I >
2r(I)], 3505 after merging equivalents, 285 parameters refined, goodness
of fit 1.22, wR2 = 0.110, R1 = 0.048 (observed reflections), residual
Scheme 2 Base dependent dichotomy in microwave-assisted isomeriza-
tion–Claisen domino sequences.
all cases and the intensities were corrected for absorption effects using
SADABS14 based on the laue symmetry of the reciprocal space. The
structures were solved by direct methods and refined against F2 with a full
matrix least square algorithm by using the SHELXTL14 software package.
Hydrogen atoms were partially refined isotropically (at the core of 11e),
otherwise they were considered at calculated positions and refined using
appropriate riding models. Relevant crystal and data collection parameters
for the individual structures are given here. Crystal data: 2a: C37H31NO4,
M = 553.63, monoclinic, space group P21/c, a = 15.348(2), b = 8.806(1),
electron density −0.17 to 0.17 eA−3, CCDC 641144. 11f: C29H24O2, M =
˚
404.48, orthorhombic, space group Pccn, a = 15.277(3), b = 37.640(8), c =
3
−3
˚
˚
7.251(2) A, V = 4169.4(15) A , T = 200(2) K, Z = 8, q = 1.289 g cm
,
dimensions 0.18 × 0.12 × 0.05 mm3, l = 0.08 mm−1, 0.3◦ omega-scans,
10547 reflections measured, 2173 unique [R(int) = 0.0737], 1621 observed
[I > 2r(I)], 281 parameters refined, goodness of fit 1.08, wR2 = 0.133, R1 =
−3
˚
0.061 (observed reflections), residual electron density −0.20 to 0.21 eA
,
CCDC 660694.
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tricyclo[3.2.1.02,7]oct-3-enones 2 are the products of the in-
tramolecular isomerization–Claisen sequence. However, increas-
ing the base strength from NEt3 (pKb = 3.35) to DBU (pKb = 1.16)
favors the formation of indanes 3. Furthermore, the stronger base
DBU obviously also triggers the propyne–allene isomerization
which does not occur with electron-donating aryl substituents in
the 3-position when applying NEt3 as the base (Table 1, entries 4
and 5 vs. Table 2, entries 3–6).
However, the concluding steps in this domino sequence seem to
be relatively complex. For an insight into the energetic scenario,
quantum chemical calculations on structures and energies of the
propargyl trityl ether 1c, the tentative intermediates 4c and 5c, and
the possible reaction products 2c, 3c, and 6c were carried out on
high levels of theory (Fig. 3).8
Geometry optimizations were carried out using Becke Perdew
(BP) 86 functionals [RBP86/6-31+G(d,p)]9 and based upon
single point energy calculations using the Møller–Plesset cor-
relation energy correction truncated at second-order [RMP2/6-
311++G(2d,2p)//RBP86/6-31+G(d,p)],10 energetic estimations
propose some profound mechanistic implications. Starting from
the propargyl trityl ether 1c, isomerization of the alkyne furnishes
the allenyl trityl ether 4c with a thermodynamic driving force
of 5.75 kcal mol−1. This allenyl intermediate is quite in agree-
ment with other sequences that are based upon the coupling–
isomerization reaction.2,5,6 Then, intermediate 4c sets the stage
for an allenyl–benzyl Claisen rearrangement giving rise to the
formation of a exo-methylene cyclohexadiene enone 5c, which
is less than 1 kcal mol−1 more stable than 4c. According to the
product analysis, now, the bifurcation takes place. Computing
the energies of the possible products, which are indeed observed
under special conditions, i.e. tricyclo[3.2.1.02,7]oct-3-ene 2c (under
microwave irradiation and with triethylamine as a base), 2-
substituted triphenylmethyl enone 6c (under conductive heating
and with triethylamine as a base),6 and indane 3c (under microwave
irradiation and with DBU as a base), reveals interesting aspects
of this sequence. Obviously, the thermodynamically most stable
isomer is indane 3c (−61.23 kcal mol−1) and it is only formed at
higher temperatures (microwave heating) and if the base is strong
enough (DBU). Interestingly, the thermodynamically more favor-
able enone 6c (−44.41 kcal mol−1) is not formed if the energy is
just high enough (microwave heating) to trigger an intramolecular
[4 + 2]-cycloaddition as a kinetically controlled formation of the
least favorable tricyclo[3.2.1.02,7]oct-3-ene 2c (−20.46 kcal mol−1).
Only prolonged conductive heating furnishes the more stable
isomer 6c if the base is triethylamine. However, under dielectric
heating in combination with sufficient base strength, kinetic
control is apparently dominating by rapid energy transfer to the
reactants in the vessel. Here again, as reported before,6 minute elec-
tronic differences in combination with the mode of heating and the
basicity determine the bifurcation of isomerization–pericyclic se-
quences. Hence, triethylamine as a base is definitely strong enough
to catalyze the isomerization from alkyne 1 to allene 4, but it fails
to catalyze the isomerization from Claisen rearrangement product
5 to indane 3 or enone 6c. This can be accounted for by the inter-
mediacy on an anion generated upon deprotonation with a suffi-
ciently strong base. Otherwise, if no anion can be rapidly gener-
ated, the obvious reaction is the fast intramolecular cycloaddition
that should proceed at higher rates than intermolecular processes.
Fig. 3 Computed energies (RBP86/6-31+G(d,p) for geometries and RMP2/6-311++G(2d,2p)//RBP86/6-31+G(d,p) for energies) of the propargyl
trityl ether 1c, the tentative intermediates 4c and 5c, and possible reaction products 2c, 3c, and 6c.
534 | Org. Biomol. Chem., 2008, 6, 532–539
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Table 3 Isomerization–Claisen rearrangement–deprotonation–electro-
cyclization–protonation domino sequence to 1-(hetero)aroyl 3,3-diphenyl-
indanes 11a
Based upon these energetic considerations, the tentative mech-
anism of these bifurcating domino reactions can be rationalized
as follows (Scheme 3).
Entry
1-(Hetero)aroyl 3,3-diphenylindane 5 (yield)b
1c
2
11a ((het)aryl = p-NCC6H4, 33%)
11b ((het)aryl = p-ClC6H4, 94%)
11c ((het)aryl = C6H5, 94%)
3
4d
5
11d ((het)aryl = 2-thienyl, 84%)
11e ((het)aryl = p-MeC6H4, 90%)
11f ((het)aryl = p-MeOC6H4, 92%)
11g ((het)aryl = p-nhexylOC6H4, 89%)
6
7e
a Reaction conditions: 4 (0.2 M in DMSO) and 1.6 eq of DBU were
dielectrically heated at 150 ◦C for 20 min in a sealed vial. b Yields refer
to isolated yields of indanes 5 after flash chromatography on silica gel
and were ≥95% pure as determined by NMR spectroscopy and elemental
analysis. c The reaction was carried out in butyronitrile using 1.6 eq DBU
at 120 ◦C for 15 min. d The reaction was carried out at 130 ◦C for 10 min.
e The reaction was carried out at 150 ◦C for 15 min.
Scheme
4
Microwave-assisted
isomerization–Claisen–cyclization
domino sequence to 1-(hetero)aroyl 3,3-diphenylindanes 11.
Scheme 3 Mechanistic rationale for the base dependent dichotomy in
microwave-assisted isomerization–Claisen domino sequences.
After the propyne–allene isomerization–Claisen rearrangement,
the cyclohexadienyl proton is susceptible to deprotonation with
a sufficiently strong base. The presence of a weak base leads
to an intramolecular [4 + 2] cycloaddition that immediately es-
tablishes the tricyclo[3.2.1.02,7]oct-3-ene framework of 2, whereas
deprotonation with DBU generates delocalized carbanions 7
and 8, which are prone to cis–trans interconversion. However,
the carbanion isomer 8 culminates in a 6p-electrocyclization
with concomitant rearomatization and generation of enolate 9.
Finally, protonation of 9 gives rise to the formation of the
thermodynamically most stable anti-configured indane 3. Hence,
if equilibration is possible, the thermodynamic outcome of an
isomerization–Claisen sequence with 1 as a substrate is always the
indane motif 3.
As a consequence, we also tested whether an aryl substituent
in the 3-position of 1 is necessary at all to favor the generation of
indane derivatives. Therefore, trityl ethers 10 with terminal alkyne
functionality were submitted to the isomerization conditions
in DMSO and with DBU as a base to selectively furnish 1-
(hetero)aroyl 3,3-diphenylindanes 11 in moderate to excellent
yields (Scheme 4, Table 3).
The unambiguous structural assignments were based on ex-
tensive spectroscopic and combustion analyses. Additionally, the
molecular structure of 11 was corroborated by X-ray structure
analyses of compounds 11e (Fig. 4) and 11f (Fig. 5).§
Fig. 4 Molecular structure of 1-(hetero)aroyl 3,3-diphenylindane 11e
(most hydrogen atoms were omitted for clarity, ORTEP: 50% probability).
Conclusions
In conclusion, we have found that base strength exercises a consid-
erable influence in microwave-assisted dichotomizing unimolecu-
lar isomerization–Claisen sequences. Particularly, computations
and product analyses support the tentative mechanistic rationale
where bifurcation occurs after the Claisen step as a consequence
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microanalytical laboratory of the Organisch-Chemisches Institut
der Universita¨t Heidelberg.
General procedure for the synthesis of terminal propargyl trityl
ethers 10 and internal propargyl trityl ethers 1
Synthesis of compounds 10. A detailed experimental procedure
for the synthesis of compounds 10 has been previously published.6
Synthesis of compounds 1. To a deaerated mixture of a
magnetically stirred THF solution of compound 7 and 1.00
equivalent of the corresponding aryl halides in a Schlenk flask
with a positive nitrogen atmosphere was gradually added 5
mol% of PdCl2(PPh3)2, 5 mol% of CuI, and 1.05 equivalents of
triethylamine. The reaction mixture was stirred at room temp until
complete consumption of the aryl halide (monitored by TLC). For
work up, the reaction mixture was diluted with ether, submitted to
filtration for removal of the ammonia salts and the solvents were
evaporated in vacuo. The residue was filtered on silica gel (hexane–
ethyl acetate 10 : 1 up to 5 : 1) to give the internal propargyl trityl
ethers 1 in quantitative yields as light yellow solids, which were
submitted to the isomerization–Claisen sequences without further
purification.
General procedure for the isomerization–Claisen sequences to the
products 2, 3, or 11
A magnetically stirred deaerated solution of compound 1 or 4
(0.3 mmol) in 3.0 mL of a mixture of butyronitrile and NEt3 (1 : 1,
v/v) was dielectrically heated in a sealed microwave vial at 135 ◦C
for 30 min (see Table 4 for experimental details). After cooling
to rt, the solvents were removed in vacuo, and the residue was
chromatographed on silica gel to give rise to the desired products
2, 3, or 11, respectively.
Fig. 5 Molecular structure of 1-(hetero)aroyl 3,3-diphenylindane 11f
(most hydrogen atoms were omitted for clarity, ORTEP: 50% probability).
of the generation of anionic intermediates in the presence of
sufficiently strong bases. Interestingly, excellent chemoselectivities
underline the well balanced electronic interplay in concluding
pericyclic steps. Both tricyclo[3.2.1.02,7]oct-3-enes 2 and indanes
3 or 11 are intriguing frameworks and are suitable for synthetic
and methodological elaboration. In particular, highly substituted
indanes display biological activity such as pharmacological11 and
olfactory properties.12 Studies addressing the synthetic scope of
these new domino reactions are currently under investigation.
Table 4 Experimental details of CI–Claisen sequencesa
Entry Propargyl trityl ether 1 or 7 Sequence products 2, 3, or 11 (yield)b
1a
2b
3
149 mg (0.3 mmol) of 1a
153 mg (0.3 mmol) of 1b
143 mg (0.3 mmol) of 1c
153 mg (0.3 mmol) of 1b
143 mg (0.3 mmol) of 1c
135 mg (0.3 mmol) of 1d
139 mg (0.3 mmol) of 1e
144 mg (0.3 mmol) of 1f
120 mg (0.3 mmol) of 4a
123 mg (0.3 mmol) of 4b
112 mg (0.3 mmol) of 4c
114 mg (0.3 mmol) of 4d
117 mg (0.3 mmol) of 4e
121 mg (0.3 mmol) of 4f
142 mg (0.3 mmol) of 4g
127 mg (85%) of 2a
127 mg (83%) of 2b
131 mg (92%) of 2c
122 mg (80%) of 3a
89 mg (62%) of 3b
127 mg (94%) of 3c
114 mg (82%) of 3d
89 mg (62%) of 3e
40 mg (33%) of 11a
116 mg (94%) of 11b
105 mg (94%) of 11c
96 mg (84%) of 11d
105 mg (90%) of 11e
111 mg (92%) of 11f
126 mg (89%) of 11g
4c
5d
6e
7e
8e
9f
Experimental
General considerations. All reactions involving water-sensitive
compounds were carried out in oven-dried vials under a nitrogen
atmosphere. The solvents were dried according to standard
procedures13 and were distilled prior to use. Column chro-
matography: silica gel 60 M (mesh 230–400) Macherey-Nagel.
Thin layer chromatography (TLC): silica gel layered aluminium
foil (60 F254 Merck, Darmstadt). Melting points (uncorrected):
Reichert-Jung Thermovar and Bu¨chi Melting Point B-540. 4-
Iodobenzonitrile 4 was purchased from ACROS and used without
further purification. Trityl propargyl ethers 2 were prepared from
10
11
12g
13
14
15h
a Yields of a thermal conventionally heated bimolecular reaction after
isolation and recrystallization (91%). b Yields of a thermal conventionally
heated bimolecular reaction after isolation and recrystallization (85%).
c The reaction was carried out in butyronitrile and 1.15 eq DBU at 100 ◦C
for 18 min. d The reaction was carried out in DMSO and 1.6 eq DBU at
120 ◦C for 5 min. e The reaction was carried out in DMSO and 1.6 eq DBU
at 130 ◦C for 20 mi◦n. f The reaction was carried out in butyronitrile using
1.6 eq DBU at 120 C for 15 min. g The reaction was carried out at 130 ◦C
for 10 min. h The reaction was carried out at 150 ◦C for 15 min.
propargyl alcohols obtained by literature procedures.2 1H and 13
C
NMR spectra: Bruker ARX250, Bruker DRX 300 with CDCl3
as solvent. The assignments of quaternary C, CH, CH2 and CH3
were made on the basis of DEPT spectra. IR: Bruker Vector 22
FT-IR. UV–Vis: Hewlett Packard HP8452 A. MS: Jeol JMS-700
und Finnigan TSQ 700. Elemental analyses were carried out in the
536 | Org. Biomol. Chem., 2008, 6, 532–539
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6-Benzhydrylidene-8-(4-nitro-phenyl)-tricyclo[3.2.1.02,7]-
oct-3-en-1-yl]-phenyl-methanone (2a)
J = 7.0 Hz, 2 H), 6.79–6.77 (m, 1 H), 6.85 (d, J = 8.0 Hz, 2 H),
7.04–6.99 (m, 3 H), 7.24–7.13 (m, 3 H), 7.30–7.27 (m, 1 H), 7.39–
7.36 (m, 2 H), 7.50–7.47 (m, 2 H), 7.61–7.58 (m, 3 H), 7.65 (d,
J = 8.0 Hz, 2 H), 8.01 (d, J = 7.0 Hz, 2 H). 13C NMR (125 MHz,
CDCl3): d 51.9 (CH), 53.5 (CH3), 58.2 (CH), 65.7 (Cquat), 123.6
(CH), 126.6 (CH), 126.7 (CH), 126.7 (CH), 127.1 (CH), 127.5
(CH), 128.2 (CH), 128.2 (CH), 128.6 (Cquat), 128.8 (CH), 128.9
(CH), 128.9 (CH), 129.2 (CH), 129.4 (CH), 130.5 (CH), 133.6
(CH), 137.8 (Cquat), 140.9 (Cquat), 141.4 (Cquat), 143.8 (Cquat), 144.7
(Cquat), 149.3 (Cquat), 166.9 (Cquat), 198.6 (Cquat). EI MS (70 eV, m/z
(%)): 508 (M+, 52), 403 (M+ − C6H5CO, 100); HRMS (70 eV, EI)
calcd for C36H28O3: 508.2038; found, 508.2015. IR (KBr) mmax 1722,
1682, 1600 cm−1. Anal. calcd. for C36H28O3 (508.6): C, 85.01; H,
555; found: C, 85.05; H, 5.59%.
Mp. 174–176 ◦C. 1H NMR (300 MHz, CDCl3): d 2.95–2.92 (m, 1
H), 3.25–3.21 (m, 1 H), 3.65–3.61 (m, 1 H), 4.14 (d, J = 6.0 Hz, 1
H), 5.61–5.55 (m, 1 H), 6.27–7.22 (m, 1 H), 7.17 (d, J = 7.8 Hz, 2
H), 7.51–7.24 (m, 13 H), 7.71–7.68 (m, 2 H), 7.97 (d, J = 9.0 Hz,
2 H). 13C NMR (125 MHz, CDCl3): d 27.5 (CH), 33.2 (CH),
43.3 (Cquat), 45.8 (CH), 46.8 (CH), 123.0 (CH), 125.2 (CH), 126.1
(CH), 127.2 (CH), 127.4 (CH), 127.5 (CH), 128.2 (CH), 128.3
(CH), 128.5 (CH), 129.1 (CH), 129.7 (CH), 129.8 (CH), 132.3
(CH), 136.3 (Cquat), 137.0 (Cquat), 138.2 (Cquat), 141.6 (Cquat), 146.2
(Cquat), 146.5 (Cquat), 199.9 (Cquat). EI MS (70 eV, m/z (%)): 495 (M+,
+
100), 165 (C13H9 , 51); HRMS (70 eV, EI) calcd. for C34H25NO3:
495.1834; found, 495.1822. IR (KBr) 1666, 1598, 1517 cm−1. Anal.
calcd. for C34H25NO3 (495.6): C, 82.40; H, 5.08; N, 2.83; found: C,
82.04; H, 5.52; N, 2.69%.
Phenyl-(2,3,3-triphenyl-indan-1-yl)-methanone (3b)
◦
1
Mp. 178–179 C. H NMR (300 MHz, CDCl3): d 5.35 (d, J =
10.5 Hz, 1 H), 5.59 (d, J = 9.9 Hz, 1 H), 6.35–6.32 (m, 2 H),
6.79–6.74 (m, 3 H), 7.04–6.94 (m, 6 H), 7.23–7.12 (m, 3 H), 7.29–
7.27 (m, 1 H), 7.39–7.34 (m, 2 H), 7.50–7.45 (m, 2 H), 7.63–7.58
(m, 3 H), 8.03–8.00 (m, 2 H). 13C NMR (75 MHz, CDCl3): d
53.5 (CH), 58.3 (CH), 65.5 (Cquat), 123.6 (CH), 126.4 (CH), 126.5
(CH), 126.6 (CH), 126.8 (CH), 127.4 (CH), 127.6 (CH), 128.0
(CH), 128.0 (CH), 128.8 (CH), 128.9 (CH), 129.3 (CH), 130.6
(CH), 133.4 (CH), 138.0 (Cquat), 138.1 (Cquat), 141.2 (Cquat), 141.8
(Cquat), 145.1 (Cquat), 149.6 (Cquat), 199.0 (Cquat). EI MS (70 eV, m/z
(%)): 450 (M+, 51), 345 (M+ − C6H5CO, 100); HRMS (70 eV, EI)
calcd for C34H26O: 450.1984; found, 450.2014. IR (KBr) mmax 1686,
1579 cm−1. Anal. calcd. for C34H26O (450.6): C, 90.63; H, 5.82;
found: C, 90.41; H, 5.91%.
4-(8-Benzhydrylidene-7-benzoyl-tricyclo[3.2.1.02,7]oct-3-en-6-yl)-
benzoic acid methyl ester (2b)
◦
1
Mp. 197–199 C. H NMR (300 MHz, CDCl3): d 2.87 (dd, J =
7.9 Hz, J = 1.2 Hz, 1 H), 3.25–3.20 (m, 1 H), 3.63–3.59 (m, 1
H), 3.82 (s, 3 H), 4.10 (d, J = 4.5 Hz, 1 H), 5.59–5.53 (m, 1
H), 6.23–6.18 (m, 1 H), 7.07 (d, J = 8.1 Hz, 2 H), 7.44–7.22 (m,
13 H), 7.69–7.67 (m, 2 H), 7.77 (d, J = 8.7 Hz, 2 H). 13C NMR
(125 MHz, CDCl3): d 27.4 (CH), 33.5 (CH), 43.3 (Cquat), 45.8 (CH),
46.9 (CH), 51.9 (CH3), 125.0 (CH), 126.1 (CH), 126.3 (CH), 127.2
(CH), 127.5 (CH), 128.1 (CH), 128.2 (CH), 128.3 (CH), 128.4
(CH), 129.1 (CH), 129.8 (CH), 129.8 (CH), 132.1 (CH), 135.9
(Cquat), 137.7 (Cquat), 138.5 (Cquat), 141.7 (Cquat), 141.7 (Cquat), 143.7
(Cquat), 166.8 (Cquat), 200.4 (Cquat). EI MS (70 eV, m/z (%)): 508
(M+, 100), 165 (M+ − C6H5CO, 52); HRMS (70 eV, EI) calcd. for
C36H28O3: 508.2038; found, 508.2043. IR (KBr) 1724, 1669, 1611,
1598 cm−1. Anal. calcd. for C36H28O3 (508.6): C, 85.01; H, 5.55;
found: C, 84.89; H, 5.59%.
4-(3-Benzoyl-1,1-diphenyl-indan-2-yl)-benzonitrile (3c)
◦
1
Mp. 176–178 C. H NMR (300 MHz, CDCl3): d 5.32 (d, J =
10.5 Hz, 1 H), 5.64 (d, J = 10.8 Hz, 1 H), 6.32 (d, J = 8.5 Hz, 2 H),
6.79–6.77 (m, 1 H), 6.88 (d, J = 8.0 Hz, 2 H), 7.08–6.99 (m, 3 H),
7.41–7.15 (m, 8 H), 7.63–7.49 (m, 5 H), 8.02 (d, J = 8.0 Hz, 2 H).
13C NMR (75 MHz, CDCl3): d 53.4 (CH), 57.8 (CH), 65.7 (Cquat),
110.6 (Cquat), 118.8 (Cquat), 123.6 (CH), 126.6 (CH), 126.9 (CH),
126.9 (CH), 127.2 (CH), 127.6 (CH), 128.3 (CH), 128.4 (CH),
128.9 (CH), 129.0 (CH), 129.1 (CH), 130.0 (Cquat), 130.4 (CH),
131.3 (CH), 133.8 (CH), 137.6 (Cquat), 140.4 (Cquat), 141.2 (Cquat),
144.1 (Cquat), 144.3 (Cquat), 149.0 (Cquat), 198.1 (Cquat). EI MS (70 eV,
m/z (%)): 475 (M+, 83), 370 (M+ − C6H5CO, 100); HRMS (70 eV,
EI) calcd for C35H25NO: 475.1936; found, 475.1938. IR (KBr) mmax
2233, 1682, 1618, 1608 cm−1. Anal. calcd. for C35H25NO (575.2):
C, 88.39; H, 5.30; N, 2.95; found: C, 88.36; H, 5.29; N, 2.93%.
4-(8-Benzhydrylidene-7-benzoyl-tricyclo[3.2.1.02,7]oct-3-en-6-yl)-
benzonitrile (2c)
◦
1
Mp. 174–176 C. H NMR (300 MHz, CDCl3): d 2.90 (d, J =
7.4 Hz, 1 H), 3.20 (m, 1 H), 3.60 (m, 1 H), 4.10 (d, J = 4.2 Hz, 1
H), 5.57 (m, 1H), 6.24–6.21 (m, 1 H), 7.12 (d, J = 8.1 Hz, 2 H),
7.48–7.24 (m, 15 H), 7.69 (d, J = 7.2 Hz, 2 H). 13C NMR (75 MHz,
CDCl3): d 27.4 (CH), 33.1 (CH), 43.1 (Cquart), 45.7 (CH), 46.9
(CH), 110.1 (Cquart), 118.8 (Cquart), 125.1 (CH), 126.1 (CH), 127.2
(CH), 127.3 (CH), 127.5 (CH), 128.1 (CH), 128.2 (CH), 128.5
(CH), 129.0 (CH), 129.7 (CH), 131.5 (CH), 132.2 (CH), 136.2
(Cquart), 137.1 (Cquart), 138.2 (Cquart), 141.6 (Cquart), 141.6 (Cquart),
143.9 (Cquart), 199.9 (Cquart). EI MS (70 eV, m/z (%)): 475 (M+, 100),
307 (M+ − C6H5CO, 53). HRMS (70 eV, EI) calcd. for C35H25NO:
475.1936; found: 475.1954. IR (KBr): mmax 3045 (w), 2227 (s), 1668
(s), 1608 (s), 1598 (s) cm−1. Anal. calcd. for C35H25NO (575.2): C,
88.39; H, 5.30; N, 2.95; found: C, 88.26; H, 5.34; N 2.95%.
(3,3-Diphenyl-2-p-tolyl-indan-1-yl)-phenyl-methanone (3d)
◦
1
Mp. 184–186 C. H NMR (300 MHz, CDCl3): d 2.17 (s, 3 H),
5.30 (d, J = 10.8 Hz, 1 H), 5.53 (d, J = 11.1 Hz, 1 H), 6.35 (d,
J = 6.9 Hz, 2 H), 6.65 (d, J = 8.7 Hz, 2 H), 6.79–6.76 (m, 3 H),
7.06–6.97 (m, 3 H), 7.19–7.13 (m, 3 H), 7.29–7.24 (m, 1 H), 7.37–
7.38 (m, 2 H), 7.50–7.45 (m, 2 H), 7.61–7.56 (m, 3 H), 8.00 (d, J =
7.5 Hz, 2 H). 13C NMR (75 MHz, CDCl3): d 21.0 (CH3), 53.6 (CH),
58.2 (CH), 65.4 (Cquat), 123.6 (CH), 126.3 (CH), 126.5 (CH), 126.6
(CH), 126.8 (CH), 127.3 (CH), 128.0 (CH), 128.0 (CH), 128.2
(CH), 128.8 (CH), 128.9 (CH), 129.3 (Cquat), 129.4 (CH), 130.7
4-(3-Benzoyl-1,1-diphenyl-indan-2-yl)-benzoic acid methyl ester
(3a)
◦
1
Mp. 204–205 C. H NMR (500 MHz, CDCl3): d 3.81 (s, 3 H),
5.35 (d, J = 11.0 Hz, 1 H), 5.62 (d, J = 10.5 Hz, 1 H), 6.33 (d,
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(CH), 133.4 (CH), 134.9 (Cquat), 136.3 (Cquat), 138.1 (Cquat), 141.4
(Cquat), 142.0 (Cquat), 145.2 (Cquat), 149.7 (Cquat), 199.1 (Cquat). EI
MS (70 eV, m/z (%)): 464 (M+, 37), 359 (M+ − C6H5CO, 100);
HRMS (70 eV, EI) calcd for C35H28O: 464.2140; found, 464.2128.
IR (KBr) mmax 1683, 1596 cm−1. Anal. calcd. for C35H28O (464.6):
C, 90.48; H, 6.07; found: C, 90.41; H, 6.09%.
(3,3-Diphenyl-indan-1-yl)-phenyl-methanone (11c)
Mp. 168–169 ◦C. 1H NMR (300 MHz, CDCl3): d 3.09 (dd, J = 6.2,
12.3 Hz, 1 H), 3.36 (dd, J = 10.3, 12.3 Hz, 1 H), 4.92 (dd, J = 6.2,
10.3 Hz, 1 H), 7.08–7.04 (m, 2 H), 7.33–7.15 (m, 12 H), 7.48 (t, J =
7.0 Hz, 2 H), 7.61–7.57 (m, 1 H), 8.02–8.00 (m, 2 H). 13C NMR
(75 MHz, CDCl3): d 47.1 (CH2), 50.0 (CH), 60.8 (Cquat), 124.9
(CH), 126.2 (CH), 126.4 (CH), 126.5 (CH), 127.2 (CH), 127.4
(CH), 128.0 (CH), 128.1 (CH), 128.5 (CH), 128.6 (CH), 128.8
(CH), 128.8 (CH), 133.3 (CH), 137.5 (Cquat), 141.7 (Cquat), 145.7
(Cquat), 147.4 (Cquat), 149.5 (Cquat), 199.8 (Cquat). EI MS (70 eV, m/z
(%)): 374 (M+, 42), 269 (M+ − C6H5CO, 100); HRMS (70 eV, EI)
calcd for C28H22O: 374.1671; found, 374.1678. IR (KBr) mmax 1680,
1596 cm−1. Anal. calcd. for C28H22O (374.5): C, 89.81; H, 5.92;
found: C, 89.57; H, 5.94%.
[2-(4-Methoxy-phenyl)-3,3-diphenyl-indan-1-yl]-phenyl-methanone
(3e)
◦
1
Mp. 205–206 C. H NMR (300 MHz, CDCl3): d 3.65 (s, 3 H),
5.26 (d, J = 11.3 Hz, 1 H), 5.52 (d, J = 11.3 Hz, 1 H), 6.35 (d, J =
8.6 Hz, 2 H), 6.51 (d, J = 8.5 Hz, 2 H), 6.69 (d, J = 8.6 Hz, 2 H),
6.80–6.77 (m, 1 H), 7.07–7.00 (m, 3 H), 7.19–7.14 (m, 3 H), 7.29–
7.25 (m, 2 H), 7.38–7.34 (m, 2 H), 7.50–7.46 (m, 2 H), 7.61–7.56
(m, 3 H), 8.02–7.99 (m, 2 H). 13C NMR (75 MHz, CDCl3): d 53.8
(CH), 55.0 (CH3), 57.8 (CH), 65.4 (Cquat), 112.9 (CH), 123.6 (CH),
126.1 (CH), 126.4 (CH), 126.5 (CH), 126.8 (CH), 127.3 (CH),
128.0 (CH), 128.3 (CH), 128.8 (CH), 128.9 (CH), 129.3 (CH),
130.1 (Cquat), 130.3 (CH), 130.7 (CH), 133.4 (CH), 138.0 (Cquat),
141.3 (Cquat), 142.0 (Cquat), 145.2 (Cquat), 149.6 (Cquat), 158.4 (Cquat),
199.2 (Cquat). EI MS (70 eV, m/z (%)): 480 (M+, 22), 375 (M+ −
C6H5CO, 100); HRMS (70 eV, EI) calcd for C35H28O2: 480.2089;
found, 480.2114. IR (KBr) mmax 1681, 1613 cm−1. Anal. calcd. for
C35H28O2 (480.6): C, 87.47; H, 5.87; found: C, 87.41; H, 5.94%.
(3,3-Diphenyl-indan-1-yl)-thiophen-2-yl-methanone (11d)
◦
1
Mp. 200–201 C. H NMR (300 MHz, CDCl3): d 3.12 (dd, J =
7.1, 12.8 Hz, 1 H), 3.38 (dd, J = 10.7, 12.8 Hz, 1 H), 4.75 (dd,
J = 7.1, 10.7 Hz, 1 H), 7.33–7.06 (m, 15 H), 7.68 (d, J = 5.1 Hz,
1 H), 7.73 (d, J = 5.1 Hz, 1 H). 13C NMR (75 MHz, CDCl3): d
47.4 (CH2), 51.6 (CH), 61.0 (Cquat), 124.8 (CH), 126.2 (CH), 126.4
(CH), 126.5 (CH), 127.3 (CH), 127.5 (CH), 128.0 (CH), 128.1
(CH), 128.3 (CH), 128.4 (CH), 128.6 (CH), 132.8 (CH), 134.4
(CH), 141.6 (Cquat), 144.8 (Cquat), 145.6 (Cquat), 147.4 (Cquat), 149.5
(Cquat), 192.7 (Cquat). EI MS (70 eV, m/z (%)): 382 (34S-M+, 3),
380 (32S-M+, 34), 269 (32S-M+ − C4H3SCO, 100); HRMS (70 eV,
EI) calcd for C26H20OS: 380.1235; found, 380.1261. IR (KBr) mmax
1659, 1653 cm−1. Anal. calcd. for C26H20OS (380.5): C, 82.07; H,
5.43; S, 8.43; found: C, 81.84; H, 5.30; S, 8.41%.
4-(3,3-Diphenyl-indane-1-carbonyl)-benzonitrile (11a)
◦
1
Mp. 157–158 C. H NMR (300 MHz, CDCl3): d 3.11 (dd, J =
6.3, 12.6 Hz, 1 H), 3.31 (dd, J = 10.2, 12.6 Hz, 1 H), 4.86 (dd,
J = 6.3, 9.9 Hz, 1 H), 7.01 (d, J = 7.5 Hz, 1 H), 7.06 (d, J =
6.9 Hz, 1 H), 7.34–7.10 (m, 12 H), 7.79 (d, J = 8.4 Hz, 2 H),
8.07 (d, J = 8.4 Hz, 2 H). 13C NMR (75 MHz, CDCl3): d 47.1
(CH2), 50.5 (CH), 60.9 (Cquat), 116.6 (Cquat), 117.8 (Cquat), 124.8
(CH), 126.4 (CH), 126.6 (CH), 126.8 (CH), 127.4 (CH), 127.7
(CH), 128.0 (CH), 128.2 (CH), 128.4 (CH), 128.5 (CH), 129.2
(CH), 132.7 (CH), 140.3 (Cquat), 140.7 (Cquat), 145.4 (Cquat), 147.0
(Cquat), 149.5 (Cquat), 198.6 (Cquat). EI MS (70 eV, m/z (%)): 399 (M+,
12), 269 (M+ − p-NCC6H4CO, 100); HRMS (70 eV, EI) calcd for
C29H21NO: 399.1628; found, 408.1631. IR (KBr) mmax 2232, 1689,
1600 cm−1. Anal. calcd. for C29H21NO (399.5): C, 87.19; H, 5.30;
N: 3.51; found: C, 87.32; H, 5.38; N, 3.47%.
(3,3-Diphenyl-indan-1-yl)-p-tolyl-methanone (11e)
◦
1
Mp. 176–178 C. H NMR (300 MHz, CDCl3): d 2.43 (s, 3 H),
3.07 (dd, J = 6.4, 12.8 Hz, 1 H), 3.37 (dd, J = 10.9, 12.8 Hz,
1 H), 4.89 (dd, J = 6.4, 10.9 Hz, 1 H), 7.08–7.04 (m, 2 H), 7.31–
7.17 (m, 14 H), 7.92 (d, J = 7.8 Hz, 1 H). 13C NMR (75 MHz,
CDCl3): d 21.7 (CH3), 47.1 (CH2), 49.9 (CH), 60.8 (Cquat), 124.9
(CH), 126.2 (CH), 126.4 (CH), 126.5 (CH), 127.1 (CH), 127.3
(CH), 128.0 (CH), 128.1 (CH), 128.5 (CH), 128.6 (CH), 129.0
(Cquat), 129.4 (CH), 129.5 (CH), 135.0 (Cquat), 141.9 (Cquat), 145.8
(Cquat), 147.5 (Cquat), 149.5 (Cquat), 199.3 (Cquat). EI MS (70 eV, m/z
(%)): 388 (M+, 20), 119 (p-H3CC6H5CO+, 100); HRMS (70 eV, EI)
calcd for C29H24O: 388.1827; found, 388.1813. IR (KBr) mmax 1674,
1604 cm−1. Anal. calcd. for C29H24O (388.5): C, 89.66; H, 6.23;
found: C, 89.49; H, 6.26%.
(4-Chloro-phenyl)-(3,3-diphenyl-indan-1-yl)-methanone (11b)
Mp. 180–181 ◦C. Anal. 1H NMR (300 MHz, CDCl3): d 3.08 (dd,
J = 6.4, 12.7 Hz, 1 H), 3.35 (dd, J = 10.2, 12.7 Hz, 1 H), 4.85
(dd, J = 6.4, 10.8 Hz, 1 H), 7.09–7.01 (m, 2 H), 7.33–7.16 (m,
12 H), 7.47 (d, J = 8.6 Hz, 2 H), 7.95 (d, J = 8.6 Hz, 2 H). 13C
NMR (75 MHz, CDCl3): d 47.1 (CH2), 50.1 (CH), 60.8 (Cquat),
124.7 (CH), 126.3 (CH), 126.5 (CH), 126.6 (CH), 127.3 (CH),
127.5 (CH), 128.2 (CH), 128.5 (CH), 128.6 (CH), 128.9 (CH),
129.1 (CH), 130.3 (CH), 135.7 (Cquat), 139.8 (Cquat), 141.3 (Cquat),
145.5 (Cquat), 147.3 (Cquat), 149.5 (Cquat), 198.5 (Cquat). EI MS (70
eV, m/z (%)): 410 (37Cl-M+, 5), 408 (35Cl-M+, 15), 269 (35Cl-M+ −
p-35ClC6H4CO, 100); HRMS (70 eV, EI) calcd for C28H2135ClO:
408.1281; found, 408.1275. IR (KBr) mmax 1682, 1588 cm−1. Anal.
calcd. for C28H21ClO (408.9): C, 82.24; H, 5.18; Cl: 8.67; found: C,
89.59; H, 5.23; Cl: 8.37%.
(3,3-Diphenyl-indan-1-yl)-(4-methoxy-phenyl)-methanone (11f)
◦
1
Mp. 153–154 C. H NMR (300 MHz, CDCl3): d 3.06 (dd, J =
7.1, 12.6 Hz, 1 H), 3.39 (dd, J = 10.3, 12.6 Hz, 1 H), 3.88 (s, 3
H), 4.88 (dd, J = 7.1, 10.2 Hz, 1 H), 6.97 (d, J = 9.1 Hz, 2 H),
7.08–7.04 (m, 2 H), 7.34–7.16 (m, 12 H), 8.01 (d, J = 8.8 Hz, 2 H).
13C NMR (75 MHz, CDCl3): d 47.1 (CH2), 49.6 (CH), 55.5 (CH3),
60.8 (Cquat), 113.9 (CH), 124.8 (CH), 126.2 (CH), 126.3 (CH), 126.5
(CH), 127.1 (CH), 127.2 (CH), 127.9 (CH), 128.1 (CH), 128.5
(CH), 128.6 (CH), 130.5 (Cquat), 131.2 (CH), 142.0 (Cquat), 145.8
(Cquat), 147.6 (Cquat), 149.5 (Cquat), 163.7 (Cquat), 198.1 (Cquat). EI
MS (70 eV, m/z (%)): 404 (M+, 22), 135 (p-H3COC6H4CO+, 100);
538 | Org. Biomol. Chem., 2008, 6, 532–539
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HRMS (70 eV, EI) calcd for C29H24O2: 404.1776; found, 404.1801.
IR (KBr) 1673, 1600 cm−1. Anal. calcd. for C29H24O2 (404.5): C,
86.11; H, 5.98; found: C, 86.00; H, 6.01%.
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(3,3-Diphenyl-indan-1-yl)-(4-hexyloxy-phenyl)-methanone (11g)
Mp. 118–119 ◦C. 1H NMR (300 MHz, CDCl3): d 0.93–0.89 (m, 3
H), 1.38–1.31 (m, 4 H), 1.50–1.45 (m, 2 H), 1.83–1.76 (m, 2 H),
3.05 (dd, J = 6.4, 12.7 Hz, 1 H), 3.39 (dd, J = 10.6, 13.4 Hz, 1
H), 4.03 (d, J = 6.4 Hz, 1 H), 4.87 (dd, J = 6.4, 10.6 Hz, 1 H),
6.95 (d, J = 8.6 Hz, 2 H), 7.08–7.03 (m, 2 H), 7.32–7.16 (m, 12
H), 8.00 (d, J = 9.1 Hz, 2 H). 13C NMR (75 MHz, CDCl3): d 14.0
(CH3), 22.6 (CH2), 25.0 (CH2), 29.0 (CH2), 31.5 (CH2), 47.1 (CH2),
49.6 (CH), 60.8 (Cquat), 68.9 (CH2), 114.4 (CH), 124.8 (CH), 126.1
(CH), 126.4 (CH), 126.5 (CH), 127.1 (CH), 127.2 (CH), 127.9
(CH), 128.1 (CH), 128.5 (CH), 128.6 (CH), 130.2 (Cquat), 131.2
(CH), 142.1 (Cquat), 145.8 (Cquat), 147.6 (Cquat), 149.5 (Cquat), 163.4
(Cquat), 198.1 (Cquat). EI MS (70 eV, m/z (%)): 474 (M+, 3), 205
(p-nhexylOC6H4CO+, 100); HRMS (70 eV, EI) calcd for C34H34O2:
474.2559; found, 474.2553. IR (KBr) mmax 1797, 1673, 1600 cm−1.
Anal. calcd. for C34H34O2 (474.7): C, 86.04; H, 7.22; found: C,
86.12; H, 7.19%.
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Acknowledgements
This work was supported by the Deutsche Forschungsgemein-
schaft (Graduate College 850), the Alexander von Humboldt
Foundation (scholarship for W.-W. L.), and the Fonds der
Chemischen Industrie. The authors also cordially thank Steffen
Wunderlich for experimental assistance and the BASF AG for the
generous donation of chemicals.
Notes and references
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