Use of (cyclopentadienone)iron tricarbonyl complexes for c-n bond formation reactions between amines and alcohols

Article abstract of DOI:10.1021/acs.joc.7b01990

The application of a series of (cyclopentadienone)iron tricarbonyl complexes to "borrowing hydrogen" reactions between amines and alcohols was completed in order to assess their catalytic activity. The electronic variation of the aromatic groups flanking the C?O of the cyclopentadienone influenced the efficiency of the reactions; however, in other cases, the Kn?lker catalyst 1, containing trimethylsilyl groups flanking the cyclopentadienone ketone, gave the best results. In some cases, the change of the ratio of amine to alcohol improves the conversion significantly. The application of iron catalysts to the synthesis of a range of amines, including unsaturated amines, was investigated.

Full text of DOI:10.1021/acs.joc.7b01990

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Article
The use of (cyclopentadienone)iron tricarbonyl complexes for
C-N bond-formation reactions between amines and alcohols
Thomas J Brown, Madeleine Cumbes, Louis J Diorazio, Guy J. Clarkson, and Martin Wills
J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.7b01990 • Publication Date (Web): 18 Sep 2017
Downloaded from http://pubs.acs.org on September 19, 2017
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The use of (cyclopentadienone)iron tricarbonyl complexes for C-N bond-formation
reactions between amines and alcohols.
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Thomas J. Brown,a Madeleine Cumbes,a Louis J. Diorazio,b Guy J. Clarksona and Martin
Willsa*
a Department of Chemistry, The University of Warwick, Coventry, CV4 7AL, UK.
b Pharmaceutical Development, AstraZeneca, Silk Road Business Park, Macclesfield,
Cheshire, SK10 2NA, UK.
* Corresponding author; m.wills@warwick.ac.uk.
Abstract.
The application of a series of (cyclopentadienone)iron tricarbonyl complexes to ‘borrowing
hydrogen’ reactions between amines and alcohols was completed in order to assess their
catalytic activity. The electronic variation of the aromatic groups flanking the C=O of the
cyclopentadienone influenced the efficiency of the reactions, however in other cases the
Knölker catalyst 1, containing trimethylsilyl groups flanking the cyclopentadienone ketone,
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gave the best results. In some cases, the change of the ratio of amine to alcohol improves the
conversion significantly. The application of iron catalysts to the synthesis of a range of
amines, including unsaturated amines, was investigated.
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Introduction.
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‘Hydrogen borrowing’ is a term commonly used to describe the use of an organometallic
catalyst to form a new CꢀN or CꢀC bond with the generation of water as the only side
product.1 In the case of CꢀN bond formation, the key steps are i) the sequential removal of
hydrogen from an alcohol to form an aldehyde or ketone through oxidation, ii) formation of
an imine via reaction with an amine, and iii) reduction of the imine to the corresponding
amine by the hydride of the catalyst used in step 1 (Scheme 1).
Scheme 1. The steps of a ‘hydrogen borrowing’ reaction.
There are many reports of the use of metalꢀbased organometallic catalysts for this application,
however the majority of examples are based on precious metals such as ruthenium, iridium
2aꢀf
etc.
although with some recent work reported on the use of lowerꢀcost metals such as
manganese.2g Ironꢀbased catalysts for organic transformations represent a desirable
alternative due to the low cost and ready availability of this element.3ꢀ11 In recent research
work, (cyclopentadienone)iron tricarbonyl complexes have been extensively applied to the
oxidation of alcohols,4 the reduction of imines5 and ketone reduction (including asymmetric
examples).6 The use of these complexes in hydrogen borrowing reactions has only been
reported recently however.5ꢀ9 The first example was in 2014 by Feringa et al.,7 using complex
1 as the precatalyst.12 Scheme 2 illustrates the reaction cycle; the active species 2 is generated
in situ through loss of a CO from the precatalyst 1 using one of a number of activation
methods. A hydride intermediate, the Knölker complex 3,13 is generated through the
oxidation step, and this provides the hydride for the reduction step.
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Scheme 2. The steps of a ‘hydrogen borrowing’ reaction using an iron cyclopentadienone
tricarbonyl catalyst, first reported by Feringa et al.7
In our own studies we previously reported the use of iron catalyst 4 in the synthesis of a range
of secondary amines via borrowing hydrogen methodology from aryl amines and primary
alcohols, although our best results were obtained from the reactions of benzyl alcohols with
aromatic amines (Scheme 3).8
Scheme 3. Use of a tetraphenylꢀsubstituted complex 4 for CꢀN bond formation between a
benzyl alcohol and aniline.
Zhao et al. published a modification to the methodology whereby the addition of a Lewis acid
to increase the reactivity of the imine assisted the imine reduction step to form the desired
final amine product in reactions with secondary alcohols (Scheme 4).9
Scheme 4. Secondary alcohols as substrates by Zhao et al.
We have continued to work on an extended range of iron complexes for hydrogen borrowing
applications, and on extending the scope of the catalysts, and our recent detailed results from
this study are described below.
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Results and discussion.
To date, the iron cyclopentadienone complexes used in CꢀN bond formation include the
tetraphenylꢀsubstituted 4 and the complex 1, and close derivatives of these.5ꢀ10 Complexes
analogous to 1, but containing aromatic rings flanking the central C=O benefit from ease of
preparation,14 and offer an opportunity to investigated the effect of changes to the electronꢀ
rich or ꢀpoor nature of the substituent groups on their reactivity. Hence iron complexes 5ꢀ9
and 16, each based on the cyclohexyl backbone, were targeted for preparation via an
intramolecular Fe(CO)5ꢀcatalysed cyclisation of dialkyne precursors 10ꢀ15.14
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Scheme 5. Synthesis of arylꢀsubstituted iron(cyclopentadienone) catalysts.
The synthesis of iron complexes 5-8 was achieved starting from the respective diaryl
dialkyne precursors 10ꢀ13, themselves synthesised via a Sonogashira reaction15 (Scheme 5),
except for 12, which was more challenging and required an alternative set of conditions to
yield intermediate 12, but with a yield of only 12%. The synthesis of iron complexes using
the intramolecular cyclisation approach was successful for compounds 5ꢀ8, giving products in
yields of 91ꢀ98% (Scheme 5).14 The synthesis of iron complex 9 was unsuccessful and the
reaction resulted in the complete decomposition of the starting material. However the
electronꢀdeficient iron bisꢀtrifluoromethylphenyl complex 16 was prepared in a yield of 97%
from the dialkyne precursor 15. Crystals of complex 6 suitable for analysis by Xꢀray
diffraction were grown by slow evaporation from EtOAc (Figure 1, full details in Supporting
information, Table S1). An interesting aspect of the structure is the twisted nature of the
aromatic rings flanking the C=O bond of the cyclopentadienyl group, creating a ‘propellerꢀ
type’ arrangement.6
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Figure 1: Single crystal Xꢀray structure of 6. Hydrogens omitted for clarity and ellipsoids
drawn at 50% probability.
Before testing all of the catalysts, we screened a number of solvents in the reaction between
aniline 17 and benzyl alcohol 18 to give amine 19 (Scheme 6) using catalyst 5 for initial tests.
Activation of the catalyst was achieved using trimethylamine oxide.14b,16 Of the solvents
tested, good results were obtained using xylene, toluene, tetrahydrofuran and ethyl acetate,
which all gave conversions of >85% with the best conversion of 90% being observed with
xylene. The use of cyclopentylmethyl ether was also examined as this solvent had been
previously used with success by Feringa,7 but only a 70% conversion was observed in our
study. A poorer result was obtained with the use of diethyl ether with a conversion of 60%
and the use of dichloromethane resulted in the formation of an insoluble solid with no
conversion to the desired product. However this solid was not characterised.
Ph
O
Ph
Solvent / % Conversion
Fe cat.
(10 mol%)
Fe
Xylene 90%
Toluene 87%
DCM 0%
OC
OC
CO
NH2
H
N
HO
THF 85%
+
Me3NO (9 mol%)
Solvent
CyOMe 70%
EtOAc 85%
Et2O 66%
18
17
19
140 o
C
Scheme 6. Solvent screening in CꢀN bond formation.
With a screening of possible solvents complete, xylene was selected for use in further
‘hydrogen borrowing’ reactions with iron complexes 6ꢀ8 and 10 to compare their potential
for the catalysis of the reaction of amine 17 with a range of primary alcohols to give products
19ꢀ24 (Table 1). Conversions were recorded in all cases and isolated yields were obtained
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where stated. For the reaction with benzaldehyde, the highest conversions were achieved
using the more electronꢀrich and electronꢀpoor iron complexes analogues, 7 and 10, which
gave conversions of 91% and 87% respectively. Iron complexes 6 and 8 gave lower
conversions of 60% and 66% respectively. This pattern was not consistent throughout the
substrates however; catalyst 7 generally gave lower conversions, whilst the phenyl catalyst 5
and the bis pꢀmethyoxyphenyl catalyst 6 performed well for most substrates. Some
combinations were quite specific; for example catalyst 10 was the best for the reaction with
4ꢀphenylbutanol, whilst 5 and 6 were significantly better than the other catalysts for the
conversion of 2ꢀ(4ꢀmethoxyphenyl)ethanol.
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Table 1. Results of CꢀN bond formation via ‘hydrogen borrowing’ reactions.
5 H
6 OMe
7 OMe3 8 Cl
16 CF3
Catalyst:
Product
Conv (c) and yield (y) of amine / %
100 (c)
90 (y)
60 (c)
95 (c)
91 (c)
66 (c)
87 (c)
19
90 (c)
65 (y)
>95 (c) 55 (c)
100 (c)
92 (y)
20
100 (c)
96 (y)
>95 (c)
95 (y)
50 (c)
30 (c)
100 (c)
89 (y)
55 (c)
21
>90 (c)
80 (y)
70 (c)
72 (c)
100 (c)
82 (y)
22
23
40 (c)
100 (c)
100 (c) nd
100 (c)
94 (y)
100 (c)
92 (y)
100 (c)
96 (y)
60 (c)
40 (c)
60 (c)
24
Nd = not determined.
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3ꢀ(4ꢀMethoxyphenyl)ꢀ1ꢀpropanol also reacted in high yield with substituted anilines using the
bis(methoxyphenyl)ꢀsubstituted complex 6 to give products 25 and 26 (Scheme 7). Nꢀ
methylaniline gave a tertiary amine product 27 in 50% yield using the same catalyst. Under
the conditions used, which required an excess of amine in line with our earlier
communication,8 more basic nonꢀaromatic amines such as benzylamine, pyrrolidine, and 4ꢀ
phenylbutylamine failed to give products, possibly due to catalyst inhibition.17
Diphenylamine also failed to react under the conditions attempted.
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Scheme 7. Variation of the aniline derivative in ‘hydrogen borrowing’ reactions using
bis(methoxyphenyl) iron complex 6.
A complex pattern of results emerged from the reactions of aniline with cyclic alcohols and
diols using the bis(aryl)ꢀsubstituted catalysts (Figure 2). Aliphatic secondary cyclic alcohols
cyclopentanol, cyclohexanol, cycloheptanol and
representing a valuable application of the methodology. However cyclic or acyclic
benzylic/propargylic alcohols including as ꢀtetralol, 1ꢀphenylethanol and 2ꢀhydroxyꢀ4ꢀ
βꢀtetralol gave products in good yields,
α
phenylꢀbutꢀ3ꢀyne did not give the products of hydrogen borrowing (Figure 2). It is possible
that these alcohols form a stable imine or possibly the enamine upon condensation of the
corresponding ketone with aniline, but these intermediates were not isolated from the
reactions. The reaction of aniline with diols was also briefly assessed, and products were
isolated from the reactions, but in low yields and in the case of 1,5ꢀdihydroxypentane, a
product could not be isolated (Figure 2). In the diol reactions, some aminoalcohol was also
formed in each case, i.e. from the reaction of only one alcohol in the diol.
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Figure 2. Products formed from the reaction of aniline with cyclic alcohols (2:1
o
aniline:alcohol), cyclic alcohols which did not work (10% catalyst, 2:1, 140 C, 16h), and
products of reactions with diols (2 eq. diol employed).
The reactions of amines with alcohols containing an unsaturated functionality more distant
from the alcohol are capable of forming valuable addition products (Figure 3). Initially we
used our standard conditions i.e. an excess of amine, which had previously given good
results. Unfortunately, for these substrates the yields were low using the bis(aryl) complexes
5 and 6 as catalysts. In contrast, improved results were achieved using the Knölker catalyst
o
precursor 1 (Figure 3A). At 140 C, both alkene and alkyneꢀcontaining products 37 and 38
were formed in 95% and 80% isolated yields respectively, and 37 was also formed in 75%
o
yield at 120 C. Successful additions of the pentenyl group were also achieved using pꢀ
methoxy and pꢀchloro anilines to give 39 and 40 respectively (Figure 3A). As far as we are
aware, these represent the first reported examples of CꢀN bond formation under hydrogen
borrowing conditions of unsaturated alcohols using an ironꢀbased catalyst. Under these
conditions, however, the reaction of the corresponding nonꢀTMSꢀprotected alkyne hexꢀ5ꢀynꢀ
1ꢀol did not yield a product, possibly due to an interaction with the terminal alkyne causing
catalyst inhibition.
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H
N
H
N
A
NH2
Bis TMS 1
+
R
TMS
10% Me3NO
xylenes, 140 o
HO
C
38 80%
(120 oC; 38%)
37 95%
(120 oC; 75%)
2 : 1
8
9
X=Cl or OMe
NH2
H
N
H
N
Bis TMS 1
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R
+
10% Me3NO
HO
MeO
X
xylenes, 140 o
C
40 42%
Cl
39 70%
2 : 1
B
H
N
H
N
Bis TMS 1
TMS
OMe
NH2
41 90%
42 20%
R
+
10% Me3NO
xylenes, 140 o
HO
C
H
N
H
N
1 : 2
44 51%
43 52%
Figure 3. Products of reaction of aliphatic and unsaturated alcohols to A) anilines and B)
benzylamine using catalyst 1. For best results in A), an excess of the aniline is required, for
B) and excess of alcohol gives the best results.
In an extension of this work, we thought it was possible that more basic (i.e. nonꢀaromatic)
amines could be inhibiting the iron catalyst, therefore we reversed the ratio of reagents so that
an excess of alcohol was used. This resulted in the successful formation of the desired amine
products from the reaction of benzylamine with pentanol (Figure 3B) and products 41-44
containing alkene, alkyne and aromatic functionality were successfully added to the amine.
To expand upon this improved reactivity, the amine:alcohol 1:2 ratio was applied to the
hydrogen borrowing reactions of the cyclic basic amine 4ꢀphenylpypiperidine and in the
coupling products 45-53 were formed in good yields from primary and secondary alcohols
(Figure 4). 4ꢀPhenylpiperidine, possibly due to its more hydrophobic nature and better
solubility in xylene, was found to be more compatible with this application, under the
reaction conditions used, than more hydrophilic amines such as piperidine and morpholine,
from which products were not isolated.
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Figure 4. Products formed from the reaction of 4ꢀphenylpiperidine and alcohols using
catalyst 1 and a 1:2 ratio of amine:alcohol (140 oC, xylene, 16h).
The revised reaction conditions, coupled to the use of catalyst 1, permitted further CꢀN bond
formation reactions with a benzylic amine (Figure 5). In these examples, 3ꢀtrifluoromethyl
benzylamine was selected as a representative substituted benzylic amine as this had been
reported to give good results in a previous study.7 We were able to successfully generate a
range of addition products 54-63 in good yields, including products from reactions with
cyclic alcohols, an acyclic secondary alcohol and diols. In one further example, a longer
chain amine, 4ꢀphenylbutylamine, was successfully coupled with benzyl alcohol to form the
secondary amine 64.
Figure 5. Products of reaction of 3ꢀtrifluoromethylbenzyl alcohol with a range of alcohols
and diols, using catalyst 1 and a 1:2 ratio of amine:alcohol.
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We also found that tertiary amines 65-68 could be formed from secondary ones using the
modified conditions, including the alkylation of N-methylꢀN-cyclohexylamine, as illustrated
in Figure 6.
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Figure 6. Products formed from the reaction of secondary amines with primary alcohols
using catalyst 1 and a 1:2 ratio of amine:alcohol. The arrow indicates the position of the
newlyꢀformed bond.
A class of alcohol substrate which continues to be challenging in this application is that
containing oxygen atoms at a nearby position to the alcohol (Figure 7). The reasons for this
are not immediately clear, although it is possible that the substrate or an intermediate in the
reaction inhibits the catalyst by chelation. Studies are ongoing in order to establish a better
understanding of this reaction and a potential solution.
Figure 7. Oxygenꢀcontaining alcohols which did not work in this application.
Conclusion.
A series of novel iron complexes, containing aryl groups flanking the central C=O in the
cyclopentadienyl ring, were prepared and applied to the catalysis of the formation of CꢀN
bond formation of aromatic amines via hydrogen borrowing. For alcohols containing double
or triple bonds, the Knölker catalyst 1 was more effective however, and gave unsaturated
products in good yields using anilines as the amine component. For coupling reactions
involving basic amines, the reversed 1:2 ratio of amine:alcohol gave improved results,
possibly due to reduced inhibition of the catalyst.
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Experimental section.
General Experimental Methods
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All solvents and reagents were degassed before use and all reactions were carried out under
either a nitrogen atmosphere. Reactions were monitored by TLC using aluminium backed
silica gel 60 (F254) plates, visualized using UV 254 nm and phosphomolybdic acid or
potassium permanganate dips as appropriate. Flash column chromatography was carried out
routinely on silica gel. Reagents were used as received from commercial sources unless
otherwise stated. Dry solvents were purchased and used as received. All synthesis of iron
complexes and iron catalytic reaction were carried out in ACE 15 Ml 150 psi pressure tested
pressure tubes and heated in aluminium heating blocks. 1H NMR spectra were recorded on a
Bruker DPX (400 or 500 MHz) spectrometer. Chemical shifts are reported in δ units, parts
per million relative to the singlet at 7.26 ppm for chloroform and 0.00 ppm for TMS. Mass
spectra for analysis of synthetic products were recorded on a Bruker Esquire2000 or a Bruker
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MicroTOF mass spectrometer. Coupling constants (J) are measured in Hertz. IR spectra were
recorded on a PerkinꢀElmer Spectrum One FTꢀIR Golden Gate. Melting points were recorded
on a Stuart Scientific SMP 1 instrument and are uncorrected.
General Procedure for Aniline Related ‘Hydrogen Borrowing’ Reactions. Tricarbonyl(1,3ꢀ
diphenylꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (43.0 mg, 0.100 mmol, 0.1 equiv.) 5 was
placed in a thoroughly dried 15 mL pressure tube with a stirrer bar and xylene (0.5 mL) was
added. Distilled aniline (137 µL, 139 mg, 1.5 equiv.) and alcohol (1.00 mmol, 1 equiv.) were
added with stirring. The pressure tube was sealed with a septum and degassed through a
nitrogen bubbler for 15 minutes. Trimethylamine Nꢀoxide (7.00 mg, 0.09 mmol, 0.09 equiv.)
was then added with stirring and the solution was further degassed for 5 minutes before being
sealed with a pressure tube lid and stirred at 140 oC for 16 hours. The tube was then allowed
to cool to room temperature and its contents were passed through celite with ethyl acetate.
Solvent removal via a rotary evaporator gave the product as a dark brown residue, which was
purified as indicated in each case.
General procedure for Sonogashira Reactions. In a dried and degassed 100 mL roundꢀbottom
flask, 1,7ꢀoctadiyne (1.00g, 9.42 mmol, 1.0 equiv.) and aryl iodide (20.7 mmol, 2.2 equivs.)
were dissolved in anhydrous THF (34 mL) with stirring. PdCl2(PPh3)2 (50.0 mg, 0.0712
mmol, 0.03 equiv.) and CuI (27.0 mg, 0.142 mmol, 0.06 equiv.) were added to the stirred
i
solution to give a yellow suspension. Pr2NH (13.2 mL, 9.53 g, 10 equiv.) were added and a
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thick precipitate formed. Vigorous stirring overnight was followed by filtration through celite
with ethyl acetate. This served to remove precipitates and metal impurities, and gave the
product as a brown residue after solvent removal via a rotary evaporator. The products were
purified as indicated.
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1,8-Diphenylocta-1,7-diyne 10 15b
1,7ꢀOctadiyne (1.00 g, 9.42 mmol) was added to a stirred
.
solution of iodobenzene (4.23 g, 20.7 mmol) in dry THF (34 mL, PdCl2(PPh3)2 (50.0 mg,
i
0.071 mmol), CuI (27.0 mg, 0.141 mmol) and Pr2NH (9.53 g, 94.2 mmol) were added and
reaction was stirred at room temperature overnight. The reaction solidified and was therefore
passed through a celite/silica plug with 20% ethyl acetate/ pentane to give a brown oil after
solvent removal under reduced pressure. Recrystallisation from methanol gave the product as
a white solid (2.19 g, 8.49 mmol, 90.1 %). 1H NMR (400 MHz, CDCl3)
Hz, Ar ), 7.25ꢀ7.29 (6H, m, Ar ), 2.48 (4H, br. s., CH2CH2CH2CH2), 1.79 (4H, br. s.,
CH2CH2CH2CH2) ppm.
δ 7.40 (4 H, d, J=4.0
H
H
Tricarbonyl(1,3-diphenyl-4,5,6,7-tetrahydro-2H-inden-2-one)iron 5 14b
.
1,8ꢀDiphenyloctaꢀ
1,7ꢀdiyne (0.500 g, 1.94 mmol) was placed in a dried pressure tube with a stirrer bar with dry
toluene (5.00 mL), and Fe(CO)5 (786 µL, 1.14 g, 5.82 mmol) was added. The reaction
solution was degassed thoroughly with N2 for 15 minutes. The tube was sealed and heated to
o
130 C overnight. The tube was then allowed to cool to room temperature and tube contents
were passed through a silica plug with 50:50 EtOAc: pentane. The solvent was then removed
under reduced pressure to give 5 as a brown solid (0.729g, 1.71 mmol, 87.9%). Mp 164ꢀ165
oC, lit. Mp 165ꢀ166 oC; νmax 3062, 2950, 2864, 1641, 1627 cmꢀ1; 1H NMR (500 MHz, CDCl3)
δ 7.74 (4H, d,
J
=7.2 Hz, ArH), 7.26 ꢀ 7.47 (6H, m, ArH), 2.64 ꢀ 2.89 (4H, m, CH2), 1.94
(4H, br. s., CH2) ppm; 13C NMR (126 MHz, CDCl3)
δ
209.0, 169.5, 22.3, 131.3, 129.7,
128.4, 127.9, 100.4, 81.9, 23.7 ppm; m/z (ESI) 427 (M+H)+, 449 (M+Na)+.
1,8-Bis(4-methoxyphenyl)octa-1,7-diyne 11. 1,8ꢀBis(4ꢀmethoxyphenyl)octaꢀ1,7ꢀdiyne was
prepared via the same method as 1,8ꢀdiphenyloctaꢀ1,7ꢀdiyne with 1,7ꢀoctadiyne (750mg, 7.07
mmol), 4ꢀiodoanisole (3.31g, 14.1 mmol,), PdCl2(PPh3)2 (74.0 mg, 0.106mmol), CuI
(40.0mg, 0.212 mmol) and iPr2NH (7.15 g, 70.6 mmol) to give 1,8ꢀbis(4ꢀ
o
methoxyphenyl)octaꢀ1,7ꢀdiyne as a white solid(1.77g, 5.56 mmol, 78.7%). Mp 39ꢀ40 C;
(ESI) (M+H)+ Found, C22H23O2 requires 319.1693; HRMS (ESIꢀTOF) m/z: [M + H]+ Calcd
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for C22H23O2 319.1693; Found 319.1694; νmax 2998, 2937, 1605, 1568 cmꢀ1; H NMR (500
MHz, CDCl3) 7.33 (4 H, d, J=8.8 Hz, Ar ), 6.81 (4 H, d, J=8.8 Hz, Ar ), 3.79 (6 H, s,
CH3), 2.34ꢀ2.37 (4 H, m, CH2CH2CH2CH2), 1.73ꢀ1.77 (4 H, m, CH2CH2CH2CH2) ppm;
13C NMR (126 MHz, CDCl3)
m/z ESI 319 (M+H)+.
δ
H
H
O
δ 159.0, 132.9, 116.9, 113.8, 88.2, 80.6, 55.3, 28.0, 19.0 ppm;
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Tricarbonyl(1,3-di(4-methoxyphenyl)-4,5,6,7-tetrahydro-2H-inden-2-one)iron
6.
Tricarbonyl(1,3ꢀdi(4ꢀmethoxyphenyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron was prepared
via the same procedure as was used for tricarbonyl(1,3ꢀdiphenylꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀ
indenꢀ2ꢀone)iron. In an oven dried pressure tube, 1,8ꢀbis(4ꢀmethoxyphenyl)octaꢀ1,7ꢀdiyne
(500 mg, 1.57 mmol) was placed in dry toluene (5.00 mL) with Fe(CO)5 (637 µl, 4.72 mmol)
and the solution was vigorously degassed with a N2 line for 15 minutes. The tube was then
o
sealed and heated with stirring to 130 C overnight. Complex 6 was isolated as brown solid
o
(726 mg, 1.49 mmol, 94.8%). Mp 166ꢀ167 C; HRMS (ESIꢀTOF) m/z: [M + H]+ Calcd for
1
C26H23FeO6 487.0839; Found 487.0842; νmax 2941, 2054, 1618 cmꢀ1; H NMR (500 MHz,
CDCl3)
δ
7.73 (4 H, d,
J
=10.0 Hz, Ar
H
), 6.91 (4 H, d,
J
=10.0 Hz,Ar
H
), 3.82 (6 H, s, OCH3),
2.84ꢀ2.82 (4 H, m, CH2), 1.92 (4 H, br. s., CH2) ppm; 13C NMR (126 MHz, CDCl3)
169.3, 159.1, 130.8, 121.9, 113.9, 99.70, 81.9, 55.3, 23.9, 22.3 ppm; m/z 487 (M+H)+, 509
(M+Na)+.
δ
209.3,
1,8-Bis(3,4,5-trimethoxybenzene)octa-1,7-diyne 12. In a dried and degassed (N2) 100 mL
roundꢀbottomed flask equipped with a Findenser, 1,7ꢀoctadiyne (1.00 g, 9.42 mmol) and 5ꢀ
bromoꢀ1,2,3ꢀtrimethoxybenzene (5.121 g, 20.7 mmol) were placed in triethylamine (25 mL)
with stirring via magnetic stirrer bar. PdCl2(PPh3)2 (100 mg, 0.142 mmol) and CuI (26 mg,
o
0.137 mmol) were added and the reaction was stirred at 50 C for two days. The reaction
mixture was purified via column chromatography eluted with 0ꢀ50% ethyl acetate in pentane
o
to give the product as a white crystalline solid (0.507 g, 1.16 mmol, 12.3%). Mp 51ꢀ52 C;
ν
max 2956, 2918, 1621 cmꢀ1; 1H NMR (400 MHz, CDCl3)
ArOMe), 2.45ꢀ2.49 (4 H, m, CH2CH2CH2CH2), 1.77ꢀ1.81 (4 H, m, CH2CH2CH2CH2) ppm;
δ 6.64 (4 H, s, ArH), 3.84 (18 H, s,
13C NMR (101 MHz, CDCl3)
v; m/z 461 (M+H)+.
δ
153.0, 138.2, 119.0, 108.6, 88.9, 80.9, 60.9, 56.1, 27.9, 19.0
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Tricarbonyl(1,3-di(3,4,5-trimethoxyphenyl)-4,5,6,7-tetrahydro-2H-inden-2-one)iron
7.
Tricarbonyl(1,3ꢀdi(3,4,5ꢀtrimethoxyphenyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron
was
6
7
8
9
synthesised via the same procedure as was used for tricarbonyl(1,3ꢀdiphenylꢀ4,5,6,7ꢀ
tetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron, using 1,8ꢀbis(3,4,5ꢀtrimethoxybenzene)octaꢀ1,7ꢀdiyne
(0.400 g, 0.913 mmol) and Fe(CO)5 (537 µL, 800 mg, 2.74 mmol) in toluene (5 mL) to give 7
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60
o
as a yellow solid (0.454 mg, 0.897 mmol, 98.2%). Mp 167ꢀ168 C; HRMS (ESIꢀTOF) m/z:
[M + Na]+ Calcd for C30H30FeNaO10 629.1081; Found 629.1079; νmax 2941, 2837, 1619 cmꢀ1;
1H NMR (500 MHz, CDCl3)
CH2), 2.69 ꢀ 2.79 (2 H, m, CH2), 1.94ꢀ1.92 (4 H, m, CH2) ppm; 13C NMR (126 MHz, CDCl3)
209.2, 169.6, 152.9, 137.9, 126.6, 107.0, 99.9, 82.1, 60.8, 56.1, 23.9, 22.3 ppm; m/z 629
δ 7.03 (4 H, s, ArH) 3.88 (18H, s, ArOMe), 2.82 ꢀ 2.91 (2 H, m,
δ
(M+Na)+.
1,8-(4-Chlorophenyl)octa-1,7-diyne 13. 1,8ꢀ(4ꢀChlorophenyl)octaꢀ1,7ꢀdiyne was synthesised
through the same method as for the synthesis of 1,8ꢀdiphenyloctaꢀ1,7ꢀdiyne, using 1,7ꢀ
octadiyne (0.300 g, 2.83 mmol) and 1ꢀchloroꢀ4ꢀiodobenzene (1.49g, 6.23 mmol),
i
PdCl2(PPh3)2 (30.0 mg, 0.0425 mmol), CuI (16.0 mg, 0.0850 mmol) and Pr2NH (3.97 mL,
2.86 g, 28.3 mmol). The reaction was performed at room temperature overnight and the
reaction mixture was passed through a celite silica plug with 20:80 ethyl acetate:pentane.
Subsequent column chromatography eluted with 0ꢀ20% ethyl acetate in pentane gave the
product as a white solid (0.759 g, 2.32 mmol, 82.2%). Mp 42ꢀ43 oC; HRMS (ESIꢀTOF) m/z:
[M + Ag]+ Calcd for C20H16AgCl2 434.9668; Found 434.9655; νmax 2942, 2871, 2769, 1624
cmꢀ1; 1H NMR (500 MHz, CDCl3)
Ar
), 2.46ꢀ2.42 (4H, m, CH2CH2CCAr), 1.75 (4H, m, CH2CH2CH2CH2) ppm; 13C NMR
δ 7.30 (4H, d, J= 10.0 Hz, ArH), 7.23 (4H, d, J= 10.0 Hz,
H
(126 MHz, CDCl3)
(M+Ag)+.
δ 134.6, 133.1, 128.6, 122.5, 90.9, 80.0, 27.8, 19.1 ppm; m/z ESI 435
Tricarbonyl(1,3-di(4-chloro)phenyl-4,5,6,7-tetrahydro-2H-inden-2-one)iron
8.
Tricarbonyl(1,3ꢀdi(4ꢀchloro)phenylꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron was prepared via
the same method used previously to prepare tricarbonyl(1,3ꢀdiphenylꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀ
indenꢀ2ꢀone)iron, using 1,8ꢀbis(4ꢀchlorophenyl)octaꢀ1,7ꢀdiyne (0.500g, 1.53 mmol) and
o
Fe(CO)5 (620 µL, 4.59 mmol) in dry toluene (5.00 mL) at 130 C overnight to 8 as a brown
o
solid (0.708g, 1.43 mmol, 93.8%). Mp 152ꢀ153 C; HRMS (ESIꢀTOF) m/z: [M + H]+ Calcd
for C24H17Cl2FeO 494.9848; Found 494.9855; νmax 2062, 2013, 1625, 1606 cmꢀ1; H NMR
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(500 MHz, CDCl3)
δ
7.74 (4 H, d, ArH), 7.38 (4 H, d, ArH), 2.37 ꢀ 3.04 (4 H, m,
13
CH2CH2CH2CH2),1.96 (4 H, br. s., CH2CH2CH2CH2) ppm; C NMR (126 MHz, CDCl3)
δ
214.6, 208.6, 169.0, 133.9, 130.8, 129.9, 128.7, 100.2, 80.3, 23.8, 22.2 ppm; m/z ESI 495
(M+H)+.
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1,8-Bis(4-nitrophenyl)octa-1,7-diyne
14.
1,8ꢀBis(4ꢀnitrophenyl)octaꢀ1,7ꢀdiyne
was
synthesised through the same procedure as used previously for 1,8ꢀdiphenyloctaꢀ1,7ꢀdiyne,
using 1,7ꢀoctadiyne (300 mg, 2.83 mmol) and 1ꢀiodoꢀ4ꢀnitrobenzene (1.551 g, 6.23 mmol),
i
PdCl2(PPh3)2 (50.0 mg, 0.0707 mmol), CuI (27.0 mg, 0.141 mmol) and Pr2NH (6.60 mL,
4.77 g, 47.1 mmol) to give 1,8ꢀbis(4ꢀnitrophenyl)octaꢀ1,7ꢀdiyne as an orange solid (0.339 g,
o
0.974 mmol, 34.4%). Mp 40ꢀ42 C; HRMS (ESIꢀTOF) m/z: [M + Na]+ Calcd for
C20H16N2NaO4 371.1002; Found 371.1001; νmax 2931, 1590 cmꢀ1; H NMR (400 MHz,
1
CDCl3)
δ 8.16 (4 H, d, J=8.0 Hz, ArH), 7.52 (4 H, d, J=8.0 Hz, ArH), 2.54 (4 H, br. s.,
CH2CH2CH2CH2), 1.82 (4 H, br. s., CH2CH2CH2CH2) ppm; 13C NMR (101 MHz, CDCl3)
146.7, 132.3, 130.7, 123.5, 95.8, 79.8, 27.6, 19.2 ppm; m/z ESI 349 (M+H)+.
δ
1,8-Bis(4-(trifluoromethyl)phenyl)octa-1,7-diyne 15. 1,8ꢀBis(4ꢀ(trifluoromethyl)phenyl)octaꢀ
1,7ꢀdiyne was synthesised through the same procedure as previously used to synthesise 1,8ꢀ
diphenyloctaꢀ1,7ꢀdiyne, with 1,7ꢀoctadiyne (375 μL, 300 mg, 2.83 mmol), 4ꢀ
iodobenzotrifluoride (916 µL, 1.70 g 6.23 mmol), PdCl2(PPh3)2 (30.0 mg, 0.0425 mmol), CuI
i
(16.0 mg, 0.0850 mmol) and Pr2NH (3.97 mL, 2.86 g, 28.3 mmol) to give 1,8ꢀbis(4ꢀ
(trifluoromethyl)phenyl)octaꢀ1,7ꢀdiyne as a white solid after column chromatography eluted
with 0ꢀ20% ethyl acetate in hexane (0.780 g, 1.98 mmol, 69.6%). Mp 35ꢀ36 oC; HRMS (ESIꢀ
TOF) m/z: [M + Ag]+ Calcd for C22H16AgF6 501.0202; Found 501.0212; νmax 2073, 2023,
1
1995 cmꢀ1; H NMR (500 MHz, CDCl3)
δ
7.51 ꢀ 7.59 (4H, d,
) 2.13 ꢀ 2.80 (4 H, m, CH2CH2CH2CH2) 1.59 ꢀ 1.95 (4 H, m,
CH2CH2CH2CH2) ppm; 13C NMR (126 MHz, CDCl3)
131.8, 129.4, 127.8 (J = 32 Hz),
J= 8.0 Hz, ArH) 7.43 ꢀ 7.51 (4
H, d, J= 8.0 Hz, ArH
δ
125.2, 123.7 (J = 230 Hz), 92.5, 79.9, 27.7, 19.0 ppm; m/z (ESI) 501 (M+Ag, 100%).
Tricarbonyl(1,3-di(4-trifluoromethylphenyl)-4,5,6,7-tetrahydro-2H-inden-2-one)iron
16.
Tricarbonyl(1,3ꢀdi(4ꢀtrifluoromethylphenyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron
was
synthesised via the procedure previously used to prepare tricarbonyl(1,3ꢀdiphenylꢀ4,5,6,7ꢀ
tetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron, using 1,8ꢀbis(4ꢀ(trifluoromethyl)phenyl)octaꢀ1,7ꢀdiyne (500
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mg, 1.27 mmol) and Fe(CO)5 (513 µl, 3.81 mmol) in toluene (5 mL) to give 10 as a brown
o
solid (690 mg, 1.23 mmol, 97%). Mp 155ꢀ156 C; HRMS (ESIꢀTOF) m/z: [M + Na]+ Calcd
1
for C26H16F6FeNaO4 585.0195; Found 585.0196; νmax 2943, 2070, 1640 cmꢀ1; H NMR (500
6
7
8
9
MHz, CDCl3)
δ
7.93 (4H, m,
J
= 10.0 Hz, Ar
H
), 7.64ꢀ7.60 (4H, m,
J
= 10.0 Hz, Ar
H), 2.79
13
(4H, m, C 2), 1.98 (4H, m, C
H
H
2) ppm; C NMR (126 MHz, CDCl3)
δ
207.5, 168.6, 135.9,
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129.6, 129.8 (J= 32 Hz), 125.6, 125.2 (J = 230 Hz), 101.7, 79.4, 23.0, 21.6 ppm; m/z (ESI)
585 (M+Na)+.
1,8-Bis(trimethylsilyl)octa-1,7-diyne 12a
In a dried and degassed 250 mL roundꢀbottom flask,
.
under N2, Zn(OTf)2 (335 mg, 0.922 mmol) and NEt3 (7.70 mL, 5.59 g, 55.3 mmol) were
dissolved in anhydrous DCM (50.0 mL) and the solution was cooled to 0 oC in an ice bath. A
solution of 1,7ꢀoctadiyne (2.44 mL, 1.96 g, 18.4 mmol) in anhydrous DCM (15.0 mL) was
slowly added under N2 followed by a solution of TMSOTf (10.0 mL, 12.3 g, 55.3 mmol) in
anhydrous DCM (15.0 mL), also slowly added under N2 with the iceꢀbath remaining in place.
Heavy white fumes were produced, which dispersed to give a red/brown solution. The
reaction was stirred overnight at room temperature, quenched with NH4Cl and extracted with
Et2O (3x 50 mL). The organic fraction was dried with anhydrous Na2SO4, filtered and the
solvent removed via a rotary evaporator to give a brown oil. 1,8ꢀBis(trimethylsilyl)octaꢀ1,7ꢀ
diyne was isolated through column chromatography on silica gel eluted with pentane to give
the product as a clear solid (3.35 g, 13.3 mmol, 72.7%). 1H NMR (300 MHz, CDCl3)
2.32 (4 H, m, C 2CH2CH2C 2), 1.57 ꢀ 1.68 (4 H, m, CH2C 2C 2CH2), 0.15 (18 H, s,
Si(C 3)3) ppm.
δ 2.20 ꢀ
H
H
H
H
H
Tricarbonyl(1,3-di(trimethylsilyl)-4,5,6,7-tetrahydro-2H-inden-2-one)iron
1 13,14b
.
Tricarbonyl(1,8ꢀbis(trimethylsilyl)octaꢀ1,7ꢀdiyne was synthesised through the general
procedure as was used for tricarbonyl(1,3ꢀdiphenylꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron,
using 1,8ꢀbis(trimethylsilyl)octaꢀ1,7ꢀdiyne (500 mg, 2.00 mmol) and Fe(CO)5 (792 µL ,
1.18g, 6.00 mmol) in toluene (5 mL). Tricarbonyl(1,3ꢀdi(trimethylsilyl)ꢀ4,5,6,7ꢀtetrahydroꢀ
2Hꢀindenꢀ2ꢀone)iron was isolated through column chromatography eluted with ethyl acetate
0ꢀ5% in pentane to give the product as a yellow solid (610 mg, 1.46 mmol, 73.0%). 1H NMR
(500 MHz, CDCl3)
δ
2.54ꢀ2.58 (4 H, m, C
H2CH2CH2CH2), 1.80ꢀ1.85 (4 H, m,
13
CH2C 2C 2CH2), 0.28 (18 H, br. s., Si(C
H
H
H
3)3) ppm; C NMR (126 MHz, CDCl3)
δ
209.0,
181.2, 111.0, 71.7 , 24.8, 22.4, ꢀ0.3 ppm; m/z 419 (M+H, 100%).
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N-Benzylaniline 19 8
.
N
ꢀBenzylaniline was synthesised via the same procedure as previously
6
7
8
9
described with benzyl alcohol (110 µL, 108 mg, 1.00 mmol), aniline (182 µL, 186 mg, 2.00
mmol), tricarbonyl(1,3ꢀdi(phenyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (42.6 mg, 0.100
mmol) and trimethylamine Nꢀoxide (6.75 mg, 0.09 mmol). Column chromatography, eluted
with 0ꢀ5% ethyl acetate in pentane, gave the product as a colourless oil (165 mg, 0.90 mmol,
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52
53
54
55
56
57
58
59
60
90.0%). 1H NMR (400 MHz, CDCl3)
δ
7.25 ꢀ 7.40 (5 H, m, Ar
), 6.60ꢀ6.55 (2 H, m, =8.0 Hz, Ar ), 4.26 (2 H, s, C
148.2 (C), 139.5 (C), 129.3 (CH), 128.7
H
) 7.20 ꢀ 7.10 (2 H, m, Ar
H),
6.70ꢀ6.65 (1 H, m, Ar
H
J
H
H
2), 3.95 (1 H,
13
br. s., N
H
), ppm; C NMR (100 MHz, CDCl3)
δ
(CH), 127.6 (CH), 127.3 (CH), 117.6 (CH), 112.5 (CH), 48.4 (CH2) ppm; m/z (ESI) 184.1
(M+ + H, 100%), 198.1.
N-Phenethylaniline 20 18
NꢀPhenethylaniline was synthesised via the same procedure as
.
previously described with 2ꢀphenylethanol (122 µL, 122 mg, 1.00 mmol), aniline (182 µL,
186 mg, 2.00 mmol), tricarbonyl(1,3ꢀdi(4ꢀmethoxyphenyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀ
one)iron (48.6 mg, 0.100 mmol) and trimethylamine Nꢀoxide (6.75 mg, 0.09 mmol). Column
chromatography, eluted with 0ꢀ5% ethyl acetate in pentane, gave the product as a colourless
oil (181mg, 0.920 mmol, 92.0%). HRMS (ESIꢀTOF) m/z: [M + H]+ Calcd for C14H16N
1
198.1277; Found 198.1280; H NMR (400 MHz, CDCl3)
δ
7.25 ꢀ 7.40 (2 H, m, Ar
H
) 7.09 ꢀ
), 3.62 (1 H, br.
2) ppm; 13C NMR (101 MHz,
7.24 (5 H, m, Ar
s., N ), 3.36 (2 H, t,
CDCl3)
198 (M+ + H, 100%).
H
), 6.69 (1 H, t,
J
=8.0 Hz, Ar
H
), 6.58 (2 H, d,
J
=8.0 Hz, ArH
H
J
=7.0 Hz, C
H
2), 2.87 (2 H, t,
J
=7.0 Hz, C
H
δ
148.1, 139.5, 129.4, 128.9, 128.7, 126.5, 117.6, 113.1, 45.1, 35.6 ppm; m/z (EI)
N-(3-Phenylpropyl)aniline 21 18
Nꢀ(3ꢀPhenylpropyl)aniline was synthesised via the same
.
procedure as previously described with 3ꢀphenylꢀ1ꢀpropanol (136 mg, 1.00 mmol), aniline
(182 µL, 186 mg,2.00 mmol), tricarbonyl(1,3ꢀdi(4ꢀmethoxyphenyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀ
indenꢀ2ꢀone)iron (48.6 mg, 0.100 mmol) and trimethylamine Nꢀoxide (6.75 mg, 0.09 mmol).
Column chromatography eluted with 0ꢀ5% ethyl acetate in pentane gave the product as a
colourless oil (201 mg, 0.952 mmol, 95.2%). HRMS (ESIꢀTOF) m/z: [M + H]+ Calcd for
1
C15H18N 212.1434; Found 212.1436; H NMR (300 MHz, CDCl3)
δ
7.23 ꢀ 7.33 (2 H, m,
), 6.57 (2 H, d, =7.6 Hz, Ar ),
2), 2.73 (2 H, t, =7.5 Hz, C 2), 1.95 (2 H,
ArH), 7.10 ꢀ 7.23 (5 H, m, Ar
H
), 6.68 (1 H, t,
J
=7.3 Hz, Ar
H
J
H
3.59 (1 H, br. s., N
H), 3.14 (2 H, t,
J
=6.9 Hz, C
H
J
H
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quin,
117.2, 112.8, 43.4, 33.4, 32.0 ppm; m/z (EI) 212 (M+ + H, 100%).
J=7.3 Hz, CH δ 148.4, 141.7, 129.2, 128.4, 126.0,
2) ppm; 13C NMR (75 MHz, CDCl3)
6
7
8
9
N-(4-Phenylbutyl)aniline 22 19
Nꢀ(4ꢀPhenylbutyl)aniline was synthesised via the same
.
procedure as previously described with 4ꢀphenylꢀ1ꢀbutanol (152 µL, 150 mg, 1.00 mmol),
aniline (182 µL, 186 mg, 2.00 mmol), tricarbonyl(1,3ꢀdi(4ꢀtrifluoromethylphenyl)ꢀ4,5,6,7ꢀ
tetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (56.2 mg, 0.100 mmol) and trimethylamine Nꢀoxide (6.75
mg, 0.09 mmol). Column chromatography eluted with 0ꢀ5% ethyl acetate in pentane gave the
product as a colourless oil (183 mg, 0.816 mmol, 81.6%). HRMS (ESIꢀTOF) m/z: [M + H]+
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
1
Calcd for C16H20N 226.1590; Found 226.1589; νmax 3399, 2930, 1601 cmꢀ1; H NMR (300
MHz, CDCl3)
Ar ), 6.57 (2 H, d,
(2 H, t, =7.2 Hz, C
δ
7.23 ꢀ 7.38 (2 H, m, Ar
=7.8 Hz, Ar ), 3.54 (1 H, br. s., N
2), 1.54 ꢀ 1.84 (4 H, m, C
2) ppm; 13C NMR (75 MHz, CDCl3)
H
), 7.03 ꢀ 7.22 (5 H, m, Ar
H
), 6.7 (1 H, t,
J
=7.2 Hz,
2), 2.65
148.5,
H
J
H
H), 3.11 (2 H, t,
J
=6.6 Hz, C
H
J
H
H
δ
142.3, 129.3, 128.5, 128.4, 125.9, 117.2, 112.7, 43.9, 35.7, 29.2, 29.0 ppm; m/z (ESI) 226
(M++ 1, 100%).
N-(3-(4-Methoxyphenyl)propyl)aniline 23 20
.
Nꢀ3ꢀ(4ꢀMethoxyphenyl)propyl)aniline was
synthesised via the previously described method using 3ꢀ(4ꢀmethoxyphenyl)ꢀ1ꢀpropanol (166
mg, 1.00 mmol), aniline (182 µL, 2.00 mmol,), tricarbonyl(1,3ꢀdi(4ꢀtrifluoromethylphenyl)ꢀ
4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (56.2 mg, 0.100 mmol) and trimethylamine Nꢀoxide
(6.75 mg, 0.09 mmol). Column chromatography eluted with 0ꢀ5% ethyl acetate in pentane
afforded the product as a colourless oil (226mg, 0.938 mmol, 94%). HRMS (ESIꢀTOF) m/z:
1
[M + H]+ Calcd for C16H20NO 242.1539; Found 242.1536; νmax 3399, 2931, 1602 cmꢀ1; H
NMR (500 MHz, CDCl3)
H, d, =8.5 Hz, Ar ), 6.68 (1 H, t,
s, OCH3), 3.59 (1 H, br. s., N
1.91 (2 H, quin, =7.3 Hz, C
δ
7.13 ꢀ 7.20 (2 H, m, Ar
=7.3 Hz, Ar ), 6.57 (2 H, d,
=7.0 Hz, C 2), 2.67 (2 H, t,
157.9, 148.4, 133.7,
H
), 7.11 (2 H, d,
=7.6 Hz, Ar
=7.6 Hz, C
J
=8.5 Hz, Ar
), 3.78 (3 H,
2),
H), 6.83 (2
J
H
J
H
J
H
H
H
), 3.12 (2 H, t,
J
H
J
H
13
J
2) ppm; C NMR (126 MHz, CDCl3)
δ
129.3, 129.2, 117.2, 113.9, 112.8, 55.3, 43.4, 32.5, 31.3 ppm; m/z (ESI) 242 (M+ + 1, 100%).
N-(4-Methoxyphenethyl)aniline 24 21
.
Nꢀ(4ꢀMethoxyphenethyl)aniline was prepared via the
general procedure using aniline (182 µL, 186 mg, 2.00 mmol),4ꢀmethoxyphenethyl alcohol
(152 mg, 1.00 mmol), tricarbonyl(1,3ꢀdi(4ꢀmethoxyphenyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀ
one)iron (48.6 mg, 0.100 mmol) and trimethylamine Nꢀoxide (6.75 mg, 0.09 mmol). Flash
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chromatography with 0ꢀ5% ethyl acetate in pentane gave the product as a colourless oil (216
mg, 0.956 mmol, 95.6%). νmax 3418, 2928, 1601 cmꢀ1; 1H NMR (500 MHz, CDCl3)
7.23 (4 H, m, Ar ), 6.86 (2 H, d, =8.7 Hz, Ar ), 6.70 (1 H, t, =7.3 Hz, ?H), 6.61 (2 H, d,
=9.3 Hz, Ar ), 3.80 (3 H, s, OC 3), 3.65 (1 H, br. s. N ), 3.36 (2 H, t, =6.9 Hz, C 2),
2.86 (2 H, t, =6.9 Hz, C 158.2, 148.1, 131.3, 129.7,
2) ppm; 13C NMR (126 MHz, CDCl3)
129.3, 117.4, 114.0, 113.0, 55.3, 45.2, 34.6 ppm; m/z 227 (M+H, 100%).
δ 7.08 ꢀ
H
J
H
J
J
H
H
H
J
H
J
H
δ
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
4-Methoxy-N-(3-(4-methoxyphenyl)propyl)aniline
25 22
.
4ꢀMethoxyꢀNꢀ(4ꢀ
(methoxyphenyl)propyl)aniline was synthesised via the previously described method with 3ꢀ
(4ꢀmethoxyphenyl)ꢀ1ꢀpropanol (166 mg, 1.00 mmol), anisidine (246 mg, 2.00 mmol),
tricarbonyl(1,3ꢀdi(4ꢀmethoxyphenyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (48.6 mg, 0.100
mmol) and trimethylamine Nꢀoxide (6.75 mg, 0.09 mmol). Column chromatography eluted
with 0ꢀ5% ethyl acetate in pentane afforded the product as a colourless oil (268 mg, 0.989
mmol, 99%).
ν
max 3401, 2932, 1602 cmꢀ1; 1H NMR (500 MHz, CDCl3)
δ
7.11 (2 H, d,
J
J
=8.5
=8.9
Hz, Ar
H
), 6.83 (2 H, d,
), 3.79 (3 H, s, OC
2), 1.89 (2 H, quin,
J
=8.5 Hz, Ar
H
), 6.76 (8 H, d,
J
=8.9 Hz, Ar
H
), 6.55 (2 H, d,
Hz, ArH
H
3), 3.74 (3 H, s, OC
H3), 3.08 (2 H, t,
J
=7.0 Hz, NCH2), 2.66 (2
13
H, t,
J
=7.6 Hz, C
H
J
=7.3 Hz, CH2C
H
2CH2) ppm; C NMR (126 MHz,
CDCl3)
δ
157.9, 152.1, 142.7, 133.8, 129.3, 114.9, 114.1, 113.8, 55.8, 55.3, 44.4, 32.5, 31.4
ppm; m/z (ESI) 272 (M+ + H, 100%).
4-Chloro-N-(3-(4-methoxyphenyl)propyl)aniline
26 23
.
4ꢀChloroꢀNꢀ(3ꢀ(4ꢀ
methoxyphenyl)propyl)aniline was synthesised via the previously described method using 3ꢀ
(4ꢀmethoxyphenyl)ꢀ1ꢀpropanol (166 mg, 1.00 mmol), 4ꢀchloroaniline (255 mg, 2.00 mmol),
tricarbonyl(1,3ꢀdi(4ꢀmethoxyphenyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (48.6 mg, 0.100
mmol) and trimethylamine Nꢀoxide (6.75 mg, 0.09 mmol). Column chromatography eluted
with 0ꢀ5% ethyl acetate in pentane gave the product as a clear oil (262 mg, 0.953 mmol,
95.3%). HRMS (ESIꢀTOF) m/z: [M + H]+ Calcd for C16H19ClNO 276.1150 & 278.1120;
1
Found 276.1151 & 278.1121; νmax 3402, 2933, 1598 cmꢀ1; H NMR (500 MHz, CDCl3)
δ
7.05ꢀ7.07 (4 H, m, Ar
H, s, OC 3), 3.60 (1 H, br. s., N
2), 1.89 (2 H, quin,
H
), 6.83 (2 H, d,
J
=8.5 Hz, Ar
H
), 6.46 (2 H, d,
=7.0 Hz, NC 2), 2.65 (2 H, t,
157.9, 146.9,
J
=8.9 Hz, Ar
H
), 3.78 (3
H
H
), 3.08 (2 H, t,
J
H
J=7.6 Hz,
13
C
H
J=7.3 Hz, C
H2) ppm; C NMR (126 MHz, CDCl3)
δ
133.5, 129.3, 129.0, 121.7, 113.9, 113.8, 55.3, 43.4, 32.4, 31.1 ppm; m/z (ESI) 276 (M+ + H,
100%), 278 (M+ + H, 40%).
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N-(3-(4-Methoxyphenyl)propyl)-N-methylaniline 27.20
Nꢀ(3ꢀ(4ꢀMethoxyphenyl)propyl)ꢀNꢀ
6
7
8
9
methylaniline was prepared via the general procedure using Nꢀmethylaniline (217 µL, 214
mg, 2.00 mmol), 3ꢀ(4ꢀmethoxyphenyl)ꢀ1ꢀpropanol (166 mg, 1.00 mmol), tricarbonyl(1,3ꢀ
di(4ꢀmethoxyphenyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (48.6 mg, 0.100 mmol) and
trimethylamine Nꢀoxide (6.75 mg, 0.09 mmol). Flash chromatography with 0ꢀ5% ethyl
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
acetate in pentane gave
(127 mg, 0.498 mmol, 49.8%). HRMS (ESIꢀTOF) m/z: [M + H]+ Calcd for C17H21NO
256.1696; Found 256.1698; 7.20
max 3412, 2932, 1602 cmꢀ1; 1H NMR (500 MHz, CDCl3)
(2 H, t, =7.32 Hz, Ar ), 7.09 (2 H, d, =8.0 Hz, Ar ), 6.82 (2 H, d, =7.7 Hz, Ar ), 6.57 ꢀ
6.71 (3 H, m, Ar ), 3.78 (3 H, s, OC 3), 3.31 (2 H, t, =7.4 Hz, NC
2.58 (2 H, t, =7.6 Hz, C 2), 1.87 (2 H, quin, =7.5 Hz, C
CDCl3)
ppm; m/z 256 (M+H, 100%).
Nꢀ(3ꢀ(4ꢀmethoxyphenyl)propyl)ꢀNꢀmethylaniline as a colourless oil
ν
δ
J
H
J
H
J
H
H
H
J
H2), 2.90 (3 H, s, NCH3),
13
J
H
J
H
2), ppm; C NMR (126 MHz,
δ
157.9, 149.4, 133.9, 129.3, 129.2, 116.0, 113.8, 112.3, 55.3, 52.2, 38.3, 32.4, 28.4
N-Cyclopentylaniline 28 24
NꢀCyclopentylaniline was prepared via the general procedure
.
using aniline (182 µL, 186 mg, 2.00 mmol), cyclopentanol (91 µL, 85 mg, 1.00 mmol),
tricarbonyl(1,3ꢀdiphenylꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (42.6 mg, 0.100 mmol) and
trimethylamine Nꢀoxide (6.75 mg, 0.09 mmol). Flash chromatography with 0ꢀ5% ethyl
acetate in pentane gave
90.1%). HRMS (ESIꢀTOF) m/z: [M + H]+ Calcd for C11H16N 162.1277; Found 162.1277;
max 3406, 2955, 160 cmꢀ1; 1H NMR (500 MHz, CDCl3)
7.16 (2 H, t, =7.7 Hz, Ar ), 6.67
(1 H, t, =7.3 Hz, Ar ), 6.60 (2 H, d, =7.7 Hz, Ar ), 3.78 (1 H, quin, =6.1 Hz, NC ),
3.631 (1 H, br. S, N ), 2.02 (2 H, dd, =12.4, 6.2 Hz, C 2), 1.39 ꢀ 1.83 (6 H, m, C 2) ppm;
148.1, 129.2, 116.9, 113.2, 54.7, 33.6, 24.1 ppm; m/z 162
Nꢀcyclopentylaniline amine as a colourless oil (145 mg, 0.901 mmol,
ν
δ
J
H
J
H
J
H
J
H
H
J
H
H
13C NMR (126 MHz, CDCl3)
δ
(M+H, 100%).
N-Cyclohexylaniline 29.19 NꢀCyclohexylamine was synthesised via the general method from
aniline (182 µL, 186 mg, 2.00 mmol), cyclohexane (105 µL, 100 mg, 1.00 mmol),
tricarbonyl(1,3ꢀdi(4ꢀmethoxyphenyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (48.6 mg, 0.100
mmol) and trimethylamine Nꢀoxide (6.75 mg, 0.09 mmol). Flash chromatography eluted with
0ꢀ5% ethyl acetate in pentane gave Nꢀcyclohexylaniline as a yellow oil (166 mg, 0.949
mmol, 95%). HRMS (ESIꢀTOF) m/z: [M + H]+ Calcd for C12H18N 176.1434; Found
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176.1438; νmax 3367, 2925, 1600 cmꢀ1; H NMR (500 MHz, CDCl3)
δ
7.07 ꢀ 7.20 (2 H, m,
), 3.23 (1 H,
2), 1.55 ꢀ 1.68 (1
2) ppm. 13C NMR (126 MHz,
147.5, 129.4, 116.9, 113.2, 51.8, 33.6, 26.1, 25.1 ppm; m/z 176 (M+H, 100%).
ArH
), 6.61 ꢀ 6.69 (1 H, m, Ar
=10.2, 3.7 Hz, NC ), 1.94 ꢀ 2.12 (2 H, m, C
2), 1.28 ꢀ 1.42 (2 H, m, C 2), 1.04 ꢀ 1.27 (3 H, m, C
H
), 6.54ꢀ6.68 (2 H, m, Ar
H), 3.47 (1 H, br. s., NH
tt,
J
H
H2), 1.72ꢀ1.76 (2 H, m, CH
H, m, C
CDCl3)
H
H
H
δ
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
N-Phenylcycloheptanamine 30 25
NꢀPhenylcycloheptylanimine was prepared via the general
.
procedure using aniline (182 µL, 186 mg, 2.00 mmol), cyclopheptanol (238 mg, 1.00 mmol),
tricarbonyl(1,3ꢀdi(4ꢀmethoxyphenyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (48.6 mg, 0.100
mmol) and trimethylamine Nꢀoxide (6.75 mg, 0.09 mmol). Flash chromatography with 0ꢀ2%
ethyl acetate in pentane gave
mmol, 96.3%? %). HRMS (ESIꢀTOF) m/z: [M + H]+ Calcd for C13H20N 190.1590; Found
190.1592; 7.25 (2 H, t, =7.9 Hz,
max 3404, 2922, 1600 cmꢀ1; 1H NMR (500 MHz, CDCl3)
Ar ), 6.75 (1 H, t, ), 3.55
(1 H, m, NC ), 2.03 ꢀ 2.21 (2 H, m, C
Nꢀphenylcycloheptylanimine as a colourless oil (182 mg, 0.963?
ν
δ
J
H
J
=7.3 Hz, Ar
H
), 6.64 (2 H, d,
J
=7.8 Hz, Ar
H
), 3.65 (1 H, br. s., NH
13
H
H2), 1.48 ꢀ 1.88 (10 H, m, C
H
2) ppm; C NMR (126
MHz, CDCl3)
100%).
δ 147.4, 129.3, 116.8, 113.3, 53.7, 34.9, 28.5, 24.51 ppm; m/z 190 (M+H,
N-Phenyl-1,2,3,4-tetrahydronaphthalen-2-amine
31 26
.
NꢀPhenylꢀ1,2,3,4ꢀ
tetrahydronaphthalenꢀ2ꢀamine was prepared via the general procedure using aniline (182 µL,
186 mg, 2.00 mmol), βꢀtetralol (148 mg, 1.00 mmol, 1.00), tricarbonyl(1,3ꢀdi(4ꢀ
methoxyphenyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (48.6 mg, 0.100 mmol) and
trimethylamine Nꢀoxide (6.75 mg, 0.09 mmol). Flash chromatography with 0ꢀ5% ethyl
acetate in pentane gave
(131 mg, 0.587 mmol, 58.7%). HRMS (ESIꢀTOF) m/z: [M + H]+ Calcd for C16H18N
224.1434; Found 224.1432; νmax 3354, 3033, 1600 cmꢀ1; 1H NMR (300 MHz, CDCl3)
7.03 ꢀ
7.23 (6 H, m, Ar ), 6.58 ꢀ 6.77 (3 H, m, Ar ), 3.75 ꢀ 3.92 (1 H, m, NC ), 3.69 (1 H, br. s.,
), 3.22 (1 H, dd, =16.2, 4.5 Hz, C H), 2.92 (2 H, t, =6.5 Hz, ArC
), 2.10 ꢀ 2.29 (1 H, m, C 2), 1.69 ꢀ 1.87 (1 H, m, C
Nꢀphenylꢀ1,2,3,4ꢀtetrahydronaphthalenꢀ2ꢀamine as a colourless oil
δ
H
H
H
N
H
J
H
J
H
2), 2.69 (1 H, dd,
J
=16.2, 8.3 Hz, CH
H
H
H
2) ppm; 13C NMR
(75 MHz, CDCl3)
δ
147.2, 135.9, 134.7, 129.5, 129.4, 128.8, 126.1, 125.9, 117.3, 113.4,
48.5, 36.5, 28.8, 27.5 ppm; m/z 224 (M+H, 100%).
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1-Phenylpyrrolidine 32.19 1ꢀPhenylpyrrolidine was prepared via the general procedure using
aniline (91 µL, 93 mg, 1.00 mmol), 1,4ꢀbutanediol (180 mg, 2.00 mmol), tricarbonyl(1,3ꢀ
diphenylꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (42.6 mg, 0.100 mmol) and trimethylamine
Nꢀoxide (6.75 mg, 0.09 mmol). Flash chromatography with 0ꢀ2% ethyl acetate in pentane
1
gave 1ꢀphenylpyrrolidine as a colourless oil (50 mg, 0.34 mmol, 34%). H NMR (500 MHz,
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
CDCl3)
Ar ), 3.28 (4 H, t,
ppm 148.0, 129.1, 115.4, 111.6, 47.6, 25.5 ppm; m/z 148 (M+H, 100%).
δ
7.17 ꢀ 7.34 (2 H, m, Ar
H
), 6.65 (1 H, t,
J
=7.3 Hz, Ar
H), 6.57 (2 H, d, J=7.9 Hz,
H
J
=6.6 Hz, NC 2), 2.00 (4 H, m, C
H
H
2) ppm; 13C NMR (126 MHz, CDCl3)
δ
1-Phenylazapine 33 27
1ꢀPhenylpyrrolidine was prepared via the general procedure using
.
aniline (91. µL, 93 mg, 1.00 mmol),1,6ꢀhexanediol (210 µL, 236 mg, 2.00 mmol),
tricarbonyl(1,3ꢀdi(4ꢀmethoxyphenyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (48.6 mg, 0.100
mmol) and trimethylamine Nꢀoxide (6.75 mg, 0.09 mmol). Flash chromatography with 0ꢀ2%
ethyl acetate in pentane gave 1ꢀphenylpyrrolidine as a colourless oil (75 mg, 0.43 mmol,
1
43%). HRMS (ESIꢀTOF) m/z: [M + H]+ Calcd for C12H18N 176.1434; Found 176.1436; H
NMR (500 MHz, CDCl3)
6.62 (1 H, t, =7.3 Hz, Ar
1.58 (4 H, m, C
27.8, 27.2 ppm; m/z (ESI) 176 (M+H, 100%).
δ
7.20 (2 H, dd,
J
=8.8, 7.2 Hz, Ar
H
), 6.69 (2 H, d,
J
=7.9 Hz, Ar
2), 1.51 ꢀ
2) ppm; C NMR (126 MHz, CDCl3) δ 148.9, 129.2, 115.1, 111.1, 49.0,
H),
J
H
), 3.41 ꢀ 3.50 (4 H, m, NCH2), 1.72 ꢀ 1.85 (4 H, m, CH
13
H
N-(Pent-4-en-1-yl)aniline 37 28
. Nꢀ(Pentꢀ4ꢀenꢀ1ꢀyl)aniline was synthesised through the general
procedure using aniline (182 µL, 186 mg, 2.00 mmol), pentenꢀ1ꢀol (105 µL, 86.0 mg, 1.00
mmol), tricarbonyl(1,3ꢀdi(trimethylsilyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (42.0 mg,
o
0.100 mmol) and trimethylamine Nꢀoxide (15.0 mg, 0.200 mmol) but at 120 C rather than
o
140 C.
Nꢀ(Pentꢀ4ꢀenꢀ1ꢀyl)aniline was isolated through column chromatography eluted with
0ꢀ20% ethyl acetate in pentane to give a light brown oil (128 mg, 0.748 mmol, 74.8%).
HRMS (ESIꢀTOF) m/z: [M + H]+ Calcd for C11H16N 162.1277; Found 162.1278; νmax 3408
(NꢀH), 2928, 2858, 1601 cmꢀ1; 1H NMR (500 MHz, CDCl3)
6.69 (1 H, t, =7.3 Hz, Ar ), 6.60 (2 H, d, =7.8 Hz, Ar ), 5.84 (1 H, ddt,
Hz, CH2C =CH2), 5.06 (1 H, dd, =17.2, 1.7 Hz, CH=CH ), 5.00 (1 H, d,
CH=C H), 3.61 (1 H, br. s., N ), 3.13 (2 H, t, =7.1 Hz, NHC 2), 2.17 (2 H, q,
CH2C 2CH=CH2), 1.72 (2 H, quin,
δ
7.17 (2 H, t,
J
=7.9 Hz, Ar
=17.0, 10.3, 6.6
=10.2 Hz,
=6.9 Hz,
H),
J
H
J
H
J
H
J
H
J
H
H
J
H
J
H
J
=7.3 Hz, CH2C
H
2CH2) ppm; 13C NMR (126 MHz,
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CDCl3)
([M+H]+).
δ
148.4, 138.0, 129.2, 117.2, 114.7, 112.7, 43.4, 31.3, 28.6 ppm; m/z (ESI) 162.1
6
7
8
9
N-(6-(trimethylsilyl)hex-5-yn-1-yl)aniline 38 29
Nꢀ(6ꢀ(Trimethylsilyl)hexꢀ5ꢀynꢀ1ꢀyl)aniline
.
was synthesised through the general procedure using aniline (182 µL, 186 mg, 2.00 mmol),
6ꢀ(trimethylsilyl)hexꢀ5ꢀynꢀ1ꢀol (166 mg, 1.00 mmol), tricarbonyl(1,3ꢀdi(trimethylsilyl)ꢀ
4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (42.0 mg, 0.100 mmol) and trimethylamine Nꢀoxide
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
(15.0 mg, 0.200 mmol).
Nꢀ(6ꢀ(Trimethylsilyl)hexꢀ5ꢀynꢀ1ꢀyl)aniline was isolated via column
chromatography (196 mg, 0.799 mmol, 79.9%). HRMS (ESIꢀTOF) m/z: [M + H]+ Calcd for
C15H24NS 246.1673; Found 246.1671; νmax 3385 (NꢀH), 2933, 2169, 1601 cmꢀ1; 1H NMR
(500 MHz, CDCl3)
=8.1 Hz, Ar ), 3.20 (1H, brs, NH), 3.00 (2 H, t,
2CCSi), 1.77 (2 H, quin, =7.0 Hz, C 2CH2CH2CC), 1.67 (2 H, quin,
2CH2CC), 0.20 (9 H, s, Si(C 148.3, 129.2,
3)3) ppm; 13C NMR (126 MHz, CDCl3)
δ
7.21 (2 H, t,
J
=7.6 Hz, Ar
H
) 6.73 (1 H, t,
J
=7.3 Hz, Ar
H
), 6.64 (2 H, d,
=7.0 Hz,
=7.0 Hz,
J
H
J
=7.0 Hz, NHC
H2), 2.32 (2 H, t,
J
C
H
H
J
H
J
C
H
δ
117.1, 112.6, 106.9, 84.9, 43.3, 28.5, 26.1, 19.6, 0.1 ppm; m/z (ESI) 246.2 ([M+H]+). At 120
oC, the yield was 38%.
4-Methoxy-N-(pent-4-en-1-yl)aniline
39.
4ꢀMethoxyꢀ
N
ꢀ(pentꢀ4ꢀenꢀ1ꢀyl)aniline
was
synthesised via the general procedure using
p
ꢀanisidine (245 mg, 2.00 mmol), 4ꢀpentenꢀ1ꢀol
(86 mg, 1.00 mmol), tricarbonyl(1,3ꢀdi(trimethylsilyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀ
one)iron (42.0 mg, 0.100 mmol) and trimethylamine Nꢀoxide (15.0 mg, 0.2 mmol). The
product was isolated via column chromatography with 0ꢀ40% ethyl acetate in pentane to give
4ꢀmethoxyꢀ
HRMS (ESIꢀTOF) m/z: [M + H]+ Calcd for C12H18NO 192.1383; Found 192.1395; νmax
3390, 2931, 1640 cmꢀ1; 1H NMR (500 MHz, CDCl3)
6.78 (2 H, d, =8.9 Hz, Ar ), 6.58 (2
), 5.70 ꢀ 5.97 (1 H, m, CH=CH2), 5.05 (1 H, d, =17.0 Hz, CH=CH ),
H), 3.75 (3 H, s, OCH3), 3.09 (2 H, t, =8.7 Hz, NHCH2),
=7.3 Hz, CH2CH2CH2), 1.46 ꢀ 1.91
152.0, 142.7, 138.1, 115.0, 114.9,
Nꢀ(pentꢀ4ꢀenꢀ1ꢀyl)aniline as a colourless oil (134 mg, 0.698 mmol, 69.8%).
δ
J
H
H, d,
J
=8.9 Hz, Ar
H
J
H
4.99 (1 H, d,
2.17 (2 H, q,
J
=10.2 Hz, CH=C
H
J
J
=6.1 Hz, CH2CH=CH2), 1.70 (2 H, quin, J
13
(1 H , br. s., NH) ppm; C NMR (126 MHz, CDCl3)
δ
114.1, 55.9, 44.5, 31.4, 28.8 ppm; m/z (ESI) 192 (M+H, 100%).
4-Chloro-N-(pent-4-en-1-yl)aniline 40. 4ꢀChloroꢀNꢀ(pentꢀ4ꢀenꢀ1ꢀyl)aniline was synthesised
through the general procedure using 4ꢀchloroaniline (255 mg, 2.00 mmol), pentenꢀ1ꢀol (105
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µL, 86.0 mg, 1.00 mmol), tricarbonyl(1,3ꢀdi(trimethylsilyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀ
one)iron (42.0 mg, 0.100 mmol) and trimethylamine Nꢀoxide (15.0 mg, 0.200 mmol). 4ꢀ
6
7
ChloroꢀNꢀ(pentꢀ4ꢀenꢀ1ꢀyl)aniline was isolated through column chromatography eluted with
8
9
0ꢀ20% ethyl acetate in pentane to give a light brown oil (82.0 mg, 0.421 mmol, 42.1 %).
HRMS (ESIꢀTOF) m/z: [M + H]+ Calcd for C11H15ClN 196.0888 + 198.0858; Found
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
196.0886 + 198.0856; 1H NMR (600 MHz, CDCl3)
H, d, =8.3 Hz, Ar ), 5.68 (1 H, ddt, =17.0, 10.3, 6.6 Hz, C
Hz, CH=CH ), 4.85 (1 H, d, =10.2 Hz, CH=C
=7.0 Hz, NHC 2), 2.01 (2 H, q,
2CH2) ppm; 13C NMR (151 MHz, CDCl3)
δ
6.96 (2 H, d,
=CH2), 4.91 (1 H, d,
H), 3.49 (1 H, br. s., N ), 2.94 (2 H, t,
2CH=CH2), 1.55 (2 H, quin, =7.1 Hz,
146.8, 137.7, 128.9, 121.5, 115.1, 113.6,
J
=8.3 Hz, Ar
H
), 6.36 (2
J
H
J
H
J
=17.3
H
J
H
H
J
H
J
=7.1 Hz, CH2C
H
J
CH2C
H
δ
43.3, 31.1, 28.3 ppm; m/z 196 (M+H (35Cl), 100%), 198 (M + H (37Cl), 33%).
N-Benzylpent-4-en-1-amine 41. NꢀBenzylpentꢀ4ꢀenꢀ1ꢀamine was synthesised via the general
procedure using benzylamine (109 µL, 107 mg, 1.00 mmol), 4ꢀpentenꢀ1ꢀol (208 µL, 172 mg,
2.00 mmol), tricarbonyl(1,3ꢀdi(trimethylsilyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (42.0
mg, 0.100 mmol) and trimethylamine Nꢀoxide (15.0 mg, 0.2 mmol). The product was isolated
using column chromatography eluted with 0ꢀ100% ethyl acetate in pentane to give
Nꢀ
benzylpentꢀ4ꢀenꢀ1ꢀamine as a colourless oil (158 mg, 0.903 mmol, 90.3%). HRMS (ESIꢀ
TOF) m/z: [M + H]+ Calcd for C12H18N 176.1434; Found 176.1433; νmax 3076, 3064, 1640
1
cmꢀ1; H NMR (500 MHz, CDCl3)
δ
7.28 ꢀ 7.38 (4 H, m, ArH), 7.20 ꢀ 7.28 (1 H, m, ArH),
=17.0, 10.2, 6.7 Hz, CH=CH2), 4.90 ꢀ 5.05 (2 H, m, =CH2), 3.78 (2 H, s,
PhCH2), 2.65 (2 H, t, =7.2 Hz, NHCH2CH2CH2), 2.10 (2 H, q, =7.0 Hz, NHCH2), 1.61 (2
H, quin,
=7.4 Hz, , NHCH2CH2CH2), 1.47 (1 H, br. s., NH); 13C NMR (126 MHz, CDCl3)
5.81 (1 H, ddt,
J
J
J
J
δ
ppm 140.49, 138.49, 128.4, 128.1, 126.9, 114.6, 54.0, 48.9, 31.5, 29.2; m/z 176 (M+H,
100%).
N-Benzyl-6-(trimethylsilyl)hex-5-yn-1-amine 42.
NꢀBenzylꢀ6ꢀ(trimethylsilyl)hexꢀ5ꢀynꢀ1ꢀ
amine was synthesised via the general procedure using benzylamine (107 mg, 1.00 mmol), 6ꢀ
(trimethylsilyl)hexꢀ5ꢀynꢀ1ꢀol (332 mg, 2.00 mmol), tricarbonyl(1,3ꢀdi(trimethylsilyl)ꢀ4,5,6,7ꢀ
tetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (42.0 mg, 0.100 mmol) and trimethylamine Nꢀoxide (15.0
mg, 0.2 mmol). The product was isolated via column chromatography eluted with 0ꢀ60%
ethyl acetate in pentane to give
Nꢀbenzylꢀ6ꢀ(trimethylsilyl)hexꢀ5ꢀynꢀ1ꢀamine as a colourless
oil (51.0 mg, 0.197 mmol, 20%). HRMS (EI) m/z: [M + H]+ Calcd for C16H26NSi 260.1829;
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1
Found 260.1829; νmax 3301, 2955 cmꢀ1; H NMR (500 MHz, CDCl3)
δ
7.22 ꢀ 7.31 (4 H, m,
=6.9 Hz,
=6.9 Hz, CH2CCTMS), 1.45 ꢀ 1.59 (4 H, m, CH2CH2CH2CH2),
1.41 (1 H, br. s., NH), 0.07 (9 H, s, CCSi(CH3)3 ppm; 13C NMR (126 MHz, CDCl3)
140.41,
Ar
H), 7.11 ꢀ 7.22 (1 H, m, ArH), 3.72 (2 H, s, PhCH2NH), 2.58 (2 H, t, J
NHCH2CH2), 2.17 (2 H, t,
J
δ
128.40, 128.1, 126.9, 107.2, 84.6, 54.0, 48.8, 29.2, 26.4, 19.8, 0.1 ppm; m/z (ESI) 260 (M+H,
100%).
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
N-Benzylpentan-1-amine 43 7b
procedure using benzylamine (109 µL, 107 mg, 1.00 mmol), 1ꢀpentanol (217
.
N
ꢀBenzylpentanꢀ1ꢀamine was synthesised via the general
L, 172 mg,
μ
2.00 mmol), tricarbonyl(1,3ꢀdi(trimethylsilyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (42.0
mg, 0.100 mmol) and trimethylamine Nꢀoxide (15.0 mg, 0.2 mmol). The product was isolated
using column chromatography eluted with 0ꢀ20% ethyl acetate in pentane to give
Nꢀ
benzylpentanꢀ1ꢀamine as a colourless oil (92 mg, 0.518 mmol, 51.8%). HRMS (ESIꢀTOF)
m/z: [M + H]+ Calcd for C12H20N 178.1590; Found 178.1590; νmax 3310, 2928, 1657 cmꢀ1;
1H NMR (500 MHz, CDCl3)
δ
7.06 ꢀ 7.45 (5 H, m, Ar
H
), 3.79 (2 H, s, PhC
), 1.43 ꢀ 1.60 (2 H, m, C 2), 1.31 (4 H, m, C
140.2, 128.4, 128.2,
H
2), 2.63 (2 H, t,
J
=7.3 Hz, NC
H
2CH2), 1.64 (1 H, br. s., N
H
H
H
2),
13
0.89 (3 H, t,
J
=6.5 Hz, CH2C
H
3) ppm; C NMR (126 MHz, CDCl3)
δ
127.0, 54.0, 49.4, 29.7, 29.6, 22.6, 14.1 ppm; m/z (ESI) 178 (M+H, 100%).
N-Benzyl-3-(4-methoxyphenyl)propan-1-amine 44. NꢀBenzylꢀ3ꢀ(4ꢀmethoxyphenyl)propanꢀ1ꢀ
amine was synthesised via the general procedure using benzylamine (107 mg, 1.00 mmol), 3ꢀ
(4ꢀmethoxyphenyl)ꢀ1ꢀpropanol (332 mg, 2.00 mmol), tricarbonyl(1,3ꢀdi(trimethylsilyl)ꢀ
4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (42.0 mg, 0.100 mmol) and trimethylamine Nꢀoxide
(15.0 mg, 0.2 mmol). The product was isolated via column chromatography eluted with 0ꢀ
60% ethyl acetate in pentane to give
colourless oil (129 mg, 0.506 mmol, 51%). HRMS (EI) m/z: [M + H]+ Calcd for C17H22NO
256.1696; Found 256.1701; 7.28
max 3061, 3028, 1611 cmꢀ1; 1H NMR (500 MHz, CDCl3)
ꢀ 7.35 (4 H, m, Ar ), 7.22 ꢀ 7.27 (1 H, m, Ar ), 7.09 (2 H, d, =8.5 Hz, Ar ), 6.82 (2 H, d,
=8.7 Hz, Ar ), 3.74 ꢀ 3.82 (5 H, m, OCH3 + PhCH2), 2.66 (2 H, t, =7.1 Hz, NHCH2), 2.60
=7.40 Hz, CH2CH2CH2), 1.49 ( 1 H, br. s,
Nꢀbenzylꢀ3ꢀ(4ꢀmethoxyphenyl)propanꢀ1ꢀamine as a
ν
δ
H
H
J
H
J
H
J
(2 H, t,
J
=7.7 Hz, ArCH2CH2), 1.81 (2 H, quin, J
13
NH) ppm; C NMR (126 MHz, CDCl3)
δ 157.7, 140.5, 134.3, 129.2, 128.4, 128.1, 126.9,
113.7, 55.2, 54.1, 48.9, 32.8, 31.8 ppm; m/z (ESI) 256 (M+H, 100%).
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1-Pentyl-4-phenylpiperidine 45. 1ꢀPentylꢀ4ꢀphenylpiperidine was synthesised via the general
procedure from 4ꢀphenylpiperidine (161 mg, 1.00 mmol),1ꢀpentanol (217 µL, 176 mg, 2.00
mmol), tricarbonyl(1,3ꢀdi(trimethylsilyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (42.0 mg,
0.100 mmol) and trimethylamine Nꢀoxide (15.0 mg, 0.2 mmol). The compound was purified
via column chromatography eluted with 0ꢀ40% ethyl acetate in pentane to give the product as
a colourless oil (225 mg, 0.974 mmol, 97.4%). HRMS (EI) m/z: [M + H]+ Calcd for C16H26N
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
232.2060; Found 232.2068;
ꢀ 7.41 (5 H, m, Ar ), 3.06 (2 H, d,
PhCH), 2.27 ꢀ 2.42 (2 H, m, NCH2CH2CH2), 2.02 (2 H, td,
1.91 (4 H, m, C 2), 1.47 ꢀ 1.62 (2 H, m, CH2CH2CH2), 1.20 ꢀ 1.44 (4 H, m, CH2), 0.91 (3 H,
t, 146.5, 128.4, 126.9, 126.1, 59.3,
=7.1 Hz, CH2CH3) ppm; 13C NMR (126 MHz, CDCl3)
ν
max 2954, 2871, 1662 cmꢀ1; 1H NMR (500 MHz, CDCl3)
=11.6 Hz, NCH2), 2.49 (1 H, ddd, =15.7, 10.5, 5.7 Hz,
=11.0, 4.2 Hz, NCH2), 1.72 ꢀ
δ 7.12
H
J
J
J
H
J
δ
54.5, 42.9, 33.5, 30.0, 26.8, 22.7, 14.1 ppm; m/z (ESI) 232 (M+H, 100%).
1-(Pent-4-en-1-yl)-4-phenylpiperidine 46. 1ꢀ(Pentꢀ4ꢀenꢀ1ꢀyl)ꢀ4ꢀphenylpiperidine was
synthesised via the general method using 4ꢀphenylpiperidine (161 mg, 1.00 mmol),4ꢀpentenꢀ
1ꢀol (208 µL, 172 mg, 2.00 mmol), tricarbonyl(1,3ꢀdi(trimethylsilyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀ
indenꢀ2ꢀone)iron (42.0 mg, 0.100 mmol) and trimethylamine Nꢀoxide (15.0 mg, 0.2 mmol).
The product was isolated using column chromatography eluted with 0ꢀ30% ethyl acetate in
pentane to give 1ꢀ(pentꢀ4ꢀenꢀ1ꢀyl)ꢀ4ꢀphenylpiperidine as a colourless oil (218 mg, 0.952
mmol, 95.2%). HRMS (ESIꢀTOF) m/z: [M + H]+ Calcd for C16H24N 230.1903; Found
1
230.1901; νmax 2933, 2801, 1640 cmꢀ1 ; H NMR (600 MHz, CDCl3)
δ
7.30 ꢀ 7.34 (2 H, m,
), 5.87 (1 H, ddt, =17.0, 10.2, 6.7,
=17.1, 1.7 Hz, CH=CH2), 5.00 (1 H, d, =10.1 Hz,
=11.6 Hz, NCH2), 2.52 (1 H, tt, =10.5, 5.5 Hz, PhCH), 2.38 ꢀ 2.44
(2 H, m, NCH2CH2CH2), 2.12 (2 H, q, =7.1 Hz, CH2CH2CH=CH2), 2.04 ꢀ 2.10 (2 H, m,
CH2CH2), 1.79 ꢀ 1.91 (4 H, m, PhCHCH2), 1.68 (2 H, quin, =7.7 Hz, CH2CH2CH2) ppm;
146.5, 138.6, 128.4, 126.9, 126.1, 114.6, 58.7, 54.5, 42.9,
Ar
6.7 Hz, CH2CH=CH2), 5.07 (1 H, dd,
CH=CH2), 3.09 (2 H, d,
H
), 7.24 ꢀ 7.29 (2 H, m, Ar
H
), 7.19 ꢀ 7.24 (1 H, m, Ar
H
J
J
J
J
J
J
N
J
13C NMR (126 MHz, CDCl3)
δ
33.6, 31.9, 26.4 ppm; m/z 230 (M+H, 100%).
1-Benzyl-4-phenylpiperidine 47. 1ꢀBenzylꢀ4ꢀphenylpiperidine was synthesised via the general
procedure using 4ꢀphenylpiperidine (161 mg, 1.00 mmol), benzyl alcohol (207 µL, 216 mg,
2.00 mmol), tricarbonyl(1,3ꢀdi(trimethylsilyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (42.0
mg, 0.100 mmol) and trimethylamine Nꢀoxide (15.0 mg, 0.2 mmol). The product was isolated
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via column chromatography eluted with 0ꢀ30% ethyl acetate in pentane to give 1ꢀbenzylꢀ4ꢀ
phenylpiperidine as a colourless oil (239 mg, 0.952 mmol, 95.2%). HRMS (EI) m/z: [M +
1
H]+ Calcd for C18H22N 252.1747; Found 252.1748; νmax 2934, 2799 cmꢀ1; H NMR (500
6
7
8
9
MHz, CDCl3)
CH2NCH2), 2.42 ꢀ 2.55 (1 H, m, PhCH(CH2)2), 2.02 ꢀ 2.13 (2 H, m, CH2NCH2), 1.74 ꢀ 1.86
(4 H, m, CHCH2CH2) ppm; 13C NMR (126 MHz, CDCl3)
146.8, 138.7, 129.5, 128.6, 128.4,
δ 7.14 ꢀ 7.37 (10 H, m, ArH), 3.54 (2 H, s, CH2Ph), 3.01 (2 H, d, J=11.6 Hz,
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δ
127.2, 127.1, 126.3, 63.8, 54.5, 42.9, 33.7 ppm; m/z (ESI) 252 (M+H+, 100%).
1-(3-(4-Methoxyphenyl)propyl)-4-phenylpiperidine 48. 1ꢀ(3ꢀ(4ꢀMethoxyphenyl)propyl)ꢀ4ꢀ
phenylpiperidine was synthesised via the general procedure using 4ꢀphenylpiperidine (161
mg, 1.00 mmol),3ꢀ(4ꢀmethoxyphenyl)ꢀ1ꢀpropanol (332 mg, 2.00 mmol), tricarbonyl(1,3ꢀ
di(trimethylsilyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (42.0 mg, 0.100 mmol) and
trimethylamine Nꢀoxide (15.0 mg, 0.2 mmol). The 1ꢀ(3ꢀ(4ꢀmethoxyphenyl)propyl)ꢀ4ꢀ
phenylpiperidine was isolated via column chromatography eluted with 0ꢀ50% ethyl acetate in
pentane to give 1ꢀ(3ꢀ(4ꢀmethoxyphenyl)propyl)ꢀ4ꢀphenylpiperidine as a colourless oil (298
mg, 0.964 mmol, 96.4%). HRMS (EI) m/z: [M + H]+ Calcd for C21H28NO 310.2165; Found
1
310.2167; νmax 2933, 1612 cmꢀ1; H NMR (500 MHz, CDCl3)
δ
7.15 ꢀ 7.35 (5 H, m, Ar
), 3.78 (3 H, s, OC 3), 3.04 (2 H,
=7.6 Hz, NCH2CH2CH2), 2.47 (1 H, td, =10.1, 5.5
H),
7.11 (2 H, d,
J
=8.1 Hz, Ar
H
), 6.83 (2 H, d,
J
=8.2 Hz, Ar
H
H
d, =11.0 Hz, CH2NCH2), 2.59 (2 H, t,
J
J
J
Hz, PhCH(CH2)2), 2.35 ꢀ 2.42 (2 H, m, CH2), 1.97 ꢀ 2.09 (2 H, m, CH2), 1.72 ꢀ 1.91 (6 H, m,
13
CH2) ppm; C NMR (126 MHz, CDCl3)
δ 157.7, 146.5, 134.3, 129.3, 128.4, 126.9, 126.1,
113.8, 58.5, 55.3, 54.5, 42.8, 33.6, 33.0, 29.1 ppm; m/z (ESI) 310 (M+H+, 100%).
4-Phenyl-1-(6-(trimethylsilyl)hex-5-yn-1-yl)piperidine 49. 4ꢀPhenylꢀ1ꢀ(6ꢀ(trimethylsilyl)hexꢀ
5ꢀynꢀ1ꢀyl)piperidine was synthesised via the general method from 4ꢀphenylpiperidine (161
mg, 1.00 mmol), 6ꢀ(trimethylsilyl)hexꢀ5ꢀynꢀ1ꢀol (332 mg, 2.00 mmol), tricarbonyl(1,3ꢀ
di(trimethylsilyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀone)iron (42.0 mg, 0.100 mmol) and
trimethylamine Nꢀoxide (15.0 mg, 0.2 mmol). Purification via column chromatography eluted
with 0ꢀ60% ethyl acetate in pentane gave 4ꢀphenylꢀ1ꢀ(6ꢀ(trimethylsilyl)hexꢀ5ꢀynꢀ1ꢀ
yl)piperidine as a colourless oil (232 mg, 0.741 mmol, 74.1%). HRMS (EI) m/z: [M + H]+
Calcd for C20H32NSi 314.2299; Found 314.2297;
CDCl3) 7.15 ꢀ 7.34 (5 H, m, Ar ), 3.05 (2 H, d,
11.1, 5.8 Hz, PhCH), 2.35 ꢀ 2.41 (2 H, m, CH2), 2.26 (2 H, t,
ν
max 2935, 2864 cmꢀ1; 1H NMR (500 MHz,
δ
H
J
=11.6 Hz, NCH2), 2.49 (1 H, ddd, =22.1,
J
J
=7.0 Hz, NCH2), 2.02 (2 H, td,
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J
=11.2, 3.4 Hz, CH2NCH2), 1.73 ꢀ 1.90 (4 H, m, CH2), 1.48 ꢀ 1.71 (4 H, m, CH2CH2 in
chain), 0.15 (9 H, s, Si(CH3)3) ppm; 13C NMR (126 MHz, CDCl3)
δ 146.3, 128.2, 126.7,
6
7
8
9
125.9, 107.2, 84.4, 58.4, 54.2, 42.6, 33.3, 26.6, 26.0, 19.7, 0.0 ppm; m/z (ESI) 314 (M+H,
100%).
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1-Cyclopentyl-4-phenylpiperidine 50. 1ꢀCyclopentylꢀ4ꢀphenylpiperidine was synthesised
through the general procedure using 4ꢀphenylpiperidine (161 mg, 1.00 mmol), cyclopentanol
(182 µL, 172 mg, 2.00 mmol), tricarbonyl(1,3ꢀdi(trimethylsilyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ
2ꢀone)iron (42.0 mg, 0.100 mmol) and trimethylamine Nꢀoxide (15.0 mg, 0.200 mmol). 1ꢀ
Cyclohexylꢀ4ꢀphenylpiperidine was isolated via column chromatography eluted with 0ꢀ60%
ethyl acetate in pentane as a colourless oil (207 mg, 0.904 mmol, 90.4%). HRMS (ESIꢀTOF)
1
m/z: [M + H]+ Calcd for C16H24N 230.1903; Found 230.1905; νmax 2954, 2867 cmꢀ1; H
NMR (500 MHz, CDCl3)
2.36 ꢀ 2.60 (2 H, m, C HNC
ꢀ 1.76 (2 H, m, C 2), 1.51 ꢀ 1.63 (2 H, m, C
146.5, 128.4, 126.9, 126.0, 67.8, 53.4, 42.8, 33.5, 30.6, 24.2 ppm; m/z
δ
6.95 ꢀ 7.65 (5 H, m, Ar
H), 1.97 ꢀ 2.10 (2 H, m, C
2), 1.36 ꢀ 1.50 (2 H, m, C
H
), 3.16 (2 H, d,
J
=11.8 Hz, CH
H
NCH
H),
H
H
H2), 1.76 ꢀ 1.96 (6 H, m, C
H2), 1.63
13
H
H
H2) ppm; C NMR
(126 MHz, CDCl3)
230 (M+H, 100%).
δ
1-Cyclohexyl-4-phenylpiperidine 51. 1ꢀCyclohexylꢀ4ꢀphenylpiperidine was synthesised via
the general procedure using 4ꢀphenylpiperidine (161 mg, 1.00 mmol), cyclohexanol (210 µL,
200 mg, 2.00 mmol), tricarbonyl(1,3ꢀdi(trimethylsilyl)ꢀ4,5,6,7ꢀtetrahydroꢀ2Hꢀindenꢀ2ꢀ
one)iron (42.0 mg, 0.100 mmol) and trimethylamine Nꢀoxide (15.0 mg, 0.200 mmol). 1ꢀ
Cyclohexylꢀ4ꢀphenylpiperidine was isolated via column chromatography eluted with 0ꢀ60%
ethyl acetate in pentane as a colourless oil (228 mg, 0.938 mmol, 93.8%). HRMS (ESIꢀTOF)
1
m/z: [M + H]+ Calcd for C17H26N 244.2060; Found 244.2060; ;νmax 2928, 2798 cmꢀ1; H
NMR (500 MHz, CDCl3)
2.47 (1 H, tt, =12.0, 3.9 Hz, C
H, m, C 2), 1.64 (1 H, d,
CH
δ
7.13 ꢀ 7.38 (5 H, m, Ar
H
), 3.03 (2 H, d,
(CH2)2), 2.32 (3 H, td, =11.5, 2.2 Hz, C
), 1.19 ꢀ 1.33 (4 H, m, C 2), 1.00 ꢀ 1.18 (1 H, m,
146.7, 128.4, 126.9, 126.0, 64.1, 49.9, 43.3, 34.1,
J
=11.4 Hz, CH
HNCHH),
J
H
J
H
2), 1.70 ꢀ 2.01 (8
H
J
=12.2 Hz, NC
H
H
H
) ppm; 13C NMR (126 MHz, CDCl3)
δ
28.9, 26.5, 26.2 ppm; m/z 244 (M+H, 100%).
1-Cycloheptyl-4-phenylpiperidine 52. 1ꢀCycloheptylꢀ4ꢀphenylpiperidine was synthesised via
the general procedure using 1ꢀphenylpiperidine (161 mg, 1.00 mmol), cycloheptanol (240 µL,
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