A cascade process for the synthesis of: Ortho -formyl allyl aryl ethers and 2 H -chromen-2-ol derivatives from arynes via trapping of o -quinone methide with an activated alkene

Article abstract of DOI:10.1039/c8ob02507j

A transition-metal free synthetic strategy has been developed for the direct synthesis of ortho-formyl substituted allyl aryl ethers via a cascade three-component coupling of arynes, activated alkene and N,N-dimethylformamide. The reaction proceeds via C-

Full text of DOI:10.1039/c8ob02507j

Organic &
Biomolecular Chemistry
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A cascade process for the synthesis of ortho-
formyl allyl aryl ethers and 2H-chromen-2-ol
derivatives from arynes via trapping of o-quinone
methide with an activated alkene†
a,b
Cite this: Org. Biomol. Chem., 2019,
17, 333
Abhilash Sharmaa,b and Pranjal Gogoi
*
A transition-metal free synthetic strategy has been developed for the direct synthesis of ortho-formyl
substituted allyl aryl ethers via a cascade three-component coupling of arynes, activated alkene and N,N-
dimethylformamide. The reaction proceeds via C–O and C–C bond cleavage as well as C–C and two
new C–O bond formations in a single reaction vessel. The methodology provides a good yield of ortho-
formyl substituted allyl aryl ethers. Moreover, the synthetic strategy has been utilized for the one-pot syn-
thesis of 2H-chromen-2-ol derivatives.
Received 10th October 2018,
Accepted 7th December 2018
DOI: 10.1039/c8ob02507j
rsc.li/obc
Arynes are highly reactive transient intermediates and have [2 + 2] cycloaddition for the synthesis of benzocyclobutenes as
emerged as potent synthons for exploring the new frontiers in relatively stable products, which could be used for the rapid
organic synthesis.1 This reactive intermediate, particularly construction of nitrogen heterocycles.5 On the other hand,
Kobayashi’s protocol for using o-silyl aryl triflate2 as a versatile aryne insertion into the sigma bond6 takes place when the
precursor, is widely used for the development of new-aryne nucleophile and the electrophile belong to the same molecule.
based reactions for the atom-economical synthesis of various In this regard, the Yoshida group pioneered a reaction of aryne
synthetic compounds and natural products.3 Additionally, and β-dicarbonyl compounds which involves aryne insertion
arynes have been used for the synthesis of ortho-disubstituted into the methylene-carbonyl σ-bond to produce the corres-
arenes via multicomponent reactions1c and dipolar cycloaddi- ponding ortho-disubstituted product.3a This synthetic strategy
tion.1f Recently, aryne-based sequential reactions have been provides a powerful and useful tool for the rapid build-up of
utilized for the installation of important functional groups complex molecules in a highly atom-economical manner.
through the formation of carbon–carbon and carbon–hetero- Varieties of amine-containing ortho-disubstituted arenes7 have
atom bonds into adjacent positions of the aromatic skeleton been synthesized via aryne insertion into an amide, arylphos-
for the synthesis of 1,2-difunctionalized arenes in a straight- phoryl amide, and nitrogen-halide bonds or the nucleophilic
forward manner. This synthetic strategy for the one-pot syn- attack of amines on arynes. In addition to these, the insertion
thesis of ortho-disubstituted arenes has been studied exten- of arynes into P–O bonds for the synthesis of ortho-hydroxy
sively with or without a transition-metal catalyst.4 However, substituted arylphosphine oxides,8 aryne insertion into the I–I
most effort has been focused on the transition-metal-free reac- bond for the synthesis of o-diiodoarenes,9 and aryne double
tions which avoid expensive metal-catalysts, ligands and harsh bond insertion/nucleophilic addition with vinylogous amides
reaction conditions.
and carbodiimides10 have been reported.
Synthetic strategies for the direct ortho-functionalization of
Regarding the synthesis of ortho-disubstituted arenes via a
arenes with two versatile functional groups via aryne insertion transition-metal-free three-component coupling reaction, sol-
into a σ-bond and π-bond have gained priority over others. vents such as THF,11 DMSO12 and DMF13 play a dual role as
Regarding the aryne insertion into a CvC bond, Suzuki and the reaction media and reactant. In this regard, the solvent
co-workers have developed a highly stereoselective tandem THF has been used for the synthesis of functionalized bromo-
arenes. Whereas DMSO has been used for the synthesis of
aryl-thioethers via aryne insertion into the SvO bond of
aApplied Organic Chemistry Group, Chemical Science and Technology Division,
DMSO.12a The aryne insertion into the π-bond of DMF pro-
CSIR-North East Institute of Science and Technology, AssamJorhat 785006, India.
ceeds via an interesting reactive intermediate o-quinone
E-mail: gogoipranj@yahoo.co.uk
methide which subsequently reacts with suitable electrophiles
for the synthesis of ortho-functionalized arenes (Fig. 1). Several
synthetic strategies have been developed for the synthesis of
bAcademy of Scientific and Innovative Research (AcSIR), CSIR-NEIST Campus, India
†Electronic supplementary information (ESI) available: Copies of 1H and 13C
NMR and HRMS spectra of all products. See DOI: 10.1039/c8ob02507j
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use of transition-metal and strong bases or Lewis acids for the
introduction of an aldehyde functionality into an aromatic
ring by conventional methods.17
Our experiments were started with optimization studies by
considering
a common aryne precursor 2-(trimethylsilyl)
phenyl trifluoromethanesulfonate 1a (0.5 mmol), activated
alkene methyl-2-(bromomethyl)acrylate 2a (0.75 mmol) and a
well-established fluoride source CsF (1.5 mmol) in DMF
(2 mL) at room temperature for 0.5 h. Under these reaction
conditions, the desired product 3aa was obtained in 68% yield
(Table 1, entry 1). To improve the yield of 3aa, some other flu-
oride sources were also screened (Table 1, entries 2 and 3).
However, no significant enhancement of yield was observed.
Additionally, KF along with 18-crown-6 (1 equiv.) were used as
additives for the synthesis of 3aa. Under these reaction con-
ditions, the desired product 3aa was isolated in 60% yield
(Table 1, entry 4). From these optimization studies, CsF was
found to be a suitable fluoride source for our cascade reaction.
After optimizing our fluoride source, few more experiments
were performed by changing the amount of CsF and the reac-
tion time (Table 1, entries 5–7). To our delight, an improve-
ment of yield (75%) was observed when the reaction was per-
formed using 4 equivalents of CsF for 1 h (Table 1, entry 7),
which were considered as the optimized reaction conditions
for our generalization. In addition to these optimization
studies, we also investigated the solvent effect by using a
mixed solvent (1 : 1; DMF with CH3CN and DMF with THF) for
our cascade process (Table 1, entries 8 and 9). However, no sig-
nificant improvements were observed. As a control experiment,
when the reaction was performed in the absence of a fluoride
source, product 3aa was not observed (Table 1, entry 10).
Fig. 1 Previous and present studies for the synthesis of ortho-di-
substituted arenes via o-quinone methide derived from an aryne and DMF.
functionalized arenes via aryne insertion into the π-bond of
DMF. Miyabe and co-workers developed a general method for
the synthesis of ortho-disubstituted arene via aryne insertion
into the C–heteroatom bond of DMF via the three-component
coupling reaction of aryne, formamide and alkylzinc in a
single reaction vessel.13a Later, they have also developed a mul-
ticomponent reaction via aryne insertion into DMF followed by
trapping with activated methylenes.13b Furthermore, Yoshida
and co-workers have reported the synthesis of diverse cou-
marins via the coupling of ortho-quinone methides generated
from arynes and DMF with active methylene compounds.13c
Recently, Jiang et al. have reported the synthesis of ortho-
formyl diaryl ether by the three-component coupling of aryne,
DMF and diaryliodonium salts.14
From our group, we have also reported the one-pot syn-
thesis of 2-formylarylsulfonate from aryne, aryl sulfonyl chlor-
ide and DMF via o-quinone methide.15 This interesting chem-
istry encouraged us to further investigate the synthetic utility
of o-quinone methide for the synthesis of 1,2-disubstituted
arenes. In continuation of our research on aryne chemistry,16
we came up with an idea to use this highly reactive intermedi-
ate for the direct synthesis of ortho-formyl substituted allyl aryl
ethers and 2-methyl-3-(arylsulfonyl)-2H-chromen-2-ol from
arynes. To the best of our knowledge, there is no such syn-
thetic method/strategy for the direct synthesis of ortho-formyl
substituted allyl aryl ethers and 2H-chromen-2-ol derivatives
from arynes. Here, we used an activated alkene to trap
o-quinone methide derived from an aryne and DMF under
mild conditions for the synthesis of ortho-formyl substituted
allyl aryl ethers (Scheme 1). This synthetic method avoids the
After having the optimized reaction conditions in hand, the
scope of our cascade process was further investigated and the
Table 1 Optimization studiesa
F− Source Additive
Time Temp. Yieldb
Entry (equiv.)
(1 equiv.)
Solvent
(h)
(°C)
(%)
1
2
3
4
5
6
7
8
CsF (3.0)
KF (3.0)
TBAF (3.0)
KF (3.0)
CsF (3.0)
CsF (4.0)
CsF (4.0)
CsF (4.0)
—
—
—
DMF
DMF
DMF
0.5
0.5
0.5
0.5
1.0
0.5
1
rt
rt
rt
rt
rt
rt
rt
rt
68
54
Trace
60
64
70
75
55
18-Crown-6 DMF
—
—
—
—
DMF
DMF
DMF
DMF/CH3CN
(1 : 1)
1
9
CsF (4.0)
—
—
DMF/THF
(1 : 1)
DMF
1
1
rt
rt
69
10
—
ND
a Conditions: o-Silyl aryl triflate 1a (0.5 mmol), methyl-2-(bromo-
methyl)acrylate 2a (0.75 mmol), fluoride source (1.5 to 2 mmol), addi-
tive (0.5 mmol), DMF (2 mL) stirred at rt. b Isolated yield. ND: not
detected.
Scheme 1 Synthesis of o-formyl allyl aryl ether from arynes.
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Table 2 One-pot synthesis of ortho-formyl allyl aryl ether from
benzyne precursorsa
formyl allyl aryl ethers and products 3be and 3ce were syn-
thesized with good yields. Interestingly, when the activated
alkene 2e was treated with o-silyl aryl triflate 1a under the opti-
mized conditions, 2,2′-[(2-methylenepropane-1,3-diyl)bis(oxy)]
dibenzaldehyde bis-3ae was obtained with 42% yield. However,
the yield of bis-3ae could be increased up to 70% by increasing
the amount of alkene 2e (Scheme 2).
Additionally, unsymmetrical benzyne precursors i.e.
4-methyl-2-(trimethylsilyl)phenyl
trifluoromethanesulfonate
1d, 2-methyl-6-(trimethylsilyl)phenyl trifluoromethanesulfo-
nate 1e, 1-(trimethylsilyl)-2-naphthyl trifluoromethanesulfo-
nate 1f and 4-methoxy-2-(trimethylsilyl)phenyl trifluorometha-
nesulfonate 1g were also investigated under our optimized
reaction conditions (Table 3). Benzyne precursors 1d and 1e
provided ortho-formyl allyl aryl ethers 3da/3d′a and 3ec/3e′c as
mixtures of regioisomers. The regioisomers were not separated
into individual isomers and their ratios were calculated from
1H NMR. Furthermore, the unsymmetrical aryne derived from
1f reacted with activated alkenes 2a and 2b to give exclusively
3fa and 3fb in 65% and 67% yield, respectively, with excellent
regioselectivity. However, the unsymmetrical benzyne precur-
sor 1g when treated with methyl 2-(bromomethyl)acrylate 2a
furnished two seperate regioisomers 3ga and 3g′a which were
isolable under flash chromatography and isolated into individ-
ual isomers with 29% and 37% yields, respectively (Table 3).
Interestingly, when the unsymmetrical benzyne precursor
3-methoxy-2-(trimethylsilyl)phenyl trifluoromethanesulfonate
1h was used, a single regioisomer 3ha was formed in 71%
yield with excellent regioselectivity which could be rationalized
by the electronic effect of the –OMe group, favoring the steri-
cally hindered benzoxetene intermediate via aryne insertion
into the CvO of DMF.
a Conditions: o-Silyl aryl triflate
2 (0.75 mmol), fluoride source (2 mmol), DMF (2 mL) stirred at rt
for 1 h.
1 (0.5 mmol), activated alkene
To explore the scope and synthetic utility of our cascade
process, 2-bromoallylsulfone was considered as the activated
alkene for our cascade process. In this regard, (2-bromoallyl-
sulfonyl)benzene 2f derived from 2,3-dibromopropene and
results are presented in Table 2. As shown in Table 2, o-silyl sodium benzenesulfinate was treated with o-silyl aryl triflate 1a
aryl triflate 1a was treated with a variety of activated alkenes, under our optimized reaction conditions. An interesting
leading to our desired ortho-formyl allyl aryl ethers in good cyclized product 2-methyl-3-(phenylsulfonyl)-2H-chromen-2-ol
yields (Table 2, 3aa–3ad).
was isolated and characterized in 67% yield. As shown in
Other symmetrical silyltriflates such as 4,5-dimethoxy-2-(tri- Table 4, other symmetrical as well as unsymmetrical silyltri-
methylsilyl)phenyl trifluoromethanesulfonate 1b and 3-(tri- flates 1b, 1c, and 1h and 5-(trimethylsilyl)benzo[d][1,3]-dioxol-
methylsilyl)-2-naphthyl trifluoromethanesulfonate 1c were also 6-yltrifluoromethane-sulfonate 1i were also examined as aryne
examined as aryne precursors for our cascade process and a precursors to extend the scope of our synthetic utility, and a
series of 2-formyl substituted allyl aryl ethers were synthesized series of 2-methyl-3-(arylsulfonyl)-2H-chromen-2-ol were syn-
in 62–72% yield (Table 2, 3ba–3cc). Additionally, an aryne pre- thesized in 54–67% yields.
cursor bearing an electron-withdrawing group such as 4,5-
difluoro-2-(trimethylsilyl)phenyl trifluoromethanesulfonate 1j
is also used in our cascade process to form the corresponding
2-formyl substituted allyl aryl ether in 66% yield. Under our
optimized reaction conditions, two interesting 2-formyl allyl
aryl ethers 3ad and 3bd having an alkenyl bromide functional-
ity were synthesized, which offer possibilities for further
functionalization as well as the modification of the functional
groups. Moreover, 3-bromo-2-bromomethyl-1-propene 2e was
also used as an activated alkene for the synthesis of ortho- 3-bromo-2-bromomethyl-1-propene.
Scheme 2 Synthesis of bis(oxy)dibenzaldehyde from an aryne and
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Table 3 Synthesis of ortho-formyl allyl aryl ether from unsymmetrical
benzyne precursorsa
Table 4 Synthesis of 2-methyl-3-(arylsulfonyl)-2H-chromen-2-ola
Aryne
precursor (1d–h)
Entry
1
o-Formyl allyl aryl ether (3da–3ha)
2
a Conditions: o-Silyl aryl triflate 1 (0.5 mmol), bromoallyl sulfones 2f–h
(0.75 mmol), fluoride source (2 mmol), DMF (2 mL) stirred at rt for 3 h.
in-generated aryne undergoes insertion into the CvO π-bond
of formamide to form benzoxetene A and its isomer ortho-
quinone methide B. The reactive intermediate B was trapped
by the activated alkene to afford intermediate I. Finally, the
reactive intermediate I leads to ortho-substituted arylaldehyde
3 after the aqueous work-up. Regarding the formation of
2-methyl-3-(arylsulfonyl)-2H-chromen-2-ol from aryne and
2-bromoallylsulfone, it is presumed that in the presence of
CsF, 2-bromoallylsulfone forms sulfonyl allene,18 which under-
goes a conjugate addition with o-quinone methide followed by
an intramolecular nucleophilic addition to form the cyclized
product 4.
3
4
In order to explore the reaction mechanism, a deuterium-
labelling study was performed using DMF-d7 (Scheme 4).
Under the optimized reaction conditions, the corresponding
5
a Conditions: o-Silyl aryl triflate
1 (0.5 mmol), activated alkene
2 (0.75 mmol), fluoride source (2 mmol), DMF (2 mL) stirred at rt for t1 h.
Based on previous reports,13,14,16 a plausible reaction
mechanism for the one-pot synthesis of ortho-formyl allyl aryl
Scheme 3 Plausible reaction mechanism for the synthesis of ortho-
ether is proposed in Scheme 3. As shown in Scheme 3, the formyl allyl aryl ether and 2-methyl-3-(arylsulfonyl)-2H-chromen-2-ol.
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plates (0.2 mm thickness); the chromatograms were visualized
with ultraviolet light (254 nm). Flash column chromatography
was performed with silica gel 60 (100–200 or 200–400 mesh).
HRMS data were recorded via electrospray ionization with a
Q-TOF mass analyzer.
General procedure for the synthesis of o-formyl allyl aryl ether
derivatives
Scheme 4 Isotopic tracer experiment.
An oven-dried round bottom flask (50 mL capacity) equipped
with a magnetic stir bar was evacuated and purged with argon.
o-Silyl aryl triflate (0.5 mmol, 1 equiv.), activated alkene
(0.75 mmol, 1.5 equiv.), CsF (2 mmol, 4 equiv.) and DMF
(2 mL) were added successively at room temperature. The reac-
tion mixture was stirred at room temperature for 1 h. Water
(10 mL) was added to the reaction mixture and the organic
layer was extracted with EtOAc (20 × 2 mL). The combined
organic phases were washed with brine and dried over sodium
sulfate. The solvent was removed and the residue was purified
by column chromatography on silica gel using hexanes/ethyl
acetate as the eluent.
Scheme 5 Independent experiment.
isotope labelled product 3aa-D was isolated in 72% yield.
Complete deuterium incorporation at the hydrogen of the
aldehyde moiety was observed by 1H-NMR analysis, which
reveals that DMF serves as a source of the aldehyde functional-
ity. Reasonably, this observation reveals that our one-pot
sequential reaction proceeded via [2 + 2] cycloaddition of the
aryne with DMF solvent.
Additionally, another independent experiment was per-
formed to know the regioselectivity of nucleophilic substi-
tution. In this regard, gamma-substituted allylic bromide
namely crotyl bromide was used for our cascade process under
the optimized conditions and the 2-formyl substituted allyl
aryl ether 3ai was isolated and characterized (Scheme 5).23
In summary, we have developed a transition-metal-free syn-
thetic strategy for ortho-difunctionalization of an arene via
trapping of an activated alkene by in situ generated ortho-
quinone methide. A series of ortho-formyl allyl aryl ether
derivatives have been synthesized by using our one-pot syn-
thetic strategy in good yields. Remarkably, this synthetic strat-
egy has been accomplished through C–O and C–C bond clea-
vage as well as C–C and two new C–O bond formations in a
single reaction vessel. Additionally, our cascade synthetic strat-
egy has been demonstrated for the one-pot synthesis of
2-methyl-3-(arylsulfonyl)-2H-chromen-2-ol.
Methyl 2-[(2-formylphenoxy)methyl]acrylate (3aa)19
On applying the general experimental procedure using 2-(tri-
methylsilyl)phenyl trifluoromethanesulfonate (0.12 mL;
0.5 mmol, 1 equiv.), methyl-2-(bromomethyl)acrylate (0.09 mL;
0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4 equiv.) in
DMF (2 mL), methyl 2-[(2-formylphenoxy)methyl]acrylate 3aa
was obtained as a light brown gummy product (0.083 g, 75%
yield) after purification by flash chromatography using hexane/
1
EtOAc (9 : 1) as the eluent; H NMR (500 MHz, CDCl3): δ 10.52
(s, 1H), 7.85 (dd, J1 = 1.4 Hz, J2 = 7.7 Hz, 1H), 7.48–7.61 (m,
1H), 7.06 (t, J = 7.5 Hz, 1H), 7.01 (d, J = 8.4 Hz, 1H), 6.46 (s,
1H), 6.06 (s, 1H), 4.87 (s, 2H), 3.82 (s, 3H); 13C NMR (126 MHz,
CDCl3): δ 189.5, 165.6, 160.5, 135.9, 135.1, 128.8, 126.9, 125.1,
121.3, 112.9, 66.6, 52.1; IR (CHCl3): 2923, 2855, 1719, 1687,
1598, 1483, 1456, 1284, 1192, 759, 666 cm−1; HRMS (+ESI)
Calcd for C12H12O4Na [M + Na]+: 243.0633; found: 243.0638.
Ethyl 2-[(2-formylphenoxy)methyl]acrylate (3ab)
On applying the general experimental procedure using 2-(tri-
methylsilyl)phenyl trifluoromethanesulfonate (0.12 mL;
0.5 mmol, 1 equiv.), ethyl-2-(bromomethyl)acrylate (0.10 mL;
0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4 equiv.) in
DMF (2 mL), ethyl 2-[(2-formylphenoxy)methyl]acrylate 3ab
was obtained as a light yellow gummy product (0.078 g, 66%
yield) after purification by flash chromatography using hexane/
Experimental section
General
1
EtOAc (9 : 1) as the eluent; H NMR (500 MHz, CDCl3): δ 10.52
(s, 1H), 7.84 (dd, J1 = 1.7 Hz, J2 = 7.7 Hz, 1H), 7.45–7.60
All reactions involving oxygen- or moisture-sensitive com- (m, 1H), 7.05 (t, J = 7.5 Hz, 1H), 7.01 (d, J = 8.4 Hz, 1H), 6.45 (s,
pounds were carried out under an argon atmosphere using 1H), 6.02 (s, 1H), 4.87 (s, 2H), 4.27 (q, J = 7.1 Hz, 2H), 1.32 (t,
oven-dried or flame-dried glassware. All other solvents and J = 7.1 Hz, 3H); 13C NMR (126 MHz, CDCl3): δ 189.4, 165.1,
reagents were purified according to standard procedures or 160.4, 135.8, 135.3, 128.6, 126.6, 125.0, 121.1, 112.8, 66.6, 61.0,
were used as received from TCI, Aldrich, Merck and 14.1; IR (CHCl3): 2922, 2903, 1714, 1687, 1483, 1456, 1177,
Spectrochem. The reactions were monitored by thin-layer 759, 665 cm−1; HRMS (+ESI) Calcd for C13H14O4Na [M + Na]+:
chromatography (TLC) using aluminium-backed silica gel 257.0790; found: 257.0792.
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2-[(2-Methylallyl)oxy]benzaldehyde (3ac)20
(0.146 mL; 0.5 mmol, 1 equiv.), ethyl 2-(bromomethyl)acrylate
(0.10 mL; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4
equiv.) in DMF (2 mL), ethyl 2-[(2-formyl-4,5-dimethoxy-
phenoxy)methyl]acrylate 3bb was obtained as a light brown
gummy product (0.095 g, 64% yield) after purification by flash
chromatography using hexane/EtOAc (4 : 1) as the eluent;
1H NMR (500 MHz, CDCl3): δ 10.36 (s, 1H), 7.33 (s, 1H), 6.54
(s, 1H), 6.45 (s, 1H), 6.04 (s, 1H), 4.84 (s, 2H), 4.28 (q, J = 7.1
Hz, 2H), 3.95 (s, 3H), 3.88 (s, 3H), 1.33 (t, J = 7.1 Hz, 3H); 13C
NMR (126 MHz, CDCl3): δ 187.8, 165.3, 157.3, 155.7, 144.1,
135.6, 126.9, 117.9, 108.9, 97.6, 67.7, 61.2, 56.3, 56.2, 14.2; IR
(CHCl3): 2976, 2935, 1670, 1606, 1514, 1411, 1277, 1220, 757,
665 cm−1; HRMS (+ESI) Calcd for C15H19O6 [M + H]+:
295.1182; found: 295.1181.
On applying the general experimental procedure using 2-(tri-
methylsilyl)phenyl trifluoromethanesulfonate (0.12 mL;
0.5 mmol, 1 equiv.), 3-bromo-2-methylpropene (0.075 mL;
0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4 equiv.) in
DMF (2 mL), 2-[(2-methylallyl)oxy]benzaldehyde 3ac was
obtained as a light yellow gummy product (0.065 g, 74% yield)
after purification by flash chromatography using hexane/EtOAc
(9 : 1) as the eluent; 1H NMR (500 MHz, CDCl3): δ 10.54 (s, 1H),
7.84 (m, 1H), 7.42–7.63 (m, 1H), 7.02 (t, J = 7.5 Hz, 1H), 6.97
(d, J = 8.4 Hz, 1H), 5.12 (s, 1H), 5.03 (s, 1H), 4.54 (s, 2H), 1.85
(s, 3H); 13C NMR (126 MHz, CDCl3): δ 189.7, 161.0, 139.9,
135.8, 128.3, 124.9, 120.7, 113.2, 112.6, 71.9, 19.4; IR (CHCl3):
2925, 2858, 1690, 1483, 1454, 1283, 1220, 758, 649 cm−1
;
HRMS (+ESI) Calcd for C11H13O2 [M + H]+: 177.0916; found:
4,5-Dimethoxy-2-[(2-methylallyl)oxy]benzaldehyde (3bc)
177.0919.
On applying the general experimental procedure using
2-[(2-Bromoallyl)oxy]benzaldehyde (3ad)21
4,5-dimethoxy-2-(trimethylsilyl)
trifluoromethanesulfonate
(0.146 mL; 0.5 mmol, 1 equiv.), 3-bromo-2-methylpropene
(0.075 mL; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol,
4 equiv.) in DMF (2 mL), 4,5-dimethoxy-2-[(2-methylallyl)oxy]
benzaldehyde 3bc was obtained as a yellow gummy product
(0.084 g, 71% yield) after purification by flash chromatography
using hexane/EtOAc (4 : 1) as the eluent; 1H NMR (500 MHz,
CDCl3): δ 10.38 (s, 1H), 7.32 (s, 1H), 6.51 (s, 1H), 5.14 (s, 1H),
5.05 (s, 1H), 4.54 (s, 2H), 3.94 (s, 3H), 3.88 (s, 3H), 1.86 (s, 3H);
13C NMR (126 MHz, CDCl3): δ 187.9, 157.8, 155.6, 143.6, 140.3,
117.6, 113.4, 108.6, 97.2, 73.0, 56.1, 19.4 (one peak is missing
due to overlapping); IR (CHCl3): 2925, 2850, 1667, 1606, 1513,
1452, 1276, 1219, 756, 665 cm−1; HRMS (+ESI) Calcd for
C13H17O4 [M + H]+: 237.1127; found: 237.1134.
On applying the general experimental procedure using 2-(tri-
methylsilyl)phenyl trifluoromethanesulfonate (0.12 mL;
0.5 mmol,
1
equiv.), 2,3-dibromopropene (0.07 mL;
0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4 equiv.) in
DMF (2 mL), 2-[(2-bromoallyl)oxy]benzaldehyde 3ad was
obtained as a colourless oil (0.063 g, 52% yield) after purifi-
cation by flash chromatography using hexane/EtOAc (9 : 1) as
the eluent; 1H NMR (500 MHz, CDCl3): δ 10.55 (s, 1H), 7.86
(dd, J1 = 1.8 Hz, J2 = 7.7 Hz, 1H), 7.51–7.57 (m, 1H), 7.08 (t, J =
7.5 Hz, 1H), 6.95 (d, J = 8.4 Hz, 1H), 5.95–6.07 (m, 1H),
5.66–5.80 (m, 1H), 4.76 (s, 2H); 13C NMR (126 MHz, CDCl3):
δ 189.4, 159.9, 135.8, 128.7, 126.1, 125.2, 121.7, 118.6, 113.0,
71.9; IR (CHCl3): 2919, 2851, 1684, 1599, 1481, 1458, 1287,
1237, 758, 665 cm−1; HRMS (+ESI) Calcd for C10H10BrO2 [M +
H]+: 240.9864; found: 240.9855.
2-[(2-Bromoallyl)oxy]-4,5-dimethoxybenzaldehyde (3bd)
On applying the general experimental procedure using
4,5-dimethoxy-2-(trimethylsilyl)
trifluoromethanesulfonate
Methyl 2-[(2-formyl-4,5-dimethoxyphenoxy)methyl]acrylate
(3ba)
(0.146 mL; 0.5 mmol, 1 equiv.), 2,3-dibromopropene (0.07 mL;
0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4 equiv.) in
DMF (2 mL), 2-[(2-bromoallyl)oxy]-4,5-dimethoxybenzaldehyde
3bd was obtained as a colourless oil (0.108 g, 72% yield) after
purification by flash chromatography using hexane/EtOAc
(4 : 1) as the eluent; 1H NMR (500 MHz, CDCl3): δ 10.39 (s, 1H),
7.33 (s, 1H), 6.45 (s, 1H), 6.04 (d, J = 1.6 Hz, 1H), 5.74 (d, J =
1.2 Hz, 1H), 4.73 (s, 2H), 3.94 (s, 3H), 3.87 (s, 3H); 13C NMR
(126 MHz, CDCl3): δ 187.8, 156.5, 155.5, 144.3, 126.3, 118.9,
118.0, 108.8, 97.7, 73.1, 56.2, 56.1; IR (CHCl3): 2920, 2855,
1660, 1607, 1520, 1450, 1268, 1220, 759, 666 cm−1; HRMS
(+ESI) Calcd for C12H14BrO4 [M + H]+: 301.0075; found:
301.0076.
On applying the general experimental procedure using 4,5-
dimethoxy-2-(trimethylsilyl)
trifluoromethanesulfonate
(0.146 mL; 0.5 mmol, 1 equiv.), methyl 2-(bromomethyl)acry-
late (0.09 mL; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g;
2 mmol, 4 equiv.) in DMF (2 mL), methyl 2-[(2-formyl-4,5-
dimethoxyphenoxy)methyl]acrylate 3ba was obtained as a
yellow gummy product (0.087 g, 62% yield) after purification
by flash chromatography using hexane/EtOAc (4 : 1) as the
eluent; 1H NMR (500 MHz, CDCl3): δ 10.36 (s, 1H), 7.33 (s,
1H), 6.54 (s, 1H), 6.46 (brs, 1H), 6.06 (brs, 1H), 4.84 (brs, 2H),
3.96 (s, 3H), 3.88 (s, 3H), 3.82 (s, 3H); 13C NMR (126 MHz,
CDCl3): δ 187.7, 165.7, 157.2, 155.7, 144.1, 135.2, 127.3, 117.8,
108.9, 97.5, 67.5, 56.3, 56.1, 52.2; IR (CHCl3): 2917, 2850, 1663,
1605, 1513, 1410, 1275, 1218, 773, 665 cm−1; HRMS (+ESI)
Calcd for C14H16O6Na [M + Na]+: 303.0845; found: 303.0848.
Methyl 2-[{(3-formylnaphthalen-2-yl)oxy}methyl]acrylate (3ca)
On applying the general experimental procedure using 3-(tri-
methylsilyl)-2-naphthyl-trifluoromethanesulfonate (0.14 mL;
0.5 mmol, 1 equiv.), methyl 2-(bromomethyl)acrylate (0.09 mL;
0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4 equiv.) in
Ethyl-2-[(2-formyl-4,5-dimethoxyphenoxy)methyl]acrylate (3bb)
On applying the general experimental procedure using DMF (2 mL), methyl 2-[{(3-formylnaphthalen-2-yl)oxy}methyl]
4,5-dimethoxy-2-(trimethylsilyl)
trifluoromethanesulfonate acrylate 3ca was obtained as a yellow gummy product (0.084 g,
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62% yield) after purification by flash chromatography using chromatography using hexane/EtOAc (9 : 1) as the eluent; 1H
1
hexane/EtOAc (9 : 1) as the eluent; H NMR (500 MHz, CDCl3): NMR (500 MHz, CDCl3): δ 10.48 (d, J = 0.7 Hz, 2H), 7.84 (dd,
δ 10.95 (s, 1H), 9.27 (d, J = 8.7 Hz, 1H), 8.06 (d, J = 9.1 Hz, 1H), J1 = 1.8 Hz, J2 = 7.7 Hz, 2H), 7.48–7.59 (m, 2H), 6.99–7.09 (m,
7.78 (d, J = 8.1 Hz, 1H), 7.63 (m, 1H), 7.44 (t, J = 7.5 Hz, 1H), 4H), 5.52 (brs, 2H), 4.79 (s, 4H); 13C NMR (126 MHz, CDCl3):
7.29 (d, J = 9.1 Hz, 1H), 6.48 (s, 1H), 6.06 (s, 1H), 5.01 (s, 2H), δ 189.2, 160.4, 138.8, 135.8, 128.8, 124.9, 121.2, 116.9, 112.6,
3.84 (s, 3H); 13C NMR (126 MHz, CDCl3): δ 191.7, 165.6, 162.6, 68.8; IR (CHCl3): 2923, 2852, 1683, 1598, 1483, 1455, 1286,
137.5, 135.2, 131.5, 129.9, 128.8, 128.2, 127.4, 125.1, 124.9, 1235, 757, 664 cm−1; HRMS (+ESI) Calcd for C18H16O4Na
117.3, 113.7, 67.8, 52.2; IR (CHCl3): 2921, 2848, 1671, 1590, [M + Na]+: 319.0946; found: 319.0941.
1509, 1435, 1268, 1243, 773, 665 cm−1; HRMS (+ESI) Calcd for
2-[(2-(Bromomethyl)allyl)oxy]-4,5-dimethoxybenzaldehyde
(3be)
C16H14O4Na [M + Na]+: 293.0790; found: 293.0794.
Ethyl 2-[{(3-formylnaphthalen-2-yl)oxy}methyl]acrylate (3cb)
On applying the general experimental procedure using 4,5-
On applying the general experimental procedure using 3-(tri- dimethoxy-2-(trimethylsilyl)
trifluoromethanesulfonate
methylsilyl)-2-naphthyl-trifluoromethanesulfonate (0.14 mL; (0.146 mL; 0.5 mmol, 1 equiv.), 3-bromo-2-bromomethyl-1-
0.5 mmol, 1 equiv.), ethyl 2-(bromomethyl)acrylate (0.10 mL; propene (0.086 mL; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g;
0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4 equiv.) in 2 mmol, 4 equiv.) in DMF (2 mL), 2-[(2-(bromomethyl)allyl)
DMF (2 mL), ethyl 2-[{(3-formylnaphthalen-2-yl)oxy}methyl] oxy]-4,5-dimethoxybenzaldehyde 3be was obtained as a light
acrylate 3cb was obtained as a light yellow gummy product brown gummy product (0.098 g, 62% yield) after purification
(0.090 g, 63% yield) after purification by flash chromatography by flash chromatography using hexane/EtOAc (4 : 1) as the
using hexane/EtOAc (9 : 1) as the eluent; 1H NMR (500 MHz, eluent; 1H NMR (500 MHz, CDCl3): δ 10.36 (s, 1H), 7.32 (s,
CDCl3): δ 10.61 (s, 1H), 8.37 (s, 1H), 7.88 (d, J = 8.2 Hz, 1H), 1H), 6.56 (s, 1H), 5.47 (s, 1H), 5.38 (s, 1H), 4.77 (s, 2H), 4.11 (s,
7.74 (d, J = 8.3 Hz, 1H), 7.54 (t, J = 7.6 Hz, 1H), 7.39 (t, J = 7.5 2H), 3.95 (s, 3H), 3.87 (s, 3H); 13C NMR (126 MHz, CDCl3):
Hz, 1H), 7.23 (s, 1H), 6.48 (d, J = 0.9 Hz, 1H), 6.10 (d, J = 0.9 δ 187.7, 157.3, 155.7, 143.9, 140.3, 118.1, 117.7, 108.8, 97.3,
Hz, 1H), 4.96 (s, 2H), 4.31 (q, J = 7.1 Hz, 2H), 1.35 (t, J = 7.1 Hz, 69.3, 56.4, 56.2, 32.5; IR (CHCl3): 2925, 2852, 1665, 1605, 1513,
3H); 13C NMR (126 MHz, CDCl3): δ 189.8, 165.3, 156.1, 137.4, 1450, 1276, 1219, 756, 666 cm−1; HRMS (+ESI) Calcd for
135.4, 131.3, 129.8, 129.3, 127.9, 126.7, 126.5, 125.6, 124.9, C13H16BrO4 [M + H]+: 315.0232; found: 315.0237.
107.7, 66.5, 61.1, 14.2; IR (CHCl3): 2928, 2870, 1690, 1625,
3-[((2-Bromomethyl)allyl)oxy]-2-naphthaldehyde (3ce)
1598, 1449, 1338, 1309, 1153, 772, 666 cm−1; HRMS (+ESI)
Calcd for C17H16O4Na [M + Na]+: 307.0946; found: 307.0948.
On applying the general experimental procedure using 3-(tri-
methylsilyl)-2-naphthyl-trifluoromethanesulfonate (0.14 mL;
3-[(2-Methylallyl)oxy]-2-naphthaldehyde (3cc)
0.5 mmol,
1
equiv.), 3-bromo-2-bromomethyl-1-propene
On applying the general experimental procedure using 3-(tri- (0.086 mL; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol,
methylsilyl)-2-naphthyl-trifluoromethanesulfonate (0.14 mL; 4 equiv.) in DMF (2 mL), 3-[((2-bromomethyl)allyl)oxy]-2-
0.5 mmol, 1 equiv.), 3-bromo-2-methylpropene (0.075 mL; naphthaldehyde 3ce was obtained as a light yellow gummy
0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4 equiv.) in product (0.092 g, 60% yield) after purification by flash chrom-
DMF (2 mL), 3-[(2-methylallyl)oxy]-2-naphthaldehyde 3cc was atography using hexane/EtOAc (9 : 1) as the eluent; 1H NMR
obtained as a yellow gummy product (0.080 g, 71% yield) after (500 MHz, CDCl3): δ 10.61 (s, 1H), 8.38 (s, 1H), 7.89 (d, J = 8.2
purification by flash chromatography using hexane/EtOAc Hz, 1H), 7.74 (d, J = 8.3 Hz, 1H), 7.48–7.61 (m, 1H), 7.37–7.43
(9 : 1) as the eluent; 1H NMR (500 MHz, CDCl3): δ 10.65 (s, 1H), (m, 1H), 7.25 (s, 1H), 5.51 (d, J = 0.6 Hz, 1H), 5.47 (d, J =
8.37 (s, 1H), 7.87 (d, J = 8.2 Hz, 1H), 7.72 (d, J = 8.3 Hz, 1H), 0.5 Hz, 1H), 4.88 (s, 2H), 4.17 (s, 2H); 13C NMR (126 MHz,
7.33–7.57 (m, 2H), 7.19 (s, 1H), 5.20 (s, 1H), 5.07 (s, 1H), 4.64 CDCl3): δ 189.9, 156.2, 140.3, 137.4, 131.2, 129.9, 129.3, 127.9,
(s, 2H), 1.91 (s, 3H); 13C NMR (126 MHz, CDCl3): δ 190.1, 126.7, 125.6, 124.9, 118.2, 107.6, 68.5, 32.6; IR (CHCl3): 2926,
156.6, 140.0, 137.4, 130.6, 129.8, 129.1, 127.7, 126.5, 125.6, 2852, 1687, 1625, 1449, 1247, 1211, 748, 665 cm−1; HRMS
124.6, 113.1, 107.4, 71.9, 19.4; IR (CHCl3): 2918, 2850, 1686, (+ESI) Calcd for C15H14BrO2 [M + H]+: 305.0177; found:
1624, 1597, 1451, 1337, 772, 666 cm−1; HRMS (+ESI) Calcd for 305.0162.
C15H15O2 [M + H]+: 227.1072; found: 227.1072.
Methyl 2-[(4,5-difluoro-2-formylphenoxy)methyl]acrylate (3ja)
2,2′-[(2-Methylenepropane-1,3-diyl)bis(oxy)]dibenzaldehyde
On applying the general experimental procedure using
4,5-difluoro-2-(trimethylsilyl)phenyl trifluoromethanesulfonate
(3ae)22
On applying the general experimental procedure using 2-(tri- (0.12 mL; 0.5 mmol, 1 equiv.), methyl-2-(bromomethyl)acrylate
methylsilyl)phenyl trifluoromethanesulfonate (0.12 mL; (0.09 mL; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol,
0.5 mmol,
1
equiv.), 3-bromo-2-bromomethyl-1-propene 4 equiv.) in DMF (2 mL), methyl 2-[(4,5-difluoro-2-formyl-
(0.172 mL; 1.5 mmol, 3 equiv.), and CsF (0.304 g; 2 mmol, phenoxy)methyl]acrylate 3ja was obtained as a white solid
4 equiv.) in DMF (2 mL), 2,2′-[(2-methylenepropane-1,3-diyl)bis (0.085 g, 66% yield) after purification by flash chromatography
(oxy)]dibenzaldehyde 3ae was obtained as a light yellow using hexane/EtOAc (9 : 1) as the eluent; mp: 151–153 °C; 1H
gummy product (0.104 g, 70% yield) after purification by flash NMR (500 MHz, CDCl3): δ 10.37 (s, 1H), 7.66 (t, J = 9.5 Hz, 1H),
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6.86 (dd, J1 = 5.9 Hz, J2 = 11.5 Hz, 1H), 6.48 (s, 1H), 6.02 (s, 811, 665 cm−1; HRMS (+ESI) Calcd for C14H16O4Na [M + Na]+:
1H), 4.82 (s, 2H), 3.85 (s, 3H); 13C NMR (126 MHz, CDCl3): 271.0946; found: 271.0948.
δ 186.9, 165.3, 157.4 (dd, J1 = 1.5 Hz, J2 = 8.3 Hz), 155.9 (d, J =
4-Methyl-2-[(2-methylallyl)oxy]benzaldehyde and 5-methyl-2-
[(2-methylallyl)oxy]benzaldehyde (3dc) and (3d’c)
14.4 Hz), 153.8 (d, J = 14.5 Hz), 146.3 (d, J = 13.1 Hz), 144.4 (d,
J = 13.1 Hz), 134.4, 127.7, 121.4 (t, J = 3.5 Hz), 116.5 (dd, J1 =
2.8 Hz, J2 = 18.7 Hz), 103.1 (d, J = 21.5 Hz), 67.6, 52.3; IR On applying the general experimental procedure using
(CHCl3): 2922, 2849, 1718, 1677, 1625, 1604, 1436, 1292, 1208, 4-methyl-2-(trimethylsilyl)phenyl trifluoromethanesulphonate
959, 890 cm−1; HRMS (−ESI) Calcd for C12H9F2O4 [M − H]+: (0.13 mL; 0.5 mmol, 1 equiv.), 3-bromo-2-methylpropene
255.0469; found: 255.0470.
(0.075 mL; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol,
4 equiv.) in DMF (2 mL), a mixture of 4-methyl-2-[(2-methyl-
allyl)oxy]benzaldehyde and 5-methyl-2-[(2-methylallyl)oxy]
benzaldehyde (3dc and 3d′c) was obtained as a yellow gummy
product (0.074 g, 78% yield) after purification by flash chrom-
atography using hexane/EtOAc (9 : 1) as the eluent; 1H NMR
(500 MHz, CDCl3): δ 10.51 (s, 1H), 10.48 (s, 1H), 7.72 (d, J =
7.9 Hz, 1H), 7.62 (d, J = 2.0 Hz, 1H), 7.31 (dd, J1 = 2.2 Hz, J2 =
8.3 Hz, 1H), 6.86 (d, J = 8.6 Hz, 1H), 6.82 (d, J = 7.4 Hz, 1H),
6.76 (s, 1H), 4.94–5.19 (m, 4H), 4.51 (s, 2H), 4.50 (s, 2H), 2.38
(s, 3H), 2.29 (s, 3H), 1.85 (s, 3H), 1.84 (s, 3H); 13C NMR
(126 MHz, CDCl3): δ 189.9, 189.3, 161.1, 159.1, 147.3, 140.3,
140.1, 136.5, 130.1, 128.3, 128.2, 124.6, 122.7, 121.8, 113.2,
113.0, 112.8, 72.0, 71.8, 22.3, 20.2, 19.4; IR (CHCl3): 2992,
2859, 1683, 1606, 1497, 1280, 1257, 771, 665 cm−1; HRMS
(+ESI) Calcd for C12H15O2 [M + H]+: 191.1072; found: 191.1074.
Methyl 2-[(2-formyl-5-methylphenoxy)methyl]acrylate and
methyl 2-[(2-formyl-4-methylphenoxy)methyl]acrylate (3da)
and (3d′a)
On applying the general experimental procedure using
4-methyl-2-(trimethylsilyl)phenyl trifluoromethanesulphonate
(0.13 mL; 0.5 mmol, 1 equiv.), methyl 2-(bromomethyl)acrylate
(0.09 mL; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol,
4 equiv.) in DMF (2 mL), a mixture of methyl 2-[(2-formyl-5-
methylphenoxy)methyl]acrylate and methyl 2-[(2-formyl-4-
methylphenoxy)methyl]acrylate (3da and 3d′a) was obtained as
a yellow gummy product (0.086 g, 73% yield) after purification
by flash chromatography using hexane/EtOAc (9 : 1) as the
eluent; 1H NMR (500 MHz, CDCl3): δ 10.48 (s, 1H), 10.43 (s,
1H), 7.73 (d, J = 7.8 Hz, 1H), 7.63 (d, J = 1.7 Hz, 1H), 7.34 (dd,
J1 = 2.1 Hz, J2 = 8.5 Hz, 1H), 6.90 (d, J = 8.5 Hz, 1H), 6.86 (d, J =
7.8 Hz, 1H), 6.80 (s, 1H), 6.45 (s, 1H), 6.44 (s, 1H), 6.05 (s, 1H),
6.03 (s, 1H), 4.84 (s, 2H), 4.83 (s, 2H), 3.82 (s, 3H), 3.81 (s, 3H),
2.39 (s, 3H), 2.31 (s, 3H); 13C NMR (126 MHz, CDCl3): δ 189.6,
189.1, 165.7, 160.5, 158.5, 147.5, 136.6, 135.2, 135.1, 130.7,
128.8, 128.7, 126.9, 126.8, 124.7, 122.8, 122.2, 113.4, 112.9,
66.7, 66.4, 52.1, 52.0, 22.3, 20.2; IR (CHCl3): 2922, 2854, 1686,
1607, 1390, 1259, 1151, 772, 665 cm−1; HRMS (+ESI) Calcd for
C13H14O4Na [M + Na]+: 257.0790; found: 257.0796.
2-[(2-Bromoallyl)oxy]-4-methylbenzaldehyde and 2-[(2-
bromoallyl)oxy]-5-methylbenzaldehyde (3dd) and (3d′d)
On applying the general experimental procedure using
4-methyl-2-(trimethylsilyl)phenyl trifluoromethanesulphonate
(0.13 mL; 0.5 mmol, 1 equiv.), 2,3-dibromopropene (0.07 mL;
0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4 equiv.) in
DMF (2 mL), a mixture of 2-[(2-bromoallyl)oxy]-4-methyl-
benzaldehyde and 2-[(2-bromoallyl)oxy]-5-methylbenzaldehyde
(3dd and 3d′d) was obtained as a colourless oil (0.080 g, 63%
yield) after purification by flash chromatography using hexane/
Ethyl 2-[(2-formyl-5-methylphenoxy)methyl]acrylate and ethyl
2-[(2-formyl-4-methylphenoxy)methyl]acrylate (3db) and (3d′b)
1
EtOAc (9 : 1) as the eluent; H NMR (500 MHz, CDCl3): δ 10.52
(s, 1H), 10.47 (s, 1H), 7.87 (d, J = 7.7 Hz, 1H), 7.66 (d, J = 2.1
On applying the general experimental procedure using Hz, 1H), 7.34 (dd, J1 = 2.2 Hz, J2 = 8.3 Hz, 1H), 6.89 (d, J = 7.9
4-methyl-2-(trimethylsilyl)phenyl trifluoromethanesulphonate Hz, 1H), 6.85 (d, J = 8.5 Hz, 1H), 6.73 (s, 1H), 5.96–6.06 (m,
(0.13 mL; 0.5 mmol, 1 equiv.), ethyl 2-(bromomethyl)acrylate 2H), 5.65–5.75 (m, 2H), 4.74 (m, 4H), 2.40 (s, 3H), 2.32 (s, 3H);
(0.10 mL; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 13C NMR (126 MHz, CDCl3): δ 189.6, 189.0, 159.8, 157.9, 147.3,
4 equiv.) in DMF (2 mL), a mixture of ethyl 2-[(2-formyl-5- 136.4, 131.1, 128.6, 128.5, 126.2, 126.0, 124.7, 122.8, 122.6,
methylphenoxy)methyl]acrylate and ethyl 2-[(2-formyl-4- 118.4, 118.3, 113.4, 112.9, 71.9, 71.7, 22.2, 20.2; IR (CHCl3):
methylphenoxy)methyl]acrylate (3db and 3d′b) was obtained 2923, 2854, 1683, 1607, 1496, 1284, 1257, 771, 666 cm−1
;
as a light yellow gummy product (0.095 g, 76% yield) after HRMS (+ESI) Calcd for C11H12BrO2 [M + H]+: 255.0021; found:
purification by flash chromatography using hexane/EtOAc 255.0020.
(9 : 1) as the eluent; 1H NMR (500 MHz, CDCl3): δ 10.48 (s, 1H),
10.44 (s, 1H), 7.73 (d, J = 7.8 Hz, 1H), 7.63 (d, J = 1.6 Hz, 1H),
Methyl 2-[(2-formyl-3-methylphenoxy)methyl]acrylate and
methyl 2-[(2-formyl-6-methylphenoxy)methyl]acrylate (3ea)
and (3e′a)
7.34 (dd, J1 = 2.4 Hz, J2 = 8.5 Hz, 1H), 6.91 (d, J = 8.5 Hz, 1H),
6.86 (dd, J1 = 0.6 Hz, J2 = 7.9 Hz, 1H), 6.80 (s, 1H), 6.40–6.46
(m, 2H), 5.98–6.06 (m, 2H), 4.80 (m, 4H), 4.21–4.33 (m, 4H), On applying the general experimental procedure using
2.39 (s, 3H), 2.31 (s, 3H), 1.26–1.38 (m, 6H); 13C NMR 2-methyl-6-(trimethylsilyl)phenyl trifluoromethanesulphonate
(126 MHz, CDCl3): δ 189.6, 189.1, 165.2, 160.6, 158.6, 147.5, (0.13 mL; 0.5 mmol, 1 equiv.), methyl 2-(bromomethyl)acrylate
136.6, 135.6, 135.4, 130.7, 128.7, 128.6, 126.6, 126.5, 124.8, (0.09 mL; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol,
122.9, 122.2, 113.4, 113.0, 66.8, 66.5, 61.1, 61.0, 22.3, 20.2, 4 equiv.) in DMF (2 mL), a mixture of methyl 2-[(2-formyl-3-
15.1; IR (CHCl3): 2921, 2848, 1685, 1607, 1497, 1259, 1153, methylphenoxy)methyl]acrylate and methyl 2-[(2-formyl-6-
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methylphenoxy)methyl]acrylate (3ea and 3e′a) was obtained as 129.3, 126.1, 124.3, 124.1, 113.4, 110.1, 79.4, 72.1, 21.5, 19.6,
a yellow gummy product (0.080 g, 68% yield) after purification 19.3, 15.7; IR (CHCl3): 2927, 2859, 1687, 1588, 1471, 1261,
by flash chromatography using hexane/EtOAc (9 : 1) as the 1248, 779, 665 cm−1; HRMS (+ESI) Calcd for C12H15O2
eluent; 1H NMR (500 MHz, CDCl3): δ 10.69 (s, 1H), 10.33 (s, [M + H]+: 191.1072; found: 191.1074.
1H), 7.69 (dd, J1 = 1.7 Hz, J2 = 7.7 Hz, 1H), 7.45 (m, 1H), 7.37 (t,
Methyl 2-[{(1-formylnaphthalen-2-yl)oxy}methyl]acrylate (3fa)
J = 8.0 Hz, 1H), 7.16 (t, J = 7.6 Hz, 1H), 6.86 (d, J = 8.4 Hz, 1H),
6.83 (d, J = 7.6 Hz, 1H), 6.47 (d, J = 0.9 Hz, 1H), 6.44 (d, J = On applying the general experimental procedure using 1-(tri-
1.0 Hz, 1H), 6.12 (d, J = 1.4 Hz, 1H), 6.02 (d, J = 0.9 Hz, 1H), methylsilyl)-2-naphthyltrifluoromethanesulfonate (0.14 mL;
4.83 (t, J = 1.5 Hz, 2H), 4.64 (s, 2H), 3.81 (s, 3H), 3.79 (s, 3H), 0.5 mmol, 1 equiv.), methyl 2-(bromomethyl)acrylate (0.09 mL;
2.57 (s, 3H), 2.33 (s, 3H); 13C NMR (126 MHz, CDCl3): δ 191.9, 0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4 equiv.) in
190.3, 165.7, 161.7, 159.9, 142.2, 137.6, 135.7, 135.2, 134.4, DMF (2 mL), methyl 2-[{(1-formylnaphthalen-2-yl)oxy}methyl]
132.4, 129.4, 127.7, 126.9, 126.5, 124.7, 124.6, 110.3, 73.4, 66.7, acrylate 3fa was obtained as a yellow gummy product (0.088 g,
52.1, 52.0, 21.4, 15.6; IR (CHCl3): 2925, 2855, 1719, 1686, 1588, 65% yield) after purification by flash chromatography using
1
1471, 1438, 1274, 1247, 779, 666 cm−1; HRMS (+ESI) Calcd for hexane/EtOAc (9 : 1) as the eluent; H NMR (500 MHz, CDCl3):
C13H14O4Na [M + Na]+: 257.0790; found: 257.0792.
δ 10.95 (s, 1H), 9.26 (d, J = 8.7 Hz, 1H), 8.06 (d, J = 9.1 Hz, 1H),
7.78 (d, J = 8.1 Hz, 1H), 7.63 (m, 1H), 7.44 (m, 1H), 7.29 (d, J =
9.1 Hz, 1H), 6.48 (d, J = 0.8 Hz, 1H), 6.06 (d, J = 0.7 Hz, 1H),
5.01 (s, 2H), 3.84 (s, 3H); 13C NMR (126 MHz, CDCl3): δ 191.6,
Ethyl 2-[(2-formyl-3-methylphenoxy)methyl]acrylate and ethyl
2-[(2-formyl-6-methylphenoxy)methyl]acrylate (3eb) and (3e′b)
On applying the general experimental procedure using 165.6, 162.6, 137.5, 135.1, 131.4, 129.9, 128.7, 128.1, 127.3,
2-methyl-6-(trimethylsilyl)phenyl trifluoromethanesulphonate 124.9, 124.8, 117.1, 113.6, 67.6, 52.1; IR (CHCl3): 2951, 2877,
(0.13 mL; 0.5 mmol, 1 equiv.), ethyl 2-(bromomethyl)acrylate 1673, 1619, 1602, 1591, 1269, 1245, 775, 666 cm−1; HRMS
(0.10 mL; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, (+ESI) Calcd for C16H15O4 [M + H]+: 271.0970; found: 271.0963.
4 equiv.) in DMF (2 mL), a mixture of ethyl 2-[(2-formyl-3-
Ethyl 2-[{(1-formylnaphthalen-2-yl)oxy}methyl]acrylate (3fb)
methylphenoxy)methyl]acrylate and ethyl 2-[(2-formyl-6-
methylphenoxy)methyl]acrylate (3eb and 3e′b) was obtained as On applying the general experimental procedure using 1-(tri-
a light yellow gummy product (0.092 g, 74% yield) after purifi- methylsilyl)-2-naphthyl trifluoromethanesulfonate (0.14 mL;
cation by flash chromatography using hexane/EtOAc (9 : 1) as 0.5 mmol, 1equiv), ethyl 2-(bromomethyl)acrylate (0.10 mL;
the eluent; 1H NMR (500 MHz, CDCl3): δ 10.69 (s), 10.34 (s), 0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4 equiv.) in
7.69 (dd, J1 = 1.6 Hz, J2 = 7.7 Hz), 7.45 (d, J = 6.6 Hz), 7.37 (t, J = DMF (2 mL), ethyl 2-[{(1-formylnaphthalen-2-yl)oxy}methyl]
8.0 Hz), 7.15 (d, J = 7.6 Hz), 6.86 (d, J = 8.4 Hz), 6.83 (d, J = acrylate 3fb was obtained as a yellow gummy product (0.095 g,
7.6 Hz), 6.46 (d, J = 0.7 Hz), 6.43 (d, J = 1.1 Hz), 6.11 (d, J = 1.4 67% yield) after purification by flash chromatography using
1
Hz), 5.99 (d, J = 0.9 Hz), 4.83 (s), 4.64 (s), 4.19–4.33 (m), 2.57 hexane/EtOAc (9 : 1) as the eluent; H NMR (500 MHz, CDCl3):
(s), 2.33 (s), 1.30 (t, J = 7.4 Hz); 13C NMR (126 MHz, CDCl3): δ 10.95 (s, 1H), 9.26 (dd, J1 = 0.7 Hz, J2 = 8.7 Hz, 1H), 8.05 (d,
δ 191.5, 190.3, 165.3, 165.2, 161.8, 160.0, 142.1, 137.6, 136.1, J = 9.1 Hz, 1H), 7.78 (d, J = 8.0 Hz, 1H), 7.63 (m, 1H), 7.43 (m,
135.4, 134.4, 132.4, 129.4, 127.5, 126.6, 126.5, 124.6, 124.5, 1H), 7.30 (d, J = 9.2 Hz, 1H), 6.47 (d, J = 0.9 Hz, 1H), 6.04 (d, J =
123.6, 110.4, 73.4, 66.8, 61.1, 21.4, 15.6, 14.2, 14.1; IR (CHCl3): 0.9 Hz, 1H), 5.01 (t, J = 1.4 Hz, 2H), 4.29 (q, J = 7.1 Hz, 2H),
2924, 2843, 1719, 1686, 1555, 1472, 772, 665 cm−1; HRMS 1.33 (t, J = 7.1 Hz, 3H); 13C NMR (126 MHz, CDCl3): δ 191.7,
(+ESI) Calcd for C14H16O4Na [M + Na]+: 271.0946; found: 165.2, 162.7, 137.5, 135.5, 131.5, 129.9, 128.8, 128.2, 127.1,
271.0941.
125.0, 124.9, 117.3, 113.8, 67.8, 61.2, 14.2; IR (CHCl3): 2927,
2874, 1675, 1619, 1591, 1509, 1269, 1245, 775, 665 cm−1
;
2-Methyl-6-[(2-methylallyl)oxy]benzaldehyde and 3-methyl-2-
[(2-methylallyl)oxy]benzaldehyde (3ec) and (3e′c)
HRMS (+ESI) Calcd for C17H17O4 [M + H]+: 285.1127; found:
285.1121.
On applying the general experimental procedure using
2-methyl-6-(trimethylsilyl)phenyl trifluoromethanesulphonate
(0.13 mL; 0.5 mmol, 1 equiv.), 3-bromo-2-methylpropene
(0.075 mL; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4
Methyl 2-[(2-formyl-4-methoxyphenoxy)methyl]acrylate (3ga)
and methyl 2-[(2-formyl-5-methoxyphenoxy)methyl]acrylate
(3g′a)
equiv.) in DMF (2 mL), a mixture of 2-methyl-6-[(2-methylallyl) On applying the general experimental procedure using
oxy]benzaldehyde and 3-methyl-2-[(2-methylallyl)oxy]benz- 4-methoxy-2-(trimethylsilyl)phenyl trifluoromethanesulpho-
aldehyde (3ec and 3e′c) was obtained as a yellow gummy nate (0.13 mL; 0.5 mmol, 1 equiv.), methyl 2-(bromomethyl)
product (0.072 g, 76% yield) after purification by flash chrom- acrylate (0.09 mL; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g;
atography using hexane/EtOAc (9 : 1) as the eluent; 1H NMR 2 mmol, 4 equiv.) in DMF (2 mL), methyl 2-[(2-formyl-4-meth-
(500 MHz, CDCl3): δ 10.72 (d, J = 0.5 Hz), 10.36 (d, J = 0.7 Hz), oxyphenoxy)methyl]acrylate 3ga was obtained as a light yellow
7.69 (dd, J1 = 1.3 Hz, J2 = 7.7 Hz), 7.32–7.47 (m), 7.14 (t, J = gummy product (0.037 g, 29% yield), and methyl 2-[(2-formyl-
7.6 Hz), 6.81 (t, J = 8.1 Hz), 4.96–5.20 (m), 4.51 (s), 4.32 (s), 2.57 5-methoxyphenoxy)methyl]acrylate 3g′a as a yellow gummy
(s), 2.34 (s), 1.90 (s), 1.84 (s); 13C NMR (126 MHz, CDCl3): product (0.046 g; 37% yield) and were isolated by flash chrom-
δ 192.2, 190.5, 162.2, 160.6, 141.9, 140.4, 137.5, 134.3, 132.3, atography using hexane/EtOAc (4 : 1) as the eluent:
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For 3ga: 1H NMR (500 MHz, CDCl3): δ 10.47 (s, 1H), 7.33 (d, equiv.) in DMF (2 mL), 5-methoxy-2-[(2-methylallyl)oxy]benz-
J = 3.2 Hz, 1H), 7.12 (dd, J1 = 3.3 Hz, J2 = 9.1 Hz, 1H), 6.96 (d, aldehyde 3gc was obtained as a light yellow gummy product
J = 9.1 Hz, 1H), 6.44 (d, J = 1.0 Hz, 1H), 6.01 (d, J = 1.0 Hz, 1H), (0.030 g, 29% yield) and 4-methoxy-2-[(2-methylallyl)oxy]benz-
4.82 (t, J = 1.4 Hz, 2H), 3.81 (s, 3H), 3.80 (s, 3H); 13C NMR aldehyde 3g′c as a yellow gummy product (0.036 g; 35% yield)
(126 MHz, CDCl3): δ 189.2, 165.6, 155.2, 153.9, 135.2, 126.9, and were isolated by flash chromatography using hexane/
125.3, 123.4, 114.9, 110.3, 67.3, 55.7, 52.0; IR (CHCl3): 2921, EtOAc (4 : 1) as the eluent:
2837, 1676, 1637, 1492, 1277, 1218, 772, 666 cm−1; HRMS
(+ESI) Calcd for C13H14O5Na [M + Na]+: 273.0739; found: J = 3.3 Hz, 1H), 7.10 (dd, J1 = 3.3 Hz, J2 = 9.1 Hz, 1H), 6.93 (d,
273.0733. J = 9.1 Hz, 1H), 5.00–5.11 (m, 2H), 4.49 (s, 2H), 3.79 (s, 3H),
For 3gc: 1H NMR (500 MHz, CDCl3): δ 10.50 (s, 1H), 7.32 (d,
1
For 3g′a: H NMR (500 MHz, CDCl3): δ 10.33 (d, J = 0.7 Hz, 1.83 (s, 3H); 13C NMR (126 MHz, CDCl3): δ 189.5, 155.9, 153.6,
1H), 7.82 (d, J = 8.7 Hz, 1H), 6.57 (m, 1H), 6.47 (d, J = 2.2 Hz, 140.2, 125.2, 123.5, 114.7, 113.1, 110.1, 72.7, 55.7, 19.4; IR
1H), 6.46 (dd, J1 = 1.3 Hz, J2 = 2.3 Hz, 1H), 6.06 (dd, J1 = 1.7 Hz, (CHCl3): 2927, 2864, 1684, 1613, 1492, 1276, 1217, 772,
J2 = 2.6 Hz, 1H), 4.83 (t, J = 1.5 Hz, 2H), 3.86 (s, 3H), 3.82 665 cm−1; HRMS (+ESI) Calcd for C12H15O3 [M + H]+:
(s, 3H); 13C NMR (126 MHz, CDCl3): δ 188.0, 166.1, 165.6, 207.1021;found: 207.1024.
162.2, 134.9, 130.9, 127.0, 119.2, 106.4, 99.0, 66.4, 55.7, 52.1;
For 3g′c: 1H NMR (500 MHz, CDCl3): δ 10.36 (s, 1H), 7.81
IR (CHCl3): 2923, 2851, 1677, 1599, 1439, 1259, 1200, 772, (d, J = 8.7 Hz, 1H), 6.54 (dd, J1 = 2.2 Hz, J2 = 8.7 Hz, 1H), 6.43
666 cm−1; HRMS (+ESI) Calcd for C13H15O5 [M + H]+: (d, J = 2.2 Hz, 1H), 5.12 (s, 1H), 5.03 (s, 1H), 4.51 (s, 2H), 3.85
251.0919; found: 251.0913.
(s, 3H), 1.84 (s, 3H); 13C NMR (126 MHz, CDCl3): δ 188.2,
166.0, 162.8, 139.9, 130.4, 119.2, 113.3, 106.0, 98.9, 72.0, 55.6,
19.3; IR (CHCl3): 2927, 2850, 1678, 1602, 1500, 1297, 1261,
770, 665 cm−1; HRMS (+ESI) Calcd for C12H15O3 [M + H]+:
Ethyl 2-[(2-formyl-4-methoxyphenoxy)methyl]acrylate (3gb) and
ethyl 2-[(2-formyl-5-methoxyphenoxy)methyl]acrylate (3g′b)
On applying the general experimental procedure using 207.1021; found: 207.1024.
4-methoxy-2-(trimethylsilyl)phenyl trifluoromethanesulpho-
nate (0.13 mL; 0.5 mmol, 1 equiv.), ethyl 2-(bromomethyl)acry-
late (0.10 mL; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g; On applying the general experimental procedure using
2 mmol, 4 equiv.) in DMF (2 mL), ethyl 2-[(2-formyl-4-methoxy- 3-methoxy-2-(trimethylsilyl)phenyl trifluoromethanesulpho-
Methyl 2-[(2-formyl-3-methoxyphenoxy)methyl]acrylate (3ha)
phenoxy)methyl]acrylate 3gb was obtained as a light yellow nate (0.13 mL; 0.5 mmol, 1 equiv.), methyl 2-(bromomethyl)
gummy product (0.038 g, 29% yield) and ethyl 2-[(2-formyl-5- acrylate (0.09 mL; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g;
methoxyphenoxy)methyl]acrylate 3g′b as a yellow gummy 2 mmol, 4 equiv.) in DMF (2 mL), methyl 2-[(2-formyl-3-meth-
product (0.052 g; 39% yield) and were isolated by flash chrom- oxyphenoxy)methyl]acrylate 3ha was obtained as a light yellow
atography using hexane/EtOAc (4 : 1) as the eluent:
gummy product (0.089 g, 71% yield) after purification by flash
For 3gb: 1H NMR (500 MHz, CDCl3): δ 10.47 (s, 1H), 7.32 (d, chromatography using hexane/EtOAc (4 : 1) as the eluent; 1H
J = 3.2 Hz, 1H), 7.11 (dd, J1 = 3.3 Hz, J2 = 9.1 Hz, 1H), 6.97 (d, NMR (500 MHz, CDCl3): δ 10.55 (s, 1H), 7.44 (t, J = 8.5 Hz, 1H),
J = 9.1 Hz, 1H), 6.42 (d, J = 0.8 Hz, 1H), 5.98 (s, 1H), 4.81 (s, 6.61 (s, 1H), 6.59 (s, 1H), 6.45 (m, 1H), 6.26 (m, 1H), 4.81 (t, J =
2H), 4.62 (q, J = 7.1 Hz, 2H), 3.79 (s, 3H), 1.31 (t, J = 7.1 Hz, 1.8 Hz, 2H), 3.90 (s, 3H), 3.80 (s, 3H); 13C NMR (126 MHz,
3H); 13C NMR (126 MHz, CDCl3): δ 189.3, 165.2, 155.3, 153.9, CDCl3): δ 189.1, 165.7, 162.3, 160.5, 135.9, 134.8, 126.9, 114.5,
135.6, 126.7, 125.4, 123.4, 114.9, 110.4, 67.5, 61.1, 55.7, 14.1; 104.9, 104.3, 66.7, 56.1, 52.0; IR (CHCl3): 2922, 2843, 1683,
IR (CHCl3): 2927, 2854, 1686, 1555, 1494, 1277, 1217, 772, 1596, 1474, 1256, 773, 665 cm−1; HRMS (+ESI) Calcd for
665 cm−1; HRMS (+ESI) Calcd for C14H16O5Na [M + Na]+: C13H14O5Na [M + Na]+: 273.0739; found: 273.0740.
287.0895; found: 287.0898.
1
Methyl 2-[(2-(formyl-d)phenoxy)methyl]acrylate {3aa(D)}
For 3g’b: H NMR (500 MHz, CDCl3): δ 10.33 (d, J = 1.0 Hz,
1H), 7.82 (dd, J1 = 1.7 Hz, J2 = 8.7 Hz, 1H), 6.57 (d, J = 8.7 Hz, On applying the general experimental procedure using 2-(tri-
1H), 6.47 (s, 1H), 6.44 (s, 1H), 6.04 (s, 1H), 4.83 (d, J = 1.4 Hz, methylsilyl)phenyl trifluoromethanesulphonate (0.06 mL;
2H), 4.23–4.31 (m, 2H), 3.87 (d, J = 1.4 Hz, 3H), 1.32 (t, J = 7.1 0.25 mmol,
1
equiv.), methyl 2-(bromomethyl)acrylate
Hz, 3H); 13C NMR (126 MHz, CDCl3): δ 188.0, 166.1, 165.2, (0.045 mL; 0.375 mmol, 1.5 equiv.), and CsF (0.152 g; 2 mmol,
162.2, 135.2, 130.8, 126.7, 119.2, 106.4, 99.1, 66.5, 61.1, 55.7, 4 equiv.) in DMF-d7 (0.75 mL), methyl 2-[(2-(formyl-d)phenoxy)
14.2; IR (CHCl3): 2923, 2854, 1681, 1602, 1561, 1261, 1200, methyl]acrylate 3aa(D) was obtained as a light yellow gummy
772, 665 cm−1; HRMS (+ESI) Calcd for C14H17O5 [M + H]+: product (0.040 g, 72% yield) after purification by flash chrom-
265.1076; found: 265.1078.
atography using hexane/EtOAc (9 : 1) as the eluent; 1H NMR
(500 MHz, CDCl3): δ 7.84 (dd, J1 = 1.8 Hz, J2 = 7.7 Hz, 1H),
7.51–7.57 (m, 1H), 7.03–7.08 (m, 1H), 7.01 (d, J = 8.4 Hz, 1H),
6.45 (d, J = 1.0 Hz, 1H), 6.04 (d, J = 0.9 Hz, 1H), 4.86 (t, J =
5-Methoxy-2-[(2-methylallyl)oxy]benzaldehyde (3gc) and
4-methoxy-2-[(2-methylallyl)oxy]benzaldehyde (3g′c)
On applying the general experimental procedure using 1.6 Hz, 2H), 3.81 (s, 3H); 13C NMR (126 MHz, CDCl3): δ 189.0
4-methoxy-2-(trimethylsilyl)phenyl trifluoromethanesulpho- (t, J = 27.4 Hz), 165.6, 160.4, 135.9, 135.0, 128.7, 126.9, 125.0 (t,
nate (0.13 mL; 0.5 mmol, 1 equiv.), 3-bromo-2-methylpropene J = 3.2 Hz), 121.2, 112.8, 66.6, 52.1; IR (CHCl3): 2913, 2839,
(0.075 mL; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4 1644, 1595, 1481, 1446, 1283, 1231, 758, 666 cm−1; HRMS
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(+ESI) Calcd for C12H12DO4 [M + H]+: 222.0877; found: 0.5 mmol, 1 equiv.), (2-bromoallylsulfonyl)benzene (0.195 g;
222.0876.
0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4 equiv.) in
DMF (2 mL), 2-methyl-3-(phenylsulfonyl)-2H-benzo[g]
chromen-2-ol 4cf was obtained as a light yellow solid (0.106 g,
General procedure for the synthesis of 2-methyl-3-
(arylsulfonyl)-2H-chromen-2-ol derivatives (4)
60% yield) after purification by flash chromatography using
An oven-dried round bottom flask (50 mL capacity) equipped hexane/EtOAc (4 : 1) as the eluent; mp: 120–123 °C; 1H NMR
with a magnetic stir bar was evacuated and purged with argon. (500 MHz, CDCl3): δ 7.96–8.00 (m, 2H), 7.94 (s, 1H), 7.83 (s,
o-Silyl aryl triflate (0.5 mmol, 1 equiv.), 2-bromoallyl aryl- 1H), 7.79 (dd, J1 = 0.6 Hz, J2 = 8.2 Hz, 1H), 7.67 (dd, J1 = 0.5 Hz,
sulfones 2f–h (0.75 mmol, 1.5 equiv.), CsF (2 mmol, 4 equiv.) J2 = 8.2 Hz, 1H), 7.61 (m, 1H), 7.51–7.56 (m, 2H), 7.46 (m, 1H),
and DMF (2 mL) were added successively at room temperature. 7.37 (m, 1H), 7.29 (s, 1H), 1.61 (s, 3H); 13C NMR (126 MHz,
The reaction mixture was stirred at room temperature for 3 h. CDCl3): δ 149.3, 140.2, 137.0, 136.0, 135.2, 133.6, 130.3, 129.3,
Water (10 mL) was added to the reaction mixture and the 129.1, 128.6, 128.3, 128.2, 126.9, 124.9, 119.5, 112.6, 97.6, 26.6;
organic layer was extracted with EtOAc (20 × 2 mL). The com- IR (CHCl3): 3435, 3056, 2940, 1688, 1630, 1456, 1300, 1123,
bined organic phases were washed with brine and dried over 867, 750, 683, 640 cm−1; HRMS (+ESI) Calcd for C20H15O3S
sodium sulfate. The solvent was removed and the residue was [M − H2O]+: 335.0742; found: 335.0732.
purified by column chromatography on silica gel using
hexanes/ethyl acetate as the eluent.
5-Methoxy-2-methyl-3-(phenylsulfonyl)-2H-chromen-2-ol (4hf)
On applying the general experimental procedure using
3-methoxy-2-(trimethylsilyl)phenyl trifluoromethanesulphonate
2-Methyl-3-(phenylsulfonyl)-2H-chromen-2-ol (4af)18
On applying the general experimental procedure using 2-(tri- (0.13 mL; 0.5 mmol, 1 equiv.), (2-bromoallylsulfonyl)benzene
methylsilyl)phenyl trifluoromethanesulfonate (0.12 mL; (0.195 g; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4
0.5 mmol, 1 equiv.), (2-bromoallylsulfonyl)benzene (0.195 g; equiv.) in DMF (2 mL), 5-methoxy-2-methyl-3-(phenylsulfonyl)-
0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4 equiv.) in 2H-chromen-2-ol 4hf was obtained as a yellow solid (0.106 g, 64%
DMF (2 mL), 2-methyl-3-(phenylsulfonyl)-2H-chromen-2-ol 4af yield) after purification by flash chromatography using hexane/
1
was obtained as a yellow solid (0.101 g, 67% yield) after purifi- EtOAc (4 : 1) as the eluent; mp: 123–125 °C; H NMR (500 MHz,
cation by flash chromatography using hexane/EtOAc (4 : 1) as the CDCl3): δ 8.18 (s, 1H), 7.94 (d, J = 8.0 Hz, 2H), 7.59 (t, J = 7.8 Hz,
1
eluent; mp: 138–141 °C; H NMR (500 MHz, CDCl3): δ 7.93–7.98 1H), 7.49–7.53 (m, 2H), 7.22–7.30 (m, 1H), 6.55 (d, J = 8.2 Hz,
(m, 2H), 7.81 (s, 1H), 7.62 (m, 1H), 7.54 (t, J = 7.7 Hz, 2H), 1H), 6.50 (d, J = 8.4 Hz, 1H), 3.88 (s, 3H), 1.77 (brs, 1H), 1.54 (s,
7.32–7.38 (m, 2H), 7.04 (m, 1H), 6.96 (d, J = 8.7 Hz, 1H), 3.64 (brs, 3H); 13C NMR (126 MHz, CDCl3): δ 157.4, 153.6, 140.7, 133.7,
1H), 1.61 (s, 3H); 13C NMR (126 MHz, CDCl3): δ 152.7, 140.3, 133.3, 131.6, 130.7, 129.1, 128.1, 109.4, 108.6, 103.6, 97.3, 55.8,
135.2, 133.9, 133.5, 133.2, 129.4, 129.1, 128.1, 122.2, 118.2, 116.9, 26.2; IR (CHCl3): 3422, 3058, 2926, 1718, 1606, 1469, 1305, 1148,
97.4, 26.5; IR (CHCl3): 3440, 3060, 2945, 1690, 1620, 1450, 1300, 1099, 746, 688 cm−1; HRMS (+ESI) Calcd for C17H15O4S [M −
1123, 860, 750, 680, 640 cm−1; HRMS (+ESI) Calcd for C16H13O3S H2O]+: 315.0691; found: 315.0673.
[M − H2O]+: 285.0585; found: 285.0580.
6-Methyl-7-(phenylsulfonyl)-6H-[1,3]dioxolo[4,5g]chromen-6-ol
6,7-Dimethoxy-2-methyl-3-(phenylsulfonyl)-2H-chromen-2-ol (4bf) (4if)
On applying the general experimental procedure using 4,5- On applying the general experimental procedure using 5-(tri-
dimethoxy-2-(trimethylsilyl)
trifluoromethanesulfonate methylsilyl)benzo[d][1,3]-dioxol-6-yltrifluoromethanesulfonate
(0.146 mL; 0.5 mmol, 1 equiv.), (2-bromoallylsulfonyl)benzene (0.10 mL; 0.5 mmol, 1 equiv.), (2-bromoallylsulfonyl)benzene
(0.195 g; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4 (0.195 g; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4
equiv.) in DMF (2 mL), 6,7-dimethoxy-2-methyl-3-(phenylsulfo- equiv.) in DMF (2 mL), 6-methyl-7-(phenylsulfonyl)-6H-[1,3]
nyl)-2H-chromen-2-ol 4bf was obtained as a light brown dioxolo[4,5g]chromen-6-ol 4if was obtained as a yellow solid
gummy product (0.098 g, 54% yield) after purification by flash (0.111 g, 64% yield) after purification by flash chromatography
chromatography using hexane/EtOAc (4 : 1) as the eluent; 1H using hexane/EtOAc (4 : 1) as the eluent; mp: 162–164 °C; 1H
NMR (500 MHz, CDCl3): δ 7.91–7.96 (m, 2H), 7.76 (s, 1H), NMR (500 MHz, CDCl3): δ 7.93 (d, J = 7.2 Hz, 2H), 7.69 (s, 1H),
7.59–7.62 (m, 1H), 7.50–7.55 (m, 2H), 6.79 (s, 1H), 6.52 (s, 1H), 7.55 (dt, J1 = 1.6 Hz, J2 = 2.5 Hz, 1H), 7.52 (t, J = 7.6 Hz, 2H), 6.74
3.87 (s, 3H), 3.86 (s, 3H), 1.58 (s, 3H); 13C NMR (126 MHz, (s, 1H), 6.48 (s, 1H), 5.97 (dd, J1 = 1.2 Hz, J2 = 5.3 Hz, 2H), 3.67 (s,
CDCl3): δ 153.6, 148.4, 144.6, 140.8, 135.4, 133.3, 130.5, 129.1, 1H), 1.57 (s, 3H); 13C NMR (126 MHz, CDCl3): δ 151.8, 149.7,
128.0, 110.6, 109.9, 100.6, 97.6, 56.4, 56.2, 26.2; IR (CHCl3): 143.0, 140.7, 135.4, 133.4, 130.4, 129.1, 128.0, 111.2, 107.1, 101.8,
3445, 3058, 2940, 1691, 1617, 1453, 1297, 1123, 857, 750, 681, 99.0, 97.7, 26.1; IR (CHCl3): 3418, 3060, 2922, 1746, 1619, 1479,
639 cm−1; HRMS (+ESI) Calcd for C18H17O5S [M − H2O]+: 1303, 1219, 1146, 931, 770, 686 cm−1; HRMS (+ESI) Calcd for
345.0797; found: 345.0787.
C17H13O5S [M − H2O]+: 329.0484; found: 329.0490.
2-Methyl-3-tosyl-2H-chromen-2-ol (4ag)18
2-Methyl-3-(phenylsulfonyl)-2H-benzo[g]chromen-2-ol (4cf)
On applying the general experimental procedure using 3-(tri- On applying the general experimental procedure using 2-(tri-
methylsilyl)-2-naphthyl-trifluoromethanesulfonate (0.14 mL; methylsilyl)phenyl trifluoromethanesulfonate (0.12 mL;
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0.5 mmol, 1 equiv.), 1-(2-bromoallylsulfonyl)-4-methylbenzene methylbenzene (0.206 g; 0.75 mmol, 1.5 equiv.), and CsF
(0.206 g; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4 (0.304 g; 2 mmol, 4 equiv.) in DMF (2 mL), 5-methoxy-2-
equiv.) in DMF (2 mL), 2-methyl-3-tosyl-2H-chromen-2-ol 4ag methyl-3-tosyl-2H-chromen-2-ol 4hg was obtained as a yellow
was obtained as a yellow solid (0.104 g, 66% yield) after purifi- solid (0.108 g, 62% yield) after purification by flash chromato-
cation by flash chromatography using hexane/EtOAc (4 : 1) as graphy using hexane/EtOAc (4 : 1) as the eluent; mp:
the eluent; mp: 158–160 °C; 1H NMR (500 MHz, CDCl3): δ 7.82 129–131 °C; 1H NMR (500 MHz, CDCl3): δ 8.15 (s, 1H), 7.82 (d,
(d, J = 8.4 Hz, 2H), 7.78 (s, 1H), 7.28–7.35 (m, 4H), 7.03 (m, J = 8.3 Hz, 2H), 7.31 (d, J = 8.2 Hz, 2H), 7.26 (t, J = 8.3 Hz, 1H),
1H), 6.95 (dd, J1 = 0.8 Hz, J2 = 7.9 Hz, 1H), 3.62 (brs, 1H), 2.43 6.55 (d, J = 8.3 Hz, 1H), 6.49 (d, J = 8.3 Hz, 1H), 3.87 (s, 3H),
(s, 3H), 1.61 (s, 3H); 13C NMR (126 MHz, CDCl3): δ 152.7, 2.41 (s, 3H), 1.76 (brs, 1H), 1.54 (s, 3H); 13C NMR (126 MHz,
144.7, 137.4, 134.7, 134.4, 133.1, 129.8, 129.4, 128.3, 122.3, CDCl3): δ 157.4, 153.6, 144.4, 137.6, 133.6, 131.9, 130.3, 129.7,
118.4, 117.0, 97.5, 26.5, 21.6; IR (CHCl3): 3451, 3055, 2955, 128.2, 109.3, 108.6, 103.5, 97.3, 55.7, 26.1, 21.6; IR (CHCl3):
1694, 1619, 1454, 1296, 1139, 865, 767, 680, 638 cm−1; HRMS 3431, 3055, 2926, 1694, 1606, 1469, 1299, 1144, 1097, 865, 776,
(+ESI) Calcd for C17H15O3S [M − H2O]+: 299.0742; found: 673 cm−1; HRMS (+ESI) Calcd for C18H17O4S [M − H2O]+:
299.0746.
329.0848; found: 329.0844.
6,7-Dimethoxy-2-methyl-3-tosyl-2H-chromen-2-ol (4bg)
6-Methyl-7-tosyl-6H-[1,3]dioxolo[4,5g]chromen-6-ol (4ig)
On applying the general experimental procedure using On applying the general experimental procedure using 5-(tri-
4,5-dimethoxy-2-(trimethylsilyl) trifluoromethanesulfonate methylsilyl)benzo[d][1,3]-dioxol-6-yltrifluoromethanesulfonate
(0.146 mL; 0.5 mmol, 1 equiv.), 1-(2-bromoallylsulfonyl)-4- (0.10 mL; 0.5 mmol, 1 equiv.), 1-(2-bromoallylsulfonyl)-4-
methylbenzene (0.206 g; 0.75 mmol, 1.5 equiv.), and CsF methylbenzene (0.206 g; 0.75 mmol, 1.5 equiv.), and CsF
(0.304 g; 2 mmol, 4 equiv.) in DMF (2 mL), 6,7-dimethoxy-2- (0.304 g; 2 mmol, 4 equiv.) in DMF (2 mL), 6-methyl-7-tosyl-
methyl-3-tosyl-2H-chromen-2-ol 4bg was obtained as a light 6H-[1,3]dioxolo[4,5g]chromen-6-ol 4ig was obtained as a yellow
brown gummy product (0.110 g, 58% yield) after purification solid (0.101 g, 56% yield) after purification by flash chromato-
by flash chromatography using hexane/EtOAc (4 : 1) as the graphy using hexane/EtOAc (4 : 1) as the eluent; mp:
1
1
eluent; H NMR (500 MHz, CDCl3): δ 7.81 (d, J = 8.4 Hz, 2H), 166–168 °C; H NMR (500 MHz, CDCl3): δ 7.80 (d, J = 8.3 Hz,
7.72 (s, 1H), 7.31 (d, J = 7.9 Hz, 2H), 6.78 (s, 1H), 6.52 (s, 1H), 2H), 7.65 (s, 1H), 7.32 (d, J = 7.9 Hz, 2H), 6.73 (s, 1H), 6.48 (s,
3.86 (s, 3H), 3.85 (s, 3H), 2.42 (s, 3H), 1.58 (s, 3H); 13C NMR 1H), 5.97 (dd, J1 = 1.2 Hz, J2 = 5.1 Hz, 2H), 3.65 (s, 1H), 2.42 (s,
(126 MHz, CDCl3): δ 153.5, 148.4, 144.5, 144.4, 137.8, 134.9, 3H), 1.56 (s, 3H); 13C NMR (126 MHz, CDCl3): δ 151.7, 149.6,
130.8, 129.7, 128.1, 110.6, 110.0, 100.6, 97.6, 56.4, 56.1, 26.2, 144.5, 142.9, 137.7, 134.9, 130.8, 129.8, 128.1, 111.2, 107.1,
26.1; IR (CHCl3): 3444, 3057, 2940, 1685, 1610, 1440, 1297, 101.8, 99.0, 97.7, 26.1, 21.6; IR (CHCl3): 3422, 3051, 2922,
1145, 865, 746, 682, 643 cm−1; HRMS (+ESI) Calcd for 1744, 1623, 1479, 1385, 1262, 1144, 815, 772, 680 cm−1; HRMS
C19H19O5S [M − H2O]+: 359.0953; found: 359.0950.
(+ESI) Calcd for C18H15O5S [M − H2O]+: 343.0640; found:
343.0650.
2-Methyl-3-tosyl-2H-benzo[g]chromen-2-ol (4cg)
3-[(4-Chlorophenyl)sulfonyl]-2-methyl-2H-chromen-2-ol (4ah)
On applying the general experimental procedure using 3-(tri-
methylsilyl)-2-naphthyl-trifluoromethanesulfonate (0.14 mL; On applying the general experimental procedure using 2-(tri-
0.5 mmol, 1 equiv.), 1-(2-bromoallylsulfonyl)-4-methylbenzene methylsilyl)phenyl trifluoromethanesulfonate (0.12 mL;
(0.206 g; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4 0.5 mmol, 1 equiv.), 1-(2-bromoallylsulfonyl)-4-chlorobenzene
equiv.) in DMF (2 mL), 2-methyl-3-tosyl-2H-benzo[g]chromen- (0.221 g; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol, 4
2-ol 4cg was obtained as a light yellow solid (0.112 g, 61% equiv.) in DMF (2 mL), 3-[(4-chlorophenyl)sulfonyl]-2-methyl-
yield) after purification by flash chromatography using hexane/ 2H-chromen-2-ol 4ah was obtained as a yellow solid (0.098 g,
EtOAc (4 : 1) as the eluent; mp: 155–157 °C; 1H NMR 58% yield) after purification by flash chromatography using
(500 MHz, CDCl3): δ 7.92 (s, 1H), 7.87 (s, 1H), 7.85 (d, J = 6.0 hexane/EtOAc (4 : 1) as the eluent; mp: 135–137 °C; 1H NMR
Hz, 2H), 7.81 (d, J = 8.2 Hz, 1H), 7.69 (d, J = 8.2 Hz, 1H), 7.48 (500 MHz, CDCl3): δ 7.88 (d, J = 8.7 Hz, 2H), 7.81 (s, 1H), 7.50
(m, 1H), 7.38 (m, 1H), 7.35 (d, J = 8.1 Hz, 2H), 7.31 (s, 1H), 3.74 (d, J = 8.7 Hz, 2H), 7.32–7.39 (m, 2H), 7.05 (dt, J1 = 1.0 Hz, J2 =
(brs, 1H), 2.44 (s, 3H), 1.59 (s, 3H); 13C NMR (126 MHz, 7.5 Hz, 1H), 6.95 (d, J = 8.2 Hz, 1H), 3.57 (s, 1H), 1.65 (s, 3H);
CDCl3): δ 149.3, 144.8, 137.4, 137.1, 136.1, 134.7, 130.2, 129.8, 13C NMR (126 MHz, CDCl3): δ 152.8, 140.2, 139.1, 135.7, 133.6,
129.4, 128.5, 128.4, 128.3, 126.9, 124.9, 119.6, 112.6, 97.7, 26.6, 133.4, 129.7, 129.6, 129.5, 122.4, 118.2, 117.1, 97.5, 26.8; IR
21.7; IR (CHCl3): 3440, 3064, 2951, 1690, 1630, 1450, 1299, (CHCl3): 3431, 3055, 2918, 1694, 1619, 1453, 1312, 1150, 942,
1211, 860, 770, 682, 640 cm−1; HRMS (+ESI) Calcd for 770, 755, 707 cm−1; HRMS (+ESI) Calcd for C16H12ClO3S
C21H17O3S [M − H2O]+: 349.0898; found: 349.0890.
[M − H2O]+: 319.0196; found: 319.0201.
5-Methoxy-2-methyl-3-tosyl-2H-chromen-2-ol (4hg)
3-[(4-Chlorophenyl)sulfonyl]-2-methyl-2H-benzo[g]chromen-2-
ol (4ch)
On applying the general experimental procedure using
3-methoxy-2-(trimethylsilyl)phenyl
trifluoromethanesulpho- On applying the general experimental procedure using 3-(tri-
nate (0.13 mL; 0.5 mmol, 1 equiv.), 1-(2-bromoallylsulfonyl)-4- methylsilyl)-2-naphthyl-trifluoromethanesulfonate (0.14 mL;
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0.5 mmol, 1 equiv.), 1-(2-bromoallylsulfonyl)-4-chlorobenzene
(0.221 g; 0.75 mmol, 1.5 equiv.), and CsF (0.304 g; 2 mmol,
4 equiv.) in DMF (2 mL), 3-[(4-chlorophenyl)sulfonyl]-2-methyl-
2H-benzo[g]chromen-2-ol 4ch was obtained as a light yellow
solid (0.114 g, 59% yield) after purification by flash chromato-
graphy using hexane/EtOAc (4 : 1) as the eluent; mp:
157–159 °C; 1H NMR (500 MHz, CDCl3): δ 7.94 (s, 1H), 7.91 (d,
J = 8.7 Hz, 2H), 7.84 (s, 1H), 7.80 (d, J = 8.1 Hz, 1H), 7.68 (d, J =
8.2 Hz, 1H), 7.45–7.52 (m, 3H), 7.36–7.41 (m, 1H), 7.30 (s, 1H),
1.67 (brs, 1H), 1.65 (s, 3H); 13C NMR (126 MHz, CDCl3):
δ 149.2, 140.3, 138.8, 136.6, 136.1, 135.7, 130.5, 129.8, 129.5,
129.4, 128.6, 128.4, 126.9, 125.0, 119.4, 112.7, 97.7, 26.9; IR
(CHCl3): 3422, 3056, 2922, 1742, 1632, 1475, 1316, 1211, 929,
763, 705, 680 cm−1; HRMS (+ESI) Calcd for C20H14ClO3S
[M − H2O]+: 369.0352; found: 369.0360.
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2-(But-2-en-1-yloxy)benzaldehyde (3ai)23
On applying the general experimental procedure using 2-(tri-
methylsilyl)phenyl trifluoromethanesulfonate (0.12 mL;
0.5 mmol, 1 equiv.), crotyl bromide (0.077 mL; 0.75 mmol, 1.5
equiv.), and CsF (0.304 g; 2 mmol, 4 equiv.) in DMF (2 mL), 2-
(but-2-en-1-yloxy)benzaldehyde 3ai was obtained as a colour-
less oil (0.058 g, 66% yield) after purification by flash chrom-
atography using hexane/EtOAc (9 : 1) as the eluent; 1H NMR
(500 MHz, CDCl3): δ 10.50 (s, 1H), 7.83 (dd, J1 = 1.8 Hz, J2 = 7.7
Hz, 1H), 7.52 (m, 1H), 6.93–7.02 (m, 2H), 5.70–5.92 (m, 2H),
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δ 189.9, 161.1, 135.8, 130.9, 128.3, 125.2, 124.9, 120.6, 112.8,
69.1, 17.8; IR (CHCl3): 2920, 2850, 1688, 1483, 1456,
1285, 1218, 756, 645 cm−1; HRMS (+ESI) Calcd for C11H13O2
[M + H]+: 177.0916; found: 177.0923.
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There are no conflicts to declare.
Acknowledgements
We are grateful to the director of the CSIR-NEIST, Jorhat, India
for showing interest in this work and providing us with facili-
ties. AS acknowledges the DST, New Delhi, India for the
DST-Inspire fellowship grants.
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