Gold-catalyzed cyclization of enediynes and arenediynes to 6H-benzo[c]chromen-6-one and dibenzo[c,h]chromen-6-one derivatives

Article abstract of DOI:10.1016/j.tet.2019.01.021

The efficient synthesis of 6H-benzo[c]chromen-6-one and dibenzo[c,h]chromen-6-one derivatives is described. Thus, treatment of arenediynes 1 and enediynes 5 with 5 mol % Ph₃PAuCl and 10 mol % of AgSbF₆ in refluxing toluene gave dibenzo[c,h]chromen-6-ones 4 and 6H-benzo[c]chromen-6-ones 6, in good yields, respectively.

Full text of DOI:10.1016/j.tet.2019.01.021

Accepted Manuscript
Gold-Catalyzed Cyclization of Enediynes and Arenediynes to 6H-Benzo[c]chromen-6-
one and Dibenzo[c,h]chromen-6-one Derivatives
Chin-Chau Chen, Chia-Ling Hsu, Ming-Jung Wu
PII:
S0040-4020(19)30049-3
https://doi.org/10.1016/j.tet.2019.01.021
TET 30073
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 1 November 2018
Revised Date: 4 January 2019
Accepted Date: 4 January 2019
Please cite this article as: Chen C-C, Hsu C-L, Wu M-J, Gold-Catalyzed Cyclization of Enediynes and
Arenediynes to 6H-Benzo[c]chromen-6-one and Dibenzo[c,h]chromen-6-one Derivatives, Tetrahedron,
https://doi.org/10.1016/j.tet.2019.01.021.
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ACCEPTED MANUSCRIPT
Gold-Catalyzed Cyclization of Enediynes and
Arenediynes to 6H-Benzo[c]chromen-6-one and
Dibenzo[c,h]chromen-6-one Derivatives
Chin-Chau Chen,a Chia-Ling Hsua and Ming-Jung Wua,b,*
aDepartment of Chemistry, National Sun Yat-sen University, Kaohsiung, Taiwan
bDepartment of Medicinal and Applied Chemistry, Kaohsiung Medical University,
Kaohsiung, Taiwan
ABSTRACT
The
efficient
synthesis
of
6H-benzo[c]chromen-6-one
and
dibenzo[c,h]chromen-6-one derivatives is described. Thus, treatment of arenediynes 1
and enediynes 5 with 5 mol % Ph3PAuCl and 10 mol % of AgSbF6 in refluxing
toluene gave dibenzo[c,h]chromen-6-ones 4 and 6H-benzo[c]chromen-6-ones 6, in
good yields, respectively.
Molecules containing 6H-benzo[c]chromen-6-one1 and dibenzo[c,h]chromen-6-one2
substructures are often found in biological active natural products and compounds of
pharmaceutical interest; therefore the development of efficient synthetic methods to
construct these ring systems and the biological active compounds themselves have
both attracted much attention from organic chemists.3 Recently transition
metal-catalyzed cyclization reaction of enediyne derivatives to polyaromatic
compounds has been widely studied.4 However none of them has been applied to the
synthesis of 6H-benzo[c]chromen-6-one and dibenzo[c,h]chromen-6-one derivatives.
One of the related approaches was reported by Yao5 to give
indeno[1,2-c]isochromen-5(11H)-ones and indeno[1,2-b]pyran-2(5H)-ones. In this
case, they introduced the terminal alkyne and carboxylic acid functionality to proceed
with the C1-C5 cyclization of enediynes. Asao reported the gold-catalyzed cyclization

ACCEPTED MANUSCRIPT
reaction of 2-akynyl benzoates to give isocumarines.6 Herein, we wish to introduce
internal alkyne as well as terminal alkyne and methyl carboxylate into the enediyne
system. According to Asao’s and our previous studies,7 we anticipate that these
enediynes
would
undergo
the
C1-C6
cyclization
to
produce
6H-benzo[c]chromen-6-one and dibenzo[c,h]chromen-6-one derivatives.
The starting enediynes were prepared from methyl 2-ethynylbenzoate (2) according to
the procedures described in our previous report.6a (scheme 1) Palladium-catalyzed
Sonogashira coupling reaction of 2 with 1,2-diiodobenzene gave 3 in 82% yield.
Compound 3 was then coupled with various terminal alkynes under similar reaction
conditions to give 1a-l in 80-98% yields. Compound 1l was desilylated using TBAF
and gave 1m in 98% yield.
Scheme 1. The preparation of compound 1

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Our initial attempt for the cyclization reaction was carried out by the treatment of 1a
with 5 mol % Ph3PAuCl and 10 mol % of AgSbF6 in MeOH under refluxing
temperature for 2 h. Compound 4a was obtained in 75% yield. (Table 1, entry 1) We
then screened other solvents, such as DCM, THF and toluene, and found under
refluxing toluene the reaction went to completion within 10 minutes to give
compound 2a in 98% yield. (Table 1, entry 4) Other gold catalysts, such as
(furyl)3PAuCl, (C6F5)3PAuCl and cat-I, were also employed in this study. It was
found that these catalysts were not as good as Ph3PAuCl. (Table 1, entries 5-7). We
also examined silver trilate (AgOTf) as the co-catalyst and found it was inferior to
AgSbF6. (Table 1, entry 8) As the combination of 5 mol % Ph3PAuCl and 10 mol %
of AgSbF6 in refluxing toluene showed the best condition for the cyclization of 1a to
4a, this reaction condition was chosen for further study.
Table 1. Optimization of reaction conditions
catalyst
temp
(oC)
time
(h)
yield
(%)
entry
1
solvent
MeOH
(equiv)
Ph3PAuCl (0.05)/
AgSbF6 (0.1)
Ph3PAuCl (0.05)/
AgSbF6 (0.1)
Ph3PAuCl (0.05)/
reflux
2
75
2
3
DCM
THF
reflux
reflux
2
85
80
24

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AgSbF6 (0.1)
Ph3PAuCl (0.05)/
AgSbF6 (0.1)
4
5
6
7
8
toluene
toluene
toluene
toluene
toluene
reflux
reflux
reflux
reflux
reflux
10 (min)
98
(furyl)3PAuCl (0.05)/
AgSbF6 (0.1)
24
24
1
65
(C6F5)3PAuCl (0.05)/
AgSbF6 (0.1)
26a
78
Cat-I (0.05)b/
AgSbF6 (0.1)
Ph3PAuCl (0.05)/
AgOTf (0.1)
24
15a
a recovered most of the starting material . b Cat-I:
1a
Table 2. Scope of dibenzo[c,h]chromen-6-onesa

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a
Reaction conditions: (0.3 mmol), Ph PAuCl (0.01 mmol), AgSbF (0.02 mmol),
1
3
6
toluene (4 mL), 10 min, isolated yield. b Reaction time is 30 min.
To explore the scope of the gold-catalyzed cyclization reaction for the synthesis of
dibenzo[c,h]chromen-6-ones, compounds 1b-k and 1m were subjected to the
optimized reaction conditions and the results are summarized in Table 2. The results
indicated all the substrates 1b-k underwent cyclization very smoothly to give the
corresponding dibenzo[c,h]chromen-6-one derivatives 4b-k in 60-92% yields.
Compound 1m bearing terminal alkyne was structurally similar to Yao’s system and
was subjected to the cyclization reaction conditions. The only product we isolated was
compound 4m, the structure of which was unambiguously determined by Single
X-ray crystallography. (Figure 1) This result indicated that this reaction proceeded
C1-C6 instead of C1-C5 cyclization of the arenediyne under the described reaction
conditions.

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Figure 1. ORTEP drawing of 4m showing thermal ellipsoids at the 30% probability
level.
The enediyne derivatives 5a-h were prepared according to our reported procedures7a
then subjected to the gold-catalyzed cyclization reactions. Again, all the reactions
proceeded very smoothly to give 6H-benzo[c]chromen-6-one derivatives 6a-b and
6d-h in good yields except for compound 6c albeit in lower yield.
Table 3. Scope of 6H-benzo[c]chromen-6-ones
R
R
Ph3PAuCl (0.05 equiv)
AgSbF6 (0.1 equiv)
O
toluene, reflux, 45 min
CO2Me
MeO
O
5
6
Me
n-Pr
O
O
O
O
O
O
O
O
6b
6c
; 72%
; 42%
6a
; 73%
6d; 80%
CF3
Cl
Br
OHC
O
O
O
O
O
O
O
O
6h; 76%
6e
; 80%
6g
; 57%
6f
; 98%
In order to understand the reaction mechanism and role of toluene in depth, compound
1n was prepared followed by the procedure as for scheme 1 starting from benzyl
2-iodobenzoate. Treatment of compound 1n with 5 mol % Ph3PAuCl and 10 mol % of

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AgSbF6 in refluxing toluene for 1 h gave compound 4a in 56% yield along with a
mixture of 2-benzyltoluene and 4-benzyltoluene. (Scheme 2)
Scheme 2. Reaction of benzyl benzoate derivative
nPr
nPr
Me
Ph3PAuCl
AgSbF6
Me
+
+
Ph
toluene, reflux, 1 h
O
O
Ph
O
Ph
O
4a
1n
(56%)
41%
Based upon these results, we proposed the reaction mechanism of this gold-catalyzed
cyclization reaction as shown in Scheme 3. First of all, the gold zed catalyst would
coordinate to one of the triple bond in compound 1 followed by cyclization to give
intermediate 7. The solvent, toluene, would attack the R’ group, either methyl or
benzyl, via Frieldel-Crafts alkylation reaction 6b to give 8. The isolation of ortho- and
para-benzyltoluenes in Scheme 2 is the evidence. Proton-gold exchange reaction
would convert 8 to 9. The gold catalyst would then coordinate with the other triple
bond again to promote another cyclization reaction and give 10. Rearomatization by
removing the proton of 10 would provide 11. Finally, compound 11 could be
converted to the final product 4 by proton-gold exchange reaction.
Scheme 3. Proposed reaction mechanism

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Another possible pathway is summarized in Scheme 4. The first step could involve a
Au-cataylzed Bergman cyclization to form an ionoic counterpart of the p-benzyne
product 128 followed by trapping of the carbocation by the oxygen of the ester group,
subsequently undergoing demethylation and protonation to give the final product 4. If
this is the case, when the same catalyst as in Yao’s study was employed in the
cyclization of compound 1m, the C1-C5 cyclization product should be obtained
instead of the C1-C6 product. Therefore, compound 1mwas treated with 5 mol % of
Ph3PAuNTf2 in toluene and the solution was stirred for 18 hours at room temperature.
The only product obtained was compound 4m and the yield was 71%. (Scheme 5)
With this result, we can conclude that the mechanism proposed in Scheme 3 is more
reasonable. The reason to cause the different outcome between ours and Yao’s results
could be the functionality between ester and carboxylic acid although it is not clear
why at this stage.
Scheme 4. Proposed alternate pathway of the cascade cyclization reaction.

ACCEPTED MANUSCRIPT
Scheme 5. Cyclization reaction of 1m using Ph3PAuNTf2.
Conclusion
In
conclusion,
we
have
developed
an
efficient
synthesis
of
6H-benzo[c]chromen-6-one and dibenzo[c,h]chromen-6-one derivatives by
gold-catalyzed cyclization reaction of benzoate-containing enediyne and arenediyne
derivatives. This reaction proceeded C1-C6 cyclization that is different with the
C1-C5 cyclization of enediynes bearing benzoic acid functionality reported by Yao.
We believe this finding would not only have a strong impact on synthetic organic
chemistry but also provide more information for gold-catalyzed cyclization reactions.
Experimental Section
Procedure for Sonogashira Coupling Reactions of Aryl Iodides Compound 3,
1,2-Diiodobenezene and cis-1,2-Dichloroethylene to Compounds 1a−l, 3, and 5a−h.
Represented
Reaction
Conditions
for
Preparation
of
Methyl
2-((2-iodophenyl)ethynyl)benzoate (3). To a stirred solution of 1,2-diiodobenzene
(4.95 g, 15 mmol) in Et2O (100 mL) containing Pd(PPh3)4 (0.75 g, 0.625 mmol) was
added methyl 2-ethynylbenzoate (2) (2.0 g, 12.5 mmol) , CuI (0.24 g, 1.0 mmol) and
n-BuNH2 (1.83 g, 12.3 mmol). The resulting solution was stirred at room temperature
for 6 h, quenched by saturated aqueous NH4Cl (100 mL), and extracted by EtOAc
(100 mL × 2). The combined organic layers were dried over MgSO4. After filtration
and removal of EtOAc, the residue was purified by column chromatography on silica
gel to give methyl 2-((2-iodophenyl)ethynyl)benzoate (3) (3.7 g. 82%).
General
Procedure
for
the
Desilylation
of
methyl

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2-((2-((trimethylsilyl)ethynyl)phenyl)ethynyl)benzoate
(1l)
To
Give
2-((2-Ethynylphenyl)ethynyl)benzoate (1m). To a solution of 1l (1.0 g, 3.0 mmol) in
THF (30 mL) was added tetra-n-butylammonium fluoride (1.2 g, 7.35 mmol). The
resulting solution was stirred at room temperature for 0.5 h, quenched by brine (50
mL), and extracted with EtOAc (two 50 mL portions). The combined organic layers
were dried over MgSO4. After filtration and removal of solvent, the residue was
further purified by column chromatography on silica gel to give methyl
2-((2-ethynylphenyl)ethynyl)benzoate (1m) (0.77 g, 98%)
General Procedure for the Gold-Catalyzed Cyclization of Methyl
2-((2-(pent-1-yn-1-yl)phenyl)ethynyl)benzoate
(1a)
to
11-Propyl-6H-dibenzo[c,h]chromen-6-one (4a). To a solution of 1a (100 mg, 0.3
mmol) in toluene (5 mL) was added Ph3PAuCl (8.2 mg, 5 mol %) and AgSbF6 (11.4
mg, 10 mol%). The resulting solution was stirred in refluxing for 10 min, quenched
by brine (20 mL), and extracted with EtOAc (two 20 mL portions). The combined
organic layers were dried over MgSO4. After filtration and removal of solvent, the
residue was further purified by column chromatography on silica gel to give
11-Propyl-6H-dibenzo[c,h]chromen-6-one (4a) (84.7 mg, 98%)

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Methyl 2-((2-(pent-1-yn-1-yl)phenyl)ethynyl)benzoate (1a)
Yielded 158 mg, 95%; A yellow oil; Rf = 0.4 (10:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 1.04 (t, J = 7.6 Hz, 3H), 1.65 (sext, J = 7.2 Hz, 2H), 2.48 (t, J = 7.2 Hz, 2H),
3.96 (s, 3H), 7.24-7.28 (m, 2H), 7.39 (td, J = 7.6, 1.2 Hz, 1H), 7.43-7.45 (m, 1H),
7.50 (td, J = 7.2, 1.2 Hz, 1H), 7.55-7.57 (m, 1H), 7.67 (dd, J = 8.0, 1.6 Hz, 1H), 7.98
(dd, J = 7.6, 1.2 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 13.6, 21.7, 22.2, 52.1, 79.5,
91.5, 93.5, 94.7, 123.9, 125.6, 126.6, 127.2, 127.9, 128.1, 130.4, 131.5, 131.9, 132.0,
132.1, 134.2, 166.8; MS (70 eV) m/z (%): 302.0 (34) [M+], 258.0 (49), 273.0 (81),
61.0 (100); HRMS (EI-magnetic sector) m/z: [M]+ Calcd for C21H18O2, 302.1307;
Found, 302.1308.
Methyl 2-((2-(hept-1-yn-1-yl)phenyl)ethynyl)benzoate (1b)
Yielded 163 mg, 90%; A yellow oil; Rf = 0.4 (10:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 0.84 (t, J = 7.2 Hz, 3H), 1.29 (x, J = 7.2 Hz, 2H), 1.39-1.47 (m, 2H), 1.63
(quin, J = 7.2 Hz, 2H), 2.49 (t, J = 7.2 Hz, 2H), 3.96 (s, 3H), 7.23-7.28 (m, 2H), 7.39
(td, J = 7.6, 1.2 Hz, 1H), 7.41-7.46 (m, 1H), 7.49 (td, J = 7.6, 1.2 Hz, 1H), 7.54-7.58
(m, 1H), 7.67 (dd, J = 7.6, 1.2 Hz, 1H), 7.98 (dd, J = 8.0, 1.6 Hz, 1H); 13C NMR (100
MHz, CDCl3) δ 13.9, 19.7, 22.2, 28.5, 31.1, 52.1, 79.3, 91.5, 93.5, 95.0, 123.9, 125.6,
126.6, 127.2, 127.9, 128.1, 130.4, 131.5, 131.9, 132.0, 132.1, 134.2, 166.7; MS (70
eV) m/z (%): 330.0 (11) [M+], 287.0 (19), 295.0 (6), 272.0 (100); HRMS
(EI-magnetic sector) m/z: [M]+ Calcd for C23H22O2, 330.1620; Found, 330.1621.
Methyl 2-((2-((4-methoxyphenyl)ethynyl)phenyl)ethynyl)benzoate (1c)
Yielded 191 mg, 95%; A yellow oil; Rf = 0.2 (10:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 3.83 (s, 3H), 3.90 (s, 3H), 6.84-6.88 (m, 2H), 7.27-7.34 (m, 2H), 7.40 (td, J
= 8.0, 1.6 Hz, 1H), 7.46-7.52 (m, 3H), 7.53-7.57 (m, 1H), 7.58-7.64 (m, 1H), 7.70 (dd,
13
J = 7.6, 1.2 Hz, 1H), 7.99 (dd, J = 7.6, 1.2 Hz, 1H); C NMR (100 MHz, CDCl3)
δ 52.1, 55.3, 87.1, 92.1, 93.4, 93.6, 114.0, 115.4, 123.8, 125.5, 126.2, 127.6, 128.0,
128.2, 130.5, 131.7, 131.7, 132.2, 133.2, 134.3, 159.8, 166.7; MS (70 eV) m/z (%):
366.0 (100) [M+], 263.0 (31), 351.0 (60); HRMS (EI-magnetic sector) m/z: [M]+
Calcd for C25H18O3, 366.1256; Found, 366.1259.
Methyl 2-((2-(p-tolylethynyl)phenyl)ethynyl)benzoate (1d)
1
Yielded 164 mg, 85%; A yellow solid; Rf = 0.3 (10:1 Hex/EtOAc); H NMR (400
MHz, CDCl3) δ 2.37 (s, 3H), 3.90 (s, 3H), 7.14 (d, J = 7.8 Hz, 2H), 7.30-7.34 (m, 2H),
7.40 (td, J = 7.8, 1.2 Hz, 1H), 7.44-7.46 (m, 2H), 7.47 (td, J = 7.2, 1.2 Hz, 1H),
7.55-7.57 (m, 1H), 7.60-7.62 (m, 1H), 7.71 (dq, J = 7.8, 1.2 Hz, 1H), 7.99 (dq, J = 7.8,
0.6 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 21.5, 52.1, 87.7, 92.2, 93.3, 93.8, 120.2,

ACCEPTED MANUSCRIPT
123.8, 125.7, 126.0, 127.8, 128.0, 128.2, 129.1, 130.5, 131.6, 131.7, 131.7, 131.8,
132.2, 134.3, 138.6, 166.7; mp 65-66 oC; MS (70 eV) m/z (%): 350.0 (34) [M+], 334.0
(13), 335.0 (22), 57.0 (100); HRMS (EI-magnetic sector) m/z: [M]+ Calcd for
C25H18O2, 350.1307; Found, 350.1304.
Methyl 2-((2-(m-tolylethynyl)phenyl)ethynyl)benzoate (1e)
Yielded 164 mg, 85%; A yellow oil; Rf = 0.3 (10:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 2.31 (s, 3H), 3.90 (s, 3H), 7.15 (d, J = 7.2 Hz, 1H), 7.22 (t, J = 7.8 Hz, 1H),
7.32-7.34 (m, 2H), 7.36 (d, J = 7.8 Hz, 1H), 7.38-7.38 (m, 1H), 7.40 (td, J = 7.8, 1.2
Hz, 1H), 7.47 (td, J = 7.2, 1.2 Hz, 1H), 7.55-7.57 (m, 1H), 7.61-7.62 (m, 1H), 7.73
(dq, J = 7.8, 0.6 Hz, 1H), 8.00 (dq, J = 7.8, 0.6 Hz, 1H); 13C NMR (100 MHz, CDCl3)
δ 21.2, 52.1, 88.0, 92.2, 93.3, 93.8, 123.1, 123.8, 125.8, 126.0, 127.9, 128.0, 128.2,
128.2, 128.7, 129.3, 130.5, 131.7, 131.7, 131.8, 132.1, 132.3, 134.4, 138.0, 166.6; MS
(70 eV) m/z (%): 350.0 (82) [M+], 334.0 (32), 335.0 (60), 57.0 (100); HRMS
(EI-magnetic sector) m/z: [M]+ Calcd for C25H18O2, 350.1307; Found, 350.1304.
Methyl 2-((2-(o-tolylethynyl)phenyl)ethynyl)benzoate (1f)
Yielded 171 mg, 89%; A yellow oil; Rf = 0.4 (10:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 2.48 (s, 3H), 3.88 (s, 3H), 7.15 (td, J = 7.6, 2.0 Hz, 1H), 7.19-7.26 (m, 2H),
7.30-7.35 (m, 2H), 7.39 (td, J = 7.6, 1.2 Hz, 1H), 7.46 (td, J = 7.6, 1.6 Hz, 1H), 7.53
(d, J = 6.8 Hz, 1H), 7.57-7.60 (m, 1H), 7.61-7.67 (m, 2H), 7.99 (dd, J = 7.6, 1.6 Hz,
13
1H); C NMR (100 MHz, CDCl3) δ 20.7, 52.1, 92.0, 92.1, 92.4, 93.3, 123.0, 123.7,
125.5, 125.6, 126.0, 127.9, 128.0, 128.2, 128.4, 129.4, 130.5, 131.6, 131.9, 132.0,
132.0, 132.3, 134.2, 140.4, 166.6; MS (70 eV) m/z (%): 350.0 (89) [M+], 235.0 (60),
276.0 (67), 57.0 (100); HRMS (EI-magnetic sector) m/z: [M]+ Calcd for C25H18O2,
350.1307; Found, 350.1304.
Methyl 2-((2-(phenylethynyl)phenyl)ethynyl)benzoate (1g)
Yielded 181 mg, 98%; A yellow oil; Rf = 0.3 (10:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 3.89 (s, 3H), 7.29-7.35 (m, 5H), 7.39 (td, J = 7.6, 1.2 Hz, 1H), 7.47 (td, J =
7.6, 1.6 Hz, 1H), 7.54-7.59 (m, 3H), 7.60-7.63 (m, 1H), 7.70 (dd, J = 7.6, 1.2 Hz, 1H),
13
7.99 (dd, J = 8.0, 1.6 Hz, 1H); C NMR (100 MHz, CDCl3) δ 52.1, 88.3, 92.3, 93.2,
93.5, 94.4, 123.3, 123.8, 125.8, 128.0, 128.1, 128.3, 128.3, 128.4, 130.5, 131.7, 131.7,
131.8, 131.9, 132.2, 134.3; MS (70 eV) m/z (%): 336.0 (100) [M+], 276.0 (60), 321.0
(88); HRMS (EI-magnetic sector) m/z: [M]+ Calcd for C24H16O2, 336.1150; Found,
336.1153.
Methyl 2-((2-((4-chlorophenyl)ethynyl)phenyl)ethynyl)benzoate (1h)

ACCEPTED MANUSCRIPT
1
Yielded 199 mg, 98%; A yellow solid; Rf = 0.5 (10:1 Hex/EtOAc); H NMR (400
MHz, CDCl3) δ 3.89 (s, 3H), 7.29-7.36 (m, 4H), 7.40 (td, J = 7.6, 1.2 Hz, 1H),
7.46-7.50 (m, 3H), 7.55-7.57 (m, 1H), 7.61-7.63 (m, 1H), 7.68 (dd, J = 7.6, 1.2 Hz,
13
1H), 8.00 (dd, J = 8.0, 1.6 Hz, 1H); C NMR (100 MHz, CDCl3) δ 52.1, 89.3, 92.3,
93.1, 121.8, 123.7, 125.5, 125.9, 128.1, 128.2, 128.3, 128.7, 128.9, 130.5, 131.7,
o
131.8, 131.9, 132.3, 132.9, 134.2, 134.4, 166.6; mp 61-63 C; MS (70 eV) m/z (%):
372.0 (36) [M+2], 370.0 (100) [M+], 272.0 (36), 274.0 (51), 355.0 (53); HRMS
(EI-magnetic sector) m/z: [M]+ Calcd for C24H15O2Cl, 370.0761; Found, 370.0760.
Methyl 2-((2-((4-bromophenyl)ethynyl)phenyl)ethynyl)benzoate (1i)
1
Yielded 223 mg, 98%; A yellow solid; Rf = 0.3 (10:1 Hex/EtOAc); H NMR (400
MHz, CDCl3) δ 3.89 (s, 3H), 7.30-7.51 (m, 8H), 7.53-7.58 (m, 1H), 7.60-7.64 (m, 1H),
13
7.68 (dd, J = 7.6, 1.2 Hz, 1H), 8.00 (dd, J = 8.0, 1.6 Hz, 1H); C NMR (100 MHz,
CDCl3) δ 52.1, 89.4, 92.3, 92.4, 93.1, 122.3, 122.7, 123.7, 125.4, 125.9, 128.2, 128.3,
o
128.3, 130.5, 131.6, 131.7, 131.8, 131.9, 132.3, 133.1, 134.2, 166.6; mp 61-63 C;
MS (70 eV) m/z (%): 416.0 (42) [M+2], 414.0 (42) [M+], 320.0 (44), 57.0 (100);
HRMS (EI-magnetic sector) m/z: [M]+ Calcd for C24H15O2Br, 414.0255; Found,
414.0256.
Methyl 2-((2-((4-(trifluoromethyl)phenyl)ethynyl)phenyl)ethynyl)benzoate (1j)
Yielded 218 mg, 98%; A white solid; Rf = 0.4 (10:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 3.88 (s, 3H), 7.31-7.38 (m, 2H), 7.41 (td, J = 7.8, 1.2 Hz, 1H), 7.49 (td, J =
7.2, 1.2 Hz, 1H), 7.58-7.59 (m, 3H), 7.63-7.69 (m, 4H), 7.99-8.01 (m, 1H); 13C NMR
(100 MHz, CDCl3) δ 52.1, 90.6, 91.9, 92.5, 92.9, 123.6, 125.0, 125.2, 125.2, 125.3,
125.3, 126.1, 128.2, 128.3, 128.6, 130.6, 131.7, 131.8, 131.9, 132.1, 132.3, 134.2,
o
166.5; mp 97-98 C; MS (70 eV) m/z (%): 404.0 (45) [M+], 388.0 (21), 389.0 (29),
61.0 (100); HRMS (EI-magnetic sector) m/z: [M]+ Calcd for C25H15O2F3, 404.1024;
Found, 404.1026.
Methyl 2-((2-((4-formylphenyl)ethynyl)phenyl)ethynyl)benzoate (1k)
1
Yielded 196 mg, 98%; A yellow oil; Rf = 0.4 (5:1 Hex/EtOAc); H NMR (400 MHz,
CDCl3) δ 3.89 (s, 3H), 7.33-7.38 (m, 2H), 7.41 (td, J = 7.6, 1.2 Hz, 1H), 7.49 (td, J =
7.6, 1.2 Hz, 1H), 7.58-7.60 (m, 1H), 7.63-7.66 (m, 1H), 7.68-7.71 (m, 3H), 7.83-7.85
13
(m, 2H), 8.01 (dd, J = 7.6, 1.6 Hz, 1H), 10.01 (s, 1H); C NMR (100 MHz, CDCl3)
δ 52.1, 92.3, 92.4, 92.6, 92.9, 123.6, 124.9, 126.2, 128.2, 128.3, 128.7, 129.5, 129.6,
130.6, 131.7, 132.1, 132.2, 132.3, 134.2, 135.5, 166.5, 191.4; MS (70 eV) m/z (%):
364.0 (100) [M+], 276.0 (43), 321.0 (24), 349.0 (62); HRMS (EI-magnetic sector) m/z:
[M]+ Calcd for C25H16O3, 364.1099; Found, 364.1101.

ACCEPTED MANUSCRIPT
Methyl 2-((2-((trimethylsilyl)ethynyl)phenyl)ethynyl)benzoate (1l)
Yielded 146 mg, 80%; A yellow oil; Rf = 0.7 (10:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 0.25 (s, 9H), 3.96 (s, 3H), 7.26-7.31 (m, 2H), 7.37-7.42 (m, 1H), 7.47-7.52
13
(m, 2H), 7.56-7.59 (m, 1H), 7.69-7.72 (m, 1H), 7.99 (dd, J = 7.8, 0.9 Hz, 1H); C
NMR (100 MHz, CDCl3) δ 52.2, 92.1, 93.1, 98.5, 103.5, 123.8, 125.7, 126.1, 127.8,
128.0, 128.1, 128.2, 129.6, 130.5, 131.6, 131.7, 132.0, 132.4, 132.9, 134.3, 134.4,
138.7, 166.6; MS (70 eV) m/z (%): 332.0 (100) [M+], 61.0 (98), 317.0 (35), 331.0
(58); HRMS (EI-magnetic sector) m/z: [M]+ Calcd for C21H20O2Si, 332.1232; Found,
332.1233.
Methyl 2-((2-ethynylphenyl)ethynyl)benzoate (1m)
1
Yielded 0.77 g, 98%; A yellow oil; Rf = 0.4 (10:1 Hex/EtOAc); H NMR (400 MHz,
CDCl3) δ 3.36 (s, 1H), 3.96 (s, 3H), 7.30 (td, J = 7.6, 1.6 Hz, 1H), 7.35 (td, J = 7.6,
1.6 Hz, 1H), 7.40 (td, J = 7.6, 1.6 Hz, 1H), 7.50 (td, J = 7.6, 1.6 Hz, 1H), 7.54 (dd, J =
7.6, 1.6 Hz, 1H), 7.60 (dd, J = 7.2, 1.2 Hz, 1H), 7.71 (dd, J = 7.6, 1.2 Hz, 1H), 7.98
(dd, J = 8.0, 1.6 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 52.2, 81.1, 82.2, 92.2, 92.6,
123.5, 124.6, 126.3, 128.1, 128.2, 128.5, 130.4, 131.6, 131.9, 132.2, 132.6, 134.4,
166.8; MS (70 eV) m/z (%): 260.0 (49) [M+], 200.0 (62), 217.0 (78), 245.0 (100);
HRMS (EI-magnetic sector) m/z: [M]+ Calcd for C18H12O2, 260.0837; Found,
260.0837.
Benzyl 2-((2-(pent-1-yn-1-yl)phenyl)ethynyl)benzoate (1n)
1
Yielded 105 mg, 93%; A pale yellow oil; Rf = 0.4 (20:1 Hex/EtOAc); H NMR (400
MHz, CDCl3) δ 1.03 (t, J = 7.2 Hz, 3H), 1.64 (sext, J = 7.2 Hz, 2H), 2.47 (t, J = 7.2
Hz, 2H), 5.41 (s, 2H), 7.16-7.51 (m, 11H), 7.68 (d, J = 8.0 Hz, 1H), 8.02 (d, J = 8.0
Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 13.5, 21.7, 22.2, 67.0, 79.6, 91.5, 93.7, 94.8,
124.0, 125.6, 126.6, 127.1, 127.9, 128.0, 128.1, 128.3, 128.5, 130.6, 131.6, 131.7,
131.8, 132.0, 134.3, 135.8, 166.2; MS (70 eV) m/z (%): 378 (16) [M+], 335 (100);
HRMS (EI-magnetic sector) m/z: [M]+ Calcd for C27H22O2, 378.1620; Found,
378.1623.
Methyl 2-((2-iodophenyl)ethynyl)benzoate (3)
Yielded 2.97 g, 82%; A yellow oil; Rf = 0.2 (50:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 3.97 (s, 3H), 7.02 (td, J = 8.0, 1.6 Hz, 1H), 7.34 (td, J = 7.6, 1.2 Hz, 1H),
7.41 (td, J = 8.0, 1.6 Hz, 1H), 7.52 (td, J = 7.6, 1.2 Hz, 1H), 7.59 (dd, J = 8.0, 1.6 Hz,
13
1H), 7.76-7.78 (m, 1H), 7.86-7.88 (m, 1H), 7.98-8.00 (m, 1H); C NMR (100 MHz,
CDCl3) δ 52.3, 91.7, 96.2, 100.7, 123.3, 127.8, 128.2, 129.6, 129.8, 130.4, 131.6,

ACCEPTED MANUSCRIPT
131.7, 132.9, 134.2, 138.7, 166.6; MS (70 eV) m/z (%): 362.0 (3) [M+], 220.0 (5),
61.0 (100); HRMS (EI-magnetic sector) m/z: [M]+ Calcd for C16H11O2I, 361.9804;
Found, 361.9801.
11-Propyl-6H-dibenzo[c,h]chromen-6-one (4a)
1
Yielded 84.7 mg, 98%; A yellow solid; Rf= 0.4 (10:1 Hex/EtOAc); H NMR (400
MHz, CDCl3) δ 1.10 (t, J = 7.2 Hz, 3H), 1.86 (sext, J = 7.2 Hz, 2H), 3.28 (t, J = 7.6
Hz, 2H), 7.54-7.62 (m, 4H), 7.75-7.78 (m, 1H), 7.84 (td, J = 7.2, 1.6 Hz, 1H), 8.34 (d,
13
J = 8.4 Hz, 1H), 8.53 (dd, J = 8.0, 1.6 Hz, 1H), 8.55-8.58 (m, 1H); C NMR (100
MHz, CDCl3) δ 14.0, 23.6, 39.3, 113.2, 122.0, 122.5, 122.8, 126.0, 126.2, 126.3,
o
126.6, 128.0, 128.1, 130.8, 133.2, 134.4, 136.2, 136.4, 148.3, 161.1; mp 101-103 C;
MS (70 eV) m/z (%): 288.0 (56) [M+], 231.0 (34), 151.0 (100); HRMS (EI-magnetic
sector) m/z: [M]+ Calcd for C20H16O2, 288.1150; Found, 288.1151.
11-Pentyl-6H-dibenzo[c,h]chromen-6-one (4b)
1
Yielded 76.8 mg, 81%; A yellow solid; Rf= 0.4 (10:1 Hex/EtOAc); H NMR (400
MHz, CDCl3) δ 0.94 (t, J = 7.2 Hz, 3H), 1.37-1.54 (m, 4H), 1.85 (quin, J = 7.2 Hz,
2H), 3.33 (t, J = 7.6 Hz, 2H), 7.56-7.64 (m, 4H), 7.78-7.88 (m, 2H), 8.39 (d, J = 8.4
13
Hz, 1H), 8.56 (dd, J = 8.0, 1.6 Hz, 1H), 8.59-8.61 (m, 1H); C NMR (100 MHz,
CDCl3) δ 14.1, 22.5, 30.2, 31.9, 37.4, 113.3, 122.1, 122.6, 122.8, 126.1, 126.2, 126.4,
126.6, 128.0, 128.2, 130.8, 133.3, 134.4, 136.3, 136.8, 148.4 161.2; mp 90-92 oC; MS
(70 eV) m/z (%): 316.0 (93) [M+], 231.0 (61), 202.0 (29), 260.0 (100); HRMS
(EI-magnetic sector) m/z: [M]+ Calcd for C22H20O2, 316.1463; Found, 316.1465.
11-(4-Methoxyphenyl)-6H-dibenzo[c,h]chromen-6-one (4c)
1
Yielded 63.4 mg, 60%; A yellow solid; Rf= 0.2 (10:1 Hex/EtOAc); H NMR (400
MHz, CDCl3) δ 3.92 (s, 3H), 7.01-7.05 (m, 2H), 7.29 (d, J = 8.0 Hz, 1H), 7.34-7.41
(m, 3H), 7.46 (td, J = 7.2, 1.2 Hz, 1H), 7.59 (s, 1H), 7.60-7.66 (m, 2H), 7.81-7.85 (m,
1H), 8.45 (dd, J = 7.6, 1.6 Hz, 1H), 8.63-8.66 (m, 1H); 13C NMR (100 MHz, CDCl3)
δ 55.4, 112.6, 114.4, 122.0, 122.5, 123.2, 126.9, 127.0, 127.3, 127.3, 127.9, 128.4,
130.2, 130.3, 133.1, 133.5, 134.9, 135.7, 136.6, 159.3, 161.3; mp 197-199 oC; MS (70
eV) m/z (%): 352.0 (100) [M+], 252.0 (14), 186.0 (26); HRMS (EI-magnetic sector)
m/z: [M]+ Calcd for C24H16O3, 352.1099; Found, 352.1096.
11-(p-Tolyl)-6H-dibenzo[c,h]chromen-6-one (4d)
1
Yielded 85.7 mg, 85%; A yellow solid; Rf= 0.3 (10:1 Hex/EtOAc); H NMR (400
MHz, CDCl3) δ 2.49 (s, 3H), 7.26-7.34 (m, 5H), 7.37 (td, J = 7.2, 1.6 Hz, 1H), 7.46
(td, J = 7.2, 1.2 Hz, 1H), 7.59 (s, 1H), 7.59-7.66 (m, 2H), 7.81-7.84 (m, 1H), 8.45 (dd,

ACCEPTED MANUSCRIPT
13
J = 7.6, 1.2 Hz, 1H), 8.63-8.65 (m, 1H); C NMR (100 MHz, CDCl3) δ 21.3, 112.5,
121.9, 122.5, 123.2, 126.9, 127.0, 127.2, 127.3, 127.9, 128.4, 128.9, 130.0, 130.2,
o
133.0, 133.5, 135.6, 137.0, 137.6, 139.6, 148.2, 161.3; mp 197-199 C; MS (70 eV)
m/z (%): 336.0 (3) [M+], 296.0 (92), 161.0 (100); HRMS (EI-magnetic sector) m/z:
[M]+ Calcd for C24H16O2, 336.1150; Found, 336.1148.
11-(m-Tolyl)-6H-dibenzo[c,h]chromen-6-one (4e)
1
Yielded 92.7 mg, 92%; A orange solid; Rf = 0.3 (10:1 Hex/EtOAc); H NMR (400
MHz, CDCl3) δ 2.43 (s, 3H), 7.21-7.24 (m, 2H), 7.27-7.30 (m, 2H), 7.35-7.38 (m, 2H),
7.44-7.47 (m, 1H), 7.61-7.66 (m, 3H), 7.83-7.84 (m, 1H), 8.44-8.46 (m, 1H),
13
8.64-8.66 (m, 1H); C NMR (100 MHz, CDCl3) δ 21.5, 112.4, 121.9, 122.5, 123.2,
126.2, 127.0, 127.1, 127.1, 127.3, 128.0, 128.4, 128.5, 128.8, 129.6, 130.2, 133.0,
133.5, 135.6, 137.1, 138.8, 142.5, 148.1, 161.3; mp 181-183 oC; MS (70 eV) m/z (%):
336.0 (91) [M+], 321.0 (13), 149.0 (26) 61.0 (100); HRMS (EI-magnetic sector) m/z:
[M]+ Calcd for C24H16O2, 336.1150; Found, 336.1151.
11-(o-Tolyl)-6H-dibenzo[c,h]chromen-6-one (4f)
1
Yielded 75.6 mg, 75%; A yellow solid; Rf = 0.4 (10:1 Hex/EtOAc); H NMR (400
MHz, CDCl3) δ 1.99 (s, 3H), 7.14 (d, J = 8.0 Hz, 1H), 7.33-7.40 (m, 4H), 7.42 (dd, J
= 7.2, 2.4 Hz, 1H), 7.47 (td, J = 7.2, 0.8 Hz, 1H), 7.53 (s, 1H), 7.62-7.69 (m, 2H),
13
7.82-7.84 (m, 1H), 8.47 (dd, J = 7.6, 0.8 Hz, 1H), 8.67-8.70 (m, 1H); C NMR (100
MHz, CDCl3) δ 20.0, 112.7, 121.6, 122.6, 123.3, 125.1, 126.7, 126.8, 127.0, 127.2,
128.1, 128.3, 128.4, 129.3, 130.5, 130.5, 133.2, 134.3, 135.9, 136.1, 136.3, 142.1,
o
148.0, 161.2; mp 216-218 C; MS (70 eV) m/z (%): 336.0 (100) [M+], 321.0 (9),
291.0 (11); HRMS (EI-magnetic sector) m/z: [M]+ Calcd for C24H16O2, 336.1150;
Found, 336.1151.
11-Phenyl-6H-dibenzo[c,h]chromen-6-one (4g)
1
Yielded 84.0 mg, 87%; A orange solid; Rf = 0.3 (10:1 Hex/EtOAc); H NMR (400
MHz, CDCl3) δ 7.19 (d, J = 8.4 Hz, 1H), 7.35 (td, J = 7.2, 1.6 Hz, 1H), 7.42-7.52 (m,
6H), 7.61 (s, 1H), 7.63-7.68 (m, 2H), 7.82-7.86 (m, 1H), 8.45 (dd, J = 8.0, 1.6 Hz,
13
1H), 8.64-8.67 (m, 1H); C NMR (100 MHz, CDCl3) δ 112.4, 122.0, 122.6, 123.3,
127.0, 127.0, 127.2, 127.3, 127.8, 128.0, 128.4, 129.0, 129.1, 130.3, 133.0, 133.5,
o
135.5, 136.9, 142.5, 148.2, 161.2; mp 196-198 C; MS (70 eV) m/z (%): 322.0 (100)
[M+], 321.0 (22), 265.0 (22), 256.0 (19); HRMS (EI-magnetic sector) m/z: [M]+
Calcd for C23H14O2, 322.0994; Found, 322.0997.
11-(4-Chlorophenyl)-6H-dibenzo[c,h]chromen-6-one (4h)

ACCEPTED MANUSCRIPT
1
Yielded 90.8 mg, 85%;A yellow solid; Rf = 0.5 (10:1 Hex/EtOAc); H NMR (400
MHz, CDCl3) δ 7.23 (d, J = 8.0, 0.8 Hz, 1H), 7.38-7.51 (m, 6H), 7.57 (s, 1H),
7.62-7.69 (m, 2H), 7.82-7.85 (m, 1H), 8.46 (dd, J = 7.6, 0.4 Hz, 1H), 8.64-8.66 (m,
13
1H); C NMR (100 MHz, CDCl3) δ 112.1, 122.0, 122.6, 123.4, 126.8, 127.3, 127.3,
127.4, 128.1, 128.6, 129.3, 130.4, 130.5, 133.0, 133.6, 133.9, 135.3, 135.5, 141.0,
148.3, 161.1; mp 208-210 oC; MS (70 eV) m/z (%): 358.0 (2) [M+2], 356.0 (6) [M+],
61.0 (100); HRMS (EI-magnetic sector) m/z: [M]+ Calcd for C23H13O2Cl, 356.0604;
Found, 356.0604.
11-(4-Bromophenyl)-6H-dibenzo[c,h]chromen-6-one (4i)
1
Yielded 108 mg, 90%; A orange solid; Rf = 0.4 (10:1 Hex/EtOAc); H NMR (400
MHz, CDCl3) δ 7.24 (d, J = 8.0 Hz, 1H), 7.31-7.35 (m, 2H), 7.42 (td, J = 7.6, 2.0 Hz,
1H), 7.49 (td, J = 7.6, 1.2 Hz, 1H), 7.57 (s, 1H), 7.62-7.69 (m, 4H), 7.82-7.86 (m, 1H),
13
8.46 (dd, J = 7.6, 2.0 Hz, 1H), 8.64-8.66 (m, 1H); C NMR (100 MHz, CDCl3)
δ 112.1, 122.0, 122.1, 122.6, 123.4, 126.8, 127.3, 127.4, 128.2, 128.6, 130.5, 130.7,
o
132.2, 133.0, 133.7, 135.2, 135.5, 141.5, 148.3, 161.1; mp 232-234 C; MS (70 eV)
m/z (%):402.0 (88) [M+2], 401.0 (24) [M+], 304.0 (37), 263.0 (35), 57.0 (100);
HRMS (EI-magnetic sector) m/z: [M]+ Calcd for C23H13O2Br, 400.0099; Found,
400.0097.
11-(4-Ttrifluoromethyl)phenyl)-6H-dibenzo[c,h]chromen-6-one (4j)
Yielded 87.8 mg, 75%; A yellow oil; Rf = 0.4 (10:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 7.13 (d, J = 8.4 Hz, 1H), 7.40 (td, J = 7.6, 1.6 Hz, 1H), 7.49 (td, J = 8.0, 0.8
Hz, 1H), 7.60 (d, J = 7.2 Hz, 3H), 7.64-7.71 (m, 2H), 7.77 (d, J = 8.4 Hz, 2H),
13
7.85-7.87 (m, 1H), 8.47 (dd, J = 8.0, 1.6 Hz, 1H), 8.65-8.68 (m, 1H); C NMR (100
MHz, CDCl3) δ 29.7, 112.0, 122.0, 122.6, 123.6, 126.0, 126.0, 126.7, 127.5, 127.5,
128.3, 128.7, 129.5, 130.6, 133.0, 133.7, 135.0, 135.3, 146.3, 148.4, 161.0; MS (70
eV) m/z (%): 390.0 (20) [M+], 256.0 (17), 167.0 (100); HRMS (EI-magnetic sector)
m/z: [M]+ Calcd for C24H13O2F3, 390.0868; Found, 390.0865.
4-(6-Oxo-6H-dibenzo[c,h]chromen-11-yl)benzaldehyde (4k)
Yielded 88.2 mg, 84%; A yellow solid; Rf = 0.4 (5:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 7.13 (d, J = 8.4 Hz, 1H), 7.36 (td, J = 7.2, 1.6 Hz, 1H), 7.48 (td, J = 8.4, 1.2
Hz, 1H), 7.61 (s, 1H), 7.64-7.71 (m, 4H), 7.85-7.88 (m, 1H), 8.01-8.04 (m, 2H), 8.46
13
(dd, J = 7.6, 1.2 Hz, 1H), 8.65-8.67 (m, 1H), 10.15 (s, 1H); C NMR (100 MHz,
CDCl3) δ 111.9, 122.0, 122.6, 123.6, 126.8, 127.3, 127.5, 127.6, 128.3, 128.8, 129.9,
130.4, 130.6, 132.9, 133.6, 135.0, 135.4, 135.6, 148.4, 148.8, 161.0, 191.8; mp
192-194 oC; MS (70 eV) m/z (%): 350.0 (52) [M+], 296.0 (20), 161.0 (25), 57.0 (100);

ACCEPTED MANUSCRIPT
HRMS (EI-magnetic sector) m/z: [M]+ Calcd for C24H14O3, 350.0493; Found,
350.0496.
6H-Dibenzo[c,h]chromen-6-one (4m)
1
Yielded 29.5 mg, 40%; A yellow solid; Rf = 0.4 (10:1 Hex/EtOAc); H NMR (400
MHz, CDCl3) δ 7.60-7.66 (m, 3H), 7.79 (d, J = 9 Hz, 1H), 7.89-7.91 (m, 2H), 8.09 (d,
13
J = 8.7 Hz, 1H), 8.22 (d, J = 8.1 Hz, 1H), 8.48-8.51 (m, 1H), 8.60-8.63 (m, 1H); C
NMR (100 MHz, CDCl3) δ 113.0, 119.1, 121.2, 122.0, 122.3, 123.9, 124.5, 127.1,
127.7, 127.9, 128.6, 130.7, 134.3, 135.0, 135.4, 147.3, 161.2; mp 185-187 oC; MS (70
eV) m/z (%): 246.0 (80) [M+], 189.0 (28), 218.0 (20), 61.0 (100); HRMS
(EI-magnetic sector) m/z: [M]+ Calcd for C17H10O2, 246.0681; Found, 246.0680.
(Z)-Methyl 2-(nona-3-en-1,5-diyn-1-yl)benzoate (5a)
Yielded 142 mg, 62%; A yellow oil; Rf = 0.6 (10:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 1.02 (t, J = 7.6 Hz, 3H), 1.61 (sext, J = 7.2 Hz, 2H), 2.43 (td, J = 6.8, 2.0 Hz,
2H), 3.93 (s, 3H), 5.91 (dt, J = 10.8, 2.0 Hz, 1H), 6.04 (d, J = 10.8 Hz, 1H), 7.37 (td, J
= 8.0, 1.2 Hz, 1H), 7.47 (td, J = 7.6, 1.6 Hz, 1H), 7.59 (dd, J = 8.0, 1.2 Hz, 1H), 7.95
(dd, J = 8.0, 1.6 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 13.5, 21.9, 22.1, 52.1, 78.6,
92.1, 94.7, 99.5, 118.2, 120.9, 123.8, 128.0, 130.3, 131.6, 131.7, 134.4; MS (70 eV)
m/z (%): 252.0 (50) [M+], 208.0 (91), 209.0 (83), 224.0 (100); HRMS (EI-magnetic
sector) m/z: [M]+ Calcd for C17H16O2, 252.1152; Found, 252.1150.
(Z)-Methyl 2-(6-(4-methoxyphenyl)hexa-3-en-1,5-diyn-1-yl)benzoate (5b)
Yielded 148 mg, 52%; A yellow oil; Rf = 0.3 (10:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 3.82 (s, 3H), 3.88 (s, 3H), 6.12 (s, 2H), 6.85 (d, J = 9.0 Hz, 2H), 7.38 (td, J
= 7.8, 1.2 Hz, 1H), 7.44-7.50 (m, 3H), 7.64 (dd, J = 7.8, 0.9 Hz, 1H), 7.96 (dd, J = 6.9,
0.9 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 52.1, 55.3, 86.4, 92.3, 95.8, 98.1, 114.0,
115.2, 118.3, 120.3, 123.7, 128.1, 130.4, 131.7, 133.3, 134.4, 160.0, 166.6; MS (70
eV) m/z (%): 316.0 (100) [M+], 258.0 (22), 213.0 (38), 301.0 (100); HRMS
(EI-magnetic sector) m/z: [M]+ Calcd for C21H16O3, 316.1099; Found, 316.1099.
(Z)-Methyl 2-(6-(p-tolyl)hexa-3-en-1,5-diyn-1-yl)benzoate (5c)
Yielded 149 mg, 55%; A yellow oil; Rf = 0.4 (10:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 2.35 (s, 3H), 3.88 (s, 3H), 6.13 (s, 2H), 7.13 (d, J = 8.0 Hz, 2H), 7.36-7.42
(m, 3H), 7.47 (td, J = 7.6, 1.2 Hz, 1H), 7.64 (d, J = 7.6 Hz, 1H), 7.96 (dd, J = 7.6, 1.2
13
Hz, 1H); C NMR (100 MHz, CDCl3) δ 21.5, 52.1, 86.8, 92.1, 95.9, 98.1, 118.9,
120.0, 120.2, 123.6, 128.1, 129.1, 130.4, 131.6, 131.7, 134.4, 138.9, 166.5; MS (70
eV) m/z (%): 300.0 (100) [M+], 285.0 (40), 270.0 (23), 226.0 (23); HRMS

ACCEPTED MANUSCRIPT
(EI-magnetic sector) m/z: [M]+ Calcd for C21H16O2, 300.1150; Found, 300.1151.
(Z)-Methyl 2-(6-phenylhexa-3-en-1,5-diyn-1-yl)benzoate (5d)
1
Yielded 165 mg, 64%; A yellow solid; Rf = 0.3 (10:1 Hex/EtOAc); H NMR (400
MHz, CDCl3) δ 3.88 (s, 3H), 6.15 (q, J = 10.8 Hz, 2H), 7.31-7.34 (m, 3H), 7.38 (td, J
= 7.6, 1.2 Hz, 1H), 7.47 (td, J = 7.6, 1.2 Hz, 1H), 7.51-7.54 (m, 2H), 7.65 (dd, J = 8.0,
1.6 Hz, 1H), 7.97 (dd, J = 7.6, 1.2 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 52.1, 87.3,
92.0, 96.1, 97.7, 119.4, 120.0, 123.1, 123.6, 128.2, 128.3, 128.6, 130.4, 131.7, 131.8,
o
134.4, 166.5; mp 47-49 C; MS (70 eV) m/z (%): 286.0 (43) [M+], 213.0 (27), 165.0
(59), 89.0 (100); HRMS (EI-magnetic sector) m/z: [M]+ Calcd for C20H14O2,
286.0994; Found, 286.0996.
(Z)-Methyl 2-(6-(4-chlorophenyl)hexa-3-en-1,5-diyn-1-yl)benzoate (5e)
Yielded 187 mg, 65%; A yellow oil; Rf = 0.4 (10:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 3.88 (s, 3H), 6.11 (d, J = 10.8 Hz, 1H), 6.19 (d, J = 10.8 Hz, 1H), 7.26-7.31
(m, 2H), 7.40 (td, J = 7.6, 1.6 Hz, 1H), 7.44-7.50 (m, 3H), 7.63 (dd, J = 8.0, 1.2 Hz,
13
1H), 7.97 (dd, J = 8.0, 0.8 Hz, 1H); C NMR (100 MHz, CDCl3) δ 52.1, 88.2, 91.9,
96.3, 96.4, 119.6, 119.9, 121.6, 123.5, 128.3, 128.7, 130.4, 131.7, 133.0, 134.4, 134.7,
166.4; MS (70 eV) m/z (%): 322.0 (40) [M+2], 320.0 (100) [M+], 305.0 (34), 270.0
(45); HRMS (EI-magnetic sector) m/z: [M]+ Calcd for C20H13O2Cl, 320.0604; Found,
320.0607.
(Z)-Methyl 2-(6-(4-bromophenyl)hexa-3-en-1,5-diyn-1-yl)benzoate (5f)
Yielded 196 mg, 60%; A yellow oil; Rf = 0.5 (10:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 3.88 (s, 3H), 6.10 (d, J = 10.8 Hz, 1H), 6.19 (d, J = 10.8 Hz, 1H), 7.37-7.50
(m, 6H), 7.62 (dd, J = 8.0, 0.8 Hz, 1H), 7.97 (dd, J = 7.6, 0.8 Hz, 1H); 13C NMR (100
MHz, CDCl3) δ 52.1, 88.4, 91.9, 96.4, 96.5, 119.6, 119.9, 122.1, 122.9, 123.5, 128.3,
130.4, 131.6, 131.6, 131.7, 133.2, 134.4, 166.4; MS (70 eV) m/z (%): 366.0 (100)
[M+2], 364.0 (97) [M+], 351.0 (22), 270.0 (95); HRMS (EI-magnetic sector) m/z:
[M]+ Calcd for C20H13O2Br, 364.0099; Found, 364.0098.
(Z)-Methyl 2-(6-(4-(trifluoromethyl)phenyl)hexa-3-en-1,5-diyn-1-yl)benzoate (5g)
1
Yielded 194 mg, 69%; A yellow solid; Rf = 0.3 (10:1 Hex/EtOAc); H NMR (400
MHz, CDCl3) δ 3.87 (s, 3H), 6.13 (d, J = 10.8 Hz, 1H), 6.24 (d, J = 10.8 Hz, 1H),
7.40 (td, J = 7.6, 1.2 Hz, 1H), 7.49 (td, J = 7.6, 1.6 Hz, 1H), 7.56-7.65 (m, 5H), 7.98
(dd, J = 7.6, 1.2 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 52.1, 89.4, 91.7, 95.9, 96.7,
119.3, 120.8, 123.4, 125.2, 125.2, 125.2, 125.3, 126.9, 128.4, 130.4, 130.5, 131.7,
o
131.7, 132.0, 134.4, 166.4; mp 57-59 C; MS (70 eV) m/z (%): 354.0 (100) [M+],

ACCEPTED MANUSCRIPT
339.0 (41), 311.0 (21), 283.0 (29); HRMS (EI-magnetic sector) m/z: [M]+ Calcd for
C21H13O2F3, 354.0868; Found, 354.0867.
(Z)-Methyl 2-(6-(4-formylphenyl)hexa-3-en-1,5-diyn-1-yl)benzoate (5h)
Yielded 193 mg, 68%; A yellow solid; Rf = 0.4 (5:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 3.88 (s, 3H), 6.15 (d, J = 10.8 Hz, 1H), 6.26 (d, J = 10.8 Hz, 1H), 7.41 (td, J
= 8.0, 1.6 Hz, 1H), 7.50 (td, J = 7.2, 1.2 Hz, 1H), 7.63-7.70 (m, 3H), 7.83-7.86 (m,
2H), 7.98 (dd, J = 7.6, 0.8 Hz, 1H), 10.0 (s, 1H); 13C NMR (100 MHz, CDCl3) δ 52.1,
91.1, 91.7, 96.4, 97.0, 119.2, 121.1, 123.4, 128.5, 129.4, 129.5, 129.6, 130.5, 131.7,
o
131.8, 132.3, 134.4, 135.6, 166.3, 191.4; mp 70-72 C; MS (70 eV) m/z (%): 314.0
(100) [M+], 299.0 (21), 226.0 (27), 213.0 (32); HRMS (EI-magnetic sector) m/z: [M]+
Calcd for C21H14O3, 314.0943; Found, 314.0946.
1-Propyl-6H-benzo[c]chromen-6-one (6a)
Yielded 61 mg, 73%; A yellow solid; Rf = 0.6 (10:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 1.11 (t, J = 7.2 Hz, 3H), 1.84 (sext, J = 7.2 Hz, 2H), 3.17 (m, 2H), 7.19 (dd,
J = 7.6, 1.6 Hz, 1H), 7.28 (dd, J = 8.0, 1.6 Hz, 1H), 7.38 (t, J = 8.0 Hz, 1H), 7.60 (td,
J = 7.2, 1.2 Hz, 1H), 7.84 (td, J = 7.2, 1.6 Hz, 1H), 8.25 (d, J = 8.4 Hz, 1H), 8.50 (dd,
13
J = 8.0, 1.6 Hz, 1H); C NMR (100 MHz, CDCl3) δ 14.1, 23.4, 38.8, 116.3, 117.0,
122.2, 126.0, 128.0, 128.1, 129.4, 130.9, 134.4, 135.6, 140.9, 152.3, 161.3; mp 82-84
oC; MS (70 eV) m/z (%): 238.0 (75) [M+], 209.0 (28), 152.0 (25), 165.0 (100); HRMS
(EI-magnetic sector) m/z: [M]+ Calcd for C16H14O2, 238.0994; Found, 238.0993.
1-(4-Methoxyphenyl)-6H-benzo[c]chromen-6-one (6b)
Yielded 44 mg, 42%; A white solid; Rf = 0.3 (10:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 3.91 (s, 3H), 6.99-7.03 (m, 2H), 7.14 (dd, J = 7.6, 1.6 Hz, 1H), 7.23 (d, J =
8.4 Hz, 1H), 7.25-7.29 (m, 2H), 7.33-7.39 (m, 2H), 7.41-7.47 (m, 2H), 8.38 (dd, J =
13
8.0, 1.2 Hz, 1H); C NMR (100 MHz, CDCl3) δ 55.4, 114.6, 116.5, 116.9, 122.1,
126.7, 128.1, 128.5, 129.1, 129.9, 130.3, 133.5, 134.5, 135.1, 140.7, 152.0, 159.4,
161.3; mp 158-160 oC; MS (70 eV) m/z (%): 302.0 (95) [M+], 301.0 (34), 215.0 (19),
202.0 (29); HRMS (EI-magnetic sector) m/z: [M]+ Calcd for C20H14O3, 302.0943;
Found, 302.0940.
1-(p-Tolyl)-6H-benzo[c]chromen-6-one (6c)
Yielded 72 mg, 72%; A white solid; Rf = 0.4 (10:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 2.47 (s, 3H), 7.14 (dd, J = 7.2, 1.2 Hz, 1H), 7.19-7.29 (m, 5H), 7.32-7.36 (m,
13
1H), 7.37-7.41 (m, 1H), 7.43-7.47 (m, 2H), 8.38 (dd, J = 8.0, 1.6 Hz, 1H); C NMR
(100 MHz, CDCl3) δ 21.3, 116.4, 117.0, 122.1, 126.8, 128.1, 128.4, 128.6, 129.1,

ACCEPTED MANUSCRIPT
129.8, 130.3, 133.5, 135.1, 137.7, 139.3, 141.0, 152.0, 161.3; mp 133-135 oC; MS (70
eV) m/z (%): 286.0 (100) [M+], 271.0 (63), 226.0 (20); HRMS (EI-magnetic sector)
m/z: [M]+ Calcd for C20H14O2, 286.0994; Found, 286.0994.
1-Phenyl-6H-benzo[c]chromen-6-one (6d)
Yielded 76 mg, 80%; A white solid; Rf = 0.3 (10:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 7.12 (dt, J = 8.0, 0.4 Hz, 1H), 7.16 (dd, J = 7.2, 1.2 Hz, 1H), 7.29-7.50 (m,
13
9H), 8.38-8.40 (m, 1H); C NMR (100 MHz, CDCl3) δ 116.4, 117.2, 122.2, 126.8,
128.0, 128.2, 128.2, 128.8, 129.2, 130.4, 133.5, 134.9, 141.0, 142.3, 152.0; mp
o
156-158 C; MS (70 eV) m/z (%): 272.0 (100) [M+], 271.0 (59), 215.0 (33), 213.0
(20); HRMS (EI-magnetic sector) m/z: [M]+ Calcd for C19H12O2, 272.0837; Found,
272.0840.
1-(4-Chlorophenyl)-6H-benzo[c]chromen-6-one (6e)
Yielded 86 mg, 80%; A white solid; Rf = 0.4 (10:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 7.12 (dd, J = 7.6, 1.6 Hz, 1H), 7.17 (d, J = 8.4 Hz, 1H), 7.30-7.33 (m, 2H),
13
7.37-7.49 (m, 6H), 8.40 (dd, J = 7.6, 1.2 Hz, 1H); C NMR (100 MHz, CDCl3)
δ 116.4, 117.5, 122.2, 126.6, 128.2, 128.4, 129.3, 129.4, 130.2, 130.5, 133.6, 134.1,
o
134.6, 139.5, 140.7, 152.1, 161.0; mp 130-132 C; MS (70 eV) m/z (%): 308.0 (27)
[M+2], 306.0 (69) [M+], 271.0 (35), 213.0 (27), 61.0 (100); HRMS (EI-magnetic
sector) m/z: [M]+ Calcd for C19H11O2Cl, 306.0448; Found, 306.0445.
1-(4-Bromophenyl)-6H-benzo[c]chromen-6-one (6f)
Yielded 120 mg, 98%; A white solid; Rf = 0.5 (10:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 7.12 (dd, J = 7.6, 1.6 Hz, 1H), 7.18 (d, J = 8.4 Hz, 1H), 7.24-7.27 (m, 2H),
7.37-7.43 (m, 2H), 7.45-7.49 (m, 2H), 7.60-7.64 (m, 2H), 8.40 (dd, J = 8.0, 2.0 Hz,
13
1H); C NMR (100 MHz, CDCl3) δ 116.3, 117.6, 122.2, 126.6, 128.2, 128.5, 129.3,
o
130.5, 130.5, 132.4, 133.7, 134.6, 139.5, 141.2, 152.1; mp 140-142 C; MS (70 eV)
m/z (%): 272.0 (4) [M+2], 271.0 (4) [M+], 61 (100); HRMS (EI-magnetic sector) m/z:
[M]+ Calcd for C19H11O2Br, 349.9942; Found, 349.9944.
1-(4-(Trifluoromethyl)phenyl)-6H-benzo[c]chromen-6-one (6g)
Yielded 68 mg, 57%; A white solid; Rf = 0.3 (10:1 Hex/EtOAc); 1H NMR (400 MHz,
CDCl3) δ 7.06 (d, J = 8.4 Hz, 1H), 7.13 (dd, J = 7.2, 1.6 Hz, 1H), 7.36 (td, J = 7.6, 1.6
Hz, 1H), 7.43-7.53 (m, 5H), 7.76 (d, J = 8.0 Hz, 2H), 8.41 (dd, J = 7.6, 1.2 Hz, 1H);
13C NMR (100 MHz, CDCl3) δ 116.3, 117.9, 122.3, 126.1, 126.1, 126.2, 126.2, 126.5,
128.1, 128.6, 129.3, 129.4, 130.6, 133.7, 134.4, 139.2, 146.0, 152.1, 161.0; mp
o
172-174 C; MS (70 eV) m/z (%): 340.0 (100) [M+], 339.0 (43), 283.0 (21), 271.0

ACCEPTED MANUSCRIPT
(24); HRMS (EI-magnetic sector) m/z: [M]+ Calcd for C20H11O2F3, 340.0711; Found,
340.0713.
4-(6-Oxo-6H-benzo[c]chromen-1-yl)benzaldehyde (6h)
1
Yielded 80 mg, 76%; A white solid; Rf = 0.3 (5:1 Hex/EtOAc); H NMR (400 MHz,
CDCl3) δ 7.07 (d, J = 8.4 Hz, 1H), 7.15 (dd, J = 7.2, 1.2 Hz, 1H), 7.31-7.35 (m, 1H),
7.44-7.53 (m, 3H), 7.56-7.58 (m, 2H), 8.00-8.03 (m, 2H), 8.41 (dd, J = 8.0, 1.6 Hz,
13
1H), 10.1 (s, 1H); C NMR (100 MHz, CDCl3) δ 116.3, 118.0, 122.3, 126.6, 127.9,
128.6, 129.4, 129.7, 130.5, 130.6, 133.6, 134.3, 135.8, 139.4, 148.6, 152.1, 191.7; mp
150-152 oC; MS (70 eV) m/z (%): 300.0 (91) [M+], 272.0 (35), 215.0 (41), 57.0 (100);
HRMS (EI-magnetic sector) m/z: [M]+ Calcd for C20H12O3, 300.0786; Found,
300.0785.
Acknowledgment
We thank the Ministry of Science and Technology of the Republic of China for
financial support.
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