Convenient synthesis of O-functionalized mandelic acids via Lewis acid mediated transformation of 1,3-dioxolan-4-ones

Article abstract of DOI:10.1016/j.tet.2019.05.025

An efficient method for the synthesis of O-substituted mandelic acids containing alkenyl, alkynyl, methoxycarbonyl, or phenacyl fragments via the Lewis acid-catalyzed reaction of 1,3-dioxolan-4-ones with different C-nucleophiles is proposed.

Full text of DOI:10.1016/j.tet.2019.05.025

Tetrahedron 75 (2019) 3570e3578
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Convenient synthesis of O-functionalized mandelic acids via Lewis
acid mediated transformation of 1,3-dioxolan-4-ones
Vitaly A. Shcherbinin, Valery V. Konshin*
Department of Chemistry and High Technology, Kuban State University, Stavropolskaya st. 149, Krasnodar 350040, Russian Federation
a r t i c l e i n f o
a b s t r a c t
Article history:
An efficient method for the synthesis of O-substituted mandelic acids containing alkenyl, alkynyl,
methoxycarbonyl, or phenacyl fragments via the Lewis acid-catalyzed reaction of 1,3-dioxolan-4-ones
with different C-nucleophiles is proposed.
Received 13 February 2019
Received in revised form
6 May 2019
Accepted 11 May 2019
Available online 17 May 2019
© 2019 Elsevier Ltd. All rights reserved.
Keywords:
1,3-Dioxolan-4-one
Oxocarbenium cation
C-nucleophile
1-Alkyne
1. Introduction
products depending on the nature of the nucleophile used. In the
present work, we developed this research trend as applied to the
The structural motif of O-substituted mandelic acid occurs in
many bioactive compounds; for example, compound 1 and Man-
dipropamid (4) possess antifungicidal activity [1], derivatives of O-
methylated mandelic acid 2 possess growth-regulating activity [2],
synthesis of O-substituted mandelic acids.
2. Results and discussion
compound 3 is a potential PPAR a/g agonist for the treatment of
type 2 diabetes [3], and mandelic acid hydrazide 5 is a selective
inhibitor of phosphodiesterase 10A (Fig. 1) [4].
The most common methods for the preparation of O-substituted
mandelic acids can be divided into several main types: a) oxidative
transformations of a-functionalized O-substituted benzyl alcohols
[5]; b) O-functionalization of mandelic acids [6]; c) rhodium-
catalyzed transformations of 2-diazophenylacetic acids [7]; and d)
the reaction n of 1,3-dioxolan-4-ones (also referred to as Seebach
chiral templates) [8] with different nucleophiles (Fig. 2) [9].
Among methods for the preparation O-substituted mandelic
acids, those using 1,3-dioxolan-4-ones are, in our opinion, most
promising, but are associated with the use of organometallic re-
agents and the need to perform reactions on cooling to ꢀ78 ꢁC. At
the same time, in the short communication [10] we have shown
that the reaction between 1,3-dioxolan-4-ones and different C-
nucleophilic reagents can afford both mono- and bis-addition
There are several protocols for the synthesis of 1,3-dioxolan-4-
ones based on the condensation of carbonyl compounds with a-
hydroxycarboxylic acids in the presence of mineral acids [11].
However, the modified procedure [12] based on the use of BF3$OEt2
as a catalyst in the acetonitrile medium is, in our opinion, the most
convenient and applicable for a wide range of substrates (Table 1).
Using this procedure, we obtained the corresponding 1,3-dioxolan-
4-ones in reasonable yields from commercially available racemic
and optically pure mandelic acid (Entry 1), and 4-fluoro-, 4-
fluoromethyl-, 4-bromomandelic acids (Examples 5e7).
The exact configuration of compound 3a was determined by X-
ray diffraction which showed both stereoisomers to have cis
configuration (Fig. 3).
Such Lewis acids as TiCl4 and BF3$OEt2 have been used earlier as
catalysts for the reactions of 1,3-dioxolan-4-ones with silicon-
containing nucleophiles and found to be efficient when the reac-
tion was performed at very low temperatures [9]. At the same time,
FeCl3 is known to exhibit excellent catalytic activity in the reactions
of acetals with allylsilanes and silyl ketene acetals and is also effi-
cient in an amount of 5e10 mol. % in room-temperature reactions
[13]. Therefore, first we studied the reactions of 1,3-dioxolan-4-
* Corresponding author.
E-mail address: organotin@mail.ru (V.V. Konshin).
https://doi.org/10.1016/j.tet.2019.05.025
0040-4020/© 2019 Elsevier Ltd. All rights reserved.

V.A. Shcherbinin, V.V. Konshin / Tetrahedron 75 (2019) 3570e3578
3571
Fig. 3. Crystal structure of compound 3a with labeling schemes and 50% thermal
ellipsoids.
Fig. 1. Examples of bioactive compounds containing the O-substituted mandelic acid
moiety.
30 min and the preparative-scale yield of substituted mandelic
acids 5a-d in this case reaches 84% (Entry 1e4). In the case of tert-
butyl-substituted 1,3-dioxolan-4-one 3d, the complete conversion
of the reagents requires keeping the reaction mixture for 24 h at
room temperature (Entry 5). Methallyltrimethylsilane 4b also af-
fords the corresponding substituted mandelic acid in yield of 78%
(Entry 6).
The experiment on allylation of 1,3-dioxolan-4-one S-3a pre-
pared from (S)-(þ)-mandelic acid showed that, in this case, there is
no difference in the diastereomeric ratio of products compared to
the use of 1,3-dioxolan-4-one 3a prepared from racemic mandelic
acid (Fig. 4). This fact is indirect evidence that the reaction proceeds
through the intermediate formation of the planar oxocarbenium
cation shown in Fig. 6.
The reactions of 1,3-dioxolan-4-ones with silyl ketene acetal 4c
also proceeds readily at room temperature (Entry 7e9). The reac-
tion of 3a with silylenol 4d (Entry 10) requires cooling of the re-
action mixture to ꢀ10ꢁ, since a mixture of products, which is
difficult to separate, is produced at room temperature according to
the data from TLC. The formation of a mixture of diastereomers,
whose ratio was determined by 1H NMR spectroscopy, was
observed in all cases. In some of examples, we succeeded in
preparative-scale isolation of diastereomers by flash chromatog-
raphy on silica gel (in the case of 5a,f,j and 7c).
Fig. 2. Main methods for the preparation of O-substituted mandelic acids.
Table 1
Synthesis of 1,3-dioxalan-4-ones 3a-g.a
The crystal structure of major diastereomer of compound 5f is
shown on Fig. 5. This product corresponds to the attack of the
metalylsilane 4b to the oxocarbenium cation 8 (see Fig. 6) from the
side opposite to the carboxyl group, as it is less sterically hindered.
In the case when the nucleophile was vinyltrimethylsilane or
(phenylethynyl)trimethylsilane, no formation of reaction product
was detected.
It is known that activation of not only substrate, but also
nucleophile is used in order to generate electrophilic species. For
example, activation through the formation of corresponding metal
acetylides is often used for 1-alkynes whose nucleophilicity on the
Mayr scale [14] is considerably lower than that of silicon-containing
nucleophiles 4a-d. A convenient technique was applied earlier by
Carreira [15] and Downey [16a] to activate 1-alkynes in the re-
actions with carbonyl compounds and by Watson [16b] for the
reactions with acetals, which consisted in generation of zinc or
copper acetyldies in the presence of ZnBr2 or CuI and DIPEA.
The use of this methodology in combination with TMSOTf to
generate the oxocarbenium cation from 1,3-dioxolan-4-ones 3a-g
allowed us to obtain alkynylation products 7a-k (Table 3).
Arylalkynes 6a-d with both donor and acceptor substituents, as
well as trimethylsilylacetylene 6e undergo this reaction. As Table 2
shows, the presence of the electron-donating substituent in 1-
alkyne (Entry 9) increases the reaction time and decreases the
Entry
R [1]
R [2]
Yieldb,d (%)
1
2
3
4
5
6
7
3a
3b
3c
3d
3e
3f
H
H
H
H
F
CF3
Br
Ph
59 (56)c
72
48
57
64
p-NO2Ph
p-BrPh
t-Bu
Ph
Ph
Ph
71
59
3g
a
The reaction was performed using racemic mandelic acid 1a-d (15 mmol) and
aldehyde 2 (10 mmol) in acetonitrile (30 mL) in the presence of BF3$OEt2 (15 mmol)
in an argon atmosphere at 0 ꢁC.
b
Yield after recrystallization.
The yield in parentheses is given for 1,3-dioxolan-4-one S-3a obtained from (S)-
c
(þ)-mandelic acid.
d
The ratio of cis/trans-isomers was 91:9 for S-3a, 68:32 for 3b, 86:14 for 3e, 74:26
for 3f, 75:25 for 3g, and >99:1 for compounds 3a, 3c and 3d (according to the NMR
data).
ones 1 with different silicon-containing nucleophiles 4 in the
presence of 10 mol. % FeCl3 (Table 2).
The reaction of 1,3-dioxolan-4-ones 3a,e-g with allyl-
trimethylsilane 4a proceeds smoothly at room temperatures; ac-
cording to the GC/MS data, the reagents are consumed within

3572
V.A. Shcherbinin, V.V. Konshin / Tetrahedron 75 (2019) 3570e3578
Table 2
Reaction of 1,3-dioxolan-4-ones 3a,d-g with silicon-containing nucleophiles 4a-d.a
Entry
Nucleophile
Product
Time (h)
0.5
Yieldb (%)
Entry
Nucleophile
Product
Time (h)
1.5
Yieldb (%)
78 (68:32)
1
84 (62:38)c
6
2
3
0.5
0.5
62 (61:39)
82 (57:43)
7
8
2
2
63 (64:36)b
53 (73:27)
4
0.5
80 (55:45)
9
2
66 (74:26)
5
24
76 (76:24)
10
1
55d (61:39)
a
The reaction was carried out using dioxolan-4-one (0.60 mol) in CH2Cl2 (5.5 mL), nucleophile (0.90 mol in the case of 5a-f, 0.66 mol in the case of 5g-i, or 0.60 mol in the
case of 5j), and FeCl3 (0.06 mol) in an argon atmosphere at r.t.
b
Yield of pure products (the ratio of diastereomers is given in parentheses).
Ratio of diastereomers according to NMR spectra.
The reaction was carried out at ꢀ10 ꢁC.
c
d
stabilization of the oxocarbenium intermediate in this case.
In all cases, the reaction products form as a mixture of di-
astereomers in a ratio from 1 : 1.5 to 1 : 4. We assign this to the
assumption of that the intermediate oxocarbenium cation 8 has a
planar structure and can be attacked by a nucleophile on either
side; however, steric hindrances created by substituents make one-
side attack more preferred. To confirm this assumption, we per-
formed quantum chemical calculations of the oxocarbenium in-
Fig. 4. Allylation of the optical isomer S-3a.
termediate 8, which showed its planar structure (Fig. 6).
product yield to 45%, which is likely due to a lower acidity of
methoxyphenylacetylene 6c and, consequently, a slower formation
of acetylide. Also, an increase in the reaction time along with a
decrease in the product yield is observed upon introduction of an
electron-withdrawing substituent to the starting dioxalanone 3b
(Entry 6) or replacement of the benzene ring with the tert-butyl
group in 3d (Entry 7). This fact can be explained by a worse
3. Conclusion
Thus, we have proposed a simple method for the preparation of
O-functionalized mandelic acids containing alkenyl, alkynyl,
methoxycarbonyl, or phenacyl fragments via the Lewis acid-
catalyzed reaction between 1,3-dioxolan-4-ones and different C-
nucleophiles.

V.A. Shcherbinin, V.V. Konshin / Tetrahedron 75 (2019) 3570e3578
3573
without further purification.
4.2. A typical procedure for synthesis of 2,5-diphenyl-1,3-dioxolan-
4-one (3a)
To a stirring solution of 4 g (26 mmol) D,L-mandelic acid and
1,75 mL (17.3 mmol) benzaldehyde in 80 mL ACN at 0ꢁС in an argon
atmosphere, was added 3,33 mL (26 mmol) BF3$OEt2. The reaction
mixture was stirred for 3 h at 0ꢁС, poured to saturated sodium
carbonate solution and extracted DCM. The organic phase was
washed consistently with saturated sodium carbonate solution and
distilled water, dried with anhydrous Na2SO4 and evaporated. The
residue was recrystallized from 110 mL i-octane. Yield of 3a 2.21 g
(53%) as a colourless crystals, mp 100e101ꢁС. 1H NMR (600 MHz,
CDCl3): 7.60e7.61 (m, 2H, HAr), 7.49e7.52 (m, 5H, HAr), 7.41e7.45
(m, 3H, HAr), 6.58 (s, 1H, CH), 5.44 (s, 1H, CH) ppm. 13C NMR
(151 MHz, CDCl3)
d 171.45, 134.4, 133.4, 130.9, 129.5, 129.0 (2C),
Fig. 5. Crystal structure of major diastereomer of compound 5f with labeling schemes
and 50% thermal ellipsoids.
128.9 (2C), 127.1 (2C), 126.9 (2C), 103.4, 77.4 ppm. IR: 1784, 1398,
1331, 1221, 1207, 1192, 1055, 748, 694 cmꢀ1. MS (EI, 70 eV) m/z: 196
([Mþ ꢀ 44], 100%); 195 (49); 167 (97); 105 (80); 90 (61); 89 (61); 77
(68).
4.2.1. (2S,5S)-2,5-Diphenyl-1,3-dioxolan-4-one (S-3a)
Colourless crystals, mp 88e89ꢁС (i-octane). 1H NMR (400 MHz,
CDCl3): 7.59e7.62 (m, 2H, HAr), 7.41e7.53 (m, 9H, HAr), 6.70 (s, 0.1H,
CH, minor), 6.58 (d, J ¼ 0.4 Hz, 1H, CH, major), 5.53 (s, 0.1H, CH,
minor), 5.43 (s, 1H, CH, major) ppm. 13C NMR (151 MHz, CDCl3)
d
171.4, 134.4, 133.5, 130.9, 129.5, 129.0 (2C), 128.9 (2C), 127.1 (2C),
126.9 (2C), 103.4, 77.4 ppm. IR: 1784, 1396, 1329, 1221, 1192, 1055,
750, 694 cmꢀ1. MS (EI, 70 eV) m/z: 196 ([Mþ ꢀ 44], 100%); 195 (50);
167 (75); 105 (68); 90 (42); 89 (40); 77 (53).
The products 3c-g were prepared by the similar procedure.
4.2.2. 2-(4-Bromophenyl)-5-phenyl-1,3-dioxolan-4-one (3c)
Colourless crystals, mp 105e106ꢁС (MeOtBu:Hex). 1H NMR
(400 MHz, CDCl3): 7.60e7.64 (m, 2H, HAr), 7.41e7.49 (m, 7H, HAr),
6.53 (d, J ¼ 0.4 Hz, 1H, CH), 5.42 (d, J ¼ 0.4 Hz, 1H, CH) ppm. 13C NMR
Fig. 6. Computed structure of the oxocarbenium intermediate 8 optimazed at the
RB3LYP level with 6-31 þ G basis set in toluene.
(101 MHz, CDCl3)
d 171.1, 133.5, 133.2, 132.2 (2C), 129.6, 129.0 (2C),
128.5 (2C), 127.1 (2C), 125.2, 102.6, 77.3 ppm. IR: 1792, 1217, 1196,
1178, 1063, 1011, 827, 762, 698 cmꢀ1. MS (EI, 70 eV) m/z: 276 ([Mþ,
81Br]-44, 43%); 274 ([Mþ, 79Br]-44, 43%); 195 (78); 90 (51); 89
(100); 77 (66); 51 (40).
4. Experimental section
4.1. General information
4.2.3. 2-(tert-butyl)-5-phenyl-1,3-dioxolan-4-one (3d)
Reactions were monitored by GC-2010 (Shimadzu) with mass-
selective detector QP-2010 Plus (Shimadzu): Supelko SLB-5ms
column, 30 m, programmable heating from 60 to 265ꢁС 30 оС/
min and thin layer chromatography (TLC). Column chromatography
Colourless crystals, mp 109e110ꢁС (i-octane). 1H NMR
(400 MHz, CDCl3): 7.39e7.48 (m, 5H, HAr), 5.32 (d, J ¼ 0.8 Hz, 1H,
CH), 5.24 (s, 1H, CH) ppm. 13C NMR (101 MHz, CDCl3)
d 172.0, 133.7,
was performed using Silica 60 (40e63 m
m, Mecherey-Nagel). 1H
129.3, 128.9 (2C), 127.2 (2C), 109.5, 77.2, 34.6, 23.8 (3C) ppm. IR:
2980, 2959, 1800, 1776, 1275, 1207, 1184, 976, 760, 696 cmꢀ1. MS (EI,
70 eV) m/z: 176 ([Mþ ꢀ 44], 52%); 135 (77); 107 (100); 79 (52); 70
(98); 57 (72); 41 (43).
NMR and 13C NMR spectra were acquired on an ECA400 (JEOL) (400
and 100 MHz, respectively) and BRUKER AVANCE-600 (600 and
150 MHz, respectively) spectrometers in CDCl3 at room tempera-
ture. Chemical shifts
to the residual solvent resonances ([1]Н: CDCl3,
CDCl3,
d were measured in ppm and were referenced
d
¼ 7.26 ppm, 13C:
4.2.4. 5-(4-Fluorophenyl)-2-phenyl-1,3-dioxolan-4-one (3e)
d
¼ 77.2 ppm). Splitting patterns are designated as s, singlet;
Colourless crystals, mp 90e91ꢁС (i-octane). 1H NMR (400 MHz,
CDCl3): 7.56e7.59 (m, 2H, HAr), 7.46e7.52 (m, 5H, HAr), 7.10e7.15
(m, 2H, HAr), 6.69 (s, 0.16H, CH, minor), 6.57 (s, 1H, CH, major), 5.48
(s, 0.16H, CH, minor), 5.41 (s, 1H, CH, major) ppm. 13C NMR
d, doublet; t, triplet; m, multiplet; dd, double doublet. Coupling
constants (J) are given in Hertz. IR spectra were recorded on a IR
Prestige (Shimadzu) for tablets of samples with potassium bromide
or for chloroform solution. Mass spectra were recorded on a
GCMSꢀQP2010 Plus Shimadzu, EI ionization (70 eV, ionization
chamber temperature 250ꢁС). The procedure of preliminary
derivatization to the corresponding ethyl esters described previ-
ously was used for compounds 5a-i and 7a-k [17]. Melting points
were determined on an Stuart SMP30 apparatus and are uncor-
rected. All chemicals used were of commercial grade and were used
(101 MHz, CDCl3)
d
171.2, 171.1, 163.4 (d, J1 ¼ 247.1 Hz, major),
C-F
163.3 (d, J1 ¼ 247.1 Hz, minor), 135.1, 134.3, 131.0, 130.7, 129.3 (d,
C-F
J3 ¼ 3.1 Hz, major þ minor), 129.1 (2C), 129.0 (2C), 128.2 (d, J2
C-F
C-
¼ 8.4 Hz, major þ minor), 126.9, 126.4, 116.3, 116.14, 116.08, 115.9,
F
103.8, 103.4, 76.7, 74.9 ppm. IR: 2920, 1802, 1510, 1402, 1226, 1186,
1059, 837 cmꢀ1. MS (EI, 70 eV) m/z: 214 ([Mþ ꢀ 44], 100%); 213 (37),
185 (61); 108 (44), 107 (32); 105 (39); 90 (27); 77 (39).

3574
V.A. Shcherbinin, V.V. Konshin / Tetrahedron 75 (2019) 3570e3578
Table 3
Reaction of 1,3-dioxolan-4-ones 3a-g with 1-alkynes 6a-e.a
Entry
1
Nucleophile
Product
Yield (%)
Entry
7
Nucleophile
Product
Yieldb (%)
75 (60:40)c
33f (83:17)
2
3
64 (57:43)
54 (75:25)
8
9
73d (80:20)
45e (80:20)
4
5
58 (81:19)
53 (75:25)
10
11
67 (75:25)
50 (75:25)
6
45f (82:18)
a
The reaction was carried out using dioxolan-4-one (0.50 mmol) in toluene (5 mL), 1-alkyne (0.60 mmol), DIPEA (0.50 mmol), TMSOTf (0.50 mmol), and ZnBr2 (0.05 mmol)
under an argon atmosphere at ꢀ10 ꢁC.
b
Yield of pure products (the ratio of diastereomers is given in parentheses).
Ratio of diastereomers according to the NMR analysis.
c
d
The reaction was carried out for 3 h.
e
The reaction was carried out for 4.5 h at 0 ꢁC.
f
The reaction was carried out for 4 h at 0 ꢁC and, then, for 24 h at 5 ꢁC.
4.2.5. 2-Phenyl-5-(4-(trifluoromethyl)phenyl)-1,3-dioxolan-4-one
(3f)
([Mþ ꢀ 44], 100%); 246 (24), 235 (50); 195 (33); 167 (30), 105 (52);
90 (50); 77 (50).
Colourless crystals, mp 110e111ꢁС (i-octane:CHCl3). 1H NMR
(400 MHz, CDCl3): 7.65e7.72 (m, 6H, HAr), 7.56e7.59 (m, 3H, HAr),
7.47e7.52 (m, 4H, HAr), 6.71 (s, 0.36H, CH, minor), 6.61 (d, J ¼ 0.8 Hz,
1H, CH, major), 5.54 (s, 0.36H, CH, minor), 5.48 (s, 1H, CH, major)
4.2.6. 5-(4-Bromophenyl)-2-phenyl-1,3-dioxolan-4-one (3g)
Colourless crystals, mp 87e88ꢁС (i-octane). 1H NMR (400 MHz,
CDCl3): 7.54e7.60 (m, 5.6H, HAr), 7.46e7.52 (m, 4H, HAr), 7.44 (d,
J ¼ 8.4 Hz, 0.75H, HAr, minor), 7.39 (d, J ¼ 8.4 Hz, 2H, HAr, major),
6.68 (s, 0.35H, CH, minor), 6.57 (d, J ¼ 0.4 Hz, 1H, CH, major), 5.46 (s,
0.34H, CH, minor), 5.39 (s, 1H, CH, major) ppm. 13C NMR (101 MHz,
ppm. 13C NMR (101 MHz, CDCl3)
d 170.6, 137.3, 137.1, 134.9, 134.2,
131.5 (q, J2 ¼ 32.5 Hz), 131.1, 130.8, 129.0, 127.0, 126.8, 126.42,
C-F
126.39, 126.1 (q, J3 ¼ 3.6 Hz, minor), 125.9 (q, J3 ¼ 3.6 Hz, ma-
C-F
C-F
jor), 124.0 (q, J1 ¼ 270.8 Hz), 104.1, 103.7, 76.3, 74.7 ppm. IR: 2914,
C-F
CDCl3)
d 170.9, 170.8, 134.9,134.2, 132.4, 132.3 (2C), 132.1 (3C), 131.0,
1794, 1402, 1333, 1117, 1069, 831 cmꢀ1. MS (EI, 70 eV) m/z: 264
130.7, 129.0 (4C), 128.5 (2C), 127.8 (2C), 126.8 (2C), 126.4 (2C), 123.6,

V.A. Shcherbinin, V.V. Konshin / Tetrahedron 75 (2019) 3570e3578
3575
123.5, 103.9, 103.5, 76.6, 74.8 ppm. IR: 2922, 1792, 1398, 1227, 1207,
1070, 920 cmꢀ1. MS (EI, 70 eV) m/z: 276 (45); 274 (47), 195 (100),
167 (46); 166 (33), 105 (53); 90 (40); 89 (88); 77 (51).
(m, 1H, CH2), 2.46e2.51 (m, 1H, CH2) ppm. 13C NMR (151 MHz,
CDCl3) 174.4, 139.8, 135.5, 134.1, 129.2, 128.90 (2C), 128.86 (2C),
128.5, 127.9 (2C), 127.2 (2C), 117.7, 79.5, 77.3, 42.3 ppm. IR: 3028,
2903, 1722, 1703, 1454, 1238, 1188, 1113, 727, 698 cmꢀ1. MS (EI,
70 eV) m/z: 269 (8%); 163 (21); 135 (13); 132 (11); 131 (100); 107
(13); 91 (29); 79 (12); 77 (13).
d
4.3. A typical procedure for synthesis of 2-(4-nitrophenyl)-5-
phenyl-1,3-dioxolan-4-one (3b)
The products 5b-j were prepared by the similar procedure.
To a stirring solution of 1.14 g (7.5 mmol) D,L-mandelic acid and
0.756 g (5 mmol) of p-nitrobenzaldehyde in 20 mL ACN at 0ꢁС in
the argon atmosphere, was added 0,95 mL (7,5 mmol) BF3*OEt2. The
reaction mixture was stirred for 3 h at 0ꢁС, poured to saturated
sodium carbonate solution and extracted DCM. The organic phase
was washed consistently with saturated sodium carbonate solution
and distilled water, dried with anhydrous Na2SO4 and evaporated.
The residue was purified by column chromatography using MeOt-
Bu:Hex ¼ 1:4 /1:2 as the eluent and recrystallized from mixture
of i-octane: chloroform, to give compound 3b (cis diastereomer)
(700 mg, 49%) and 3b′ (trans diastereomer) (326 mg, 23%) as
colorless crystals.
4.4.1. 2-(4-fluorophenyl)-2-((1-phenylbut-3-en-1-yl)oxy)acetic
acid (5b)
Colourless crystals, mp 79e81ꢁС. 1H NMR (400 MHz, CDCl3):
7.85 (bs, 1H, OH), 7.29e7.39 (m, 8H, HAr), 7.22e7.26 (m, 3.7H, HAr),
7.09 (t, J ¼ 8.8 Hz, 1.4H, CH, minor), 7.00 (t, J ¼ 8.8 Hz, 2H, CH, ma-
jor), 5.83e5.93 (m, 1H, ¼CH, major), 5.63e5.73 (m, 0.64H, ¼CH,
minor), 5.00e5.15 (m, 3.3H, ¼CH2, major þ minor), 4.77 (s, 1H, CH,
major), 4.72 (s, 0.63H, CH, minor), 4.54 (t, J ¼ 6.8 Hz, 1H, CH, major),
4.22 (t, J ¼ 6.8 Hz, 0.65H, CH, minor), 2.65e2.76 (m, 1.7H, CH2,
major þ minor), 2.43e2.55 (m, 1.7H, CH2, major þ minor) ppm. 13
C
NMR (101 MHz, CDCl3)
d
175.7, 174.0, 163.3 (d, J1 ¼ 246.8 Hz,
C-F
2-(4-nitrophenyl)-5-phenyl-1,3-dioxolan-4-one (3b, cis-diaste-
reomer): colourless crystals, mp 103.5e104.5ꢁС (i-octane:CHCl3).
1H NMR (400 MHz, CDCl3): 8.33 (dt, J ¼ 8.8 Hz, J ¼ 2 Hz, 2H, HAr),
7.78 (dt, J ¼ 8.8 Hz, J ¼ 2 Hz, 2H, HAr), 7.42e7.46 (m, 5H, HAr), 6.67 (s,
1H, CH), 5.48 (d, J ¼ 0.8 Hz, 1H, CH). ppm. 13C NMR (101 MHz, CDCl3)
minor), 163.0 (d, J1 ¼ 246.1 Hz, major), 140.3, 139.7, 134.4, 134.0,
C-F
132.1 (d, J3 ¼ 3.1 Hz, 2C, major), 131.4 (d, J3 ¼ 2.9 Hz, 2C, minor),
C-F
C-F
131.36, 129.8, 129.7, 129.0, 128.95 (2C), 128.7 (2C), 128.6, 128.4,
127.2, 127.0, 117.9, 117.8, 116.0 (d, J2 ¼ 21.6 Hz, 2C, minor), 115.6 (d,
C-F
J2 ¼ 21.6 Hz, 2C, major), 81.8, 79.7, 77.3, 76.7, 42.6, 42.2 ppm. IR:
C-F
d
170.6, 149.4, 141.0, 132.9, 129.7, 129.1 (2C), 127.8 (2C), 127.1 (2C),
3078, 3030, 2976, 2903, 1724, 1510, 1223, 1113, 1094, 760, 700 cmꢀ1
.
124.2 (2C), 101.4, 77.2. ppm. IR: 1813, 1794, 1528, 1350, 1271, 1223,
1182, 854, 735, 696 cmꢀ1. MS (EI, 70 eV) m/z: 241 ([Mþ ꢀ 44], 100%);
212 (26); 166 (22); 165 (24); 135 (57); 105 (58); 90 (83); 89 (65); 77
(68).
Major diastereomer: ret. time 8.565 MS (EI, 70 eV) m/z: 287 (6%);
181 (30); 153 (6); 132 (11); 131 (100); 129 (8), 125 (15); 109 (13); 91
(15). Minor diastereomer: ret. time 8.625 MS (EI, 70 eV) m/z: 287
(9%); 181 (52); 153 (10); 132 (11); 131 (100); 125 (21); 109 (20); 91
(17). HRMS: [M ꢀ H]-, found 299.1089, C18H16FO3 requires 299.1089.
2-(4-nitrophenyl)-5-phenyl-1,3-dioxolan-4-one (3b′, trans-dia-
stereomer): colourless crystals, mp 125,8e126,5ꢁС (i-octa-
ne:CHCl3). 1H NMR (400 MHz, CDCl3): 8.33 (d, J ¼ 8.8 Hz, 2H, HAr),
7.7 (d, J ¼ 8.8 Hz, 2H, HAr), 7.53e7.56 (m, 2H, HAr), 7.43e7.49 (m, 3H,
4.4.2. 2-((1-Phenylbut-3-en-1-yl)oxy)-2-(4-(trifluoromethyl)-
phenyl)acetic acid (5c)
H
Ar), 6.76 (s, 1H, CH), 5.51 (s, 1H, CH) ppm. 13C NMR (101 MHz,
Colourless crystals, mp 95e96ꢁС. 1H NMR (400 MHz, CDCl3):
8.87 (bs, 1.9H, OH), 7.67 (d, J ¼ 8.4 Hz, 2.6H, HAr, major), 7.58
CDCl3) d 170.4, 149.3, 141.7, 132.6, 129.6, 129.3 (2C), 127.5 (2C), 126.3
(2C), 124.2 (2C), 102.0, 75.4 ppm. IR: 1796, 1521, 1224, 1198, 1180,
1072, 1005, 743, 735 cmꢀ1. MS (EI, 70 eV) m/z: 241 ([Mþ ꢀ 44],
100%); 212 (27); 135 (63); 105 (67); 90 (91); 89 (72); 77 (73).
(d J ¼ 8.4 Hz, 2H, HAr
,
minor), 7.50e7.54 (m, 4.7H, HAr,
major þ minor), 7.30e7.40 (m, 6.7H, HAr, major þ minor), 7.21e7.26
(m, 5H, HAr, major þ minor), 5.83e5.94 (m, 1H, ¼CH, minor),
5.64e5.75 (m, 1.3H, ¼CH, major), 5.05e5.16 (m, 3.4H, ¼CH2,
major þ minor), 5.02 (s, 1.3H, ¼CH2, major), 4.84 (s, 1H, CH, minor),
4.80 (s, 1.3H, CH, major), 4.57 (dd, J ¼ 7.6 Hz, J ¼ 5.6 Hz, 1H, CH,
minor), 4.23 (dd, J ¼ 7.2 Hz, J ¼ 6.4 Hz,1.3H, CH, major), 2.68e2.77
4.4. A typical procedure for synthesis of acids 5a-j
To a solution of dioxolanone 3a (144 mg, 0.6 mmol) and allyl-
trimethylsilane 4a (144
mL, 0.9 mmol) in dry CH2Cl2 (5.5 mL) under
(m, 2.4H, CH2, major
þ
minor), 2.45e2.57 (m, 2.4H, CH2,
an argon atmosphere, FeCl3 (9.7 mg, 0.06 mmol) was added at room
temperature. The reaction mixture was stirred for 30 min, poured
into water, and extracted with EtOAc. The organic phase was dried
with anhydrous Na2SO4 and evaporated. The residue was purified
by column chromatography using EtOAc:Hex (1 : 9) as eluent to
give compound 5a (142 mg, 84%) as a colorless solid (dr ¼ 1 : 1.5).
2-phenyl-2-((1-phenylbut-3-en-1-yl)oxy)acetic acid (5a) (minor
diastereomer): colourless crystals, mp 119e120ꢁС. 1H NMR
(600 MHz, CDCl3): 10.27 (bs, 1H, OH), 7.40e7.41 (m, 2H, HAr),
7.31e7.36 (m, 6H, HAr), 7.27e7.28 (m, 2H, HAr), 5.88e5.95 (m, 1H,
CH2]C-H), 5.10e5.15 (m, 2H, ¼CH2), 4.82 (s, 1H, CH), 4.58 (t,
J ¼ 6.6 Hz, 1H, CH), 2.72e2.77 (m, 1H, CH2), 2.52e2.56 (m, 1H, CH2)
major þ minor) ppm. 13C NMR (101 MHz, CDCl3)
d 175.5,173.7,140.0
(2C), 139.6, 139.4, 134.3, 133.8, 131.4 (q, J2 ¼ 32.3 Hz, major), 130.9
C-F
(q, J2 ¼ 32.3 Hz, minor), 129.0 (2C), 128.8 (3C), 128.5, 128.2 (2C),
C-F
127.4 (2C), 127.2 (2C), 127.0 (2C), 125.9 (d, J3 ¼ 3.6 Hz, 2C, major),
C-F
125.6 (d, J3 ¼ 3.6 Hz, 2C, minor), 124.1 (q, J1 ¼ 270.8 Hz, minor),
C-F
C-F
124.0 (q, J1 ¼ 270.9 Hz, major), 118.1, 118.0, 82.0, 80.3, 77.4, 77.2,
C-F
42.6, 42.2 ppm. IR: 3069, 2909, 1728, 1420, 1325, 1163, 1128, 914,
702 cmꢀ1. Minor diastereomer: ret. time 8.350 MS (EI, 70 eV) m/z:
337 (20%); 231 (30); 203 (18); 175 (17); 159 (13); 132 (11); 131
(100); 129 (10); 127 (11); 91 (21). Major diastereomer: ret. time
8.385 MS (EI, 70 eV) m/z: 337 (40%); 231 (63); 203 (38); 175 (34);
159 (26); 131 (100); 129 (13); 127 (19); 91 (26). HRMS: [M ꢀ H]-,
found 349.1056, C19H16O3F3O3 requires 349.1057.
ppm. 13C NMR (151 MHz, CDCl3)
d 176.6, 140.4, 136.2, 134.5, 128.8,
128.7 (4C), 128.3, 127.2 (2C), 127.1 (2C), 117.8, 81.6, 77.8, 42.6 ppm.
IR: 3028, 2903, 1722, 1703, 1454, 1238, 1188, 1113, 727, 698 cmꢀ1. MS
(EI, 70 eV) m/z: 269 (8%); 163 (21); 135 (13); 132 (11); 131 (100); 107
(13); 91 (29); 79 (12); 77 (13).
2-phenyl-2-((1-phenylbut-3-en-1-yl)oxy)acetic acid (5a) (major
diastereomer): colourless crystals. mp 89e90ꢁС. 1H NMR
(600 MHz, CDCl3): 9.94 (bs, 1H, OH), 7.34e7.42 (m, 8H, HAr),
7.27e7.28 (m, 2H, HAr), 5.66e5.73 (m, 1H, CH2]C-H), 5.01e5.04 (m,
2H, ¼CH2), 4.74 (s, 1H, CH), 4.26 (t, J ¼ 10.2 Hz, 1H, CH), 2.69e2.74
4.4.3. 2-(4-bromophenyl)-2-((1-phenylbut-3-en-1-yl)oxy)acetic
acid (5d)
Pale oil. 1H NMR (400 MHz, CDCl3): 8.61 (bs,1.3H, OH), 7.52e7.54
(m, 2H, HAr), 7.43e7.46 (m, 1.7H, HAr), 7.29e7.39 (m, 5.6H, HAr),
7.21e7.26 (m, 7.8H,
H
Ar), 5.82e5.90 (m, 0.8H, ¼CH, minor),
5.62e5.73 (m, 1H, ¼CH, major), 5.00e5.14 (m, 3.8H, ¼CH2,
major þ minor), 4.73 (s, 0.8H, CH, minor), 4.69 (s, 1H, CH, major),
4.53 (dd, J ¼ 7.6 Hz, J ¼ 5.6 Hz, 0.9H, CH, minor), 4.22 (dd, J ¼ 7.6 Hz,

3576
V.A. Shcherbinin, V.V. Konshin / Tetrahedron 75 (2019) 3570e3578
J ¼ 6.0 Hz, 1H, CH, major), 2.65e2.75 (m, 1.9H, CH2, major þ minor),
2.43e2.54 (m, 1.9H, CH2, major þ minor) ppm. 13C NMR (101 MHz,
1188, 1136, 1096, 706 cmꢀ1. Minor diastereomer: ret. time 9.790 MS
(EI, 70 eV) m/z: 297 (24%); 191 (65); 163 (80); 135 (44); 131 (28);
121 (32); 91 (42); 73 (100). Major diastereomer: ret. time 9.880 MS
(EI, 70 eV) m/z: 269 (21%); 191 (54); 163 (100); 135 (47); 131 (26);
121 (31); 107 (29); 105 (22); 91 (48); 73 (88).
CDCl3)
d 175.6, 173.7, 140.1, 139.5, 135.2, 134.6, 134.3, 133.9, 132.2
(2C), 131.8 (2C), 129.5 (2C), 129.0 (2C), 128.8 (2C), 128.75 (2C),
128.69, 128.4, 127.2 (2C), 127.0 (2C), 123.5, 123.0, 118.0, 117.9, 81.8,
79.9, 77.4, 76.7, 42.6, 42.2 ppm. IR: 3067, 2913, 1728, 1713, 1487,
1186, 1092, 1013, 918, 760 cmꢀ1. Minor diastereomer: ret. time
10.095 MS (EI, 70 eV) m/z: 349 (3%); 347 (3); 243 (13); 241 (13); 187
(4); 185 (5); 162 (5); 132 (11); 131 (100); 129 (8); 91 (15); 77 (7).
Major diastereomer: ret. time 10.165 MS (EI, 70 eV) m/z: 349 (4%);
347 (4); 243 (19); 241 (20); 185 (7); 162 (7); 132 (11); 131 (100); 129
(9); 91 (16); 77 (9).
4.4.7. 2-(3-methoxy-2,2-dimethyl-3-oxo-1-phenylpropoxy)-2-(4-
(trifluoromethyl)phenyl)acetic acid (5h)
Pale oil. 1H NMR (400 MHz, CDCl3): 7.74 (bs, 1H, OH), 7.58e7.64
(m, 3H, HAr), 7.49e7.51 (m, 0.8H, HAr), 7.32e7.39 (m, 5.2H, HAr),
7.23e7.23 (m, 2.3H, HAr), 7.14e7.16 (m, 0.8H, HAr), 4.96 (s, 0.37H, CH,
minor), 4.79 (s, 0.38H, CH, minor), 4.73 (s, 1H, CH, major), 4.53 (s,
1H, CH, major), 3.79 (s, 1.1H, OCH3, minor), 3.53 (s, 3H, OCH3, ma-
jor), 1.25 (s, 1H, CH3, minor), 1.21 (s, 3H, CH3, major), 1.06 (s, 1.1H,
CH3, minor), 0.99 (s, 3H, CH3, major) ppm. 13C NMR (101 MHz,
4.4.4. 2-((2,2-Dimethylhex-5-en-3-yl)oxy)-2-phenylacetic acid (5e)
Colourless crystals, mp 53e54ꢁС. 1H NMR (400 MHz, CDCl3):
9.72 (bs, 1H, OH), 7.43e7.45 (m, 2H, HAr), 7.33e7.38 (m, 4.6H, HAr),
5.87e5.95 (m, 0.3H, ¼CH, minor), 5.53e5.63 (m, 1H, ¼CH, major),
5.08e5.18 (m, 0.5H, ¼CH2, minor), 5.08 (s, 1H, CH, major), 5.04 (s,
0.33H, CH, minor), 4.82e4.93 (m, 2H, ¼CH2, major), 3.28 (dd,
J ¼ 6.4 Hz, J ¼ 4 Hz, 1H, CH, major), 3.20 (dd, J ¼ 7.6 Hz, J ¼ 3.6 Hz,
0.32H, CH, minor), 2.47e2.52 (m, 0.32H, CH2, minor), 2.32e2.40 (m,
1.32H, CH2, major þ minor), 2.14e2.21 (m, 1H, CH2, major), 1.00 (s,
9H, t-Bu, major), 0.83 (s, 3H, t-Bu, minor) ppm. 13C NMR (101 MHz,
CDCl3) d 178.8, 176.6, 173.4, 173.1, 140.3, 139.4, 135.4, 135.0, 131.4 (q,
J2 ¼ 32.5 Hz, major), 130.6 (q, J2 ¼ 32.3 Hz, minor), 129.0, 128.9,
C-F
C-F
128.8,128.7 (2C),128.52 (4C),128.48 (2C), 128.4,127.1 (2C), 125.7 (q,
J3 ¼ 3.6 Hz, 2C, major),125.6 (q, J3 ¼ 3.6 Hz, 2C, minor),124.1 (q,
C-F
J1C-F ¼ 270.7 Hz, minor),124.0 (q, J3 ¼ 270.8 Hz, minor), 85.4, 84.7,
C-F
C-F
77.5, 77.3, 52.8, 52.0, 47.9, 47.8, 22.85, 22.78, 19.3,18.6 ppm. 19F NMR
(376 MHz, CDCl3):
d
ꢀ62.59, 62.61 ppm. IR: 3030, 2986, 2951, 1730,
1713, 1454, 1325, 1126, 1018, 756, 706 cmꢀ1. Minor þ major dia-
stereomer: ret. time 9.300 MS (EI, 70 eV) m/z: 337 (48%); 231 (100);
203 (48); 191 (54); 175 (39); 159 (34); 131 (36); 73 (63).
CDCl3)
d 175.7, 174.2, 137.0, 136.8, 136.6, 136.1, 129.0, 128.8, 128.7
(2C), 128.6 (2C), 128.1 (2C), 127.5 (2C), 117.6, 116.4, 87.7, 87.4, 81.0,
80.5, 36.3, 35.8, 35.7, 35.6, 26.65 (3C), 26.58 (3C) ppm. IR: 2957,
1726, 1705, 1261, 1219, 1186, 1099, 1074, 719 cmꢀ1. MS (EI, 70 eV) m/
z: 163 (100%); 135 (34); 111 (32); 107 (50); 91 (30); 79 (23); 69 (32).
4.4.8. 2-(4-fluorophenyl)-2-(3-methoxy-2,2-dimethyl-3-oxo-1-
phenylpropoxy)acetic acid (5i)
Colourless oil. 1H NMR (400 MHz, CDCl3): 8.42 (bs, 1.1H, OH),
7.29e7.39 (m, 4.8H, HAr), 7.15e7.24 (m, 4.9H, HAr), 6.98e7.07 (m,
2.9H, HAr), 4.92 (s, 0.36H, CH, minor), 4.71 (s, 0.36H, CH, minor),
4.65 (s, 1H, CH, major), 4.50 (s, 1H, CH, major), 3.79 (s, 1.1H, OCH3,
minor), 3.55 (s, 3H, OCH3, major), 1.26 (s, 1.3H, CH3, minor), 1.20 (s,
3H, CH3, major), 1.05 (s, 1.1H, CH3, minor), 0.99 (s, 3H, CH3, major)
4.4.5. 2-((3-methyl-1-phenylbut-3-en-1-yl)oxy)-2-phenylacetic
acid (5f)
Minor diastereomer: colourless crystals, mp 80.1e80.6ꢁС. 1H
NMR (400 MHz, CDCl3): 7.28e7.35 (m, 8H, HAr), 7.24e7.26 (m, 1H,
H
Ar), 4.92 (s,1H, ¼CH2), 4.88 (s,1H, ¼CH2), 4.80 (s,1H, CH), 4.58 (dd,
J ¼ 8.8 Hz, J ¼ 4.8 Hz, 1H, CH), 2.72 (dd, J ¼ 14.0 Hz, J ¼ 8.8 Hz, 1H,
ppm. 13C NMR (101 MHz, CDCl3)
d 178.8, 176.5, 174.0, 173.4, 163.3 (d,
CH2), 2.39 (dd, J ¼ 14.0 Hz, J ¼ 4.8 Hz, 1H, CH2), 1.83 (s, 3H, CH3)
J1 ¼ 247 Hz, major), 162.9 (d, J1 ¼ 245.8 Hz, minor),135.4,135.2,
C-F
C-F
ppm. 13C NMR (101 MHz, CDCl3)
d
174.5, 142.5, 140.4, 136.1, 128.75,
132.4 (d, J4 ¼ 3.1 Hz, minor), 131.0 (d, J4 ¼ 2.9 Hz, major), 130.1
C-F
C-F
128.68 (2C), 128.64 (2C), 128.3, 127.0 (2C), 126.94 (2C), 114.3, 80.8,
78.2, 46.9, 22.9 ppm. IR: 3075, 2899, 1717, 1456, 1242, 1119, 885,
723 cmꢀ1. MS (EI, 70 eV) m/z: 269 (20%); 163 (45); 145 (100); 135
(26); 129 (14); 117 (12); 107 (12); 91 (19); 79 (13); 77 (12).
(d, J3 ¼ 8.4 Hz, 2C, major), 128.87 (2C), 128.85 (2C), 128.82 (2C),
C-F
128.7 (2C), 128.6, 128.5 (2C), 128.3, 115.8 (d, J2 ¼ 21.8 Hz, 2C,
C-F
major), 115.6 (d, J2 ¼ 21.5 Hz, 2C, minor), 85.2, 84.0, 77.4, 77.2,
C-F
52.8, 52.0, 47.85, 47.80, 23.2, 22.8, 19.3, 18.7 ppm. IR: 3028, 2986,
1728, 1713, 1605, 1508, 1225, 1090, 835, 756 cmꢀ1. Minor diaste-
reomer: ret. time 9.550 MS (EI, 70 eV) m/z: 315 (23%); 287 (10); 192
(16); 191 (97); 181 (87); 135 (25); 131 (38); 125 (30); 121 (44); 109
(38); 73 (100). Major diastereomer: ret. time 9.595 MS (EI, 70 eV) m/
z: 315 (17%); 287 (12); 191 (72); 182 (13); 181 (100); 153 (19); 135
(19); 131 (28); 125 (30); 121 (33); 109 (39); 73 (78). HRMS:
[M ꢀ H]-, found 359.1297, C20H20FO5 requires 359.1300.
Major diastereomer: colourless crystals, mp 82e83ꢁС. 1H NMR
(400 MHz, CDCl3): 7.30e7.39 (m, 8H, HAr), 7.23e7.25 (m, 2H, HAr),
4.77 (s, 1H, ¼CH2), 4.71 (s, 1H, CH), 4.67 (s, 1H, ¼CH2), 4.34 (dd,
J ¼ 8.4 Hz, J ¼ 5.2 Hz, 1H, CH), 2.67 (dd, J ¼ 14.0 Hz, J ¼ 8.4 Hz, 1H,
CH2), 2.36 (dd, J ¼ 14.0 Hz, J ¼ 5.2 Hz, 1H, CH2), 1.58 (s, 3H, CH3)
ppm. 13C NMR (101 MHz, CDCl3)
d 173.3, 141.6, 140.0, 135.3, 129.3,
128.9 (4C), 128.6, 128.0 (2C), 127.2 (2C), 113.8, 78.2, 77.3, 46.4,
22.7 ppm. IR: 3088, 2966, 1763, 1452, 1306, 1092, 1065, 868,
779 cmꢀ1. MS (EI, 70 eV) m/z: 269 (35%); 163 (89); 145 (100); 135
(50); 129 (17); 117 (13); 107 (21); 91 (30); 79 (22); 77 (18). HRMS:
[M ꢀ H]-, found 295.1337, C19H19O3 requires 295.1340.
4.4.9. 2-(3-oxo-1,3-diphenylpropoxy)-2-phenylacetic acid (5j)
Minor diastereomer: colourless crystals, mp 104e106ꢁС. 1H
NMR (400 MHz, CDCl3): 12.36 (bs, 1H, OH), 8.01e8.03 (m, 2H, HAr),
7.62e7.66 (m, 1H, HAr), 7.48e7.51 (m, 2H, HAr), 7.38e7.42 (m, 3H,
4.4.6. 2-(3-methoxy-2,2-dimethyl-3-oxo-1-phenylpropoxy)-2-
phenylacetic acid (5g)
H
Ar), 7.31e7.35 (m, 8H, HAr), 5.16 (dd, J ¼ 10.4 Hz, J ¼ 1.6 Hz, 1H, CH),
4.85 (s, 1H, CH), 3.72 (dd, J ¼ 18.0 Hz, J ¼ 10.4 Hz, 1H, CH2), 3.39 (dd,
Colourless crystals, mp 83e85ꢁС. 1H NMR (400 MHz, CDCl3):
7.64 (bs, 1.3H, OH), 7.30e7.37 (m, 11H, HAr), 7.17e7.24 (m, 5H, HAr),
4.94 (s, 0.56H, CH, minor), 4.75 (s, 0.56H, CH, minor), 4.67 (s,1H, CH,
major), 4.52 (s, 1H, CH, major), 3.79 (s, 1.6H, OCH3, minor), 3.54 (s,
3H, OCH3, major), 1.27 (s, 1.7H, CH3, minor), 1.20 (s, 3H, CH3, major),
1.06 (s, 1.7H, CH3, minor), 1.00 (s, 3H, CH3, major) ppm. 13C NMR
J ¼ 18.0 Hz, J ¼ 1.6 Hz, 1H, CH2) ppm. 13C NMR (101 MHz, CDCl3)
d
199.8, 172.6, 138.7, 136.5, 135.8, 134.5, 129.3 (2C), 129.2, 129.0 (2C),
128.73, 128.68 (2C), 128.64 (2C), 127.1 (2C), 127.0 (2C), 78.5, 77.0,
46.6 ppm. IR: 3510, 3387, 1705, 1670, 1327, 1219, 1107, 702,
691 cmꢀ1. MS (EI, 70 eV) m/z: 208 (Mþ, 83%); 207 (100); 131 (38);
105 (44); 103 (52); 77 (86); 51 (42).
(101 MHz, CDCl3)
d
178.8, 176.5, 173.9, 173.0, 136.6, 135.5, 135.3,
Major diastereomer: colourless crystals, mp 104e106ꢁС. 1H
NMR (400 MHz, CDCl3): 8.14 (bs, 1H, OH), 7.89e7.91 (m, 2H, HAr),
7.52e7.56 (m, 1H, HAr), 7.41e7.44 (m, 2H, HAr), 7.27e7.37 (m, 10H,
135.1, 129.4 (2C), 128.9 (2C), 128.8 (4C), 128.7 (2C), 128.6 (2C), 128.4
(2C),128.3 (4C), 126.8 (2C), 85.1, 84.0, 78.1, 77.9, 52.8, 52.0, 47.8 (2C),
23.3, 22.8, 19.4, 18.7 ppm. IR: 3462, 3453, 2990, 1740, 1726, 1263,
HAr), 4.93 (dd, J ¼ 7.6 Hz, J ¼ 5.6 Hz, 1H, CH), 4.74 (s, 1H, CH), 3.70

V.A. Shcherbinin, V.V. Konshin / Tetrahedron 75 (2019) 3570e3578
3577
(dd, J ¼ 16.4 Hz, J ¼ 7.6 Hz, 1H, CH2), 3.28 (dd, J ¼ 16.4 Hz, J ¼ 5.6 Hz,
1H, CH2) ppm. 13C NMR (101 MHz, CDCl3)
197.2, 174.2, 139.5, 137.0,
135.0, 133.4, 129.3, 129.0 (2C), 128.8 (2C), 128.74, 128.70 (2C), 128.3
(9); 105 (7). HRMS: [M ꢀ H]-, found 409.1034, C24H16F3O3 requires
409.1057.
d
Mixture of diastereomers: pale oil. 1H NMR (400 MHz, CDCl3):
8.12 (bs, 1H, OH), 7.69 (m, 1,3H, HAr), 7.63e7.65 (m, 6.1H, HAr),
7.29e7.46 (m, 11,6H, HAr), 5.70 (s, 1H, CH, major), 5.50 (s, 0.34H, CH,
(2C), 127.9 (2C), 127.3 (2C), 77.5, 75.9, 46.9 ppm. IR(смесь): 3510,
3387,1705,1670,1327,1219,1107, 702, 691 cmꢀ1. MS (EI, 70 eV) m/z:
208 (Mþ, 83%); 207 (100); 131 (38); 105 (44); 103 (52); 77 (86); 51
(42).
minor), 5.46 (s, 1H, CH, major), 5.42 (s, 0.34H, CH, minor) ppm. 13
C
NMR (101 MHz, CDCl3) d 175.4, 174.0, 139,7, 139.3, 137.4, 137.2, 131.9
(4C), 131.1 (q, J2 ¼ 32.3 Hz, 2C, major þ minor), 129.25, 129.20,
C-F
4.5. A typical procedure for synthesis of acids 7a-k
129.1 (2C), 128.9, 128.8 (3C), 128.5 (4C), 128.2, 127.94 (3C), 127.90,
127.86 (3C), 126.0 (q, J3 ¼ 3.5 Hz, 2C, minor), 125.7 (q, J3
C-F
C-
To a solution of phenylacetylene (66
mL, 0.6 mmol) in dry
¼ 3.5 Hz, 2C, major), 124.0 (q, J1 ¼ 270.8 Hz, 2C, major þ minor),
F
C-F
toluene (4 mL) under an argon atmosphere, DIPEA (87
mL,
122.0, 121.8, 89.8, 89.6, 85.3, 84.9, 77.4, 77.0, 71.9, 71.3 ppm. IR:
3065, 2926, 1728, 1713, 1491, 1325, 1167, 1069, 758 cmꢀ1. Ret. time
13.060 MS (EI, 70 eV) m/z: 208 (14%); 207 (79); 192 (18); 191 (100);
190 (7); 189 (17); 165 (5); 129 (8); 105 (7).
0.5 mmol) and ZnBr2(11.3 mg, 0.5 mmol) were added at room
temperature. The reaction mixture was stirred for 30 min at room
temperature and cooled to ꢀ10ꢁС. A cooled to ꢀ10 ꢁC solution of
dioxolanone 3a (120.1 mg, 0.5 mmol) and TMSOTf (90 mL, 0.5 mmol)
in toluene (1 mL) was added. The resulting mixture was stirred for
2 h, poured into water acidified with 2 N HCl (1 mL), and extracted
with EtOAc. The organic phase was dried with anhydrous Na2SO4
and evaporated. The residue was purified by column chromatog-
raphy using gradient elution with EtOAc:Hex (1:10 / 1:6) to give
compound 7a (128.4 mg, 75%) as a pale oil (dr ¼ 1:1.5).
4.5.3. 2-(4-bromophenyl)-2-((1,3-diphenylprop-2-yn-1-yl)oxy)-
acetic acid (7d)
Coloureless oil. 1H NMR (400 MHz, CDCl3): 8.83 (bs, 0.9H, OH),
7.62e7.64 (m, 2H, HAr), 7.56e7.58 (m, 1H, HAr), 7.48e7.51 (m, 2.3H,
H
Ar), 7.43e7.46 (m, 2.9H, HAr), 7.31e7.41 (m, 9.8H, HAr), 5.66 (s, 1H,
CH, major), 5.41 (s, 0.23H, CH, minor), 5.38 (s, 0.24H, CH, minor),
5.34 (s, 1H, CH, major) ppm. 13C NMR (101 MHz, CDCl3)
175.8,
2-((1,3-diphenylprop-2-yn-1-yl)oxy)-2-phenylacetic acid (7a).
Pale oil. 1H NMR (600 MHz, CDCl3): 9.57 (bs, 2H, OH), 7.66e7.67 (m,
3H, HAr), 7.56e7.60 (m, 4H, HAr), 7.47e7.52 (m, 9H, HAr), 7.31e7.43
(m, 23H, HAr), 5.66 (s, 1.5H, CH, major), 5.49 (s, 1H, CH, minor), 5.40
(s, 1.5H, CH, major), 5.38 (s, 1H, CH, minor) ppm. 13C NMR (150 MHz,
d
174.3, 137.5, 137.3, 134.8, 134.3, 132.3 (2C), 132.0 (6C), 129.5, 129.2
(2C), 129.14 (2C), 129.05 (2C), 128.9 (2C), 128.8 (2C), 128.52 (3C),
128.49 (2C), 127.93 (2C), 127.88 (2C), 123.6, 123.2, 122.1, 121.9, 89.6,
89.3, 85.5, 85.0, 77.4, 76.9, 71.7, 70.9 ppm. IR: 3030, 2924, 1724,
1489, 1215, 1072, 1013, 756 cmꢀ1. Ret. time 21.125 MS (EI, 70 eV) m/
z: 208 (7%); 207 (38); 192 (19); 191 (100); 190 (6); 189 (14); 165 (4);
105 (4).
CDCl3)
d 176.4, 174.8, 137.7, 137.6, 135.7, 135.2, 132.0 (4C), 130.3,
129.4, 129.1, 129.04, 129.02, 129.0, 128.9 (2C), 128.81 (2C), 128.77
(2C), 128.7 (2C), 128.5 (2C), 128.4 (2C), 128.0 (4C), 127.9 (2C), 127.6
(2C), 122.2, 122.1, 89.3,89.0, 85.8, 85.3, 78.1, 77.6, 71.4, 70.5 ppm. IR:
3032, 1721, 1452, 1278, 1217, 1067, 756, 696 cmꢀ1. MS (EI, 70 eV) m/
z: 207 (31%); 192 (18); 191 (100); 189 (14); 164 (8) 105 (7).
The products 7b-k were prepared by the similar procedure.
4.5.4. 2-((1-(4-bromophenyl)-3-phenylprop-2-yn-1-yl)oxy)-2-
phenylacetic acid (7e)
Pale oil. 1H NMR (400 MHz, CDCl3): 8.37 (bs, 1H, OH), 7.42e7.55
(m, 12.5H, HAr), 7.32e7.39 (m, 7.3H, HAr), 5.61 (s, 1H, CH, major),
5.46 (s, 0.33H, CH, minor), 5.39 (s, 1H, CH, major), 5.30 (s, 0.38H, CH,
4.5.1. 2-((1,3-diphenylprop-2-yn-1-yl)oxy)-2-(4-fluorophenyl)-
acetic acid (7b)
minor) ppm. 13C NMR (101 MHz, CDCl3)
d 176.1, 174.6, 136.8, 136.7,
Yellow oil. 1H NMR (400 MHz, CDCl3): 8.03 (bs, 1.1H, OH),
7.63e7.65 (m, 2H, HAr), 7.51e7.58 (m, 3.1H, HAr), 7.46e7.52 (m, 5.7H,
135.6, 135.0, 132.1 (2C), 132.0 (2C), 131.9 (2C), 131.8 (2C), 129.7, 129.6
(2C), 129.5 (2C), 129.2, 129.1 (2C), 128.9 (2C), 128.80, 128.76, 128.54
(2C), 128.51 (2C), 128.0 (2C), 127.6 (2C), 123.1, 123.0, 122.0, 121.8,
89.6, 89.4, 85.2, 84.7, 78.2, 77.7, 70.8, 69.8 ppm. IR: 3032, 2924,1719,
1487, 1069, 1030, 754, 691 cmꢀ1. MS (EI, 70 eV) m/z: 287 (30%); 285
(31); 271 (100); 270 (19); 269 (99); 189 (47); 164 (48). HRMS:
[M ꢀ H]-, found 419.0273, C23H16BrO3 requires 419.0288.
HAr), 7.32e7.43 (m, 11.4H, HAr), 7.10e7.14 (m, 1.6H, HAr), 7.03e7.07
(m, 2H, HAr), 5.65 (s, 1H, CH, major), 5.44 (s, 0.74H, CH, minor), 5.37
(s, 1H, CH, major), 5.36 (s, 0.77H, CH, minor) ppm. 13C NMR
(101 MHz, CDCl3)
d
175.9, 174.4, 163.4 (d, J1 ¼ 247 Hz, minor),
C-F
163.1 (d, J1 ¼ 246.4 Hz, major), 137.5, 137.4, 132.0 (4C), 131.6 (d,
C-F
J4 ¼ 2.9 Hz, minor), 131.1 (d, J4 ¼ 3.1 Hz, major), 129.8 (d, J3
C-F
C-F
C-
¼ 8.4 Hz, 2C, minor), 129.4 (d, J3 ¼ 8.3 Hz, 2C, major), 129.1 (2C),
4.5.5. 2-((1-(4-nitrophenyl)-3-phenylprop-2-yn-1-yl)oxy)-2-
phenylacetic acid (7f)
F
C-F
129.0 (2C), 128.8 (2C), 128.7 (2C), 128.52 (2C), 128.49 (2C), 127.95
(2C), 127.87 (2C), 122.1, 122.0, 116.1 (d, J2 ¼ 21.8 Hz, 2C, minor),
Pale oil. 1H NMR (400 MHz, CDCl3): 8.66 (bs, 1H, OH), 8.25 (d,
J ¼ 8.8 Hz, 2H, HAr, major), 8.24 (d, J ¼ 8.8 Hz, 0.47H, HAr, minor),
C-F
115.8 (d, J2 ¼ 21.5 Hz, 2C, major), 89.5, 89.2, 85.6, 85.1, 77.4, 76.9,
C-F
71.5, 70.7 ppm. IR: 3063, 2922, 1728, 1713, 1603, 1504, 1225, 1082,
835, 758 cmꢀ1. Ret. time 14.045 MS (EI, 70 eV) m/z: 208 (6%); 207
(35); 192 (19); 191 (100); 190 (6); 189 (13); 165 (4); 123 (5). HRMS:
[M ꢀ H]-, found 359.1082, C23H16FO3 requires 359.1089.
7.86 (d, J ¼ 8.8 Hz, 2H, HAr, major), 7.76 (d, J ¼ 8.4 Hz, 0.45H, HAr
,
minor), 7.56e7.58 (m, 0.4H,
7.32e7.41 (m, 7H, HAr), 5.78 (s, 1H, CH, major), 5.52 (s, 0.23H, CH,
minor), 5.50 (s, 1H, CH, major), 5.40 (s, 0.22H, CH, minor) ppm. 13
NMR (101 MHz, CDCl3) 176.3, 175.1, 148.1 (2C), 144.8, 144.7, 135.4,
HAr), 7.45e7.54 (m, 5.3H, HAr),
C
d
4.5.2. 2-((1,3-diphenylprop-2-yn-1-yl)oxy)-2-(4-(trifluoromethyl)-
phenyl)acetic acid (7c)
134.6, 132.0 (4C), 129.8, 129.42, 129.38, 129.30, 129.26 (2C), 128.9
(2C), 128.6 (6C), 128.4 (2C), 128.0 (2C), 127.5 (2C), 123.94 (2C),
123.85 (2C), 121.6, 121.5, 90.2, 90.1, 84.3, 84.0, 78.4, 78.0, 70.3,
Major diastereomer: colourless crystals, mp 104e105ꢁС. 1H
NMR (400 MHz, CDCl3): 7.63e7.65 (m, 6H, HAr), 7.40e7.44 (m, 5H,
69.0 ppm. IR: 3021, 2926, 1720, 1524, 1491, 1348, 1072, 756 cmꢀ1
.
H
Ar), 7.29e7.35 (m, 3H, HAr), 5.70 (s, 1H, CH), 5.47 (s, 1H, CH) ppm.
13C NMR (101 MHz, CDCl3)
d
175.4, 139,7, 137.4, 131.9 (2C), 131.1 (q,
4.5.6. 2-((4,4-dimethyl-1-phenylpent-1-yn-3-yl)oxy)-2-
phenylacetic acid (7g)
J2 ¼ 32.4 Hz), 129.1 (2C), 128.8 (2C), 128.5 (2C), 127.94 (2C), 127.86
C-F
(2C), 125.7 (q, J3 ¼ 3.3 Hz, 2C), 124.0 (q, J1 ¼ 270.8 Hz), 122.0,
Colourless crystals, mp 136e137ꢁС. 1H NMR (400 MHz, CDCl3):
9.02 (bs, 1H, OH), 7.53e7.56 (m, 2H, HAr), 7.46e7.50 (m, 1H, HAr),
7.30e7.41 (m, 10H, HAr), 5.44 (s, 1H, CH, major), 5.36 (s, 0.21H, CH,
minor), 4.27 (s,1H, CH, major), 3.89 (s, 0.21H, CH, minor),1.15 (s, 9H,
C-F
C-F
89.6, 85.3, 77.0, 71.9, ppm. IR: 3030, 2904, 1701, 1491, 1329, 1161,
1126, 1069, 754 cmꢀ1. Ret. time 13.055 MS (EI, 70 eV) m/z: 208
(13%); 207 (79); 192 (18); 191 (100); 190 (7); 189 (17); 165 (7); 129

3578
V.A. Shcherbinin, V.V. Konshin / Tetrahedron 75 (2019) 3570e3578
t-Bu, major), 1.09 (s, 2H, t-Bu, minor) ppm. 13C NMR (101 MHz,
CDCl3) 176.8, 174.2, 136.6, 135.3, 131.9 (4C), 129.3, 128.9, 128.8,
101.6, 101.0, 95.0, 94.6, 78.0, 77.5, 71.4, 70.5, 0.1 (6C) ppm. IR: 3034,
2959, 1728, 1707, 1252, 1117, 1040, 858, 841, 698 cmꢀ1. MS (EI,
70 eV) m/z: 221 (8%); 164 (9); 116 (12); 115 (100); 89 (7); 77 (7).
d
128.7 (2C), 128.61 (2C), 128.55 (2C), 128.49, 128.40 (2C), 127.9 (2C),
127.2 (2C), 122.7, 122.4, 88.4, 87.9, 86.1, 85.2, 78.5, 78.3, 78.1, 77.3,
36.3, 35.9, 26.1 (6C) ppm. IR: 2972, 2953, 2864, 1721, 1703, 1493,
1315, 1240, 1124, 754, 723, 690 cmꢀ1. Minor: RT 9.935MS (EI,
70 eV) m/z: 171 (68%); 164 (63); 163 (100); 156 (39); 143 (30); 135
(44); 91 (42). Major: RT 9.895 MS (EI, 70 eV) m/z: 171 (100%); 164
(70); 163 (89); 156 (55); 143 (39); 135 (35); 91 (41).
Acknowledgments
This work was financially supported by the Russian Science
Foundation, Russia (project No. 17-73-10251) and accomplished
with the use of scientific equipment of the Centre for Shared Use
“Ecoanalytical Centre” at the Kuban State University
(RFMEFI59317Х0008).
4.5.7. 2-((3-(4-nitrophenyl)-1-phenylprop-2-yn-1-yl)oxy)-2-
phenylacetic acid (7h)
Yellow oil. 1H NMR (400 MHz, CDCl3): 8.34 (bs, 1H, OH),
8.14e8.34 (m, 2.6H, HAr), 7.37e7.61 (m, 16H, HAr), 5.61 (s, 1H, CH,
major), 5.41 (s, 0.25H, CH, minor), 5.36 (s, 0.25H, CH, minor), 5.28 (s,
Appendix A. Supplementary data
1H, CH, major) ppm. 13C NMR (101 MHz, CDCl3)
d 175.7, 171.6, 147.5
Supplementary data to this article can be found online at
https://doi.org/10.1016/j.tet.2019.05.025.
(2C), 136.96, 136.90, 135.4, 134.9, 132.7 (4C), 129.3 (4C), 129.1 (2C),
129.0 (2C), 128.9 (6C), 127.85 (2C), 127.82 (2C), 127.77 (2C), 127.6
(2C), 123.71 (2C), 123.68 (2C),91.3, 90.8, 86.9, 86.6, 78.3, 77.8, 71.1,
70.5 ppm. IR: 3065, 3030, 1721, 1593, 1344, 1107, 1067, 856,
References
750 cmꢀ1
.
[1] (a) K. Lamberth, F. Cederbaum, A. Jeanguenat, H.-J. Kempf, M. Zeller, R. Zeun,
Pest Manag. Sci. 62 (2006) 446e451;
ꢀ
ꢀ
ꢀ
(b) A. Ramírez-Villalvaa, D. Gonzalez-Calderona, C. Gonzalez-Romeroa,
4.5.8. 2-((3-(4-methoxyphenyl)-1-phenylprop-2-yn-1-yl)oxy)-2-
phenylacetic acid (7i)
ꢀ
ꢀ~
M. Morales-Rodríguezb, B. Jauregui-Rodríguez, E. Cuevas-Yanez, A. Fuentes-
Benítes, Eur. J. Med. Chem. 97 (2015) 275e279.
Yellow oil. 1H NMR (400 MHz, CDCl3): 8.99 (bs, 1H, OH),
7.64e7.66 (m, 2H, HAr), 7.55e7.59 (m, 1H, HAr), 7.49e7.51 (m, 2H,
[2] V.K. Chamberlain, R.L. Wain, Ann. Appl. Biol. 68 (1971) 307e311.
[3] G.Q. Shi, J.F. Dropinski, B.M. McKeever, S. Xu, J.W. Becker, J.P. Berger,
K.L. MacNaul, A. Elbrecht, G. Zhou, T.W. Doebber, P. Wang, Y.-S. Chao,
M. Forrest, J.V. Heck, D.E. Moller, A.B. Jones, J. Med. Chem. 48 (2005)
4457e4468.
[4] N.S. Cutshall, R. Onrust, A. Rohde, S. Gragerov, L. Hamilton, K. Harbol, H.-
R. Shen, S. McKee, C. Zuta, G. Gragerova, V. Florio, T.N. Wheeler, J.L. Gage,
Bioorg. Med. Chem. Lett 22 (2012) 5595e5599.
H
Ar), 7.35e7.44 (m, 10.7H, HAr), 6.83e6.87 (m, 2.7H, HAr),5.64 (s, 1H,
CH, major), 5.49 (s, 0.24H, CH, minor), 5.39 (s, 1H, CH, major), 5.37
(s, 0.25H, CH, minor) ppm. 13C NMR (101 MHz, CDCl3)
176.1, 174.4,
d
160.2, 160.1, 137.9, 137.8, 135.8, 135.2, 133.5 (4C), 129.4, 129.1, 129.0,
128.9, 128.85, 128.79 (4C), 128.75, 128.67 (4C), 128.0 (4C), 127.9,
127.6 (4C), 114.3, 114.12, 114.07 (4C), 89.4, 89.0, 84.4, 83.8, 78.1, 77.6,
71.5, 70.7, 55.4 (2C) ppm. IR: 3028, 3018, 1721, 1605, 1510, 1290,
1250, 1217, 756 cmꢀ1. MS (EI, 70 eV) m/z: 238 (16%); 237 (84); 222
(23); 221 (100); 178 (14); 105 (15); 77 (9).
[5] (a) A. Balsamo, P. Crotti, B. Macchia, F. Macchia, M. Del Tacca, L. Mazzanti,
J. Med. Chem. 16 (1973) 224e227;
(b) J.A. Gladding, J.P. Bacci, S.A. Shaw, A.B. Smith, Tetrahedron 67 (2011)
6697e6706;
c) M.E. Jung, Y.H. Jung, Y. Miyazawa, Tetrahedron Lett. 31 (1990) 6983e6986;
d) V.S. Martin, M.T. Nunez, C.E. Tonn, Tetrahedron Lett. 29 (1988) 2701e2702;
e) J. Mulzer, A. Angermann, Tetrahedron Lett. 24 (1983) 2843e2846;
f) B. Singh, P. Gupta, A. Chaubey, R. Parshad, S. Sharma, S.C. Taneja, Tetrahe-
dron: Asymmetry 19 (2008) 2579e2588.
4.5.9. 2-((3-(4-chlorophenyl)-1-phenylprop-2-yn-1-yl)oxy)-2-
phenylacetic acid (7j)
[6] (a) S.E. Denmark, L.R. Cullen, J. Org. Chem. 80 (2015) 11818e11848;
(b) M. Dickman, J.B. Jones, Bioorg. Med. Chem. 8 (2000) 1957e1968;
c) R.A. Moss, W.L. Sunshine, J. Org. Chem. 39 (1974) 1083e1089;
d) Y.-S. Hon, R.-C. Chang, T.-Y. Chau, Heterocycles 31 (1990) 1745e1750.
[7] T. Sugimura, T. Nagai, Chem. Lett. 37 (2008) 286e287.
[8] D. Seebach, R. Naef, G. Calderari, Tetrahedron Lett. 40 (1984) 1313e1324.
[9] (a) S.H. Mashraqui, R.M. Kellogg, J. Org. Chem. 49 (1984) 2513e2516;
(b) G.A. Kraus, B. Johnston, A. Kongsjahju, G.L. Tylka, J. Agric. Food Chem. 42
(1994) 1839e1840;
(c) S.E. Denmark, S.-M. Yang, J. Am. Chem. Soc. 124 (2002) 15196e15197.
[10] V.A. Shcherbinin, V.V. Konshin, Tetrahedron Lett. 59 (2018) 3005e3009.
[11] (a) R.A. Aitken, A. Meehan, L.A. Power, Synthesis 47 (2015) 1557e1559;
(b) R. Nagase, Y. Oguni, T. Misaki, Y. Tanabe, Synthesis 22 (2006) 3915e3917.
[12] (a) T.B. Cameron, F.M. El-Kabbani, H.W. Pinnick, J. Am. Chem. Soc. 103 (1981)
5414e5417;
Pale oil. 1H NMR (400 MHz, CDCl3): 8.61 (bs, 1H, OH), 7.60e7.60
(m, 2H, HAr), 7.52e7.52 (m, 1.5H, HAr), 7.47e7.50 (m, 2H, HAr),
7.35e7.42 (m, 11.6H, HAr), 7.28e7.30 (m, 2H, HAr), 5.61 (s, 1H, CH,
major), 5.41 (s, 0.34H, CH, minor), 5.36 (s, 0.34H, CH, minor), 5.31 (s,
1H, CH, major) ppm. 13C NMR (101 MHz, CDCl3)
d 175.9, 174.5, 137.5,
137.4, 135.6, 135.13, 135.09, 135.0, 133.2 (4C), 129.5, 129.13, 129.11,
129.0, 128.9 (4C), 128.80 (4C), 128.79 (4C), 127.9 (4C), 127.8 (2C),
127.6 (2C), 120.7, 120.6, 88.1, 87.7, 86.9, 86.4, 78.2, 77.7, 71.3,
70.6 ppm. IR: 3032, 2924, 1719, 1489, 1276, 1091, 827, 696 cmꢀ1. MS
(EI, 70 eV) m/z: 243 (9%); 241 (26); 227 (34); 226 (18); 225 (100);
189 (15); 164 (17).
(b) I. Chehidi, A.O. Amanetoullah, M.M. Chaabouni, A. Baklouti, J. Fluorine
Chem. 131 (2010) 66e69.
[13] (a) T. Watahiki, Y. Akabane, S. Mori, T. Oriyama, Org. Lett.
5
(2003)
4.5.10. 2-Phenyl-2-((1-phenyl-3-(trimethylsilyl)prop-2-yn-1-yl)
oxy)acetic acid (7k)
3045e3048;
ꢀ
ꢀ
(b) A. Rodríguez-Gimeno, A.B. Cuenca, J. Gil-Tomas, M. Medio-Simon,
A. Olmos, G. Asensio, J. Org. Chem. 79 (2014) 8263e8270.
Colourless crystals, mp 127e129ꢁС. 1H NMR (400 MHz, CDCl3):
9.96 (bs, 1H, OH), 7.57e7.59 (m, 2H, HAr), 7.49e7.53 (m, 1.5H, HAr),
7.35e7.47 (m, 10H, HAr), 5.45 (s, 1H, CH, major), 5.40 (s, 0.34H, CH,
minor), 5.32 (s, 1H, CH, major), 5.14 (s, 0.34H, CH, minor), 5.14 (s,
0.34H, CH, minor), 0.23 (s, 3H, CH3, minor), 0.21 (s, 9H, CH3, major)
[14] https://www.cup.lmu.de/oc/mayr/ReactScalesCnucl.pdf.
€
[15] D.E. Frantz, R. Fassler, C.S. Tomooka, E.M. Carreira, Acc. Chem. Res. 33 (2000)
373e381.
[16] (a) C.W. Downey, B.D. Mahoney, V.R. Lipari, J. Org. Chem. 74 (2009)
2904e2906;
(b) H.D. Srinivas, P. Maity, G.P.A. Yap, M.P. Watson, J. Org. Chem. 80 (2015)
4003e4016.
[17] K.B. Muchowska, S.J. Varna, E. Chevallot-Beroux, L. Lethuilier-Karl, G. Li,
J. Moran, Nat. Ecol. Evolut. 1 (2017) 1716e1721.
ppm. 13C NMR (101 MHz, CDCl3)
d 176.3, 174.4, 137.4, 137.2, 135.8,
135.1, 129.4, 129.1, 129.01, 128.97, 128.87 (2C), 128.78 (2C), 128.71
(2C), 128.6 (2C), 127.99 (2C), 127.94 (2C), 127.92 (2C), 127.6 (2C),