RHODIUM(II)-CATALYZED REACTION OF SALICYLALDEHYDE
1775
Ethyl 2-methyl-1-benzofuran-3-carboxylate (5b)
(CH2CH3), 61.00 (OCH2CH3), 62.76 (C4′, C5′), 66.73
(OCH2CO), 110.79 (C2′); 122.60, 125.89, 125.97,
129.90, 135.91, 152.12 (Carom); 167.02 (C=O). Mass
spectrum, m/z (Irel, %): 252 (<1), 250 (4), 235 (18), 190
(66), 162 (100), 145 (70), 133 (22), 121 (15), 118 (30),
105 (14), 89 (20), 77 (25), 63 (12), 51 (12), 43 (76).
Found, %: C 61.87; H 6.32. C13H16O5. Calculated, %:
C 61.90; H 6.35.
[11]. Yield 0.08 g (33%), light yellow liquid, Rf 0.24
1
(petroleum ether–ethyl acetate, 8:2). H NMR spec-
trum, δ, ppm: 1.33 t (3H, CH2CH3, J = 7.1 Hz), 2.38 s
(3H, 2-CH3), 4.44 q (2H, OCH2, J = 7.1 Hz), 7.59 t
(1H, 6-H), 7.64 d (1H, 7-H), 7.80 t (1H, 5-H), 8.05 d
(1H, 4-H). 13C NMR spectrum, δC, ppm: 13.91
(CH2CH3), 13.99 (2-CH3), 59.08 (OCH2), 110.77 (C3),
114.63 (C7), 119.18 (C4), 126.15 (C5), 127.03 (C6),
129.87 (C3a), 152.78 (C7a), 163.66 (C2), 167.28 (C=O).
Mass spectrum, m/z (Irel, %): 204 (<1), 190 (90), 162
(98), 145 (100), 134 (14), 118 (50), 89 (76), 78 (10),
63 (28), 51 (3), 44 (16), 32(10).
Ethyl 2-[2-(1,3-dioxolan-2-yl)phenoxy]-3-oxo-
butanoate (7b). Yield 0.08 g (23%), light yellow
liquid, Rf 0.34 (petroleum ether–ethyl acetate, 8:2).
1H NMR spectrum, δ, ppm: 1.26 t (3H, CH2CH3, J =
7.3 Hz), 2.32 s (3H, COCH3), 3.48–3.52 m (4H, 4′-H,
5′-H), 4.24 q (2H, OCH2, J = 7.2 Hz), 4.58 s (1H,
OCHCO), 5.53 s (1H, 2′-H), 6.72 t (1H, Harom), 6.84 d
(1H, Harom), 7.15 t (1H, Harom), 7.84 d (1H, Harom).
13C NMR spectrum, δC, ppm: 14.04 (CH2CH3), 27.79
(COCH3), 62.73 (OCH2), 67.01 (C4′, C5′), 83.98
(OCHCO), 97.14 (C2′); 110.68, 125.99, 126.22,
126.43, 126.81, 158.53 (Carom); 165.36 (CO2C2H5),
200.09 (COCH3). Mass spectrum, m/z (Irel, %): 294
(<1), 281 (4), 233 (2), 221 (3), 207 (14), 190 (7), 164
(100), 145 (17), 133 (20), 121 (38), 105 (8), 91 (14),
87 (22), 77 (25), 73 (32), 65 (12), 44 (30), 36 (18), 32
(19). Found, %: C 61.18; H 6.09. C15H18O6. Calculat-
ed, %: C 61.22; H 6.12.
Ethyl 2-ethoxy-1-benzofuran-3-carboxylate (5c).
Yield 0.09 g (43%), light yellow liquid, Rf 0.27 (petro-
1
leum ether–ethyl acetate, 8:2). H NMR spectrum, δ,
ppm: 1.26 t (3H, COOCH2CH3, J = 7.1 Hz), 1.28 t
(3H, 2-OCH2CH3, J = 7.1 Hz), 4.18 q (2H, COOCH2,
J = 7.1 Hz), 4.25 q (2H, 2-OCH2, J = 7.1 Hz), 7.07 d
(1H, 7-H), 7.38 t (1H, 6-H), 7.49 t (1H, 5-H), 7.58 d
(1H, 4-H). 13C NMR spectrum, δC, ppm: 13.94
(COOCH2CH), 14.02 (2-OCH2CH3), 61.63 (COOCH2),
63.62 (2-OCH2), 111.83 (C3), 118.51 (C7), 118.94 (C4),
125.17 (C6), 125.65 (C5H), 126.01 (C3a), 157.29 (C7a),
165.88 (C=O), 166.85 (C2). Mass spectrum, m/z
(Irel, %): 234 (14), 207 (8), 190 (40), 179 (38), 162
(100), 145 (36), 133 (70), 120 (52), 105 (24), 89
(16), 77 (36), 63 (10), 51 (6), 44 (8), 32 (5). Found,
%: C 66.64; H 5.90. C13H14O4. Calculated, %: C 66.67;
H 5.99.
Diethyl [2-(1,3-dioxolan-2-yl)phenoxy]propane-
dioate (7c). Yield 0.08 g (26%), light yellow liquid,
1
Rf 0.31 (petroleum ether–ethyl acetate, 8:2). H NMR
spectrum, δ, ppm: 1.27 t (6H, CH2CH3, J = 7.2 Hz),
3.95–4.02 m (4H, 4′-H, 5′-H), 4.26 q (4H, OCH2, J =
7.2 Hz), 5.27 s (1H, COCHCO), 5.88 s (1H, 2′-H),
6.89 d (1H, Harom), 6.96 t (1H, Harom), 7.34 t (1H,
2-Ethoxy-4H-chromen-4-one (6) [11]. Yield
0.06 g (17%), light yellow liquid, Rf 0.34 (petroleum
1
ether–ethyl acetate, 8:2). H NMR spectrum, δ, ppm:
H
arom), 7.88 d (1H, Harom). 13C NMR spectrum, δC,
1.42 t (3H, CH2CH3, J = 7.1 Hz), 4.44 q (2H, OCH2,
J = 7.1 Hz), 6.92 s (1H, 3-H), 7.64 d (1H, 8-H), 7.26 t
(1H, 7-H), 7.83 t (1H, 6-H), 9.68 d (1H, 5-H).
13C NMR spectrum, δC, ppm: 14.10 (CH3), 61.62
(OCH2), 115.39 (C3), 117.19 (C8), 123.88 (C4a), 126.67
(C6), 127.84 (C5), 135.89 (C7), 156.09 (C8a), 165.21
(C=O), 173.36 (C4). Mass spectrum, m/z (Irel, %): 190
(90), 168 (3), 139 (8), 121 (100), 107 (3), 93 (31), 77
(6), 65 (30), 53 (4), 44 (8), 39 (14).
ppm: 13.95 (CH2CH3), 62.24 (OCH2), 67.05 (C4′, C5′),
79.09 (COCHCO), 98.95 (C2′); 113.71, 125.74,
125.98, 128.60, 130.03, 159.17 (Carom), 164.27 (C=O).
Mass spectrum, m/z (Irel, %): 324 (<1), 218 (3), 235
(9), 205 (55), 191 (7), 177 (64), 163 (10), 149 (8), 133
(100), 121 (36), 105 (16), 97 (8), 89 (16), 77 (20), 65
(12), 51 (5), 44 (16), 32 (18). Found, %: C 59.21;
H 6.15. C16H20O7. Calculated, %: C 59.26; H 6.17.
Ethyl [2-(1,3-dioxolan-2-yl)phenoxy]acetate (7a).
Ethyl [2-(1,3-dioxan-2-yl)phenoxy]acetate (8a).
Yield 0.21 g (54%), light yellow liquid, Rf 0.42 (petro-
leum ether–ethyl acetate, 8:2). H NMR spectrum, δ,
Yield 0.20 g (49%), light yellow liquid, Rf 0.34 (petro-
leum ether–ethyl acetate, 8:2). H NMR spectrum, δ,
1
1
ppm: 1.28 t (3H, CH2CH3, J = 7.2 Hz), 4.18–4.32 m
(4H, 4′-H, 5′-H), 4.37 q (2H, OCH2CH3, J = 7.1 Hz),
5.31 s (2H, OCH2CO), 5.84 s (1H, 2′-H), 6.88 d (1H,
Harom), 7.02 t (1H, Harom), 7.39 t (1H, Harom), 7.47 d
(1H, Harom). 13C NMR spectrum, δC, ppm: 14.07
ppm: 1.31 t (3H, CH2CH3, J = 7.1 Hz), 2.20–2.26 m
(2H, 5′-H), 4.04 t (2H, 4′-H, 6′-H), 4.25 q (2H,
OCH2CH3), 4.63 s (2H, OCH2CO), 5.64 s (1H, 2′-H),
6.76 d (1H, Harom), 7.04 t (1H, Harom), 7.26 t (1H,
H
arom), 7.64 d (1H, Harom). 13C NMR spectrum, δC,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 54 No. 12 2018