J.L. Zhu and K.A. Scheidt
Tetrahedron xxx (xxxx) xxx
1H), 6.78 (d, J ¼ 3.4 Hz, 1H), 4.33 (t, J ¼ 6.7 Hz, 2H), 3.91 (s, 3H), 3.69
4.46e4.35 (m, 2H), 3.90 (s, 3H), 3.68 (s, 3H), 3.67 (s, 2H),1.44 (s, 9H).
(s, 3H), 3.14 (t, J ¼ 6.7 Hz, 2H). 13C NMR (126 MHz, CDCl3)
d
170.6,
13C NMR (126 MHz, CDCl3)
d
170.3, 170.1, 166.8, 155.1, 138.6, 129.9,
166.8, 139.6, 138.9, 129.8, 129.3, 129.0, 126.8, 125.6, 124.0, 65.2, 52.1,
41.3, 29.1. FTIR (ATR) cmꢀ1: 2952, 1717, 1434, 1276, 1152, 1106, 1020,
698. HRMS (ESI/TOF) m/z: [MþH]þ Calcd. for C16H17O4S 305.0842;
Found 305.0846.
129.4, 80.4, 64.8, 52.8, 52.7, 52.1, 49.2, 41.0, 28.3. FTIR (ATR) cmꢀ1
:
3362, 2977, 2955,1743, 1715,1508,1436, 1278, 1158, 1108, 1020, 768.
HRMS (ESI/TOF) m/z: [MþH]þ Calcd. for C19H26NO8 396.1653;
Found 396.1649. Optical data: [
a
] [23](D) ꢀ25.0 (c, 0.90, MeOH).
4.5.19. methyl 4-(2-(4-methoxyphenethoxy)-2-oxoethyl)benzoate
4s
Prepared according to the general esterification procedure with
trifluoroborate 3f and ester 1f. Isolated as a clear oil (24 mg, 37%).
4.5.24. methyl 4-(2-(tert-butoxy)-2-oxoethyl)benzoate 4x
Prepared according to the general esterification procedure with
trifluoroborate 3f and ester 1k. Isolated as a clear oil (5 mg, 10%). 1H
NMR was consistent with literature data [33].
1H NMR (500 MHz, CDCl3)
d
7.98 (d, J ¼ 8.3 Hz, 2H), 7.30 (d,
J ¼ 8.3 Hz, 2H), 7.04 (d, J ¼ 8.6 Hz, 2H), 6.80 (d, J ¼ 8.6 Hz, 2H), 4.28
(t, J ¼ 6.9 Hz, 2H), 3.92 (s, 3H), 3.79 (s, 3H), 3.65 (s, 3H), 2.85 (t,
4.5.25. methyl 4-(2-(((3s,5s,7s)-adamantan-1-yl)oxy)-2-oxoethyl)
benzoate 4y
J ¼ 6.9 Hz, 2H). 13C NMR (126 MHz, CDCl3)
d
170.7, 166.8, 158.3,
Prepared according to the general esterification procedure with
139.1, 129.8, 129.5, 129.3, 129.0, 113.9, 65.7, 55.2, 52.1, 41.4, 34.1. FTIR
(ATR) cmꢀ1: 2953, 2837, 1720, 1613, 1584, 1513, 1435, 1278, 1246,
1179, 1157, 1108, 1034, 831. HRMS (ESI/TOF) m/z: [MþH]þ Calcd. for
trifluoroborate 3f and ester 1l. Isolated as a clear oil (18 mg, 27%). 1H
NMR (500 MHz, CDCl3)
d
7.99 (d, J ¼ 8.3 Hz, 2H), 7.34 (d, J ¼ 8.3 Hz,
2H), 3.91 (s, 3H), 3.57 (s, 2H), 2.14 (bs, 3H), 2.07 (d, J ¼ 3.0 Hz, 6H),
C
19H21O5 329.1384; Found 329.1384.
1.64 (bs, J ¼ 3.1 Hz, 6H). 13C NMR (126 MHz, CDCl3)
d 169.8, 167.0,
140.0, 129.7, 129.3, 128.8, 81.3, 52.0, 42.8, 41.2, 36.1, 30.8. FTIR (ATR)
cmꢀ1: 2911, 2853,1724,1279, 1254, 1107, 1055, 970. HRMS (ESI/TOF)
m/z: [MþH]þ Calcd. for C20H25O4 329.1747; Found 329.1753.
4.5.20. methyl 4-(2-oxo-2-((tetrahydro-2H-pyran-4-yl)methoxy)
ethyl)benzoate 4t
Prepared according to the general esterification procedure with
trifluoroborate 3f and ester 1g. Isolated as a clear oil (25 mg, 43%).
4.5.26. methyl 4-(2-oxo-2-((3-(trimethylsilyl)prop-2-yn-1-yl)oxy)
ethyl)benzoate 4z
1H NMR (500 MHz, CDCl3)
d
7.99 (d, J ¼ 8.3 Hz, 2H), 7.34 (d,
J ¼ 8.4 Hz, 2H), 3.97e3.92 (m, 4H), 3.90 (s, 3H), 3.67 (s, 2H), 3.35 (td,
J ¼ 11.8, 2.2 Hz, 2H), 1.92e1.82 (m, 1H), 1.54 (ddq, J ¼ 13.0, 4.0,
2.0 Hz, 2H), 1.32 (dtd, J ¼ 13.4, 11.9, 4.5 Hz, 2H). 13C NMR (126 MHz,
Prepared according to the general esterification procedure with
trifluoroborate 3f and ester 1m. Isolated as a clear oil (6 mg,10%). 1H
NMR (500 MHz, CDCl3)
d
8.00 (d, J ¼ 8.3 Hz, 2H), 7.36 (d, J ¼ 8.5 Hz,
CDCl3)
d 170.7, 166.8, 139.1, 129.8, 129.3, 129.0, 69.2, 67.3, 52.1, 41.3,
2H), 4.71 (s, 2H), 3.91 (s, 3H), 3.73 (s, 2H), 0.18 (s, 9H). 13C NMR
34.4, 29.4. FTIR (ATR) cmꢀ1: 2950, 2844, 1718, 1613, 1435, 1419,
(126 MHz, CDCl3) d 170.0,166.8,138.6,129.9,129.3,129.2, 98.6, 92.5,
1276, 1147, 1107, 1017, 853. HRMS (ESI/TOF) m/z: [MþH]þ Calcd. for
53.3, 52.1, 40.9, ꢀ0.4. FTIR (ATR) cmꢀ1: 2956, 1745, 1724, 1436, 1280,
C
16H21O5 293.1384; Found 293.1387.
1251, 1147, 1108, 845, 762. HRMS (ESI/TOF) m/z: [MþH]þ Calcd. for
C
16H21O4Si 305.1204; Found 305.1201.
4.5.21. methyl 4-(2-(cyclohexyloxy)-2-oxoethyl)benzoate 4u
Prepared according to the general esterification procedure with
trifluoroborate 3f and ester 1h. Isolated as a clear oil (33 mg, 60%).
4.5.27. methyl 4-(2-(((3S,8R,9S,10S,13S,14S)-10,13-dimethyl-17-
oxohexadecahydro-1H-cyclopenta[a]phenanthren-3-yl)oxy)-2-
oxoethyl)benzoate 4aa
Prepared according to the general esterification procedure with
trifluoroborate 3f and ester 1n. Isolated as an amorphous white
1H NMR (500 MHz, CDCl3)
d
7.99 (d, J ¼ 8.3 Hz, 2H), 7.36 (d,
J ¼ 8.7 Hz, 2H), 4.78 (tt, J ¼ 8.8, 3.9 Hz, 1H), 3.91 (s, 3H), 3.65 (s, 2H),
1.88e1.76 (m, 2H), 1.74e1.62 (m, 2H), 1.54e1.48 (m, 1H), 1.45e1.29
(m, 4H), 1.29e1.20 (m, 1H). 13C NMR (126 MHz, CDCl3)
d
170.3,
solid (27 mg, 29%). 1H NMR (500 MHz, CDCl3)
d
7.98 (d, J ¼ 8.3 Hz,
166.9, 139.6, 129.8, 129.3, 128.9, 73.4, 52.1, 41.8, 31.5, 25.3, 23.6. FTIR
(ATR) cmꢀ1: 2937, 2859, 1721, 1435, 1278, 1165, 1107, 1017, 742.
HRMS (ESI/TOF) m/z: [MþH]þ Calcd. for C16H21O4 277.1434; Found
277.1440.
2H), 7.34 (d, J ¼ 8.3 Hz, 2H), 4.70 (tt, J ¼ 11.4, 4.9 Hz,1H), 3.90 (s, 3H),
3.63 (s, 2H), 2.42 (ddd, J ¼ 19.3, 8.9, 1.1 Hz, 1H), 2.05 (dt, J ¼ 19.2,
9.1 Hz, 1H), 1.95e1.88 (m, 1H), 1.82e1.75 (m, 3H), 1.72 (dt, J ¼ 13.4,
3.7 Hz, 1H), 1.65e1.55 (m, 2H), 1.55e1.42 (m, 3H), 1.40e1.13 (m, 7H),
1.06e0.93 (m, 2H), 0.84 (s, 3H), 0.83, (s, 3H), 0.69 (ddd, J ¼ 12.0,
4.5.22. tert-butyl 4-(2-(4-(methoxycarbonyl)phenyl)acetoxy)
piperidine-1-carboxylate 4v
10.4, 4.0 Hz, 1H). 13C NMR (126 MHz, CDCl3)
d 170.3, 166.9, 139.5,
129.8, 129.2, 128.9, 74.2, 54.2, 52.0, 51.3, 47.7, 44.6, 41.7, 36.6, 35.8,
35.6, 35.0, 33.8, 31.5, 30.7, 28.2, 27.3, 21.7, 20.4, 13.8, 12.2. FTIR (ATR)
cmꢀ1: 2932, 2851,1734,1710,1276,1167,1106,1012, 727. HRMS (ESI/
TOF) m/z: [MþH]þ Calcd. for C29H39O5 467.2792; Found 467.2786.
Prepared according to the general esterification procedure with
trifluoroborate 3f and ester 1i. Isolated as an amorphous white
solid (17 mg, 23%). 1H NMR (500 MHz, CDCl3)
2H), 7.35 (d, J ¼ 8.6 Hz, 2H), 4.94 (tt, J ¼ 7.8, 3.8 Hz, 1H), 3.91 (s, 3H),
3.67 (s, 2H), 3.64e3.55 (m, 2H), 3.22 (ddd, J ¼ 13.6, 8.3, 3.7 Hz, 2H),
1.85e1.77 (m, 2H), 1.62e1.52 (m, 2H), 1.44 (s, 9H). 13C NMR
d
8.00 (d, J ¼ 8.3 Hz,
Optical data: [
a] [23](D) ꢀ72.7 (c, 0.42, MeOH).
4.5.28. methyl 4-(2-(((1R,2S,5R)-2-isopropyl-5-methylcyclohexyl)
oxy)-2-oxoethyl)benzoate 4 ab
Prepared according to the general esterification procedure with
trifluoroborate 3f and ester 1o. Isolated as an amorphous white
(126 MHz, CDCl3) d 170.1, 166.8, 154.6, 139.1, 129.9, 129.2, 129.1, 79.7,
70.4, 52.1, 41.6, 40.8, 30.4, 28.4. FTIR (ATR) cmꢀ1: 2976, 2949, 2926,
1721, 1680, 1416, 1358, 1271, 1180, 1163, 1107, 1019, 767, 726. HRMS
(ESI/TOF) m/z: [MþH]þ Calcd. for C20H28NO6 378.1911; Found
378.1913.
solid (27 mg, 41%). 1H NMR (500 MHz, CDCl3)
d
7.87 (d, J ¼ 8.3 Hz,
2H), 7.23 (d, J ¼ 8.4 Hz, 2H), 4.56 (td, J ¼ 10.9, 4.4 Hz, 1H), 3.79 (s,
3H), 3.53 (s, 2H),1.89e1.78 (m,1H),1.65e1.58 (m,1H),1.58e1.50 (m,
2H), 1.34 (ddtd, J ¼ 15.1, 12.0, 6.6, 3.1 Hz,1H), 1.22 (ddt, J ¼ 12.3, 10.8,
3.2 Hz, 1H), 0.91 (qd, J ¼ 13.4, 12.8, 3.8 Hz, 1H), 0.82 (td, J ¼ 12.1,
10.9 Hz, 1H), 0.74 (m, 7H), 0.56 (d, J ¼ 7.0 Hz, 3H). 13C NMR
4.5.23. methyl (S)-4-(2-(2-((tert-butoxycarbonyl)amino)-3-
methoxy-3-oxopropoxy)-2-oxoethyl)benzoate 4w
Prepared according to the general esterification procedure with
trifluoroborate 3f and ester 1j. Isolated as a clear oil (24 mg, 30%).
(126 MHz, CDCl3) d 170.3, 166.9, 139.5, 129.7, 129.2, 128.9, 75.0, 52.0,
1H NMR (500 MHz, CDCl3)
J ¼ 8.4 Hz, 2H), 5.20 (d, J ¼ 8.2 Hz, 1H), 4.55 (dd, J ¼ 8.3, 4.0 Hz, 1H),
d
8.00 (d, J ¼ 8.3 Hz, 2H), 7.32 (d,
47.0, 41.8, 40.7, 34.2, 31.3, 26.2, 23.4, 21.9, 20.6, 16.2. FTIR (ATR)
cmꢀ1: 2953, 2927, 2869, 1721, 1435, 1275, 1148, 1106, 985, 967, 724.
11