LETTER
NMR (125 MHz, CDCl3): d = 11.8, 13.9, 19.0, 19.1, 33.5,
Synthesis of de novo Imidates
2401
J = 7.5 Hz), 7.44 (d, 2 H, J = 8.0 Hz), 7.75 (d, 2 H, J = 8.5
Hz). 13C NMR (125 MHz, CDCl3): d = 21.3, 21.4, 21.7, 38.1,
48.9, 72.5, 117.7, 126.8, 127.7, 128.7, 128.8, 129.5, 134.8,
137.9, 139.7, 143.1, 174.0. IR (film): 2984 (w), 1592 (s),
1302 (s), 1156 (s) cm–1. MS (APCI): m/e (%) = 330 (100)
[M – propene + H]+. ESI-HRMS: m/e calcd for
34.3, 64.8, 116.1, 124.2, 128.0, 137.3, 148.6, 179.5. IR
(film): 2943 (w), 2868 (w), 1566 (s), 1531 (s), 1295 (s), 1159
(s) cm–1. MS (APCI): m/e (%) = 469 (100) [M + H]+. ESI-
HRMS: m/e calcd for C22H36N2O5SSiNa: 491.2007; found:
491.2007.
Imidate 4f
C21H25NO3SNa: 394.1448; found: 394.1440.
Imidate 4k
Rf = 0.27 (hexanes–EtOAc, 15:1). 1H NMR (400 MHz,
CDCl3): d = 1.14 (d, 9 H, J = 7.2 Hz), 1.15 (d, 3 H, J = 6.4
Hz), 1.17 (d, 9 H, J = 7.6 Hz), 1.28 (d, 3 H, J = 6.4 Hz), 1.32
(sept, 3 H, J = 7.6 Hz), 2.46–2.52 (m, 1 H), 2.60 (dt, 1 H,
J = 14.4, 8.8 Hz), 3.61 (dd, 1 H, J = 12.0, 3.6 Hz), 4.93 (d, 1
H, J = 10.0 Hz), 4.96–5.04 (m, 2 H), 5.76 (dddd, 1 H,
J = 17.0, 10.0, 8.8, 5.2 Hz), 8.10 (d, 2 H, J = 9.2 Hz), 8.33
(d, 2 H, J = 8.8 Hz). 13C NMR (125 MHz, CDCl3): d = 11.8,
19.1, 19.1, 21.5, 21.8, 33.4, 34.4, 72.9, 116.1, 124.2, 128.0,
137.3, 148.7, 149.9, 178.9. IR (film): 2946 (m), 2869 (m),
1562 (s), 1531 (s), 1349 (s), 1296 (s), 1156 (s) cm–1. MS
(APCI): m/e (%) = 441 (30) [M – propene + H]+. ESI-
HRMS: m/e calcd for C23H38N2O5SSiNa: 505.2163; found:
505.2164.
Rf = 0.33 (hexanes–EtOAc, 4:1). 1H NMR (500 MHz,
CDCl3): d = 1.25 (t, 3 H, J = 7.0 Hz), 2.62 (dt, 1 H, J = 13.5,
7.0 Hz), 2.83 (dt, 1 H, J = 15.5, 8.5 Hz), 3.84 (s, 3 H), 4.09
(dq, 1 H, J = 11.0, 7.0 Hz), 4.18 (dq, 1 H, J = 11.0, 7.0 Hz),
4.99–5.04 (m, 2 H), 5.09 (d, 1 H, J = 17.0 Hz), 5.70–5.59 (m,
1 H), 6.91 (d, 2 H, J = 9.0 Hz), 7.26 (t, 1 H, J = 7.5 Hz), 7.32
(d, 2 H, J = 7.5 Hz), 7.45 (d, 2 H, J = 7.5 Hz), 7.81 (d, 2 H,
J = 9.0 Hz). 13C NMR (100 MHz, CDCl3): d = 13.7, 37.9,
48.8, 55.7, 64.8, 114.0, 117.7, 127.7, 128.8, 128.9, 128.9,
133.1, 134.9, 137.8, 162.9, 174.4. IR (film): 2986 (w), 1593
(s), 1499 (m), 1298 (s), 1150 (s) cm–1. MS (APCI):
m/e (%) = 374 (100) [M + H]+. ESI-HRMS: m/e calcd for
C20H23NO4SNa: 396.1231; found: 396.1240.
Imidate 4g
Imidate 4l
Rf = 0.36 (hexanes–EtOAc, 10:1). 1H NMR (400 MHz,
CDCl3): d = 1.13 (d, 9 H, J = 7.2 Hz), 1.16 (d, 9 H, J = 7.6
Hz), 1.33 (sept, 3 H, J = 7.6 Hz), 1.50–1.88 (m, 8 H), 2.46–
2.51 (m, 1 H), 2.58 (dt, 1 H, J = 14.0, 8.4 Hz), 3.60 (dd, 1 H,
J = 12.0, 3.2 Hz), 4.92 (d, 1 H, J = 10.0 Hz), 5.00 (d, 1 H,
J = 16.8 Hz), 5.09–5.14 (m, 1 H), 5.70–5.82 (m, 1 H), 8.11
(d, 2 H, J = 8.4 Hz), 8.33 (d, 2 H, J = 8.8 Hz). 13C NMR (125
MHz, CDCl3): d = 11.8, 19.1, 23.8, 24.1, 32.2, 32.9, 33.2,
34.4, 82.2, 116.0, 124.1, 128.0, 137.4, 148.7, 149.9, 179.1.
IR (film): 2947 (m), 2871 (m), 1565 (s), 1531 (s), 1349 (s),
1303 (m), 1157 (s) cm–1. MS (APCI): m/e (%) = 441 (30)
[M – cyclopentene + H]+. ESI-HRMS: m/e calcd for
C25H40N2O5SSiNa: 531.2320; found: 530.2333.
Imidate 4h
Rf = 0.20 (hexanes–EtOAc, 4:1). 1H NMR (500 MHz,
CDCl3): d = 1.55–1.83 (m, 8 H), 2.59 (dt, 1 H, J = 12.5, 6.5
Hz), 2.79 (dt, 1 H, J = 17.0, 8.0 Hz), 3.85 (s, 3 H), 4.99 (dd,
1 H, J = 9.0, 7.0 Hz), 5.02 (d, 1 H, J = 11.0 Hz), 5.09 (dd, 1
H, J = 17.0, 1.5 Hz), 5.12–5.17 (m, 1 H), 5.74 (dddd, 1 H,
J = 17.0, 10.0, 7.5, 5.5 Hz), 6.92 (d, 2 H, J = 9.0 Hz), 7.24–
7.28 (m, 1 H), 7.31 (t, 2 H, J = 7.0 Hz), 7.43 (d, 2 H, J = 7.5
Hz), 7.81 (d, 2 H, J = 9.0 Hz). 13C NMR (125 MHz, CDCl3):
d = 24.0, 32.4, 32.6, 38.0, 48.8, 55.8, 81.8, 114.0, 117.6,
127.7, 128.7, 128.8 128.8, 134.6, 134.9, 137.9, 162.7, 173.9.
IR (film): 2968 (w), 2850 (w), 1579 (s), 1294 (s), 1257 (s),
1150 (s) cm–1. MS (APCI): m/e (%) = 346 (100) [M –
cyclopentene + H]+. ESI-HRMS: m/e calcd for
C23H27NO4SNa: 436.1553; found: 436.1552.
Rf = 0.30 (hexanes–EtOAc, 4:1). 1H NMR (400 MHz,
CDCl3): d = 2.43 (s, 3 H), 3.59 (tt, 2 H, J = 6.0, 1.2 Hz), 3.69
(s, 3 H), 4.49 (t, 1 H, 6.0 Hz), 5.10 (ddt, 1 H, J = 10.4, 2.8,
1.6 Hz), 5.16 (ddt, 1 H, J = 17.2, 2.8, 1.6 Hz), 5.72 (ddt, 1 H,
J = 17.2, 10.4, 6.0), 7.24–7.34 (m, 7 H), 7.76 (d, 2 H, J = 8.4
Hz). 13C NMR (100 MHz, CDCl3): d = 21.6, 41.3, 45.8, 52.2,
117.7, 127.2, 127.3, 128.7, 129.4, 129.8, 133.2, 134.1,
137.1, 143.6, 172.2. IR (film): 3034 (m), 2951 (m), 1735 (s),
1597 (m), 1325 (s) cm–1. MS (APCI): m/e (%) = 344 (100)
[M + H]+. ESI-HRMS: m/e calcd for C19H21NO3SNa:
366.1135; found: 366.1150.
Imidate 15
Rf = 0.50 (hexanes–EtOAc, 4:1). 1H NMR (400 MHz,
CDCl3): d = 1.11 (d, 9 H, J = 7.6 Hz), 1.17 (d, 9 H, J = 7.6
Hz), 1.31 (sept, 3 H, J = 7.6 Hz), 2.41 (s, 3 H), 2.43–2.48 (m,
1 H), 2.61 (td, 1 H, J = 13.6, 8.8 Hz), 3.67 (dd, 1 H, J = 12.0,
3.2 Hz), 4.47 (dd, 1 H, J = 12.8, 6.0 Hz), 4.59 (dd, J = 12.8,
6.0 Hz), 4.87 (d, 1 H, J = 10.0 Hz), 4.95 (d, 1 H, J = 17.2
Hz), 5.22 (d, 1 H, J = 10.4 Hz), 5.28 (dd, 1 H, J = 16.0, 1.2
Hz), 5.63–5.74 (m, 1 H), 5.87 (ddt, 1 H, J = 16.8, 10.0, 6.0
Hz), 7.26 (d, 2 H, J = 8.0 Hz), 7.80 (d, 2 H, J = 8.4 Hz).
13C NMR (100 MHz, CDCl3): d = 11.8, 19.1, 21.7, 32.5,
34.2, 69.1, 115.9, 119.8, 126.8, 126.9, 129.4, 131.6, 137.4,
140.1, 142.9, 177.4 cm–1. IR (film): 2943 (m), 2869 (m),
1584 (s), 1302 (m), 1155 (s) cm–1. MS (APCI): m/e (%) =
450 (100) [M + H]+. ESI-HRMS: m/e calcd for
Imidate 4i
Rf = 0.48 (hexanes–EtOAc, 4:1). 1H NMR (500 MHz,
CDCl3): d = 1.26 (t, 3 H, J = 7.0 Hz), 2.41 (s, 3 H), 2.63 (dt,
1 H, J = 13.5, 6.5 Hz) 2.83 (dt, 1 H, J = 16.5, 8.0 Hz), 4.09
(dq, 1 H, J = 11.0, 7.0 Hz), 4.19 (dq, 1 H, J = 11.0, 7.0 Hz),
4.98–5.04 (m, 2 H), 5.10 (dd, 1 H, J = 17.0, 1.5 Hz), 5.70–
5.80 (m, 1 H), 7.23–7.28 (m, 3 H), 7.32 (t, 2 H, J = 8.0 Hz),
7.46 (d, 2 H, J = 7.5 Hz), 7.77 (d, 2 H, J = 8.0 Hz). 13C NMR
(125 MHz, CDCl3): d = 13.7, 21.7, 36.0, 37.9, 48.9, 64.6,
117.7, 126.9, 127.8, 128.8, 129.0, 129.5, 134.9, 137.8,
143.3, 174.6. IR (film): 2985 (w), 1592 (s), 1301 (s), 1152
(s) cm–1. MS (APCI): m/e (%) = 358 (100) [M + H]+. ESI-
HRMS: m/e calcd for C20H23NO3SNa: 380.1291; found:
380.1287.
C24H39NO3SSiNa: 472.2313; found: 472.2305.
Synthesis of Amide 16
To a stirring solution of imidate 15 (35.0 mg, 0.078 mmol)
in DCE (0.4 mL) was added PdCl2(PhCN)2 (1.5 mg, 0.004
mol). The reaction was stirred under a nitrogen atmosphere
for 3 h at r.t., and then the solvent was removed by rotary
evaporation. The crude residue was purified by flash silica
gel column chromatography [isocratic eluent: hexanes–
EtOAc, 20:1] to afford the amide 16 (35.0 mg, 0.078 mmol,
>95% yield) as a colorless oil.
Imidate 4j
Rf = 0.50 (hexanes–EtOAc, 4:1). 1H NMR (400 MHz,
CDCl3): d = 1.05 (d, 9 H, J = 6.8 Hz), 1.11 (d, 9 H, J = 6.8
Hz), 1.13–1.25 (m, 3 H), 2.26 (dd, 1 H, J = 11.6, 6.4 Hz),
2.43 (s, 3 H), 2.66 (td, 1 H, J = 13.2, 7.2 Hz), 3.00 (br s, 1 H),
4.34 (dd, 1 H, J = 16.4, 6.8 Hz), 4.47–4.54 (m, 1 H), 4.69 (d,
1 H, J = 10.0 Hz), 4.82 (d, 1 H, J = 16.8 Hz), 5.21 (d, 1 H,
Rf = 0.32 (hexanes–EtOAc, 6:1). 1H NMR (500 MHz,
CDCl3): d = 1.14 (d, 3 H, J = 6.0 Hz), 1.25 (d, 3 H, J = 6.5
Hz), 2.40 (s, 3 H), 2.59 (dt, 1 H, J = 12.5, 5.5 Hz), 2.80 (dt,
1 H, J = 14.5, 8.5 Hz), 4.97 (m, 3 H), 5.10 (d, 1 H, J = 17.5
Hz), 5.70–5.79 (m, 1 H), 7.22–7.27 (m, 3 H), 7.31 (t, 2 H,
Synlett 2010, No. 16, 2397–2402 © Thieme Stuttgart · New York