Communications
reaction mixture was heated at reflux for 2.5 h then allowed to cool to
329.2167; Elemental analysis calcd for C20H31NOSi (329.56): C 72.89,
H 9.48, N 4.25; found: C 73.36, H 9.71, N 3.91.
room temperature before diethyl ether (150 mL) was added, and the
resulting precipitate was filtered. The solvents were removed from the
filtrate in vacuo, and the residue was flash chromatographed on silica
gel to give analytically pure 3b (239 mg, 85% yield) as a pale yellow
oil, Rf = 0.59 (hexane/diethyl ether 1:1). 1H NMR (CDCl3, 500 MHz):
d = À0.17 (s, 9H), 2.34 (s, 3H), 2.50–2.55 (m, 1H), 2.76–2.81 (m, 1H),
2.93 (ddd, J = 1.6, 9.7, 17.8 Hz, 1H), 3.68–3.72 (m, 1H), 3.81 (dd, J =
1.6, 11.3 Hz, 1H), 4.08 (d, J = 17.1 Hz, 1H), 4.20 (dd, J = 2.3, 17.2 Hz,
1H), 6.97–7.01 (m, 2H), 7.10–7.14 (m, 2H), 9.86–9.87 ppm (m, 1H);
13C NMR (CDCl3, 125.8 MHz): d = 0.2 (CH3), 21.1 (CH3), 31.2 (CH),
46.8 (CH2), 67.3 (CH2), 70.6 (CH2), 128.5 (CH), 128.7 (CH), 133.8
(Cquat.), 137.2 (Cquat.), 137.4 (Cquat.), 149.5 (Cquat.), 201.5 ppm (CH);
HRMS calcd for C17H24O2Si: 288.1546, found: 288.1543; Elemental
analysis calcd for C17H24O2Si (288.5): C 70.78, H 8.39; found: C 70.61,
H 8.43.
Heck carbopalladation/cyclization/Wittig sequence (10b): In a
50-mL screw-top pressure vessel [Pd(PPh3)2Cl2] (14 mg, 0.02 mmol)
was dissolved in degassed triethylamine (10 mL). Then, 1a (198 mg,
1.00 mmol) and 2b (241 mg, 1.10 mmol) were added successively to
the solution. The reaction mixture was heated at reflux for 2.5 h then
allowed to cool to room temperature before THF (5 mL) and 9
(523 mg, 1.50 mmol) were added successively, and the reaction
mixture was stirred at room temperature for 18 h. The precipitates
were removed by filtration, the solvents were removed from the
filtrate in vacuo, and the residue was flash chromatographed on silica
gel to give the analytically pure 10b (301 mg, 86%) as a yellow oil,
Rf = 0.72 (hexane/diethyl ether 1:1). 1H NMR (CDCl3, 250 MHz): d =
À0.16 (s, 9H), 1.30 (t, J = 7.1 Hz, 3H), 2.23–2.61 (m, 6H), 3.58–3.66
(m, 1H), 3.81 (dd, J = 1.9, 11.2 Hz, 1H), 4.02–4.26 (m, 4H), 5.92 (dt,
J = 1.4, 15.6 Hz, 1H), 6.91–7.15 ppm (m, 5H); 13C NMR (CDCl3,
75.5 MHz): d = 0.4 (CH3), 14.2 (CH3), 21.1 (CH3), 35.2 (CH2), 36.0
(CH), 60.1 (CH2), 66.0 (CH2), 70.5 (CH2), 122.8 (CH), 128.6 (CH),
128.7 (CH), 134.5 (Cquat.), 137.1 (Cquat.), 137.6 (Cquat.), 147.1 (CH),
149.2 (Cquat.), 166.4 ppm (Cquat.); HRMS calcd for C21H30O3Si:
358.1964, found: 358.1950; Elemental analysis calcd for C21H30O3Si
(358.6): C 70.35, H 8.43; found: C 70.31, H 8.42.
Heck carbopalladation/cyclization/reductive amination sequence
(12b): In a 50-mL screw-top pressure vessel [Pd(PPh3)2Cl2] (28 mg,
0.04 mmol) was dissolved in a mixture of degassed 1,2-dichloroethane
(10 mL) and triethylamine (202 mg, 2.00 mmol). Then, 1a (198 mg,
1.00 mmol) and 2c (240 mg, 1.10 mmol) were added successively to
the solution. The reaction mixture was heated at reflux for 3 h then
allowed to cool to room temperature before formic acid (552 mg,
12.0 mmol) and pyrrolidine (11b) (356 mg, 5.00 mmol) were added
successively, and the reaction mixture was heated to 608C for 12 h.
The reaction mixture was allowed to cool to room temperature,
diethyl ether (150 mL) and anhydrous potassium carbonate were
added, and the precipitates were removed by filtration. The solvents
were removed from the filtrate in vacuo, and the residue was flash
chromatographed on basic alumina (Brockmann activity IV) to give
the analytically pure 12b (261 mg, 79%) as a yellow-red oil, Rf = 0.31
(hexane/diethyl ether 1:2). 1H NMR (CDCl3, 500 MHz): d = À0.22 (s,
9H), 1.67–1.85 (m, 6H), 2.09–2.18 (m, 1H), 2.42–2.60 (m, 6H), 3.60–
3.67 (m, 1H), 3.83 (dd, J = 2.2, 11.0 Hz, 1H), 4.04 (d, J = 16.9 Hz, 1H),
4.20 (dd, J = 2.2, 16.9 Hz, 1H), 7.04–7.11 (m, 2H), 7.20–7.30 ppm (m,
3H); 13C NMR (CDCl3, 125.8 MHz): d = 0.4 (CH3), 23.4 (CH2), 31.5
(CH2), 35.3 (CH), 54.3 (CH2), 54.9 (CH2), 66.8 (CH2), 70.4 (CH2),
127.2 (CH), 127.9 (CH), 128.8 (CH), 135.8 (Cquat.), 141.0 (Cquat.),
148.2 ppm (Cquat.); HRMS calcd for C20H31NOSi: 329.2175, found:
Received: June 30, 2004
À
Keywords: amination · C C coupling · domino reactions ·
multicomponent reactions · olefination
.
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6000 ꢀ 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2004, 43, 5997 –6000