1566
Y.-L. Chen, D. Hoppe / Tetrahedron: Asymmetry 20 (2009) 1561–1567
(m, 9H, Cb-CH3); 13C NMR (100 MHz, CDCl3): d/ppm 150.82 (C@O),
143.28 (Ts), 142.73 (Me–C@), 136.02 (Ph), 133.93 (Ts), 128.29 (2C,
Ts), 128.04 (2C, Ts), 127.42 (Ph), 127.26 (Ph), 127.22 (Ph), 126.37
(Ph), 125.86 (Ph), 111.65 (CH2@), 85.15 (Ts(OCb)CH), 51.47 (Ph(iso-
propenyl)CH), 45.54 (Cb), 45.07 (Cb), 20.52 (Ts), 20.07 (Cb), 19.93
(CH3), 19.76 (Cb), 19.16 (Cb), 19.05 (Cb).
separated and the water phase was washed several times with
diethyl ether. Each batch of the organic layers was filtered through
a silica gel plug and the combined organic layers were evaporated
to dryness. The residue containing 6 or 7 was analyzed by GC or
chiral HPLC.19
(b) For reactions using NHC ligand 12 in Table 2, entry 1 and Ta-
ble 3, entry 8, the triflate salt of ligand 12 (0.012 mmol, 4.6 mg)
was mixed with 2 mL of diethyl ether, cooled to ꢀ30 °C, and trea-
ted with the corresponding Grignard reagent (0.30 M in diethyl
ether, 0.05 mL, 0.015 mmol) used for the addition reaction. The
mixture was stirred at ꢀ30 °C for 30 min, and to this, copper source
(0.010 mmol, 5 equiv % of the sulfone) was then added. The result-
ing complex was again stirred at ꢀ30 °C for 30 min, and cooled to
the indicated reaction temperature followed by the addition of
a sulfone 5a or 5b solution in toluene (100 mg/mL, 0.8 mL,
0.20 mmol). To this cooled mixture, the Grignard reagent (0.30 M
in diethyl ether, 1.0 mL, 0.30 mmol, 1.5 equiv of the sulfone sub-
strate) was added dropwise over a period of 5 h by a syringe pump.
The mixture was then quenched and analyzed in the same way as
described in part (a).
4.4.2. 2-Phenyl-1-tosyl-pent-4-enyl N,N-diisopropylcarbamate
7
From carbamate 11 (50 mg, 0.17 mmol), with a TMEDA/s-BuLi
system, compound 7 (47 mg, 0.11 mmol, 61%) was obtained,
whose GC and 1H NMR match the reported data (from the diaste-
reomeric mixture);1 HRMS matches the calculated value; er on
C1 (R:S): 88.8:11.2; er on C2 (R:S): 97.2:2.8; ½a D20
¼ þ39:6 (c 1,
ꢃ
CHCl3). From carbamate 11 (50 mg, 0.17 mmol), with (ꢀ)-sparte-
ine/s-BuLi system, compound 7 (29 mg, 0.066 mmol, 38%) was ob-
tained, whose GC and 1H NMR match the reported data (from the
diastereomeric mixture);1 HRMS matches the calculated value; er
on C1 (R:S): 14.9:85.1; er on C2 (R:S): 96.3:3.7; [a]D = +21.7 (c 1,
CHCl3). The following interpretation of the analytical data of com-
pound 6b1 can then be derived: tR = 24.09 min (7a and ent-7a),
24.13 min (7b and ent-7b) (HP-5); Chiral HPLC: Eurocel 01
(c) For a reversed addition as described in Table 3, entry 4, the
reaction conditions are the same as described in part (a), except
that the allylmagnesium bromide was added at a time to the
cooled copper–ligand complex solution before the sulfone was
added dropwise over a period of 5 h. The mixture was then
quenched and analyzed in the same way as described in part (a).
(5
lm, 250 ꢂ 4.6 mm, Knauer), i-PrOH/n-hexane: 1:150, 0.6 mL/
min, 26 min (7a), 33 min (ent-7a); 40 min (7b), 45 min (ent-7b);
NMR of (7a and ent-7a): 1H NMR (400 MHz, CDCl3): d/ppm 7.53
(d, J = 8.3 Hz, 2H, Ts), 7.21–7.07 (m, 7H, Ts, Ph), 6.04 (d, J = 8.9 Hz,
1H, CH–O), 5.58–5.43 (m, 1H, CH@), 4.98–4.81 (m, 2H, CH2@),
3.75–3.68 (m, 1H, Cb), 3.64–3.57 (m, 1H, CH-Ph), 3.07–3.02 (m,
1H, Cb), 2.85–2.79 (m, 1H, CH2), 2.49–2.41 (m, 1H, CH2), 2.31 (s,
3H, Ts), 0.84 (d, J = 6.8 Hz, 3H, Cb), 0.74 (d, J = 6.8 Hz, 3H, Cb),
0.69 (d, J = 6.8 Hz, 3H, Cb), 0.57 (d, J = 6.8 Hz, 3H, Cb); 13C NMR
(100 MHz, CDCl3): d/ppm 150.24 (C@O), 144.57 (Ts), 138.80 (Ph),
134.59 (CH@), 134.25 (Ts), 129.37 (2C, Ts), 129.10 (2C, Ts),
128.67 (Ph), 128.43 (Ph), 128.14 (Ph), 127.25 (Ph), 126.93 (Ph),
117.03 (CH2@), 86.36 (CH–O), 46.58 (Cb), 46.01 (Cb), 44.40 (CH-
Ph), 35.38 (CH2), 21.55 (Ts), 20.15 (Cb), 20.00 (Cb), 19.85 (Cb),
19.71 (Cb); NMR of (7b and ent-7b): 1H NMR (400 MHz, CDCl3):
d/ppm 7.70 (d, J = 8.3 Hz, 2H, Ts), 7.21–7.07 (m, 7H, Ts and Ph),
6.00 (d, J = 6.2 Hz, 1H, CH–O), 5.58–5.43 (m, 1H, CH@), 4.98–4.81
(m, 2H, CH2@), 4.18–4.11 (m, 1H, Cb), 3.49–3.42 (m, 1H, Cb),
3.64–3.57 (m, 1H, CH-Ph), 2.99–2.93 (m, 1H, CH2), 2.59–2.51 (m,
1H, CH2), 2.29 (s, 3H, Ts), 1.18 (d, J = 6.8 Hz, 3H, Cb), 1.14 (d,
J = 6.8 Hz, 3H, Cb), 1.04 (d, J = 6.8 Hz, 3H, Cb), 0.90 (d, J = 6.8 Hz,
3H, Cb); 13C NMR (100 MHz, CDCl3): d/ppm 151.25 (C@O), 144.84
(Ts), 138.89 (Ph), 135.10 (CH@), 134.68 (Ts-S), 129.53 (2C, Ts),
129.41 (2C, Ts), 128.94 (Ph), 128.43 (Ph), 128.14 (Ph), 127.25
(Ph), 126.93 (Ph), 117.60 (CH2@), 87.97 (CH–O), 46.78 (Cb), 45.94
(Cb), 45.01 (CH-Ph), 37.06 (CH2), 21.55 (Ts), 21.21 (Cb), 20.93
(Cb), 20.13 (Cb), 19.98 (Cb).
Acknowledgments
We thank the group of Professor Dr. Frank Glorious for the kind
donation of the NHC ligand. Generous support by the Fonds der
Chemischen Industrie and Deutsche Forschungsgemeinschaft is
gratefully acknowledged.
References
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