6 Orientating experiments with different
protecting groups on the alcohol were performed with TBS (5e/6e = 85:15),
Bn (5e/6e = 75:25),
Me (5e/6e = 70:30)
using conditions from Table
[¹]
,
entry 1.
8
Typical Procedure
for an Aza-Sakurai-Hosomi Reaction: In a dry flask
under argon were introduced 4 (0.756 mmol)
and R²NH2 (0.756 mmol) in anhydrous CH2Cl2 (4
mL, 0.2 M). The mixture was cooled to 0 ˚C by means of
an ice bath. Allylsilane (0.765 mmol) was then added followed by
a dropwise addition of a 1 M solution of BF3˙OEt2 in
CH2Cl2 (0.756 mmol). The reaction was stirred for
1 h at 0 ˚C before addition of sat. NaHCO3.
The organic layer was extracted with CH2Cl2 (3 ×)
and dried over Na2SO4. The solvent was removed
under reduced pressure and the residue was purified by silica gel
chromatography. Spectroscopic data for 6a:
IR(film): 2952, 2928, 2856, 1696, 1508, 1250 cm-¹. ¹H
NMR (200 MHz, CDCl3): δ = 7.23-7.39
(m, 10 H), 5.70-5.80 (m, 1 H), 5.05-5.21 (m, 5
H), 4.82 (dd, J = 2.0, 9.1 Hz,
1 H), 3.80-3.91 (m, 1 H), 2.26-2.40 (m, 2 H),
1.93 (ddd, J = 2.9, 10.0, 13.8
Hz, 1 H), 1.68 (br d, J = 9.1
Hz, 1 H), 0.88 (s, 9 H), 0.05 (s, 3 H), -0.26 (s, 3 H). ¹³C NMR
(75 MHz, CDCl3): δ = 155.9 (C), 145.0
(C), 136.9 (C), 134.5 (CH), 128.5 (CH), 128.3 (CH), 128.1 (CH),
128.0 (CH), 127.3 (CH), 125.9 (CH), 117.8 (CH2), 72.7
(CH), 66.5 (CH2), 48.4 (CH), 44.4 (CH2), 39.7
(CH2), 25.8 (Me), 18.1 (C), -4.5 (Me), -5.1
(Me). HRMS (ESI, positive, HCOOLi): m/z [M + Li] calcd
for C23H39NO3Si: 446.2698; found: 446.2690.
11
Typical Procedure
for Hydroformylation: In a dry Schlenk glassware under argon
were introduced Rh(CO)2acac (1 mol%) and anhydrous
degassed THF (1 mL). Biphephos (2 mol%) was added and CO
evolution was observed. Subsequent addition of homoallylic amide
(and PPTS) was performed. The mixture was transferred via a syringe
in a dry stainless autoclave under argon. The glassware was rinsed
with anhydrous degassed THF (3 ×) to reach a final concentration
of 0.04 M. The autoclave was purged (3 ×) with H2/CO
(1:1) before setting the pressure at 5 bar. The autoclave was heated
at 65 ˚C (internal temperature) by means of an oil bath.
Once the reaction was finished, the autoclave was depressurized
and the solvent was removed under reduced pressure. The residue
was purified by silica gel chromatography. Spectroscopic data for 7: IR(film): 2951, 2927, 2854, 1703, 1651,
1324, 1089, 1060, 833 cm-¹. ¹H
NMR (200 MHz, CDCl3): δ = 7.15-7.36 (m,
10 H), 6.79 (br d, J = 8.2 Hz,
0.5 H, rotamers), 6.66 (br d, J = 8.2
Hz, 0.5 H, rotamers), 5.16 (s, 2 H), 4.94 (m, 0.5 H, rotamers),
4.81 (m, 1 H), 4.65 (m, 0.5 H, rotamers), 4.45 (m, 0.5 H, rotamers),
4.14 (m, 0.5 H, rotamers), 1.72-2.13 (m,
6 H),
0.87, 0.85 (s, 9 H, rotamers), 0.1 (s, 1.5 H, rotamers), -0.03
(s, 1.5 H, rotamers), -0.24, -0.26 (s, 3 H, rotamers). ¹³C
NMR (50 MHz, CDCl3): δ = 153.2, 152.9
(rotamers, C), 145.3, 144.6 (rotamers, C), 136.5, 136.4 (rotamers,
C), 128.6 (CH), 128.5 (CH), 128.2 (CH), 128.0 (CH), 127.3 (CH), 126.2,
126.1 (rotamers, CH), 124.3, 123.7 (rotamers, CH), 106.2 (CH), 73.8
(CH), 67.4 (CH2), 49.1, 48.8 (rotamers, CH), 42.7 (CH2),
26.0 (Me), 25.5, 24.7 (rotamers, CH2), 18.2 (C), 17.8,
17.4 (rotamers, CH2), -4.5, -4.8 (rotamers,
Me). HRMS (ESI, positive, HCOOLi): m/z [M + Li] calcd
for C26H37NO3Si: 458.2698; found:
458.2685.
