1 M HCl (5 ml) for 2 h followed by addition of sat. aq. NaHCO3
until neutral. The phases were separated and the aqueous phase
extracted with DCM (10 ml). The combined organic phases were
washed with 5% aq. Na2S2O3 and brine and dried over MgSO4.
Evaporation of solvent yielded 1.40 g crude that was purified by
column chromatography (DCM : Pentane : Et2O 7 : 3 : 0.5) to give
180 mg diastereomerically pure cis 12 (40%). Known compound,
spectral data were in accordance with those previously reported.19
(m, 2H, ArH), 7.35 (d, 1H, J = 8.1, ArH), 7.38–7.74 (m, 26H,
ArH); 13C NMR d: 20.8, 23.7 (d, JP = 4), 25.5, 26.2 (d, JP = 34,
CH2PPh2), 28.1, 29.6, 35.3, 36.4 (d, JP = 5), 42.6, 44.8 (d, JP = 6),
46.6, 47.3 (d, JP = 13), 67.4, 69.2, 77.4, 80.6 (d, JP = 18), 89.6 (d,
JP = 6), 117.6 (septet, JF = 4, BArF), 124.6, 124.7 (q, JF = 274,
BArF), 124.8, 129.0 (qq, JF = 32 and JB = 3, BArF), 129.4 (d, JP =
10), 129.8 (d, JP = 10), 130.0, 130.4 (d, JP = 9), 131.3 (d, JP = 3),
131.7, 132.2, 132.4, 133.4 (d, JP = 11), 134.9 (BArF), 137.0, 139.3,
143.5, 159.5, 160.3 (d. JP = 2), 161.8 (q, JB = 50, BArF); 31P NMR
d: 6.95
(5S,7S,8S)-8-(bromomethyl)-5,6,7,8-tetrahydro-6,6-dimethyl-2-
phenyl-5,7-methanoquinoline (16)
Diphenylphosphine–Ir complex (4)
Diastereomerically pure cis-alcohol 12 (260 mg, 0.98 mmol, 1.0 eq)
was dissolved in SOBr2 (2 ml) and the solution was heated to
110 ◦C under argon for 1.5 h. After cooling the reaction mixture
was carefully quenched with H2O and neutralized with sat. aq.
NaHCO3. The resulting suspension was extracted with DCM
and the organic phase shaken with 5% aq. Na2S2O3 and brine.
Drying over MgSO4 and evaporation of solvent gave 380 mg crude
bromide. Column chromatography (pentane to pentane : EtOAc
5 : 1) yielded 220 mg 16 as a light yellow oil (65%). Rf = 0.70
Boron-protected ligand 15 (30 mg, 0.07 mmol, 1.0 eq.) was
dissolved in freshly dried Et2NH (1 ml) and the resulting solution
stirred over night under argon. After evaporation of the Et2NH
the residue was filtered through a short plug of silica eluting with
toluene (Rf = 0.58). The product was dissolved in dry DCM
and [Ir(COD)Cl]2 (28 mg, 0.04 mmol, 0.55 eq.) was added. After
50 min reflux, the solution was cooled and water (1 ml) was added
followed by addition of NaBArF (75 mg, 0.09 mmol, 1.2 eq.). The
resulting solution was stirred vigorously for 1 h and the phases
were then separated. The organic phase was dried over MgSO4
and the solvent evaporated yielding 130 mg crude product. Flash
chromatography (DCM : Pentane 3 : 2) gave 35 mg (31%) 4 as
(pentane : EtOAc 5 : 1); [a]22.8 = + 79.1 (c 1.0, CHCl3); IR (neat)
D
mmax 2934, 2868, 1735, 1568, 1454, 1436, 1203, 1026, 849, 764, 742,
699; MS (EI) (m/z) (rel. int.) 342 (M, 39%), 298 (22%), 262 (100%),
248 (37%), 218 (36%), 206 (19%); 1H NMR d: 0.73 (s, 3H, 6-CH3),
1.42 (d, 1H, J = 9.0, 9-CH2), 1.49 (s, 3H, 6-CH3), 2.84 (m, 3H,
5-CH and 7-CH and 9-CH2), 3.60 (dd, 1H, J = 3.9 and 11.5, 8-
CH), 3.71 (t, 1H, J = 11.2, CH2Br), 4.64 (dd, 1H, J = 3.9 and
11.2, CH2Br), 7.32 (d, 1H, J = 7.8 ArH), 7.41 (m, 1H, ArH), 7.48
(m, 3H, ArH), 8.05 (m, 2H, ArH); 13C NMR d: 23.2, 26.9, 34.1,
36.6, 39.6, 42.6, 47.0, 51.3, 117.8, 126.6, 128.6, 128.8, 133.9, 139.4,
139.7, 154.5, 156.7;
a bright orange foam. Rf = 0.30 (Pentane:DCM 2:3); [a]21.2
=
D
1
+ 21.2 (c 1.0, CHCl3); H NMR d: 0.71 (s, 3H, 6-CH3), 1.10 (m,
3H), 1.47 (s, 3H, 6-CH3), 1.51 (d, 1H, J = 9.5, 9-CH2), 1.62–1.87
(m, 3H), 2.14 (m, 1H), 2.57–2.77 (m, 4H), 2.97 (m, 3H), 3.75 (m,
1H), 4.00 (t, 1H, J = 6.7, COD–CH), 4.37–4.53 (m, 2H), 7.15–
7.25 (m, 2H, ArH), 7.36 (d, 1H, J = 7.7, ArH), 7.39–7.75 (m,
26H, ArH); 13C NMR d: 23.6 (d, JP = 4), 24.4, 25.5 (d, JP = 34,
CH2PPh2), 26.9, 28.1, 35.5, 35.7, 36.4 (d, JP = 5), 41.2, 46.9, 47.7
(d, JP = 12), 48.8 (d, JP = 5), 68.9, 69.5, 79.0, 79.2, 89.3 (d, JP =
6), 117.6 (septet, JF = 4, BArF), 123.8, 124.5, 124.6 (q, JF = 272,
BArF), 129.0 (qq, JF = 31 and JB = 3,BArF), 129.3, 129.4, 129.9
(d, JP = 10), 130.2, 130.3 (d, JP = 9), 131.2 (d, JP = 2), 131.9,
132.4 (d, JP = 2), 133.6 (d, JP = 11), 134.9 (BArF), 137.0, 139.3,
144.2, 159.7, 160.0, 161.8 (q, JB = 50, BArF); 31P NMR d: 7.04
Diphenylphosphine–Ir complex (3)
Mg-filings (33 mg, 1.3 mmol, 4.0 eq.) were heated under vacuum
while stirring for 1 h, after cooling THF (2 ml) was added.
Compound 16 (110 mg, 0.34 mmol, 1 eq.) dissolved in THF
(1 ml) was added to the mixture and heated to 70 ◦C for 1 h.
The solution was allowed to cool and ClPPh2 (115 mg, 0.5 mmol,
1.5 eq.) was added dropwise. After stirring for 6 h at room
temperature, the solvent was removed and the residue filtered
through a short plug of silica eluting with toluene (Rf = 0.55). The
product (90 mg, 0.2 mmol, 1 eq.) was dissolved in dry DCM (5 ml)
and [Ir(COD)Cl]2 (75 mg, 0.11 mmol, 0.55 eq.) was added. The
solution was refluxed for 50 min and then allowed to cool. Water
(5 ml) and NaBArF (210 mg, 0.24 mmol, 1.2 eq.) was added and
the mixture stirred vigorously at room temperature. The phases
were then separated and the organic phase was dried over MgSO4
and evaporated yielding 300 mg crude. Flash chromatography
(Pentane : DCM 2 : 3) gave 110 mg pure complex 3 (20% overall
General procedure for preparation of complexes 5 and 6
Diphenylphosphinite–Ir complex (6). trans-Alcohol 18 (60 mg,
0.23 mmol, 1.0 eq.) was dissolved in THF (1 ml). After cooling
to 0 ◦C BuLi (0.16 ml, 0.25 mmol, 1.1 eq.) was slowly added.
After 20 min of stirring, ClPPh2 (0.045 ml, 0.25 mmol, 1.1 eq.)
was added dropwise and the solution was left to warm up to r.t.
over night. The solvent was evaporated and the residue dissolved
in DCM (5 ml). [Ir(COD)Cl]2 (85 mg, 0.15 mmol, 0.65 eq.) was
added and the solution refluxed under inert atmosphere for 1.5 h
and then allowed to cool. Water (4 ml) and NaBArF (250 mg,
0.28 mmol, 1.2 eq.) was added and the mixture stirred vigorously
for an hour. The phases were separated and the organic phase dried
over MgSO4 and evaporated to give a crude brown solid. Flash
chromatography (pentane : DCM 2 : 3) yielded 150 mg pure 6 as
yield). Rf = 0.31 (pentane : DCM 2 : 3); [a]21.2 = + 5.6 (c 1.0,
D
CHCl3); IR (neat) mmax 2947, 1610, 1438, 1354, 1280, 1160, 1124,
887, 839, 743, 682; 1H NMR d: 0.90 (s, 3H, 6-CH3), 1.11 (m, 3H,
COD–CH2), 1.37 (d, 1H, J = 11.1, 9-CH2), 1.53 (s, 3H 6-CH3),
1.55–1.74 (m, 2H), 1.86 (m, 2H), 2.12 (m, 1H), 2.12 (m, 1H), 2.43
(dd, 1H, J = 7.5 and 12.4, 8-CH), 2.60 (m, 2H, CH2PPh2), 2.80 (m,
2H), 2.98 (m, 2H), 4.20 (t, 1H, J = 7.2, COD–CH), 4.36 (t, 1H,
J = 13.7, CH2PPh2), 4.47 (t, 1H, J = 7.2, COD–CH), 7.16–7.25
an orange foam (41%). Rf = 0.40 (pentane : DCM 2 : 3); [a]22.8
=
D
−12.5 (c 1.0, CHCl3); IR (neat) mmax 2967, 1610, 1437, 1354, 1280,
1124, 981, 887, 839, 758, 713, 682; 1H NMR d: 0.85 (s, 3H, 6-CH3),
1.13 (m, 1H, COD–CH2), 1.26 (m, 2H, COD–CH2), 1.61 (s, 3H,
This journal is
The Royal Society of Chemistry 2007
Dalton Trans., 2007, 5603–5610 | 5609
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