[RhCl(dppmet-P)] 5e. To a solution of compound 1e
(110 mg, 319 µmol) in CH2Cl2 (10 cm3) was added [RhCl(cod)]2
(74 mg, 150 µmol). The solution was stirred for 20 min and then
concentrated in vacuo to about 0.5 cm3. Separation with column
chromatography (silica gel, solvent Et2O) and removal of
solvent in vacuo afforded an orange flaky solid in yield of 66 mg
(37%).
yield of 2.97 g (90%). Slow diffusion of light petroleum into the
CH2Cl2 solution for one week gave colourless crystals suitable
for X-ray analysis.
(S)-N,N-Bis(diphenylthiophosphinoyl)alanine methyl ester
(bdppalS2) 13. To a solution of compound 7 (1.063 g, 2.257
mmol) in THF (80 cm3) was added sulfur (145 mg, 4.52 mmol).
The solution was stirred under N2 at reflux for 8 days. The
reaction mixture was concentrated to ca. 0.5 cm3. Separation
with column chromatography (silica gel, ethyl acetate–light
petroleum (bp 60–80 ЊC) 1:1) and removal of the solvent
in vacuo afforded a white floppy solid in yield of 0.882 g
(73%).
[AuCl(dppal-P)] 6a. To a solution of compound 1a (78 mg,
274 µmol) in CH2Cl2 (20 cm3) was added [AuCl(tht)] (86 mg,
268 µmol). The reaction mixture was stirred in darkness for
30 min and then concentrated in vacuo to dryness. Addition of
Et2O (1 cm3) and filtration in darkness gave a pink powder
(56 mg). Addition of light petroleum (3 cm3) to the filtrate
afforded another portion of product (67 mg). The total yield
was 123 mg (88%).
(S)-N-(Diphenylphosphino)-N-(diphenylphosphinoyl) alanine
methyl ester (bdppalO) 10 and cis-[PdCl2(bdppalO-P,O)] 14. To
a solution of compound 7 (99 mg, 210 µmol) in THF (5 cm3)
was added H2O2 (30%, 0.036 cm3, 315 µmol). The solution was
stirred at 0 ЊC for about 25 min and then stood at room tem-
perature until the 31P-{1H} NMR spectrum showed no peak at
δ 55.0 for 7. The dioxidised compound 12 (δP 31.0 in THF) was
unavoidable but it did not affect the co-ordination of 10 with
[PdCl2(cod)]. 25 mg (88 µmol) of [PdCl2(cod)] was added. The
reaction mixture was stirred for 30 min and then light petrol-
eum (40 cm3) was carefully layered. Its slow diffusion into the
THF solution in 10 h afforded orange crystals of complex 14 in
yield of 32 mg (55%). Compound 10 cannot be isolated from
the reaction mixture but can be observed as an intermediate by
the 31P-{1H} NMR spectrum (δ 45.8(d, PIII), 33.1 (d, P᎐O), 2J
(S)-N,N-Bis(diphenylphosphino)alanine methyl ester (bdppal)
7. To a solution of (S)-alanine methyl ester hydrochloride
(5.230 g, 37 mmol) in CH2Cl2 (100 cm3) was added Et3N
(16 cm3, 115 mmol). A CH2Cl2 (50 cm3) solution of Ph2PCl
(13.3 cm3, 74 mmol) was added dropwise. Stirring was con-
tinued for 3 h. The solution was concentrated in vacuo to dry-
ness. 100 cm3 of THF were added. The THF solution was fil-
tered through a sintered frit and the residue washed with THF
(3 × 30 cm3). The filtrate was rotatory evaporated to dryness to
give a slightly yellow sticky oil. 2 cm3 of MeOH were added and
a white solid precipitated. This was filtered off, washed with
cold MeOH ( 3 × 10 cm3) and cold Et2O ( 3 × 3 cm3) and dried
in vacuo. Yield: 11.0 g (63%).
᎐
PP
80 Hz). Slow evaporation of the CDCl3 solution gave red
crystals suitable for X-ray analysis.
cis-[PdCl2(bdppal-P,PЈ)] 8. To a solution of [PdCl2(cod)]
(33 mg, 116 µmol) in CH2Cl2 (5 cm3) was added compound 7
(55 mg, 117 µmol). The reaction mixture was stirred for 20 min
and then concentrated to ca. 1 cm3. Addition of Et2O (5 cm3)
led to a light green powder which was filtered off, washed with
Et2O (3 × 0.5 cm3), light petroluem (bp 40–60 ЊC, 3 × 1 cm3),
Et2O (3 × 0.5 cm3) and dried in vacuo to give a yield of 75 mg
(100%). Slow diffusion of light petroleum into the CH2Cl2
solution in three days gave pale yellow crystals suitable for
X-ray analysis.
cis-[PdCl2(bdppalS-P,S)] 15. To a solution of compound 11
(73 mg, 145 µmol) in CH2Cl2 (5 cm3) were added 40 mg
(141 µmol) of [PdCl2(cod)]. The reaction mixture was stirred
for 30 min and then concentrated in a rotatory evaporator to
ca. 1 cm3. Et2O (5 cm3) was added to give a light brown powder.
The product was filtered off, washed with Et2O (3 × 1 cm3) and
then dried in vacuo to give a yield of 95 mg (99%).
cis-[PtCl2(bdppalS-P,S)] 16. To a solution of compound 11
(69 mg, 137 µmol) in CH2Cl2 (5 cm3) were added 51 mg
(136 µmol) of [PtCl2(cod)]. The reaction mixture was stirred for
2 h and then concentrated in a rotatory evaporator to ca. 0.5
cm3. Et2O (5 cm3) was added to give a green-yellow powder. The
product was filtered off, washed with Et2O (3 × 1 cm3) and then
dried in vacuo to give a yield of 101 mg (98%).
cis-[PtCl2(bdppal-P,PЈ)] 9. To a solution of compound 7
(64 mg, 135 µmol) in CH2Cl2 (50 cm3) was added [PtCl2(cod)]
(50 mg, 134 µmol). The reaction mixture was stirred for 2 h
and then concentrated to ca. 1 cm3. Addition of Et2O (5 cm3)
led to a white powder (102 mg). The crude product was
dissolved in THF (50 cm3). Slow evaporation of THF in
20 days gave crystals suitable for X-ray analysis, yield 90 mg
(90.5%).
cis-[PdCl2(bdppalS2-S,SЈ)] 17. To a solution of compound 13
(78 mg, 145 µmol) in CH2Cl2 (5 cm3) were added 40 mg (141
µmol) of [PdCl2(cod)]. The reaction mixture was stirred for 2 h
and then concentrated in a rotatory evaporator to ca. 0.5 cm3.
Et2O (5 cm3) was added to give a brown powder. The product
was filtered off, washed with Et2O (3 × 1 cm3) and then dried
in vacuo to give a yield of 100 mg (100%).
(S)-N-(Diphenylphosphino)-N-(diphenylthiophosphinoyl)-
alanine methyl ester (bdppalS) 11. To a solution of compound 7
(1.544 g, 3.278 mmol) in THF (20 cm3) was added 213 mg (6.74
mmol) of sulfur. The solution was stirred overnight at room
temperature and then concentrated in vacuo to dryness. Et2O
(20 cm3) was added and unchanged sulfur removed by filtration.
The filtrate was concentrated in vacuo to dryness. Addition of
Et2O (2 cm3) to the floppy solid afforded a white powder in yield
of 0.653 g (40%). Slow diffusion of light petroleum into the
CH2Cl2 solution in two days gave colourless crystals suitable for
X-ray analysis.
X-Ray crystallography
Details of the data collections and refinements are summarised
in Table 12. Data were collected at room temperature using
Mo-Kα radiation with a SMART system. Intensities were
corrected for Lorentz-polarisation and for absorption. The
structures were solved by the heavy atom method or by direct
methods. The positions of the hydrogen atoms were idealised.
Refinements were by full-matrix least squares based on F2 using
SHELXTL.16 There was some disorder in complex 14. C(4) was
refined anisotropically in two 50% occupancy sites.
(S)-N,N-Bis(diphenylphosphinoyl)alanine
methyl
ester
(bdppalO2) 12. To a solution of compound 7 (3.088 g, 6.556
mmol) in THF (80 cm3) was added anhydrous MgSO4 and H2O2
(30%, 1.5 cm3, 13.2 mmol). The solution was stirred at 0 ЊC for
two hours and then filtered. The filtrate was dried in vacuo to
give a sticky gum. Addition of Et2O (2 cm3) afforded a white
powder. The powder was filtered and dried in vacuo to give a
CCDC reference numbers 152782–152787.
lographic data in CIF or other electronic format.
J. Chem. Soc., Dalton Trans., 2001, 621–632
623