Carbon-Sulfur Bond-Forming ReductiVe Elimination
J. Am. Chem. Soc., Vol. 120, No. 36, 1998 9217
(m, 8H), 7.70 (t, 7.8 Hz, 2H), 8.10 (td, 7.1, 1.4, 4H); 31P{1H} NMR
(C6D6) δ 33.89 (d, 24.2 Hz), 44.19 (d, 24.2 Hz).
NMR (C6D6) δ 1.54 (s, 3H), 1.76 (s, 3H), 1.82 (broad s, 4H), 1.97 (s,
9H), 6.5 (dd, Jtrans ) 11.4 Hz, Jcis ) 8 Hz, 1H), 6.93-7.12 (m, 16H),
8.05 (virtual t, 9.0 H, 4H); 31P{1H} NMR (THF) δ 42.3 (d, 23 Hz),
31.5 (d, 23 Hz).
[Pd(Ph2PCH2CH2PPh2)(S-t-Bu)(2,4-(CH3)2C6H3)] (10). The prod-
uct was obtained in 55.2% (48.6 mg) yield after crystallization by
layering a toluene solution with pentane at -35 °C. 1H NMR (C6D6)
δ 1.44 (m, 2H), 1.65 (s, 9H), 1.91 (m, 2H), 2.17 (s, 3H), 2.44 (s, 3H),
6.56 (d, 8 Hz, 1H), 6.57 (virtual t, 9 Hz, 2H), 6.71 (s, 1H), 6.78 (td, Jt
) 8 Hz, Jd ) 2.1 Hz, 2H), 6.89-7.13 (m, 1H), 7.70-7.73 (m, 3H),
8.06 (virtual t, 9 Hz, 2H), 8.22 (virtual t, 9 Hz, 2H); 31P{1H} NMR
(C6D6) δ 40.3 (d, 26 Hz), 31.3 (d, 26 Hz).
[Pd(Ph2PCH2CH2PPh2)(S-t-Bu)(3,4-(CH3)2C6H3)] (11). The prod-
uct was obtained in 55.2% (84.5 mg) yield after crystallization by
layering a toluene solution with pentane at -35 °C. 1H NMR (C6D6)
δ 1.66 (s, 9H), 1.70-1.94 (m, 4H), 1.94 (s, 3H), 2.06 (s, 3H), 6.79
(dd, 2.2 Hz, 7.5 Hz, 1H), 6.85-7.28 (m, 17H), 7.54 (t, 7.6 Hz, 1H),
8.12 (dd, 13.3 Hz, 8 Hz, 4H); 31P{1H} NMR (C6D6) δ 42.5 (d, 24 Hz),
31.7 (d, 24 Hz).
[Pd(Ph2PCH2CH2PPh2)(S-t-Bu)(2,6-(CH3)2C6H3)] (12). The prod-
uct was obtained in 70.4% (92.3 mg) yield after crystallization by
layering a toluene solution with pentane at -35 °C. 1H NMR (C6D6)
δ 1.58 (s, 9H), 1.62-1.84 (m, 4H), 2.65 (s, 6H), 6.78-6.92 (m, 6H),
6.95 (m, 4H), 7.05-7.12 (m, 9H), 8.23 (dd, 9.9 Hz, 8 Hz, 4H); 31P-
{1H} NMR (C6D6) δ 39.2 (d, 27 Hz), 27.4 (d, 27 Hz).
[Pd(Ph2PCH2CH2PPh2)(S-t-Bu)(CC(CH2)3CH3)] (16). To a 20 mL
vial was weighed 192.9 mg (0.2708 mmol) of [Pd(DPPE)(CC(CH2)3-
CH3)(I)]. This solid was suspended in 2 mL of THF. A suspension
of 2-methyl-2-propanethiol, sodium salt (45.2 mg, 0.136 mmol) in 5
mL of THF was added and the resulting dark orange mixture was stirred
for 1 h at room temperature. After this time, the THF solvent was
evaporated under vacuum. The residual solid was dissolved in benzene
and the mixture was filtered through Celite. The product was obtained
as a crystalline orange solid by layering a toluene solution with pentane
at -35 °C (158 mg, 86.5%). 1H NMR (C6D6) δ 0.79 (t, 7 Hz, 3H),
1.28-1.42 (m, 4H), 1.69-1.89 (m, 4H), 2.22 (s, 9H), 2.34 (t, 6 Hz,
2H), 7.00-7.03 (m, 12H), 7.84-7.92 (m, 8H); 31P{1H} NMR (C6D6)
δ 47.1 (d, 22 Hz), 44.3 (d, 22 Hz); IR (KBr, cm-1) 2120 (w).
[Pd(Ph2PCH2CH2PPh2)(S-t-Bu)(CCC6H5)] (17). The product was
obtained in 48.2% (48.8 mg) yield after crystallization by layering a
toluene solution with pentane at -35 °C. 1H NMR (C6D6) δ 1.77-
1.82 (m, 4H), 2.21 (s, 9 H), 6.92-7.35 (m, 15H), 7.33 (d, 7.3 Hz, 2H),
7.85 (m, 8H); 31P{1H} NMR (C6D6) δ 48.1 (d, 22 Hz), 45.1 (d, 22
Hz); IR (KBr, cm-1) 2100 (w).
[Pd(Ph2PCH2CH2PPh2)(SMe)(C6H4-4-Cl)] (13). The product was
obtained in 61.7% (86.7 mg) yield after crystallization by layering a
toluene solution with pentane at -35 °C. 1H NMR (C6D6) δ 1.64-
1.95 (m, 4 H), 2.22 (d, 5.6 Hz, 3H), 6.82-7.17 (m, 18H), 7.36 (t, 7.5
Hz, 2H), 8.07 (m, 4H); 31P{1H} NMR (C6D6) δ 36.39 (d, 25.4 Hz),
43.43 (d, 25.4 Hz).
[Pd(Ph2PCH2CH2PPh2)(SCH3)(CH3) (18)]. The product was ob-
tained in 53.3% (53.6 mg) yield after crystallization by layering a THF
solution with ether at -35 °C. 1H NMR (C7D8) δ 0.97 (dd, 6 Hz, 7
Hz, 3H), 1.74-1.95 (m, 4H), 2.58 (d, 6 Hz, 3H), 7.30-7.36 (m, 12H),
7.49 (virtual t, 9.8 Hz, 4H), 8.00 (virtual t, 10 Hz, 4H); 31P{1H} NMR
(C7D8) δ 50.4 (d, 23 Hz), 35.8 (d, 23 Hz).
[Pd(Ph2PCH2CH2PPh2)(S-t-Bu)(CH3)] (14). To a 20 mL vial was
added 413.0 mg (0.7441 mmol) of [Pd(DPPE)(Me)(Cl)] and 125.5 mg
(1.121 mmol) of 2-methyl-2-propanethiol, sodium salt as solids. This
mixture was suspended in 10 mL of THF and stirred at room
temperature for 0.5 h. The resulting mixture was filtered through a
medium fritted funnel, and the THF was removed under vacuum. The
residual solid was dissolved in benzene, and the resulting suspension
was filtered through a medium fritted funnel. The product was obtained
as crystalline needles by crystallization from benzene layered with
pentane at room temperature (392 mg, 86.5%). 1H NMR (C6D6) δ
1.38 (virtual t, 7 Hz, 3H), 1.65-1.98 (m, 4H), 1.90 (s, 9H), 7.20 (m,
12H), 7.47 (dd, 10.0 Hz, 8 Hz, 4H), 7.96 (t, 8 Hz, 4H); 31P{1H} NMR
(C6D6) δ 50.3 (d, 21 Hz), 31.5 (d, 21 Hz).
[Pd(Ph2PCH2CH2PPh2)(SC6H4-4-Cl)(C6H4-4-n-Bu)] (19). Syn-
thesis of syn- and anti-[Pd(PPh3)(C6H4-4-n-Bu)(µ-OH)]2. To a 50
mL culture tube was added 238.5 mg (0.2680 mmol) of trans-[Pd-
(PPh3)2(C6H4-n-Bu)(I)] and 156.6 mg (0.9321 mmol) of CsOH‚H2O.
This mixture was stirred for 18 h in 35 mL of THF at room temperature
after which time the solution was filtered through Celite. The THF
was then evaporated under vacuum, and the resultant pale yellow solid
was dissolved in 2 mL of benzene. This benzene solution was poured
in a vial containing 15 mL of pentane and the mixture stirred for 1 h
at room temperature. After this time, a white solid precipitated out of
solution. The product was obtained by layering a toluene solution with
pentane at -35 °C in 69.8% (96.9 mg) yield (31P{1H} NMR (C6D6) δ
34.66 (s), 33.78 (s), relative intensity ) 2:1).
To a 20 mL vial was added 80.2 mg (0.0776 mmol) of syn- and
anti-[Pd(PPh3)(C6H4-4-n-Bu)(µ-OH)]2 and 5 mL of THF. A solution
of 4-chlorothiophenol (26.1 mg, 0.181 mmol) in 5 mL of THF was
added to the n-butyl aryl hydroxy dimer solution and stirred for 5 min.
The resultant brown solution was identified as syn- and anti-[Pd(PPh3)-
(C6H4-4-n-Bu)(µ-SC6H4-4-Cl)]2 (31P{1H} (THF) δ 28.4 (s), 27.3 (s),
relative intensity ) 1:1.5). To this solution was added 68.6 mg (0.172
mmol) of DPPE and the mixture was stirred for another 5 min, after
which time an orange solution was obtained. The THF was removed
from this orange solution under vacuum and the resultant orange solid
was dissolved in toluene and filtered through Celite. A fluffy pink
solid was obtained by layering a toluene solution with pentane at -35
°C in 50.0% (60.4 mg) yield. 1H NMR (C6D6) δ 0.93 (t, 7.3 Hz, 3H),
1.27 (m, 2H), 1.49 (m, 2H), 1.80 (m, 4H), 2.37 (t, 7.6 Hz, 2H), 6.56
(dd, 7.7 Hz, 1.8 Hz, 2H), 6.71 (d, 8.4 Hz, 2H), 6.92 (m, 7H), 7.13 (m,
11H), 7.41 (d, 8.4 Hz, 2H), 7.93 (m, 4H); 31P{1H} NMR (C6D6) δ
45.06 (d, 24.4 Hz), 35.31 (d, 24.4 Hz).
[Pd(Ph2PCH2CH2PPh2)(SC6H5)(C6H4-4-n-Bu)] (20). The product
was obtained in 86.0% (105.8 mg) yield by layering a toluene solution
with pentane at -35 °C. 1H NMR (C6D6) δ 0.87 (t, 6.9 Hz, 3H), 1.29
(m, 2H), 1.44 (m, 2H), 1.69-1.95 (m, 4H), 2.36 (t, 7.4 Hz, 2H), 6.59
(d, 7.1 Hz, 2H), 6.78-6.99 (m, 10H), 7.02-7.12 (m 5H), 7.20-7.30
(m, 6H), 6.67 (d, 7.4 Hz, 2H), 7.99 (t, 7.9 Hz, 4H); 31P{1H} NMR
(C6D6) δ 44.51 (d, 24.4 Hz), 34.59 (d, 24.4 Hz).
[Pd(Ph2PCH2CH2PPh2)(SC6H4-4-CH3)(C6H4-4-n-Bu)] (21). The
product was obtained in 70.5% (81.4 mg) yield after crystallization by
layering a toluene solution with pentane at -35 °C. 1H NMR (C6D6)
δ 0.88 (t, 7.2 Hz, 3H), 1.25 (m, 2H), 1.45 (m, 2H), 1.82 (m, 4H), 2.06
(s, 3H), 2.37 (t, 7.8 Hz, 2H), 6.60 (m, 4H), 6.85-6.99 (m, 6H), 7.02-
[Pd(Ph2PCH2CH2PPh2)(S-t-Bu)(CHC(CH3)2] (15). Complex 15
was too reactive to isolate in pure form. Pd(PPh3)2(CHC(CH3)2)(Br)
was prepared by stirring a mixture of 570.3 mg (0.7983 mmol) of Pd-
86,87
[(P(o-tolyl)3]2
and 214.4 mg (1.588 mmol) of 1-bromo-2-methyl-
propene in 10 mL of benzene followed by addition of 419.2 mg (1.600
mmol) of triphenylphosphine. The solution was filtered through Celite
after 1.5 h. [Pd(PPh3)2(CHC(CH3)2)(Br)] (31P{1H} NMR (C6D6) δ
25.18 (s)) was isolated by precipitation from pentane followed by
filtration through a medium fritted funnel and was used without further
purification. Into a 20 mL vial was added 223.1 mg (0.2915 mmol)
of Pd(PPh3)2(CHC(CH3)2)(Br) and 5 mL of benzene. Upon dissolution,
140.4 mg (0.3528 mmol) of DPPE in 2 mL of benzene was addition to
the solution, and the mixture was stirred for 5 min. [Pd(DPPE)(CHC-
(CH3)2)(Br)] (31P{1H} NMR (C6D6) δ 50.9 (d, 25.6 Hz), 28.9 (d, 25.6
Hz)) was isolated as a yellow powder by precipitation from pentane
followed by filtration through a medium fritted funnel and was used
without further purification. To a 20 mL vial was weighed 63.6 mg
(0.0995 mmol) of [Pd(DPPE)(CHC(CH3)2)(Br)] and 13.4 mg (0.120
mmol) of 2-methyl-2-propanethiol, sodium salt. This mixture was
dissolved in 5 mL of THF and stirred at room temperature for 0.5 h.
The resulting orange mixture was filtered through Celite, and the THF
was removed under vacuum. Crystallization at -35 °C from toluene
1
layered with pentane resulted in the formation of an orange solid. H
and 31P{1H} NMR spectra of this solid showed formation of the product
along with <5% of Pd(DPPE)2 and ∼10% of the alkyl sulfide. 1H
(87) Paul, F.; Patt, J.; Hartwig, J. F. J. Am. Chem. Soc. 1994, 116, 5659-
5670.
(88) Paul, F.; Patt, J.; Hartwig, J. F. Organometallics 1995, 14, 3030-
3039.