Allylsilanes

HO
PPh 2
MeO
b(R)-MOP (R)-MOP-phen
[(Z)-But-2-enyl]trichlorosilane [(Z)-59]: [116]
HSiCl 3 (56 g, 0.413 mol) and Pd(PPh 3) 4 (0.93 g, 0.8 mmol) were placed in an argon-purged
autoclave (100 mL). Introduction of buta-1,3-diene (34 mL, 0.40 mol) into the vessel at
±78 8C, stirring for 6 h, and the usual workup gave the product; yield: 63.67 g (84%).
Methyldiphenyl[(S,Z)-1-phenylbut-2-enyl]silane (61): [118,121]
A 20-mL sealed tube containing a magnetic stirring bar was charged with (R)-MOP (17 mg,
0.038 mmol), [Pd 2(ç 3 -allyl) 2Cl 2] (6.4 mg, 0.035 mmol of Pd), 1-phenylbuta-1,3-diene (0.48 g,
3.6 mmol), and HSiPh 2F (0.74 g, 3.7 mmol) under argon, and the mixture was stirred at rt
(ca 208C) for 12 h. Excess MeLi in Et 2O was added to convert the Si-F group into an Si-Me
group. Quenching with sat. aq NH 4Cl, extraction, drying (Na 2SO 4), and concentration, followed
bypreparative TLC (silica gel, hexane) gave the product [66% ee, byHPLC (Daicel
Chiralcel-OD, hexane)]; yield: 0.87 g (74%); [á] D ±6.35 (c 1.51, CHCl 3).
(R)-Trichloro(cyclopent-2-enyl)silane (62, n = 1); Typical Procedure: [120,122]
Under dryN 2, HSiCl 3 (0.3 mL, 3.0 mmol) was added to a mixture of [Pd 2(ç 3 -allyl) 2Cl 2]
(0.52 mg, 0.0028 mmol Pd), (R)-MOP-phen (2.58 mg, 0.00454 mmol), and cyclopenta-1,3-diene
(0.158 g, 2.4 mmol) at 08C. The mixture was stirred at 208C for 5 d. The completion of
the reaction was confirmed byGC analysis. In vacuo bulb-to-bulb distillation of the mixture
gave the product (80% ee); yield: 0.48 g (99%); bp 105 8C/20 Torr.
4.4.40.15 Method 15:
From 1,3-Dienes by Carbosilylation
Decarbonylative coupling of an acid chloride, organodisilane, and 1,3-diene in the presence
of bis(dibenzylideneacetone)palladium(0) provides E-allylsilanes by 1,4-carbosilylation
(Scheme 28). The presence of a varietyof functional groups in the acid chloride component
is compatible with this procedure, shown in the preparation of 63 (R 1 = Ph,
4-O 2NC 6H 4, 4-AcC 6H 4) (Scheme 28). Tri- and tetrasubstituted allylsilanes are also available
by this method, if 2-methyl or 2,3-dimethylbutadiene is used as the diene component.
[123,124]
PPh 2
Scheme 28 Allylsilanes by Decarbonylative Coupling of an Acid Chloride, Disilane,
and 1,3-Diene [123,124]
R 1 COCl +
Me3Si SiMe 3 +
FOR PERSONAL USE ONLY
856 Science of Synthesis 4.4 Silicon Compounds
Pd(dba) 2
80 o C, 4 h
R1 = Ph 86%
R1 = 4-O2NC6H4 51%
R1 = 4-AcC6H4 92%
[(E)-4-Phenylbut-2-enyl]trimethylsilane (63,R 1 = Ph): [124]
1.6 M Buta-1,3-diene in toluene (0.94 mL, 1.5 mmol), Pd(dba) 2 (14 mg, 0.025 mmol), BzCl
(70 mg, 0.50 mmol), Me 3SiSiMe 3 (73 mg, 0.50 mmol), and toluene (2 mL), together with a
magnetic stirring bar, were placed under argon in a 30-mL stainless-steel autoclave containing
an inserted glass liner. An air purge was ensured bythree pressurization
Sarkar, T. K., SOS, (2002) 4, 837. 2002 Georg Thieme Verlag KG
R 1
63
SiMe 3