Allylsilanes

Allyltris(trimethylsilyl)silane (158, R 1 = H); Typical Procedure: [224]
Allyl phenyl sulfide (157, R 1 = H) (30 mg, 0.2 mmol), HSi(SiMe 3) 3 (74 mg, 0.3 mmol), and
AIBN (10 mol%) were refluxed in benzene for 1 h. The consumption of the starting material
and the appearance of the products were followed byNMR or GC. Workup with 1 M
NaOH was followed bycolumn chromatography(silica gel); yield: 53 mg (92%).
4.4.40.39 Method 39:
From Allyl Sulfones
Allylsilanes have been prepared from allyl sulfones by sequential treatment with tert-butyllithium
and chlorotrimethylsilane, followed by reductive desulfonylation of the resultant
allylsulfonylsilanes with sodium/N,N-dimethylnaphthalen-1-amine in the presence of
diethylamine, use of which as proton source improves the yield and the E/Z selectivity. For
example, allylsilane 161 has been prepared from recrystallized allylsulfonylsilane 160
(Scheme 63). [225] Note that preparation of allylsilane 161 proved difficult bya host of other
techniques, including a Grignard reaction (Section 4.4.40.1), methods based on counterattacking
principles (Section 4.4.40.18), or a Julia reaction (Section 4.4.40.12). [225] The
allylsulfonylsilanes, for example, 160, can also be generated in situ, and this allows a
one-pot preparation of allylsilanes directly from allylsulfones. [225]
Scheme 63 Allylsilanes from Allyl Sulfones [225]
159
FOR PERSONAL USE ONLY
4.4.40 Allylsilanes 885
SO2Ph
1. t-BuLi, THF, Et2O, −78 oC 2. TMSCl
80%
Na/Me2NC10H7, Et2NH THF, −85 oC 84%
160
SiMe3
161 (E/Z) >10:1
SO2Ph
Trimethyl[(2E,4E)-3-methyl-5-(2,6,6-trimethylcyclohex-1-enyl)penta-2,4-dienyl]silane and
Trimethyl[(2Z,4E)-3-methyl-5-(2,6,6-trimethylcyclohex-1-enyl)penta-2,4-dienyl]silane
(161); Typical Procedure: [225]
Treatment of allyl sulfone 159 (1 g, 3 mmol) with t-BuLi (1.2 equiv) in THF/Et 2O (1:1; 50 mL)
at ±788C generated an anion, which reacted with TMSCl (3 equiv) to give silylallyl sulfone
160 as brown crystals, which could be recrystallized as pale yellow crystals from hexane;
yield: 0.96 g (80%); mp 113±1148C.
A soln containing sulfone 160 (0.1 g, 0.24 mmol) dissolved in anhyd THF (1 mL) and
Et 2NH (0.5 mL, 4.8 mmol) was added under argon at ±858C to a previouslyprepared soln
of Na/Me 2NC 10H 7 [prepared bystirring Na (8 equiv) in THF (20 mL) with Me 2NC 10H 7 (4
equiv) at ±108C under argon for 3 h]. Immediatelyafter addition of the allylsulfone to
this soln at ±858C, distilled H 2O (1 mL), followed byhexane (20 mL) were added. (At this
point the excess Na was removed from the reaction mixture.) The resulting soln was extracted
with H 2O (20 mL) and 10% HCl (2 ” 20 mL) to remove the Me 2NC 10H 7. The organic
solvents were removed under reduced pressure and the residue was purified byflash
chromatography(hexane) to give a clear oil; yield: 56 mg (84%); bp 1108C/0.4 Torr.
Sarkar, T. K., SOS, (2002) 4, 837. 2002 Georg Thieme Verlag KG
SiMe 3
for references see p 920