Allyltrimethyl silane

Trimethylsilylated allylic alcohols such as 804 react readily with allyltrimethyl-silane 82 in the presence of ZnCl2 in CH2CI2 to give, after 1.5 h at 25 °C, an approximately ca. 22 78 mixture of 805 and 806 in 94% yield, and HMDSO 7 [17]. 

The 0/7/fo-alkylation of aromatic ketones with olefins can also be achieved by using the rhodium bis-olefin complex [C5Me5Rh(C2H3SiMe3)2] 2, as shown in Equation (9).7 This reaction is applied to a series of olefins (allyltrimethyl-silane, 1-pentene, norbornene, 2,2 -dimethyl-3-butene, cyclopentene, and vinyl ethyl ether) and aromatic ketones (benzophenone, 4,4 -dimethoxybenzophenone, 3,3 -bis(trifluoromethyl)benzophenone, dibenzosuberone, acetophenone, />-chloroacetophenone, and />-(trifluoromethyl)acetophenone). 

A more recent synthesis of 197 [365] is shown in Fig. 9. Enders introduced the stereogenic centre of (S)-lactic acid into the crucial position 10 in 197. The vinylsulfone B, readily available from lactic acid, was transformed into the planar chiral phenylsulfonyl-substituted (q3-allyl)tetracarbonyliron(+l) tetra-fluoroborate C showing (IR,2S,3 )-configuration. Addition of allyltrimethyl silane yielded the vinyl sulfone D which was hydrogenated to E. Alkylation with the dioxolane-derivative of l-bromoheptan-6-one (readily available from 6-bro-mohexanoic acid) afforded F. Finally, reductive removal of the sulfonyl group and deprotection of the carbonyl group furnished 197. A similar approach was used for the synthesis of 198 [366]. 

Fig. 21 Synthesis of 4-acetamido tetrahydropyran by using allyltrimethyl silane...

Trimethylsilyl ethers and esters.i The reaction of alcohols and allyltrimethyl-silane in acetonitrile with TsOH as catalyst (70 80°, 1 3 hours) results in trimethyl-silyl ethers in 85-95% yield with elimination of propene. The same reaction with carboxylic acids results in trimclhylsilyl esters. Phenols do not undergo this reaction. 

Upon treatment with TiCl3(OCHMe2), compound 32 reacts with allyltrimethyl-silane to form ether 33 in good yield and selectivity. The chiral template is then removed by treatment with an excess of LDA affording the desired homoallylic alcohol 34 in 80-94% ee. 

Nucleophile = Et3SiH, allyltrimethyl silane, Me3SiCN, MeOH Scheme 82... 

The starting allyltrimethyl silane can be prepared in satisfactory yield by the procedure of Sommer. It can also be purchased from PCR Inc., Aldrich Chemical Company, Inc., Fluka A. G., Petrarch Systems Inc., and Tokyo Kasei Kogyo Co., Ltd. The checkers employed material from Petrarch. 

The reaction of several a,/ -unsaturated ketones with allyltrimethyl silane in either [C4Ciim][BF4] or [C4Ciim][PF6] has been compared with several classical solvents, see Scheme 9.45.[152] With indium(III) chloride as catalyst, only in some cases was a higher activity observed in the ionic liquids, but the differences relative to the commonly used solvent, dichloromethane, were small and no obvious advantage in performing the reaction in the ionic media was evident. Very high catalyst loadings, ca. 20-50 mol%, were used but no attempts were made to recycle the catalyst phase. 

METHYL KETONES Allyltrimethyl-silane. Bis(acetonitrilo)chloronitro-pailadium(II). Dicarbonylbis(triphenyl-phosphine)nickel. Dichloro-dicyano-benzoquinone. Hydrogen peroxide-Palladium acetate. Meldrum s acid. Palladium r-butyl peroxide trifluoro-acetate. Palladium(Il) chloride. 

KETO ALDEHYDES Allyltrimethyl-silane. (S)-(+)-p-Tolyl-p-tolylthiomethyl sulfoxide. 

WACKER OXIDATION Allyltrimethyl-silane. Bis(acetonitrile)chloronitro-palladiumUI). Palladium(II) chloride. Triethylborane. 

Within the past decade, diastereosolective radical reactions have become feasible and the factors contolling selectivity defined. Chiral auxiliaries for radical reactions have been recently developed in analogy to those developed for carban-ion chemistry in the 1970s and 1980s. The first example of stoichiometric use of a chiral ligand for enantioselective radical additions was recently reported by Porter and coworkers [59,60,61]. Reaction of the amide 14 with allyltrimethyl-silane at -78 °C, initiated by triethylborane, in the presence of 1 equiv. each of zinc triflate and the chiral bidentate ligand 15, provided the allylated product in a yield up to 88% and ee of 90%, Eq. (18). The presumed intermediate is the a-keto radical complexed to the chiral Lewis acid. 

The [ 2 + 2] photocycloaddition of 1,4-naphthoquinone to allyltrimethyl-silane has been described, and irradiation of 1,2-bis[trimethylsilyloxy]-... 

Displayed below is a representative mechanism for the reaction between allyltrimethyl-silane and ketone in the presence of Lewis acid TiCU. 

Allyltrimethoxysilane Allyltrimethyl silane N-(2-Aminoethyl)-3-aminopropyl methyidimethoxy silane 3-Aminopropylmethyldiethoxysilane Amyltrichlorosilane... 

Acetamide MEA Allyltrimethoxysilane Allyltrimethyl silane Aminopropyltrimethoxysilane Amyltrichlorosilane... 

Acacia Acetylated lard glyceride Acrylic acid/acrylamide copolymer Adipic acid Allyltrimethoxysilane Allyltrimethyl silane Aluminum orthophosphate N-(2-Aminoethyl)-3-aminopropyl methyidimethoxy silane 3-Aminopropylmethyldiethoxysilane Aminopropyltrimethoxysilane Ammonium hydroxide Ammonium molybdate (VI) Ammonium ricinoleate Amyltrichlorosilane Arachidyl alcohol Barium petroleum sulfonate Bis (dimethylamino) dimethylsilane 3-[Bis (2-hydroxyethyl) amino] propyltriethoxysilane Bis-(N-methylbenzamide) ethoxymethyl silane Bismuth... 

Di methyl -4,8-decadienal 212-104-5 Allyltrimethyl silane Dynasylan CA0570 212-122-3 Fumaronitrile 212-133-3... 

Work has appeared describing the addition of allyltrimethyl-silane to the protected glyceraldehyde (9). This can be carried out under chelation- or non-chelation-controlled conditions, depending upon the choice of Lewis acid, leading to three contiguous oxygenated centres, two of which have defined stereo-64... 

Liu and coworkers reported in the same year a three-component allylation of in situ generated imines [100,101]. In this case, 5mol% of copper(II) triflate (Cu(OTf)2) was used as a catalyst furnishing the corresponding Cbz-protected homoallylic amines in good to excellent yields (75-95%) from an aldehyde, a carbamate, and an allyltrimethyl silane. 

A. change of the reactivity order in Figure 11 takes place if conditions of addition rate control are employed. Hosomi, Endo and Sakurai studied the reaction of triethyl orthoformate with allyltrimethyl-silane in presence of equimolar amounts of TiCl. As expected for conditions of addition rate control, the homoallylic acetal was found to be more reactive than ethyl orthoformate, and only a 2 1 product was isolated. When we repeated this reaction with catalytic amounts of SnCl, the homoallylic acetal was obtained in 51 yield. In a similar way the other 3 > "V-unsaturated acetals shown in Figure 12 were synthesized under conditions of concentration control. 

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