Tris silane with alkyl halide

Common synthetic pathways to obtain mono-, di-, tri- and tetraalkylsilanes are reactions of the respective halogenosilanes with lithiated alkyl compounds, with alkyl-magnesium halides (Grignard reactions) and with alkyl halides in a Wurtz-Fittig-type reaction, as well as the addition of silanes to alkenes, i.e. hydrosilylation. 

Chatgilialoglu and Curran synthesized a variety of allyl tris(trimethylsilyl)silanes bearing substituents at the 2-position (Scheme 26) [70], These allylsilanes underwent reaction with alkyl halides when heated with a radical initiator to give very good yields of allylated products. The reactions were relatively sensitive to electronic effects electrophilic radicals reacted well only with electron-rich allyl silanes and vice versa. One potential drawback of this methodology is that the reactions reported were all carried out at 80 °C or above, suggesting that relatively high temperatures are necessary for efficient reaction. 

The same research group has further performed radical carbonylation reactions on the same microreactor system [36]. First, alkyl halides were initiated and effectively reacted with pressurized carbon monoxide to form carbonyl compounds. The principle was subsequently successfully extrapolated to the multicomponent coupling reactions. 1-Iodooctane, carbon monoxide and methyl vinyl ketone were reacted in the presence of 2,2 -azobis(2,4-dimethylvaleronitrile) (V-65) as an initiator and tributyltin hydride or tris(trimethylsilyl)silane (TTMSS) as catalyst (Scheme 15). 

The radical-initiated allylation of alkyl halides with allyltris(trimethylsilyl)silanes proceeds via an SH2 process mediated by a tris(trimethylsilyl)silyl radical.225 The radical-allylating agents react with alkenes, alkynes, and aldehydes via a radical chain process to give the corresponding allylsilylation products.226... 

Chatgilialoglu and Curran have found that allyltris(triniethylsilyl)silanes react with a variety of alkyl halides to provide allylation products via an Sh2 process mediated by the tris(trimethylsilyl)silyl (TTMSS) radical (Scheme 10.199) [523]. In this system the allylsilanes work as radical-allylating agents and TTMSS radical sources. We have used the reactivity of allyltris(trimefhylsilyl)silanes for allylsilyla-tion of alkenes and alkynes via a radical chain mechanism (Scheme 10.199) [524]. 

Triphenylsilyl ethers are typically prepared by the reaction of the alcohol with triphenylsilyl chloride (mp 92-94 °C) and imidazole in DMF at room temperature. The dehydrogenative silylation of alcohols can be accomplished with as little as 2 mol% of the commercial Lewis acid tris(pentaf1uorophenyl)borane and a silane such as triphenylsilane or triethylsilane [Scheme 4.98]. Primary, secondary, tertiary and phenolic hydroxyls participate whereas alkenes, alkynes, alkyl halides, nitro compounds, methyl and benzyl ethers, esters and lactones are inert under the conditions. The stability of ether functions depends on the substrate. Thus, tetrahydrofurans appear to be inert whereas epoxides undergo ring cleavage. 1,2- and 1,3-Diols can also be converted to their silylene counterparts as illustrated by the conversion 983 98.4. Hindered silanes such as tri-... 

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