Synthesis and Reactivity of Martin’s Spirosilane-Derived Chloromethylsilicate

Abstract

Pentacoordinate silicon derivatives with a chloromethyl ligand are versatile compounds that are usually obtained from the corresponding tetravalent trialkoxy- or trihalogeno(chloromethyl)silane. We describe herein the synthesis of a chloromethylsilicate bearing two Martin’s ligands readily obtained by addition of in situ generated chloromethyllithium to a spirosilane. The reactivity of this new species was evaluated and it has been established that the chloride is displaced by strong nucleophiles such as alkyllithiums and (hetero)aryllithiums. In Lewis acidic conditions, the pentacoordinate silicon species rearranges through a formal insertion of a methylene into one Si–C bond, to form a new tetravalent spirosilane with a six-membered ring. The same kind of rearrangement can be triggered also by addition of a Lewis base. The mechanism of the rearrangement in both conditions has been studied by means of DFT calculations.

Synthesis and Properties of the Perfluoroethyl Martin Silicate: Reactivity in Solution and Solid‐State Mechanochemistry

“…Pursuing our interest on the derivatization of the Martin spirosilane ([SiL 2 ] 1, L = α,α-bis(trifluoromethyl) benzenemethanolato-(À 2)C 2 ,O), shown in Figure 1.d), [22][23][24][25][26][27][28] we herein report an alternative reagent for the storage and introduction of the C 2 F 5 anion based on the use of 1. Spirosilane 1 is easily obtained from the sequential bis-deprotonation of hexafluorocumyl anion to 1, the synthesis of the corresponding perfluoroethylsilicate 3 is described as well as some properties and preliminary reactivity of 3 (Figure 1.e).…”

Me2(CH2Cl)SiCF3 Facilitated Tandem Synthesis of Oxasilacycles Featuring a Trifluoromethyl Group

“…Four major synthetic strategies have been established, including the following: the Si–O bond formation of hydroxysilanes, the C–O bond formation of silanols, the Si–C bond formation of silyl ethers, and the C–C bond formation of silyl ethers . Despite significant progress, facile construction of fluorine-containing oxasilacycles remains underdeveloped, although they have exhibited promising properties for various applications, as shown by the trifluoromethylated oxasilacycles such as Martin’s spirosilane ( A ) , or reusable silicon-based transfer agent ( B ) for cross-coupling reaction. Therefore, it is highly desirable to develop efficient protocols for the diverse synthesis of fluorinated oxasilacycles.…”