[681-84-5] · C4H12O4Si · Silicon(IV) Methoxide · (MW 152.25)
(methanol synthon in aprotic media2)
Alternate Names: tetramethyl orthosilicate; tetramethoxysilane.
Physical Data: bp 121-122 °C; mp 4-5 °C; d 1.032 g cm-3; n
Solubility: sol common organic solvents.
Form Supplied in: commercially available as a colorless liquid.
Analysis of Reagent Purity: 1H NMR.
Purification: by distillation.
Handling, Storage, and Precautions: can be stored in a glass bottle but must be protected from moisture. Can cause blindness; special eye protection is required.
Acetalization of carbonyl compounds can be achieved by using an alkoxysilane and a catalytic amount (10 mol %) of Iodotrimethylsilane (eqs 1 and 2). Silicon(IV) methoxide is convenient for use in these reactions because silicon(IV) can be readily removed from the reaction mixture as a siloxane polymer after hydrolysis.
In a related reaction, 1,2-bis(trimethylsiloxy)ethane can be used for the formation of cyclic acetals (eq 3). Ketones react with alkyl silyl ethers in the presence of a catalytic amount of Trimethylsilyl Trifluoromethanesulfonate to give the corresponding acetals; cyclohex-2-enone forms the acetal without double bond migration.3
Treatment of a mixture of an aldehyde, silicon(IV) methoxide, and Allyltrimethylsilane gives homoallyl ethers exclusively (eqs 4 and 5).4
Tohoku University, Sendai, Japan