[76-86-8] · C18H15ClSi · Chlorotriphenylsilane · (MW 294.87)
(bulky silylating agent1-3)
Alternate Name: triphenylsilyl chloride.
Physical Data: mp 92-94 °C; bp 240-243 °C/35 mmHg.
Solubility: readily sol most aprotic organic solvents, although CH2Cl2 is most commonly used; reacts with H2O and other protic solvents.
Form Supplied in: colorless solid.
Handling, Storage, and Precautions: somewhat prone to hydrolysis, and should be handled and stored under an anhydrous, inert atmosphere.
Like other bulky trialkylsilyl groups, the triphenylsilyl group was introduced to serve as a hydrolytically stable protecting group for alcohols. The hydroxyl functionality can be easily derivatized using Ph3SiCl in the presence of a tertiary amine or Imidazole as a base (eqs 1 and 2).1-3
A wide variety of Grignard reagents and organolithium complexes participate in reactions with Ph3SiCl to afford organosilanes. Thus the reaction of allylmagnesium chloride with Ph3SiCl gives the allylsilane in high yield (eq 3).4 However, when hydrosilyl Grignard reagents are employed, reduction to the silane occurs (eq 4).5 Azaallyl anion6 and diazolithium salts7 can each be silylated to give the anticipated silane adducts (eqs 5 and 6). Similarly, arylsilanes8 and alkynylsilanes9-12 are produced upon silylation of the appropriate metalated13 carbanions with Ph3SiCl (eqs 7-11).
Other types of heteroatomic nucleophiles are capable of reacting with Ph3SiCl to produce the silyl derivative. For example, Sodium Dicarbonylcyclopentadienylferrate combines with Ph3SiCl to give the iron silane (eq 12).14 Silylcuprates can be prepared by lithiation of Ph3SiCl followed by treatment with copper(I) ion.15 Addition of the lithium disilylcuprate to aroyl chlorides produces the acyl silane (eq 13),16 while conjugate addition of the higher order silyl cyanocuprate to an alkynic morpholinium species was utilized for the synthesis of a heterosubstituted allenylsilane (eq 14).17
State University of New York at Buffalo, NY, USA