Uses
Bromotrimethylsilane can protect or deprotect functional groups selectively, act as silane blocking agent, which is widely used in the syntheses of drugs.
Chemical Properties
Clear yellow liquid
Physical properties
bp 79°C; d 1.188 g cm?3; n20
D 1.4240; fp 32°C.
Uses
Bromotrimethylsilane is a mild and selective reagent for cleavage of lactones, epoxides,
acetals, phosphonate esters and certain ethers; effective reagent
for formation of silyl enol ethers; can function as brominating
agent.
Amines react with TMS-Br to form
isolable adducts, which react readily with ketones to form enamines
under mild conditions (eq 15).
Uses
Powerful silylating agent
Uses
Adefovir intermediate
Preparation
although many methods are reported,
only a few are provided here: chlorotrimethylsilane undergoes
halogen exchange with either magnesium bromide in Et2O
or sodium bromide in MeCN, which allows in situ reagent
formation (eq 1); alternatively, hexamethyldisilane reacts with
bromine in benzene solution or neat, to afford only TMS-Br
with no byproducts (eq 2).4 TMS-Br may also be generated
by reaction of hexamethyldisiloxane and aluminum bromide
(eq 3).However, it should be noted that the reactivity of in
situ generated reagent appears to depend upon the method of
preparation.
General Description
Bromotrimethylsilane is used with Cl
3 to catalyze the direct allylation of a variety of alcohols with allyltrimethylsilane.
Purification Methods
Purify it by repeated fractional distillation and store it in sealed ampoules in the dark. [McCusker & Reilly J Am Chem Soc 75 1583 1953.] Also fractionate it through a 15-plate column (0.8 x 32cm packed with 1/16in single turn helices of Pt-Ir wire). [Gilliam et al. J Am Chem Soc 68 1161 1946, Pray et al. J Am Chem Soc 70 433 1948, Beilstein 4 IV 4008.]
