Bromotrimethylsilane (TMSBr)

Introduction

Bromotrimethylsilane (TMSBr) is an organosilicon compound, a silyl halide with the formula C₃H₉SiBr. Under standard conditions, it is a colorless liquid, which is stable in the absence of water. It is used as a powerful silylating agent and as a catalyst for the cleavage of ethers[1] and phosphonic/phosphoric acid alkyl esters.

Carbon–Silicon bonds (186 pm) are longer and weaker than carbon–carbon bonds (154 pm), with bond dissociation energies of 451 kJ/mol (C–Si) vs. 607 kJ/mol (C–C). The C–Si bond is polarized towards carbon due to the lower electronegativity of silicon (Si 1.90 vs. C 2.55). Some examples using the bond polarization of organo­silanes are the Hosomi–Sakurai reaction,[2] the Hiyama coupling,[3] and the Tamao–Kumada–Fleming oxidation[4] [5] [6] (certain alkyl silanes can be oxidized to alcohols).

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