Triisopropylsilanethiol is convenient synthetic equivalent of H2S for the synthesis of alkanethiols and unsymmetrical dialkyl sulfides; used as polarityreversal catalyst in radical reactions.
1. Use as a Nucleophile: A Synthetic Equivalent of H2S.
HSTIPS is prepared in quantitative yield (98%) from the reaction
of LiSH (readily obtained by reacting H2S with n-BuLi in THF)
with TIPSCl at ?78°C.
2.Synthesis of 9-BBN-derived Alkyl and Aryl Boranes.
3.Palladium-catalyzed Cross-coupling Reactions. The Pd0-
catalyzed cross-coupling of vinyl and aryl halides with KSTIPS
affords the corresponding silyl sulfides, which can be used either
to prepare thiols or sulfides.
4.Use as Ligand in Ziegler-Natta Polymerization of Ethylene
in Solution. A medium pressure process for the polymerization of ethylene has been developed in the presence of a catalytic
system involving a monocyclopentadienyl titanium species, containing TIPSthiolate as the heteroligand and two activable ligands
(2Cl or 2Me), associated with an ionic activator such as triphenylcarbenium tetrakis(pentafluorophenyl)borate.
5.Use in Radical Reactions. The radical reduction of alkyl halides by silanes is promoted by thiols. According to Roberts, the thiol acts as a polarity-reversal catalyst.6.
