Synthesis of Organic (Trimethylsilyl)chalcogenolate Salts Cat[TMS-E] (E = S, Se, Te): the Methylcarbonate Anion as a Desilylating Agent

A high-yield synthesis of the class
of (trimethylsilyl)­chalcogenolate organic salts [Cat]­[TMS-E] (E =
S, Se, Te; Cat = BMPyr, DMPyr, NMe4, nBu3MeP) is presented. The title compounds have been prepared
by the strictly aprotic reaction between the respective bis­(trimethylsilyl)­chalcogenide
(TMS2E) and methylcarbonate ionic liquids (ILs). This constitutes
a novel reaction behavior of methylcarbonate ILs, acting as a nucleophilic
desilylating agent and a Lewis base instead of as a Brønsted
base. Thus prepared silylchalcogenolate salts represent an activated
form of the multifunctional TMS2E reactant series. Pyrrolidinium
TMS-S salts have proven to be excellent precursors for the synthesis of pyrrolidinium hexasulfides. The
scope of the desilylation reaction can be extended to other silyl-bearing
synthons such as (trimethylsilyl)­azide and (trimethylsilyl)­cyanide.